Abstract:
The present disclosure relates to an automotive multistage transmission that includes four planetary gear sets and six shifting members, and each of the planetary gear sets include three rotary members selectively connected to the six shifting members to transmit torque between input and output shafts, preferably so that the automotive multistage transmission provides ten or more forward shifting stages and one or more rearward one shifting stages with few parts and a simple configuration. In this configuration, the transmission can improve fuel efficiency of a vehicle.

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2015-0019687, filed on Feb. 9, 2015, which is hereby incorporated by reference herein in its entirety. 
       FIELD 
       [0002]    The present disclosure relates to an automotive multistage transmission. 
       BACKGROUND 
       [0003]    The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
         [0004]    Recently, a rise in oil prices has caused manufacturers all over the world to rush into infinite competition. For engines in particular, manufacturers have been trying to reduce the weight and improve fuel efficiency through downsizing and similar measures. 
         [0005]    Alternatively, as a method capable of improving fuel efficiency through the transmission in a vehicle, there is a method of operating an engine at a more efficient operation point by increasing the shifting stages of the transmission, thereby improving fuel efficiency. 
         [0006]    Increasing the shifting stages of the transmission enables an engine to operate in a relatively lower range of RPM, so a vehicle can run more quietly. 
         [0007]    However, as the shifting stages of a transmission increase, the number of parts in the transmission increases, so the manufacturing cost, weight, and power transmission efficiency may become poor. 
       SUMMARY 
       [0008]    The present disclosure provides an automotive multistage transmission that can improve fuel efficiency of a vehicle as much as possible by operating an engine at the desired operation point and that can drive a vehicle more quietly by operating an engine more silently, by achieving ten or more forward shifting stages and one or more rearward shifting stages with fewer parts and a simpler configuration than in the conventional art. 
         [0009]    According to one aspect of the present disclosure, there is provided an automotive multistage transmission that includes: an input shaft and an output shaft; a first planetary gear set, a second planetary gear set, a third planetary gear set, and a fourth planetary gear set, each of the planetary gear sets including three rotary members and thus configured, structured and/or arranged for transmitting torque between the input shaft and the output shaft; and at least six shifting members connected to the rotary members of the planetary gear sets, in which in the first planetary gear set, a first rotary member stays connected to a third rotary member of the second planetary gear set and is selectively fixable to any one of the shifting members, a second rotary member stays connected to a third rotary member of the third planetary gear set, and a third rotary member is selectively fixable to another one of the shifting members, in the second planetary gear set, a first rotary member is variably connected to a second rotary member of the third planetary gear set and a first rotary member of the fourth planetary gear set, a second rotary member stays connected to the input shaft and is variably connected to the first rotary member of the fourth planetary gear set, and the third rotary member stays connected to a first rotary member of the third planetary gear set, the third rotary member of the third planetary gear set stays connected to a second rotary member of the fourth planetary gear set, and a third rotary member of the fourth planetary gear set stays connected to the output shaft. 
         [0010]    According to another aspect of the present disclosure, there is provided an automotive multistage transmission that includes: a first planetary gear set, a second planetary gear set, a third planetary gear set, and a fourth planetary gear set each including three rotary members; six shifting members variably providing a friction force; and eight rotary shafts connected to the rotary members of the planetary gear sets, in which a first rotary shaft is an input shaft directly connected to a second rotary member of the second planetary gear set, a second rotary shaft is directly connected to a first rotary member of the first planetary gear set, a third rotary member of the second planetary gear set, and a first rotary member of the third planetary gear set, a third rotary shaft is directly connected to a third rotary member of the first planetary gear set, a fourth rotary shaft is directly connected to a second rotary member of the first planetary gear set, a third rotary member of the third planetary gear set, and a second rotary member of the fourth planetary gear set; a fifth rotary shaft is directly connected to a first rotary member of the secondary planetary gear set, a sixth rotary shaft is directly connected to a second rotary member of the third planetary gear set, a seventh rotary shaft is directly connected to a first rotary member of the fourth planetary gear set, and an eighth rotary shaft is an output shaft directly connected to a third rotary member of the fourth planetary gear set; and in which, in the six shifting members, a first clutch is disposed between the first rotary shaft and the seventh rotary shaft, a second clutch is disposed between the fourth rotary shaft and the eighth rotary shaft, a third clutch is disposed between the second rotary shaft and a transmission case, a fourth clutch is disposed between the third rotary shaft and the transmission case, a fifth clutch is disposed between the fifth rotary shaft and the sixth rotary shaft, and a sixth clutch is disposed between the fifth rotary shaft and the seventh rotary shaft. 
         [0011]    According to a further aspect of the present disclosure, there is provided an automotive multistage transmission that includes: a first planetary gear set, a second planetary gear set, a third planetary gear set, and a fourth planetary gear set each including three rotary members; six shifting members variably providing a friction force; and eight rotary shafts connected to the rotary members of the planetary gear sets, in which a first rotary shaft is an input shaft directly connected to a second rotary member of the second planetary gear set, a second rotary shaft is directly connected to a first rotary member of the first planetary gear set, a third rotary member of the second planetary gear set, and a first rotary member of the third planetary gear set, a third rotary shaft is directly connected to a third rotary member of the first planetary gear set, a fourth rotary shaft is directly connected to a second rotary member of the first planetary gear set, a third rotary member of the third planetary gear set, and a second rotary member of the fourth planetary gear set; a fifth rotary shaft is directly connected to a first rotary member of the secondary planetary gear set, a sixth rotary shaft is directly connected to a second rotary member of the third planetary gear set, a seventh rotary shaft is directly connected to a first rotary member of the fourth planetary gear set, and an eighth rotary shaft is an output shaft directly connected to a third rotary member of the fourth planetary gear set; and in which, in the six shifting members, a first clutch is disposed between the first rotary shaft and the seventh rotary shaft, a second clutch is disposed between the seventh rotary shaft and the eighth rotary shaft, a third clutch is disposed between the second rotary shaft and a transmission case, a fourth clutch is disposed between the third rotary shaft and the transmission case, a fifth clutch is disposed between the fifth rotary shaft and the sixth rotary shaft, and a sixth clutch is disposed between the fifth rotary shaft and the seventh rotary shaft. 
         [0012]    According to still another aspect of the present disclosure, there is provided an automotive multistage transmission that includes: a first planetary gear set, a second planetary gear set, a third planetary gear set, and a fourth planetary gear set each including three rotary members; six shifting members variably providing a friction force; and eight rotary shafts connected to the rotary members of the planetary gear sets, in which a first rotary shaft is an input shaft directly connected to a second rotary member of the second planetary gear set, a second rotary shaft is directly connected to a first rotary member of the first planetary gear set, a third rotary member of the second planetary gear set, and a first rotary member of the third planetary gear set, a third rotary shaft is directly connected to a third rotary member of the first planetary gear set, a fourth rotary shaft is directly connected to a second rotary member of the first planetary gear set, a third rotary member of the third planetary gear set, and a second rotary member of the fourth planetary gear set; a fifth rotary shaft is directly connected to a first rotary member of the secondary planetary gear set, a sixth rotary shaft is directly connected to a second rotary member of the third planetary gear set, a seventh rotary shaft is directly connected to a first rotary member of the fourth planetary gear set, and an eighth rotary shaft is an output shaft directly connected to a third rotary member of the fourth planetary gear set; and in which, in the six shifting members, a first clutch is disposed between the first rotary shaft and the seventh rotary shaft, a second clutch is disposed between the fourth rotary shaft and the seventh rotary shaft, a third clutch is disposed between the second rotary shaft and a transmission case, a fourth clutch is disposed between the third rotary shaft and the transmission case, a fifth clutch is disposed between the fifth rotary shaft and the sixth rotary shaft, and a sixth clutch is disposed between the fifth rotary shaft and the seventh rotary shaft. 
         [0013]    According to the present disclosure, it is possible to improve fuel efficiency of a vehicle as much as possible by operating an engine at a desired operation point and that can drive a vehicle more quietly by operating an engine more silently, by achieving ten or more forward shifting stages and one or more rearward one shifting stages with fewer parts and a simpler configuration than in the conventional art. 
         [0014]    Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0015]    In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which: 
           [0016]      FIG. 1  is a diagram showing the configuration of an automotive multistage transmission according to a first form of the present disclosure; 
           [0017]      FIG. 2  is a table showing operation modes of the transmission shown in  FIG. 1 ; 
           [0018]      FIG. 3  is a diagram showing the configuration of an automotive multistage transmission according to a second form of the present disclosure; 
           [0019]      FIG. 4  is a table showing operation modes of the transmission shown in  FIG. 3 ; 
           [0020]      FIG. 5  is a diagram showing the configuration of an automotive multistage transmission according to a third form of the present disclosure; and 
           [0021]      FIG. 6  is a table showing operation modes of the transmission shown in  FIG. 5 . 
       
    
    
       [0022]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
       DETAILED DESCRIPTION 
       [0023]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
         [0024]    Referring to  FIGS. 1, 3, and 5 , forms of the present disclosure, in common, include: an input shaft “IN” and an output shaft “OUT”; a first planetary gear set “PG 1 ”, a second planetary gear set “PG 2 ,” a third planetary gear set “PG 3 ,” and a fourth planetary gear set “PG 4 ,” each of the planetary gear sets including three rotary members, transmitting torque between the input shaft “IN” and the output shaft “OUT”; and at least six shifting members (e.g. clutches CL 1 -CL 6 ) connected to the rotary members of the planetary gear sets. 
         [0025]    As for the first planetary gear set PG 1 , a first rotary member S 1  stays connected (e.g. is permanently engaged) to a third rotary member R 2  of the second planetary gear set PG 2  and is fixable to any one of the shifting members, a second rotary member C 1  stays connected to a third rotary member R 3  of the third planetary gear set PG 3 , and a third rotary member R 1  is fixable to another one of the shifting members. 
         [0026]    As for the second planetary gear set PG 2 , a first rotary member S 2  is variably connected (e.g. selectively, intermittently connected) to a second rotary member C 3  of the third planetary gear set PG 3  and a first rotary member S 4  of the fourth planetary gear set PG 4 , a second rotary member C 2  stays connected to the input shaft IN and is variably connected to the first rotary member S 4  of the fourth planetary gear set PG 4 , and the third rotary member R 2  stays connected to a first rotary member S 3  of the third planetary gear set PG 3 . 
         [0027]    The third rotary member R 3  of the third planetary gear set PG 3  stays connected to a second rotary member C 4  of the fourth planetary gear set PG 4 , and a third rotary member R 4  of the fourth planetary gear set PG 4  stays connected to the output shaft OUT. 
         [0028]    The first planetary gear set PG 1 , second planetary gear set PG 2 , third planetary gear set PG 3 , and fourth planetary gear set PG 4  are sequentially arranged in the axial direction of the input shaft IN and the output shaft OUT. 
         [0029]    The first rotary member S 1  of the first planetary gear set PG 1  is fixable to a transmission case CS by a third clutch CL 3  of the shifting members and the third rotary member R 1  of the first planetary gear set PG 1  is fixable to the transmission case CS by a fourth clutch CL 4  of the shifting members. 
         [0030]    Accordingly, the third clutch CL 3  and the fourth clutch CL 4  can function as a brake, thereby restricting or allowing rotation of the first rotary member S 1  and the third rotary member R 1  of the first planetary gear set PG 1 . 
         [0031]    The others of the shifting members form variable connection structures between the rotary members of the planetary gear sets. 
         [0032]    That is, a first clutch CL 1  of the shifting members forms a variable connection structure between the second rotary member C 2  of the second planetary gear set PG 2  and the first rotary member S 4  of the fourth planetary gear set PG 4 , a fifth clutch CL 5  of the shifting members forms a variable connection structure between the first rotary member S 2  of the second planetary gear set PG 2  and the second rotary member C 3  of the third planetary gear set PG 3 , and a sixth clutch CL 6  of the shifting members forms a variable connection structure between the first rotary member S 2  of the second planetary gear set PG 2  and the first rotary member S 4  of the fourth planetary gear set PG 4 . 
         [0033]    This configuration is applied in common to a first form, a second form, and a third form of the present disclosure, and the differences between the forms of the present disclosure are described below. 
         [0034]    In the first form shown in  FIG. 1 , the third rotary member R 3  of the third planetary gear set PG 3  and the third rotary member R 4  of the fourth planetary gear set PG 4  are variably connected, and the second clutch CL 2  forms a variable connection structure between the third rotary member R 3  of the third planetary gear set PG 3  and the third rotary member R 4  of the fourth planetary gear set PG 4 . 
         [0035]    In the second form shown in  FIG. 3 , the first rotary member S 4  and the third rotary member R 4  of the fourth planetary gear set PG 4  are variably connected, and the second clutch CL 2  forms a variable connection structure between the first rotary member S 4  and the third rotary member R 4  of the fourth planetary gear set PG 4 . 
         [0036]    Further, in the third form shown in  FIG. 5 , the first rotary member S 4  and the second rotary member C 4  of the fourth planetary gear set PG 4  are variably connected, and the second clutch CL 2  forms a variable connection structure between the first rotary member S 4  and the second rotary member C 4  of the fourth planetary gear set PG 4 . 
         [0037]    As a result, the first to third forms are structurally different in light of the position of the second clutch CL 2 . 
         [0038]    In the forms shown in  FIGS. 1, 3 and 5 , the first rotary member S 1 , the second rotary member C 1 , and the third rotary member R 1  of the first planetary gear set PG 1  are a first sun gear, a first carrier, and a first ring gear, respectively; the first rotary member S 2 , the second rotary member C 2 , and the third rotary member R 2  of the second planetary gear set PG 2  are a second sun gear, a second carrier, and a second ring gear, respectively; the first rotary member S 3 , the second rotary member C 3 , and the third rotary member R 3  of the third planetary gear set PG 3  are a third sun gear, a third carrier, and a third ring gear, respectively; and the first rotary member S 4 , the second rotary member C 4 , and the third rotary member R 4  of the fourth planetary gear set PG 4  are a fourth sun gear, a fourth carrier, and a fourth ring gear, respectively. 
         [0039]    Automotive multistage transmissions having these configurations may be expressed as follows. 
         [0040]    The first to third forms, in common, include: the first planetary gear set PG 1 , the second planetary gear set PG 2 , the third planetary gear set PG 3 , and the fourth planetary gear set PG 4 , each of the planetary gear sets including three rotary members, the six shifting members variably providing a friction force; and eight rotary shafts connected to the rotary members of the planetary gear sets. 
         [0041]    In those forms, a first rotary shaft RS 1  is an input shaft IN directly connected to the second rotary member C 2  of the second planetary gear set PG 2 ; a second rotary shaft RS 2  is directly connected to the first rotary member S 1  of the first planetary gear set PG 1  and also connected to the third rotary member R 2  of the second planetary gear set PG 2  and the first rotary member S 3  of the third planetary gear set PG 3 ; a third rotary shaft RS 3  is directly connected to the third rotary member R 1  of the first planetary gear set PG 1 ; a fourth rotary shaft RS 4  connecting the second rotary member C 1  of the first planetary gear set PG 1  to the third rotary member R 3  of the third planetary gear set PG 3  and the second rotary member C 4  of the fourth planetary gear set PG 4 ; a fifth rotary shaft RS 5  is directly connected to the first rotary member S 2  of the secondary planetary gear set PG 2 ; a sixth rotary shaft RS 6  is directly connected to the second rotary member C 3  of the third planetary gear set PG 3 ; a seventh rotary shaft RS 7  is directly connected to the first rotary member S 4  of the fourth planetary gear set PG 4 ; and an eighth rotary shaft RS 8  is an output shaft OUT directly connected to the third rotary member R 4  of the fourth planetary gear set PG 4 . 
         [0042]    Further, in the six shifting members, the first clutch CL 1  is disposed between the first rotary shaft RS 1  and the seventh rotary shaft RS 7 , the third clutch CL 3  is disposed between the second rotary shaft RS 2  and the transmission case CS, the fourth clutch CL 4  is disposed between the third rotary shaft RS 3  and the transmission case CS, the fifth clutch CL 5  is disposed between the fifth rotary shaft RS 5  and the sixth rotary shaft RS 6 , and the sixth clutch CL 6  is disposed between the fifth rotary shaft RS 5  and the seventh rotary shaft RS 7 . 
         [0043]    These configurations described above are the same in all the first to third forms, but there is a difference in the position of the second clutch CL 2 . The second clutch CL 2  is disposed between the fourth rotary shaft RS 4  and the eighth rotary shaft RS 8  in the first form, between the seventh rotary shaft RS 7  and the eighth rotary shaft RS 8  in the second form, and between the fourth rotary shaft RS 4  and the seventh rotary shaft RS 7  in the third form. 
         [0044]    The forms of an automotive multistage transmission of the present disclosure, which include four single planetary gear sets and six shifting members, achieve ten forward shifting stages and one rearward shifting stage in accordance with the operation mode tables, as shown in  FIGS. 2, 4, and 6 , respectively. That is, they can achieve the ten shifting stages with relatively fewer parts and simpler configurations than in the conventional art. Therefore, it is possible to contribute to contribute to quiet driving and improvement of fuel efficiency of a vehicle, resulting in improvement of the commercial value of the vehicle. 
         [0045]    Although the present disclosure was described with reference to specific forms shown in the drawings, it is apparent to those skilled in the art that the present disclosure may be changed and modified in various ways without departing from the scope of the present disclosure.