JPS62286837A - Driving device for four-wheel driving vehicle - Google Patents

Abstract

PURPOSE:To reduce the dimension of the driving device by installing a piston for operating a clutch disc onto a selecting clutch arranged concentrically onto a propulsion shaft and allowing the piston to surround the propulsion shaft by forming a hydraulic chamber between a shaft supporting body. CONSTITUTION:The selecting clutch 8 of a power transmission cut-off device 1 accommodated into a casing 9 is equipped with a clutch inner 35 and clutch plates 37 and 38 spline-connected with a clutch outer 18 and an operating piston 39 for controlling the operation of the clutch plates 37 and 38, and arranged concentrically with the front half shaft 6a of a propulsion shaft. The operating piston 39 is formed into hollow form surrounding the front half shaft 6a, and a hydraulic pressure chamber 49 is formed between the casing 9, and a hydraulic pressure feeding source 56 is connected. Since the selecting clutch 8 is arranged concentrically with the propulsion shaft, the device can be made compact in a driving system, and also a hydraulic pressure passage can be made simple.

Description

Detailed description of the invention 3. Detailed description of the invention A drive system for a four-wheel drive vehicle, in which a switching clutch capable of switching between transmission and cutoff of power is interposed between either the front or rear wheel, which can be rigidly connected to one wheel, and the power unit. Regarding.

(2) Prior Art Conventionally, such a drive device has been used, for example, in U.S. Pat.
It is known from the publication No. 731.

(3) Problems to be solved by the invention By the way, such a drive device can prevent the rear wheels from locking when the front wheels lock in a state where the front wheels and the rear wheels are rigidly connected. However, in the conventional system described above, the switching clutch is placed in a disengaged state in response to brake operation.

However, this does not provide the advantage of four-wheel drive vehicles, which is the shortened braking distance.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a drive device for a four-wheel drive vehicle that is compact and capable of fully utilizing the above-mentioned advantages of a four-wheel drive vehicle. do.

B0 Structure of the Invention (Means for Solving 11 Problems) According to the present invention, the switching clutch is spline-coupled by alternately stacking the clutch inner and the clutch outer, which are respectively coupled to either the input or output member. A propulsion shaft that connects a power unit and the other wheel, and includes a plurality of clutch devices, a clutch spring that biases each clutch plate in a direction of frictional engagement, and an actuating piston that controls the operation of the clutch plates. The actuating piston is disposed concentrically above, and the actuating piston defines a hydraulic chamber between it and a fixed support that rotatably supports the propulsion shaft, and is slidably engaged with the support, and also concentrically surrounds the propulsion shaft. The hydraulic chamber is formed in a hollow shape, and a hydraulic pressure supply source is connected to the hydraulic chamber for supplying hydraulic pressure to press the actuating piston toward the power cutoff side at an appropriate time.

(2) Since the operation switching clutch is a multi-disc clutch and is arranged concentrically on the propulsion shaft, it is possible to make the switching clutch small in the drive system, and the operation piston is connected to a fixed support. Since a hydraulic chamber is defined between the two and slidably connected to the support, the seal structure is simple and the hydraulic path is simple.

Furthermore, if the front wheels are about to lock, for example, the switching clutch is disengaged, thereby preventing the rear wheels from locking.

(3) Examples Examples of the present invention will be explained below with reference to the drawings.
First, in FIGS. 1 and 2 showing an embodiment of the present invention, each pair of front wheels wr, wr and rear wheels Wr, Wr are suspended on a vehicle body B via a suspension device (not shown), and the front part of the vehicle body B is is equipped with a power unit P consisting of an engine E, a transmission M, a front differential Dr and a transfer T.

A pair of front axles A connected to the left and right front wheels wr and wr, respectively
f, At are interconnected via a front differential Dr. Further, a pair of rear axles Ar, Ar connected to left and right rear wheels Wr, Wr, respectively, are connected to each other via a rear differential device Dr. Further, the output shaft 2 of the transfer T and the input shaft 3 of the rear differential 4ji are connected to each other by a propulsion shaft S having a power transmission/blocking device 1 interposed therebetween.

The propulsion shaft S has a joint J to the output shaft 2 of the transfer T.
1, and a second shaft 5, which is connected to the input shaft 3 of the rear differential device D' through a joint J2.
and a joint J between these first and second axes 4.5
3. and an intermediate shaft 6 connected via J4. Moreover, the intermediate shaft 6 is connected to the first half shaft 6a on the first shaft 4 side and the second half shaft 6a on the first shaft 4 side.
It is divided into a rear half shaft 6b on the shaft 5 side, and a power transmission/blocking device 1 is provided to connect these two-handed shafts 6a, 6b.

In FIG. 3, the power transmission and disconnection device 1 is comprised of a differential limiting clutch 7 and a switching clutch 8, and is housed in a casing 9 serving as a support. The first half shaft 6a is rotatably supported by the casing 9 via a bearing 10 and a seal member 11, and the second half shaft 6b is rotatably supported by the casing 9 via a bearing 12 and a seal member 13. Furthermore, both halves 6a and 6b have the same axis and are disposed oppositely within the casing 9.

The differential limiting clutch 7 has an annular shape defined by a rear shaft 6b as a clutch inner and a clutch outer 18 rotatably supported by the rear shaft 6b via bearings 14, 15 and seal members 16, 17. In a sealed oil chamber 19, a plurality of outer clutch plates 20 spline-coupled to the clutch outer 18 and a plurality of inner clutch plates 21 spline-coupled to the rear half shaft 6b are arranged in an overlapping manner with each other.

The clutch outer 18 is formed by closing both ends of a cylindrical body 22 concentrically surrounding the rear shaft 6b with end plates 23 and 24, and the bearing 14 and the seal member 1 are placed between the end plate 23 and the rear shaft 6b.
A bearing 15 is interposed between the end plate 24 and the rear shaft 6b.
and a seal member 17 is interposed. A guide ring 25 is interposed between each inner clutch plate 21 and is located on the inner side of the outer clutch +Fi 20 to define the interval between the inner clutch plates 21. The sealed oil chamber 19 is filled with highly viscous oil and a small amount of air to allow the oil to expand.
6, the filling opening 26 is closed with a screw plug 27.

In FIG. 4 (al), the outer clutch plate 20 has a large number of teeth 2 that engage with the splines 28 of the clutch outer 18.
9 and a large number of oil holes 30 that allow oil to flow through. Also, in Fig. 4 (bl), the inner clutch plate 2
1 is provided with a large number of teeth 32 that engage with the spline 31 of the rear half shaft 6b, and a large number of oil grooves 33 that allow oil to flow.

In the differential limiting clutch 7, when relative rotation occurs between the clutch outer 18 and the rear shaft 6b, the outer clutch plate 20 and the inner clutch plate 21 rotate relative to each other while shearing the high viscosity oil interposed between them. rotate.

At this time, the oil holes 30 and oil grooves 33 of each clutch plate 20.21 retain oil and contribute to effective shearing of the oil. When the oil temperature is relatively low, clutch outer 1
8 and the rear shaft 6b is determined by the shear torque of the oil.

When the rotational speed difference between the clutch outer 18 and the rear shaft 6b increases, the oil gets trapped in the shear energy received from both clutch plates 20 and 21 and increases in temperature, and initially the oil is transferred due to a decrease in viscosity as the oil temperature rises. Torque decreases. However, when the relative rotational speed exceeds a predetermined value, a complicated temperature gradient occurs in each clutch plate 20, 21 due to a sudden rise in oil temperature, resulting in distortion and an increase in pressure in the sealed oil chamber 19 due to the sudden rise in oil temperature. Due to the synergistic effect, a frictional engagement part or a part with an extremely small gap is created between the two adjacent latch temporary parts 20 and 21, and as a result, the clutch outer 18 and the rear half shaft 6b are in a substantially compressed state. Thus, the relative rotation of the clutch outer 18 and the rear half shaft 6b is controlled.

The switching clutch 8 includes a clutch inner 35 that is serrated connected to the front half shaft 6a as an input member, a clutch outer 36 that is integrally provided with the clutch outer 18 of the differential limiting clutch 7 as an output member, and a clutch inner 35 that is connected to the front half shaft 6a as an input member.
A plurality of clutch plates 37 are spline-coupled to the clutch plate 5, and a clutch outer 18 is formed by overlapping between the clutch plates 37.
It has a plurality of clutch plates 38 that are spline-coupled to the clutch plates 37 and 38, and an operating piston 39 that controls the operation of each clutch plate 37, 38, and is arranged concentrically with the front half shaft 6a.

The clutch outer 36 is connected to the end plate 24 of the differential limiting clutch 7.
It is formed into a cylindrical shape concentrically surrounding the front half shaft 6a. This clutch outer 36 and the front half shaft 6
A bearing 40 is interposed between the clutch outer 36 and the casing 9, and a bearing 41 is interposed between the clutch outer 36 and the casing 9. The clutch inner 35 has a cylindrical portion 35a that faces the inner surface of the clutch outer 36 and concentrically surrounds the front half shaft 6a, and a clutch plate 37 is spline-coupled to the outer surface of this cylindrical portion 35a. In addition, a plate 42 is fixed to the end of the cylindrical portion 35a on the opposite side of the differential limiting clutch 7 and extends outward in the radial direction.
! Both clutch plates 37.3 are placed between the pressing plate 43 and the receiving plate 42, which are disposed so as to be movable in the axial direction on the clutch 7 side.
8 are arranged in a polymerized manner.

Attach the lid 4 to the front half shaft 6a on the inner side of the clutch inner 35.
The lifter 44 and the press plate 43 are connected to each other by a plurality of connecting rods 45 that extend through the clutch inner 35 and are movable in the axial direction of the front half shaft 6a. Moreover, a coiled clutch spring 46 surrounding each connecting rod 45 is interposed between the lifter 44 and the clutch inner 35.
4 away from the clutch inner 35, that is, in a direction that brings the pressing plate 43 closer to the plate 42.

An actuating piston 39 is slidably engaged with a portion of the casing 9 on the front end side, that is, on the first shaft 4 side. The actuating piston 39 is formed into a hollow cylindrical shape in which a large diameter portion 39a and a small diameter portion 39b are coaxially connected via a stepped portion 39C, and concentrically surrounds the front half shaft 6a. Moreover, the front end side portion of the casing 9 is formed to correspond to the outer surface shape of the actuating piston 39, and the portion corresponding to the large diameter portion 39a is provided with a large diameter portion 39a.
A sealing member 47 is disposed in sliding contact with the outer surface of the small diameter portion 3.
A sealing member 48 that slides into contact with the outer surface of the small diameter portion 39b is disposed at a portion corresponding to 9b.

A hydraulic chamber 49 is defined between the actuating piston 39 and the casing 9 at a portion corresponding to the stepped portion 39c and is sealed by seal members 47 and 48. Further, a release bearing 50 that can slide along the front half shaft 6a is interposed between the end of the operating piston 39 and the front half shaft 6a, and an inner ring 50a of this bearing 50 can come into contact with the lifter 44. .

Further, a key groove 51 extending in the axial direction is bored in the outer surface of the large diameter portion 39a of the actuating piston 39, and a key 52 coupled to the casing 9 is engaged with the key groove 51. Therefore, the operating piston 39 is prevented from rotating about the axis of the front half shaft 6a.

The casing 9 includes a hydraulic boat 53 connected to the hydraulic chamber 49.
A control circuit 5 is installed in this hydraulic boat 53.
A hydraulic pressure supply source 56 is connected via an oil passage 55 having a hydraulic line 55 disposed in the middle thereof. The control circuit 54 controls each wheel Wf, Wf;Wr
, Wr (7) 1') For example, when one of the front wheels wr, wr is about to lock, the hydraulic pressure from the hydraulic pressure supply source 56 is supplied to the hydraulic chamber 49, and normally the hydraulic pressure in the hydraulic chamber 49 is released. configured to do so.

In such a switching clutch 8, when hydraulic pressure is applied to the hydraulic chamber 49, the actuating piston 39 moves toward the differential limiting clutch 7, the pressing plate 43 is operated to separate from the receiving plate 42, and the front half shaft 6
a and the clutch outer 36 are cut off. Further, during normal operation when the hydraulic pressure in the hydraulic chamber 49 is released, the clutch spring 46 acts to suppress the pressing plate 43 toward the plate 42 side, and the front half shaft 6a and the clutch outer 36 are connected.

Referring again to FIG. 2, the intermediate shaft 6 is disposed within a tunnel-shaped reinforcing rib 57 formed on the floor plate Ba of the vehicle body B along its longitudinal axis toward the passenger compartment, and is used for power transmission. , the casing 9 containing the shutoff device 1 is also arranged within the reinforcing ribs 57 . Furthermore, support arms 5B and 59 are integrally provided at both the front and rear ends of the casing 9, and these support arms 58 and 59 are connected to the floor plate B via rubber mounts 1-60 and 61.
Supported by a.

Next, the operation of this embodiment will be explained. When the engine E is operated to drive the vehicle, the power is transmitted to the front differential Df and the transfer T via the transmission M. The power transmitted to the front differential device Dr is transmitted to the left and right front axles Af.

It is transmitted to the front wheels wr1wr through Af, and both front wheels Wf, W
r is activated.

On the other hand, in normal operating conditions, the hydraulic pressure in the hydraulic chamber 49 is released and the switching clutch 8 is in the power transmission state, so the power transmitted to the transfer T is transmitted via the propulsion shaft S and the differential limiting clutch 7. Rear difference +) Attempt to drive J device Dr.

By the way, the road surface condition is good and the front wheel Wr, which is the driving wheel,
, when the slippage of Wf with the road surface is extremely small, the front wheel W
f, Wf and the rotational speed difference between the rear wheels Wr, Wr, and therefore the clutch outer 18 directly connected to the front half shaft 6a of the intermediate shaft 6.
Since the relative rotational speed between the second half shaft 6b and the second half shaft 6b is small, the transmitted torque of the differential limiting clutch 7 is small. Therefore, the front half shaft 6a, that is, the clutch outer 18, cannot drive the second half shaft 6b, and relative rotation of the two-handed shafts 6a, 6b is allowed due to mutual slippage of the two latch 20, 21. Therefore, when the vehicle turns, the front wheels Wf.

Even if the turning radii of Wf and rear wheels Wr and Wr are significantly different, by causing the differential limiting clutch 7 to slip, each wheel WE, Wr; Wr, Wr is prevented from slipping on the road surface. while allowing the vehicle to turn smoothly.

However, when the road surface condition is poor, such as on muddy ground, sandy ground, or snowy ground, and the front wheels wr, wr begin to slip violently on the road surface, the rotational speed difference between the front wheels Wf, Wf and the rear wheels Wr, Wr, Therefore, when the relative rotational speed between the two-handed shafts 6a and 6b increases rapidly and exceeds a predetermined value, the differential limiter
The chia automatically enters the coupling state, rapidly increasing its transmitted torque. As a result, the J force is transmitted to the transfer T, and is further transmitted to the rear differential device Dr via the propulsion shaft S and the differential limiting clutch 7, and further transmitted to the left and right rear axles Ar, and then to the left and right rear wheels Wr. , Wr, and the rear wheels Wr, Wr are driven. Therefore, the @transport wr9wr and the rear wheel W (Wr) are almost rigidly connected, and the vehicle can run on a road surface with poor conditions.

In this way, with the front wheels wr', wr and the rear wheels Wr, Wr connected almost rigidly, the front wheels W are
Assume that one of r and l//f is locked. In this case, while one front axle A is stopped, the other front axle A is rotating, so the rotational speed of the first axle 4 is reduced to half of what it was before one front axle Af stopped. However, since the rear wheels Wr and Wr are not locked, the rear wheels Wr and Wr
r tries to rotate at the same speed as the vehicle speed. That is, the second shaft 5 attempts to rotate at twice the speed of the first shaft 4.

However, since the first shaft 4 and the second shaft 5 are connected almost rigidly, the second shaft 5 has a rotational speed corresponding to the rotational speed of the front wheels wr, wr, which have a stronger braking force. This is the rear wheel Wr.
, Wr rotation speed is 2 times the vehicle speed, which means that the rear wheels Wr, Wr will slip against the road surface, and the rear wheels Wr, Wr will be in a locked state. .

However, when one of the front wheels wr, wr is about to lock, hydraulic pressure acts on the hydraulic chamber 49 of the switching clutch 8, and the switching clutch 8 enters the disconnected state. Therefore, the front wheel Wf,
The substantially rigid connection state between Wf and the rear wheels Wr, Wr is released, and the rear wheels Wr, W'' are prevented from becoming locked.

Next, while the vehicle is running, the power unit P
The rear wheel W r may vibrate or the rear wheel may vibrate due to unevenness of the road surface.

Suppose that W' moves up and down. In this case, in the propulsion shaft S, the first shaft 4 and the second shaft 5 are at the joint J3.
By simply swinging around J4, the relatively heavy power transmission/cutoff device 1, which is comprised of the differential limiting clutch 7 and the switching clutch 8, is supported by the floor plate Ba of the vehicle body B.

Therefore, the swinging weight of the tli advance shaft S can be minimized, and the occurrence of vibration due to the swinging can be suppressed to a small level.

Further, since the power transmission and cutoff device 1 is housed in a tunnel-shaped reinforcing rib 57 supported by the floor plate Ba of the vehicle body B, the power transmission and cutoff device 1, that is, the differential limiting clutch 7
Also, the ground clearance of the switching clutch 8 can be maximized. Moreover, the differential limiting clutch 7 and the switching clutch 8
is effectively cooled by the traveling wind passing through the reinforcing ribs 57, so overheating due to internal frictional heat can be prevented. Moreover, the above frictional heat is
and 1st. Since it is blocked by the second axis 4.5, the transfer T and rear differential value r! Thermal influence on the lDr can be suppressed.

Further, since the switching clutch 8 is disposed concentrically with the four half shafts 6a constituting the propulsion shaft S, it is possible to dispose them together in a compact manner in the middle of the propulsion shaft S. In addition, the actuating piston 39 is hollow and surrounds the front half shaft 6a, and defines a hydraulic chamber 49 between it and the fixed casing 9 and is slid onto the acid casing 9, so the sealing structure is the front wheel.
The hydraulic pressure supply route to the hydraulic chamber 49 is also simple.

Since the differential limiting clutch and the switching clutch 8 that constitute the power transmission and cutoff device 1 are connected in series and commonly housed in the casing 9, they can be more compactly assembled than if they were arranged separately. This can contribute to miniaturization of the entire drive device.

FIG. 5 shows another embodiment of the present invention, and parts corresponding to those in the previous embodiment are given the same reference numerals.

In a full-time four-wheel drive vehicle equipped with a center differential, lock the center differential and drive the front wheels wr, wr and the rear wheels wr, wr.
This embodiment is applied when the front wheels wr, wf and the rear wheels Wr, Wr are rigidly connected in a part-time four-wheel drive vehicle. The shaft 6a and the rear shaft 6b are connected via a switching clutch 8'.

The first half shaft 6a as an input member is rotatably supported by the casing 9' via bearings 65, 66 and a seal member 67, and the second half shaft 6b as an output member is rotatably supported by the casing 9' via bearings 68 etc. supported by. Furthermore, the ends of the two half shafts 5a, 5b are coaxially opposed within the casing 9'.

The switching clutch 8' includes a clutch inner 35' coupled to the rear half shaft 6b with a bearing 69 interposed between the front half shaft 6a and a clutch outer 35' spline coupled to the half shaft 6a.
6', a plurality of clutch plates 37 spline-coupled to the clutch inner 35', a plurality of clutch plates 37 overlapped between these clutch plates 37 and spline-coupled to the clutch outer 36', and a pressing plate 43. ' and press plate 4
a clutch spring 46' interposed between the clutch outer 36' and the lifter 44';
and an actuating piston 39'.

The clutch inner 35' extends from the rear shaft 6b to concentrically surround the end of the front shaft 6a. Further, the clutch outer 36' has a small diameter cylindrical part 70 spline-coupled to the front half shaft 6a, and a large diameter cylindrical part 71 concentrically surrounding the clutch inner 35'. The receiver is connected to a press plate 4 connected to one end of the lifter 44' so as to be able to move toward and away from the member 72.
3' and the plate part 72, each clutch plate 37°38
are arranged in a polymerized manner. Further, the lifter 44' is disposed so as to concentrically surround the clutch outer 36' and is movable in the axial direction, and the other end of the lifter 44' and the clutch outer 36'
A clutch spring 46' that biases the pressing plate 43' toward the plate portion 72 is interposed between the clutch spring 46' and the clutch spring 46'.

The operating piston 39' is accommodated in the casing 9', defining a hydraulic chamber 49 therebetween, and a key 52' provided in the casing 9' is engaged with the operating piston 39'. The casing 9 is placed at a position W with the hydraulic chamber 49 in between.
A sealing member 73.7 is provided between the
4 is interposed. Moreover, the operating piston 39' is the front half shaft 6
It is formed into a hollow cylindrical shape concentrically surrounding a, and a release ring 75 is interposed between one end of the operating piston 39' and the lifter 44'. Therefore, in response to the operation of the actuating piston 39', the lifter 44', that is, the pressing plate 4
3' moves in the axial direction.

In this embodiment as well, the switching clutch 8' has front wheels Wf,
When one side of Wf is about to lock, shut off and lock the rear wheel W.
Prevent locking of r and Wr. Also, the operating piston 39'
The seal structure is simplified, the hydraulic pressure supply path is simple, and the entire switching clutch 8' can be made compact.

C0 Effects of the Invention As described above, according to the present invention, the switching clutch includes a plurality of clutch plates that are alternately stacked and spline-coupled to the clutch inner and clutch outer that are respectively coupled to either the input or output member. , a clutch spring that biases each clutch plate in the direction of frictional engagement, and an operating piston that temporarily operates the clutch plates, and is concentrically mounted on a propulsion shaft that connects the power unit and the other wheel. placed,
The actuating piston defines a hydraulic chamber between the fixed support body that rotatably supports the propulsion shaft, is fitted to the support body, and has a hollow shape that concentrically surrounds the propulsion shaft. Since the switching clutch is formed in a compact manner around the propulsion shaft, it is possible to contribute to miniaturization of the drive device.

In addition, a hydraulic power source is connected to the hydraulic chamber to supply hydraulic pressure to the operating piston in a timely manner, making use of the advantage of four-wheel drive vehicles in shortening braking distance. For example, it is possible to reliably prevent the rear wheels from locking when the front wheels are locked.

[Brief explanation of the drawing]

Figures 1 to 4 show one embodiment of the present invention.
The figure is a longitudinal plan view of a part of the drive system of an automobile, Figure 2 is a side view thereof, Figure 3 is an enlarged vertical cross-sectional view of the power transmission and disconnection device in the drive system, and Figure 4 is a differential limiting clutch. FIG. 5 is a plan view of the outer and inner clutch plates in FIG. 6a... First half shaft as input member, 6b... Second half shaft as output member, 8.8'... Switching clutch, 9°9'... Casing as support body, 35.35'.
...Thalassochin inner, 36.36' ...Clutch outer, 37.38...Clutch plate, 39.39'
... Working piston, 49... Hydraulic chamber, 56... Hydraulic supply source, P... Power unit, S... Propulsion shaft, W
f...Front wheel, Wr...Rear wheel

Claims (1)

[Claims] A power unit is connected to either the front or rear wheel to constantly drive the wheel, and a power transmission mechanism is provided between the power unit and the other wheel, which can be rigidly connected to the one wheel. In a drive system for a four-wheel drive vehicle that is equipped with a switching clutch that can switch between disconnection and disconnection,
A switching clutch includes a plurality of clutch plates that are alternately stacked and spline-coupled to a clutch inner and a clutch outer that are respectively coupled to either an input or an output member, and a clutch that biases each clutch plate in the direction of frictional engagement. spring and
The operating piston is arranged concentrically on the propulsion shaft that connects the power unit and the other wheel, and the operating piston is a fixed support that rotatably supports the propulsion shaft. The hydraulic chamber is slidably fitted to the support and is formed in a hollow shape concentrically surrounding the propulsion shaft, and the hydraulic chamber has hydraulic pressure to press the actuating piston toward the power cutoff side at appropriate times. A drive device for a four-wheel drive vehicle, characterized in that a hydraulic supply source for supplying the same is connected.