Linear motion guide unit

The present invention relates to miniaturization of a linear motion guide unit comprised of a guide rail made with guide grooves, and a slider allowed to travel on the guide rail by virtue of more than one rolling element.

Most linear motion guide units used extensively in diverse fields of machinery such as semiconductor manufacturing equipments, various assembly machines, inspection instruments, medical gadgets, measurement instruments, and so on are needed in years to shrink them down as minuscule or tiny as permitted in construction, even with making sure of highly precise and smooth movement between components allowed to slide relatively to one another. Latest advanced linear motion guide units have been in pursuit of maintenance-free and especially miniaturization in construction, besides improvements in operational performance including high precision, fast travel, and so on. To meet with the micromechanical requirements as stated earlier, a variety of components and parts to build the linear motion guide unit is getting smaller in construction and less in their number to reduce the assembling steps as well as make any difference in dimension between mating parts less, which might occur in assembling steps, thereby making components or parts as integral as possible. Moreover, it has been needed to relieve the carriage of the slider from many chores including tiny hole-making operation, tiny tapping operation, tiny screw-driving operation, and so on. In summary, the linear motion guide units are now one of the elementary machines practically indispensable to every machine and correspondingly they are used in a wide range of sizes and versions. Nevertheless, modern advanced micromachines needs to further shrink the linear motion guide unit down in size, even with making certain of nimble sliding operation of the slider over the guide rail.

One version of the prior linear motion guide units is disclosed in the commonly assigned Japanese Patent Laid-Open No. 2001-12465, in which a guide rail is composed of a pair of lengthwise sides and a lengthwise bottom joining the sides together with one another along their lengthwise lower edges. With the prior linear motion guide unit recited just above, a slider is comprised of a carriage mostly accommodated in a lengthwise recess defined between widthwise opposing sides of the guide rail, end caps arranged on forward and aft ends of the carriage, one to each end, and end seals attached on the end caps, one to each cap, to seal clearances between the guide rail and the end caps. The end caps and end seals are tightened together to the carriage by means of machine screws, which are screwed into matching threaded holes made in the carriage.

With the prior linear motion guide unit constructed as stated earlier, the carriage is necessarily made therein with threaded holes that are used to fasten both the end caps having turnaround passages therein and the end seals on the forward and aft ends of the carriage. Thus, the prior linear motion guide unit recited earlier is remarkably complicated in construction and further has to go through some troublesome processes of tapping into the carriage in advance to hardening of the carriage, and precise fitting, combining and mating the associated parts or components together with one another to assemble the carriage with the end caps and end seals into a unitary slider. Tapping into the carriage is especially unfit for the tiny carriage, which would experience working, assembling, and so on to finish micromechanical linear motion guide units.

Another commonly assigned Japanese Patent Laid-Open No. 2002-227840 discloses a linear motion guide unit suited to be miniaturization, in which component parts to be combined with a carriage are reduced in number while the parts are assembled together in a snap-fit manner. The slider is comprised of a carriage made up of a major upper portion and side portions depending downwards from widthwise opposing edges of the major upper portion, and a composite member including end caps facing forward and aft ends of the carriage and a covering frame integral with the end caps. The composite member is composed of a first member and a second member adapted to fit over the first member from the outside. With the linear motion guide unit constructed as stated earlier, the composite member is brought into engagement with the carriage after first engaging parts or recesses in the forward and aft ends of the carriage have fit over or conform to their mating second engaging parts or projections in the first member of the composite member.

With the linear motion guide unit recited just above, formation of the first engaging parts or recesses in the carriage is needed to fit the composite member over the carriage. Thus, the carriage has to experience working operation to make the first engaging parts prior to hardening process of the carriage to make raceway grooves on steel material. This means that the prior linear motion guide unit recited is also complicated in construction and further unfit for working, assembling operation, and so on to finish micromechanical linear motion guide units.

Another version of the prior linear motion guide units is disclosed, for example in Japanese Patent Laid-Open No. H06-147222, in which a slider striding over a linear guide tack for movement is made up of first to third components. With the linear motion guide unit recited now, the first component includes forward and aft end caps and lengthwise intermediate members joined integrally with the end caps to provide sidewise outside lower portions to define return passages. The second components has a major portion made of metallic material having a lengthwise dimension corresponding to a load-carrying raceway and a return passage of a recirculating circuit where more than one rolling element is allowed to roll through there. The second component further has widthwise opposing ridges raised integrally downwards below the major portion over the lengthwise dimension equal with the overall length of the major portion to provide sidewise inside lower portions to define return passages. The third component is made of forward and aft blocks that are used to fit into forward and aft clearances left between the end caps of the first component and their associated lengthwise end surfaces of the second component, one to each clearance.

With the linear motion guide unit constructed as stated just earlier, tapping operation on the forward and aft ends of the major portion in the second component is needed to join the second component together with both the first and third components with using screws. Thus, the prior linear motion guide unit stated just above, as with other versions recited earlier, is also complicated in construction and further unfit for working, assembling, and so on to finish micromechanical linear motion guide units.

A further another version of the prior linear motion guide arrangement is disclosed in, for example Japanese patent No. 2936166, in which a guide rail having an axis is combined with a guide carriage movable on the guide rail in the direction of the axis, which runs on the guide rail with intermediacy of an endless rolling-element circuit. With the linear motion guide arrangement recited above, the guide carriage includes a guide carriage housing to form a positioning well into which a carriage member fits together with reversing bodies.

The linear motion guide arrangement constructed as stated earlier is needed to make the positioning well, and therefore is complicated in construction and further unfit for working, assembling, and so on to finish micromechanical linear motion guide units.

The present invention, therefore, has as its primary object to overcome the shortcomings as stated earlier and in particular to provide a linear motion guide unit made much minuscule in size as well as simple in construction to meet with industrial requirement of miniaturization, even with high in desired stiffness and operating performances including smooth movement, high-precision position control, and high-speed response, compared with the linear motion guide unit constructed as disclosed in the commonly assigned Japanese Patent Laid-Open No. 2001-12465 recited earlier. More particularly, the present invention provides a linear motion guide unit in which a slider movable on a guide rail is constituted with three components of a carriage, and first and second members replacing conventional end caps to reduce the component or parts in number, and the first and second members fit over the carriage in a way they hold securely the carriage between them with using no fastening element such as screws and the like, but only conjoining means including fit-engagement, fusion welding, adhesion, and so on of the first and second members with one another.

The present invention is concerned with a linear motion guide unit; comprising a guide rail having a pair of first raceway grooves extending in lengthwise direction of the guide rail, a slider conforming to the guide rail for movement relatively to the guide rail and also having second raceway grooves in opposition to the first raceway grooves, and more than one rolling element allowed to roll through load races defined between the first and second raceway grooves, the slider being made therein with forward and aft turnaround passages and return passages, the forward and aft turnaround passages being each communicated at one end thereof with the associated load race and at the other end thereof with the associated return passage to make a recirculating circuit allowing the rolling elements to circulate through there;

wherein the slider includes a carriage made therein with the second raceway grooves and first return grooves for the return passages, a first member extended across lengthwise opposite ends of the carriage and provided at lengthwise opposite ends thereof with forward and aft turnaround surfaces to form the forward and aft turnaround passages communicated with lengthwise opposite ends of the associated second raceway groove, and a second member having thereon forward and aft turnaround grooves to form the forward and aft turnaround passages in conjunction with the forward and aft turnaround surfaces and second return grooves to form the return passages in conjunction with the first return grooves; and

wherein the first member is applied to any one surface of the carriage while the second member is applied to any other surface of the carriage to put firmly the carriage between the first and second members, and just the first and second members are joined to one another with engaging means.

In one aspect of the present invention, there is disclosed a linear motion guide unit in which the engaging means is any one selected from fit-engagement made between parts complementary to one another formed on the first and second members, fusion welding applied at least in part to a closely mated area made between the first and second members, adhesive bonding, and mechanical fastening including screws and staples. In another aspect of the present invention, a linear motion guide unit is disclosed in which the fit-engagement is performed between a hole made in any one of the first and second members and a projection raised above the other member to fit into the hole. In a further another aspect of the present invention, a linear motion guide unit is disclosed in which the projection is made to have a contour in cross section, where a circle in cross section is partially cut away on diametrically opposite secant lines to have diametrically opposite flat surfaces.

In another aspect of the present invention, there is disclosed a linear motion guide unit in which the first return grooves cut in the carriage are made on inward surfaces of fore-and-aft wings of the carriage, which are spaced away from one another widthwise of the carriage.

In another aspect of the present invention, there is disclosed a linear motion guide unit in which a guide rail is made up of a pair of lengthwise sides spaced widthwise away from each other and a bottom joined lengthwise thereof together with the sides to form a lengthwise trough of U-shape in transverse section; and wherein the first raceway grooves are cut into inward surfaces of the sides.

In another aspect of the present invention, there is disclosed a linear motion guide unit in which the carriage is made on the one surface thereof with first recesses that extend fore and aft along widthwise spaced edges of the carriage and on the other surface thereof with a second recess that extends fore and aft between the widthwise spaced wings of the carriage; wherein the first member fits at first lengthwise conjunctive portions thereof into the first recesses while the second member fits at a second lengthwise conjunctive portion thereof into the second recess; and wherein the first return grooves are cut deep into the second recess while the second raceway grooves are cut into outward sides of the carriage.

In another aspect of the present invention, there is disclosed a linear motion guide unit in which the first member includes first forward and aft end plates conforming in location to the lengthwise opposite ends of the carriage, the first forward and aft end plates having thereon the turnaround surfaces to form the turnaround passages, the first forward and aft end plates being made integral with the first lengthwise conjunctive portions that extend between the first forward and aft end plates to fit into the first recesses on the carriage, and the first forward and aft end plates being further made on their outward end surfaces thereof with any one of the projection and hole complementary to one another to join the first member to the second member.

In another aspect of the present invention, there is disclosed a linear motion guide unit in which the second member includes second forward and aft end plates and a major portion that is made integral with the second forward and aft end plates to extend between them, the second forward and aft end plates conforming in location to outward end surfaces of the first forward and aft end plates and having any one of the projection and hole in opposition to the complementary part on the first member to join together the first and second member, and wherein the major portion includes forward and aft turnaround areas merging with their associated second forward and aft end plates, and the second lengthwise conjunctive portion that extends between the forward and aft turnaround areas to fit into the second recess on the carriage, the forward and aft turnaround areas conforming in location to the lengthwise opposite ends of the carriage and having the turnaround grooves communicating with their associated load races, and the second lengthwise conjunctive portion being made therein with the second return grooves.

In a further another aspect of the present invention, there is disclosed a linear motion guide unit, in which the guide rail has the first raceway grooves that extend lengthwise on widthwise opposite sides of the guide rail, and in which the first member is applied to any one surface of the carriage while the second member is applied to any other surface of the carriage to put firmly the carriage between the first and second members, and the first and second members are joined to one another with mutual fit-engagement.

In another aspect of the present invention, a linear motion guide unit is disclosed in which the first return grooves on the carriage are made on widthwise opposite sides of the carriage. In a further another aspect of the present invention there is disclosed a linear motion guide unit in which the guide rail is made in a form of rectangle in transverse section, which is made in the lengthwise sides thereof with threaded holes that are disposed lengthwise at selected intervals and used to fasten any other part to the guide rail.

In another aspect of the present invention, there is disclosed a linear motion guide unit in which the carriage is made concaved fore and aft to fit over the guide rail; wherein the carriage is further made on the one surface thereof with first recesses that extend fore and aft along widthwise spaced edges of the carriage to fit first lengthwise conjunctive portions of the first member into the first recesses, and on the other surface thereof with second recesses that extend fore and aft along widthwise spaced edges of the carriage to fit second lengthwise conjunctive portions of the second member into the second recesses; and further in which the return grooves are cut deep into the second recesses while the second raceway grooves are made in inward surfaces surrounding the fore-and-aft concave made in the carriage.

In another aspect of the present invention, there is disclosed a linear motion guide unit in which the first member includes first forward and aft end plates conforming in location to lengthwise opposite ends of the carriage, the first forward and aft end plates having thereon the turnaround surfaces to form the turnaround passages, the first forward and aft end plates being made integral with the first lengthwise conjunctive portions that extend between the first forward and aft end plates to fit into the first recesses on the carriage, the first forward and aft end plates in combination with the first lengthwise conjunctive portions defining a first window where the one surface of the carriage is allowed to fit into there, and the first forward and aft end plates being further made on their outward end surfaces thereof with any one of the projection and hole complementary to one another to join the first member to the second member.

In another aspect of the present invention, there is disclosed a linear motion guide unit in which the second member includes second forward and aft end plates and second lengthwise conjunctive portions made integral with the second forward and aft end plates and extended between the first forward and aft end plates to fit into the second recesses on the carriage, the second forward and aft end plates conforming in location to outward end surfaces of the first forward and aft end plates and having any one of the projection and hole in opposition to the complementary part on the first member to join together the first and second member, and the second lengthwise conjunctive portions including forward and aft turnaround areas and lengthwise intermediate portions extending fore and aft between the forward and aft turnaround areas, the forward and aft turnaround areas conforming in location to the lengthwise opposite ends of the carriage and having the turnaround grooves communicating with their associated load races, and the lengthwise intermediate portions being made therein with the second return grooves, and further in which the forward and aft turnaround areas in combination with the lengthwise intermediate portions defines a second window where the other surface of the carriage is allowed to fit into there,

In a further another aspect of the present invention, there is disclosed a linear motion guide unit in which the carriage is provided on widthwise opposite sides thereof with flanges, which are made by forming the first fore-and-aft recesses and the second fore-and-aft recesses, and wherein the first member and the second member are applied to the carriage to put the flanges between the first lengthwise conjunctive portions of the first member and the second lengthwise conjunctive portions of the second member in a way the first and second conjunctive portions are not prominent sidewise over the flanges, but flush with the flanges to make sure of mechanical stiffness of the slider in widthwise direction.

With the linear motion guide unit constructed as stated earlier, the slider can be constituted with a remarkably reduced number of parts required, or three components of a carriage, upper component and lower component save for rolling elements. The upper and lower components, after applied to the carriage to put the carriage between them, are joined with the carriage altogether in a single assembling operation with the help of just fit-engagement between the upper and lower components. Thus, the slider itself may be made ultimately simple in construction as well as finished with high accuracy, even with keeping mechanical stiffness necessary for the slider, because of relieved of a likelihood of cumulative error that would be otherwise caused by assembling procedures of some components and parts. Constructional features of the present invention help ensure accurate geometric relation among the three components, even with making it easier to shrink the slider down. Thus, the present invention provides a minuscule slider that is allowed to travel with high accuracy relatively to the guide rail to deal with high-speed smooth movement of any object such as workpiece, instrument, with high accuracy and reliability.

FIG. 1 is a front elevation, partly broken away, showing a preferred embodiment of a linear motion guide unit according to the present invention:

FIG. 2 is a plan view, partly broken away, of the linear motion guide unit of FIG. 1 :

FIG. 3 is a view in side elevation of the linear motion guide unit of FIG. 1 :

FIG. 4 is a view in transverse section of the linear motion guide unit of FIG. 1 , the view being taken along the plane of the line I-I of the figure:

FIG. 5 is a view in front elevation of a carriage for the linear motion guide unit of FIG. 1 :

FIG. 6 is a plan view of the carriage of FIG. 5 :

FIG. 7 is a view in side elevation of the carriage of FIG. 5 :

FIG. 8 is a bottom view of the carriage of FIG. 5 :

FIG. 9 is a view in front elevation of an upper component in the linear motion guide unit of FIG. 1 :

FIG. 10 is a top plan view of the upper component of FIG. 9 :

FIG. 11 is a view in side elevation of the upper component of FIG. 10 :

FIG. 12 is a view in transverse section of the upper component of FIG. 10 , the view being taken along the plane of the line II-II of the figure:

FIG. 13 is a view in front elevation of a lower component in the linear motion guide unit of FIG. 1 :

FIG. 14 is a top plan view of the lower component of FIG. 13 :

FIG. 15 is a view in side elevation of the lower component of FIG. 14 :

FIG. 16 is a view in transverse section of the lower component of FIG. 14 , the view being taken along the plane of the line III-III of the figure:

FIG. 17 is a view in lengthwise section of the lower component of FIG. 14 , the view being taken along the plane of the line IV-IV of the figure:

FIG. 18 is a view in front elevation of a finished slider for the linear motion guide unit of FIG. 1 :

FIG. 19 is a plan view of the slider of FIG. 18 :

FIG. 20 is a view in side elevation of the slider of FIG. 18 :

FIG. 21 is a front elevation, partly broken away, showing a second embodiment of a linear motion guide unit according to the present invention:

FIG. 22 is a view in transverse section of the linear motion guide unit of FIG. 21 , the view being taken along the plane of the line V-V of the figure:

FIG. 23 is a view in front elevation of a carriage in the linear motion guide unit shown in FIG. 21 :

FIG. 24 is a view in front elevation of a lower component in the linear motion guide unit of FIG. 21 :

FIG. 25 is a view in front elevation of an upper component in the linear motion guide unit of FIG. 21 :

FIG. 26 is a front elevation, partly broken away, showing a third embodiment of a linear motion guide unit according to the present invention:

FIG. 27 is a top plan view, partly broken away, of the linear motion guide unit of FIG. 26 :

FIG. 28 is a view in side elevation of the linear motion guide unit of FIG. 26 :

FIG. 29 is a view in transverse section of the linear motion guide unit of FIG. 26 , the view being taken along the plane of the line VI-VI of the figure:

FIG. 30 is a view in front elevation of a carriage for the linear motion guide unit of FIG. 26 :

FIG. 31 is a view in side elevation of the carriage of FIG. 30 :

FIG. 32 is a view in bottom of the carriage shown in FIG. 30 :

FIG. 33 is a view in front elevation of a lower component for the linear motion guide unit of FIG. 26 :

FIG. 34 is a top plan view of the lower component of FIG. 33 :

FIG. 35 is a view in side elevation of the lower component of FIG. 34 :

FIG. 36 is a view in transverse section of the lower component of FIG. 34 , the view being taken along the plane of the line VII-VII of the figure:

FIG. 37 is a view in front elevation of an upper component in the linear motion guide unit of FIG. 26 :

FIG. 38 is a view in bottom of the upper component of FIG. 37 :

FIG. 39 is a view in side elevation of the upper component of FIG. 38 :

FIG. 40 is a view in transverse section of the upper component of FIG. 38 , the view being taken along the plane of the line VIII-VIII of the figure:

FIG. 41 is an enlarged fragmentary view in side elevation of an area encircled with sign (E) in the upper component of FIG. 39 : and

FIG. 42 is a front elevation, partly broken away, showing a fourth embodiment of a linear motion guide unit according to the present invention.

The present invention will be explained in detail by way of example with reference to the accompanying drawings. The linear motion guide unit according to the present invention is suited for use in relatively movable mechanics for machinery as diverse as semiconductor manufacturing machines, various assembly machines, precision machines, measuring instruments, medical instruments, micromachines, industrial robots, and so on, and more particular constructed as small as possible in size, even with keeping the desired operating performances including high stiffness, smooth movement, high-precision position control, and so on.

The present invention is motivated to further develop the technical conception disclosed in the commonly assigned Japanese Patent Laid-Open No. 2002-227840 to provide a linear motion guide unit made more simplified in construction as well as miniaturized in size, even with easier in production, high in stiffness of a slider, preferable in operating performances including smooth reciprocating movement of the slider relatively to the guide rail, simple and accurate position-control, and so forth. The linear motion guide unit of the present invention has the constructional feature in which a slider 2 is comprised of a carriage 3 , a first member or an upper component 4 , a second member or a lower component 5 , and more than one rolling element 11 , and further the carriage 3 is made thereon with no fastening means including threaded holes, mating holes, pins, and so on, which are very commonly in the existing slider to assemble the mating components together with one another, thereby helping shrink the guide unit down in size.

The first version of the linear motion guide unit according to the present invention is of the type in which a guide rail 1 is made up of a pair of lengthwise sides 6 and a bottom 7 joined lengthwise thereof together with the sides 6 to form a lengthwise trough of U-shape in transverse section while a slider 2 fits for reciprocating movement into a recess 57 defined between sides 6 in a way sinking mostly in the recess 57 . This first version of the linear motion guide unit well serves for a diversity of applications including semiconductor manufacturing machines, various assembly machines, measuring instruments, medical instruments, micromachines, and so on, and more particular is expected to make certain of stiffness enough to ensure smooth reciprocating motion as well as accurate position-control of the slider, which is made very small in construction. Moreover, the slider 2 , unlike the existing slider having a carriage 3 made with any threaded holes for fastening bolts, has no need to be made with fastening or engaging means including threaded holes, mating parts, and so on to fasten any other components to forward and aft ends 18 of the carriage 3 .

The linear motion guide unit is mainly comprised of the guide rail 1 having lengthwise first raceway grooves 12 cut into inward surfaces 25 of the widthwise opposing sides 6 , one to each inward surface, the slider 2 fit in the guide rail 1 for movement relatively to the guide rail 1 , the slider 2 having the carriage made on sidewise opposing surfaces 17 thereof with fore-and aft second raceway grooves 26 in opposition to the first raceway grooves 12 , and more than one rolling element 11 allowed to run through load races 15 defined between the first and second raceway grooves 12 , 26 . The slider 2 further includes therein forward and aft turnaround passages 35 and return passages 20 . Each turnaround passage 35 is communicated at any one end thereof with the associated load race 15 while at another end thereof with the associated return passage 20 , thereby to establish a closed circuit allowing more than one rolling element 11 to circulate through there.

The slider 2 is comprised of the carriage 3 provided therein with the second raceway grooves 26 and first return grooves 19 to form the return passages 20 , a first member or upper component 4 extending along the carriage 3 to reach the lengthwise opposing ends 18 of the carriage 3 and having turnaround surfaces 23 at forward and aft ends thereof, where the turnaround passages 35 are made to come into connection with forward and aft ends of their associated second raceway grooves 26 , and a second member or lower component 5 having turnaround grooves 34 to form the turnaround passages 35 in association with the turnaround surfaces 23 of the upper component 4 , and second return grooves 36 to form the return passages 20 in combination with their associated first return grooves 19 . Especially, the linear motion guide unit constructed as stated earlier has the constructional feature in which the carriage 3 , as shown in FIG. 4 , is held securely between the upper component 4 applied from above on a top surface or one surface 49 of the carriage 3 and the lower component 5 applied from bottom on a lower surface or another surface 50 of the carriage 3 , whereby the carriage 3 is joined together with both the upper and lower components 4 , 5 , drawing upon only engaging means of the upper component 4 and the lower component 5 . With this first version stated just earlier, the upper component 4 fits into a lengthwise recess 37 defined between second forward and aft end plates 31 .

With the linear motion guide unit constructed as stated earlier, the engaging means recited above, as shown in FIGS. 18 to 20 , is made of fastener construction where any one of mating parts on the upper and lower components 4 , 5 fit into the other.

The fastener construction is made up of a projection or hook extending from any one of the upper and lower components 4 , 5 , and a hook hole made in the other. Upon assembly, the hook is allowed to fit into the associated hook hole to join firmly the upper and lower components 4 , 5 together with one another. In the first version illustrated here, the upper component 4 is made with hooks 44 while the lower component 5 is made with hook holes 14 . The hooks 44 are provided on outward surfaces 24 of the forward and aft first end plates 41 of the upper component 4 . On each first end plate 41 , two hooks 44 are raised above the outward surface 24 on either side of the first end plate 41 , one to each side. In contrast, the hook holes 14 on the lower component 5 are made at locations matching with their associated hooks 44 . Thus, it will be understood that the upper and lower components are allowed to join securely but detachably together with one another after the hooks 44 have fit into their associated hook holes 14 .

In the first version illustrated, the engaging means is shown in the construction of fit-engagement of the hook 44 with the associated hook hole 14 . There are considered some alternatives to the engaging means illustrated in the first version. As an alternative, any staples, although not shown, may be used to join the upper component 4 and lower component 5 together with one another. Instead, fusion welding, soldering, brazing, adhesive bonding, and the similar techniques may be applied into closely mating surfaces of the upper and lower components 4 , 5 , more specially, into between the outward surface 24 of the first end plate 41 of the upper component 4 and the mating inward surface 21 of the second end plate 31 of the lower component 5 as well as into between mating surfaces 40 , 30 of the upper and lower components 4 , 5 , which come into close contact with one another. It will be also appreciated that any mechanical fasteners such as threaded fasteners or the like will be available to join together the upper and lower components 4 , 5 .

The linear motion guide unit constructed as stated earlier in the first version of the present invention is of the sort in which the guide rail 1 is formed in a U-shape in transverse section looked like a trough opened upwards. The guide rail 1 is composed of a pair of the lengthwise sides 6 spaced away widthwise from one another, and the bottom 7 joined lengthwise thereof together with the sides 6 to form a lengthwise trough of U-shape in transverse section. The lengthwise sides 6 are made on their inward surfaces 59 thereof with the raceway grooves 12 . The guide rail 1 is made with bolt holes 48 that are used to fasten the guide rail 1 to a stationary member such as a machine bed, base, machine frame and so on. A bottom surface of the guide rail 1 is finished to serve as a lower reference surface 46 while any one of widthwise opposing side surfaces of the guide rail 1 is also expected to provide a side reference surface 47 . The slider 2 fits for reciprocating movement relatively to the guide rail 1 into the recess 57 defined between sides 6 in a way sinking mostly in the recess 57 .

With the linear motion guide unit constructed as stated earlier, the carriage 3 in the slider 2 is made of a material such as metal or the like rich in mechanical stiffness, and as seen in FIGS. 4 to 8 is provided on the top surface 49 thereof with a pair of first fore-and-aft recesses 28 spaced widthwise away from one another, and on the lower surface 50 thereof with a second fore-and-aft recess 29 lying widthwise midway of the lower surface 50 . In other words, the carriage 3 is made on the top surface 49 thereof with a pair of the fore-and-aft recesses 28 to define a major middle land 51 lying between the fore-and-aft recesses 28 and strip lands 8 lying sidewise farther out of their associated fore-and-aft recesses 28 . The carriage is further composed of a major middle portion 9 and fore-and-aft wings 10 extending downwards along breadthways opposite ends of the major middle portion 9 to define the second fore-and-aft recess 29 underneath the major middle portion 9 between widthwise opposing wing ends or the lower surfaces 50 . The first fore-and-aft recesses 28 on the top surface 49 of the carriage 3 are envisaged coming into fit-engagement with first fore-and-aft conjunctive portions 42 of the upper component 4 , which will be stated later. The second fore-and-aft recess 29 defined between widthwise opposing wings 10 is expected to fit over a second fore-and-aft conjunctive portion 32 of the lower component 5 , which will be also recited later. The carriage 3 is also provided therein with the fore-and-aft return grooves 19 in order to form the return passages 20 in combination with the lower component 5 . To this end, the return grooves 19 are made in the form of a quarter of a circle in cross section extending lengthwise of the carriage 3 along inside corners on the inward surface 58 of the wings 10 between which there is made the second fore-and-aft recess 29 . On the sidewise opposing sides 17 of the carriage 3 , there are cut the raceway grooves 26 , one to each side, in opposition to the raceway grooves 12 cut in the guide rail 1 . With the linear motion guide unit constructed as stated earlier, the raceway grooves 26 is made to complete the load-carrying races 15 in conjunction with their opposed raceway grooves 12 , which allow the rolling elements 11 of balls to roll through there. The major middle land 51 of the carriage 3 has a mating surface 16 to mount any other parts such as workpiece and the like thereon. To this end, the mating surface 16 of the carriage 3 is finished to serve as upper reference surface 55 and made with threaded holes 13 that are used to fasten any other parts such as workpiece and the like to the slider 2 . Any one of widthwise opposing side surfaces 17 of the carriage 3 is also expected to provide a side reference surface 43 to mount in place other parts such as workpiece and the like thereon. The carriage 3 constructed as stated earlier is made on the forward and aft ends 18 thereof with no fastener means including threaded holes, drilled holes, recesses, raised portions and the like as in the existing slider, but made even to help shrink the linear motion guide unit down as small as permitted in size.

The upper component 4 is made of synthetic resin and as seen in FIGS. 9 to 12 composed of forward and aft end plates 41 made so as to come into close engagement with the mating forward and aft ends 18 of the carriage 3 , the forward and aft end plates 41 being make therein with the turnaround surfaces 23 to provide the turnaround passages 35 , and a pair of fore-and-aft conjunctive portions 42 extended between the forward and aft end plates 41 and connected integral with the end plates 41 in a way allowed to fit into their associated recesses 28 of the carriage 3 . The forward and aft end plates 41 have raised hooks or hook holes on their outward surfaces 24 to join the upper component 4 to the lower component 5 . With the upper component 4 illustrated in FIGS. 9 and 10 , the raised hooks 44 are shown on the forward and aft end plates 41 . The raised hooks 44 on the upper component 4 is a cylindrical projections integral with the upper component 4 , which are made together with the upper component 4 from synthetic resin in a single molding operation. As an alternative to the hooks 44 recited earlier, there may be provided another hooks 44 modified in specific contour as shown in FIG. 11 , where a circle in cross section is partially cut away on diametrically opposite secant lines to have diametrically opposite flat surfaces 45 . The modified hooks 44 of secant contour as stated just earlier is envisaged making it easier to design the mating surfaces of mold halves to form a mold cavity into which synthetic resin is poured or injected to produce the upper component 4 integral with the hooks 44 . The forward and aft end plates 41 of the upper component 4 is made to complete the turnaround passages 35 in association with the lower component 5 to allow the rolling elements 11 turning round in rolling direction. With the embodiment discussed now, the lower component 5 is made with the turnaround grooves 34 as stated later in preparation for the turnaround passages 35 . Thus, the turnaround passages 35 are completed in the slider 2 after the turnaround surfaces 23 made on the mating surface 40 of the end plates 41 have come into mating with their associated turnaround grooves 34 . The upper component 4 , as seen from FIG. 9 , is made recessed at 60 when viewed in front elevation, which is defined with inward surfaces 27 of the forward and aft end plates 41 and lower surfaces 61 of the fore-and-aft conjunctive portions 42 . On assembly of the slider 2 , the upper component 4 first fits over the carriage 3 in a way embracing the carriage 3 inside the recess 60 . The upper component 4 , as seen from FIG. 10 , is moreover made with a window 22 when viewed in plan, which is defined with the forward and aft end plates 41 and the fore-and-aft conjunctive portions 42 . On assembly of the slider 2 , the upper component 4 first fits over the carriage 3 in a way the window 22 fits over around the top surface 49 of the carriage 3 . Moreover, the forward and aft end plates 41 of the upper component 4 are made at their widthwise middle thereof with lubricant paths 38 , one to each end plate, which reach closed circuits 56 in the lower component to feed lubricant to the rolling elements 11 that run through the circuit 56 .

The lower component 5 is made of synthetic resin and as seen in FIGS. 13 to 17 composed of forward and aft end plates 31 made so as to come into close engagement with outward forward and aft mating surfaces of the end plates 31 of the upper component 4 , and a major portion 63 extending fore and aft to connect integrally with the forward and aft end plates 31 . The major portion 63 of the lower component 5 includes therein turnaround areas 33 extended fore and aft beyond the ends 18 of the carriage 3 and joining to the associated end plates 31 , and a conjunctive portion 32 expected to fit into the fore-and-aft recess 29 in the carriage 3 . The turnaround areas 33 are each made therein with the turnaround grooves 34 that communicate with their associated load races 15 , while the conjunctive portion 32 is made therein with return grooves 36 extended fore and aft to connect with the turnaround grooves 34 . On assembly of the slider 2 , the turnaround passages 35 associated with the load races 15 are completed after the turnaround areas 33 in the lower component 5 has been fitted together with the end plates 41 of the upper component 4 on their mating surfaces 30 and 40 . The turnaround areas 33 in the lower component 4 is made with the turnaround grooves 34 of roughly semicircular contour in cross section, which is somewhat larger in diametral width and in depth than the rolling elements 11 . The conjunctive portion 32 in the lower component 5 is made therein with return grooves 36 in conjunction with their associated turnaround grooves 34 , which are envisaged forming the return passages 20 . After the conjunctive portion 32 in the lower component 5 has fit into the recess 29 between the wings 10 of the carriage 3 , the turnaround areas 33 come into close engagement at their inward ends 62 with their mating ends 18 of the carriage 3 . Besides, the lower component 5 has claws 39 extending sidewise to intrude into the raceway grooves 12 on the guide rail 1 to scoop the rolling elements 11 out of the associated load races 15 .

On the end plates 31 of the lower component 5 , there are made either hooks or hook holes in opposition to their complementary parts on the upper component 4 to join counterparts together with one another. In the version illustrated in FIG. 17 , the lower component 5 is made with hook holes 14 of secant contour where a circle in cross section is partially cut away on diametrically opposite secant lines in conformity with the corresponding contour of the hooks 44 on the upper component 4 . Nevertheless, it will be appreciated that the hook holes may be made in perfect circle in cross section. The return grooves 36 in the embodiment stated now, as shown in FIGS. 4 and 16 , is made in roughly semicircular contour in cross section to get outward sides of the conjunctive portion 32 merging into the associated turn grooves 19 in the carriage 3 . In the end plates 31 of the lower component 5 , there are provided lubricant ports 52 that are connected with the lubricant paths 38 in the end plates 41 of the upper component 4 , while the conjunctive portion 63 of the lower component 5 , as shown in FIG. 14 , is made therein with lubricant passages 53 that are made open to the return grooves 36 , which is to provide the return passages 20 for the closed circuit where the rolling elements 11 are allowed to circulate through there. Moreover, the conjunctive portion 63 of the lower component 5 , as shown in FIGS. 14 and 17 , is made at the middle thereof with relief holes 54 that are located in alignment with the bolt holes 13 in the carriage 3 . The relief holes 54 , whether made bottomed or bottomless, have the advantage of keeping the tips of the fastening bolts against making contact or inroads into the conjunctive portion 63 of the lower component 5 . On assembly of the upper component 4 with the lower component 5 , the forward and aft end plates 31 of the lower component 5 are first made elastically warped to expand outwards a lengthwise distance (L) between them, and then allowed to return their initial attitude with their hook holes 14 fitting over the hooks 44 on the upper component 4 .

How to build the carriage 3 , upper component 4 and lower component 5 into the slider 2 will be explained later with reference to FIGS. 18 to 20 . The upper component 4 is first applied from above to one surface or the top surface 49 of the carriage 3 to get the forward and aft end plates 41 of the upper component 4 engaging closely with their mating end plates 18 of the carriage 3 and at the same time to allow the fore-and-aft arms 42 to fit snugly into the fore-and-aft recesses 28 cut in the top surface 49 of the carriage 3 . Then, the lower component 5 is applied from below to another surface or the bottom surface 50 of the carriage 3 to get the conjunctive portion 32 fitting into the fore-and-aft recess 29 in the carriage 3 and at the same time to bring the fore-and-aft end plates 31 of the lower component 5 into fit-engagement with the outwards surfaces 24 of the fore-and-aft end plates 31 in the lower component 5 . On combining the upper component 4 with the lower component 5 , the forward and aft end plates 31 of the lower component 5 are first made elastically warped to expand outwards a lengthwise distance (L) between their opposing inward surfaces, and then allowed to return their initial attitude with their hook holes 14 fitting over the hooks 44 on the upper component 4 . The carriage 3 , upper component 4 and lower component 5 are all joined together into the slider 2 according to the procedures of assembly as stated earlier. More than one rolling element 11 is finally introduced into the circulating circuit 56 to finish the linear motion guide unit. Meanwhile, the rolling elements 11 are introduced into the circulating circuit 56 while fitting the slider 2 into the guide rail 1 in order to keep the rolling elements 11 against falling away from the slider 2 . As an alternative, any dummy guide rail is previously incorporated in the slider 2 instead of real one and slider 2 is later transferred from the dummy guide rail to real one. Instead, any retainer band may be used to keep the rolling elements 11 against falling away from the slider 2 . With the embodiment constructed as stated earlier, although but there is provided no end seals to close any clearance left between the guide rail 1 and the slider 2 , it will be appreciated that some rooms expected to accommodate the sealing means therein may be provided between the end plates 41 of the upper component 4 and the end plates 31 of the lower component 5 .

A second embodiment of the linear motion guide unit according to the present invention will be hereinafter explained with reference to FIGS. 21 to 25 in which like and corresponding parts are referred to like reference characters suffixed with an alphabetic sign “C”. To that extent, the previous description for the first embodiment stated earlier will be applicable to the second embodiment. One major difference between the first and second versions is that a guide rail 1 C in the second embodiment is made of an elongated solid member roughly rectangular in cross section instead of the guide rail 1 in the first embodiment, which is made up of a pair of lengthwise sides 6 and a bottom 7 joined lengthwise thereof together with the sides 6 to form a lengthwise trough of U-shape in transverse section. Detailed description as for a carriage 3 C, upper component 4 C and lower component 4 C of the slider 2 C fitting over the guide rail 1 C has been previously disclosed in the commonly assigned Japanese Patent Application No.2004-158813, published as JP 2005-337425 and therefore, the following description only with significant differences in construction.

The guide rail 1 C has widthwise opposing sides 74 extending in lengthwise direction, on which are made first raceway grooves 12 C, one to each side. A slider 2 C fits over or conforms to the guide rail 1 C for movement relative to the guide rail 1 C and has second raceway grooves 26 C in opposition to the first raceway grooves 12 C. The guide rail 1 C is also made so very small in size as in guide rail 1 of the first embodiment, for example 1 mm in width and 2.5 mm in height. More particularly, the slider 2 C is distinctive be constituted with three components of a carriage 3 C, upper component 4 C and lower component 5 C to reduce the component or parts in number and shrink the slider down to minuscule size. The upper and second components 4 C, 5 C fit over the carriage 3 C in a way they grasp securely the carriage 3 C between them with no fastening element including screws, threaded holes, hooks, hook holes, and so on, but just mutual conjugation made between the upper and lower components 4 C, 5 C. Meanwhile, the commonly assigned senior Japanese Patent Application No. 2004-158813, published as JP 2005-337425, recited above discloses the slider in which the upper and lower components are joined with one another by the conjoining means relying on only fit-engagement between them.

The second embodiment discussed now features that the upper and lower components 4 C, 5 C are joined securely together with using special conjoining means including for example staples piercing through the upper and lower components 4 C, 5 C to piece together them. As alternatives, fusion welding, soldering, brazing, adhesive bonding, and the similar techniques may be applied into closely mating surfaces 70 of the upper and lower components 4 C, 5 C, more specially, into at least some of mating regions provided between outward end surfaces 24 C of forward and aft end plates 41 C of the upper component 4 C and inward end surfaces 21 C of forward and aft end plates 31 C of the lower component 5 C or between mating surfaces 40 C of the upper component 4 C and mating surfaces 30 C of the lower component 5 C. It will be appreciated that any fasteners including screws, and so on may be selected to join upper and lower components 4 C, 5 C together.

The slider 2 C is comprised of the carriage 3 C having the raceway grooves 26 C and first return grooves 19 C that are expected to provide return passages 20 C, the upper component 4 C expected to fit over any one surface or a top surface 49 C of the carriage 3 C and made at forward and aft ends thereof with turnaround surfaces 23 C to provide parts of turnaround passages 35 C, and the lower component 5 C expected to close from below another surface or a bottom surface 50 C and made with turnaround grooves 34 C to form the turnaround passages 35 C in conjunction with the turnaround surfaces 23 C and further made with second return grooves 36 C to complete the return passages 20 C in association with the first return grooves 19 C. The upper component 4 C extends along the carriage 3 C to reach the lengthwise opposing ends 18 C of the carriage 3 C, and has fore-and aft conjunctive portions 42 C equivalent in length to the overall length of the carriage 3 C and the end plates 41 C integral with the fore-and aft conjunctive portions 42 C at lengthwise opposite ends thereof to provide the turnaround surfaces 23 C that are made communicated with the forward and aft ends of the raceway grooves 26 C.

The carriage 3 , as shown in FIGS. 21 and 22 , is made at a widthwise middle area thereof with a fore-and-aft concave 71 into which the guide rail 1 C fits for traveling movement relatively to the guide rail 1 C. The carriage 3 C is made on the top surface 49 C thereof with first fore-and-aft recesses 28 C spaced sidewise away from one another to extend fore and aft on widthwise opposite side edges of the carriage 3 C in a way accommodating the conjunctive portions 42 C of the upper component 4 C therein. The carriage 3 C is further made on the bottom surface 50 C thereof with second fore-and-aft recesses 29 C spaced sidewise away from one another to extend fore and aft on widthwise opposite side edges of the carriage 3 C in a way receiving fore-and-aft conjunctive portions 32 C of the lower component 5 C. With the carriage 3 constructed as stated earlier, the return grooves 19 C are cut deep in the fore-and-aft recesses 29 C while the raceway grooves 26 C are made on inward surfaces 58 C around the fore-and-aft concave 71 . Thus, the return grooves 19 C are made in the widthwise opposite recesses 29 C of the carriage 3 C to open sidewise of the carriage 3 C. The return grooves 19 C are made semicircular in cross section by cutting deep the fore-and-aft recesses 29 C to complete the return passages 20 C where rolling elements 11 C are allowed to roll through there. This construction as stated earlier of the return grooves 19 C is also beneficial to help make production of the lower component 5 C easier. The top surface 49 C of the carriage 3 C serves as an upper surface 72 of reference to provide a mounting surface 16 C to install thereon any other object such as a workpiece and the like. In the top surface 49 C of the carriage 3 C, there are made threaded holes 13 C that are used to fasten the workpiece or the like to the carriage 3 . On both sides of the carriage 3 , there are flanges 73 raised sidewise between the upper and lower recesses 28 C, 29 C. Forward and aft ends 18 C of the carriage 3 C are made with no fastening means including hooks, hook holes, threaded holes, and so on, but made entirely flat to come into the close engagement with their mating inward surfaces 27 C of the upper component 4 C.

The first member or upper component 4 C is composed of a pair of the first end plates 41 C expected lying in opposition to the forward and aft ends 18 C of the carriage 3 C, and a pair of the first fore-and aft conjunctive portions 42 C extended between the end plates 41 C and made integral with the end plates 41 C. On the end plates 41 C, there are made the turnaround surfaces 23 C to provide parts of turnaround passages 35 C. The upper component 4 C is placed on the carriage 3 C with the fore-and-aft conjunctive portions 42 C fitting into their associated recesses 28 C on the carriage 3 C. The upper component 4 C is made with a window 22 C surrounded with the forward and aft end plates 41 C and the fore-and-aft conjunctive portions 42 C. Thus, the upper component 4 C is combined with the carriage 3 C in a way the top surface 49 C of the carriage 3 C fits into the window 22 C of the upper component 4 C. The upper component 4 C is moreover made to have sidewise opposite recesses 60 C defined inside the forward and aft end plates 41 C and the fore-and-aft conjunctive portions 42 C to fit over around the flanges 73 of the carriage 3 C. After having laid the upper component 4 C on the carriage 3 in a way the top surface 49 C of the carriage 3 C fits into the window 22 C while the fore-and-aft conjunctive portions 42 C comes into abutment against the flanges 73 of the carriage 3 C to put the flanges 73 between the upper and lower components 4 C and 5 C, the mating surfaces 40 C of the end plates 41 C come into close engagement with the mating surfaces 30 C of the lower component 5 C whereby the turnaround surfaces 23 C formed on the bottom of the end plates 41 C of the upper component 4 C is brought into combination with their associated turnaround grooves 34 C cut in turnaround areas 33 C of the fore-and-aft conjunctive portions 32 C of the lower component 5 C to complete the turnaround passages. Moreover, the forward and aft end plates 41 C of the upper component 4 C are each made at widthwise middle thereof with a fore-and-aft concave in alignment with the concave 71 in the carriage 3 C to fit over or conform to the guide rail 1 C.

The second member or lower component 5 C is composed of a pair of second forward and aft end plates 31 C and a pair of second fore-and-aft conjunctive portions 32 C spaced sidewise away from one another and integral with the forward and aft end plates 31 C. The end plates 31 C of the lower component 5 C are arranged in such a relation that their inward surfaces 21 C are allowed to come into closely mutual engagement with the outward surfaces 24 C of the end plates 41 C of the upper component 4 C. The fore-and aft conjunctive portions 32 C of the lower component 5 C are made to fit snugly into the fore-and-aft recesses 29 C, which are made by cutting away partially the bottom surface 50 C of the carriage 3 C. The fore-and-aft conjunctive portions 32 C of the lower component 5 C includes therein turnaround areas 33 C extended fore and aft beyond the ends 18 C of the carriage 3 C and made therein with the turnaround grooves 34 C leading to their associated load races 15 C, and lengthwise intermediate portions 37 C extended between the forward and aft turnaround areas 33 C to fit into the fore-and-aft recesses 29 C cut in the carriage 3 C, the lengthwise intermediate portions 37 C being made therein with the raceway grooves 36 C extending between the turnaround areas 33 C. The lower component 5 C is moreover made with a window 75 , which is surrounded with the forward and aft turnaround areas 33 C and the lengthwise intermediate portions 37 C. Upon assembly, the other surface or the bottom surface 50 C of the carriage 3 C is allowed to fit into the window 75 of the lower component 5 C.

With the linear motion guide unit of the second version constructed as stated earlier, upon assembly of the carriage 3 C together with the upper and lower components 4 C and 5 C, the mating surfaces 30 C provided on the fore-and-aft conjunctive portions 32 C merging with the end plates 31 C of the lower component 5 C come into close engagement with the mating surfaces 40 C on the bottom surfaces of the end plates 41 C of the upper component 4 C while the carriage 3 C is held confined at the flanges 73 inside the recesses 60 C that are closed from below with the fore-and-aft conjunctive portions 62 C of the lower component 5 C. Then, only the upper and lower components 4 C, 5 C are joined together by using any fastener means to keep all the carriage 3 C, upper component 4 C and the lower component 5 C in mutual combination. The fore-and-aft conjunctive portions 32 C of the lower component 5 C are made at the forward and aft ends thereof with the turnaround areas 33 C to provide the turnaround passages 35 C in combination with the upper component 4 C. The lengthwise intermediate portions 37 C to connect the turnaround areas 33 C with the lengthwise opposite ends of the fore-and-aft conjunctive portions 32 C are made integral with the turnaround areas 33 C. The lengthwise intermediate portions 37 C for the fore-and-aft conjunctive portions 32 C are made therein the return grooves 36 C. With the second embodiment constructed as stated earlier, the return grooves 36 C are made in the form of a quarter of a circle in cross section. The lower component 5 C is made with the window 75 , which is surrounded with the forward and aft turnaround areas 33 C and the sidewise opposite conjunctive portions 32 C. Upon assembly, the other surface or the bottom surface 50 C of the carriage 3 C is allowed to fit from below into the window 75 of the lower component 5 C. Moreover, the lower component 5 C is made concaved at areas between the forward and aft end plates 31 C and their associated turnaround areas 33 C in alignment with the concave 71 in the carriage 3 C to allow the lower component 5 C to fit over or conform to the guide rail 1 C.

A third version of the linear motion guide unit according to the present invention will be explained hereinafter with reference to FIGS. 26 to 41 .

The third version is also envisaged performing the same technical concept found in the first version of the present invention. Thus, like and corresponding parts to perform the identical function with the first version as stated earlier are referred to like reference characters suffixed with an alphabetic sign “B”.

The linear motion guide unit constructed according to the third version of the present invention is in general comprised of a guide rail 1 B made on widthwise opposing sides 25 B thereof with first raceway grooves 12 B, one to each side, a slider 2 B fitting over and conforming to the guide rail 1 B for movement relatively to the guide rail 1 B and made with second raceway grooves 26 B in opposition to the first raceway grooves 12 B to define load races 15 B between them, and more than one rolling element 11 B allowed to roll through the load races 15 B. The slider 2 B is provided therein with return passages 20 B and turnaround passages 35 B that are each connected at one end thereof with the associated return passage 20 B, while at another end thereof with the associated load race 15 B, thereby allowing the rolling elements 11 B to circulate through there. In other words, the recirculating circuit allowing rolling elements 11 B to run through there is made up of the load race 15 B, one turnaround passage 35 B, return passage 20 B and the other turnaround passage 35 B.

The guide rail 1 B is made very small in dimension, for example 1 mm in width and 2.5 mm in height. The guide rail 1 B, when made too small in size, could have less space thereon to form any hole that is used to fasten the guide rail 1 B to any other object such as a machine bed and the like. The miniaturized guide rail 1 B has to be mounted on any fixed object by drawing upon either any portion having nothing to do with effective traveling stroke or fusion welding, soldering, adhesive, and similar techniques. The guide rail 1 B has a bottom surface 9 B of reference and a side surface 8 B of reference, which are used to mount with accuracy the guide rail 1 B to any other fixed counterpart including a machine bed, fixed frame, and so on. In contrast, the slider 2 B has a top surface 6 B of reference and a side surface 7 B of reference, both of which are used to mount with accuracy the slider 2 B to any other member such as a workpiece and the like. The top surface 6 B and the side surface 7 B are somewhat raised above their associated upper surface and side surface of an upper component and a lower component, described in detail later, to provide an upper surface 49 B and a side surface 17 B, respectively.

The slider 2 B is constituted with three components of a carriage 3 B, first member of upper component 4 B, and second member or lower component 5 B.

The upper and lower components 4 B, 5 B fit over the carriage 3 B in a way they grasp securely the carriage 3 B between them to join the three components together with one another. The carriage 3 B has no fastening element including screws, threaded holes, hooks, hook holes, and so on. Thus, the three components to build the slider 2 B are joined together with no help of any fasteners, but with only fit-engagement of the upper component 4 B with the lower component 5 B. That is, there is no need of the provision of any fastening means including threaded holes, engaging parts complementary to each other, and similar elements on the carriage 3 B to finish the slider 2 B, as opposed to the conventional fastening techniques for building the slider. Forward and aft ends 18 B of the carriage 3 B are thus made with no additional fastening means to join the upper and lower components 4 B, 5 B thereon, but made entirely flat. In the context of the third version of the present invention, although the first member is referred to the upper component while the second member is referred to the lower component, it is to be noted that the terms “upper” and “lower” employed herein are not of intention to limit “upper” or “lower” in geometry, but for the purpose of much understanding of invention in compliance with the drawings.

More specially, the slider 2 B is comprised of the carriage 3 B made with the raceway grooves 26 B and further return grooves 19 B for the provision of return passages 20 B, the upper component 4 B disposed on any one surface or the upper surface 49 B of the carriage 3 B and made with forward and aft turnaround surfaces 23 B to form in part the turnaround passages 35 B, and the lower component 5 B located on the other surface or a lower surface 50 B of the carriage 3 B and made with turnaround grooves 34 B to form the turnaround passages 35 B in conjunction with the turnaround surfaces 23 B, the lower component 5 B being further made with second return grooves 36 B to form return passages 20 B in association with the return grooves 19 B. The upper component 4 B extends along the carriage 3 B to reach the lengthwise opposing ends 18 B of the carriage 3 B, and more specially has fore-and aft conjunctive portions 42 B equivalent in length to the overall length of the carriage 3 B and the end plates 41 B having the turnaround surfaces 23 B integral with the fore-and aft conjunctive portions 42 B at lengthwise opposite ends thereof. The turnaround surfaces 23 B of the upper component 4 B are made to communicate with forward and aft ends of the raceway grooves 26 B in the carriage 3 B, one to each end. With the linear motion guide unit constructed as stated earlier, the upper and lower components 4 B, 5 B are allowed to join together with one another by the help of fit-engagement of hooks 44 B or raised parts on any one of the mating components with hook holes 14 B or complementary parts on the other component. In the version discussed now, the upper component 4 B has the hooks 44 B while the lower component 5 B has the hook holes 14 B.

With the linear motion guide unit of the third version, the carriage 3 B, as shown in FIGS. 29 to 32 , is made at a widthwise middle area thereof with a fore-and-aft concave 27 B into which the guide rail 1 B fits for traveling movement relatively to the guide rail 1 B. The carriage 3 B is made on the top surface 49 B thereof with first fore-and-aft recesses 28 B spaced sidewise away from one another to extend fore and aft on widthwise opposite side edges of the carriage 3 B in a way accommodating the conjunctive portions 42 B of the upper component 4 B therein. The carriage 3 B is further made on the bottom surface 50 B thereof with second fore-and-aft recesses 29 B spaced sidewise away from one another to extend fore and aft on widthwise opposite side edges of the carriage 3 B in a way receiving fore-and-aft conjunctive portion 32 B of the lower component 5 B. With the carriage 3 B constructed as stated earlier, the return grooves 19 B of the carriage 3 B are cut deep in the fore-and-aft recesses 29 B to be made open outwards while the raceway grooves 26 B are cut into the inward surface of the concave 27 B. That is, the return grooves 19 B are cut into the widthwise opposite recesses 29 B so as to open sidewise outward. The return grooves 19 B are made semicircular in cross section by cutting deep the fore-and-aft recesses 29 B to complete the return passages 20 B where rolling elements 11 B are allowed to roll smoothly through there. This construction as stated earlier of the return grooves 19 B is also beneficial to help make production of the lower component 5 B easier. The top surface 49 B of the carriage 3 B serves as a top surface 6 B of reference to provide a mounting surface 16 B to install thereon any other object such as a workpiece and the like. In the top surface 16 B of the carriage 3 B, there are made threaded holes 13 B that are used to fasten the workpiece or the like to the carriage 3 B. On both sides of the carriage 3 B, there are flanges 10 B raised sidewise between the upper and lower recesses 28 B, 29 B to define outward sides 17 B, any one of which is made to provide the side surface 7 B of reference. Forward and aft ends 18 B of the carriage 3 B are made with no fastening means including hooks, hook holes, threaded holes, any raised parts and their complementary parts, and so on, but made entirely flat to come into the close engagement with their mating inward surfaces 51 B of the upper component 4 B.

The first member or upper component 4 B, as shown in FIGS. 37 to 41 , composed of a pair of first forward and aft end plates 41 B made so as to come into close engagement with the mating forward and aft ends of the carriage 3 B, and a pair of first fore-and-aft conjunctive portions 42 B extended between the forward and aft end plates 41 B and connected integral with the end plates 41 B. The forward and aft end plates 41 B are made therein with the turnaround surfaces 23 B to provide in part the turnaround passages 35 B. The upper component 4 B is laid from above on the carriage 3 B with the fore-and-aft conjunctive portions 42 B fitting into their associated recesses 28 B cut in the carriage 3 B. The upper component 4 B is made with a first window 47 B surrounded with the forward and aft end plates 41 B and the fore-and-aft conjunctive portions 42 B. Thus, the upper component 4 B is combined with the carriage 3 B in a way the upper surface 49 B of the carriage 3 B fits into the window 47 B of the upper component 4 B. The forward and aft end plates 41 B are made on their outward surfaces 24 B thereof with any one of mutually fitting parts complementary to one another to join the upper component 4 B together with the lower counterpart 5 B, or the hooks 44 B raised above the end plates 41 B in the illustrated version. The turnaround surfaces 23 B on the forward and aft end plates 41 B are expected to form the turnaround passages 35 B in conjunction with the turnaround grooves 34 B in the lower component 5 B described later.

The upper component 4 B, as shown in FIG. 37 , is made recessed at 43 B when viewed in front elevation, which is defined with the forward and aft end plates 41 B and the fore-and-aft conjunctive portions 42 B to embrace or fit over the flanges 10 B of the carriage 3 B. The upper component 4 B, as seen from FIG. 38 , is moreover made with the window 47 B when viewed in plan, which is defined with the forward and aft end plates 41 B and the fore-and-aft conjunctive portions 42 B. After having laid the upper component 4 B on the carriage 3 B in a way the top surface 49 B of the carriage 3 B fits into the window 47 B while the fore-and-aft conjunctive portions 42 B comes into abutment against the flanges 10 B of the carriage 3 B to put the flanges 10 B between the upper and lower components 4 B and 5 B, the turnaround surfaces 23 B on the bottom of the end plates 41 B of the upper component 4 B is brought into conjunction with their associated turnaround grooves 34 B cut in turnaround areas 33 B in the fore-and-aft major portions 32 B of the lower component 5 B to complete the turnaround passages 35 B. On each outward surface 24 B of forward and aft end plates 41 B of the upper component 4 B, there is a pair of raised hooks 44 B envisaged making it possible to join firmly the upper and lower components 4 B, 5 B with each other. The raised hooks 44 B on each end plate 41 B of the upper component 4 B are disposed in a way spaced sidewise away from one another make ensure secure connection between the upper and lower components 4 B, 5 B. Each raised hook 44 B is designed in a specific contour as shown in FIGS. 39 and 41 , where a circle in cross section is partially cut away on diametrically opposite secant lines to have diametrically opposite flat surfaces 46 B. This hook 44 B of secant contour as stated just earlier is envisaged making it easier to form a mold cavity into which synthetic resin is poured to produce the upper component 4 B integral with the hooks 44 B. Moreover, the forward and aft end plates 41 B of the upper component 4 B are each made at widthwise middle thereof with a fore-and-aft concave 45 B in alignment with the concave 27 B in the carriage 3 B to fit over or conform to the guide rail 1 B.

The second member or lower component 5 B, as seen in FIGS. 33 to 36 , composed of second forward and aft end plates 31 B, and a pair of second conjunctive portions 32 B spaced sidewise away from one another and each extended fore and aft to connect integrally with the forward and aft end plates 31 B. The forward and aft end plates 31 B of the lower component 5 B are made to come into close engagement at their inward surfaces 21 B with outward surfaces 24 B of the forward and aft end plates 41 B of the upper component 4 B. The forward and aft end plates 31 B are provided therein with any one of mutually complementary parts to join together the upper and lower components 4 B, 5 B. In the embodiment illustrated here, the hook holes 14 B are made in the forward and aft end plates 31 B in opposition to the mating hooks 44 B raised on the upper component 4 B. The fore-and-aft conjunctive portions 32 B of the lower component 5 B are expected to fit into the fore-and-aft recesses 29 B cut into the bottom surface 50 B of the carriage 3 B. The second conjunctive portions 32 B extends along the carriage 3 B beyond outwards the lengthwise opposing ends 18 B of the carriage 3 B, and includes therein the forward and aft turnaround areas 33 B where there are made the turnaround grooves 34 B, and lengthwise intermediate portions 37 B envisaged fitting into the fore-and-aft recesses 29 B in the carriage 3 B and made therein with the return grooves 36 B extending between the forward and aft turnaround areas 33 B. With the lower component 5 B constructed as stated earlier, moreover, there is made open a second window 38 B that extends fore and aft through between the widthwise opposite intermediate portions 37 B as well as between the widthwise opposite turnaround areas 33 B. Thus, the lower component 5 B is allowed to fit over or conform to the bottom surface 50 B of the carriage 3 B.

With the linear motion guide unit of the third version constructed as stated earlier, upon assembly of the carriage 3 B together with the upper and lower components 4 B and 5 B, the mating surfaces 30 B provided on the second conjunctive portions 32 B merging with the end plates 31 B of the lower component 5 B come into close engagement with the mating surfaces 40 B on the bottom surfaces of the end plates 41 B of the upper component 4 B while the carriage 3 B is held confined at the flanges 10 B inside the recesses 43 B that are closed from below with the second conjunctive portions 32 B of the lower component 5 B. The second conjunctive portions 32 B of the lower component 5 B includes therein the forward and aft turnaround areas 33 B to complete the turnaround passages 35 B, and the lengthwise intermediate portions 37 B integral at their forward and aft ends thereof with the turnaround areas 33 B to connect them together with one another. In the forward and aft turnaround areas 33 B of the third embodiment, there are provided the turnaround grooves 34 B of roughly semicircular contour in cross section, which is somewhat larger in diametral width and in depth than the rolling elements 11 B. Besides, the lower component 5 B has claws 39 B extending sidewise to intrude into the raceway grooves 12 B on the guide rail 1 B to scoop the rolling elements 11 B out of the associated load races 15 B. The lengthwise intermediate portions 37 B in the conjunctive portions 32 B are provided therein with the return grooves 36 B that are, as shown in FIG. 29 , made in the form of a quarter of a circle in cross section. The hook holes 14 B in the end plates 31 B are made to have any shape conforming to the corresponding contour of the hooks 44 B on the upper component 4 B. Between the conjunctive portions 32 B of the second component 5 B, when viewed in plan as in FIG. 34 , there is provided the window 38 B surrounded with the sidewise opposite intermediate portions 37 B of the conjunctive portions 32 B and the lengthwise opposite turnaround areas 33 B to allow the lower component 5 B to fit over or conform to the bottom surface 50 B of the carriage 3 B. Moreover, the lower component 5 B, when viewed in side elevation as in FIG. 35 , is made therein with a concave 22 B that extends fore and aft through the forward and aft end plates 31 B and between the widthwise opposite turnaround areas 33 B in alignment with the concave 27 B in the carriage 3 B to fit over or conform to the guide rail 1 B.

With the linear motion guide unit constructed as stated just earlier, the carriage 3 B is provided on widthwise opposite sides thereof with the flanges 10 B, which are made by forming the first fore-and-aft recesses 28 B and the second fore-and-aft recesses 29 B. The carriage 3 B with the flanges 10 B is made of metals rich in mechanical stiffness while the upper and lower components 4 B, 5 B are made of resins. With the linear motion guide unit of the third embodiment, after the upper and lower components 4 B, 5 B have been applied from above and below to the carriage 3 B, the conjunctive portions 32 B and 42 B hold the flanges 10 B between them in a geometry not prominent sidewise over the flanges 10 B, but flush with the flanges 10 B and, therefore, the slider 2 B is made ensured in mechanical stiffness in widthwise direction. Besides, all the concaves 27 B, 45 B and 22 B in the carriage 3 B, upper component 4 B and lower component 5 B are kept in alignment with one another to allow the slider 2 B to fit over or conform to the guide rail 1 B.

The linear motion guide unit constructed as stated earlier makes it easier to shrink the slider 2 B as small as allowed. The upper and lower components 4 B, 5 B, after applied from above and below to the carriage 3 B to put the carriage 3 B between them, are joined together in a single assembling operation with the help of fit-engagement of the hooks 44 B with the hook holes 14 B. As there is no need to provide any fastening means such as screws on the carriage 3 B, the slider 2 B itself may be made ultimately simple in construction as well as finished with high accuracy because of relieved of a likelihood of cumulative error that would be otherwise caused by assembling procedures of three components. Moreover, since the metallic carriage 3 B is made responsible for bearing the other parts mounted thereon across the overall breadth thereof, the slider 2 B by itself may be ensured in desired mechanical stiffness and, therefore, made miniaturized in size. The slider 2 B is allowed to shrink it down to, for example 6.5 mm in length, 4 mm in width and 2.5 mm in height and correspondingly the guide rail 1 B is made as tiny as, for example 1 mm in width and 1.4 mm in height. This miniaturization technology as stated earlier makes it possible to shrink the linear motion guide unit down to 2.5 mm in height.

Referring finally to FIG. 42 , there is illustrated a fourth version of the linear motion guide unit constructed according to the present invention. A slider 2 B in the fourth version is substantially identical with the previously described slider. Thus, the components are given the same reference characters, so that the previous description will be applicable. The guide rail is denoted with a suffix of alphabetic sign “D”. The guide rail 1 D of the fourth version is made in the form of rectangle in cross section, which is large in height, for example 3.1 mm in height. The guide rail 1 D is made in the sides thereof with threaded holes 48 D that are disposed lengthwise at selected intervals and used to fasten any other part to the guide rail 1 D.