JP2003035324A - Friction engagement device - Google Patents

Abstract

(57) Abstract: Provided is a friction engagement device that does not rotate a snap ring that holds a return spring at low cost. SOLUTION: An engagement groove 66 with which a friction plate 67 is engaged.
A friction member having a large-diameter cylindrical body 16 formed with a small-diameter cylindrical body 37 and a small-diameter cylindrical body 37 which is disposed inside the large-diameter cylindrical body 16 so as to be relatively rotatable and has an engagement groove 65 with which a friction plate 69 is engaged. A cylinder 73 mounted on the large-diameter cylinder 16.
, A piston 74 for applying a pressing force to the friction plates 67 and 69, a snap ring 80 having a notch formed in part and engaged with the large-diameter cylinder 16, and a piston 7.
4, and a return spring 77 for applying a spring force in a direction to return the piston 74. The large-diameter cylindrical body 16 has a fixed ring 82 that is prevented from rotating. The fixed ring 82 is disposed between the snap ring 80 and the return spring 77, and does not transmit rotation to the snap ring 80.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction engagement device incorporated in a power transmission system such as an automatic transmission for a vehicle to constitute a clutch or a brake.

[0002]

2. Description of the Related Art A power transmission system for transmitting engine output to driving wheels is composed of various devices such as a starting clutch, a transmission, a propulsion shaft, and a final reduction gear. The automatic transmission that automatically shifts according to the running state of the vehicle includes a planetary gear type automatic transmission that has a planetary gear etc. as a speed change mechanism and can switch to a predetermined gear according to the running state. , And a continuously variable transmission (CVT) that sets the gear ratio in a stepless manner according to the running state.

A friction engagement device having a plurality of annular friction plates is incorporated in an automatic transmission in order to select a power transmission path and set a shift speed. In the friction engagement device in which the friction plate is mounted between the large diameter clutch drum and the small diameter clutch hub arranged inside the clutch engagement device, when the friction plate is engaged, the clutch drum and the clutch hub are fastened. It transmits rotational power and is called a clutch. On the other hand, a friction engagement device in which a friction plate is mounted between a fixed large-diameter cylinder body such as a transmission case and a small-diameter brake hub arranged inside the cylinder is used when the friction plate is engaged. The hub will be fixed and is called the brake.

The continuously variable transmission is provided with a forward / reverse switching device for switching the rotational power from the starting device between a forward direction and a reverse direction. The forward / backward switching device changes the power rotation direction of the planetary gear mechanism. A clutch and brake are provided for switching. In a power transmission system of a four-wheel drive vehicle, a center differential device is used to distribute the driving force to the front wheels and the rear wheels. Some center differential devices also incorporate a friction engagement device. .

The friction engagement device has a piston and a plunger that are hydraulically operated to bring the friction plate into the engagement state, and the piston is brought into the engagement state when the friction plate is pressed in the axial direction. On the other hand, when releasing the hydraulic pressure of the piston and releasing the engagement state of the friction plate, a return spring is arranged in front of the piston to push the piston back, and one end of the return spring contacts the piston and The end abuts the snap ring via the retainer. The snap ring is made of an annular spring material, a part of which is cut away, and is contracted and incorporated in an annular groove formed on the inner peripheral surface of the drum, and has a spring force that expands in the radial direction.

The friction plates are mounted in engagement grooves formed in the hub and drum cylinders respectively, and when pressed, they slide in the axial direction and come into pressure contact, so that there is a gap between the engagement groove and the friction plate. Is provided with a sliding gap. Therefore, when the friction plate is engaged by the piston when the friction engagement device is fastened, the friction plate is displaced and rotated relative to the cylindrical body by the sliding gap. This rotational force is transmitted to the snap ring via the piston and the return spring.

At this time, when the rotational force exceeds the spring force of the snap ring, the snap ring rotates and slides in the groove,
Foreign matter such as metal powder may be generated from the sliding surface. Further, when burrs or burrs are generated on the snap ring, the rotational force may act to narrow the gap of the snap ring and reduce the diameter of the snap ring. If the amount of contraction of the snap ring increases, the snap ring may fall out of the groove.

In order to improve such a problem associated with the transmission of the rotational force of the snap ring, a friction engagement device for preventing the rotation of the snap ring by using a snap ring having a high tension, for example, Japanese Patent Laid-Open No. 2000-84751. As disclosed in the publication, a friction engagement device has been developed in which a snap-stop projection is formed on a snap ring to prevent the snap ring from rotating.

[0009]

In the case of a snap ring having a high tension, a snap ring having a tension higher than a required function and formed with a rotation stop has a limited mounting position in the circumferential direction. Therefore, in the assembly work of the power transmission system, the workability of assembling the snap ring is deteriorated, which leads to an increase in the number of work steps. In addition, since it is necessary to use a snap ring having a function beyond the original function of restricting the movement of the return spring in the axial direction, the price is also high.

An object of the present invention is to provide a friction engagement device which does not rotate a snap ring at low cost.

[0011]

SUMMARY OF THE INVENTION A friction engagement device according to the present invention comprises a large-diameter cylinder having an inner peripheral surface on which engagement grooves for engaging a plurality of friction plates are formed, and an inside of the large-diameter cylinder. And a small-diameter cylindrical body having engaging grooves for engaging a plurality of friction plates formed on an outer peripheral surface thereof, the cylinder being attached to the large-diameter cylindrical body. A piston for applying a pressing force to the friction plate, and a snap ring engaged with the large-diameter cylindrical body with a notch formed in a part thereof and the piston, and the piston is attached to the piston. It has a spring member that applies a spring force in a returning direction, and a stop portion that is provided in the piston and that engages with an engagement groove of the large-diameter cylindrical body.

The frictional engagement device of the present invention has a large-diameter cylindrical body having engagement grooves formed on the inner peripheral surface for engaging a plurality of friction plates, and is relatively rotatably disposed inside the large-diameter cylindrical body. A friction engagement device having an engagement groove with which a plurality of friction plates engage and a small diameter cylinder formed on an outer peripheral surface thereof, the friction engagement device being incorporated in a cylinder attached to the large diameter cylinder. It is mounted between a piston that applies a pressing force to the plate, a snap ring that is partially formed with a notch and is engaged with the large-diameter cylindrical body, and the piston, and a spring force is applied in the direction that returns the piston. An additional spring member and a guide pin fixed to the cylinder and axially slidably fitted in a guide hole formed in the piston are featured.

In the friction engagement device of the present invention, a large-diameter cylinder having engagement grooves formed on the inner peripheral surface for engaging a plurality of friction plates, and a relatively rotatable arrangement inside the large-diameter cylinder. A friction engagement device having an engagement groove with which a plurality of friction plates engage and a small diameter cylinder formed on an outer peripheral surface thereof, the friction engagement device being incorporated in a cylinder attached to the large diameter cylinder. It is mounted between a piston that applies a pressing force to the plate, a snap ring that is partially formed with a notch and is engaged with the large-diameter cylindrical body, and the piston, and a spring force is applied in the direction that returns the piston. It has a spring member to add and a fixing ring arranged between the snap ring and the spring member and fixed to the large-diameter cylindrical body.

According to the present invention, the piston is provided with the stopper portion, and the stopper portion is engaged with the engagement groove of the large-diameter cylindrical body.
Since the rotational force generated from the friction plate is not transmitted to the snap ring and there is no need to add a rotation prevention function to the snap ring, a friction engagement device that prevents the snap ring from rotating at a low cost is provided. Can be provided.

According to the present invention, the guide pin is provided in the cylinder fixed to the large-diameter cylindrical body, and the guide pin is slidably fitted in the guide hole of the piston so that the rotational force generated from the friction plate is generated. Since it is not transmitted to the snap ring and it is not necessary to add a rotation preventing function to the snap ring, it is possible to provide a friction engagement device in which the snap ring does not rotate at low cost.

According to the present invention, by providing the fixing ring fixed to the large-diameter cylinder between the snap ring and the spring member, the rotational force generated from the friction plate is not transmitted to the snap ring. In addition, since it is not necessary to add a rotation preventing function to the snap ring, it is possible to provide a friction engagement device in which the snap ring does not rotate at low cost.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a skeleton diagram showing an automatic transmission having a plurality of friction engagement devices according to an embodiment of the present invention. The automatic transmission has an input shaft 11 connected to the engine 10 and an output shaft 13 provided on a concentric shaft of the input shaft 11 and connected to a center differential device 12, and the center differential device 12 is connected to the center differential device 12. It has a front wheel output shaft 14 and a rear wheel output shaft 15 that connect the drive wheels. The input shaft 11, the output shaft 13, the front wheel output shaft 14, and the rear wheel output shaft 15 are incorporated in a transmission case 16 facing the traveling direction of the vehicle, and this automatic transmission is a four-wheel vehicle arranged vertically. It is applied to vehicles for driving.

A torque converter 18 is connected to a crankshaft 17 of the engine 10, and an input shaft 11 is connected to a turbine shaft 19 which is an output shaft of the torque converter 18. A rear sun gear 20 is fixed to an end portion of the input shaft 11, and a plurality of rear pinion gears 22 that are rotatably supported by a rear carrier 21 are meshed with the rear sun gear 20 and are mounted radially outward of the rear sun gear 20. Further, a rear ring gear 23 having teeth on its inner peripheral surface is mounted on the outer side of the rear sun gear 20 so as to mesh with the rear pinion gear 22, and the rear sun gear 20 and the rear ring gear 23 are connected via the rear pinion gear 22. There is. In this way, the rear sun gear 20, the rear ring gear 23, and the rear pinion gear 22 constitute the rear planetary gear train 24.

The front sun gear 2 is attached to the input shaft 11.
5 is rotatably provided, and a plurality of front pinion gears 27, which are rotatably supported by a front carrier 26, are provided radially outward of the front sun gear 25.
It is installed by meshing with. Further, a front ring gear 28 having teeth on its inner peripheral surface is mounted on the outside of the front sun gear 25 in the radial direction so as to mesh with a front pinion gear 27, and the front sun gear 25 and the front ring gear 28 are connected via the front pinion gear 27. Has been done. In this way, the front sun gear 25, the front ring gear 28, and the front pinion gear 27 constitute the front planetary gear train 29.

Further, the input shaft 11 has a clutch drum 3
0 is fixed, and a high speed clutch hub 31 connected to the front carrier 26 and a reverse clutch hub 32 connected to the front sun gear 25 are rotatably mounted on the input shaft 11 radially inward of the clutch drum 30. Has been done.
A plurality of friction plates 33 and 34 are mounted between the clutch drum 30 and the high speed clutch hub 31 and the reverse clutch hub 32, respectively.
And a reverse clutch 36. By pressing the friction plates 33 and 34 in the axial direction, the clutch drum 30 and the high speed clutch hub 31 or the reverse clutch hub 32 are connected, and the front carrier 26 or the front sun gear 25 rotates integrally with the input shaft 11.

A first brake hub 37 is fixed to the reverse clutch hub 32, and a plurality of friction plates 39 are mounted between the first brake hub 37 and the transmission case 16 to form a first brake 40. Has been done. When the friction plate 39 is pressed, the first brake hub 37 is fixed to the transmission case 16, so that the rotation of the front sun gear 25 is stopped.

A low speed clutch drum 41 is fixed to the front carrier 26, and a low speed clutch hub 42 is fixed to the outer peripheral surface of the rear ring gear 23. A plurality of friction plates 43 are mounted between the low speed clutch drum 41 and the low speed clutch hub 42, and the low speed clutch 44
Is configured. When the friction plate 43 is pressed, the rear ring gear 23 and the front carrier 26 are connected and rotate integrally.

A second brake hub 46, which is connected to the transmission case 16 via a one-way clutch 45, is fixed to the end of the low speed clutch drum 41, and between the second brake hub 46 and the transmission case 16. A plurality of friction plates 48 are attached to the second
The brake 49 is configured. This friction plate 48
When is pressed, the second brake hub 46 is fixed to the transmission case 16, so that the front carrier 2
6 is fixed, and the revolution movement of the front pinion gear 27 is stopped. In addition, the second brake hub 46 is connected to the transmission case 16 via the one-way clutch 45.
When the pressing operation of the friction plate 48 is released, the revolution movement of the front pinion gear 27 can be performed only in one direction.

The front ring gear 28 and the rear carrier 21 of the two planetary gear trains 24 and 29 are connected to each other, the output shaft 13 is connected to the rear carrier 21, and a plurality of clutches 35 and 36 which are friction engagement devices. , 44 and the plurality of brakes 40, 49 are controlled to be engaged and disengaged so that the rotation of the input shaft 11 causes two planetary gear trains 24, 2
It is transmitted to the output shaft 13 via 9.

A center differential device 12 is mounted between the output shaft 13 and a rear wheel output shaft 15 provided on the concentric shaft of the output shaft 13. The center differential device 12 is of a compound planetary gear type, and has a first sun gear 50 fixed to one end of the output shaft 13 and a second sun gear 51 fixed to the rear wheel output shaft 15. The first sun gear 50 and the second sun gear 51 have a first outer side in the radial direction.
A plurality of integrated pinion gears 52 that mesh with the sun gear 50 and the second sun gear 51 are arranged.
It is rotatably supported by. A front wheel drive gear 58 is integrally provided at an end of the carrier 53, and a front wheel driven gear 59 provided at one end of the front wheel output shaft 14 meshes with the front wheel drive gear 58 to transmit power to the front wheels.

With this structure, the output of the automatic transmission is the first sun gear 5 of the center differential device 12.
When 0 is input, power is distributed and transmitted to the second sun gear 51 and the carrier 53 supporting the integrated pinion gear 52 via the integrated pinion gear 52, and both front wheels and rear wheels can be driven. . At this time, the rotation of the integrated pinion gear 52 differentially absorbs the rotation difference between the front and rear wheels.

A differential limiting clutch hub 54 is fixed to the rear wheel output shaft 15, and a differential limiting clutch drum 55 is fixed to an end of the carrier 53. A plurality of friction plates 56 are mounted between the differential limiting clutch hub 54 and the differential limiting clutch drum 55 to form a differential limiting clutch 57. As a result, when the front wheels or the rear wheels slip and large differential rotation occurs, the differential limiting clutch 57 is engaged and differential rotation is suppressed.

Friction engagement devices 35, 36, 40, 44, 4 which are engaged when the power transmission path of such an automatic transmission is selected and the first-fourth speeds and the reverse speed change are performed.
9, 57 will be described. When the gear ratio of the first speed is selected and the vehicle travels, the low speed clutch 44 is engaged and the rotation of the input shaft 11 is decelerated via the rear planetary gear train 24. At this time, since the rear ring gear 23 is connected to the transmission case 16 via the one-way clutch 45, the rear ring gear 23 is fixed during acceleration, and the rear pinion gear 22 revolves around the rear sun gear 20 to rotate on the output shaft 13. introduce.

When the second speed is selected, the low speed clutch 44 and the first brake 40 are engaged. Since the front sun gear 25 is fixed and the front carrier 26 and the rear ring gear 23 are connected, the rotation speed of the rear ring gear 23 is increased compared to the first speed.

When the third speed is selected, the low speed clutch 44 and the high speed clutch 35 are engaged. Input shaft 11
Since the rear ring gear 23 and the rear ring gear 23 are connected via the high speed clutch 35 and the low speed clutch 44, the input shaft 11
Is transmitted to the output shaft 13 as it is.

When the fourth speed is selected, the high speed clutch 35 and the first brake 40 are engaged. Since the front sun gear 25 is fixed and the front carrier 26 and the input shaft 11 are connected, the speed is increased by the rotation of the front ring gear 28 as compared with the third speed.

When reverse is selected, the reverse clutch 36 and the second brake 49 are engaged. Since the input shaft 11 and the front sun gear 25 are connected and the revolution movement of the front pinion gear 27 is stopped, the rotation of the input shaft 11 is reversed by the front ring gear 28 and transmitted to the output shaft 13.

In such an automatic transmission, by engaging a plurality of clutches 35, 36, 44 and brakes 40, 49, which are friction engagement devices, the rotation of the input shaft 11 is converted to the center differential. The differential limiting clutch 57, which is a frictional engagement device that is transmitted to the device 12 and travels in four-wheel drive, is engaged and controlled to improve traveling performance in four-wheel drive. Therefore, the engagement control of the friction engagement device is always performed according to the traveling situation.

FIG. 2 is a sectional view taken along the axial direction showing a part of the friction engagement device according to one embodiment of the present invention, and FIG. 3 shows one example of the friction engagement device along AA of FIG. It is sectional drawing which shows a part. 4 is a sectional view showing a part of the friction engagement device taken along the line BB of FIG. 2, and FIG. 5 is a sectional view showing a part of the friction engagement device taken along the line C-C of FIG. is there. The friction engagement device shown in FIGS. 2 to 5 presses the friction plate,
The first brake hub 37 that is rotationally driven is the first brake 40 that is fastened to the transmission case 16 and stopped.

A plurality of inner engagement grooves 65 are formed on the outer peripheral surface of the small-diameter cylinder, that is, the first brake hub 37 in the axial direction, and the large-diameter cylinder, that is, the first brake hub 37.
Transmission case 1 installed radially outward of
6, a plurality of outer engagement grooves 66 are formed on the inner peripheral surface in the axial direction.
Are formed.

The large-diameter friction plate 67 fitted in the outer engagement groove 66 has a friction surface 67a in the form of a thin annular ring. The outer engagement groove 66 is formed on the outer peripheral portion of the friction surface 67a.
A plurality of outer engagement portions 67b corresponding to
The large-diameter friction plate 67 is supported by the transmission case 16 by engaging the outer engagement portion 67b with the outer engagement groove 66. Further, as shown in FIG. 3, the width of the outer engagement groove 66 is formed wider than the width of the outer engagement portion 67b, so that the large-diameter friction plate 67 can slide in the axial direction. 68 is provided.

The small-diameter friction plate 69 mounted in the inner engagement groove 65 has a friction surface 69a in the form of a thin annular ring. As shown in FIG. 3, the inner surface of the friction surface 69a has a plurality of inner engagement portions 69b corresponding to the inner engagement grooves 65.
Is formed, and the inner engagement groove 69 b is formed in the inner engagement groove 65.
Is engaged, the small-diameter friction plate 69 is supported by the first brake hub 37. Also, as shown in FIG.
The width of the inner engagement groove 65 is formed wider than the width of the inner engagement portion 69b, and a sliding gap 70 is provided so that the small diameter friction plate 69 can slide in the axial direction.

A plurality of large-diameter friction plates 67 and small-diameter friction plates 69 are mounted alternately in the axial direction,
A stopper plate 71 that restricts movement in the axial direction and a pressing plate 7 that transmits a pressing load to the friction plates 67 and 69 are provided at both ends of the friction plates 67 and 69 that are mounted.
2 and are installed. Therefore, the pressing plate 72
Is pressed toward the stopper plate 71, the friction plates 67 and 69 are pressed against each other and the transmission case 16 is pressed.
Can be fastened to the first brake hub 37.

As shown in FIGS. 2, 4 and 5, an annular cylinder 73 having a sliding contact surface 73a therein is mounted on the inner surface of the transmission case 16.
An engagement portion 73b is formed on the outer peripheral surface of the cylinder 73 so as to correspond to the outer engagement groove 66, and the cylinder 73 is fixed to the transmission case 16. The circular piston 74 is brought into contact with the sliding contact surface 73a of the cylinder 73.
The piston 74 can be slid forward by supplying the hydraulic pressure to the hydraulic chamber 75 formed between the piston 74 and the cylinder 73. Also, the piston 7
A protrusion-shaped stop portion 74a is formed on the outer side in the radial direction of 4, and the rotation of the piston 74 is stopped by engaging the stop portion 74a with the outer engagement groove 66. Further, the end face of the piston 74 is provided with a plurality of pressing portions 7 in the axial direction.
5 and a spring holding portion 76 are formed, the pushing portion 75 transmits the pushing load accompanying the forward sliding of the piston 74 to the pushing plate 72, and the projecting spring holding portion 76 slides the piston 74 backward. A spring member that allows the return spring 77 to be held in the axial direction.

An annular retainer 78 is in contact with the other ends of the plurality of return springs 77, one end of which is attached to the spring holding part 76. In this way, the return spring 77 is held at both ends by the spring holding portion 76 and the retainer 78. A ring groove 79 is formed on the inner surface of the transmission case 16 in the circumferential direction, and a circular snap ring 80 made of a spring material and having a cutout is attached to the ring groove 79. It is held in the transmission case 16 by a spring force that expands in the radial direction. An end surface of the retainer 78 inscribed in the transmission case 16 contacts an end surface of the snap ring 80 protruding from the ring groove 79,
The movement of the retainer 78 is restricted in the axial direction.

The fastening operation of such a friction engagement device will be described. The state before engagement is a state in which the first brake hub 37 is rotationally driven and the piston 74 is arranged in the retracted position in which the return spring 77 does not press. First, when hydraulic pressure is supplied to the hydraulic chamber 75,
The piston 74 slides forward and starts transmitting the pressing load to the pressing plate 72 via the pressing portion 75. At this time, the return spring 77 mounted parallel to the pressing portion 75 is
Since the movement of one end is regulated by the snap ring 80 and the other end is pressed by the piston 74, the piston 74
Is compressed by the amount of sliding.

On the other hand, the pressing load from the piston 74 is transmitted to the friction plates 67 and 69 via the pressing plate 72, and the stopper plate 71 regulates the sliding in the axial direction. The friction plate 67 and the small diameter friction plate 69 are pressed against each other. At this time, the small-diameter friction plate 69 attached to the first brake hub 37 is
The large-diameter friction plate 67 is connected to the outer engaging groove 66 and the outer engaging portion 6.
Only the sliding gap 68 provided between the transmission case 16 and 7b is rotated relative to the transmission case 16.
The rotational force generated by the large-diameter friction plate 67 performing the offset rotation is transmitted to the piston 74 via the pressing plate 72 and the pressing portion 75. Since the stopping portion 74 a that engages with the piston 66 is provided, the rotational force transmitted is the piston 74.
Is cut off by.

When the friction plates 67 and 69 are pressed against each other by the pressing load of the piston 74, the first brake hub 37 and the transmission case 16 are connected and the rotation of the first brake hub 37 is stopped. And the hydraulic chamber 75
When the hydraulic pressure is released, the piston 74 moves backward due to the compressed spring force of the return spring 77, and the pressure contact between the friction plates 67 and 69 is released.
The first brake hub 37 can rotate freely.

As described above, the rotational force interrupted by the piston 74 is not transmitted to the snap ring 80 via the return spring 77 and the retainer 78. For example, the snap ring 80 has burrs or the like. Also, it is possible to prevent the snap ring 80 from falling off without compressing the snap ring 80 by the rotational force.

FIG. 6 is a sectional view taken along the axial direction showing a part of a friction engagement device according to another embodiment of the present invention, and FIG. 7 is a part of the friction engagement device taken along line D-D of FIG. FIG. The friction plates 67, 69 shown in FIG.
Brake hub 37 and transmission case 1
6 is the same as the configuration shown in FIG.

As shown in FIGS. 6 and 7, the sliding contact surface 73
An annular cylinder 73 having a on the inner surface and a fixing hole 73c on the end surface is mounted on the inner wall surface of the transmission case 16. An engagement portion 73b is formed on the outer peripheral surface of the cylinder 73 so as to correspond to the outer engagement groove 66, and the cylinder 73 is fixed to the transmission case 16. An annular piston 74 is mounted in contact with the sliding contact surface 73a of the cylinder 73, and the piston 74 is slid forward by supplying hydraulic pressure to a hydraulic chamber 75 formed between the piston 74 and the cylinder 73. be able to. Also,
A guide hole 74b is formed at the end of the piston 74, a rod-shaped guide pin 81 is fixed in the fixing hole 73c of the cylinder 73 in the axial direction, and the guide pin 81 slides in the guide hole 74b in the axial direction. By being movably fitted, the rotation of the piston 74 is stopped. The spring holder 7
6, pressing portion 75, return spring 77, retainer 7
8 and the snap ring 80 have the same configuration as that shown in FIGS.

When the friction engagement device is engaged, the rotational force transmitted to the piston 74 via the pressing plate 72, that is, the rotational force generated by the large-diameter friction plate 67 rotating by the sliding gap 68. Is a guide pin 8 that is fixed by being connected to the transmission case 16.
1, the piston 74 shuts off. Therefore, the rotational force interrupted by the piston 74 is not transmitted to the snap ring 80 via the return spring 77 and the retainer 78, and it is possible to prevent a malfunction due to the rotation of the snap ring 80.

FIG. 8 is a sectional view taken along the axial direction showing a part of a friction engagement device according to another embodiment of the present invention, and FIG. 9 is an example of the friction engagement device taken along line EE of FIG. It is sectional drawing which shows a part. The friction plates 67, 69 shown in FIG.
The first brake hub 37 and the transmission case 16 have the same configuration as shown in FIG.

As shown in FIGS. 8 and 9, the sliding contact surface 73
The cylinder 73 having a on its inner surface is mounted on the inner surface of the transmission case 16. An engagement portion 73b is formed on the outer peripheral surface of the cylinder 73 so as to correspond to the outer engagement groove 66, and the cylinder 73 is fixed to the transmission case 16. Sliding contact surface 73a of the cylinder 73
An annular piston 74 is mounted in contact with, and the piston 74 can be slid forward by supplying hydraulic pressure to a hydraulic chamber 75 formed between the piston 74 and the cylinder 73. The spring holding portion 76, the pressing portion 75, the return spring 77, the retainer 78, and the snap ring 80 have the same configurations as those shown in FIGS.

Between the retainer 78 and the snap ring 80, a fixed ring 82 having an annular contact surface 82a and an engaging portion 82b on the outer peripheral portion of the contact surface 82a is mounted. The engaging portion 82b of the fixing ring 82 and the outer engaging groove 66
By engaging with and, the fixed ring 82 is held by the transmission case 16, and the rotation of the fixed ring 82 is stopped. In this way, the retainer 78 is restricted from moving in the axial direction by the snap ring 80 via the contact surface 82a of the fixed ring 82 that does not rotate.

When the friction engagement device is engaged, the rotational force transmitted to the piston 74 via the pressing plate 72, that is, the rotational force generated by the large-diameter friction plate 67 being displaced by the sliding gap 68 and rotating, is , The fixed ring 8 which is transmitted to the retainer 78 via the return spring 77 but whose rotation is restricted by the transmission case 16.
Since the retainer 78 and the snap ring 80 are in contact with each other via 2, the rotational force of the retainer 78 is blocked by the fixed ring 82 and is not transmitted to the snap ring 80. Therefore, the rotational force interrupted by the fixed ring 82 is not transmitted to the snap ring 80 that is in contact with the fixed ring 82, and it is possible to prevent a malfunction due to the rotation of the snap ring 80.

As described above, the friction engagement device of the present invention has the sliding gap 68, so that the rotational force generated from the friction plate 67 at the time of fastening can be applied to the snap ring 8.
It is configured not to transmit to 0. Between the friction plate 67 and the snap ring 80, a stopping portion 74a that restrains the rotation of the piston 74, a guide pin 81, or a fixed ring 82 that does not rotate is mounted. The stopping portion 74a and the guide pin The rotation force can be interrupted at 81, or at the attachment site of the fixing ring 82,
A frictional engagement device in which the rotational force is not transmitted to the snap ring 80 can be used.

Further, since the rotational force is not transmitted to the snap ring 80, the low tension snap ring 80 can be adopted, and the cost can be reduced by changing the material and the size. The cost can be reduced by reducing the deburring process performed in the process of processing the snap ring 80. Further, the snap ring 80 does not scrape the transmission case 16 to generate metal powder, and the performance of the transmission can be stabilized. In addition, since the piston 74 is not rotated with respect to the cylinder 73 in the restraint portion 74a and the guide pin 81, the durability of the seal member provided on the sliding contact surface 73a can be improved.

It is needless to say that the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the scope of the invention. For example, although the friction engagement device shown in the embodiment of the present invention is used in an automatic transmission, it can also be used in a continuously variable transmission and is not limited to these. Not only the brake but also the clutch can be used. Further, a plurality of the restraining portions 74a and the guide pins 81 may be provided depending on the magnitude of the rotational force generated. Further, the large-diameter friction plate 67, the snap ring 80, the stopping portion 74a, the guide pin 81, the fixing ring 8
2 is a transmission case 16 which is one member
However, the movement is not limited to the same member, and even if it is a different member, it can be applied as long as the relative rotation speed does not occur between the members. It is needless to say that the retainer 78 can be used by forming a restraint portion on the outer peripheral portion thereof and providing the retainer 78 with the function of a fixing ring.

[0055]

According to the present invention, the piston is provided with the stopper portion, and the stopper portion is engaged with the engagement groove of the large-diameter cylindrical body.
Since the rotational force generated from the friction plate is not transmitted to the snap ring and there is no need to add a rotation prevention function to the snap ring, a friction engagement device that prevents the snap ring from rotating at a low cost is provided. Can be provided.

According to the present invention, the guide pin is provided in the cylinder fixed to the large-diameter cylindrical body, and the guide pin is slidably fitted in the guide hole of the piston, so that the rotational force generated from the friction plate is generated. Since it is not transmitted to the snap ring and it is not necessary to add a rotation preventing function to the snap ring, it is possible to provide a friction engagement device in which the snap ring does not rotate at low cost.

According to the present invention, by providing the fixing ring fixed to the large-diameter cylindrical body between the snap ring and the spring member, the rotational force generated from the friction plate is not transmitted to the snap ring. In addition, since it is not necessary to add a rotation preventing function to the snap ring, it is possible to provide a friction engagement device in which the snap ring does not rotate at low cost.

[Brief description of drawings]

FIG. 1 is a skeleton diagram showing an automatic transmission having a plurality of friction engagement devices according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the axial direction showing a part of the friction engagement device according to the embodiment of the present invention.

3 is a cross-sectional view showing a part of the friction engagement device taken along the line AA of FIG.

4 is a cross-sectional view showing a part of the friction engagement device taken along the line BB of FIG.

5 is a cross-sectional view showing a part of the friction engagement device taken along the line CC of FIG.

FIG. 6 is a sectional view taken along the axial direction showing a part of a friction engagement device according to another embodiment of the present invention.

7 is a cross-sectional view showing a part of the friction engagement device taken along the line DD of FIG.

FIG. 8 is a sectional view taken along the axial direction showing a part of a friction engagement device according to another embodiment of the present invention.

9 is a cross-sectional view showing a part of the friction engagement device taken along line EE of FIG.

[Explanation of symbols]

16 Transmission case (large diameter cylinder) 30 clutch drum (large diameter cylinder) 31 High-speed clutch hub (small diameter cylinder) 32 Reverse clutch hub (small diameter cylinder) 33 Friction plate 34 Friction plate 37 1st brake hub (small diameter cylinder) 39 Friction plate 41 Low speed clutch drum (large diameter cylinder) 42 Low speed clutch hub (small diameter cylinder) 43 Friction plate 46 Second brake hub (small diameter cylinder) 48 friction plate 54 Limited differential clutch hub (small diameter cylinder) 55 Differential limited clutch drum (large diameter cylinder) 56 Friction plate 65 Inner engagement groove (engagement groove) 66 Outer engagement groove (engagement groove) 67 Large diameter friction plate (friction plate) 69 Small diameter friction plate (friction plate) 73 cylinders 74 piston 74a Block 74b Guide hole 77 Return spring (spring member) 80 snap ring 81 guide pin 82 fixing ring

Claims (3)

[Claims] 1. A large-diameter cylindrical body having an engagement groove formed on its inner peripheral surface for engaging a plurality of friction plates, and a plurality of friction plates arranged inside the large-diameter cylindrical body so as to be rotatable relative to each other. A friction engagement device having a small-diameter cylindrical body having an engaging groove to be engaged with the outer peripheral surface, the piston being incorporated in a cylinder mounted to the large-diameter cylindrical body and applying a pressing force to the friction plate. A spring member which is formed between a portion of the snap ring engaged with the large-diameter cylindrical body and has a notch portion and the piston, and which applies a spring force in a direction to return the piston; And a stop portion that engages with the engagement groove of the large-diameter cylindrical body. 2. A large-diameter cylindrical body having engagement grooves formed on the inner peripheral surface for engaging a plurality of friction plates, and a plurality of friction plates arranged inside the large-diameter cylindrical body so as to be rotatable relative to each other. A friction engagement device having a small-diameter cylindrical body having an engaging groove to be engaged with the outer peripheral surface, the piston being incorporated in a cylinder mounted to the large-diameter cylindrical body and applying a pressing force to the friction plate. A spring member that is formed between a portion of the snap ring engaged with the large-diameter cylindrical body and has a notch portion and the piston, and that applies a spring force in a direction to return the piston; And a guide pin that is fitted in a guide hole formed in the piston so as to be slidable in the axial direction. 3. A large-diameter cylindrical body having an engagement groove formed on the inner peripheral surface for engaging a plurality of friction plates, and a relatively rotatably arranged inside the large-diameter cylindrical body. A friction engagement device having a small-diameter cylindrical body having an engaging groove to be engaged with the outer peripheral surface, the piston being incorporated in a cylinder mounted to the large-diameter cylindrical body and applying a pressing force to the friction plate. A spring member, which is formed between a portion of the snap ring engaged with the large-diameter tubular body and has a notch portion, and which applies a spring force in a direction in which the piston is returned; Disposed between a ring and the spring member,
A friction engagement device having a fixing ring fixed to the large-diameter cylindrical body.