JP2015068409A - Automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve an 8-forward speed automatic transmission in which direct coupling gears can be set to 6-speed gears, gear steps between shift stages can be distributed appropriately, and an input shaft can be shortened.SOLUTION: An automatic transmission includes: an input shaft 12 and an output shaft 13 located coaxially with each other; single pinion type first and fourth gear sets PG1 and PG4; double pinion type second and third gear sets PG2 and PG3; first to third clutches CL1 to CL3 for disengaging and engaging between predetermined rotary elements of the gear sets; and first and second brakes BR1 and BR2 for disengaging and engaging the predetermined rotary elements of the gear sets and a transmission case 11. When the first to third clutches CL1 to CL3 are engaged and the first and second brakes BR1 and BR2 are released, a 6-speed gear whose reduction gear ratio 1 is formed, and the first and second gear sets PG1 and PG2 each having a first carrier C1 and a second sun gear S2 always coupled with the input shaft 12 are located on a driving source side in the axial direction closer than the other gear sets PG3 and PG4.

Description

  The present invention relates to an automatic transmission mounted on a vehicle, and belongs to the technical field of a vehicle transmission.

  An automatic transmission mounted on a vehicle generally includes a plurality of planetary gear sets (planetary gear mechanisms) and a plurality of hydraulic friction engagement elements such as clutches and brakes, and these friction engagement elements are selectively controlled by hydraulic control. By being fastened, the power transmission path through each planetary gear set is switched so that a plurality of forward shift speeds and typically one reverse speed speed can be realized.

  For example, Patent Document 1 includes three single-pinion type planetary gear sets and five frictional engagement elements, and by fastening any two of these frictional engagement elements, six forward stages An automatic transmission that realizes one reverse speed is disclosed.

  On the other hand, in recent years, in order to improve the fuel efficiency performance and the speed change performance of the engine, it is required to further increase the forward shift speed. For example, if three planetary gear sets and six friction engagement elements are provided, The forward eight stages can be realized by a combination of fastening of two friction fastening elements among these friction fastening elements.

  However, in this configuration, there are four non-engaged frictional engagement elements at each gear position. Therefore, the sliding resistance between the friction plates in these frictional engagement elements or the viscosity of the lubricating oil between the friction plates. Due to the resistance or the like, the driving loss of the entire transmission increases, and there is a possibility that the effect of improving the fuel consumption performance due to the multi-stage is impaired.

  On the other hand, Patent Document 2 includes two single pinion type planetary gear sets and two double pinion type planetary gear sets, and five friction engagement elements, and selectively selects three of these friction engagement elements. An automatic transmission that achieves eight forward speeds by engaging is disclosed.

  According to this, since the number of friction engagement elements in the non-engaged state at each shift stage is two, the drive loss as described above is suppressed.

JP 2008-298126 A JP 2009-174626 A

  However, in the configuration of the automatic transmission disclosed in Patent Document 2, the direct connection stage with a reduction ratio of 1 is 5 speeds, the reduction stage is 4 stages, and the speed increasing stage is 3 stages, and the reduction ratio is overall. Therefore, there is a concern that the driving force is insufficient when an engine having a small displacement relative to the vehicle weight is mounted. In particular, since the start acceleration performance may be insufficient, the automatic transmission has a large reduction gear ratio for the first gear. For this reason, the gear step between the first and second gears (lower gear ratio / upper gear ratio) The reduction ratio) is larger than the gear steps between the other gears, and appropriate gear step distribution is sacrificed (see the comparative example in FIG. 14).

  To solve this problem, it is conceivable to secure a required driving force and start acceleration while realizing an appropriate gear step distribution by increasing the final reduction ratio.

  However, in this case, the input gear of the differential mechanism is enlarged, and in particular, in the case of a front engine / front drive vehicle or the like in which the transmission is a horizontal type and a drive unit integrated with the differential mechanism is configured. The size of the unit increases, and mounting in the engine room becomes a problem.

  Further, in the automatic transmission disclosed in Patent Document 2, it may be considered that the direct coupling stage is set to a high gear stage of 6 speeds or more, but three of the five frictional engagement elements are fastened. Of the 10 combinations, the remaining one combination that is not used at the 1st to 8th speeds and the reverse speed, specifically, the clutches C1 and the brakes B1 and B2, the clutches Ca and Cb are released. Therefore, the carrier Cr in the planetary gear set 8 becomes free, so that no rotational force can be output to the ring gear Rr of the planetary gear set 8 to which the output gear 3 is connected, resulting in a neutral state.

  In other words, in the automatic transmission disclosed in Patent Document 2, it is impossible to provide a new shift stage on the lower speed side than the fifth speed and to make the direct connection stage higher than the sixth speed.

  Also, in this automatic transmission, it is intended to change the connection relationship between the rotating elements of each planetary gear set and the relationship between these rotating elements and the frictional engagement elements in an attempt to set the direct gear to 6th speed or more. However, in general, in the configuration of an automatic transmission, when some changes are made to other parts, and it is possible to realize an appropriate reduction ratio of each shift stage and an appropriate gear step between the shift stages, with a realizable gear size. After all, a new automatic transmission must be created from the beginning.

  In that case, in order to reduce the inertia mass on the input side of the speed change mechanism and to shorten the inertia phase period during the speed change operation, the layout of the components that speed up the speed change operation is performed. It is required to lay out the components so that the increase in the input shaft size accompanying the multi-stage is suppressed.

  In the present invention, in view of the above-described actual situation regarding the multi-stage automatic transmission, the direct-coupled speed can be set to 6th speed, the gear step can be appropriately distributed between the speeds, and the input shaft can be shortened. The realization of an automatic transmission with eight forward speeds that can be achieved has been realized as a result of intensive studies.

  In order to solve the above-described problems, an automatic transmission according to the present invention is configured as follows.

First, the invention according to claim 1 of the present application is
In the transmission case,
An input shaft coupled to the drive source;
An output member disposed coaxially with the input shaft and coupled to a differential mechanism;
A single pinion type first planetary gear set having a first sun gear, a first carrier and a first ring gear;
A double pinion type second planetary gear set having a second sun gear, a second carrier, and a second ring gear;
A double pinion type third planetary gear set having a third sun gear, a third carrier, and a third ring gear;
A single pinion type fourth planetary gear set having a fourth sun gear, a fourth carrier, and a fourth ring gear;
First, second and third clutches;
First and second brakes;
An automatic transmission with
The input shaft, the first carrier, and the second sun gear are always connected,
The output member, the first ring gear and the third ring gear are always connected,
The third sun gear and the fourth ring gear are always connected,
The second ring gear and the fourth carrier are always connected,
The first clutch connects and disconnects the second carrier and the fourth sun gear;
The second clutch connects and disconnects the first sun gear and the fourth sun gear;
The third clutch connects and disconnects the fourth sun gear and the fourth ring gear;
The first brake connects and disconnects the second carrier and the transmission case,
The second brake connects and disconnects the third carrier and the transmission case;
When the first, second, and third clutches are engaged and the first and second brakes are released, a sixth speed with a reduction ratio of 1 is formed, and
The first and second planetary gear sets each having a first carrier and a second sun gear, to which the input shaft is always connected, are arranged closer to the drive source side in the axial direction than the other planetary gear sets. .

The invention according to claim 2 is the invention according to claim 1,
Of the first, second and third clutches and the first and second brakes,
First speed is formed when the third clutch, the first brake and the second brake are engaged,
Second speed is formed when the first clutch, the first brake and the second brake are engaged,
Third speed is formed when the first clutch, the third clutch and the second brake are engaged,
When the first clutch, the second clutch, and the second brake are engaged, the fourth speed is formed,
When the second clutch, the third clutch and the second brake are engaged, the fifth speed is formed,
Seventh speed is formed when the second clutch, the third clutch and the first brake are engaged,
8-speed is formed when the first clutch, the second clutch and the first brake are engaged,
A reverse speed is formed when the second clutch, the first brake, and the second brake are engaged.

  With the above configuration, according to the first aspect of the present invention, the forward 8-speed automatic transmission including two double pinion type planetary gear sets, two single pinion type planetary gear sets, and five frictional engagement elements. In this machine, it is possible to set the direct connection stage to 6-speed, and the number of reduction stages is larger than that of the automatic transmission in which the above-mentioned direct connection stage is 5-speed.

  Therefore, the overall reduction ratio can be increased, and when applied to a small displacement engine, the final reduction ratio increases, the drive unit increases in size, and the mountability in the engine room deteriorates. It is possible to achieve the required driving force and start acceleration while suppressing the above and the like and making it possible to set an appropriate gear step between the respective gears.

  In particular, according to the present invention, the first and second planetary gear sets having rotating elements whose input shafts are always connected are arranged closer to the drive source side than the other planetary gear sets, so the planetary gear sets are arranged in a different order. Compared to the case, the input shaft can be shortened. As a result, the inertial mass on the input side is reduced, so that the inertia phase period during the shift operation can be shortened, and a quick shift operation can be realized.

  Furthermore, according to the invention described in claim 2, by appropriately setting the number of teeth of the sun gear and the ring gear of each planetary gear set, it is possible to appropriately reduce the 1st to 5th speeds, 7th and 8th speeds, and the reverse speed. The ratio is realized.

1 is a skeleton diagram of an automatic transmission according to an embodiment of the present invention. 3 is a fastening table of frictional engagement elements of the automatic transmission. FIG. 4 is a skeleton diagram and a reduction ratio diagram illustrating a fastening state of a frictional engagement element at the first speed. FIG. 4 is a skeleton diagram and a reduction ratio diagram illustrating a fastening state of a frictional engagement element at the second speed. FIG. 4 is a skeleton diagram and a reduction ratio diagram showing a fastening state of a frictional engagement element at the third speed. FIG. 4 is a skeleton diagram and a reduction ratio diagram illustrating a fastening state of a frictional engagement element at the fourth speed. FIG. 6 is a skeleton diagram and a reduction ratio diagram illustrating a fastening state of a frictional engagement element at the fifth speed. FIG. 6 is a skeleton diagram and a reduction ratio diagram illustrating a fastening state of a frictional engagement element at the sixth speed. FIG. 6 is a skeleton diagram and a reduction ratio diagram illustrating a fastening state of a frictional engagement element at the seventh speed. FIG. 7 is a skeleton diagram and a reduction ratio diagram illustrating a fastening state of a frictional engagement element at the eighth speed. FIG. 4 is a skeleton diagram and a reduction ratio diagram illustrating a fastening state of a frictional engagement element at a reverse speed. It is a table | surface of the example of the number of teeth of the gear which comprises a planetary gear set. It is a table | surface which shows the reduction ratio and gear step in the case of the number of teeth example of FIG. It is the graph which illustrated the gear step of FIG. 13 with the comparative example. FIG. 2 is a skeleton diagram according to a modification of the automatic transmission shown in FIG. 1.

  Embodiments of the present invention will be described below.

  FIG. 1 is a skeleton diagram showing a configuration of an automatic transmission 10 according to an embodiment of the present invention. The automatic transmission 10 is arranged in a transmission case 11 on the same axis line. And an output shaft 13, and a single pinion type first planetary gear set (hereinafter simply referred to as a “first gear set”) PG 1 from the input side (drive source side) on the right side of the drawing on these axes. Double pinion type second planetary gear set (hereinafter simply referred to as “second gear set”) PG2, double pinion type third planetary gear set (hereinafter simply referred to as “third gear set”) PG3, and single pinion type fourth planetary gear set A planetary gear set (hereinafter simply referred to as “fourth gear set”) PG4 is disposed.

  Further, a first clutch CL1 and a second clutch CL2 are disposed between the second gear set PG2 and the third gear set PG3 from the input side, and a third gear set PG3 and a fourth gear set PG4 are provided between the third gear set PG3 and the fourth gear set PG4. A clutch CL3 is provided. The first brake BR1 is disposed on the input side of the second gear set PG2, and the second brake BR2 is disposed on the output side of the fourth gear set PG4.

  Each of the first to fourth gear sets PG1 to PG4 has three rotating elements. As these rotating elements, the first gear set PG1 has a first sun gear S1, a first ring gear R1, and a first carrier C1. The second gear set PG2 has a second sun gear S2, a second ring gear R2, and a second carrier C2, and the third gear set PG3 has a third sun gear S3, a third ring gear R3, and a third carrier C3, The four gear set PG4 includes a fourth sun gear S4, a fourth ring gear R4, and a fourth carrier C4.

  Here, the first and fourth gear sets PG1 and PG4 of the single pinion type have pinions meshed with the first and fourth sun gears S1 and S4 and the first and fourth ring gears R1 and R4, respectively. Pinions are supported on the first and fourth carriers C2 and C4, respectively. The double pinion type second and third gear sets PG2 and PG3 include a first pinion meshed with the second and third sun gears S2 and S3, and the first and second pinion and second and third ring gears R2 and R3, respectively. The second and third carriers C2 and C3 are respectively supported by the second and third carriers C2 and C3.

  In the automatic transmission 10, the third sun gear S3 and the fourth ring gear R4, the first ring gear R1 and the third ring gear R3, the first carrier C1 and the second sun gear S2, and the second ring gear R2 are used. And the fourth carrier C4 are always connected. The input shaft 12 is always connected to the first carrier C1 and the second sun gear S2, and the output shaft 13 is always connected to the first ring gear R1 and the third ring gear R3.

  The first clutch CL1 is disposed between the second carrier C2 and the fourth sun gear S4 so as to connect and disconnect them, and the second clutch CL2 is connected to the first sun gear S1 and the first sun gear S1. Between the fourth sun gear S4 and the fourth ring gear R4. The third clutch CL3 is disposed between the fourth sun gear S4 and the fourth ring gear R4. It is designed to connect and disconnect.

  Further, the first brake BR1 is disposed between the transmission case 11 and the second carrier C2, and connects and disconnects them. The second brake BR2 is connected to the transmission case 11. And the third carrier C3 to connect and disconnect them.

  According to the automatic transmission 10, in the above configuration, as shown in the fastening table of FIG. 2, by selectively fastening three friction fastening elements from five friction fastening elements, the forward 1 to 8 speed And a reverse speed is formed.

  Next, the mechanism by which the reduction ratio is determined for each gear according to the combination of fastening of the frictional engagement elements shown in FIG. 2 will be described with reference to FIGS.

  FIGS. 3 to 11 (a) show the frictional engagement elements that are fastened at the gears by shading, and FIG. 3 (b) shows the reduction ratios of the gears. As shown in the figure, in this reduction ratio diagram, the lateral spacing between the rotating elements in each of the gear sets PG1 to PG4 is determined by the respective gear ratios. In the single pinion type gear sets PG1 and PG4, the ring gear, carrier, sun gear In the double pinion type gear sets PG2 and PG3, the carrier, the ring gear, and the sun gear are arranged in this order.

  The vertical axis represents the rotational speed. The input rotational speed, that is, the rotational speed of the first carrier C1 and the second sun gear S2 always connected to the input shaft 12 is "1", and the rotational element fixed by the brake. Is set to “0”. Further, the rotational speeds of the rotational elements that are always connected and the rotational elements that are connected by the clutch are equal. N1 to N8 and Nr indicate the rotational speeds at the respective gear speeds of rotation output from the first and third ring gears R1 and R3 to the output shaft 13, and the reciprocal of the output rotational speed is a deceleration at the gear speed. It becomes a ratio.

  First, at the first speed, as shown in FIG. 3, since the third clutch CL3 and the first and second brakes BR1 and BR2 are engaged, the rotational speeds of the second carrier C2 and the third carrier C3 are “0”. , The fourth sun gear S4 and the fourth ring gear R4 are combined and the fourth gear set PG4 is integrated, so that the rotating elements of the fourth gear set PG4 rotate the same and are always connected to the fourth carrier C4. The third sun gear S3 always connected to the second ring gear R2 and the fourth ring gear R4 that have been rotated also rotates in the same manner.

  The rotational speeds of these rotational elements are determined in the second gear set PG2 from the condition that the rotational speed of the second sun gear S2 is "1" and the rotational speed of the second carrier C2 is "0". By inputting to the third sun gear S3 of the gear set PG3, the rotational speed of the third ring gear R3 is determined, and this becomes the output rotational speed N1.

  Next, at the second speed, as shown in FIG. 4, since the first clutch CL1 and the first and second brakes BR1 and BR2 are engaged, the rotational speeds of the second carrier C2 and the third carrier C3 are “ 0 "and the second carrier C2 and the fourth sun gear S4 are connected to each other so that the rotation of the fourth sun gear S4 is also" 0 ".

  Since the rotation of the second sun gear S2 is “1” and the rotation of the second carrier C2 is “0”, the rotational speed of the second ring gear R2 and the fourth carrier C4 always connected thereto is determined. Thus, the rotational speed of the fourth ring gear R4 and the rotational speed of the third sun gear S3 always connected to the fourth ring gear R4 are determined. As a result, in the third gear set PG3, since the rotation speed of the third carrier C3 is “0”, the rotation speed of the third ring gear R3 is determined and becomes the output rotation speed N2.

  Next, at the third speed, as shown in FIG. 5, since the first and third clutches CL1 and CL3 and the second brake BR2 are engaged, first, the fourth sun gear S4 and the fourth ring gear R4 are coupled. As a result of the integration of the fourth gear set PG4, the rotating elements of the fourth gear set PG4 rotate the same, and the second ring gear R2 always connected to the fourth carrier C4 and the first ring gear R4 always connected to the fourth ring gear R4. The 3 sun gear S3 also rotates in the same manner.

  Further, the fourth sun gear S4 and the second carrier C2 are connected, so that the second gear set PG2 is also integrated. As a result, the entire second and fourth gear sets PG2, PG42 are input to the second sun gear S2. It rotates together with the input rotation speed “1”.

  Then, this rotational speed “1” is transmitted to the third sun gear S3 of the third gear set PG3 in which the rotational speed of the third carrier C3 is “0”, thereby determining the rotational speed of the third ring gear R3, This is the output rotation speed N3.

  Next, at the fourth speed, as shown in FIG. 6, since the first and second clutches CL1 and CL2 and the second brake BR2 are engaged, the rotational speed of the third carrier C3 becomes “0”. The first sun gear S1, the second carrier C2, and the fourth sun gear S4 are connected and rotate in the same direction.

  And these conditions, 3rd sun gear S3 and 4th ring gear R4 are always connected, 2nd ring gear R2 and 4th carrier C4 are always connected, The 1st carrier C1 and 2nd sun gear which are input rotation elements From the condition that S2 is always connected and the first ring gear R1 and the third ring gear R3, which are output rotating elements, are always connected, the input rotational speed “1” to the first carrier C1 and the second sun gear S2 is “1”. The rotation speeds of the first ring gear R1 and the third ring gear R3 with respect to "" are determined, and this becomes the output rotation speed N4.

  Next, at the fifth speed, as shown in FIG. 7, since the second and third clutches CL2 and CL3 and the second brake BR2 are engaged, first, the fourth sun gear S4 and the fourth ring gear R4 are coupled. As a result of the integration of the fourth gear set PG4, the rotating elements of the fourth gear set PG4 rotate the same and are connected to the third sun gear S3 and the fourth sun gear S4 that are always connected to the fourth ring gear R4. The first sun gear S1 also rotates in the same way.

  As a result, in the first gear set PG1 and the third gear set PG3, the first sun gear S1 and the third sun gear S3 rotate the same, and the always connected first ring gear R1 and third ring gear R3 rotate the same, Further, from the condition that the rotation speed of the third carrier C3 is “0”, the rotation speeds of the first ring gear R1 and the third ring gear R3, which are output rotation elements, are determined, and this rotation speed is the output rotation speed N5. Become.

  Next, at the sixth speed, as shown in FIG. 8, the first, second, and third clutches CL1, CL2, and CL3 are engaged. Therefore, first, the fourth sun gear S4 and the fourth ring gear R4 are coupled. When the fourth gear set PG4 is integrated, the rotating elements of the fourth gear set PG4 rotate the same, and the second ring gear R2 always connected to the fourth carrier C4 and the third sun gear always connected to the fourth ring gear R4. S3 also rotates in the same manner, and the first sun gear S1 connected to the fourth sun gear S4 also rotates in the same direction.

  Further, since the fourth sun gear S4 and the second carrier C2 are connected, the second gear set PG2 is also integrated, and each rotating element of the second gear set rotates the same, and the second sun gear S2 is always connected to the second sun gear S2. The first carrier C1 also rotates in the same direction. As a result, the first gear set PG1 is also integrated, and the first ring gear R1 and the third ring gear R3 that is always connected to the first gear set PG1 rotate in the same direction as the rotation elements. As a result, the third gear set PG3 is also integrated, the first to fourth gear sets PG1 to PG4 are all integrated, and all the rotating elements rotate at the same rotational speed.

  Therefore, the rotational speed “1” input to the first carrier C1 and the second sun gear S2 is output as it is as the output rotational speed N6 from the first and third ring gears R1 and R3. As a result, the sixth speed becomes a direct coupling stage with a reduction ratio of “1”.

  Next, at the seventh speed, as shown in FIG. 9, since the second and third clutches CL2 and CL3 and the first brake BR1 are engaged, first, the fourth sun gear S4 and the fourth ring gear R4 are coupled. Since the fourth gear set PG4 is integrated, the rotating elements of the fourth gear set PG4 rotate the same, and the second ring gear R2 always connected to the fourth carrier C4 and the first ring gear R4 always connected to the fourth ring gear R4. The third sun gear S3 also rotates in the same manner, and the first sun gear S1 connected to the fourth sun gear S4 also rotates in the same direction.

  Since these conditions and the rotation speed of the second carrier C2 are “0” and the rotation speeds of the first carrier C1 and the second sun gear S2 are “1”, the rotation of each of the rotating elements rotating the same is performed. Along with this, the rotational speed of the first ring gear R1 is determined, and this rotational speed becomes the output rotational speed N7.

  Next, at the 8th speed, as shown in FIG. 10, since the first and second clutches CL1 and CL2 and the first brake BR1 are engaged, the rotational speed of the second carrier C2 is set to “0”. At the same time, the rotational speeds of the first sun gear S1 and the fourth sun gear S4 connected thereto are also “0”.

  In the first gear set PG1, when the rotation speed of the first carrier C1 is “1” and the rotation speed of the first sun gear S1 is “0”, the rotation of the first ring gear R1 is determined. The output rotation speed N8 is obtained.

  Further, at the reverse speed, as shown in FIG. 11, since the second clutch CL2 and the first and second brakes BR1 and BR2 are engaged, the first sun gear S1 and the fourth sun gear S4 are connected, As these rotate the same, the rotation speeds of the second and third carriers C2 and C3 become “0”.

  And these conditions, 3rd sun gear S3 and 4th ring gear R4 are always connected, 2nd ring gear R2 and 4th carrier C4 are always connected, The 1st carrier C1 and 2nd sun gear which are input rotation elements Since the first ring gear R1 and the third ring gear R3, which are output rotation elements, are always connected to S2, and the input rotation speed “1” to the first carrier C1 and the second sun gear S2 is maintained. On the other hand, the output rotation speeds from the first ring gear R1 and the third ring gear R3 are determined, and this becomes the output rotation speed Nr in the direction opposite to that at the time of forward movement.

  As described above, the rotational speeds N1 to N8 and Nr are set to N1 <N2 <N3 <N4 <N5 <N6 <N7 <N8 and Nr <0 by the combination of the engagement of the frictional engagement elements shown in FIG. In addition, N6 = 1 is obtained by the above-described configuration, so that an automatic transmission in which the sixth speed is a direct connection stage with a reduction gear ratio “1” can be obtained with eight forward speeds and one reverse speed.

  Therefore, the number of speed reduction stages is greater than that of an automatic transmission having a 5-speed direct connection stage, and the overall reduction ratio can be increased. When applied to a small displacement engine, the final reduction ratio Increase in the number of differential gears or drive units, the deterioration of the mounting capability in the engine room, etc., and the appropriate gear step between the gears can be set. It becomes possible to realize driving force and start acceleration.

  Here, if the number of teeth of each gear of the first to fourth gear sets PG1 to PG4 is set as shown in FIG. 12, for example, the reduction ratio of each gear stage and the gear steps between adjacent forward gear stages are shown in FIG. As shown.

  Compared with the automatic transmission in which the direct connection stage described in the above-mentioned Patent Document 2 is a 5-speed automatic transmission according to FIG. As a result, the gear step between the first and second gears is extremely larger than that between the other gears. On the other hand, in the automatic transmission 10 according to the embodiment of the present invention, each gear is The gear steps in between are within a narrow range of 1.1 to 1.5, and a very even distribution of gear steps is realized.

  As shown in FIG. 1, in this embodiment, the first gear set PG1 having the first carrier C1 to which the input shaft 12 is always connected, and the second gear set having the second sun gear S2 to which the input shaft 12 is always connected. PG2 is disposed closer to the drive source side in the axial direction than the other planetary gear sets PG3 and PG4. Therefore, the input shaft 12 can be shortened compared to the case where the first to fourth gear sets PG1 to PG4 are arranged in a different order. In addition, since the clutches CL1 to CL3 are not interposed between the first gear set PG1 and the second gear set PG2 in the axial direction, the input shaft 12 can be further shortened. As a result, the inertial mass on the input side is reduced, so that the inertia phase period during the shift operation can be shortened, and a quick shift operation can be realized.

  Note that the automatic transmission 10 according to the present embodiment is of a vertical type for front engines and rear drive vehicles in which the input and output shafts are arranged on the same axis, but the same regarding the gear set and the frictional engagement element. With this configuration, it is possible to configure a horizontal automatic transmission for a front engine / front drive vehicle or the like.

  As shown in FIG. 15, in the automatic transmission 10 ′ in which the automatic transmission 10 of the above embodiment is changed to the horizontal type, an output gear 20 is provided at the end of the output shaft 13 ′ on the non-driving side. . The output gear 20 is connected to an input gear (not shown) of a differential mechanism integrated with the automatic transmission 10 ′ via gears 22 and 23 on the counter shaft 21, and the output gear 13 ′. To the input gear constitutes the final reduction gear. Other configurations are the same as those of the vertical automatic transmission 10.

  That is, also in the automatic transmission 10 ′ shown in FIG. 15, the first and second gear sets PG1 and PG2 having rotating elements that are always drivingly connected to the input shaft 12 are arranged on the driving side with respect to the other gear sets PG3 and PG4. Therefore, the input shaft 12 can be shortened and thus reduced in weight, whereby the inertia phase period during the shift operation can be shortened, and a rapid shift operation can be realized.

  As described above, according to the present invention, an automatic transmission with eight forward speeds capable of setting the direct connection speed to the sixth speed and appropriately setting the gear steps between the respective speed speeds is realized. There is a possibility of being suitably used in the technical field of manufacturing automatic transmissions for vehicles or vehicles.

10, 10 'automatic transmission 11, 11' transmission case 12, 12 'input shaft 13, 13' output shaft 20 output gear PG1-PG4 first to fourth planetary gear sets S1-S4 sun gear R1-R4 ring gear C1-C4 Carriers CL1 to CL3 First to third clutches BR1 and BR2 First and second brakes

Claims (2)

In the transmission case,
An input shaft coupled to the drive source;
An output member disposed coaxially with the input shaft and coupled to a differential mechanism;
A single pinion type first planetary gear set having a first sun gear, a first carrier and a first ring gear;
A double pinion type second planetary gear set having a second sun gear, a second carrier, and a second ring gear;
A double pinion type third planetary gear set having a third sun gear, a third carrier, and a third ring gear;
A single pinion type fourth planetary gear set having a fourth sun gear, a fourth carrier, and a fourth ring gear;
First, second and third clutches;
First and second brakes;
An automatic transmission with
The input shaft, the first carrier, and the second sun gear are always connected,
The output member, the first ring gear and the third ring gear are always connected,
The third sun gear and the fourth ring gear are always connected,
The second ring gear and the fourth carrier are always connected,
The first clutch connects and disconnects the second carrier and the fourth sun gear;
The second clutch connects and disconnects the first sun gear and the fourth sun gear;
The third clutch connects and disconnects the fourth sun gear and the fourth ring gear;
The first brake connects and disconnects the second carrier and the transmission case,
The second brake connects and disconnects the third carrier and the transmission case;
When the first, second, and third clutches are engaged and the first and second brakes are released, a sixth speed with a reduction ratio of 1 is formed, and
The first and second planetary gear sets each having a first carrier and a second sun gear, to which the input shaft is always connected, are arranged closer to the drive source side in the axial direction than the other planetary gear sets. Automatic transmission. Of the first, second and third clutches and the first and second brakes,
First speed is formed when the third clutch, the first brake and the second brake are engaged,
Second speed is formed when the first clutch, the first brake and the second brake are engaged,
Third speed is formed when the first clutch, the third clutch and the second brake are engaged,
When the first clutch, the second clutch, and the second brake are engaged, the fourth speed is formed,
When the second clutch, the third clutch and the second brake are engaged, the fifth speed is formed,
Seventh speed is formed when the second clutch, the third clutch and the first brake are engaged,
8-speed is formed when the first clutch, the second clutch and the first brake are engaged,
The automatic transmission according to claim 1, wherein a reverse speed is formed when the second clutch, the first brake, and the second brake are engaged.

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