JP2000170792A - Automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the load applied to a friction plate and to suppress the fatigue of the friction plate by providing an exciting mechanism on a spline groove, and exciting the projection of the friction plate in the opposite direction to the locking direction of a one-way clutch. SOLUTION: A recess 23d serving as a coupling section is formed nearly at the center of a projection 23c. The recess 23d has a shape couplable with the lug 31a of a plate spring 31. The projection 23c is positioned by using the exciting force of the plate spring 31 and a pair of coupling sections 23d, 31a, i.e., the projection 23c is excited to the side section of a spline groove 25c. The projection 23c is excited in the opposite direction to locking direction A to have a large clearance (b), and projections of a driven plate 23b and a drive plate can be suppressed from being applied with a large load, thus the fatigue of the driven plate 23b and the drive plate can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission having a multi-plate friction engagement device and a one-way clutch.

[0002]

2. Description of the Related Art An automatic transmission used in an automobile or the like has a planetary gear composed of a sun gear, a ring gear, a pinion gear, and the like. Switching of the characteristics of the power transmission mechanism, that is, shifting, is performed by engaging or disengaging a friction engagement device such as a multi-plate clutch or a multi-plate brake. Generally, these multi-plate friction engagement devices have a structure in which drive plates, which are power input side plates, and driven plates, which are power output side plates, are alternately arranged. Since the drive plate and the driven plate are sandwiched by the pressure from the pressure plate, power can be transmitted between these plates.

By the way, many of such automatic transmissions use a one-way clutch in addition to the multi-plate frictional engagement element. For example, in a sports shift in which the shift of the automatic transmission is manually performed, engagement control may be performed such that the one-way clutch is locked and the multi-plate brake is also engaged (for example, at the time of starting the first speed).

FIG. 17 is a sectional view showing the structure of a conventional multi-plate type frictional engagement element in which a one-way clutch is mounted on a hub side. A large number of sprags 73 are arranged between the inner race 71 and the hub (outer race) 72, and these members constitute a one-way clutch. When the hub 72 rotates in the locking direction A (clockwise direction in the figure) in a state where the sprags 73 are arranged as illustrated (for example, at the time of first-speed acceleration), the sprags 73 rise and the inner race 71 is rotated.
And the hub 72 are locked, and the rotation of the hub 72 is locked. However, when the hub 72 rotates in the direction opposite to the locking direction A (for example, at the time of first-speed deceleration), the sprag 73 lies down and the hub 72 can rotate. On the other hand, hub 72
Drive plates 75 and driven plates 76 are alternately arranged between the transmission case 74 and the front surface to the back surface of the paper surface of FIG. The drive plate 75 is spline-fitted to the hub 72, and the driven plate 76 is spline-fitted to the transmission case 74. The hub 72, the transmission case 74, and the friction plates 75 and 76 constitute a brake. In addition,
The inner race 71 is fixed to the mission case 74.

In the above-described configuration, consider a case where the hub 72 rotates in the locking direction A in a state where the brake is engaged. When the hub 72 rotates in the locking direction A, the sprag 73 starts to rise. One-way clutch,
If the sprag 73 does not rise, an action of restricting (that is, locking) the rotation of the hub 72 does not occur. In other words, the regulating force of the one-way clutch is
Is caused by the rotation of the hub 72 by a rotation amount corresponding to the rising portion of. Therefore, the rotation of the hub 72 is regulated by the generation of the regulating force of either the one-way clutch or the brake. As a result, the braking force may act before the one-way clutch force is generated.

That is, in FIG. 17, when the hub 72 rotates in the locking direction A, the clearance a (so-called play) in the fitting area between the hub 72 and the drive plate 75 is blocked, and the drive plate 75 also rotates in the locking direction A. At this point, since the drive plate 75 and the driven plate 76 are in the fastening state, the driven plate 76 also rotates in the locking direction A. Accordingly, the clearance b, which is a play in the fitting area between the driven plate 76 and the transmission case 74, is also blocked, so that the protrusion of the driven plate 76 contacts the side of the spline groove.
Therefore, the torque of the hub 72 and the plates 75, 76
Load according to the degree of fastening of the friction plates 75 and 76
Will join the protrusion. When the accelerator is fully depressed, for example, during full development, the load becomes extremely large, and the driven plate 76 may become fatigued and its durability may be reduced. Considering that such a load is frequently applied, an approach of improving the durability and strength of the friction plate itself by using a friction plate made of an expensive material leads to an increase in the cost of the automatic transmission. It is not preferable.

Although it is not intended to address the above problem, Japanese Patent Publication No. 3-78495 (Japanese Patent Laid-Open No. 59-208)
231) discloses a one-way clutch in which urging means for constantly pressing the outer race in the locking direction of the one-way clutch is disposed between the outer race and the fixing member. By providing such biasing means,
When the one-way clutch is reversed from free to locked, the impact between the outer race and the fixed member is prevented, and the occurrence of noise is prevented. However, this technique is not intended at all with respect to the above-described problems arising from the relationship with the friction engagement device, particularly the relationship between the rise of the one-way clutch and the engagement of the friction engagement device. The configuration is also different. The most characteristic difference in the configuration is the direction in which the urging means is urged, and the details thereof will be clearly understood from the following description.

[0008]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, an object of the present invention is to effectively reduce the load applied to a friction plate and suppress the fatigue of the friction plate.

[0009]

In order to solve the above-mentioned problems, a first invention is to provide a multi-plate friction engagement device in which a plurality of friction plates are arranged between a hub and a drum; In an automatic transmission having a one-way clutch provided on one member side, a first plate formed with a plurality of circumferentially formed projections fitted into spline grooves formed in a hub; and The protrusions fitted to the spline grooves formed on the drum are fitted with the second plate formed in a plurality of circumferential directions, and the spline grooves formed on the drum and the protrusions of the second plate are fitted. An automatic transmission having an urging means provided in a mating fitting area and for urging a projection of the second plate in the fitting area in a direction opposite to a locking direction in which the one-way clutch operates. .

In a second aspect of the present invention, there is provided a multi-disc type friction engagement device in which a plurality of friction plates are arranged between a hub and a drum, and a one-way clutch provided on one member side of the hub or the drum. In the automatic transmission having the spline grooves formed on the hub, the protrusions fit into the first plate formed in the circumferential direction and the spline grooves formed on the drum, respectively. A plurality of projecting portions are provided in a fitting region where a plurality of circumferentially formed second plates, a spline groove formed in the hub, and the projecting portions of the first plate fit together, The first in
And an urging means for urging the projection of the plate in the direction opposite to the locking direction in which the one-way clutch acts.

In the first and second aspects of the present invention, the projection in the fitting area is provided with the first engagement portion, and the biasing means engages with the first engagement portion. A plate-like elastic member having a second engaging portion having a shape and disposed at the bottom of the spline groove;
The first clearance formed between the side of the one-way clutch on the locking direction side of the one-way clutch and the projection in the spline groove in a state where the second engagement part and the second engagement part are engaged with each other. It is preferable that the protrusion is located at a position larger than a second clearance formed between a side portion of the groove in a direction opposite to the locking direction and the protrusion.

In this case, the elastic member is configured such that the first clearance is wider than the second clearance when the first engagement portion and the second engagement portion are not engaged. It is desirable to bias the protrusion in the direction.

In the first and second aspects of the present invention, the biasing means may be an elastic member attached to a side of the spline groove and biasing the projection in a direction opposite to the locking direction. This elastic member may be, for example, a compression spring provided on a side part on the locking direction side, or a tension spring provided on a side part on the side opposite to the locking direction.

Further, in the first and second inventions, the one-way clutch has an inner race and a plurality of sprags disposed between the inner race and the hub. Only at the inner race and the hub, and the urging means urges the projection in the direction opposite to the locking direction, so that the spline groove is between the side of the locking direction side and the projection. Create a clearance, the clearance is
It is desirable that the displacement is larger than the displacement of the protrusion corresponding to the rising of the sprag.

[0015]

In such a configuration, the urging means urges the projection of the friction plate in a direction opposite to the locking direction of the one-way clutch by its elastic action. As a result, the biasing means acts to increase the clearance between the projection and the side of the spline groove on the locking direction side. Therefore, even if the protrusion is displaced corresponding to the rotation amount until the one-way clutch operates, the possibility that the protrusion contacts the spline groove is reduced because the clearance is widened. Further, even if the contacts are in contact, the load is reduced because the load is only partially received.

[0016]

FIG. 1 is a diagram showing a schematic structure of an automatic transmission as an example. The driving force from the crankshaft 9 of the engine is transmitted to the turbine shaft 11 via the torque converter 10. A turbine shaft 11, which is an input shaft of the transmission, is connected to a sun gear of the rear planetary gear 2. On the other hand, a reduction drive shaft 12 which is an output shaft of the transmission is connected to a ring gear of the front planetary gear 1 and a planetary carrier of the rear planetary gear 2. Each member (sun gear, planetary carrier, ring gear) in the two planetary gears 1 and 2
Three multi-plate clutches (reverse clutch 3, high clutch 5, low clutch 6), two multi-plate brakes (2 & 4
Brake 4, low & reverse brake 7), and low one-way clutch 8. These engagement elements (clutch, brake) are selectively engaged or disengaged so as to achieve a gear position determined according to various parameters such as a throttle opening. By selectively switching the power transmission or the power transmission path in this manner, this automatic transmission can perform four forward speeds and one reverse speed.

FIG. 2 is a table showing the relationship between the shift position and the engagement state of the engagement element in the transmission of FIG. In this table, a circle indicates that the corresponding engaging element is engaged, and a blank indicates that it is released.
Further, the mark ◎ indicates that the engagement is performed only during the corresponding driving. The speed change in this transmission is basically
This is achieved by a clutch-to-clutch shift (shift in which the first-stage engagement element is released and the second-stage engagement element is engaged).
Only the shift between the second speed and the second speed uses a one-way clutch-to-clutch shift.

Here, the low & reverse brake 7 is engaged when the select position is in the R (reverse) range, in the first speed of the SPORT shift, and when the select position is in the first speed.
There are three cases of speed. Therefore, for example, when the shift is changed to the SPORT shift in the first speed state of the D (drive) range, the low & reverse brake 7 is engaged. Since the input torque in the acceleration direction at the first speed is received by the low one-way clutch 8, there is basically no need to engage the low & reverse brake 7. However, only the one-way clutch 8 cannot receive the input torque in the deceleration direction (idling direction of the one-way clutch 8). Therefore, only the range where engine braking is required, that is, one range and SPORT shift,
The low & reverse brake 7 is engaged in the first gear. Here, the SPORT shift is performed by manually operating a shift knob in a sports gate provided separately from a gate corresponding to a normal shift pattern (P-R-N-D-2-1) to shift up. And a semi-automatic mode for downshifting. Note that the shift by the SPORT shift may be executed by operating an up / down switch provided on the steering wheel.

In such an automatic transmission, for example, SP
When the low one-way clutch 8 operates as in the case of the first speed start in the ORT shift, the play in the spline fitting portion of the low & reverse brake 7, that is, the clearance starts to be blocked before the operation occurs. At this time, if the play of the low & reverse brake 7 is eliminated before the low one-way clutch 8 is actuated, a load corresponding to the degree of acceleration is applied to the protrusion of the friction plate constituting the low & reverse brake 7. Therefore, in the present embodiment, an urging mechanism that actively increases the clearance is provided to suppress such a load from being applied to the friction plate.

FIG. 3 is a perspective view of essential parts in which main parts constituting a frictional engagement device which is the low & reverse brake 7 are developed. A low clutch drum 20 serving as a power transmission member is integrally provided with a hub 20a for the low & reverse brake 7, and a low one-way clutch 8 is mounted inside the hub 20a. A spline groove is formed on the inner periphery of a portion of the transmission case that accommodates the low & reverse brake 7, and a groove for attaching a snap ring is formed at one end of the spline groove. Between the hub 20a and the spline groove of the transmission case, a retaining ring 22, friction plates 23a and 23b,
And the dish plate 24 are assembled. Here, two types of friction plates having different shapes, that is, a drive plate 23a and a driven plate 23b
Are arranged alternately. The drive plate 23a has a plurality of protrusions formed at regular intervals along its inner periphery, and the driven plate 23b has a plurality of protrusions formed at regular intervals along its outer periphery. The protrusion of the drive plate 23a is spline-fitted with the spline groove of the hub 20a. On the other hand, the projection of the driven plate 23b is spline-fitted with a spline groove provided on the transmission case side. The width of these spline grooves is
Since the projections are formed slightly wider than the widths of the projections to be engaged, a clearance corresponding to the difference between these widths is formed in the fitting region. With such a configuration, the friction plates 23a and 23b can move only in the axial direction.

FIG. 4 is a side sectional view showing a main part of the friction engagement device of FIG. This drawing shows only the lower half of the frictional engagement device based on the hollow reduction drive shaft 26, and substantially the same configuration actually exists in the upper half. FIG. 5 is a cross-sectional view taken along the line II shown in FIG. 4 (the upper half configuration is also clearly shown). The driven plate 23b is spline-fitted with a spline groove of the transmission case 25 existing on a concentric circle of the hub 20a. The piston 27 moves according to the oil pressure supplied from an oil passage (not shown), and presses the dish plate 24 toward the retaining plate 22. Thereby, the drive plate 23a and the driven plate 23
b, these plates 23a, 23b
It is possible to transmit power between them. A large number of sprags 29 are disposed between the inner race 28 and the hub 20a which are arranged concentrically.
The low one-way clutch 8 is constituted by 8, 20a and 29. The inner race 28 is fastened to the transmission case 25 by bolts. Therefore, the rotation of the hub 20a in the locking direction A shown in FIG.
Regulated by low one-way clutch. here,
The “locking direction” refers to a rotation stopping direction that connects the inner race and the hub that is the outer race, in other words, a rotation direction in which the sprag rises.

In a specific fitting area 30 (see FIG. 5) of the plurality of fitting areas in which the driven plate 23b and the transmission case 25 are spline-fitted, a plate spring 31 as an urging mechanism is provided. It is installed. The plate spring 31 is an elastic member provided at the bottom of the fitting area 30 and extending in a bridge shape along the fitting area 30 (see FIG. 4). Although the details of the plate spring 31 will be described later, the elasticity of the driven plate 23
The protrusion b (the protrusion engaged with the fitting area 30) is constantly urged in the direction opposite to the lock direction A. The plate-shaped spring 31 is inserted through the opening 25a of the spline groove in the transmission case 25, and the transmission case 2
5 is in contact with the wall 25b. Then, after the insertion of the plate-shaped spring 31, the other members 3 close to the opening 25a.
2 (for example, a piston retainer of 2 & 4 brake) is attached. Therefore, the inserted plate spring 31 does not fall out of the fitting area 30.

FIG. 6 is a plan view of the plate spring 31 in this embodiment, and FIG. 7 is a sectional view taken along the line AA of FIG. FIG. 8 is a view for explaining a state of the plate-shaped spring 31 in the fitting area 30. 6 and 7
As shown in (1), the plate spring 31 is slightly longer than the axial length (extended length) of the spline groove 25c formed in the transmission case 25, and has a bridge shape. On the surface of the plate-shaped spring 31 which is arranged to face the projection 23c of the driven plate 23b, a projection 31a extending in the axial direction is provided. Here, the convex portion 31a which is the engaging portion is provided with the spline groove 25c.
In the width direction of FIG. 6 is offset to one side (the lower side in FIG. 6). One end of the plate-shaped spring 31 is bent toward the protrusion 23c to form a hooking surface 31b. When the plate spring 31 is displaced in the axial direction by a predetermined amount or more in the inserted state of the plate spring 31, the locking surface 31b comes into contact with the member 32 shown in FIG. 4, so that the plate spring 31 does not fall off.

On the other hand, the other end of the plate spring 31 is also bent in the same direction as the hooking surface 31b to form a stopper surface 31c. With the protrusion 23c engaged with the spline groove 25c, the plate spring 31 is inserted from the opening 25a into the clearance (a gap formed between the protrusion 23c and the bottom of the spline groove 25c). Then, the stopper surface 31c is moved to the wall 25b of the transmission case 25.
Abut. Further, by inserting the plate-shaped spring 31, an urging force is generated so that the plate-shaped spring 31 bends toward the protrusion 23c.

On the other hand, a recess 23d, which is an engaging portion, is formed substantially at the center of the projection 23c. This recess 23d is
It has a shape that can be engaged with the projection 31 a of the plate spring 31. In this embodiment, the projection 23c is positioned by using the urging force of the plate spring 31 and the pair of engagement portions 23d and 31a. That is,
The projection 23c is biased toward the side of the spline groove 25c (the side opposite to the locking direction A of the low one-way clutch).

FIG. 9 is a front sectional view showing a state in which the plate-shaped spring 31 is mounted in each state. As shown in FIG. 7A, the recess 23d on the driven plate 23b side
The clearance b formed between the projection 23c and the side of the spline groove 25c on the locking direction A side becomes maximum when the and the projection 31a of the plate spring 31 are engaged. Here, assuming that the width of the spline groove 25c is w1 and the width of the projection 23c is w2, the maximum clearance bmax is w1−w2. On the other hand, in a state in which the engaging portion is not engaged as shown in FIG. 2B (that is, a state in which an external force is applied to the driven plate 23b and the protrusion 23c is displaced in the locking direction A), the plate-shaped spring 31 is not attached. The force acts to return the concave portion 23d to the position of the convex portion 31a.

When such a plate-like spring 31 is not provided, the projection 2 of each driven plate 23b is provided.
Since 3d is located at random within the range of the width w1, the clearance b also takes a random value within the range of 0 ≦ b ≦ bmax. However, as in the present embodiment, the projections 23 of all the driven plates 23b
d are provided, and these concave portions 23 d are engaged with the convex portions 31 a of the plate spring 31. Therefore,
By the action of the plate-shaped spring 31, an action is exerted such that the clearance b becomes the maximum clearance bmax for all the driven plates 23b.

As described above, the projection 23c is urged in the direction opposite to the locking direction A by the plate-shaped spring 31, and the clearance b is made large, so that the projection of the driven plate 23b or the drive plate 23a becomes large. The addition of a load can be suppressed. 17, when the hub 72 rotates in the locking direction A, the locking action of the low one-way clutch is performed by a displacement corresponding to the rising amount of the sprag 73.
It does not occur if does not rotate. With the rotation of the hub 72, the clearance a between the hub 72 and the drive plate 75 is blocked, and the drive plate 75 starts to rotate. At this time,
When the drive plate 75 and the driven plate 76 are fastened, the driven plate 76 also rotates. As a result, the clearance b existing between the side of the spline groove of the transmission case 74 and the projection of the driven plate 76 is blocked. However, the urging mechanism 31 as in the present embodiment is used.
Is used, the maximum clearance bmax is
If the protrusion is greater than the displacement of the protrusion of the driven plate 76 corresponding to the rising amount of No. 3, the protrusion does not contact the spline groove. Further, even if the contact is made, the load received by the protrusion is reduced to such an extent that it receives a part of the total load.

Therefore, it is possible to effectively reduce a large load applied to the spline fitting area of the driven plate and the transmission case and the spline fitting area of the drive plate and the hub. As a result, fatigue of the driven plate and the drive plate can be suppressed. In particular, since the drive plate is formed thinner than the driven plate, fatigue on the drive plate side has been a problem. By applying this embodiment, such a problem can be solved. Further, since it is possible to avoid the necessity of using a plate material having high durability and strength, the cost of the automatic transmission does not increase. Further, there is an effect that the contact sound of the friction plate, that is, the contact sound between the plates in a free state caused by vibration or the like can be effectively reduced.

(Second Embodiment) FIG. 10 is a side view of a plate spring according to a second embodiment, and FIG. 11 is a top view of the plate spring of FIG. The plate spring 41 has a structure in which a plate is bent in a V-shape. One end of the plate-shaped spring 41 is bent at a right angle to form a hook portion 41a, and the other end is also slightly bent. With such a configuration, the plate spring in this embodiment functions as a compression spring.

FIG. 12 is a view for explaining the state of the plate spring 41 in the fitting area 30. The projection 23c of the driven plate 23b is
The plate-shaped spring 41 is inserted in the clearance in the locking direction A of the low one-way clutch in a state of being engaged with the spline groove 25c. As in the case of the first embodiment, the engaging portion 41a of the plate spring 41
Is brought into contact with a member such as a piston retainer of the 2 & 4 brake attached in the vicinity, so that the plate-shaped spring 41 is
Are prevented from falling out of the spline groove 25c. Note that the arrows shown in the figure merely indicate the positional relationship between the spline grooves 25c and the plate springs 41, and do not indicate the direction in which the plate springs 41 are inserted.

In such a configuration, the spline grooves 2
The elasticity of the plate-shaped spring 41 provided on the side of the lock direction A of 5c acts so as to constantly urge the protrusion 23c in the direction opposite to the lock direction A.
As a result, the protrusion 23c is in contact with the side opposite to the lock direction A. Therefore, the side of the spline groove 25c on the locking direction A side and the protrusion 23
The clearance b formed between c can be set to the above-mentioned maximum clearance bmax.

As described above, in the plate-shaped spring 41, the clearance b in the locking direction A is the maximum clearance bmax.
It is urging to become. Therefore, the maximum clearance bmax is the protrusion 23c corresponding to the rising amount of the sprag.
Is larger than the displacement amount, the protrusion 23c contacts the spline groove 25c to prevent a large load from being applied to the friction plate. Therefore, the same effects as those described in the first embodiment are obtained.

(Third Embodiment) FIG. 13 is a top view of a biasing mechanism 51 according to a third embodiment, and FIG.
It is a side view of the urging mechanism of No. 3. Also, FIG.
FIG. The biasing mechanism 51 includes the engaging portion 5
1a, a pair of tension coil springs 51b, and a mounting portion 51c. The engaging portion 51a has a U-shaped cross section, and the distance between the opposing wall portions is
Since it is formed slightly larger than the width of the protrusion c of b,
The protrusion 23c can be engaged with the engagement portion 51a. The engaging portion 51a and the mounting portion 51c are connected via a tension coil spring 51b. Therefore, the engagement portion 5
The mounting portion 5a is provided by the elastic action of the spring 51b.
It is constantly urged toward 1c side.

FIG. 16 is a view for explaining the state of the urging mechanism 51 in the fitting area 30. In a state where the projection 23c of the driven plate 23b is engaged with the spline groove 25c of the transmission case 25, the urging mechanism 51 is inserted into a clearance (clearance between the side and the bottom) existing therebetween. Here, the attachment portion 51c is attached to a cutout groove 25f formed at the bottom of the spline groove 25c on the side opposite to the locking direction A. Note that the arrows shown in the same figure merely indicate the positional relationship among the spline groove 25c, the protrusion 23c, and the urging mechanism 51, and indicate the mounting direction, similarly to the meaning of the arrow in FIG. Not necessarily.

In such a configuration, the urging mechanism 51 provided in the fitting area 30 pushes the projection 23c engaged in the engaging portion 51a in the opposite direction to the lock direction A by the urging force of the spring 51b. In the direction of. As a result, the protrusion 23c is in contact with the side opposite to the lock direction A. Therefore, the side of the spline groove 25c on the locking direction A side and the protrusion 23c
The clearance b formed between them becomes the above-described maximum clearance bmax.

Accordingly, for the same reason as described in the first and second embodiments, the load applied to the friction plate can be effectively reduced, so that the fatigue of the friction plate can be suppressed.

The urging mechanisms 31, 41, 51, such as plate springs, described in the first to third embodiments are merely examples, and may be provided by using an elastic member such as a coil spring or rubber. Even when a biasing mechanism is configured, it is included in the applicable range of the present invention. What is important here is that the urging mechanism urges the protrusion in the direction opposite to the locking direction A by utilizing the elastic action of the mechanism.

The first to third embodiments have described the case where the biasing mechanism is attached to the driven plate and the spline fitting area of the transmission case (drum). However, for the purpose of the present invention, it is also possible to provide the biasing mechanism in the spline fitting area of the drive plate and the hub. Referring to FIG. 17, the clearance a in the fitting region of the hub 72 and the drive plate 75 is widened by the urging mechanism of the present invention. The hub 7 corresponds to the rising of the sprag 73.
Even if 2 is displaced, the amount of displacement of the protruding portion of the driven plate 76 can be reduced by the extent that the clearance a is widened. As a result, it is possible to suppress the protrusion of the driven plate 76 from contacting the spline groove of the transmission case 74. The one-way clutch need not always be provided on the hub side, and the present invention can be applied to a structure in which a rotatable drum is used instead of the transmission case and the one-way clutch is provided on the drum side. It is possible to apply.

Further, the automatic transmission shown in FIGS. 1 and 2 merely shows one example to which the present invention can be applied, and it goes without saying that the present invention can be applied to an automatic transmission having another structure. Further, it is naturally possible to apply the present invention to a friction engagement device other than the low & reverse brake. As apparent from the description in the present specification, the present invention can be applied to various friction engagement devices that are controlled in cooperation with a one-way clutch.

[0041]

As described above, according to the present invention, a biasing mechanism such as a spring is provided in the spline groove, and the projection of the friction plate is biased by the biasing mechanism in a direction opposite to the locking direction of the one-way clutch. I'm going. Thereby, the clearance formed between the side of the spline groove on the locking direction side and the projection can be increased. Therefore, even when the protrusion of the friction plate is displaced by an amount corresponding to the rise of the sprag of the one-way clutch, the contact of the protrusion of the friction plate with the spline groove can be effectively suppressed. Therefore, the application of an excessive load to the protrusion of the friction plate can be reduced, so that the fatigue of the friction plate can be suppressed and the decrease in the durability of the friction plate can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic structure of an automatic transmission as an example.

FIG. 2 is a table showing a relationship between a shift position and an engagement state of an engagement element in the automatic transmission of FIG. 1;

FIG. 3 is an essential part perspective view in which main parts constituting the friction engagement device are developed.

FIG. 4 is a side sectional view showing a main part of the friction engagement device of FIG. 3;

FIG. 5 is a sectional view taken along line II of FIG. 4;

FIG. 6 is a plan view of a plate spring according to the first embodiment.

FIG. 7 is a sectional view taken along line AA of FIG. 6;

FIG. 8 is a view for explaining a state of a plate spring in a fitting region.

FIG. 9 is a front sectional view showing a state in which a plate spring is mounted, according to a state;

FIG. 10 is a side view of a plate spring according to the second embodiment.

FIG. 11 is a top view of the plate spring of FIG. 10;

FIG. 12 is a view for explaining a state of a plate spring in a fitting region.

FIG. 13 is a top view of an urging mechanism according to a third embodiment.

FIG. 14 is a side view of the urging mechanism of FIG.

FIG. 15 is a sectional view taken along line BB of FIG. 13;

FIG. 16 is a view for explaining a state of a biasing mechanism in a fitting region.

FIG. 17 is a cross-sectional view showing the structure of a conventional multi-plate friction engagement element in which a one-way clutch is provided on a hub side.

[Explanation of symbols]

1 Front planetary gear, 2 Rear planetary gear, 3 reverse clutch, 4 2 & 4 brake, 5 high clutch, 6 low clutch, 7 low & reverse brake, 8 low one-way clutch, 9 crankshaft, 1
0 torque converter, 11 turbine shaft,
12 reduction drive shaft, 20 low clutch drum, 20a hub, 21 snap ring, 22 retaining plate, 23a
Drive plate, 23b driven plate,
24 dish plate, 25 mission case, 26 reduction drive shaft, 27 biston, 28 inner race, 29
Sprag, 30 mating area, 31
Plate spring, 32 other members, 41 plate spring, 51 biasing mechanism, 71 inner race, 72 outer race, 73
Sprag, 74 mission case,
75 drive plate, 76 driven plate

Claims (8)

[Claims] 1. An automatic transmission having a multi-plate friction engagement device in which a plurality of friction plates are arranged between a hub and a drum, and a one-way clutch provided on one member side of the hub or the drum. In the above, the protrusion fitted to each of the spline grooves formed in the hub is fitted to the first plate formed in a plurality of circumferential directions and the spline grooves formed in the drum, respectively. A plurality of protrusions are provided in a fitting area where a plurality of circumferentially formed second plates, and the spline grooves formed in the drum and the protrusions of the second plate are fitted;
An automatic transmission, comprising: urging means for urging the protrusion of the second plate in the fitting area in a direction opposite to a locking direction in which the one-way clutch operates. 2. An automatic transmission having a multi-plate friction engagement device having a plurality of friction plates arranged between a hub and a drum, and a one-way clutch provided on one of the members of the hub or the drum. In the above, the protrusion fitted to each of the spline grooves formed in the hub is fitted to the first plate formed in a plurality of circumferential directions and the spline grooves formed in the drum, respectively. A plurality of protrusions are provided in a fitting region where a plurality of circumferentially formed second plates, the spline grooves formed in the hub, and the protrusions of the first plate are fitted; The protrusion of the first plate in the fitting area,
An automatic transmission having biasing means for biasing in a direction opposite to a lock direction in which the one-way clutch operates. A first protrusion provided in the fitting area;
The urging means has a second engaging portion having a shape engaging with the first engaging portion, and is disposed at a bottom of the spline groove. A plate-like elastic member, wherein the elastic member is in the lock direction side of the one-way clutch in the spline groove in a state where the first engagement portion and the second engagement portion are engaged. The first clearance formed between the side portion of the and the protrusion,
The protrusion is located at a position larger than a second clearance formed between a side portion of the spline groove in a direction opposite to the locking direction and the protrusion. The automatic transmission according to claim 1 or 2, wherein 4. The elastic member according to claim 1, wherein the first clearance is greater than the second clearance when the first engagement portion and the second engagement portion are not engaged. The automatic transmission according to claim 3, wherein the protrusion is urged in a direction to increase the width. 5. An apparatus according to claim 1, wherein said urging means is an elastic member attached to a side portion of said spline groove to urge said projection in a direction opposite to said locking direction.
Or the automatic transmission according to 2. 6. The automatic transmission according to claim 5, wherein the elastic member is a compression spring provided on the side of the lock direction. 7. The automatic transmission according to claim 5, wherein said elastic member has a tension spring provided on said side portion opposite to said locking direction. 8. The one-way clutch has an inner race and a plurality of sprags disposed between the inner race and the hub, and only when the sprag stands up in the lock direction, only in the lock direction. The inner race and the hub are locked, and the urging means urges the projection in a direction opposite to the locking direction, thereby causing the side of the spline groove on the locking direction side to project from the projection. 3. The automatic transmission according to claim 1, wherein a clearance is generated between the protrusion and the protrusion, and the clearance is larger than a displacement amount of the protrusion corresponding to a rising amount of the sprag. 4.