JPH06129501A - Power transmitting device of automatic transmission - Google Patents

Abstract

PURPOSE:To reduce the length of a shaft largely in an automatic transmission where the prescribed element of an epicyclic gear speed change mechanism is connected to a clutch, brake and a one-way clutch which are power transmitting route switching elements. CONSTITUTION:The clutch hub 41 of a directly connected clutch 24 which is connected between the sun gear 22a of the second epicyclic gear mechanism 22 and an input shaft 16, and the brake hub 51 of a coast brake 29 which is connected between the sun gear 22a and a transmission case 3 are formed in a double level in a diametrical direction on a common hub member 50. The second one-way clutch 27 connected between the sun gear 22a and a 3-4 brake 28 is disposed in a space 58 which is formed from the hub member 50 and a connecting member 57 for connecting the hub member 50 with the sun gear 22a of the second epicyclic gear mechanism 22 at the side of the second epicyclic gear mechanism 22, and the second one-way clutch 27, the directly-connected clutch 24 and the coast brake 29 are disposed so as to be piled up in a diametrical direction.

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 mounted on an automobile.

[0002]

2. Description of the Related Art A general automatic transmission is provided with a planetary gear mechanism and a power transmission path switching element including a clutch, a brake and a one-way clutch which is connected to the planetary gear mechanism and switches a power transmission state.

By the way, with the recent shift to FF in automobiles,
Since the engine is mounted horizontally on the vehicle body, it is required to shorten the axial length of the automatic transmission, and on the other hand, it is required to increase the number of gears.

Therefore, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2-38744, a main transmission composed mainly of an input shaft arranged on the same axis as the torque converter,
There has been proposed an automatic transmission including a sub transmission that is configured around a counter shaft that is arranged in parallel with the input shaft at a predetermined distance.

A clutch connected to the planetary gear mechanism,
Among brakes and one-way clutches, the clutch generally includes a plurality of friction plates between an inner peripheral side cylindrical clutch hub and an outer peripheral side cylindrical clutch drum. When pressed, the clutch is engaged thereby, and the clutch drum and the clutch hub rotate together.

Further, the brake is generally provided with a plurality of friction plates between an inner peripheral side cylindrical brake hub and an outer peripheral side cylindrical transmission case, and the friction plates are pressed by a hydraulic piston. By doing so, the brake is fastened and the brake hub is fixed to the transmission case.

[0007]

By the way, in order to cope with the tendency of the occupied space of the automatic transmission to be restricted due to the increase of the engine capacity, further reduction of the axial length is particularly required. For this reason, various attempts have been made to reduce the axial length, but it has been difficult to meet the above requirements.

In view of the above circumstances, it is an object of the present invention to propose a power transmission device which can significantly reduce the axial length of an automatic transmission.

[0009]

A power transmission device for an automatic transmission according to the present invention is a connecting member for connecting a predetermined element of a planetary gear mechanism and three power transmission path switching elements each including a clutch, a brake and a one-way clutch. With this configuration, the clutch hub of the clutch and the brake hub of the brake are formed in a radial staggered manner in a mode of forming a space on the side of the planetary gear mechanism, and the one-way clutch is arranged in the space. The three power transmission path switching elements are superposed in the radial direction.

[0010]

According to the present invention, the clutch, the brake and the one-way clutch, which are connected to the predetermined elements of the planetary gear mechanism, are overlapped in the radial direction, so that the axial length of the automatic transmission is significantly shortened. Therefore, it is possible to reduce the size of the automatic transmission.

[0011]

EXAMPLES Examples of the present invention will be described below.

As shown in the skeleton diagram of FIG. 1, an automatic transmission 1 for a front-wheel drive vehicle in which an engine is horizontally mounted according to this embodiment includes a torque converter 10 and a torque converter 10.
It has a main transmission 20 arranged on the same axis as the torque converter 10 and an auxiliary transmission 30 arranged on an axis parallel to these axes.

The torque converter 10 includes a pump 12 which is integral with a case 11 connected to the engine output shaft 2, and a turbine 13 which is arranged to face the pump 12 and is driven by the pump 12 through hydraulic oil. A stator 15 disposed between the pump 12 and the turbine 13 and supported by the transmission case 3 via a one-way clutch 14, and the turbine 13
Output shaft connected to the converter, that is, the automatic transmission 1
The input shaft 16 and a lockup clutch 17 that directly connects the input shaft 16 to the engine output shaft 2 via the case 11.

An oil pump 4 driven by the engine output shaft 2 via the torque converter 10 is arranged between the torque converter 10 and the main transmission 20.

As shown in the sectional view of FIG. 2, the main transmission 20 has a first planetary gear mechanism 21 arranged on the input shaft 16 closer to the torque converter 10 than the drive gear 5 described later. And a second planetary gear mechanism 22 arranged on the opposite side of the dive gear 5 from the torque converter 10 side. The input shaft 16 is a forward clutch.
23 and the sun gear 21a of the first planetary gear mechanism 21 and the sun gear 22a of the second planetary gear mechanism 22 via the direct coupling clutch 24, respectively. The ring gear 22b of the second planetary gear mechanism 22 is connected.

Further, the ring gear 21 of the first planetary gear mechanism 21.
The first one-way clutch is provided between b and the transmission case 3.
25 and the low reverse brake 26 are connected in parallel, and a second one-way clutch 27 and a 3-way clutch 27 are provided between the sun gear 22a of the second planetary gear mechanism 22 and the transmission case 3.
The four brakes 28 are connected in series, and a coast brake 29 for engine braking is connected in parallel with the four brakes 28. The pinion carrier 22c of the second planetary gear mechanism 22 is connected to the drive gear 5 that transmits power from the main transmission 20 to the sub transmission 30, and the drive gear 5 has a first
The pinion shaft 21d of the planetary gear mechanism 21 is integrally connected,
The drive gear 5 also serves as a pinion carrier of the first planetary gear mechanism 21.

With the main transmission 20 having such a structure, a forward low speed stage, a medium high speed stage, a high speed stage and a reverse stage can be obtained.

That is, first, when only the forward clutch 23 is engaged, the power from the input shaft 16 is transmitted via the forward clutch 23 to the sun gear 21 of the first planetary gear mechanism 21.
Since the ring gear 21b is fixed to the case 3 via the first one-way clutch 25 while being input to a, the rotation of the input shaft 16 is greatly reduced by the drive gear 5 which also serves as the pinion carrier of the first planetary gear mechanism 21. It will be decelerated by a ratio and output, and a low speed stage will be obtained by this.

When the 3-4 brake 28 is engaged from this low speed state, the sun gear 22 of the second planetary gear mechanism 22 is also engaged.
a is the second one-way clutch 27 and the 3-4 brake 28
The ring gear 22 of the second planetary gear mechanism 22 is fixed from the input shaft 16 via the forward clutch 23 and the sun gear 21a of the first planetary gear mechanism 21 by being fixed to the case 3 via the.
The power input to b is decelerated by the second planetary gear mechanism 22 at a reduction ratio smaller than the reduction ratio of the above low speed stage, and is output to the drive gear 5 from the pinion carrier 22c. Is obtained.

Further, when the direct coupling clutch 24 is engaged in this medium speed state, the power from the input shaft 16 causes the forward clutch 23 and the sun gear 21a of the first planetary gear mechanism 21 to operate.
At the same time as being input to the ring gear 22b of the second planetary gear mechanism 22 via the above, it is also input to the sun gear 22a of the second planetary gear mechanism 22 via the direct coupling clutch 24. Therefore, the entire second planetary gear mechanism 22 rotates integrally, and the pinion carrier 22c moves to the drive gear 5
A rotation equal to the rotation of the input shaft 16 is output to, so that a high speed stage (direct connection stage) is obtained.

When the forward clutch 23 is released and the direct coupling clutch 24 and the low reverse brake 26 are engaged, the power from the input shaft 16 is transmitted through the direct coupling clutch 24 to the sun gear of the second planetary gear mechanism 22. 22a and the ring gear 21b of the first planetary gear mechanism 21 is fixed to the case 3 via the low reverse brake 26, so that the planetary gear mechanisms 21 and 22 drive the drive gear 5 to the input shaft 16 of the input shaft 16. The rotation is reversed and output, and the reverse gear is obtained.

When decelerating at the low speed stage and the medium speed stage, the first and second one-way clutches 25 and 27 idle and the engine brake does not operate. However, in the engine brake range, In the low speed stage, the low reverse brake 26 in parallel with the first one-way clutch 25 is engaged, and in the middle speed stage, the second reverse brake 26 is engaged.
By connecting the coast brake 29 in parallel with the one-way clutch 27, the low speed stage and the medium speed stage in which the engine brakes operate are obtained.

On the other hand, as shown in the sectional view of FIG. 3, the auxiliary transmission 30 has a single third planetary gear provided on a counter shaft 35 rotatably supported by the case 3. A driven gear 6 having a mechanism 31 and constantly meshed with the drive gear 5 of the main transmission 20 is connected to the ring gear 31b of the third planetary gear mechanism 31, and the counter shaft 35
A direct coupling clutch 32 is connected between the sun gear 31a fixed to the above and the ring gear 31b, and a third one-way clutch 33 is provided between the sun gear 31a and the transmission case 3.
And the deceleration brake 34 are connected in parallel. And
The output gear 7 rotatably provided on the outer circumference of the counter shaft 35 is connected to the pinion carrier 31c of the third planetary gear mechanism 31, and the output gear 7 is connected to the left and right via a differential device 36 (see FIG. 3). Power is transmitted to the drive wheels (not shown) of the.

The sub-transmission 30 can shift the power input from the main transmission 20 via the drive gear 5 and the driven gear 6 into two forward speeds, a low speed stage and a high speed stage, and output it to the output gear 7. It is configured to be able to.

That is, in the state where the direct coupling clutch 32 is released, the counter shaft 35 is fixed to the transmission case 3 by the third one-way clutch 33 or the deceleration brake 34, and the sun gear 31a of the third planetary gear mechanism 31 is thereby fixed.
Is fixed, the power from the driven gear 6 input to the ring gear 31b of the third planetary gear mechanism 31 is decelerated and output from the pinion carrier 31c to the output gear 7, whereby a low speed stage is obtained. In this case, if the deceleration brake 34 is engaged, the engine brake operates as a unit of the auxiliary transmission 30.

When the direct coupling clutch 32 is engaged and the deceleration brake 34 is released, the ring gear 31b and the sun gear 31a of the third planetary gear mechanism 31 are directly coupled clutches.
By being coupled via 32 and counter shaft 35,
The power from the driven gear 6 is the pinion carrier 31c.
Is directly output to the output gear 7, whereby a high speed stage (direct connection stage) can be obtained.

In this way, the main transmission 20 can obtain three forward and one reverse gear stages, and the auxiliary transmission 30 can provide two high and low gear stages with respect to the output of the main transmission 20. Therefore, as a whole, the automatic transmission can obtain 6 shift stages for forward movement, and the reverse stage of the main transmission 20 and the deceleration brake 34 of the auxiliary transmission 30 can be engaged for reverse movement. By combining with the low speed stage, the reverse stage as a whole can be obtained. Further, in this embodiment, as the forward shift speed, a predetermined five speeds of the above six speeds are used.

Table 1 shows the operating states of the clutches and brakes at each of the five forward gears and one reverse gear. In addition, in Table 1, (◯) indicates that the engagement is performed only in the range for engine braking.

[0029]

[Table 1]

Next, the structure of the main transmission provided in the automatic transmission 1 according to this embodiment will be described in more detail with reference to the enlarged sectional views of FIGS. 4 and 5.

The first characteristic of the structure of the main transmission 20 is that the forward clutch 23, the low reverse brake 26 and the first one-way clutch 25, which are power transmission path switching means.
However, together with the first planetary gear mechanism 21, they are centrally arranged on the input side of the input shaft 16 with respect to the drive gear 5, that is, on the torque converter 10 side.

As is clear from Table 1, the forward clutch 23 is always engaged in the first to fifth speeds, and the power input from the torque converter 10 to the input shaft 16 is supplied to the first and second planetary gear mechanisms. Since it is a clutch that transmits to 21 and 22, it is necessary to transmit a large torque especially in the first and second gears having a large gear ratio, and the low reverse brake 26 is also used in the first and second gears having a large gear ratio and in reverse. Since the brake is used, it receives a large reaction force when it is engaged. Further, the first one-way clutch 25 is also locked in the 1st speed and the 2nd speed, so that it also receives a large reaction force.

Therefore, the forward clutch 23, the low reverse brake 26 and the first one-way clutch 25 are
A device having a larger torque transmission capacity or reaction force withstanding capacity than the other power transmission switching means is required, which inevitably has a large outer diameter.

Therefore, in the present embodiment, the power transmission path switching means having a large torque transmission capacity or reaction force withstanding capacity and the first planetary gear mechanism 21 connected to these means have a torque with a large outer diameter. By centrally arranging them adjacent to the converter 10, a sufficient occupied space is provided for the power transmission path switching means, and the drive gear 5 arranged in the central portion of the input shaft 16 of the main transmission 20 in the axial direction. With respect to the torque converter 10 side (on the left side of the drive gear 5 in FIGS. 1 and 2) with respect to the torque converter 10 side, the power transmission path switching means which may have a relatively small torque transmission capacity or reaction force resistance capacity, that is, a direct connection. Clutch 24,3-
By arranging the 4 brake 28, the coast brake 29, and the second one-way clutch 27, the outer diameter of the portion of the main transmission 20 on the left side of the drive gear 5 is reduced, and the automatic transmission 1 as a whole is downsized. ing.

Further, by disposing the forward clutch 23 inside the low reverse brake 26 in the radial direction, the axial length of the main transmission 20 is also shortened.

On the other hand, as is clear from FIG. 3, the auxiliary transmission 30 has the structure of the automatic transmission 1 as a whole, by reversing the size relationship of the outer diameter from that of the main transmission 20 described above. The miniaturization of

That is, in the sub transmission 30, the third planetary gear mechanism 31 having a relatively small outer diameter is arranged on the right side of the driven gear 6, that is, on the input side of the input shaft 16, and each element of the third planetary gear mechanism 31 is arranged. The direct coupling clutch 32, the deceleration brake 34, and the third one-way clutch 33, which have a larger outer diameter than the planetary gear mechanism 31, are connected to the left side of the driven gear 6 to reduce the size of the entire automatic transmission 1. I am trying to

The second characteristic of the main transmission 20 is, as is apparent from the enlarged sectional view of FIG. 4, the second one-way clutch 27 connected to the sun gear 22a of the second planetary gear mechanism 22.
And a direct coupling clutch 24 connected between the sun gear 22a and the input shaft 16, and a coast brake 29 connected between the second one-way clutch 27 and the transmission case 3.
And the point where they are superposed in the radial direction.

That is, the coast brake 29 is 3-4.
Along with the brake 28, the second planetary gear mechanism 22 is axially arranged outside in the radial direction, and the direct coupling clutch 24 is arranged on the side of the second planetary gear mechanism 22 (on the left side in the figure). By disposing 27 at the inner side of the direct coupling clutch 24 in the radial direction, the axial length of the main transmission 20 is significantly shortened.

More specifically, the clutch hub 41 of the direct coupling clutch 24 and the brake hub 51 of the coast brake 29 are formed in different steps on a single hub member 50.
At the left end (in FIG. 4) of 50, the left end of a connecting member 52 that is integrally provided with the sun gear 22a of the second planetary gear mechanism 22 on the outer periphery of the right end and extends to the left is fixed. The connecting member 52 has an outer periphery of a portion extending leftward from the sun gear 22a as an inner race 27a of the second one-way clutch 27, and further extends radially outward from the left end of the inner race 27a to form the hub. Connected to the left end of the member 50, between the connecting member 50 and the clutch hub 41 portion of the hub member 50,
A space 58 is formed on the left side of the second planetary gear mechanism 22. The second one-way clutch 27 is housed in the space 58.

Therefore, the second one-way clutch 27,
One end of each of the direct coupling clutch 24 and the coast brake 29 has a sun gear 22a of the second planetary gear mechanism 22 via a connecting member 57 and a hub member 50 connected to the connecting member 57.
Will be linked to.

The direct coupling clutch 24 includes a clutch drum 40 connected to the input shaft 16 via a boss portion 40a, a clutch hub 41 integrally formed with a part of the hub member 50, and a clutch drum 40. A plurality of friction plates 42, 43 alternately engaged between the spline 40b formed on the circumference and the spline 41a formed on the outer circumference of the clutch hub 41, respectively.
And a hydraulic piston 44 disposed on the left side of the friction plates 42, 43 in the clutch drum 40 for engaging the friction plates 42, 43 when a fastening pressure is applied, and an annular partition wall fixed to the boss portion 40a.
45 and a plurality of return springs 46 that are compressed between the partition wall 45 and the hydraulic piston 44 to urge the piston 44 in the anti-fastening direction.

The inner circumference of the hydraulic piston 44 has the partition wall 45.
Is in sliding contact with a seal member 47 mounted on the outer periphery of the piston, and between the hydraulic piston 44 and the partition wall 45, an oil chamber behind the piston 44 is provided.
An oil chamber 49 having substantially the same diameter as 48 is formed. This oil chamber 49
Is open to the atmosphere through an oil passage 45a formed in the partition wall 45. Due to the existence of this oil chamber 49, the hydraulic pressure due to the centrifugal force that acts on the working oil in the oil chamber 48 behind the piston with rotation Minutes are offset and the oil chamber 48 is removed from the hydraulic circuit (not shown).
The piston 44 is configured to be operated only by the hydraulic pressure of the hydraulic oil supplied to.

Further, the coast brake 29 has a plurality of frictions which are alternately engaged with the splines 3a formed in the transmission case 3 and the splines of the brake hub 51 integrally formed with a part of the hub member 50. The plates 52, 53 and the friction plates 52, 53 are arranged on the left side of the friction plates 52, 53, and when the hydraulic pressure is applied, the friction plates 52, 53
23 and the hydraulic piston 54 for fastening the hydraulic piston 54
2 and a plurality of return springs 56 (FIG. 2) that are compressed between the hydraulic retainer 55 and the spring retainer 55 fixed to the case portion 3b that accommodates the piston 54 and urge the piston 54 in the anti-fastening direction. (See) and. The hydraulic piston 54 extends through the spring retainer 55 and extends toward the friction plates 52, 53.
It is equipped with.

The 3-4 brake 28 includes a brake hub 61,
A plurality of friction plates 62, 63 alternately engaged with the splines formed on the outer periphery of the brake hub 61 and the splines 3a formed on the inner periphery of the transmission case 3, respectively, and the friction plates 62, 63,
A hydraulic piston 64 arranged on the right side of 63 for fastening the friction plates 62, 63 when a fastening pressure acts, a spring retainer 65 fixedly mounted on the transmission case 3, and a spring retainer 65 for this.
It is constituted by a return spring compressed between 65 and the hydraulic piston 64.

The brake hub 61 is connected to the outer race 27b of the second one-way clutch 27 housed in the space 58 between the clutch hub 41 of the direct coupling clutch 24 and the connecting member 57, and along the hub member 50. Has been extended.

On the other hand, the forward clutch 23, as shown in FIG. 5, is connected to the input shaft 16 and has a clutch drum 70 having a spline 70a formed on the inner peripheral surface thereof and the sun gear of the first planetary gear mechanism 21. 21a and a clutch hub 71 having splines 71a formed on the outer peripheral surface thereof, and the spline 71a of the clutch hub 71 and the clutch drum 70.
, 70a alternately engaged with a plurality of friction plates 72, 7
3 and the right side of the friction plates 72 and 73 (in FIG. 5) in the clutch drum 70, and when the fastening pressure acts, the friction plates
Hydraulic piston 74 for engaging 72 and 73, and clutch drum
A spring retainer 75 fixed to the 70 and a plurality of return springs 76 arranged between the spring retainer 75 and the hydraulic piston 74 to urge the piston 74 in the anti-fastening direction. Above hydraulic piston 74
Is provided with a drift-on ball 78 that opens and closes the exhaust pressure passage 77 in order to prevent a clutch disengagement failure that occurs due to the centrifugal force that acts on the hydraulic oil as it rotates.

The low reverse brake 26, which is superposed on the outside of the forward clutch 23, has a brake hub 81 connected to the ring gear 21b of the first planetary gear mechanism 21.
And a plurality of friction plates 82, 83 engaged alternately with the splines 81a formed on the outer peripheral surface of the brake hub 81 and the splines 3c formed on the inner peripheral surface of the transmission case 3, respectively.
And a hydraulic piston 84 arranged on the right side of the friction plates 82, 83 (in FIG. 5) for engaging the friction plates 82, 83 when a fastening pressure acts, and a spring retainer 85 fixed to the case 3.
And a plurality of return springs 86 (see FIG. 2) that are compressed between the spring retainer 85 and the hydraulic piston 84 to urge the piston 84 in the anti-fastening direction. The hydraulic piston 84 is a spring retainer 85.
An extending portion 84a that penetrates through the plate and extends toward the friction plates 82 and 83 is integrally provided.

The third characteristic of the main transmission 20 is, as is apparent from FIG. 5, that the first planetary gear mechanism 21 is located on the right side of the drive gear 5 provided coaxially with the input shaft 16 (see FIG. 5). In (1), the pinion shaft 21d of the first planetary gear mechanism 21 is integrally connected to the drive gear 5, and thereby the pinion carrier is omitted. Limiting the number of parts and main transmission
The shaft length is shortened by 20.

The drive gear 5 is integrally provided with a boss portion 5a extending in the axial direction, and the outer periphery of the boss portion 5a is
A partition wall 3d formed integrally with the case 3 is rotatably and axially immovably supported by a double tapered bearing 88. With this configuration, the support rigidity of the first planetary gear mechanism 21 is improved.

Further, the first planetary gear mechanism 21 and the first one-way clutch 25 are radially overlapped, and the ring gear 21b of the first planetary gear mechanism 21 is attached to the inner peripheral surface of the inner race 25a of the first one-way clutch 25. Has been formed. An oil sump 90 is formed on the side of the first planetary gear mechanism 21 (on the right side in FIG. 5), and the oil that communicates between the oil sump 90 and the outer peripheral surface of the inner race 25a of the first one-way clutch 25 is connected. Since the passage 89 is formed in the inner race 25a, the supply of lubricating oil to the first one-way clutch 25 is ensured.

The outer periphery of the outer race 25b of the first one-way clutch 25 is spline-engaged with the inner peripheral surface of the transmission case 3.

Next, the structure of the auxiliary transmission 30 in the automatic transmission 1 according to this embodiment will be described in more detail with reference to FIG.

The feature of this auxiliary transmission 30 is that the deceleration brake 34
Friction plates 92, 93 and a hydraulic piston 94 for fastening the friction plates 92, 93 are arranged on opposite sides of each other with respect to the third one-way clutch 33, and the hydraulic piston 94 is connected to the third one-way clutch 33. The outer race 97 is partially penetrated at a plurality of positions in the circumferential direction.

The deceleration brake 34 uses the clutch drum 100 of the direct coupling clutch 32 connected to the counter shaft 35 as a clutch hub, and is formed on the spline 3e formed on the transmission case 3 and the outer periphery of the clutch drum 100. The plurality of friction plates 92 and 93, which are alternately engaged with the splines 91a, are arranged on the opposite side of the one-way clutch 33 from the friction plates 92 and 93 side, and the friction plates 92 and 93 are fastened when hydraulic pressure is applied. And a spring retainer 95 fixed to the case portion 3f forming the inward sliding contact surface of the hydraulic piston 94, and the spring retainer 95 and the hydraulic piston 94. It is composed of a return spring 96.

On the other hand, a third one-way clutch interposed between the hydraulic piston 94 of the deceleration brake 34 and the friction plates 92, 93.
As shown in FIG. 7, the outer peripheral surface of the outer race 97 of 33 is engaged with the spline 3e formed on the inner peripheral surface of the transmission case 3 to restrict the movement of the outer race 97 in the rotational direction. A plurality of engaging portions 97a and a plurality of wide grooves 97b formed between the engaging portions 97a.

The hydraulic piston 94 is provided with a plurality of extending portions 94a penetrating the groove 97b of the outer race 97 and extending toward the friction plates 92, 93. An engaging portion 94b, which engages with the spline 3e of the case 3 and restricts the movement of the piston 94 in the rotational direction, is provided at the tip of the extending portion 94a so as to project radially outward.

As described above, the auxiliary transmission 30 in this embodiment is
Is a deceleration brake that occupies a relatively large radial space
Since the hydraulic piston 94 of 34 and the third one-way clutch 33 are arranged in parallel, and the friction plates 92 and 93, which occupy a relatively small space in the radial direction, are arranged on the sides thereof, a compact layout can be realized, and the friction plates can be realized. It is possible to dispose the friction plates 102 and 103 of the direct coupling clutch 32 on the radially inner side of 92 and 93.

Further, the spring retainer 95 is integrally formed with a positioning member 98 for axially positioning the outer race 97 of the one-way clutch 33, whereby the outer race 97 is positioned with respect to the transmission case 3. In this case, two snap rings that are usually used can be stopped.

Further, on the back of the hydraulic piston 94 for engaging the deceleration brake 34, a first hydraulic chamber 98a on the inner peripheral side having a large pressure receiving area and a second hydraulic chamber 98b on the outer peripheral side having a small pressure receiving area are concentrically arranged. It is provided in. And these hydraulic chambers 98a
, 98b, when the same fastening pressure is introduced into the first hydraulic chamber 98a, the fastening pressure is introduced into the second hydraulic chamber 98a.
A larger fastening pressure can be obtained than that introduced in b.

The direct coupling clutch 32 includes the clutch drum 100 connected to the counter shaft 35 to which the sun gear 31a of the third planetary gear mechanism 31 is fixed, the clutch hub 101 fixed to the driven gear 6, and the clutch drum 100. A plurality of splines 100a formed on the peripheral surface and a plurality of splines 101a formed on the outer peripheral surface of the clutch hub 101 are alternately engaged with and disposed inside the friction plates 92, 93 of the reduction brake 34 in the radial direction. The friction plates 102, 103 and these friction plates 102,
A large-diameter first piston 104a having a large pressure receiving area, which is arranged on one side (left side in FIG. 6) of 103, and the first piston 104a.
Second small-diameter piston 104b having a small pressure-receiving area, which is arranged on the back of the spring retainer 10 fixed to the output shaft 35.
5, the spring retainer 105 and the first piston 104a
It is constituted by a return spring 106 which is compacted between and.

Then, the first hydraulic chamber 108a at the back of the first piston 104a to which the fastening pressure is introduced from the oil passage 107, and the second back of the second piston 104b to which the fastening pressure is introduced from the oil passage 109 (see FIG. 3). A hydraulic chamber 108b is provided, and these hydraulic chambers 108a, 10a
When the same fastening pressure is introduced to 8b, the first hydraulic chamber 108a
In the case of being introduced into the second hydraulic chamber 108b, a larger fastening pressure can be obtained than in the case of being introduced into the second hydraulic chamber 108b.

Further, in the present embodiment, the friction plate 10 of the direct coupling clutch 32 that is engaged at a plurality of shift stages having different transmission torques.
2, 103 and the friction plates 92, 93 of the deceleration brake 34,
At the gear position where the transmission torque is large, the hydraulic pressure is introduced into the first hydraulic chamber 108a or 98a having a large pressure receiving area so that the friction plate 102
, 103 or 92, 93 are fastened to each other, and the second hydraulic chamber 108b or
Since the hydraulic pressure is introduced to 98b to fasten the friction plates 102, 103 or 92, 93, there is no need for control means such as changing the line pressure, and an excess or deficiency depending on the transmission torque of the gear stage can be achieved. No fastening pressure can be obtained.

As is clear from the above description, according to this embodiment, the sun gear 22a of the second planetary gear mechanism 22 and the input shaft
The clutch hub 41 of the direct coupling clutch 24 connected to the 16 and the brake hub of the coast brake 29 connected to the sun gear 22a and the transmission case 3.
51 are formed on the common hub member 50 in a stepped manner in the radial direction, and by the hub member 50 and a connecting member 57 that connects the hub member 50 to the sun gear 22a of the second planetary gear mechanism 22, 2 Space 58 formed on the side of the planetary gear mechanism 22
Is provided with a second one-way clutch 27 connected between the sun gear 22a and the 3-4 brake 28, and the second one-way clutch 27, the direct coupling clutch 24, and the coast brake 29 are arranged to overlap each other in the radial direction. As a result, the axial length of the main transmission 20 can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a skeleton diagram of an automatic transmission according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a structure of a main transmission of the automatic transmission.

FIG. 3 is a sectional view showing a structure of an auxiliary transmission in the same automatic transmission.

FIG. 4 is a partially enlarged sectional view of the main transmission of FIG.

5 is a partially enlarged sectional view of the main transmission of FIG.

6 is a partially enlarged sectional view of the auxiliary transmission of FIG.

FIG. 7 is a sectional view taken along line VII-VII of FIG.

[Explanation of symbols]

 10 Torque converter 11 Input shaft 20 Main transmission 21 First planetary gear mechanism 22 Second planetary gear mechanism 23 Forward clutch 24 Direct coupling clutch 25 First one-way clutch 26 Low reverse brake 27 Second one-way clutch 28 3-4 Brake 30 Auxiliary shift Machine 31 3rd planetary gear mechanism 32 Direct coupling clutch 33 3rd one-way clutch 34 Deceleration brake 35 Counter shaft

Claims (2)

[Claims] 1. An automatic transmission comprising a planetary gear speed change mechanism, wherein a predetermined element of the planetary gear speed change mechanism is connected to a clutch, a brake and a one-way clutch which are power transmission path switching elements. Of the clutch hub of the clutch and the brake hub of the brake are formed in such a manner that a space is formed laterally of the planetary gear mechanism by a connecting member that connects the predetermined element and the three power transmission path switching elements. A power transmission device for an automatic transmission, characterized in that the power transmission device is formed in different steps in the direction, the one-way clutch is arranged in the space, and the three power transmission path switching elements are radially overlapped. 2. The power transmission of an automatic transmission according to claim 1, wherein a brake for connecting and disconnecting the one-way clutch and the transmission case is provided on an outer periphery of the planetary gear mechanism. apparatus.