Planetary gear train of automatic transmission for vehicle

The present application claims priority to Korean Patent Application No. 10-2018-0076651, filed Jul. 2, 2018, the entire contents of which is incorporated herein for all purposes by this reference.

The present invention relates to a planetary gear train of an automatic transmission for a vehicle.

Multi-staging of a transmission is used to improve the fuel efficiency of a vehicle by facilitating operation of an engine in a more efficient region over the entire driving range of a vehicle, and to improve the driving performance of the vehicle by rapidly providing a more suitable gear ratio in a response to driver demand.

Therefore, to achieve the above-mentioned effect of multi-staging of the transmission as described above, it is preferable that an inter-stage ratio, which is a difference in gear ratio between adjacent shifting stages is appropriately secured while increasing a gear ratio span, which is the total gear ratio range which may be provided by the transmission, and that the inter-stage ratio changes linearly as much as possible.

The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and may not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Various aspects of the present invention are directed to providing a planetary gear train of an automatic transmission for a vehicle, which is configured for providing 10 forward shifting stages and a reverse stage and ensuring sufficient durability due to relatively low torque to be endured by components while ensuring a wide gear ratio span, an inter-stage ratio of a predetermined level or more, and linearity in the inter-stage ratio.

to achieve the above-described aspect, a planetary gear train of an automatic transmission for a vehicle may include: an input shaft configured to receive power; an output shaft configured to output power; a first planetary gear set having first, second, and third rotation elements; a second planetary gear set having fourth, fifth, and sixth rotation elements; a third planetary gear set having seventh, eighth, and ninth rotation elements; a fourth planetary gear set having tenth, eleventh, and twelfth rotation elements; a fifth planetary gear set having thirteenth, fourteenth, and fifteenth rotation elements; a first shaft connected to the second rotation element, the sixth rotation element, and the input shaft; a second shaft connected to the fourteenth rotation element and the output shaft; a third shaft connected to the third rotation element; a fourth shaft connected to the fourth rotation element and the seventh rotation element; a fifth shaft connected to the fifth rotation element and the thirteenth rotation element; a sixth shaft connected to the eleventh rotation element and the fifteenth rotation element; a seventh shaft connected to the first rotation element and the ninth rotation element; an eighth shaft connected to the eighth rotation element and the tenth rotation element; and a ninth shaft connected to the twelfth rotation element.

The planetary gear train may include six coupling elements for selectively connecting two shafts among the first to ninth shafts or the transmission housing and a shaft among the first to ninth shafts, and among the six coupling elements, three coupling elements may be operatively controlled to be simultaneously coupled to each other such that a specific one of the forward or reverse shifting stages is implemented.

The six coupling elements may include three clutches configured to interconnect two shafts among the first to ninth shafts, and three brakes configured to selectively connect a shaft, which is not connected to the input shaft or the output shaft among the first to ninth shafts, to the transmission housing.

The six coupling elements may include a first clutch configured between the second shaft and the third shaft, a second clutch configured between the first shaft and the fifth shaft, a third clutch configured between the fifth shaft and the seventh shaft, a first brake configured between the seventh shaft and the transmission housing, a second brake configured between the eighth shaft and the transmission housing, and a third brake configured between the ninth shaft and the transmission housing.

The six coupling elements may include: a first clutch configured between the second shaft and the third shaft, a second clutch configured between the fourth shaft and the fifth shaft, a third clutch configured between the fifth shaft and the seventh shaft, a first brake configured between the seventh shaft and the transmission housing, a second brake configured between the eighth shaft and the transmission housing, and a third brake configured between the ninth shaft and the transmission housing.

The second planetary gear set may be configured such that two of the first, fourth, and fifth shafts are selectively connectable to rotate integrally.

The first, second, and third rotation elements may include a first sun gear, a first planet carrier, and a first ring gear, the fourth, fifth, and sixth rotation elements may include a second sun gear, a second planet carrier, and a second ring gear, the seventh, eighth, and ninth rotation elements may include a third sun gear, a third planet carrier, and a third ring gear, the tenth, eleventh and twelfth rotation elements may include a fourth sun gear, a fourth planet carrier and a fourth ring gear, and the thirteenth, fourteenth, and fifteenth rotation elements may include a fifth sun gear, a fifth planet carrier, and a fifth ring gear.

The first, second, third, fourth, and fifth planetary gear sets may be disposed in the order of the first, second, third, fourth, and fifth planetary gear sets from one side to the other side thereof.

to achieve the above-described aspect, a planetary gear train of an automatic transmission for a vehicle of the present invention may include: a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, and a fifth planetary gear set, each of which may include three rotation elements; six coupling elements configured to provide a frictional force variably; and nine shafts connected to the rotation elements of the planetary gear sets.

The first shaft is directly connected to the second rotation element of the first planetary gear set, the third rotation element of the second planetary gear set, and the input shaft, the second shaft is directly connected to the second rotation element of the fifth planetary gear set and the output shaft, the third shaft is directly connected to the third rotation element of the first planetary gear set, the fourth shaft is directly connected to the first rotation element of the second planetary gear set and the first rotation element of the third planetary gear set, the fifth shaft is directly connected to the second rotation element of the second planetary gear set and the first rotation element of the fifth planetary gear set, the sixth shaft is directly connected to the second rotation element of the fourth planetary gear set and the third rotation element of the fifth planetary gear set, and the remaining three shafts are disposed in the transmission housing to be configured for being fixed.

The three shafts, which are configured for being fixed to the transmission housing, may include the seventh shaft, the eighth shaft, and the ninth shaft. The seventh shaft may be directly connected to the first rotation element of the first planetary gear set and the third rotation element of the third planetary gear set, the eighth shaft may be directly connected to the second rotation element of the third planetary gear set and the first rotation element of the fourth planetary gear set, and the ninth shaft may be directly connected to the third rotation element of the fourth planetary gear set.

Among the six coupling elements, the first clutch may be disposed between the second shaft and the third shaft, the second clutch may be disposed between the first shaft and the fifth shaft, the third clutch may be disposed between the fifth shaft and the seventh shaft, the first brake may be disposed between the seventh shaft and the transmission housing, the second brake may be disposed between the eighth shaft and the transmission housing, and the third brake may be disposed between the ninth shaft and the transmission housing.

Among the six coupling elements, the first clutch may be disposed between the second shaft and the third shaft, the second clutch may be disposed between the fourth shaft and the fifth shaft, the third clutch may be disposed between the fifth shaft and the seventh shaft, the first brake may be disposed between the seventh shaft and the transmission housing, the second brake may be disposed between the eighth shaft and the transmission housing, and the third brake may be disposed between the ninth shaft and the transmission housing.

The first to fifth planetary gear sets may be disposed in the order of the first planetary gear set, the second planetary gear set, the third planetary gear set, the fourth planetary gear set, and the fifth planetary gear set in the axial direction of the input shaft and the output shaft.

The rotation elements of each of the first to fifth planetary gear sets may be disposed in the order of the first rotation elements, the second rotation elements, and the third rotation elements toward the radially external side from the rotation center.

A planetary gear train of an automatic transmission for a vehicle according to an exemplary embodiment of the present invention forms shifting stages of forward 10 speeds and 1 reverse speed and has a gear ratio span of 9.6. Thus, the fuel efficiency of the vehicle may be improved by making it possible to drive the engine mainly in a more efficient region.

Furthermore, according to an exemplary embodiment of the present invention, it is possible to achieve the minimum inter-stage ratio of 1.137 or more and linearity in the change of the inter-stage ratio according to the change of the shifting stage. Thus, vehicle acceleration and rhythm of engine speed before and after shifting may be improved, so that the driving performance of the vehicle may be maximized.

Furthermore, according to an exemplary embodiment of the present invention, it is possible to ensure sufficient durability due to relatively low torque to be endured by components while ensuring a wide gear ratio span, an inter-stage ratio of a predetermined level or more, and linearity in the inter-stage ratio.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

The above and other aspects, features and advantages present invention

FIG. 1 is a view exemplarily illustrating various exemplary embodiments of a planetary gear train of an automatic transmission for a vehicle according to an exemplary embodiment of the present invention;

FIG. 2 is an operation table of the planetary gear train of FIG. 1 ;

FIG. 3 is a view exemplarily illustrating various exemplary embodiments of a planetary gear train of an automatic transmission for a vehicle according to an exemplary embodiment of the present invention.

It may be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as included herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particularly intended application and use environment.

In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments of the present invention, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the other hand, the invention(s) is/are intended to cover not only the exemplary embodiments of the present invention, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

Referring to FIG. 1 , a planetary gear train of an automatic transmission for a vehicle of the present invention includes: an input shaft IN configured to receive power from a power source such as an engine or the like; an output shaft OUT configured to output power; a first planetary gear set PG 1 including first, second, and third rotation elements; a second planetary gear set PG 2 including fourth, fifth, and sixth rotation elements; a third planetary gear set PG 3 including seventh, eighth, and ninth rotation elements; a fourth planetary gear set PG 4 including tenth, eleventh, and twelfth rotation elements; and a fifth planetary gear set PG 5 including the thirteenth, fourteenth, and fifteenth rotation elements.

The planetary gear train includes: a first shaft SH 1 connected to the second rotation element, the sixth rotation element, and the input shaft IN; a second shaft SH 2 connected to the fourteenth rotation element and the output shaft OUT; a third shaft SH 3 connected to the third rotation element; a fourth shaft SH 4 connected to the fourth rotation element and the seventh rotation element; a fifth shaft SH 5 connected to the fifth rotation element and the thirteenth rotation element; a sixth shaft SH 6 connected to the eleventh rotation element and the fifteenth rotation element; a seventh shaft SH 7 connected to the first rotation element and the ninth rotation element; an eighth shaft SH 8 connected to the eighth rotation element and the tenth rotation element; and a ninth shaft SH 9 connected to the twelfth rotation element.

The first to fifth planetary gear sets PG 1 to PG 5 are disposed in the order of the first planetary gear set PG 1 , the second planetary gear set PG 2 , the third planetary gear set PG 3 , the fourth planetary gear set PG 4 , and the fifth planetary gear set PG 5 from one side toward the other side thereof with respect to an engine side.

That is, a power source such as an engine is connected to the second rotation element of the first planetary gear set PG 1 via the input shaft IN and the first shaft SH 1 to provide power. The power supplied as described above is appropriately shifted through the configuration of the present invention in which the first planetary gear set PG 1 , the second planetary gear set PG 2 , the third planetary gear set PG 3 , the fourth planetary gear set PG 4 , and the fifth planetary gear set PG 5 are disposed in order, and is then drawn to the output shaft OUT through the fourteenth rotation element of the fifth planetary gear set PG 5 and the second shaft SH 2 .

Each of the first planetary gear set PG 1 , the second planetary gear set PG 2 , a third planetary gear set PG 3 , the fourth planetary gear set PG 4 , and the fifth planetary gear set PG 5 , which form the planetary gear train, is constituted as a single pinion planetary gear set having three rotation elements.

The planetary gear train is mounted in a transmission housing HS, a torque converter may be provided between the power source and the input shaft IN, and the power drawn to the output shaft OUT may be transmitted to a drive wheel of the vehicle through a differential.

The planetary gear train includes six coupling elements for selectively connecting two shafts among the first to ninth shafts SH 1 to SH 9 or the transmission housing and a shaft among the first to ninth shafts SH 1 to SH 9 , and among the six coupling elements, three coupling elements are operatively controlled to be simultaneously coupled to each other such that a specific one of the forward or reverse shifting stages is implemented.

That is, in implementing any one of 1 to 10 forward shifting stages and an R stage, which is a reverse stage, as illustrated in FIG. 2 , it is possible to combine three specified coupling elements among the six coupling elements to implement a corresponding shifting stage.

Of course, the planetary gear train is configured to enable CLUTCH-TO-CLUTCH shifting in which when shifting to an adjacent shifting stage among the shifting stages, shifting is performed by releasing one coupling element, at the current shifting stage, from the three coupling elements required for implementing each shifting stage, and at the same time, by coupling another coupling element at a target shifting stage.

The six coupling elements include three clutches that connect two shafts among the first to ninth shafts SH 1 to SH 9 , and three brakes that selectively connect the transmission housing and a shaft which is not connected to the input shaft IN or the output shaft OUT among the first to ninth shafts SH 1 to SH 9 .

In the various exemplary embodiments of FIG. 1 , the six coupling elements include a first clutch CL 1 configured between the second shaft SH 2 and the third shaft SH 3 , a second clutch CL 2 configured between the first shaft SH 1 and the fifth shaft SH 5 , a third clutch CL 3 configured between the fifth shaft SH 5 and the seventh shaft SH 7 , a first brake B 1 configured between the seventh shaft SH 7 and the transmission housing, a second brake B 2 configured between the eighth shaft SH 8 and the transmission housing, and a third brake B 3 configured between the ninth shaft SH 9 and the transmission housing.

The various exemplary embodiments of FIG. 3 is different from the various exemplary embodiments only in the arrangement of the second clutch CL 2 among the six coupling element and the other configuration of the various exemplary embodiments is the same as that of the various exemplary embodiments. In the various exemplary embodiments of the present invention, the six coupling elements include a first clutch CL 1 configured between the second shaft SH 2 and the third shaft SH 3 , a second clutch CL 2 configured between the fourth shaft SH 4 and the fifth shaft SH 5 , a third clutch CL 3 configured between the fifth shaft SH 5 and the seventh shaft SH 7 , a first brake B 1 configured between the seventh shaft SH 7 and the transmission housing, a second brake B 2 configured between the eighth shaft SH 8 and the transmission housing, and a third brake B 3 configured between the ninth shaft SH 9 and the transmission housing.

In both of the various exemplary embodiments of the present invention, the second planetary gear set PG 2 is configured such that two of the first, fourth, and fifth shafts SH 5 are selectively connectable to rotate integrally.

The first, second, and third rotation elements include a first sun gear S 1 , a first planet carrier C 1 , and a first ring gear R 1 , the fourth, fifth, and sixth rotation elements include a second sun gear S 2 , a second planet carrier C 2 , and a second ring gear R 2 , the seventh, eighth, and ninth rotation elements include a third sun gear S 3 , a third planet carrier C 3 , and a third ring gear R 3 , the tenth, eleventh and twelfth rotation elements include a fourth sun gear S 4 , a fourth planet carrier C 4 , and a fourth ring gear R 4 , and the thirteenth, fourteenth, and fifteenth rotation elements include a fifth sun gear S 5 , a fifth planet carrier C 5 , and a fifth ring gear R 5 .

The planetary gear train of an automatic transmission for a vehicle according to an exemplary embodiment of the present invention configured as described above implements shifting stages according to an operation table as represented in FIG. 2 .

The first shifting stage is implemented by causing the first brake B 1 , the second brake B 2 , and the third brake B 3 to be engaged with each other.

The power input to the first planet carrier C 1 of the first planetary gear set PG 1 through the input shaft IN and the first shaft SH 1 is transmitted to the second ring gear R 2 of the second planetary gear set PG 2 . Since the third ring gear R 3 of the third planetary gear set PG 3 is fixed by the first brake B 1 and the third planet carrier C 3 is fixed by the second brake B 2 , the third sun gear S 3 is also in the fixed state, and thus, the second sun gear S 2 connected to the third sun gear S 3 via the fourth shaft SH 4 is also in the fixed state. Therefore, the power input to the second ring gear R 2 is decelerated by the second planet carrier C 2 and transmitted to the fifth sun gear S 5 of the fifth planetary gear set PG 5 through the fifth shaft SH 5 .

Since the fourth sun gear S 4 of the fourth planetary gear set PG 4 is fixed by the second brake B 2 and the fourth ring gear R 4 is fixed by the third brake B 3 , the fourth planet carrier C 4 is also fixed and the fifth ring gear R 5 connected to the fourth planet carrier C 4 via the sixth shaft SH 6 is also in the fixed state.

Therefore, the power transmitted to the fifth sun gear S 5 is decelerated again in the fifth planet carrier C 5 and is drawn out while forming the first shifting stage with the second shaft SH 2 and the output shaft OUT.

Shifting to the second shifting stage is implemented by causing the first brake B 1 to be released and the second clutch CL 2 to be engaged.

All the rotation elements of the second planetary gear set PG 2 are integrated and rotated by the engagement of the second clutch CL 2 , and the power of the second planetary gear set PG 2 is transmitted to the fifth sun gear S 5 through the fifth shaft SH 5 connected to the second planet carrier C 2 .

The fourth sun gear S 4 and the fourth ring gear R 4 of the fourth planetary gear set PG 4 are fixed by the second brake B 2 and the third brake B 3 , respectively. Thus, the fourth planet carrier C 4 is also in the fixed state, and thus the fifth sun gear S 5 is also in the fixed state.

Therefore, the power supplied to the fifth sun gear S 5 is decelerated again in the fifth planet carrier C 5 and is drawn out while forming the second shifting stage with the second shaft SH 2 and the output shaft OUT.

Shifting to the third shifting stage is implemented by causing the second brake B 2 to be released and the first brake B 1 to be engaged.

The power of the second planetary gear set PG 2 integrated by the engagement of the second clutch CL 2 is transmitted to the fifth sun gear S 5 through the fifth shaft SH 5 and is transmitted to the third sun gear S 3 through the fourth shaft SH 4 .

Since the third ring gear R 3 is fixed by the first brake B 1 , the power supplied to the third sun gear S 3 is decelerated by the third planet carrier C 3 and is transmitted to the fourth sun gear S 4 via the eighth shaft SH 8 . Since the fourth ring gear R 4 is fixed by the third brake B 3 , the power of the fourth sun gear S 4 is decelerated by the fourth planet carrier C 4 and is transmitted to the fifth ring gear R 5 .

Accordingly, the fifth planetary gear set PG 5 receives torque in parallel through the fifth sun gear S 5 and the fifth ring gear R 5 , and forms the output of the third shifting stage through the fifth planet carrier C 5 such that the output drawn out through the second shaft SH 2 and the output shaft OUT.

By implementing the torque parallel scheme which causes power to be input in parallel to the two rotation elements of a planetary gear set as described above, the torque to be endured by each of the rotation elements of the planetary gear set is reduced, so that durability and efficiency of the components forming the planetary gear train may be improved.

Shifting to the fourth shifting stage is implemented by causing the first brake B 1 to be released and the third clutch CL 3 to be engaged.

All the rotation elements of the second planetary gear set PG 2 are integrated by the engagement of the second clutch CL 2 , the second sun gear S 2 is integrally connected to the third sun gear S 3 through the fourth shaft SH 4 , and the second planet carrier C 2 is connected to the third ring gear R 3 by the engagement of the third clutch CL 3 . Consequently, the third sun gear S 3 and the third ring gear R 3 are restrained at the same rotation speed such that all the elements of the third planetary gear set PG 3 rotate integrally.

The third planet carrier C 3 of the third planetary gear set PG 3 transmits power to the fourth sun gear S 4 through the eighth shaft SH 8 , and the fourth ring gear R 4 is fixed by the third brake B 3 . Thus, the power of the fourth sun gear S 4 is decelerated through the fourth planet carrier C 4 and the sixth shaft SH 6 and is supplied to the fifth ring gear R 5 .

Accordingly, the fifth planetary gear set PG 5 receives torque in parallel by the fifth sun gear S 5 and the fifth ring gear R 5 , and provides the torque to the second shaft SH 2 and the output shaft OUT by forming the fourth shifting stage with the fifth planet carrier C 5

Shifting to the fifth shifting stage is implemented by causing the third clutch CL 3 to be released and the first clutch CL 1 to be engaged.

When the fourth ring gear R 4 fixed by the third brake B 3 provides a reactive force, since the second clutch CL 2 is engaged, the power transmitted to the first shaft SH 1 is transmitted to the fifth shaft SH 5 through the second ring gear R 2 and the second planet carrier C 2 to arrive at the fifth sun gear S 5 . The power transmitted to the fifth planet carrier C 5 through the clutch CL 1 through the first ring gear R 1 , the third shaft SH 3 , and the first clutch CL 1 is drawn out through the second shaft SH 2 and the output shaft OUT by forming the fifth shifting stage with the power transmitted to the fifth sun gear S 5 .

Shifting to the sixth shifting stage is implemented by causing the second clutch CL 2 to be released and the third clutch CL 3 to be engaged.

The power provided to the input shaft IN and the first shaft SH 1 is transmitted to the fifth sun gear S 5 through the first sun gear S 1 of the first planetary gear set PG 1 , the seventh shaft SH 7 , the third clutch CL 3 , and the fifth shaft SH 5 and is transmitted to the fifth planet carrier C 5 through the first ring gear R 1 , the third shaft SH 3 , the first clutch CL 1 , and the second shaft SH 2 . The fifth sun gear S 5 receives, through the sixth shaft SH 6 , a reactive force provided from the fourth ring gear R 4 fixed by the third brake B 3 , causing output of the sixth shifting stage to be drawn out through the fifth planet carrier C 5 and the second shaft SH 2 .

Shifting to the seventh shifting stage is implemented by causing the third brake B 3 to be released and the second clutch CL 2 to be engaged.

All the rotation elements of the first planetary gear set, the second planetary gear set, and the third planetary gear set are integrated and rotated by the engagement of all the first clutch CL 1 , the second clutch CL 2 , and the third clutch CL 3 . Accordingly, the second shaft SH 2 connected to the fifth planet carrier C 5 and the fifth shaft SH 5 connected to the fifth sun gear S 5 are also rotated at the same speed. Consequently, all the rotation elements of the fifth planetary gear set PG 5 also integrally rotate to be coincide with the speed of the input shaft IN, implementing the seventh stage of 1:1 gear ratio.

Shifting to the eighth shifting stage is implemented by causing the second clutch CL 2 to be released and the second brake B 2 to be engaged.

The power provided to the input shaft IN and the first shaft SH 1 is transmitted to the fifth sun gear S 5 through the first sun gear S 1 of the first planetary gear set PG 1 , the seventh shaft SH 7 , the third clutch CL 3 , and the fifth shaft SH 5 and is transmitted to the fifth planet carrier C 5 through the first ring gear R 1 , the third shaft SH 3 , the first clutch CL 1 , and the second shaft SH 2 . The fourth sun gear S 4 is fixed by the second brake B 2 and provides a reactive force to the fifth sun gear S 5 through the sixth shaft SH 6 , causing the power of the eighth shifting stage to be drawn out through the fifth planet carrier C 5 and the second shaft SH 2 .

Shifting to the ninth shifting stage is implemented by causing the third clutch CL 3 to be released and the first brake B 1 to be engaged.

Since the first sun gear S 1 is fixed by the first brake B 1 , the power transmitted to the first shaft SH 1 and the first planet carrier C 1 is accelerated by the first ring gear R 1 and is transmitted to the fifth planet carrier C 5 through the shaft SH 3 and the first clutch CL 1 , allowing the output of the ninth shifting stage to be formed with the output shaft OUT.

Shifting to the tenth shifting stage is implemented by causing the first brake B 1 to be released and the second clutch CL 2 to be engaged.

The power of the first shaft SH 1 is provided to the fifth sun gear S 5 through the second clutch CL 2 and the fifth shaft SH 5 and is transmitted to the fifth planet carrier C 5 through the first ring gear R 1 , the third shaft SH 3 , and the first clutch CL 1 , being accelerated compared to the power transmitted to the fifth sun gear S 5 and drawn out to the output shaft OUT while forming the tenth shifting stage.

The R-stage, which is the reverse stage, is implemented by causing the third clutch CL 3 , the first brake B 1 , and the third brake B 3 to be engaged with each other.

Since the second planet carrier C 2 is fixed by the first brake B 1 , the power transmitted to the second ring gear R 2 through the first shaft SH 1 is reversed by the second sun gear S 2 and is transmitted to the third sun gear S 3 through the fourth shaft SH 4 . Since the third ring gear R 3 is fixed by the first brake B 1 , the power transmitted to the third sun gear S 3 is decelerated by the third planet carrier C 3 and is transmitted to the fourth sun gear S 4 through the eighth shaft SH 8 . Since the fourth ring gear R 4 is fixed by the third brake B 3 , the power of the fourth sun gear S 4 is provided to the fifth ring gear R 5 through the sixth shaft SH 6 . Since the fifth sun gear S 5 is fixed by the first brake B 1 and the third clutch CL 3 , the power of the fifth ring gear R 5 is decelerated again and is drawn out to the output shaft OUT while forming the reverse state with the fifth planet carrier C 5 .

Meanwhile, the present referred to as described above may be expressed as follows.

That is, the present invention includes a first planetary gear set PG 1 , a second planetary gear set PG 2 , a third planetary gear set PG 3 , a fourth planetary gear set PG 4 , and a fifth planetary gear set PG 5 , each of which includes three rotation elements; six coupling elements configured to provide a frictional force variably; and nine shafts connected to the rotation elements of the planetary gear sets.

Here, the first shaft SH 1 is directly connected to the second rotation element of the first planetary gear set PG 1 , the third rotation element of the second planetary gear set PG 2 , and the input shaft IN, the second shaft SH 2 is directly connected to the second rotation element of the fifth planetary gear set PG 5 and the output shaft OUT, the third shaft SH 3 is directly connected to the third rotation element of the first planetary gear set PG 1 , the fourth shaft SH 4 is directly connected to the first rotation element of the second planetary gear set PG 2 and the first rotation element of the third planetary gear set PG 3 , the fifth shaft SH 5 is directly connected to the second rotation element of the second planetary gear set PG 2 and the first rotation element of the fifth planetary gear set PG 5 , the sixth shaft SH 6 is directly connected to the second rotation element of the fourth planetary gear set PG 4 and the third rotation element of the fifth planetary gear set PG 5 , and the remaining three shafts are fixedly secured to the transmission housing.

The three shafts, which are configured for being fixed to the transmission housing, include the seventh shaft SH 7 , the eighth shaft SH 8 , and the ninth shaft SH 9 . The seventh shaft SH 7 is directly connected to the first rotation element of the first planetary gear set PG 1 and the third rotation element of the third planetary gear set PG 3 , the eighth shaft SH 8 is directly connected to the second rotation element of the third planetary gear set PG 3 and the first rotation element of the fourth planetary gear set PG 4 , and the ninth shaft SH 9 is directly connected to the third rotation element of the fourth planetary gear set PG 4 .

In the case of the exemplary embodiment of FIG. 1 , among the six coupling elements, the first clutch CL 1 is disposed between the second shaft SH 2 and the third shaft SH 3 , the second clutch CL 2 is disposed between the first shaft SH 1 and the fifth shaft SH 5 , the third clutch CL 3 is disposed between the fifth shaft SH 5 and the seventh shaft SH 7 , the first brake B 1 is disposed between the seventh shaft SH 7 and the transmission housing HS, the second brake B 2 is disposed between the eighth shaft SH 8 and the transmission housing HS, and the third brake B 3 is disposed between the ninth shaft SH 9 and the transmission housing HS.

In the case of the exemplary embodiment of FIG. 3 , among the six coupling elements, the first clutch CL 1 is disposed between the second shaft SH 2 and the third shaft SH 3 , the second clutch CL 2 is disposed between the fourth shaft SH 4 and the fifth shaft SH 5 , the third clutch CL 3 is disposed between the fifth shaft SH 5 and the seventh shaft SH 7 , the first brake B 1 is disposed between the seventh shaft SH 7 and the transmission housing HS, the second brake B 2 is disposed between the eighth shaft SH 8 and the transmission housing HS, and the third brake B 3 is disposed between the ninth shaft SH 9 and the transmission housing HS.

The first to fifth planetary gear sets PG 1 to PG 5 are disposed in the axial direction of the input shaft IN and the output shaft OUT in the order of the first planetary gear set PG 1 , the second planetary gear set PG 2 , the third planetary gear set PG 3 , the fourth planetary gear set PG 4 , and the fifth planetary gear set PG 5 .

The rotation elements of each of the first to fifth planetary gear sets PG 1 to PG 5 are disposed in the order the first rotation element, the second rotation element, and the third rotation element from the rotation center toward the outside in the radial direction, in which the first rotation element is a sun gear of each planetary gear set, the second rotation element is a carrier, and the third rotation element is a ring gear.

As described above, with the configuration described above, the planetary gear train of an automatic transmission for a vehicle according to an exemplary embodiment of the present invention forms shifting stages of forward 10 speeds and 1 reverse speed and has a gear ratio span of 9.6. Thus, the fuel efficiency may be improved by making it possible to drive the engine mainly in a more efficient region.

In an exemplary embodiment of the present invention, the minimum inter-stage ratio is 1.137 or more, and the linearity of the inter-stage ratio changes with the shifting stage change is ensured to be similar to the ideal tendency of change of the inter-stage ratio, so that vehicle acceleration and rhythm of the engine speed before and after shifting may be improved, maximizing the driving performance of the vehicle.

For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “inner”, “outer”, “up”, “down”, “upper”, “lower”, “upwards”, “downwards”, “front”, “rear”, “back”, “inside”, “outside”, “inwardly”, “outwardly”, “internal”, “external”, “inner”, “outer”, “forwards”, and “backwards” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described to explain certain principles of the invention and their practical application, to enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.