Tool for bore diameter work

1. Field of the Invention

The present invention relates to a tool for bore diameter work, used in bore diameter work such as, for example, boring, inserting grooves, and screw-cutting.

2. Description of the Related Art

Japanese Patent Application, First Publication, No. 11-277309 discloses one example of a conventional tool for bore diameter work of this type.

In this type of tool for bore diameter work, the flat base of a throw-away insert (hereinafter abbreviated as “insert”), comprising a small-diameter rod-like section having a cutting-blade, is secured in a insert pocket at the tip portion of a long holder by a securing bolt which passes through the flat base; in addition, the side faces of the flat base are positioned by two wall faces, which stand out from the insert seat face of the insert pocket.

However, in the tool for bore diameter work described above, it is troublesome to insert and remove the insert, since the securing bolt which passes through the flat base of the insert must be extracted in order to do this.

Furthermore, since the side faces of the flat base are positioned by the two wall faces, which stand out from the insert seat face of the insert pocket, a slight difference between the shape of the insert pocket and the shape of the flat base reduces the installation rigidity of the insert, and any force sustained when carrying out cutting work (in particular, a force which is parallel to the flat base and perpendicular to the longitudinal direction of the holder) is liable to jolt the insert and reduce the positioning precision of the cutting-blade of the insert.

There are ways of increasing the installation rigidity of the insert, such as using a set bolt to press the side faces of the flat base as disclosed in Japanese Patent Application, First Publication, No. 2000-71113. However, this tool for bore diameter work has the same drawback that the insert cannot be inserted or removed without completely extracting the set bolt. Moreover, the use of the set bolt increases the number of components and makes the tool more troublesome to use.

Attempts have been made to facilitate the insertion and removal of the insert, such as in the tool for bore diameter work disclosed in Japanese Patent Application, First Publication, No. 2000-246515. However, since securing the insert in the holder by using the head of a clamp bolt to press a slope which is provided on the top face of the insert, there is point- or line-contact between the insert and the clamp bolt, and consequently, the problem of insert installation rigidity remains.

The present invention has been realized in view of the circumstances described above, and aims to provide a cutting tool in which the insert has high installation rigidity and can be easily removed and inserted.

In order to achieve the above objects, the tool for bore diameter work according to the present invention comprises a pair of insert restraining faces, provided opposite each other at a tip portion of a shank, which is pressed by a clamping unit so that the pair of insert restraining faces move closer to each other, thereby pressingly securing top and bottom faces of a throw-away insert, which directly contacts the paid of insert restraining faces. The throw-away insert comprises a substantially rod-like protrusion having a cutting-blade, which projects to the tip side of the shank. The pair of insert restraining faces have an indented or projecting V-shape parallel to the longitudinal direction of the shank, and the top and bottom faces of the throw-away insert have a projecting or indented V-shape which can connect with the pair of insert restraining faces.

According to this constitution, the insert is pressingly secured when the indented or projecting V-shaped insert restraining faces mesh with the top and bottom faces of the insert, which are shaped in correspondence therewith. Therefore, superior insert installation rigidity and insert positioning precision can be maintained.

Furthermore, since the insert restraining faces have indented or projecting V-shapes parallel to the longitudinal direction of the shank, the rigidity is especially strong against a force from the direction intersecting the longitudinal direction of the shank at the time of cutting.

Moreover, the pressing force exerted by the insert restraining faces against the top and bottom faces of the insert can be reduced by using a clamping unit to slightly loosen the clamp, thereby allowing the insert to be attached and removed easily and increasing workability.

FIG. 1 is a top view of a tool for bore diameter work according to an embodiment of the present invention.

FIG. 2 is a side view of the tool for bore diameter work of FIG. 1 .

FIG. 3 is a front view of the tool for bore diameter work of FIG. 1 .

FIG. 4 is a top view of a insert which is installed in the tool for bore diameter work of FIG. 1 .

FIG. 5 is a side view of the insert which is installed in the tool for bore diameter work of FIG. 1 .

FIG. 6 is a front view of the insert which is installed in the tool for bore diameter work of FIG. 1 .

FIG. 7 is a diagram showing how the tool for bore diameter work of FIG. 1 is used in boring work.

FIG. 8A is a front view of the tool for bore diameter work according to another embodiment of the present invention with the insert installed.

FIG. 8B is a front view of the tool for bore diameter work according to another embodiment of the present invention with the insert installed.

FIG. 8C is a front view of the tool for bore diameter work according to another embodiment of the present invention with the insert installed.

FIG. 9 is a top view of another embodiment of the insert which is installed in the tool for bore diameter work of the present invention.

FIG. 10 is a side view of the insert of FIG. 9 .

FIG. 11 is a front view of the insert of FIG. 9 .

FIG. 12A is a front view of another embodiment of the insert which is installed in the tool for bore diameter work of the present invention.

FIG. 12B is a front view of another embodiment of the insert which is installed in the tool for bore diameter work of the present invention.

FIG. 12C is a front view of another embodiment of the insert which is installed in the tool for bore diameter work of the present invention.

FIG. 13 is a diagram showing an embodiment where the present invention is applied in a tool for bore diameter work for inserting grooves.

FIG. 14 is a diagram showing an embodiment where the present invention is applied in a tool for bore diameter work for screw-cutting.

An embodiment of the present invention will be explained with reference to the accompanying drawings.

FIG. 1 is a top view of a tool for bore diameter work according to this embodiment, FIG. 2 is a side view of the tool for bore diameter work, FIG. 3 is a front view of the tool for bore diameter work, FIG. 4 is a top view of a insert which is installed in the tool for bore diameter work, FIG. 5 is a side view of the same insert, and FIG. 6 is a front view of the same insert.

As shown in FIGS. 1 to 3 , the tool for bore diameter work 10 according to this embodiment has a substantially square-column shank 11 , the tip portion 11 A of the shank 11 extending from the base side section of the shank 11 via a sloping side face 11 B to the upper side of the thick side (the up-down direction in FIGS. 2 and 3) so as to increase the thickness thereof.

A slit 12 which parallels to the top and bottom faces of the shank 11 , runs from the tip face 11 E of the shank 11 toward the base side to a position nearly touching the sloping side face 11 B, thereby dividing the tip portion 11 A of the shank 11 into two sections.

At the divided tip portion 11 A of the shank 11 , the tip portion 11 A on the upper side of the slit 12 becomes a first insert restraining section 13 , and the tip portion 11 A on the lower side of the slit 12 becomes a second insert restraining section 14 . In the first insert restraining section 13 , the slit 12 runs to the position which nearly touches the sloping side face 11 B of the shank 11 , and the root section of its base side becomes thin section. As a result, with this thin section as a fulcrum, the first insert restraining section 13 can be elastically change the shape thereof toward the second insert restraining section 14 side.

A insert installation section 15 for attaching a insert 20 (explained later) is provided at the tip portion 11 A of the shank 11 by providing openings in the tip face 11 E and one side face 11 C of the shank 11 , and cutting away the tip portion 11 A of the shank 11 along the longitudinal direction of the shank 11 so as to connect to the slit 12 . The length of the insert installation section 15 along the longitudinal direction of the shank 11 is shorter than that of the slit 12 .

The insert installation section 15 comprises a wall face 15 A which faces the same direction as one side face 11 C of the shank 11 , a side face 15 B which faces the tip face 11 E of the shank 11 in which a base face 21 B of the insert main body 21 being positioned by directly contacting the side face 15 B at the time of attaching the insert 20 , and first and second insert restraining faces 16 and 17 which face each other at the top and bottom (parallel to the thick side of the shank 11 ). Furthermore, since a slit 12 is provided in the wall face 15 A, which faces the side same as the side face 11 C of the shank 11 , the first insert restraining face 16 is provided in the first insert restraining section 13 on the upper side of the slit 12 , and the second insert restraining face 17 is provided in the second insert restraining section 14 on the lower side of the slit 12 .

The first insert restraining face 16 , provided in the first insert restraining section 13 , comprises two flat side walls 16 A; the intersection ridgeline of the side walls 16 A extends parallel to the longitudinal direction of the shank 11 , and the first insert restraining face 16 forms a projecting V-shape parallel to the longitudinal direction of the shank 11 .

That is, when viewed in cross-section at a right angle to the longitudinal direction of the shank 11 , the cross-sectional shape of the first insert restraining face 16 is a projecting V-shape, gradually protruding to the lower side as it approaches the approximate center, parallel to the width of the first insert restraining face 16 .

Furthermore, chamfering 16 B is provided at the intersection ridgeline of the wall faces 16 A in the first insert restraining face 16 .

The second insert restraining face 17 , provided in the second insert restraining section 14 , comprises two flat side walls 17 A and forms a projecting V-shaped parallel to the longitudinal direction of the shank 11 ; in addition, chamfering 16 B is provided at the intersection ridgeline of the wall faces 17 A. Thus, the second insert restraining face 17 has the same shape as the first insert restraining face 16 .

Recesses 15 C are provided at the upper and lower sides of the bottom face 15 B of the insert installation section 15 .

At the tip portion 11 A of the shank 11 , a clamp hole 18 is provided near the other side face 11 D of the shank 11 , but not connecting to the first and second insert restraining faces 16 and 17 , and passes through the tip portion 11 A of the shank 11 parallel to the thick side thereof. A clamp bolt 19 is tightly screwed into the clamp hole 18 , and the head 19 A of the clamp bolt 19 presses against the first insert restraining section 13 , which elastically changes its shape toward the second insert restraining section 14 . In other words, the first insert restraining face 16 provided on the first insert restraining section 13 , and the second insert restraining face 17 provided on the second insert restraining section 14 , elastically change their shape toward each other and press against the top face 23 and bottom face 24 of the insert 20 , which is attached in direct contact with the first and second insert restraining faces 16 and 17 .

As shown in FIGS. 4 to 6 , the insert 20 is attached to the insert installation section 15 and comprises a insert main body 21 having the shape of a substantially square column, and a protrusion 22 , which protrudes from the tip side of the insert main body 21 parallel to the longitudinal direction of the insert main body 21 .

The insert main body 21 has a top face 23 which comprises two flat wall faces 23 A, the intersection ridgeline of the wall faces 23 A and 23 A extending parallel to the longitudinal direction of the insert 20 and forming an indented V-shape, which is parallel to the longitudinal direction of the insert 20 .

That is, when viewed in cross-section at a right angle to the longitudinal direction of the insert 20 , the top face 23 has an indented V-shape, gradually protruding to the lower side as it approaches the approximate center, in a direction parallel to the width of the top face 23 . Therefore, the shape of the top face 23 corresponds to that of the first insert restraining face 16 .

Furthermore, chamfered sections 23 B are provided at the sections of the face 23 where the wall faces 23 A meet the side faces 21 A of the insert main body 21 .

The bottom face 24 of the insert main body 21 similarly comprises two wall faces 24 A, and has an indented V-shape parallel to the longitudinal direction of the insert 20 ; in addition, chamfering sections 24 B are provided at the section on the bottom face 24 where the wall faces 24 A meet the side faces 21 A of the insert main body 21 . Thus the bottom face 24 has the same shape as the second insert restraining face 17 .

Preferably, the narrow angle □ between the two flat wall faces 23 A forming the top face 23 , and the narrow angle □ between the two flat wall faces 24 A forming the top face 24 , should be between 90 to 150 degrees.

Furthermore, a relief face 25 faces the top face 23 of the insert main body 21 , and is provided at the tip of the substantially round-headed rod-like protrusion 22 , which protrudes at the tip side and is parallel to the longitudinal direction of the insert main body 21 . In addition, a cutting-blade 26 is provided at the tip side ridgeline of the relief face 25 , and protrudes outwardly from the side face 21 A of the insert main body 21 .

The insert 20 is attached to the shank 11 in the following way.

Firstly, the insert 20 is inserted into the insert installation section 15 until its base face 21 B directly contacts the lower face 15 B of the insert installation section 15 . In this state, the top face 23 of the insert main body 21 directly contacts the first insert restraining face 16 and the bottom face 24 of the insert main body 21 directly contacts the second insert restraining face 17 .

Then, by tightening the clamp bolt 19 , the head 19 A of the clamp bolt 19 presses against the first insert restraining section 13 , and the first insert restraining face 16 elastically changes shape toward the second insert restraining face 17 .

Consequently, the top face 23 and bottom face 24 of the insert 20 are pressed against the first insert restraining face 16 and second insert restraining face 17 respectively, securely pressing the insert 20 into the shank 11 .

As shown in FIG. 3, in this state, the wall faces 16 A, which form the first insert restraining face 16 , each exert a pressing force X at right angles to the wall faces 16 A against the wall faces 23 A, which form the top face 23 of the insert main body 21 . Moreover, the wall faces 17 A, which form the second insert restraining face 17 , each exert a pressing force Y at right angles to the wall faces 17 A against the wall faces 24 A, which form the bottom face 24 of the insert main body 21 .

When the insert 20 has been attached in this manner to the tool for bore diameter work 10 , the cutting-blade 26 at the tip of the protrusion 22 of the insert, which protrudes from the tip side of the shank 11 , outwardly protrudes from one side face 11 C of the shank 11 . As for example shown in FIG. 7, the protrusion 22 is inserted into an inner peripheral face 101 of a work 100 , and boring is carried out by using the cutting-blade 26 .

According to the tool for bore diameter work 10 having the constitution described above, the first and second insert restraining faces 16 and 17 press against the top and bottom faces 23 and 24 of the insert main body 21 , attached to the shank 11 , and each has a projecting V-shape parallel to the longitudinal direction of the shank. Therefore, the first insert restraining face 16 meshes with the top face 23 of the insert main body 21 , and the second insert restraining face 17 meshes with the bottom face 24 of the insert main body 21 , whereby these faces touch each other and are pressingly secured. Consequently, it becomes possible to maintain high installation rigidity of the insert 20 , and to achieve superior positioning precision of the tip of the blade.

Furthermore, since the first and second insert restraining faces 16 and 17 form a V-shape parallel to the longitudinal direction of the shank 11 , strong rigidity can be exerted against a force which intersects the longitudinal direction of the shank 11 at the time of cutting.

By using the clamp bolt 19 to slightly loosen the clamp of the first insert restraining section 13 , the pressing force exerted by the first and second insert restraining faces 16 and 17 against the top and bottom faces 23 and 24 of the insert main body 21 is reduced, allowing the insert 20 to be attached and removed easily without removing the clamp bolt 19 and thereby increasing workability.

In the tool for bore diameter work 10 described above, the top and bottom faces 23 and 24 of the insert main body 21 are contacting the first and second insert restraining faces 16 and 17 , but the constitution is not limited to this; the insert 20 can be securely pressed without contact between these faces, obtaining the same effects as described above.

For example, as shown in FIG. 8A, of the wall faces 23 A and 24 A, which constitute the top and bottom faces 23 and 24 of the insert main body 21 , only the wall faces which are near the side faces 21 A of the insert main body 21 are contacting the first and second insert restraining faces 16 and 17 . Alternatively, as shown in FIG. 8B, of the wall faces 23 A and 24 A, which constitute the top and bottom faces 23 and 24 of the insert main body 21 , only the sections near the intersection ridgelines between the wall faces 23 A and between the wall faces 24 A, are contacting the first and second insert restraining faces 16 and 17 . Alternatively, as shown in FIG. 8C, of the wall faces 23 A which constitute the top face 23 of the insert main body 21 , only the sections near the side faces 21 A of the insert main body 21 are contacting the first insert restraining face 16 , and in addition, of the wall faces 24 A which constitute the bottom face 24 of the insert main body 21 , only the sections near the intersection ridgelines between the wall faces 24 A are contacting the second insert restraining face 17 .

FIGS. 9 to 11 show a modification of the insert, installed in the shank 11 , wherein escapes are provided the top and bottom faces of the insert main body. In the following explanation, the same sections as those of the insert 20 described above are represented by the same reference numerals.

In this insert 30 , the insert main body 21 is thinner by a predetermined depth to form escape faces 23 C and 24 C except for the tip and base sections of the top face 23 and bottom face 24 .

In the tool for bore diameter work which uses the insert 30 having the escape faces 23 C and 24 C in its top face 23 and bottom face 24 , the same effects as above can be obtained. In particular, since only the insert tip and base sides of the top face 23 and the bottom face 24 are pressed by the first and second insert restraining faces 16 and 17 , the insert 30 can be firmly secured without working the top face 23 and bottom face 24 of the insert main body 21 to exactly the same shape as the first and second insert restraining faces 16 and 17 , and it is not necessary to strictly control the work precision of the insert 30 .

In this embodiment, first and second insert restraining faces 16 and 17 have projecting V-shapes parallel to the longitudinal direction of the shank 11 , and the top face 23 and bottom face 24 of the insert main body 21 have indented V-shapes in correspondence therewith, but the constitution is not restricted to this. As shown by way of example in FIG. 12A, the top face 23 of the insert main body 21 may be an indented V-shape, and the bottom face 24 , a projecting V-shape. In the alternative example shown in FIG. 12B, the top face 23 of the insert main body 21 may be a projecting V-shape, and the bottom face 24 , an indented V-shape. Furthermore, as shown in FIG. 12C, the top and bottom faces 23 and 24 of the main insert body 21 may each have a projecting V-shape. In each of these cases, the tool for bore diameter work, which comprises the first and second insert restraining faces 16 and 17 having shapes corresponding to these top and bottom faces 23 and 24 , obtains the same effects as above without any deterioration.

The explanation of this embodiment describes the tool for bore diameter work 10 for carrying out boring work, but this invention can be applied in tools for work bore diameter which are used in other bore diameter work. For example, this invention can be applied in a tool for bore diameter work for groove insertion work 40 as shown in FIG. 13, and in a tool for bore diameter work for screw-cutting work 50 as shown in FIG. 14 .