JP6107576B2 - Automatic transmission - Google Patents

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. 15).

  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, as the number of gear stages increases, the number of parts increases and the assembly becomes complicated. Therefore, when creating a new automatic transmission, it is necessary to consider the layout of the component parts in consideration of the assemblability. .

  In view of the above situation regarding the multi-stage automatic transmission, the present invention can set the direct connection speed to 6-speed, can appropriately distribute the gear steps between the respective speed speeds, and is excellent in assemblability. The realization of an automatic transmission with 8 forward speeds has been achieved, and as a result of intensive studies, this has been achieved.

  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 double 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 single 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;
With
The transmission case is an eight- speed automatic transmission with an opening on the opposite side of the drive source in the axial direction,
The input shaft, the second sun gear, and the fourth carrier are always connected,
The output member, the first ring gear and the fourth ring gear are always connected,
The first sun gear and the third ring gear are always connected,
The second ring gear and the third carrier are always connected,
The first clutch connects and disconnects the second carrier and the third sun gear;
The second clutch connects and disconnects the third sun gear and the third ring gear;
The third clutch connects and disconnects the third sun gear and the fourth sun gear;
The first brake connects and disconnects the second carrier and the transmission case,
The second brake connects and disconnects the first carrier and the transmission case;
Of the first, second, and third clutches and the first and second brakes, any three frictional engagement elements are engaged, and the remaining two frictional engagement elements are brought into a non-engagement state. Configured to form steps,
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 brakes are arranged at an end portion on the opening side in the transmission case.

The invention according to claim 2 is the invention according to claim 1,
The transmission case includes an end cover that closes the opening;
The first and second brakes are provided between the second carrier or the first carrier and the end cover.

Further, the invention according to claim 3 is the invention according to claim 1 or 2,
Of the first, second and third clutches and the first and second brakes,
First speed is formed when the second 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 second clutch and the second brake are engaged,
When the first clutch, the third 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 third clutch and the first brake are engaged,
A reverse speed is formed when the third 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, in the transmission case, the first and second brakes connected to the transmission case are disposed at the end of the opening side (counter drive source side). Can be easily assembled from the opening of the transmission case without interfering with the clutch or the planetary gear set. For this reason, it is possible to achieve better assemblability compared to the case where at least one of the first and second brakes is disposed at the axial intermediate position or the drive source side.

  Further, according to the invention described in claim 2, since the first and second brakes are provided between the predetermined rotation element of the planetary gear set and the end cover, the frictional engagement elements and pistons constituting these brakes are provided. The predetermined parts such as can be easily assembled to the main body side of the transmission case together with the end cover in a state of being sub-assembled to the end cover. Therefore, the assembly property can be further improved.

  Further, according to the invention described in claim 3, 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 first to fifth speeds, the seventh speed, the eighth speed, and the reverse speed. The ratio is realized.

1 is a schematic diagram of an automatic transmission according to a first 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 skeleton diagram of an automatic transmission concerning a 2nd embodiment. 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. 14 with the comparative example. It is a skeleton figure concerning the modification of a 1st embodiment.

  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 a first embodiment of the present invention. This automatic transmission 10 includes an input shaft 12 and an input shaft 12 in a transmission case 11. And an output gear 13 disposed on the same axis. The output gear 13 is disposed within the transmission case 11 at the end on the input side (drive source side) on the right side of the drawing in the axial direction. Although not shown, the output gear 13 is connected to an input gear of a differential mechanism integrated with the automatic transmission 10 via a gear on a counter shaft, and a gear from the output gear 13 to the input gear. A final reduction gear is configured in a row.

  The transmission case 11 includes an opening 11a provided on the side opposite to the drive source in the axial direction, and an end cover 11b that closes the opening 11a.

  In the transmission case 11, the double pinion type first and second planetary gear sets (hereinafter simply referred to as “first and second”) are arranged in order from the opening 11 a side (counter drive source side) on the axis of the input shaft 12. PG1 and PG2 (referred to as “gear sets”) and single and pinion type third and fourth planetary gear sets (hereinafter simply referred to as “third and fourth gear sets”) PG3 and PG4 are disposed.

  The first to fourth gear sets PG1 to PG4 each have three rotation elements. As these rotation 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 gear set PG4 has a fourth sun gear S4, a fourth ring gear R4, and a fourth carrier C4.

  Here, the first and second gear sets PG1 and PG2 of the double pinion type include a first pinion meshed with the first and second sun gears S1 and S2, respectively, the first pinion and the first and second ring gears R1, The second pinions meshed with R2 are supported by the first and second carriers C1 and C2, respectively. The single pinion type third and fourth gear sets PG3 and PG4 have pinions meshed with the third and fourth sun gears S3 and S4 and the third and fourth ring gears R3 and R4, respectively. Are supported by the third and fourth carriers C3 and C4, respectively.

  In the automatic transmission 10, the first sun gear S1 and the third ring gear R3, the first ring gear R1 and the fourth ring gear R4, the second sun gear S2 and the fourth carrier C4, and the second ring gear R2 are used. And the third carrier C3 are always connected to each other. The input shaft 12 is always connected to the second sun gear S2 and the fourth carrier C4, and the output gear 13 is always connected to the first ring gear R1 and the fourth ring gear R4.

  A first clutch CL1 is disposed between the second gear set PG2 and the third gear set PG3. Between the third gear set PG3 and the fourth gear set PG4, the opening 21a side (counter drive source side) A second clutch CL2 and a third clutch CL3 are provided. The first clutch CL1 is disposed between the second carrier C2 and the third sun gear S3 so as to connect and disconnect them. The second clutch CL2 is connected to the third sun gear S3 and the third ring gear. The third clutch CL3 is disposed between the third sun gear S3 and the fourth sun gear S4 so as to connect / disconnect them. It has become.

  Further, the first and second brakes BR1 and BR2 are disposed on the opening 21a side (counter drive source side) of the first gear set PG1 from the opening 21a side. 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 first carrier. They are arranged between C1 and are connected to each other.

  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 gear set PG1 to PG4 is determined by the respective gear ratio, and in the double pinion type gear sets PG1 and PG2, the carrier, ring gear, sun gear In the single pinion type gear sets PG3 and PG4, the ring gear, the carrier, 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 second sun gear S2 and the fourth carrier C4 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 speeds of the rotation output from the first and fourth ring gears R1, R4 to the output gear 13, and the reciprocal of the output rotational speed is the deceleration at the corresponding speed stage. It becomes a ratio.

  First, at the first speed, as shown in FIG. 3, since the second clutch CL2 and the first and second brakes BR1 and BR2 are engaged, the rotational speeds of the first carrier C1 and the second carrier C2 are “0”. And the third sun gear S3 and the third ring gear R3 are coupled and the third gear set PG3 is integrated, so that the rotating elements of the third gear set PG3 rotate the same and are always connected to the third carrier C3. The first sun gear S1, which is always connected to the second ring gear R2 and the third ring gear R3, 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 first sun gear S1 of the gear set PG1, the rotational speed of the first ring gear R1 is determined, and this becomes the output rotational speed N1.

  Next, at the second speed, as shown in FIG. 4, the first clutch CL1 and the first and second brakes BR1 and BR2 are engaged, so that the rotation speeds of the first carrier C1 and the second carrier C2 are “ 0 "and the second carrier C2 and the third sun gear S3 are connected to each other so that the rotation of the third sun gear S3 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 third carrier C3 always connected thereto is determined. Thus, the rotational speed of the third ring gear R3 and the rotational speed of the first sun gear S1 always connected to the third ring gear R3 are determined. As a result, in the first gear set PG1, since the rotational speed of the first carrier C1 is “0”, the rotational speed of the first ring gear R1 is determined and becomes the output rotational speed N2.

  Next, at the third speed, as shown in FIG. 5, since the first and second clutches CL1 and CL2 and the second brake BR2 are engaged, first, the third sun gear S3 and the third ring gear R3 are coupled. Since the third gear set PG3 is integrated, the rotating elements of the third gear set PG3 rotate the same, and the second ring gear R2 always connected to the third carrier C3 and the second ring gear R3 always connected to the third ring gear R3. One sun gear S1 also rotates in the same manner.

  Further, the third sun gear S3 and the second carrier C2 are connected, so that the second gear set PG2 is also integrated, and as a result, the entire second and third gear sets PG2, PG3 are input to the second sun gear S2. It rotates together with the input rotation speed “1”.

  The rotational speed “1” is transmitted to the first sun gear S1 of the first gear set PG1 in which the rotational speed of the first carrier C1 is “0”, thereby determining the rotational speed of the first ring gear R1. This is the output rotation speed N3.

  Next, at the fourth speed, as shown in FIG. 6, since the first and third clutches CL1 and CL3 and the second brake BR2 are engaged, the rotational speed of the first carrier C1 becomes “0”. The second carrier C2, the third sun gear S3, and the fourth sun gear S4 are connected and rotate in the same direction.

  These conditions, the first sun gear S1 and the third ring gear R3 are always connected, the second ring gear R2 and the third carrier C3 are always connected, and the second sun gear S2 as the input rotation element and the fourth carrier are connected. From the condition that the first ring gear R1 and the fourth ring gear R4, which are output rotation elements, are always connected to each other and C4 is always connected, the input rotation speed “1” to the second sun gear S2 and the fourth carrier C4 is “1”. The rotational speeds of the first ring gear R1 and the fourth ring gear R4 with respect to "are determined, and this becomes the output rotational 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 third sun gear S3 and the third ring gear R3 are coupled. When the third gear set PG3 is integrated, the rotating elements of the third gear set PG3 rotate the same and are connected to the first sun gear S1 and the third sun gear S3 that are always connected to the third ring gear R3. The fourth sun gear S4 rotates in the same manner as these.

  As a result, in the first gear set PG1 and the fourth gear set PG4, the first sun gear S1 and the fourth sun gear S4 rotate the same, and the always connected first ring gear R1 and fourth ring gear R4 rotate the same, Further, from the condition that the rotation speed of the first carrier C1 is “0”, the rotation speeds of the first ring gear R1 and the fourth ring gear R4 that are output rotation elements are determined, and this rotation speed is determined as the output rotation speed N5. Become.

  Next, at the sixth speed, as shown in FIG. 8, since the first, second, and third clutches CL1, CL2, and CL3 are engaged, first, the third sun gear S3 and the third ring gear R3 are coupled. When the third gear set PG3 is integrated, the rotating elements of the third gear set PG3 rotate the same, and the second ring gear R2 always connected to the third carrier C3 and the first sun gear always connected to the third ring gear R3. S1 also rotates in the same manner, and the fourth sun gear S4 connected to the third sun gear S3 also rotates in the same direction.

  Further, since the third sun gear S3 and the second carrier C2 are connected, the second gear set PG2 is also integrated, and the rotating elements of the second gear set rotate the same, and the second sun gear S2 is always connected to the second sun gear S2. The fourth carrier C4 also rotates in the same manner. As a result, the fourth gear set PG4 is also integrated, and the fourth ring gear R4 and the first ring gear R1 always connected to the same also rotate in the same manner as the rotation elements. As a result, the first gear set PG1 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 second sun gear S2 and the fourth carrier C4 is output as it is from the first and fourth ring gears R1 and R4 as the output rotational speed N6. 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 third sun gear S3 and the third ring gear R3 are coupled. Since the third gear set PG3 is integrated, the rotating elements of the third gear set PG3 rotate the same, and the second ring gear R2 always connected to the third carrier C3 and the second ring gear R3 always connected to the third ring gear R3. The first sun gear S1 also rotates in the same manner, and the fourth sun gear S4 connected to the third sun gear S3 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 second sun gear S2 and the fourth carrier C4 are “1”, the rotation of each of the rotating elements rotating the same is performed. As the speed is determined, the rotational speed of the fourth ring gear R4 is determined accordingly, and this rotational speed becomes the output rotational speed N7.

  Next, at the eighth speed, as shown in FIG. 10, the first and third clutches CL1 and CL3 and the first brake BR1 are engaged, so that the rotational speed of the second carrier C2 is set to “0”. The rotational speeds of the third sun gear S3 and the fourth sun gear S4 connected thereto are also “0”.

  In the fourth gear set PG4, the rotation speed of the fourth carrier C4 is “1” and the rotation speed of the fourth sun gear S4 is “0”, so that the rotation of the fourth ring gear R4 is determined. The output rotation speed N8 is obtained.

  Further, at the reverse speed, as shown in FIG. 11, since the third clutch CL3 and the first and second brakes BR1 and BR2 are engaged, the third sun gear S3 and the fourth sun gear S4 are connected, As these rotate the same, the rotation speeds of the first and second carriers C1 and C2 become “0”.

  These conditions, the first sun gear S1 and the third ring gear R3 are always connected, the second ring gear R2 and the third carrier C3 are always connected, and the second sun gear S2 as the input rotation element and the fourth carrier are connected. Since the first ring gear R1 and the fourth ring gear R4, which are output rotating elements, are always connected to each other and C4 is always connected, the input rotational speed “1” to the second sun gear S2 and the fourth carrier C4 is increased. On the other hand, the output rotation speed from the first ring gear R1 and the fourth ring gear R4 is 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.

  As shown in FIG. 1, in the first embodiment, the first and second brakes BR <b> 1 and BR <b> 2 are disposed in the end portion on the opening 11 a side in the transmission case 11. Therefore, these brakes BR1 and BR2 can be easily assembled from the opening 11a of the transmission case 11 without interfering with the clutches CL1 to CL3 and the planetary gear sets PG1 to PG4. Therefore, better assemblability can be realized as compared with the case where at least one of the first and second brakes BR1 and BR2 is disposed at the axial intermediate position or the drive source side.

  Further, the first brake BR1 is provided between the second carrier C2 and the end cover 11b, and the second brake BR2 is provided between the first carrier C1 and the end cover 11b. Therefore, predetermined components such as frictional engagement elements and pistons constituting the brakes BR1 and BR2 are easily assembled to the main body side of the transmission case 11 together with the end cover 11b in a state where the end cover 11b is sub-assembled. Can do. Therefore, the assembly property of the automatic transmission 10 can be further improved.

  Next, an automatic transmission according to the second embodiment shown in FIG. 12 will be described.

  Also in the automatic transmission 20 according to the second embodiment, the transmission case 21 includes an opening 21a provided on the side opposite to the driving source in the axial direction and an end cover 21b that closes the opening 21a. In the case 21, an input shaft 22 and an output gear 23 are arranged on the same axis. Further, on the axis of the input shaft 22, the first and second gear sets PG1 and PG2 of the double pinion type, the third and fourth gear sets PG3 and PG4 of the single pinion type, and the first, second and third clutch CL1. , CL2 and CL3 and first and second brakes BR1 and BR2 are disposed.

  In addition, since the component on the said axis line is the same as 1st Embodiment, the code | symbol same as 1st Embodiment is used about the 1st-4th gear set, its rotation element, and each friction fastening element.

  The second embodiment differs from the first embodiment in the order of arrangement of the first to fourth gear sets on the axis, and accordingly, the arrangement of the frictional engagement elements is also different.

  That is, in the automatic transmission 20 according to the second embodiment, the first gear set PG1, the third gear set PG3, the second gear set PG2, and the second gear set PG2 are arranged on the axis of the input shaft 22 from the opening 21a side (counter drive source side). A fourth gear set PG4 is arranged.

  The second clutch CL2 is provided between the third gear set PG3 and the second gear set PG2, and the first clutch CL1 and the third clutch CL3 are provided between the second gear set PG2 and the fourth gear set PG4 from the opening 21a side. The first brake BR1 and the second brake BR2 are disposed from the opening 21a side on the opening 21a side of the first gear set PG1.

  As described above, in the automatic transmission 20 according to the second embodiment, the order of arrangement of the first to fourth gear sets PG1 to PG4 on the axis of the input shaft and each friction are compared with those in the first embodiment. The arrangement positions of the fastening elements CL1 to CL3, BR1, and BR2 are different from each other, but the other configurations are the same as those in the first embodiment.

  That is, also in the automatic transmission 20 according to the second embodiment, the first and second brakes BR1 and BR2 are disposed in the end portion on the opening 21a side (counter drive source side) in the transmission case 21. . Therefore, these brakes BR1 and BR2 can be easily assembled from the opening 21a of the transmission case 21 without interfering with the clutches CL1 to CL3 and the planetary gear sets PG1 to PG4. The first brake BR1 is provided between the second carrier C2 and the end cover 21b, and the second brake BR2 is provided between the first carrier C1 and the end cover 21b. Therefore, predetermined components such as the frictional engagement elements and pistons constituting the brakes BR1 and BR2 are easily assembled to the main body side of the transmission case 21 together with the end cover 21b in a state where the end cover 21b is sub-assembled. Can do. Therefore, as in the first embodiment, good assemblability can be realized.

  In the second embodiment, the rotational elements in each of the gear sets PG1 to PG4, that is, the connection relationship between the sun gear, the ring gear, and the carrier, the connection with the transmission case by the brake, or the connection with each other by the clutch. The relationship between the rotating elements is the same as in the first embodiment.

  That is, also in the automatic transmission 20 according to the second embodiment, the first sun gear S1 and the third ring gear R3, the first ring gear R1 and the fourth ring gear R4, the second sun gear S2 and the fourth carrier C4, and the second ring gear. R2 and the third carrier C3 are always connected, and the input shaft 22, the second sun gear S2, and the fourth carrier C4 are always connected, and the output gear 23, the first ring gear R1, and the fourth ring gear R4 are connected. Always connected.

  The first clutch CL1 is disposed between the second carrier C2 and the third sun gear S3 so as to connect and disconnect them. The second clutch CL2 is connected to the third sun gear S3 and the third ring gear. The third clutch CL3 is disposed between the third sun gear S3 and the fourth sun gear S4 so as to connect / disconnect them. It has become.

  Further, the first brake BR1 is disposed between the transmission case 21 and the second carrier C2, and connects and disconnects them. The second brake BR2 is connected to the transmission case 21 and the first carrier. They are arranged between C1 and are connected to each other.

  Therefore, also in the automatic transmission 20 according to the second embodiment, the three frictional engagement elements are selectively fastened according to the fastening table shown in FIG. 2, so that the automatic transmission 20 according to the first embodiment is similar to the automatic transmission 10 according to the first embodiment. , 8 forward speeds and reverse speeds are formed, and the 6th speed is the direct connection stage.

  Here, regarding the first and second embodiments, if the number of teeth of each gear of the first to fourth gear sets PG1 to PG4 is set as shown in FIG. 13, for example, the reduction ratio of each gear stage and the forward adjacent shift The gear steps between the stages are as shown in FIG.

  When this gear step distribution is compared with that of 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 speeds is extremely larger than that between the other gears. On the other hand, in the automatic transmissions 10 and 20 according to the embodiment of the present invention, The gear steps between the gears are within a narrow range of 1.1 to 1.5, and a very even gear step distribution is realized.

  The automatic transmissions 10 and 20 according to the first and second embodiments described above are of a horizontal type for a front engine / front drive vehicle in which an output gear is arranged coaxially with the input shaft. It is also possible to construct a vertical automatic transmission for a front engine, a rear drive vehicle or the like with the same configuration regarding the gear set and the frictional engagement element.

  This will be described by taking the automatic transmission 10 of the first embodiment as an example. As shown in FIG. 16, the automatic transmission 10 ′ changed to the vertical type is different from the horizontal type automatic transmission 10, The input side (drive source side) is the side opposite to the output side (left side in the figure), and the input shaft 12 ′ connected to the drive source extends from the left side to the right side in the figure and the second sun gear S 2 and the second It is connected to 4 carriers C4.

  Further, instead of the output gear 13 in the horizontal automatic transmission 10, an output shaft 13 'is disposed on the same axis as the input shaft 12' on the opposite input side. It is connected to the fourth ring gears R1 and R4. Furthermore, the opening 11a ′ and the end cover 11b ′ of the transmission case 11 ′ are arranged on the output side, and the second end from the opening 11a ′ side to the opening 11a ′ side (counter drive side) of the transmission case 11 ′. A brake BR2 and a first brake BR1 are provided. Other configurations are the same as those of the horizontal automatic transmission 10.

  Also in the automatic transmission 10 ′ shown in FIG. 16, the first brake BR1 is provided between the second carrier C2 and the end cover 11b ′, and the second brake BR2 is connected to the first carrier C1 and the end cover 11b. 'Is provided between. Therefore, in a state where predetermined parts such as frictional engagement elements and pistons constituting the brakes BR1 and BR2 are sub-assembled to the end cover 11b ′, the transmission cover 11b ′ and the main body side of the transmission case 11 ′ can be easily combined. Can be assembled.

  The above points are the same for the horizontal transmission type automatic transmission 20 according to the second embodiment, and this automatic transmission 20 can be similarly converted to a vertical type automatic transmission. .

  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, 20, 10 'automatic transmission 11, 21, 11' transmission case 11a, 21a, 11a 'opening of transmission case 11b, 21b, 11b' end cover 12, 22, 12 'input shaft 13, 23 output gear 13 'Output shaft PG1 to PG4 First to fourth planetary gear sets S1 to S4 Sun gear R1 to R4 Ring gear C1 to C4 Carrier CL1 to CL3 First to third clutches BR1, BR2 First and second brakes

Claims (3)

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 double 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 single 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;
With
The transmission case is an eight- speed automatic transmission with an opening on the opposite side of the drive source in the axial direction,
The input shaft, the second sun gear, and the fourth carrier are always connected,
The output member, the first ring gear and the fourth ring gear are always connected,
The first sun gear and the third ring gear are always connected,
The second ring gear and the third carrier are always connected,
The first clutch connects and disconnects the second carrier and the third sun gear;
The second clutch connects and disconnects the third sun gear and the third ring gear;
The third clutch connects and disconnects the third sun gear and the fourth sun gear;
The first brake connects and disconnects the second carrier and the transmission case,
The second brake connects and disconnects the first carrier and the transmission case;
Of the first, second, and third clutches and the first and second brakes, any three frictional engagement elements are engaged, and the remaining two frictional engagement elements are brought into a non-engagement state. Configured to form steps,
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 automatic transmission according to claim 1, wherein the first and second brakes are disposed at an end portion on the opening side in the transmission case. The transmission case includes an end cover that closes the opening;
The automatic transmission according to claim 1, wherein the first and second brakes are provided between the second carrier or the first carrier and the end cover. Of the first, second and third clutches and the first and second brakes,
First speed is formed when the second 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 second clutch and the second brake are engaged,
When the first clutch, the third 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 third clutch and the first brake are engaged,
The automatic transmission according to claim 1 or 2, wherein a reverse speed is formed when the third clutch, the first brake, and the second brake are engaged.

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