JP2736786B2 - Wet hydraulic multi-plate clutch for power distribution of four-wheel drive vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a wet-type hydraulic multi-plate clutch for power distribution interposed in a power transmission system of a four-wheel drive vehicle.

[Prior art]

Conventionally, such a wet hydraulic multi-plate clutch has been
The thing described in 61-28531 is known. this is,
A hydraulic piston for pressing a clutch plate is slidably fitted to a clutch drum as a cylinder, and the hydraulic piston rotates together with the clutch drum.

[Problems to be solved by the invention]

For this reason, in the hydraulic chamber formed between the hydraulic piston and the clutch drum, centrifugal hydraulic pressure is generated along with rotation of the power transmission system in addition to control hydraulic pressure. When the centrifugal oil pressure increases, the hydraulic piston is pressed by the clutch plate accordingly, and even if the control oil pressure is released, the torque transmission cannot be completely turned off with the clutch plate engaged, There was an inconvenience in performing delicate hydraulic control, such as the inability to control the control hydraulic pressure. Also, the clutch drum needs to secure the clutch plate pressing force to obtain the required transmission torque capacity due to the engagement of the hydraulic piston, and it is difficult to reduce the diameter of the clutch drum. Power transmission efficiency tends to decrease due to stirring resistance. In view of the above circumstances, the present invention prevents the generation of centrifugal hydraulic pressure, enables fine hydraulic control of a wet-type hydraulic multi-plate clutch, improves the power transmission efficiency by reducing the diameter of the clutch drum, and improves the power transmission efficiency. It is an object of the present invention to provide a wet hydraulic multi-plate clutch for power distribution of a four-wheel drive vehicle that can be realized with a simple configuration.

[Means for Solving the Problems]

In order to achieve the above object, the present invention is integrated with a differential device provided in the middle of a power transmission system of a four-wheel drive vehicle,
A wet-type hydraulic multi-plate clutch for power distribution of a four-wheel drive vehicle that changes a transmission torque between front and rear wheels according to the pressure of hydraulic oil, comprising a hydraulic piston that slides with an immobile member in the differential device as a cylinder, The hydraulic piston presses, via a bearing, a working end opposite to the hydraulic chamber to a retainer plate fitted inside the end of the clutch drum of the wet hydraulic multi-plate clutch, and presses the clutch plate in the clutch drum. In addition, the race of the bearing that abuts on the hydraulic piston is locked to the immovable member to prevent the race from rotating.

[Action]

With the above configuration, the hydraulic piston of the wet hydraulic multi-plate clutch for power distribution slides using the immovable member in the differential as a cylinder. The hydraulic piston presses, via a bearing, a working end opposite to the hydraulic chamber to a retainer plate fitted inside the end of the clutch drum of the wet hydraulic multi-plate clutch, and presses the clutch plate in the clutch drum. I do. Therefore, even if the clutch drum and the clutch plate rotate due to the rotation of the power transmission system, the hydraulic piston does not rotate, and no centrifugal hydraulic pressure is generated in the hydraulic chamber formed between the hydraulic piston and the immovable member. In addition, since the race of the bearing contacting the hydraulic piston is locked to the immovable member of the differential device to prevent the race from rotating, it can be realized with a simple configuration, and no rotational force acts on the hydraulic piston. Can be improved in durability reliability.

【Example】

Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings. FIG. 2 shows a power transmission system of a laterally mounted transaxle type four-wheel drive vehicle to which one embodiment is applied, wherein an engine 1, a clutch 2, and a manual transmission 3 are horizontally disposed in the front part of the vehicle body. Behind these, a front wheel differential 4, a transfer device 5, a propeller shaft 6, a wet hydraulic multi-plate clutch 7 for power distribution, and a rear wheel differential 8 are arranged. The power input from the engine 1 to the manual transmission 3 via the clutch 2 is appropriately shifted there, and is output from the output gear 9 to the final reduction gear.
The power is input to the front-wheel differential 4 through the power transmission 10 to the left and right front wheels. The input gear 11 of the transfer device 5 meshes with the final reduction gear 10, and the input gear 11
The power from the transfer device 5, which is taken out rearward through a pair of deflection bevel gears 12, is input to a wet-type hydraulic multiple disc clutch 7 via a propeller shaft 6. The rear-wheel-side power distributed at a predetermined ratio to the front-wheel side by the wet-type hydraulic multi-plate clutch 7 is input to the rear-wheel-side differential 8 through the final reduction gear 13, from which the rear-wheel power is transmitted. Power is transmitted to the wheels. Here, the wet hydraulic multi-plate clutch 7 includes an electric oil pump 14, a regulator valve 15, a transfer clutch valve 16, a duty solenoid valve 1 as shown in FIG.
7, an appropriate control oil pressure is supplied according to the running state by a dedicated oil pressure control system having a pilot valve 18. In this hydraulic control system, a transfer clutch valve 16 that is duty-controlled in a hydraulic circuit system that is pressure-adjusted to a predetermined hydraulic pressure from an electric oil pump 14 by a regulator valve 15 and that reaches the wet hydraulic multi-plate clutch 7 is interposed. , A duty solenoid valve 17 for discharge control in a pilot pressure circuit system having a pilot valve 18.
Is inserted, this duty solenoid valve
17 is adjusted to a desired duty pressure by a duty signal from the control unit 19, whereby the transfer clutch valve 16 is adjusted to a desired clutch pressure. The relationship between the duty ratio, the duty pressure and the clutch pressure is as shown in FIG. Such a hydraulic control system and a wet hydraulic multi-plate clutch 7
Are compactly assembled in the differential carrier 20 of the rear wheel differential 8 as shown in FIG. That is, the differential carrier 20 is connected to the extension case 23 around the input shaft 22 by protruding forward so as to cover a loose fit portion between the drive pinion 21 of the rear wheel differential 8 and the input shaft 22 on the propeller shaft 6 side. The cylinder unit 24 is integrally formed as a stationary member, and as shown in FIG. 1 (a), a valve unit 25 in which the valves 15, 16, 17, 18 are integrally formed on the lower surface of the cylinder unit 24,
The electric oil pumps 14 are fixed to the side surfaces, respectively, and the wet hydraulic multi-plate clutch 7 is disposed in the cylinder portion 24. In the electric oil pump 14, an inner rotor 14b directly connected to an output shaft of a motor 14a and an outer rotor 14c corresponding to the inner rotor 14b are housed in a housing portion 24a on a side surface of the cylinder portion 24, and these are bolted to the housing portion 24a together with the motor 14a. It is covered by a cover 14d to be fixed. The suction port 14e is connected to an oil strainer (not shown) in an oil pan attached to the lower surface of the cylinder portion 24, and the discharge port 14f is connected to the regulator valve 15.
Is communicated to. Here, the wet hydraulic multi-plate clutch 7 includes a clutch drum 7a.
Is fixedly welded to the flange portion 22a at the rear end of the input shaft 22, and the clutch hub 7b is spline-fitted to the shaft portion 21a of the drive pinion 21 to engage with the end of the input shaft 22 via a thrust washer 26. Has been stopped. A plurality of ring-shaped clutch plates are provided on the inner circumference of the clutch drum 7a.
7c is spline-fitted together with the retainer plates 7d at both ends, while a plurality of ring-shaped clutch discs 7e are alternately arranged with the clutch plates 7c on the outer periphery of the clutch hub 7b and spline-fitted. A multi-plate clutch is constituted by the clutch plate 7c, the retainer plate 7d, and the clutch disk 7e. A piston 7f for applying a pressing force to the retainer plate 7d is slidably fitted in the cylinder portion 24, which is an immovable member, and has a partition wall 24.
b and an inner guide cylinder 24c, a hydraulic chamber 7g communicating with the transfer clutch valve 16 is formed, and a working end opposite to the hydraulic chamber 7g is connected to the retainer plate through a release bearing 27 of an angular contact.
Contact 7d. In the release bearing 27, the outer race 27a that abuts on the piston 7f has the claw 27b and the inner guide cylinder 24c.
The inner race 27c is spline-fitted to the inner periphery of the clutch drum 7a, and the rotation of the outer race 27a prevents the piston 7f from rotating with respect to the cylinder portion 24. On the other hand, the shaft portion 21a of the input shaft 22 and the drive pinion 21
Are formed with oil passages 22b and 21b so as to communicate the outer peripheral side of the clutch drum 7a and the inner peripheral side of the clutch hub 7b. Then, the hydraulic oil in the cylinder portion 24 is scraped up on the outer periphery of the clutch drum 7a and supplied to the oil passage 22b by an oil guide (not shown), and the hydraulic oil is guided to the inner peripheral side of the clutch hub 7b via the oil passage 21b. The clutch plate 7 passes through an oil passage (not shown) provided in
c, to lubricate the multi-plate clutch such as the clutch disk 7e. In addition, in order to prevent this leakage of hydraulic oil,
Oil seals 28 and 29 are mounted on the inner peripheral part of the partition wall 24b of the cylinder part 24 and the inner peripheral part of the front part of the extension case 23, respectively. In the four-wheel drive vehicle having the above-described configuration, the power transmitted from the engine 1 to the manual transmission 3 via the clutch 2 is appropriately shifted there, and one of the power is directly input to the front-wheel-side differential 4 while the other is input. Is input to the rear wheel side differential 8 through the wet hydraulic multi-plate clutch 7 to drive four wheels. In this case, the wet-type hydraulic multi-plate clutch 7 is configured such that the clutch plate 7c and the clutch disc 7e are immersed in an appropriate working oil having a predetermined composition and maintain the necessary frictional characteristics, and the rear wheels are arranged from the front wheel side in accordance with the transmission torque. Power distribution to the side. The distribution ratio is gradually increased from the FF state of the front wheels 100% and the rear wheels 0% by the change of the clutch pressure according to the duty ratio signal from the control unit 19, and the rear wheel side is gradually increased.
It changes within the range up to the state. So the control unit
By inputting various signals such as throttle opening signal, rear wheel rotation signal, front wheel rotation signal, and idle signal to 19 and electronically controlling it, it is possible to optimize the front-rear power distribution according to the running condition of the car and road surface conditions Thus, running stability and drivability can be improved. Here, during the four-wheel drive running, if there is a difference in the effective diameter of the front and rear wheels due to a difference in axle weight distribution between the front wheels and the rear wheels of the vehicle, a sudden acceleration, and a shift in the center of gravity when climbing a hill, a relative difference is generated between the front and rear wheels. Rotation occurs. In such a case, the wet-type hydraulic multi-plate clutch 7 functions as a torque limiter by being controlled to a desired clutch pressure, and causes slippage between the clutch plate 7c on the clutch drum 7a side and the clutch disc 7e on the clutch hub 7b side. The generated internal circulation torque is absorbed by the rotation difference between the front and rear wheels. Therefore, acceleration performance and fuel efficiency during four-wheel drive traveling can be improved, and vibration noise of the driving system can be reduced. Looking at the behavior of the wet hydraulic multi-plate clutch 7 itself, even if the clutch plate 7c and the inner race 27c of the release bearing 27 rotate together with the clutch drum 7a with the rotation of the power transmission system, the outer race 27a of the release bearing 27 Is stopped by the cylinder portion 24, which is a stationary member, so that the piston 7f in contact with the outer race 27a also does not rotate. Therefore, it is not necessary to add a rotation stopping mechanism to the piston itself. The piston 7f is fitted to the cylinder portion 24, which is an immovable member with respect to the conventional rotary drum built-in system, and the centrifugal force is set in a hydraulic chamber 7g formed between the piston 7f and the cylinder member 24. No hydraulic pressure is generated, and no unnecessary pressing force is applied to the clutch plate 7c and the like other than the pressing force by the control hydraulic pressure. Therefore, the hydraulic control of the hydraulic chamber 7g is accurate, and delicate hydraulic control is also possible. When the wet hydraulic multi-plate clutch 7 generates slip,
Since the clutch plate 7c and the clutch disk 7e are immersed in an appropriate hydraulic oil having a predetermined composition, desired friction characteristics can be obtained, and no stick-slip occurs. Therefore, unpleasant vibration and noise do not occur, and desired reliability and durability can be obtained for the friction material. The piston 7f of the wet hydraulic multi-plate clutch 7 is configured to slide using the cylinder portion 24 of the differential carrier 20 as a cylinder. In a conventional clutch drum having a built-in piston, the outer diameter of the piston is equal to the outer diameter of the drum. Although it is decided, the piston is separated from the rotating drum and provided on the cylinder of the immovable member, so that the diameter of the clutch drum 7a can be reduced, and therefore, the stirring resistance of the hydraulic oil is reduced by reducing the diameter of the clutch drum 7a. Power transmission efficiency (fuel efficiency) is improved. Further, the hydraulic control system of the wet-type hydraulic multi-plate clutch 7 has a configuration in which the electric oil pump 14 and the valve unit 25 are attached to the cylinder portion 24 of the differential carrier 20, so that no external piping is required and the hydraulic circuit is short. Because of the compact configuration, not only does there be no leak of pressure oil, but also the operating oil pressure of the wet hydraulic multi-plate clutch 7 has good responsiveness. And since the response of operating hydraulic pressure is good, the power distribution ratio is changed instantaneously, such as when the front wheel or the rear wheel slips,
It is possible to control the behavior of the vehicle. Further, since such a wet hydraulic multiple disc clutch 7 is disposed in the cylinder portion 24 of the differential carrier 20, in order to obtain the same effect, a method of disposing a wet hydraulic multiple disc clutch in a transmission transfer device is required. Therefore, the configuration of the transfer device 5 is simplified, and the degree of freedom in the layout of the power train is obtained. In the above embodiment, the wet hydraulic multi-plate clutch 7 is connected to the differential carrier 20 in the rear wheel differential 8.
However, in an automobile having an independent differential device on the front wheel side in the RR-based power train, a wet hydraulic multiple disc clutch is disposed in a differential carrier in the front wheel differential device. . The present invention can be applied to not only manual transmission vehicles but also automatic transmission vehicles and vehicles with continuously variable transmissions. Further, here, the bearing provided between the piston and the clutch plate of the clutch drum has been described as a release bearing. However, the same effect can be obtained by a thrust bearing system as shown in FIG.
The detent of 7f is secured by the claw 31a (5th
(Refer to Fig. (A)).

【The invention's effect】

As described above, according to the present invention, the hydraulic piston of the power distribution wet hydraulic multi-plate clutch slides with the stationary member in the differential device as the cylinder. The hydraulic piston presses, via a bearing, a working end opposite to the hydraulic chamber to a retainer plate fitted inside the end of the clutch drum of the wet hydraulic multi-plate clutch, and presses the clutch plate in the clutch drum. Therefore, even if the clutch drum and the clutch plate rotate due to the rotation of the power transmission system, the hydraulic piston of the wet-type hydraulic multi-plate clutch does not rotate, and the hydraulic chamber formed between the hydraulic piston and the immovable member does not rotate. Does not generate centrifugal oil pressure. Accordingly, unnecessary pressing force due to generation of centrifugal oil pressure in the hydraulic chamber is not applied to the clutch plate, and the wet hydraulic multi-plate clutch for power distribution is supplied to the hydraulic chamber without being affected by the centrifugal oil pressure. The transmission torque between the front and rear wheels can be accurately distributed according to the hydraulic pressure of the hydraulic oil, and the precision of power distribution control between the front and rear wheels by the wet hydraulic multi-plate clutch can be improved. In addition, the wet hydraulic multi-plate clutch for power distribution can be configured without fitting a hydraulic piston to a clutch drum in which a clutch plate is mounted, so that the diameter of the clutch drum can be easily reduced. The power transmission efficiency can be improved by reducing the oil stirring resistance. Furthermore, since the race of the bearing that abuts on the hydraulic piston is prevented from rotating by simply engaging the stationary member of the differential device, the rotation of the hydraulic piston can be realized with a very simple configuration, and In addition, no rotational force acts on the hydraulic piston at all, which has the effect of improving the durability reliability of the hydraulic piston.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention, FIG. 1 (a) is a sectional view taken along line AA of FIG. 1, and FIG. 2 is a four-wheel drive vehicle to which the embodiment is applied. FIG. 3 is a hydraulic circuit diagram used in one embodiment, FIG. 4 is a characteristic diagram of duty pressure and clutch pressure, and FIG. 5 is a sectional view of a main part of another embodiment. FIG. 5A is a perspective view of the race. 1 ... engine, 2 ... clutch, 3 ... manual transmission,
4 Front wheel differential device 5 Transfer device 6
… Propeller shaft, 7 …… Wet hydraulic multi-plate clutch, 7a
... clutch drum, 7b ... clutch hub, 7c ... clutch plate, 7d ... retainer plate, 7e ... clutch disc, 7f ... piston, 7g ... hydraulic chamber, 8 ... rear wheel differential, 9 ... output gear, 10 ... final reduction gear, 11
... input gear, 12 ... bevel gear, 13 ... final reduction gear,
14 ... Electric oil pump, 14a ... Motor, 14b ... Inner rotor, 14c ... Outer rotor, 14d ... Cover, 14
e: Suction port, 14f: Discharge port, 15: Regulator valve, 16: Transfer clutch valve, 17 ...
... Duty solenoid valve, 18 ... Pilot valve, 19 ... Control unit, 20 ... Differential carrier, 21 ... Drive pinion, 21a ... Shaft, 21b ...
... oil passage, 22 ... input shaft, 22a ... flange, 22b ... oil passage, 23 ... extension case, 24 ... cylinder, 24a ... housing, 24b ... partition wall, 24c ... inside Guide cylinder, 25 Valve unit, 26 Thrust washer, 27 Release bearing, 27a Outer race, 27b Claw, 27c Inner race, 28, 29 Oil seal.

Claims (1)

(57) [Claims] 1. The power of a four-wheel drive vehicle, which is integrally formed with a differential device interposed in the power transmission system of the four-wheel drive vehicle and changes the transmission torque between the front and rear wheels according to the pressure of hydraulic oil. A wet hydraulic multi-plate clutch for distribution, comprising: a hydraulic piston that slides as a cylinder with an immovable member in the differential device, wherein the hydraulic piston has a working end opposite to a hydraulic chamber, By pressing the retainer plate internally fitted to the end of the clutch drum via a bearing to press the clutch plate in the clutch drum, the race of the bearing contacting the hydraulic piston is locked to the immovable member. A wet hydraulic multi-plate clutch for power distribution of a four-wheel drive vehicle, wherein the race is prevented from rotating.