JP2933748B2 - Friction fastening device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction fastening device used for switching between transmission and release of rotation of an automatic transmission of an automobile.

[0002]

2. Description of the Related Art Conventionally, as a friction fastening device, for example, a device described in Japanese Utility Model Application Laid-Open No. 61-116236 has been known.

[0003] In this conventional apparatus, a frictional fastening member comprising a drive plate and a driven plate alternately arranged, a piston for pressing the frictional fastening member in an axial direction, and a piston opposed to the piston with the frictional fastening member interposed therebetween. And a dish plate (elastic member) provided between the friction fastening member and the piston or between the friction fastening member and the stopper. The drive plate and the driven plate serving as the friction fastening members are spline-coupled to the inner and outer circumferences of the drum, respectively, and are mounted so as to be movable in the axial direction.

[0004] When the conventional frictional fastening device is engaged, the change in the engagement capacity and the change in the rotation speed of the input shaft have characteristics as shown in the figure.

[0005]

However, in the above-described conventional frictional fastening device, as shown in the characteristic diagram of the engagement capacity and the input rotation speed in FIG. 7, the frictional engagement is performed between t1 and t2. In the period when the fastening capacity of the device is not enough for the input torque, the shift phenomenon (change in the number of revolutions) does not occur at all, but since the friction has started, the frictional heat is generated and the temperature of the friction material becomes Rise.

That is, if the period from t1 to t2 is long, the following problems occur. The time lag at which the shift phenomenon starts becomes longer, and the feeling deteriorates.

This time (the period from t1 to t2) varies depending on the temperature and the like, and it is difficult to improve the control accuracy.

[0008] Heat generation is large, and the durability of the friction fastening member is shortened. In addition, the frictional fastening members may come into contact with each other due to the elastic force provided by the dish plate, and drag may occur. In this case, the calorific value is further increased.

As described above, if the period from t1 to t2 is long, various problems occur. In particular, in a structure in which the dish plate is arranged between the piston and the friction fastening member, the friction fastening member starts fastening. If the dish plate is not elastically deformed before the fastening, the fastening is not started and the time from t1 to t2 becomes longer. On the other hand, even in a structure in which the dish plate is provided on the opposite side of the friction fastening member from the piston, a fastening state in which a sufficient fastening capacity is obtained is not obtained until the dish plate is completely deformed. In order to obtain a sufficient fastening capacity at an early stage, it is necessary to increase the elastic force of the dish plate. However, as described above, even when the () piston is not pressed, the dish plate is not pressed. Is applied to the friction fastening member, and the friction fastening member is always fastened.

The present invention has been made in view of the above-mentioned problems, and it is intended to improve the shift feeling by shortening the time lag from the start of the fastening operation to the start of the shift phenomenon. At the same time, it is an object of the present invention to provide a friction fastening device capable of improving the control accuracy while keeping the time lag constant, and further suppressing the heat generation of the friction fastening member and improving the durability.

[0011]

According to the present invention, a retaining plate for restricting axial movement by a predetermined amount or more is provided at a position opposite to a piston with a friction fastening member interposed therebetween, and a preload is applied to the retaining plate. By giving, the above-mentioned object was achieved.

That is, in the friction fastening device of the present invention, a piston for pressing a plurality of friction fastening members in the axial direction is provided at a position opposite to the piston with respect to the friction fastening member, and is moved in the axial direction. A retaining plate movably supported, a first stopper disposed at a position opposite to the frictional fastening member with the retaining plate interposed therebetween so as to regulate an axial movement amount of the retaining plate to a predetermined amount; A second stopper disposed at a position on the side of the frictional fastening member, and a retaining plate of the frictional fastening member and the first stopper;
An elastic member disposed between the stopper and a stopper, the elastic member providing a preload to the retaining plate;
The stopper is provided at a position for separating the first friction surface and the retaining plate when the piston is not pressed.

[0013]

When the piston is not pressed, the retaining plate is preloaded by an elastic body, but the movement of the retaining plate in the direction of the friction fastening member is restricted by the second stopper. Therefore, the elastic force of the elastic body is not input to the friction fastening member. Therefore, no drag occurs in the friction fastening member due to the elastic force of the elastic body.

When the piston starts the pressing operation, the pressing force of the piston is first input to the friction fastening member, and the friction fastening member starts fastening. Then, immediately when the friction surface of the friction fastening member comes into contact with the retaining plate, a preload of the elastic body is input to the friction fastening member, and a high pressing force acts on the friction fastening member. Therefore,
Fastening capacity sufficient to cause a shift phenomenon can be obtained in a short time. Further, the time until the preload is obtained is constant without being affected by the temperature, the variation in the elastic force of the elastic body, and the like.

By the way, if the piston continues to press after the friction surface of the friction fastening member comes into contact with the retaining plate, the retaining plate moves in the axial direction within a range where the elastic body is elastically deformed. During this time, the fastening capacity gradually increases. When the movement of the retaining plate is restricted by the first stopper, the reaction force causes the piston pressing force to rise based only on the piston pressing force characteristic, and the fastening capacity of the friction fastening member to be increased accordingly. Rise. Thereby, the final desired fastening force is obtained at the same time that the friction fastening member is completely fastened.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. In describing the embodiment, an example in which the present invention is applied to a clutch device of an automatic transmission will be described.

FIG. 1 is a sectional view showing a main part of a clutch device according to a first embodiment of the present invention. In the drawings, reference numerals 1 and 2 show alternately arranged drive plates and driven plates as friction fastening members. I have. The drive plate 1 is connected to a drum connected to an input shaft (not shown) by a spline, and is supported movably in the axial direction. On the other hand, the driven plate 2 is similarly connected to a drum 3 provided on the outer periphery of the drum (not shown) by a spline 4, and is supported so as to be movable in the axial direction.

A piston 5 for pressing the drive plate 1 and the driven plate 2 in the axial direction is provided inside the drum 3. The piston 5 forms a cylinder chamber 6 with the drum 3.

A retaining plate 7 is provided on the inner periphery of the drum 3 at a position opposite to the piston 5 with the drive plate 1 and the driven plate 2 interposed therebetween. This retaining plate 7 also
It is supported by a spline 4 so as to be movable in the axial direction. On the inner periphery of the drum 3, at a position opposite to the piston 5 with the retaining plate 7 interposed therebetween,
A snap ring 8 as a first stopper is provided, while a step 4a as a second stopper is formed at a position on the piston side in the middle of the spline 4 so that the amount of axial movement of the retaining plate 7 is limited. It is regulated to quantitative.
The stepped portion 4a is located at such a position that the first friction surface 1a, which is the friction surface of the drive plate 1 disposed closest to the retaining plate 7, is not brought into contact with the retaining plate 7. Is set to

A dish plate 9 is provided between the retaining plate 7 and the snap ring 8. The dish plate 9 is dimensioned to elastically deform when placed at this position and to provide a preload to the snap ring 8 and the retaining plate 7. That is, the axial dimension of the dish plate 9 is formed to be larger than the distance h between the retaining plate 7 and the snap ring 8 when the retaining plate 7 is brought into contact with the step portion 4a. It is designed to be elastically deformed. The preload is set to a value substantially equal to the pressing force required for the drive-driven plates 1 and 2 to be engaged with a capacity at which a shift phenomenon occurs in the automatic transmission.

Next, the operation of the embodiment will be described.

(When the piston 5 is not pressed) When the piston 5 is not pressed, the retaining plate 7 and the snap ring 8 are preloaded by the dish plate 9, and the retaining plate 7 is moved to the step 4a. Has been pressed against. In this case, the retaining plate 7 and the first friction surface 1a are determined based on the position of the step 4a.
And the drive-driven plates 1,
No. 2 does not receive this preload. Therefore, no drag occurs between the drive-driven plates 1 and 2 due to the preload, and no accompanying heat generation occurs.

(During Piston Pressing Operation) When the piston 5 starts the pressing operation, the piston 5 makes a stroke to bring each drive plate 1 into contact with each driven plate 2 and start the fastening operation. As soon as the first friction surface 1a comes into contact with the retaining plate 7 due to this pressing force, the preload by the dish plate 9 is input, and the fastening capacity between the drive-driven plates 1 and 2 rises sharply, and the speed change A sufficient fastening capacity to cause the phenomenon is obtained in a short time. And furthermore, piston 5
When the pressing operation continues, the retaining plate 7 moves in the direction of the snap ring 8 while elastically deforming the dish plate 9, and the pressing force of the piston 5 gradually increases. When the dish plate 9 is flattened and the movement of the retaining plate 7 is restricted by the snap ring 8, the rate of increase of the pressing force increases, and the fastening capacity between the drive-driven plates 1 and 2 is reduced. A sufficient fastening capacity is reached in which no slippage occurs between the two.

This effect is illustrated in the pressing force characteristic diagram of FIG. 2 and FIG.
In FIG. 2, the stroke range a of the piston 5 is changed from the non-fastened state in which the drive-driven plates 1 and 2 are completely separated from each other. Abuts and the first
The range of the stroke until the friction surface 1 a comes into contact with the retaining plate 7 and the pressing force is transmitted to the retaining plate 7 is shown. In this range a, no substantial pressing force is generated on both the drive-driven plates 1 and 2. A period corresponding to this range is a period indicated by t0 to t1 in FIG. 3, and at this time, no fastening capacity is generated between both the drive-driven plates 1 and 2.

Next, in the stroke range b in FIG. 2, the pressing force of the piston 5 exceeds the preload of the dish plate 9 to deform the dish plate 9 and move the retaining plate 7 until it is regulated by the snap ring 8. In this case, at the moment when the first friction surface 1a and the retaining plate 7 come into contact with each other, the pressing force of the piston 5 against the drive-driven plates 1 and 2 immediately rises due to the preload reaction force. The pressing force gradually increases in accordance with the movement of the retaining plate 7, and further rises rapidly when the movement of the retaining plate 7 is restricted.

In FIG. 3, this corresponds to t 1 to t 1.
This is a period indicated by t6, and a period from t1 to t4 is a period in which the fastening capacity sharply increases due to the preload. The period between t1 and t2 is a period in which the shifting phenomenon does not occur and the capacity is insufficient, and the subsequent period between t2 and t4 is a period in which the shifting capacity has the shifting phenomenon. And t4 ~
The period of t5 is a period in which the pressing force of the piston 5 exceeds the preload and moves the retaining plate 7 in the axial direction. The period from t5 to t6 is a period in which the fastening capacity increases in accordance with an increase in the pressing force of the piston 5 after the dish plate 9 has a flat plate shape and the movement of the retaining plate 7 is restricted.

In the apparatus of this embodiment, as shown in the characteristic diagram of FIG. 3, when the first friction surface 1a and the retaining plate 7 come into contact with each other, the coupling capacity immediately rises immediately, and a shift phenomenon occurs in a short time. The fastening capacity is obtained. Therefore, the time lag (the period from t0 to t2) from the start of the shift operation to the occurrence of the shift phenomenon is reduced, and the effect that a good shift feeling can be obtained is obtained.
It is possible to obtain an effect that it is possible to prevent wasteful fastening between the drive-driven plates 1 and 2 and to suppress heat generation and improve durability. In addition, the time lag (t
0 to t2), there is no member that is deformed by the pressing force of the piston 5, and this time lag can be kept constant without being affected by temperature, elasticity variation, etc. Can be improved.

In addition, when the preload is applied to the retaining plate 7, the spline 4 is provided with a stepped portion 4a as a second stopper. The effect of preventing the occurrence of is obtained. Further, in this embodiment, since the step portion 4a is used as a second stopper without adding a component, the number of assembling steps does not increase.

Further, due to the presence of the dish plate 9, the change in the engagement capacity after the shift phenomenon occurs is smoothed (period t2 to t5), thereby preventing the shift shock and improving the shift quality. I have.

Next, another embodiment will be described.
In the description of the other embodiments, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Only the differences from the first embodiment will be described. In addition, about action,
A description of the same operations as in the first embodiment will be omitted.

FIG. 4 is a sectional view showing an essential part of a second embodiment of the present invention, and FIG. 5 is a sectional view showing an essential part of a third embodiment of the present invention. .

In the second and third embodiments, the spline 4
The stopper rings 4d, 4e are formed in the grooves 4b, 4c so as to be engageable with the retaining plate 7.
Are provided to constitute the second stopper. The difference between the second embodiment and the third embodiment is the position where the grooves 4b and 4c and the stopper rings 4d and 4e are set and the shape of the retaining plate 7.

FIG. 6 is a sectional view showing a main part of a fourth embodiment of the present invention.

In the fourth embodiment, two retaining plates, a first retaining plate 71 and a second retaining plate 72, are provided between the first and second retaining plates 71, 72. A dish plate 9 as an elastic body is provided. 4f is a groove, 4f
g is a stopper ring.

Although the embodiment of the present invention has been described with reference to the drawings, the specific configuration is not limited to this embodiment. For example, in the embodiment, the dish plate is provided as the elastic body, but other means such as a coil spring may be used as long as the dish plate has elastic force. Further, in the embodiment, the example in which the present invention is applied to the clutch device of the automatic transmission has been described, but the present invention may be applied to other devices such as industrial equipment other than the automatic transmission.

[0036]

As described above, in the friction fastening device of the present invention, the preload is applied to the retaining plate disposed on the opposite side of the friction fastening member from the piston, and at the same time, the piston is not pressed. Since the retaining plate is provided with a second stopper for preventing the preload from being input to the friction fastening member during operation, when the piston is pressed, the pressing force of the piston is transmitted to the retaining plate. As a result, a shift phenomenon can be caused by a preload being input immediately, thereby shortening the time lag from the start of the pressing operation of the piston to the occurrence of the shift phenomenon, thereby improving the shift feeling. In addition to the effect that the heat generation of the friction fastening member can be suppressed and the durability can be improved, There is an advantage that it is possible to improve the control accuracy by constant time lag. Moreover, while such an effect is obtained, during the non-pressing operation of the piston, the preload of the retaining plate can be prevented from being input to the friction fastening member by the second stopper, thereby preventing heat generation due to drag. The effect that durability can be improved is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a friction fastening device according to a first embodiment of the present invention.

FIG. 2 is a pressure characteristic diagram of a piston of the first embodiment.

FIG. 3 is a characteristic diagram of an input shaft rotation speed and a fastening capacity of the device of the first embodiment.

FIG. 4 is a sectional view showing a main part of a friction fastening device according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing a main part of a friction fastening device according to a third embodiment of the present invention.

FIG. 6 is a sectional view showing a main part of a friction fastening device according to a fourth embodiment of the present invention.

FIG. 7 is a characteristic diagram of an input shaft rotation speed and a fastening capacity according to the related art.

[Explanation of symbols]

 Reference Signs List 1 drive plate (friction fastening member) 2 driven plate (friction fastening member) 4a step (second stopper) 4d stopper ring (second stopper) 4e stopper ring (second stopper) 4g stopper ring (second stopper) 5 piston Reference Signs List 7 retaining plate 8 snap ring (first stopper) 9 dish plate (elastic body) 71 first retaining plate 72 second retaining plate

Claims (1)

(57) [Claims] 1. A piston for pressing a plurality of frictional fastening members in an axial direction, and a retaining member disposed at a position opposite to the piston with respect to the frictional fastening members and supported to be movable in an axial direction. A plate and a first stopper disposed at a position opposite to the friction fastening member with the retaining plate interposed therebetween so as to restrict the axial movement amount of the retaining plate to a predetermined amount; A second stopper provided, and an elastic body disposed between the retaining plate and the first stopper among the friction fastening members, and configured to apply a preload to the retaining plate, wherein the second stopper is provided. Is disposed at a position for separating the first friction surface and the retaining plate when the piston is not pressed.