JPH01172643A - Driving power transmitting device - Google Patents

Abstract

PURPOSE:To provide the lock-up function by engaging the outer plate of a multidisc clutch onto the inner periphery of a housing and engaging the inner plate of the multidisc clutch with a cam engagement body and a rotary shaft. CONSTITUTION:A front wheel side driving shaft 15 is integrally joined at one edge of the rotary housing 21 of a driving power transmission device 20, and a rear wheel side driving shaft 16 is spline-engaged in a rotary shaft 22. A pair of cam engagement bodies 30 for pressing a multidisc clutch 25 is arranged in a lubricating oil chamber 27. The inner plate 38 of the multidisc clutch 25 is engaged with the cam engagement bodies 31 and 33 and the rotary shaft 22. A portion of the revolution torque by the multidisc clutch 25 is directly transmitted to the rotary shaft 22, and the torque which flows in the cam engagement bodies 31 and 33 can be dispersed. Therefore, even if the rigidity of the cam engagement body is not increased, the lock-up function can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a driving force transmission device used in a four-wheel drive vehicle.

<Prior art> A driving force transmission system that includes a multi-disc clutch that is disposed between a front-wheel drive shaft and a rear-wheel drive shaft and transmits torque between the two shafts, and an operating piston that operates the multi-disc clutch. The device is equipped with a differential pump that discharges pressure oil through the relative rotation of the front drive shaft and the rear drive shaft, and the pressure generated by this differential pump is applied to the actuating piston to apply friction to the multi-disc clutch. It is designed to be engaged.

In this type of driving force transmission device, if the multi-disc clutch generates sliding friction for a long period of time, such as when the wheels come off, there is a risk that frictional heat will be generated in the multi-disc clutch and damage the clutch plates.

Conventionally, as a solution to such problems,
As described in Japanese Patent No. 142,945, a driving force transmission device equipped with a lock-up mechanism using a cam is known.

<Problems to be Solved by the Invention> However, in the above-mentioned known driving force transmission device, the entire torque flowing between the front wheel drive shaft and the rear wheel drive shaft acts on the cam portion during lockup. The rigidity of the structure must be increased, which causes the problem that the structure becomes complicated and large.

<Means for Solving the Problems> The present invention has been made in view of the above-mentioned conventional problems, and has a structure in which a housing is connected to one of the front wheel drive shaft and the rear wheel drive shaft, A rotating shaft rotatably supported by the housing is connected to the other, and a pair of cam engaging bodies are disposed within the housing so as to be relatively rotatably cam-engaged in the circumferential direction and press the multi-disc clutch by relative rotation. and connecting one of the pair of cam engaging bodies to the rotating shaft,
the other is relatively rotatably fitted to the rotating shaft, and an outer plate of the multi-disc clutch is engaged with the inner periphery of the housing;
The inner plate of the multi-disc clutch disposed between each of these outer plates is engaged with the other cam engaging body and the rotating shaft. When the relative rotational speed difference between the rear wheel drive shafts increases, the friction engagement force of the multi-disc clutch increases, and the transmitted torque exceeds the bias set by the disc spring, the pair of clutch engagement bodies rotate relative to each other. Relative displacement in the axial direction due to cam action. The outer plate and the inner plate are pressed by the relative axial displacement of the pair of clutch engaging bodies, and the outer plate and the inner plate are almost directly connected. As a result, the torque transmitted by the multi-disc clutch increases rapidly, making it easier to escape from mud etc., and suppressing the sliding friction between the outer plate and the inner plate to prevent damage to both plates. In this case, part of the rotational torque transmitted to the inner plate of the multi-plate clutch is directly transmitted to the rotating shaft, and the rest is transmitted to the rotating shaft via the clutch hub and cam plate.

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 3, 10 is an engine, 11 is a transmission, 13 is a front wheel differential, 14 is a rear differential, 15 is a front wheel drive shaft, 16 is a rear wheel drive shaft, 17 is a front wheel, and 18 is a rear wheel drive shaft. 20 indicates a rear wheel, and 20 indicates a driving force transmission device provided between the front wheel drive shaft 15 and the rear wheel drive shaft 16. The output of the engine 10 is transmitted to the front wheel differential device 13 via the transmission 11, and drives the front wheels 17.
The rotation is transmitted to the front wheel drive shaft 15, and its rotation is transmitted to the rear wheel drive shaft 16 via the drive force transmission device 20, and the rotation is transmitted to the rear wheel drive shaft 16 through the drive force transmission device 20.
to drive.

As shown in FIG. 1, the driving force transmission device 20 includes a rotary housing 21, a rotary shaft 22 that extends vertically through the rotary housing 21 and is rotatably supported, and a rotary housing 21 and a rotary shaft 22. A hydraulic pressure generating means 23 that generates hydraulic pressure according to the differential rotation of the hydraulic pressure generating means 23 and an operating piston 24 to which the hydraulic pressure generated by the hydraulic pressure generating means 23 is applied are frictionally engaged by the pressing force of the operating piston 24. It is mainly composed of a multi-disc clutch 25.

The front wheel drive shaft 1 is disposed at one end of the rotating housing 21.
5 are integrally connected to each other, and the rear wheel drive shaft 16 is spline-engaged within the rotary shaft 22. A lubricating oil chamber 27 is formed in the rotating housing 21 concentrically with the rotating shaft 22 , and one end opening of the lubricating oil chamber 27 is closed by an end cover 28 . Inside the lubricating oil chamber 27, a clutch hub 31 constituting one of the pair of cam engaging bodies 30 is rotatably and axially movably supported on the outer periphery of the rotating shaft 22. Balls 32 are held at equal angular intervals on the circumference. A torque receiving body 31A is provided at one end of the clutch hub 31 so as to sandwich the multi-disc clutch 25 between it and the operating piston 24. Further, a cam plate 33 constituting the other of the pair of cam engaging bodies 30 is spline-engaged with the outer periphery of the rotating shaft 22 . On the surface of the cam plate 33 facing the end surface of the clutch hub 31, the same number of cam grooves 34 that engage with the engagement balls 32 are formed at equal angular intervals on the circumference, and the cam grooves 34 are arranged along the two-dot chain line. As shown, it has a 7-shaped shape along the circumferential direction. Each of the engaging balls 32 is normally engaged with the center of the V-shaped cam groove 34 by the optical force of a disc spring 35 inserted between the cam plate 33 and the clutch hub 31.

Further, a multi-disc clutch 25 is provided in the lubricating oil chamber 27.
A plurality of outer plates 37 and inner plates 38 constituting the clutch hub 31 are arranged alternately, and the outer plate 37 is spline engaged with the inner periphery of the rotating housing 21, and a portion 38A of the inner plate 38 is connected to the outer periphery of the clutch hub 31. In addition, the remaining portions 38B are spline engaged with the outer periphery of the rotating shaft 22, respectively.

A cylindrical space 40 limited in the axial direction is formed between the working piston 24 and the inner end of the rotary housing 21, and a rotor having a wall thickness slightly smaller than the axial dimension of the space 40 is formed in the space 40. 41 is housed in a slidable manner. As shown in FIG. 2, the rotor 41 has a center portion splined to the outer periphery of the rotating shaft 22, and has two blades 42 extending in the diametrical direction. As a result, the space 40 is divided into a plurality of spaces on the circumference by a plurality of blades 42, and each of these spaces is filled with a high viscosity oil 44 such as silicone oil.

The oil pressure generating means 23 is constituted by the rotor 41 having the blades 42 housed in the cylindrical space 40 and the high viscosity oil 44.

In the above configuration, when the front wheel drive shaft 15 and the rear wheel drive shaft 16 rotate relative to each other and the rotor 41 rotates relatively within the rotation housing 21, the high viscosity oil 44 filled in the space 40 is transferred to the blade 42. As a result, the fluid is forced to move between two closely spaced surfaces at a flow rate that corresponds to the rotational speed difference. At this time, an internal pressure proportional to the rotational speed of the rotor 41 is generated in the space 40 due to viscous friction between the rotating housing 21 and both end surfaces of the operating piston 24 . That is, for example, when the blade 42 rotates in the direction of the arrow with respect to the rotary housing 21, this internal pressure has the highest pressure distribution at two adjacent blocks and the lowest at point B, and the rotation of the blade 42 is caused in the space 40. A pressure proportional to the speed is generated, and this pressure acts on the actuating piston 24 and presses the multi-disc clutch 25.

Therefore, a plurality of outer plates 37 and inner plates 38
are frictionally engaged by a pressing force corresponding to the hydraulic pressure acting on the actuating piston 24, and rotational torque is transmitted from the front wheel drive shaft 15 to the rear wheel drive shaft 16 via the multi-disc clutch 25.
It becomes a wheel drive state.

In this case, the inner plate of the multi-plate clutch 25 is 3° 8
A portion of the rotational torque transmitted to the rotary shaft 22 is directly transmitted to the rotary shaft 22, and the rest is transmitted to the rotary shaft 22 via the clutch hub 31, the engagement ball 32, and the cam plate 33.

As a result, even if the front wheels 17 or the rear wheels 18 get stuck in mud or the like and spin, it is possible to escape from the mud or the like.

However, if the escape does not go as planned and you press the accelerator to increase the engine speed, the differential rotation (relative rotational speed difference) between the front drive shaft 15 and the rear drive shaft 16 may occur. ) increases, the frictional engagement force of the multi-disc clutch 25 increases, and the transmitted torque also increases. As a result, the differential rotation reaches Nl (Fig. 4), and the transmitted torque is transmitted to the disc spring 35.
If the bias exceeds the bias set in , the clutch hub 3
1 and the clutch plate 33 rotate relative to each other against the disk spring 35, and the locking ball 32 rides on the cam groove 34. As a result, the outer latch hub 31 is displaced in the axial direction with respect to the clutch plate 33, and receives the torque. The multi-disc clutch 25 is pressed toward the actuating piston 24 by the body 31A. Due to this axial displacement of the clutch hub 31, the outer plate 3
7 and the inner plate 38 are almost directly connected.

As a result, the torque transmitted by the multi-disc clutch 25 is
As shown in the torque transmission characteristic in the figure, the torque increases sharply after a predetermined differential rotation N1, making it easier to escape from the muddy area, etc., and at the same time suppressing the sliding friction between the outer plate 37 and the inner plate 38. This will prevent damage to both plates.

Also in this case, part of the rotational torque transmitted to the inner plate 34 of the multi-disc clutch 25 is transferred to the rotation shaft 2.
Since the torque is directly transmitted to the cam engaging body 2, the torque is not concentrated on the cam engaging body, and there is no need to increase the rigidity of the cam engaging body as much as in the past.

In the above-mentioned embodiment, an example was described in which the hydraulic pressure acting on the actuating piston 24 is generated by forcibly moving high-viscosity oil with a blade, but it may also be generated using a conventionally well-known differential pump. good.

Furthermore, in the embodiment described above, the pair of cam engaging bodies 30
Although an example has been described in which the cams are engaged via the engagement ball 32, based on the same idea, the pair of cam engagement bodies 30 may be engaged with each other at their chevron-shaped cam surfaces.

<Effects of the Invention> As described above, the present invention has a cam engaged in a housing connected to one of a front wheel drive shaft and a rear wheel drive shaft so as to be relatively rotatable in the circumferential direction. A pair of cam engaging bodies that press the plate clutch are arranged, one of the pair of cam engaging bodies is connected to a rotating shaft rotatably supported on the housing, and the other is fitted to the rotating shaft so that it can rotate relative to the housing. The outer plate of the multi-disc clutch is held on the inner periphery, and the inner plate of the multi-disc clutch disposed between these outer plates is engaged with the other cam engaging body and the rotating shaft, respectively. Therefore, part of the rotational torque from the multi-disc clutch is transmitted directly to the rotating shaft, and the torque flowing to the cam engaging body can be dispersed, so the lock-up function can be enjoyed without increasing the rigidity of the cam engaging body, which was conventionally required. effective.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view of a driving force transmission device, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a schematic diagram of a four-wheel drive vehicle. , 4th. The figure is a diagram showing transmission torque characteristics with respect to differential rotation. 15... Front wheel side drive shaft, 16... Rear wheel side drive shaft, 2
1... Rotating housing, 22... Rotating shaft, 23...
- Hydraulic pressure generating means, 24... Working piston, 25...
Multi-plate clutch, 31.33...Cam engaging body, 37...
・Outer plate, 38...Inner plate.

Claims (1)

[Claims] (1) A multi-disc clutch that is disposed between the front-wheel drive shaft and the rear-wheel drive shaft and transmits torque between the two shafts, an actuating piston that presses the multi-disc clutch, and the front-wheel drive shaft. and a hydraulic pressure generating means for applying hydraulic pressure to the actuating piston in accordance with differential rotation with the rear wheel drive shaft, the housing being disposed on one of the front wheel drive shaft and the rear wheel drive shaft. a pair of cams, the other of which is connected to a rotary shaft that is rotatably supported by the housing, the cam engages within the housing so as to be relatively rotatable in the circumferential direction, and presses the multi-disc clutch by relative rotation. an engaging body is arranged, one of the pair of cam engaging bodies is connected to the rotating shaft, the other is fitted to the rotating shaft so as to be relatively rotatable, and an outer plate of the multi-disc clutch is attached to the inner periphery of the housing. A driving force transmission device in which inner plates of a multi-disc clutch disposed between the outer plates are respectively engaged with the other cam engaging body and the rotating shaft.