JPH08100844A - Power transmitting device for automatic transmission - Google Patents

Abstract

PURPOSE: To enable a length to effectively shorten in the axial direction of an automatic transmission by providing a hub part of a clutch drum overlapped in an axial line direction with a member of constituting a power transmitting device. CONSTITUTION: In the vicinity of a rear end part of an automatic transmission AT, an almost cylindrical boss part 61 is integrally provided with a transmission case 21. In this boss part 61, its outside arranged 3-4 clutch 40 and reverse clutch 42 are rotatably supported, on the other hand, to rotatably support a turbine shaft 3, arranged inside this boss part, through a connecting part 68b of a hub part 68 of the 3-4 clutch 40. A seal part 66a of a hub part 66 of a reverse clutch drum 65 and a seal 68a of the hub part 68 of a 3-4 clutch drum 67 are arranged to overlap in a longitudinal direction. The seal part 66a and the connecting part 68b are also overlapped in the longitudinal direction. Consequently, the reverse clutch 42 and the 3-4 clutch 40 are arranged adjacently in the longitudinal direction, to enable an axial direction length to shorten of the transmission.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device for an automatic transmission.

[0002]

2. Description of the Related Art Generally, an automatic transmission for an automobile is provided with a torque converter and a mechanical transmission mechanism, and the torque converter shifts the torque of a crankshaft, that is, the output torque of an engine, and outputs it to a turbine shaft.
The speed change mechanism further changes the torque of the turbine shaft and outputs it from the counter gear to the drive wheel side. Here, the speed change mechanism is usually provided with one or a plurality of planetary gear mechanisms including a plurality of rotating members such as a sun gear, a ring gear, a pinion gear, and a carrier. By changing the power transmission characteristics of the planetary gear mechanism at the time of speed change, It is designed to shift gears.

In the automatic transmission, a clutch for turning on (transmitting) and turning off (interrupting) torque transmission to a predetermined rotating member in order to switch the power transmission characteristic or power transmission path of the planetary gear mechanism, a predetermined transmission. Various hydraulic friction elements such as a brake for turning on (fixing) and turning off (release) the braking of the rotating member are provided. Further, the automatic transmission is provided with a hydraulic mechanism that supplies and discharges working hydraulic pressure to and from each of these friction elements, and this hydraulic mechanism switches the on / off pattern of each friction element, thereby performing gear shifting. It is like this.

In such an automatic transmission, the torque converter and the speed change mechanism are usually arranged in line in the axial direction of the turbine shaft. Further, in the speed change mechanism, the turbine shaft is arranged such that the shaft center of the speed change mechanism extends over substantially the entire length of the speed change mechanism, and each of the planetary gear mechanism, the friction element, the counter gear, the counter gear support portion, etc. Most of the members are arranged in line around the turbine shaft in the axial direction of the turbine shaft.
(For example, Japanese Unexamined Patent Publication No. 1-238736, Japanese Utility Model Publication No. 2-
(See 103553 publication).

[0005]

Therefore, the automatic transmission becomes relatively long in the axial direction thereof, that is, in the turbine shaft axial direction, and particularly long in the axial direction when the transmission mechanism is provided with a plurality of planetary gear mechanisms. Become. On the other hand, in recent years, FF type (front engine / front drive)
However, in such FF type vehicles, a power train including an engine and an automatic transmission is often mounted horizontally on the vehicle body. This is because if the powertrain is installed horizontally, the axis of the output shaft (counter gear) of the powertrain and the axis of the drive wheel axle will be parallel, and the power transmission mechanism from the powertrain to the axle will be simplified. .

However, when the power train is laterally mounted on the vehicle body as described above, the space in the width direction of the engine room is limited. Therefore, when the automatic transmission becomes axially long, the power in the engine room is reduced. There is a problem that the layout of the train or other various devices becomes difficult. Therefore, there is a demand for effective means capable of reducing the axial length of the automatic transmission as much as possible.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide means for effectively reducing the axial length of an automatic transmission. .

[0008]

In order to achieve the above object, a first aspect of the present invention is directed to a clutch drum by a boss portion extending from the mission case in the mission case axial direction in the vicinity of an axis of the mission case. In a power transmission device of an automatic transmission in which a hub is supported,
A seal ring is attached to the outer peripheral portion of the boss portion, and a seal portion that extends in the mission case axial direction and seals the seal ring is provided in the hub portion of the clutch drum with respect to the members constituting the power transmission device and the axial direction. Provided is a power transmission device for an automatic transmission, which is provided so as to overlap.

A second aspect of the present invention is the power transmission device for an automatic transmission according to the first aspect, wherein the first boss is provided by the boss portion.
The drum of the second clutch and the drum of the second clutch are supported, and the drum of the second clutch is arranged inside the drum of the first clutch, while the large diameter portion and the small diameter portion are formed on the boss portion. Is formed, the hub portion of the drum of the first clutch is supported by the large diameter portion, the hub portion of the drum of the second clutch is supported by the small diameter portion, and the hub portion of the drum of the first clutch and the A power transmission device for an automatic transmission, characterized in that the hub portion of the drum of the second clutch is arranged so as to overlap in the axial direction of the transmission case.

According to a third aspect of the present invention, in the power transmission device for an automatic transmission according to the second aspect, the vertical wall portion of the drum of the second clutch is in the axial direction of the hub portion of the drum of the first clutch and the transmission case axial direction. A power transmission device for an automatic transmission, characterized in that it is formed and arranged so as to bulge toward the vertical wall portion side of the drum of the first clutch so as to overlap.

A fourth aspect of the present invention provides a power transmission device for an automatic transmission characterized in that, in the power transmission device according to the third invention, the return spring of the first clutch is a diaphragm spring.

[0012]

EXAMPLES Examples of the present invention will be specifically described below.
First, a schematic structure of an automatic transmission according to the present invention and its operation / function will be described. As shown in Figure 2 and Figure 3, FF type (front engine / front drive)
The automatic transmission AT, which is one of the components of the power train horizontally installed in the automobile, is basically arranged to change the torque of the crankshaft 1 (engine output shaft) by the torque converter 2 to the turbine shaft 3. The torque of the turbine shaft 3 is output by the mechanical speed change mechanism 4 and output to the counter gear 5.

The counter gear 5 of the automatic transmission AT
After that, the torque of the first intermediate gear 7 and the second intermediate gear 8 attached to the intermediate shaft 6 and the final gear 9
Is transmitted to both drive wheels (not shown) via the front differential 10 and both front axle shafts 11 and 12. In the following, for convenience, the crankshaft side (right side in FIGS. 1 to 3) when viewed in the axial direction of the turbine shaft 3 (left and right directions in FIGS. 1 to 3) is referred to as “front”,
The opposite direction is called "back".

The torque converter 2 is arranged near the front end of the automatic transmission AT, and is substantially connected to the crankshaft 1 via a pump case 15 and a pump 16 (pump impeller) which rotates integrally with the crankshaft 1. , A turbine 17 (turbine runner) that is arranged opposite to the pump 16 and is rotationally driven by hydraulic oil discharged from the pump 16 and that is connected to the turbine shaft 3 and rotates integrally with the turbine shaft 3, and the pump 16 and the turbine 17. And a stator 18 for rectifying the working oil that flows back from the turbine 17 to the pump 16 in a direction that assists the rotation of the pump 16. Then, the torque converter 2 basically changes the torque of the crankshaft 1 to
The speed is changed at a speed ratio determined according to the rotational speed difference between the pump 16 and the turbine 17, and the speed is output to the turbine shaft 3. Here, the stator 18 is supported by a transmission case 21 (transmission case) via a one-way clutch 19 for the stator and a support member 20. Further, an oil pump 22 for supplying hydraulic oil to a hydraulic mechanism (not shown) of the automatic transmission AT is disposed slightly behind the torque converter 2, and the oil pump 22 is connected to the pump 16 via a connecting member 23. It is designed to be driven by rotation.

Further, the torque converter 2 is disposed between the vertical wall portion of the pump case 15 and the turbine 17 when viewed in the front-rear direction, and in a predetermined operating region where the torque increasing action of the torque converter 2 cannot be expected, the fuel efficiency is improved. A lock-up clutch 24 that directly connects the crankshaft 1 and the turbine shaft 3 is provided in order to increase the torque.

The speed change mechanism 4 is a planetary gear system having a first planetary gear mechanism 25 arranged on the front side behind the torque converter 2 and a second planetary gear mechanism 26 arranged on the rear side thereof, and the internal structure thereof. Range by switching the power transmission characteristics or power transmission path in
(P, R, N, D, L, etc.) and the shift speed (1st to 4th speed) can be switched.

Specifically, the first planetary gear mechanism 25 includes
A first sun gear 27 loosely fitted to the turbine shaft 3;
A first carrier 28 whose front end is connected to the counter gear 5 and rotates integrally with the counter gear 5, a first pinion gear 29 which is rotatably supported by the first carrier 28 and which meshes with the first sun gear 27, and a first pinion gear. 29
A first ring gear 30 that meshes with the first ring gear 30 is provided.

On the other hand, the second planetary gear mechanism 26 is loosely fitted to the turbine shaft 3 (more specifically, loosely fitted to the second carrier 33, which will be described later, loosely fitted to the turbine shaft 3). A sun gear 32, a second carrier 33 whose front portion is connected to the first ring gear 30 and rotates integrally with the first ring gear 30, and a second gear 33 which is rotatably supported by the second carrier 33 and meshes with the second sun gear 32. A two-pinion gear 34 and a second ring gear 35 which is connected to the first carrier 28 and rotates integrally with the first carrier 28 are provided.

The transmission mechanism 4 has various hydraulic friction elements for switching power transmission characteristics or power transmission paths inside the planetary gear mechanisms 25 and 26, and a predetermined rotating member that rotates in one direction. It is provided with a one-way clutch that is restricted to only. Specifically, near the front end of the transmission mechanism 4, the first connecting shaft 38 that is connected to the first sun gear 27 and rotates integrally with the first sun gear 27 and the turbine shaft 3 are connected and disconnected (on / off). A forward clutch 39 is provided. Further, in the vicinity of the rear end of the speed change mechanism 4, a 3-4 clutch 40 that connects (turns on / off) the first carrier 33 and the turbine shaft 3 and a second sun gear 32 are connected to rotate integrally with the sun gear 32. There is provided a second connecting shaft 41 that operates and a reverse clutch 42 that connects (turns on / off) the turbine shaft 3.

In the vicinity of the rear end portion of the speed change mechanism 4, a band brake type 2-4 brake 43 for further fixing and releasing (on / off) the second connecting shaft 41 is provided on the outer peripheral portion of the reverse clutch 42. It is provided so as to surround it. Further, the second carrier 33 is fixed / released (on / off) at a position slightly forward of the first planetary gear mechanism 25.
A low reverse brake 44 is provided.

Further, at a position slightly forward of the first planetary gear mechanism 25, the second carrier 33 and a case integrally formed with the mission case 21 so as to extend inward from the inner peripheral surface of the mission case 21. A one-way clutch 47 is provided between the extension portion 46 and the one-way clutch 47 for limiting the rotation direction of the second carrier 33 to only one direction. In addition, an assembly (hereinafter, referred to as a rotating body A) that is configured by the counter gear 5, the first carrier 28, and the second ring gear 35 and integrally rotates (hereinafter, referred to as a rotating body A) is
It is rotatably supported by the case extending portion 46.

Here, each of the friction elements 39, 40, 42,
Although not shown in detail, 43 and 44 are adapted to be turned on and off by hydraulic oil or hydraulic pressure supplied and discharged from a hydraulic mechanism controlled by a control unit. And each friction element 39, 40, 42, 43, 44
Both planetary gear mechanisms 25, 2 according to the on / off pattern of
A power transmission characteristic or a power transmission path inside 6 is set, and a desired range or shift speed is set. The range is set by the driver's operation of the shift lever, but the shift speed is automatically set by the control unit according to the vehicle speed, the throttle opening, and the like.

Each friction element 39, 40, 42, 43, 44
Table 1 shows the relationship between the operating state of the one-way clutch 47 and the range or shift speed.

[0024]

[Table 1]

The gear shifting characteristics of the gear shifting mechanism 4 in each range or gear are as follows. In the P range or N range, all friction elements 39, 40, 42, 43,
44 is turned off, the torque of the turbine shaft 3 is not input to the transmission mechanism 4, and therefore the drive wheels are not driven.

In the R range, the reverse clutch 42 and the low reverse brake 44 are turned on and the other friction elements are turned off. At this time, the torque of the turbine shaft 3 is transmitted to the second sun gear 32 via the reverse clutch 42 and the second connecting shaft 41. On the other hand, since the low reverse brake 44 is turned on, the first ring gear 3
0 and the second carrier 33 and integrally assembled
(Hereinafter, this is referred to as a rotating body B) is fixed. For this reason, the second sun gear 32, the second pinion gear 34, and the second ring gear 35 form a fixed gear train that meshes in this order, and the rotating body A has the number of teeth a of the second sun gear 32 and the teeth of the second ring gear 35. It is rotationally driven in the opposite direction to the turbine shaft 3 with a gear ratio [b / a] larger than 1 determined by the number b (b> a). Then, the torque of the rotating body A is output to the drive wheel side, and the drive wheel is driven in the backward direction with high torque. The gear ratio here means a torque ratio.
Further, the number of gear teeth is almost proportional to the gear diameter.

In the D range first speed, the forward clutch 3
9 is turned on and the other friction elements are turned off. At this time,
The torque of the turbine shaft 3 is the forward clutch 39.
Is transmitted to the first sun gear 27 via the first connecting shaft 38. In this case, the rotating body B is rotationally driven in the direction opposite to the turbine shaft rotating direction, that is, in the direction that locks the one-way clutch 47, but the rotation of the rotating body B is locked by the one-way clutch 47. Therefore, the rotor A has a gear ratio [(c + d) / c] greater than 1 determined by the number c of teeth of the first sun gear 27 and the number d of teeth (d> c) of the first ring gear 30. Is driven to rotate in the same direction as. Then, the torque of the rotating body A is output to the drive wheel side, and the drive wheel is driven in the forward direction with high torque. In this case, since the one-way clutch 47 is in a free state during coasting (during non-driving), the power train is not reversely driven by the driving wheels and therefore engine braking cannot be obtained. However, at the first speed in the L range, the low reverse brake 44 is further turned on, so that engine braking can be obtained during coasting.

In the D range second speed or the L range second speed, the forward clutch 39 and the 2-4 brake 43 are turned on, and the other friction elements are turned off. At this time, since the 2-4 brake 43 fixes the assembly (hereinafter, referred to as the rotating body C) that is configured by the second sun gear 32 and the second connecting shaft 41 and integrally rotates, the rotating body B is the turbine. It rotates in the same direction as the shaft 3. Therefore, in this case, as compared with the case of the first speed in the D range, the rotation speed of the rotating body A increases by the amount of rotation of the rotating body B, and the gear ratio decreases accordingly. Therefore, the drive wheels are driven in the forward direction with a torque that is slightly lower than that in the first speed in the D range (higher than that in the third speed).

In the 3rd speed of the D range or the 3rd speed of the L range, the forward clutch 39 and the 3-4 clutch 40 are turned on, and the other friction elements are turned off. At this time, both planetary gear mechanisms 25 and 26 are locked, and therefore the turbine shaft 3 and the counter gear 5 are directly connected to each other, and the gear ratio is 1. In this case, the drive wheels are driven in the forward direction with a torque lower than that in the second speed, which corresponds to the gear ratio 1.

In the D range 4th speed or the L range 4th speed, 3-
The 4-clutch 40 and the 2-4 brake 43 are turned on, and the other friction elements are turned off. At this time, the torque of the turbine shaft 3 is transmitted to the rotating body B (second carrier 33) via the 3-4 clutch 40. On the other hand, since the rotating body C (second sun gear 32) is fixed by the 2-4 brake 43, the rotating body A has the number of teeth a of the second sun gear 32 and the number of teeth b of the second ring gear 35 (b> a). With the gear ratio smaller than 1 [b / (a + b)] determined by and, the rotational drive is performed in the same direction as the turbine shaft 3, and the drive wheels have a gear ratio smaller than 1.
Driven in the forward direction with low torque corresponding to (overdrive state).

The specific structure of the automatic transmission AT or the disposition structure of each member will be described below. As is clear from FIG. 3, in the automatic transmission AT, the turbine shaft 3 extends in the front-rear direction (the turbine shaft axial direction) over substantially the entire length of the automatic transmission AT in the vicinity of the axial center of the automatic transmission AT. Are arranged as follows. The front portion of the turbine shaft 3 is rotatably supported by the support member 20 fixed to the mission case 21, and the rear portion of the turbine shaft 3 is integrally formed with the mission case 21 as will be described later. By
The 3-4 clutch 40 is rotatably supported via the hub portion 68 (coupling portion 68b).

Then, various devices constituting the automatic transmission AT, that is, the torque converter 2, the speed change mechanism 4, the oil pump 22 and the like, and supporting portions or supporting members 20 of these respective devices, the case extending portion 46, and the boss portion 61. And the like are arranged around the turbine shaft 3 so as to surround the turbine shaft 3, and these devices and supporting portions are arranged in a line in the front-rear direction while partially overlapping each other.

Further, each member constituting the transmission mechanism 4, that is, the counter gear 5, the first and second planetary gear mechanisms 25, 26,
The friction elements 39, 40, 42, 43, 44, the one-way clutch 47, etc. are also arranged around the turbine shaft 3 so as to surround them, and they are arranged in a line in the front-rear direction while partially overlapping each other. It is located in.

As described above, in the automatic transmission AT, various devices or various members are arranged in a line in the front-rear direction while partially overlapping each other, so that the axial length of the automatic transmission AT is long. That is, the total length tends to be long. However, in the automatic transmission AT according to the present invention, various measures are made as described below, and the total length thereof is shortened as much as possible.

The support member 20 is integrally formed with a tubular portion 20a fitted on the turbine shaft 3 and a partition wall portion 20b fastened to the mission case 21. Here, the inner race of the stator one-way clutch 19 is attached to the outer periphery of the front end of the tubular portion 20a by spline fitting. The outer race of the stator one-way clutch 19 is fixed to the stator 18. The partition wall portion 20b is fastened and fixed to the front end portion of the mission case 21 by using fastening bolts 52 together with the pump casing 51 of the oil pump 22.

Further, a converter case 50 is attached to the front end of the mission case 21 so as to abut the peripheral edge of the partition wall 20b and the peripheral edge of the pump casing 51. Here, the partition wall portion 20b has a diameter slightly larger than that of the pump casing 51, and the peripheral edge portion thereof is fitted into the recessed portion 50a formed in the converter case 50. In this way, the partition wall portion 20b has the concave portion 50a.
Since it has a shape to be fitted with, the work for attaching the support member 20 or the casing 51 to the mission case 21 is streamlined. That is, in such work, first, the mission case 21 is arranged so that the front end portion thereof faces downward, and then the partition wall portion 20b is brought into contact with the front end portion of the mission case 21 from below, and the converter case 50 is further mounted. The case 21 is brought into contact with the front end of the case 21 from the lower side, and then the partition wall 20b is attached to the pump casing
The bolt 52 is screwed into the mission case 21 after abutting 1 from the lower side, but when the bolt is screwed in, the partition wall portion 20b fits into the recess 50a, so that the support member 20
Is supported by the converter case 50, so that it is not necessary to support the support member 20 by hand.

The case extending portion 46 is slightly forward of the center position of the mission case 21 as viewed in the front-rear direction.
It is formed integrally with the mission case 21 so as to extend inward from the inner peripheral surface of the mission case 21. An edge formed in the case extending portion 46 so as to extend inward from the inner peripheral surface of the mission case 21 so that its expanded surface is substantially orthogonal to the turbine shaft axis L (see FIG. 1), that is, the mission case axis. Portion 46a and the edge portion 46a
And a cylindrical portion 46c which is formed in a substantially cylindrical shape and extends rearward from the inner end of the shaft, and the axis of which substantially coincides with the turbine shaft axis L (see FIG. 1).

The low reverse brake 44 is disposed near the peripheral portion of the substantially annular space formed between the outer peripheral surface of the cylindrical portion 46c and the inner peripheral surface of the mission case 21,
The front part of the rotating body B is arranged inside the low reverse brake 44, and the front part of the rotating body B and the cylindrical portion 46 are arranged.
A one-way clutch 47 is arranged between the two and c.
In this way, the low reverse brake 44 and the one-way clutch 47 are arranged so as to overlap each other in the front-rear direction, that is, to be layered in the radial direction, so that the total length of the automatic transmission AT is shortened.

A little forward of the case extending portion 46,
A substantially columnar counter gear 5 is arranged, and a forward clutch 39 is arranged slightly in front of the counter gear 5. That is, the counter gear 5 is arranged between the case extending portion 46 and the forward clutch 39 when viewed in the front-rear direction. Here, the rotating body A including the counter gear 5 is rotatably supported by the inner peripheral portion of the cylindrical portion 46c via the roller bearing 48.

As shown in FIG. 1, near the rear end of the automatic transmission AT, a substantially cylindrical boss portion 61 extending forward from the rear end wall 21a of the mission case 21 near the axis of the mission case 21. Are integrally provided with the mission case 21. A large diameter portion 62 having a relatively large diameter is formed at the rear portion of the boss portion 61, while a small diameter portion 63 having a relatively small diameter is formed at the front portion, and the large diameter portion 62 and the small diameter portion are formed. A substantially annular recess 60 is formed near the boundary with 63. A plurality of seal rings 64 are attached to the outer peripheral portion of the large diameter portion 62 and the outer peripheral portion of the small diameter portion 63, respectively. The boss portion 61 rotatably supports the 3-4 clutch 40 and the reverse clutch 42 arranged on the outer side thereof, and the turbine shaft 3 arranged on the inner side of the boss portion 61 of the hub portion 68 of the 3-4 clutch 40. It is rotatably supported via the connecting portion 68b.

A 3-4 clutch 40, a reverse clutch 42 and a 2-4 brake 43 are arranged in the mission case 21 near the rear end of the automatic transmission AT. Here, as a whole, the 3-4 clutch 40 is arranged in the space formed inside the reverse clutch 42,
The 2-4 brake 43 is arranged so as to surround the outer peripheral portion of the reverse clutch 42, and thus the 3-4 clutch 4 is provided.
0, reverse clutch 42 and 2-4 brake 43,
They overlap in the front-rear direction, that is, are arranged in layers in the radial direction of the mission case 21. As a result, the axial length of the automatic transmission AT is shortened. The reverse clutch 42 and the 3-4 clutch 40 are
Each corresponds to the “first clutch” and the “second clutch” described in the claims.

The reverse clutch 42 is provided with a substantially cylindrical reverse clutch drum 65 having a tubular portion 65a and a vertical wall portion 65b, and a hub portion 66 is provided at an inner end portion of the vertical wall portion 65b. There is. The hub portion 66 of the reverse clutch drum 65 is rotatably supported by the large diameter portion 62 of the boss portion 61. Here, the hub portion 66 is integrally formed with a substantially cylindrical seal portion 66a that extends forward (in the axial direction of the transmission case) and seals the seal ring 64.

On the other hand, the 3-4 clutch 40 has a cylindrical portion 67.
A substantially cylindrical 3-4 clutch drum 67 including a and a vertical wall portion 67b is provided, and a hub portion 68 is provided at an inner end portion of the vertical wall portion 67b. The hub portion 68 of the 3-4 clutch drum 67 is rotatably supported by the small diameter portion 63 of the boss portion 61. Here, the hub 68 has a seal portion 68 that extends forward and seals the seal ring 64.
a is integrally formed. Further, the seal portion 68a is formed and arranged so as to surround the front portion of the boss portion 61 so as to extend from the outside to the inside of the boss portion 61 at the front end portion thereof.
A connecting portion 68b that connects the 3-4 clutch drum 67 to the turbine shaft 3 is integrally formed. Therefore,
The 3-4 clutch drum 67 rotates integrally with the turbine shaft 3.

Here, the 3-4 clutch drum 67 is arranged inside the river clutch drum 65. The vertical wall portion 67b of the 3-4 clutch drum 67 is connected to the seal portion 66a of the hub portion 66 of the reverse clutch drum 65.
So as to overlap in the front-rear direction (the axial direction of the transmission case), that is, in the rearward direction, that is, on the side of the vertical wall portion 65b of the reverse clutch drum 65. Further, the seal portion 66a (front portion) of the hub portion 66 of the reverse clutch drum 65 and the seal portion 68a (rear portion) of the hub portion 68 of the 3-4 clutch drum 67 are formed and arranged so as to overlap in the front-rear direction. Has been done. Specifically, the seal portion 68
When the rear part of a enters the recess 60, the seal part 66a and the seal part 68a overlap each other. Further, the seal portion 66a and the connecting portion 68b also overlap each other in the front-rear direction. Since the reverse clutch drum 65 and the 3-4 clutch drum 67 are formed and arranged in this way, the reverse clutch 42 and 3-4 are arranged.
The clutch 40 is arranged close to the front-rear direction, and the axial length of the automatic transmission AT is significantly reduced.

The reverse clutch 42 has a plurality of outer plates 71 that are spline-fitted to the inner peripheral portion of the cylindrical portion 65a of the reverse clutch drum 65, and spline-fitted to the outer peripheral portion of the cylindrical portion 67a of the 3-4 clutch drum 67. Inner plates 72 are provided, and the outer plates 71 and the inner plates 72 are arranged alternately in the front-rear direction.

Further, on the rear side of the assembly composed of both plates 71, 72 (hereinafter, referred to as the first plate group 71, 72), the substantially annular space formed in the reverse clutch drum 65 has a first The 1st piston 73 is inserted, and this 1st piston 73 is the 1st return spring 7
4 always biases backward.
A diaphragm spring having a compact shape is used as the first return spring 74, which also shortens the axial length of the automatic transmission AT.

Here, the operating oil (hydraulic pressure) is supplied to the first oil chamber 75 defined on the rear side of the first piston 73 via the first oil passage 90.
Is supplied to the first piston 7 by the hydraulic pressure.
3 is pushed forward and its front end is the first plate group 7
1, 72 are pressed forward, and as a result, the outer plate 71 and the inner plate 72 adjacent to each other are frictionally engaged, and the reverse clutch 42 is turned on (fastened). On the other hand, the first oil chamber 7
When the hydraulic oil (hydraulic pressure) in 5 is released via the first oil passage 90, the first return spring 74 moves the first piston 73 rearward, and the first return spring 74 moves between the outer plate 71 and the inner plate 72. The frictional engagement is released and the reverse clutch 42 is turned off (released).

On the other hand, the 3-4 clutch 40 includes a plurality of outer plates 77 which are spline-fitted to the inner peripheral portion of the cylindrical portion 67a of the 3-4 clutch drum 67, and the second carrier 33.
The inner plate 7 that is spline-fitted to the outer peripheral portion of the substantially cylindrical connecting member 78 attached to the rear end of the (rotating body B).
9 are provided, and the outer plates 77 and the inner plates 79 are alternately arranged in the front-rear direction.

Then, on the rear side of the assembly composed of both plates 77, 79 (hereinafter, referred to as the second plate group 77, 79), a substantially annular space formed in the 3-4 clutch drum 67 is formed. Is fitted with the second piston 80,
The second piston 80 is always biased rearward by a second return spring 81. Second
As the return spring 81, a diaphragm spring having a compact shape is used.

Here, the hydraulic oil (hydraulic pressure) is supplied to the second oil chamber 82 defined on the rear side of the second piston 80 via the second oil passage 91.
Is supplied to the second piston 8 by the hydraulic pressure.
0 is pushed forward, and its front end is the second plate group 7
7, 79 are pressed forward, and as a result, the outer plate 77 and the inner plate 79 which are adjacent to each other are frictionally engaged with each other, and 3-4
The clutch 40 is turned on (engaged). On the other hand, the second oil chamber 82
When the operating oil (hydraulic pressure) inside is released through the second oil passage 91, the second return spring 81
The piston 80 is moved rearward, the frictional engagement between the outer plate 77 and the inner plate 79 is released, and the 3-4 clutch 40 is turned off (released).

As described above, since the total length of the automatic transmission AT according to this embodiment is shortened by various measures, the total length of the power train is shortened accordingly.
It becomes easy to mount the power train horizontally on an automobile.

[0052]

According to the first aspect of the invention, the seal portion, which extends in the axial direction of the transmission case and seals the seal ring, overlaps the hub portion of the drum of the clutch with the member constituting the power transmission device in the axial direction. Since the hub portion is supported by the boss portion, the sealing performance between the boss portion and the hub portion is improved without increasing the overall length.

According to the second invention, basically, the same operation and effect as those of the first invention can be obtained. Furthermore, the first and second
Of the first clutch drum hub and the second clutch
Since the hub portion of the clutch drum and the hub portion of the drum overlap so as to overlap in the axial direction of the transmission case, both clutches are placed close to each other, and the axial length of the automatic transmission, that is, the overall length is shortened accordingly. It Therefore,
The overall length of the power train is shortened, and it becomes easy to mount the power train horizontally on an automobile.

According to the third invention, basically the same action and effect as the second invention can be obtained. Further, since the vertical wall portion of the drum of the second clutch bulges so as to overlap the hub portion of the drum of the first clutch, both clutches are arranged close to each other, and the shaft of the automatic transmission is The length in the direction is further shortened.

According to the fourth invention, basically, the same operation and effect as those of the third invention can be obtained. Furthermore, since the return spring is a compact diaphragm spring, the axial length of the automatic transmission is further shortened.

[Brief description of drawings]

FIG. 1 is a side cross-sectional explanatory view of an essential part of an automatic transmission equipped with a power transmission device according to the present invention.

FIG. 2 is a skeleton diagram showing a schematic configuration of an automatic transmission including a power transmission device according to the present invention.

FIG. 3 is a side sectional view showing an automatic transmission equipped with the power transmission device according to the present invention.

[Explanation of symbols]

 AT ... Automatic transmission 21 ... Mission case 40 ... 3-4 clutch 42 ... Reverse clutch 61 ... Boss portion 62 ... Large diameter portion 63 ... Small diameter portion 64 ... Seal ring 65 ... Reverse clutch drum 65b ... Vertical wall portion 66 ... Hub portion 66a ... Seal part 67 ... 3-4 clutch drum 67b ... Vertical wall part 68 ... Hub part 68a ... Seal part 74 ... 1st return spring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Iwa ▲ Saki ▼ Tatsuhiko Shinichi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd.

Claims (4)

[Claims] 1. A power transmission device for an automatic transmission in which a hub portion of a drum of a clutch is supported by a boss portion extending from the mission case in the mission case axial direction in the vicinity of an axis of the mission case. A seal ring is attached to the outer periphery of the boss portion, and a seal portion that extends in the mission case axial direction and seals the seal ring is provided in the hub portion of the clutch drum over the member forming the power transmission device in the axial direction. A power transmission device for an automatic transmission, which is provided by being wrapped. 2. The power transmission device for an automatic transmission according to claim 1, wherein the drum of the first clutch and the drum of the second clutch are supported by the boss portion. While the drum of the second clutch is arranged inside the drum, a large diameter portion and a small diameter portion are formed in the boss portion, and the hub portion of the drum of the first clutch is supported by the large diameter portion. The hub portion of the drum of the clutch is supported by the small diameter portion, and the hub portion of the drum of the first clutch and the hub portion of the drum of the second clutch are arranged so as to overlap in the axial direction of the mission case. A power transmission device for an automatic transmission, characterized in that 3. The power transmission device for an automatic transmission according to claim 2, wherein the vertical wall portion of the drum of the second clutch overlaps the hub portion of the drum of the first clutch in the axial direction of the transmission case. As described above, the power transmission device for an automatic transmission characterized in that it is formed and arranged so as to bulge toward the vertical wall portion side of the drum of the first clutch. 4. The power transmission device for an automatic transmission according to claim 3, wherein the return spring of the first clutch is a diaphragm spring.