JPH0645308B2 - Full-time four-wheel drive vehicle - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full-time four-wheel drive vehicle that always drives four wheels with front and rear wheels, and particularly, between a transmission and a rear wheel side or front wheel side differential device. The present invention relates to a system in which a multi-plate clutch is provided.

<Prior Art> A four-wheel drive vehicle using a multi-plate clutch is disclosed in Japanese Patent Laid-Open No. 58-
There is one shown in No. 26636. This one normally engages the clutch plate on the front wheel side and the clutch plate on the rear wheel side in the state of a half clutch by the force of the spring,
When a large transmission torque is required, the piston is hydraulically operated, and the front wheel side clutch plate and the rear wheel side clutch plate are integrally connected by the pressing force of the piston and the spring.

<Problems to be Solved by the Invention> This problem has a problem that a large clutch plate is required to transmit a high transmission torque to the rear wheels. On the contrary, if a small clutch plate is used, a very high hydraulic pressure must be supplied to the piston, which causes a problem that power loss of the engine for driving the pump increases.

<Means for Solving Problems> The present invention has been made to solve the above-mentioned problems, and provides a multi-spindle between the input shaft on the transmission side and the output shaft on the rear wheel side or the front wheel side differential gear side. A plate clutch and a direct coupling clutch are provided in parallel, and the multi-plate clutch includes an input shaft clutch plate provided on the input shaft, an output shaft clutch plate provided on the output shaft, an input shaft clutch plate and an output shaft clutch. The direct coupling clutch is composed of a pressure contact pist that presses a plate, and the direct coupling clutch is provided on one of the input shaft and the output shaft so as to be capable of advancing and retracting in the axial direction and relatively non-rotatable, and the piston body and the input shaft and the output shaft. Of the teeth, which are provided on the other side of the piston and mesh with each other so as to be capable of transmitting rotation, and a piston, which is provided between the piston body and the other of the input shaft and the output shaft, releases the meshing of the teeth. A control means for controlling the pressure of the same fluid acting on the pressure contact piston and the piston body according to the traveling state is provided.

<Operation> With the configuration described above, the pressure is controlled by one control unit according to the traveling state. When a large transmission torque is not required, the pressure is reduced to transmit the rotational power of the engine to the rear wheel side or front wheel side differential device via a multi-plate clutch, and a large transmission is generated such as during sudden start or sudden braking. When torque is required, the pressure is increased to operate the direct coupling clutch in the direct coupling direction, and the rotational power of the engine is transmitted to the rear wheel side or front wheel side differential device via the direct coupling clutch.

<Example> An example of the present invention will be described below with reference to the drawings. In FIG. 2, reference numeral 10 denotes an engine, and a transmission 11 is connected to the engine 10. A drive gear 13 is formed at one end of the output shaft 12 of the transmission 11, and the drive gear 13 has a rotational power transmission shaft 14
It is meshed with the gear 15 formed in. Bevel gears 16, 17 are formed at both ends of the rotary power transmission shaft 14, one bevel gear 16 meshes with a bevel gear 21 of a front wheel side differential device 20, and the other bevel gear 17 has a bevel gear 23 of a rear wheel side differential device 22. Meshes with. The rotational power transmitted to the front wheel side differential device 20 is rotated by the front wheel drive shaft 24.
The rotational power transmitted to the front wheels 25 via the rear wheel side differential device 22 is transmitted to the rear wheels 27 via the rear wheel side drive shaft 26. A clutch 30 is provided on the rotary power transmission shaft 14 on the rear wheel side differential device 22 side. Reference numeral 31 is the rotary power transmission shaft 14 before the clutch 30, that is, the input shaft, and 32 is the rotary power transmission shaft 14 after the clutch 30, that is, the output shaft.

The clutch 30 has a clutch case 40 as shown in FIG.
The clutch case 40 is fixed to a body (not shown). The clutch case 40 has a bearing 41,
An input shaft 31 and an output shaft 32 are coaxially and rotatably supported via 42, and a multi-plate clutch 43 and a direct coupling clutch 44 are provided in parallel between the input shaft 31 and the output shaft 32. The multi-plate clutch 43 includes an input shaft clutch plate 46 provided on the inner circumference of a cylindrical portion 45 of the input side 31 and an output side clutch plate 48 provided on the outer circumference of a cylindrical portion 47 of the output shaft 32.
And a pressure contact piston 49 slidably fitted in a cylinder chamber 56 formed in the input shaft 31. The input side clutch plates 46 and the output side clutch plates 48 are provided so as to be alternately overlapped with each other.
The input side clutch plate 46 and the output side clutch plate 48 are pressed into contact with each other, whereby the rotation of the input shaft 31 is transmitted to the output shaft 32 via the multi-plate clutch 43. Further, the input side clutch plate 46 and the output side clutch plate 48 are of a size such that slip does not occur during normal starting.

The direct coupling clutch 44 includes a piston body 51 provided on the input shaft 31 via an spline 50 so as to be movable only in the axial direction,
The piston body 51 includes external teeth 52, internal teeth 53 formed on the output shaft 32 so as to be able to mesh with the external teeth 52, and a spring 54 inserted between the piston body 51 and the output shaft 32. There is. The outer teeth 52 and the inner teeth 53 can mesh with the input shaft 31 at a plurality of angular positions of the output shaft 32. By engaging the outer teeth 52 and the inner teeth 53,
The rotation of the input shaft 31 can be transmitted to the output shaft 32. A cylinder chamber 55 is formed in the input shaft 31 on the side opposite to the spring 54, to which pressure oil for pressing the pistol body 51 toward the output shaft 32 is supplied.

Reference numeral 60 denotes a pump driven by the engine 10. The discharge amount of the pump 60 is controlled to a constant amount by a flow rate control valve built in the pump. The discharge flow rate from the pump is divided into a constant flow rate by the flow control valve 61 between the power steering device and the clutch 30. The diversion control valve 61 and the clutch 30 communicate with each other via a passage 62, and the clutch 30
The pressure oil guided to is introduced into the cylinder chamber 55 via the introduction passages 63 and 64 formed in the clutch case 40 and the input shaft 31. The pressure oil introduced into the cylinder chamber 55 is also introduced into the cylinder chamber 56 of the multi-plate clutch 43 via the communication passage 65. In addition, the passage 62 is
It communicates with a reservoir tank 67 via an electromagnetic variable throttle valve 66. By adjusting the opening degree of the passage by the electromagnetic variable throttle valve 66, the pressure of the pressure oil supplied to the cylinder chambers 55, 56 is controlled. It

A control device 70 controls the current supplied to the solenoid of the electromagnetic variable throttle valve 66.
A steering angle signal θ of the steering wheel, a vehicle speed signal v, and an on / off signal indicating whether or not the accelerator pedal or the brake pedal is depressed to a predetermined position are input to the. Pump 60, electromagnetic variable throttle valve 66, controller 7
Control means 80 for operating the direct coupling clutch 44 with 0
Is configured.

Next, the operation will be described based on the configuration described above. During normal traveling that does not require high transmission torque, the pressure oil supplied to the cylinder chambers 55 and 56 is controlled to a pressure according to the vehicle speed v and the steering angle θ. That is, when turning, the pressure is low,
The control is performed so that the pressure increases when going straight, and the pressure increases as the vehicle speed increases. As a result, the output side clutch plate 48 and the input side clutch plate 46 are brought into pressure contact with each other by the pressure contact piston 49 according to the pressure supplied to the cylinder chamber, and the friction between the output side clutch plate 48 and the input side clutch plate 46 causes the input shaft to move. The rotational power of 31 is transmitted to the output shaft 32. At this time, the piston body 51 is retracted by the spring 54, and the outer teeth 52 and the inner teeth 53 are not meshed. Therefore, at the time of turning, the difference in rotational speed between the front wheels and the rear wheels is absorbed by the multi-plate clutch 43, and the tight braking phenomenon does not occur.

When high transmission torque is required, such as during sudden start or sudden braking, the pressure oil supplied to the cylinder chambers 55, 56 should be
Control to the highest pressure. As a result, the piston body 51 overcomes the spring 54 and moves to the right, and the outer teeth 52 and the inner teeth 5
3 mesh. The input side clutch plate 46 and the output side clutch plate 48 are pressed against each other with a high pressing force. In this state, the rotational power of the input shaft 31 is transmitted to the output shaft 32 via the multiple disc clutch 43 and the direct coupling clutch 44 without slipping.

When a high transmission torque is required as described above, the rotational power is transmitted through the direct coupling clutch 44, so that the input side clutch plate 46 and the output side clutch plate 48 may have a size such that slip does not normally occur at the time of starting, The outer diameter dimensions of the clutch plate 46 and the output side clutch plate 48 can be made smaller than in the conventional case.

In the above-described embodiment, as an example requiring a high transmission torque, when the vehicle is suddenly started or suddenly braked, the direct coupling clutch is operated in the direct coupling direction during the uphill and the downhill where engine braking is required. Is also good.

<Effects of the Invention> As described above, according to the present invention, the multiple disc clutch and the direct coupling clutch are provided in parallel between the transmission and the rear wheel side or front wheel side differential device, and the direct coupling clutch is used when high transmission torque is required. Since the control means for actuating in the direct coupling direction is provided, the multi-disc clutch need only be large enough to prevent slippage during normal transmission, and has the advantage of reducing the size of the multi-disc clutch.
Moreover, since very high hydraulic pressure is not required, there is an advantage that less power is required to drive the pump. Further, since the control means can automatically switch between the multiple disc clutch and the direct coupling clutch, the driver's operation becomes unnecessary. Furthermore, since the pressure contact piston of the multi-plate clutch and the piston body of the direct coupling clutch are operated by one control means, an effect that the configuration is simplified can be obtained.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a sectional view showing the internal structure of a clutch, and FIG. 2 is a power system diagram. 10 ... Engine, 11 ... Transmission, 20
... front wheel side actuating device, 22 ... rear wheel side differential device, 30 ...
... clutch, 43 ... multi-plate clutch, 44 ... direct coupling clutch, 80 ... control means.

Claims (1)

[Claims] 1. A four-wheel drive vehicle in which rotational power of an engine is transmitted to a front wheel side differential device and a rear wheel side differential device via a transmission, and a difference between an input shaft on the transmission side and a rear wheel side or a front wheel side. A multiple disc clutch and a direct coupling clutch are provided in parallel between the output shafts of the moving device side, and the multiple disc clutch includes an input shaft clutch plate provided on the input shaft, and an output shaft clutch plate provided on the output shaft. The input clutch and the output shaft clutch plate are in pressure contact with each other, and the direct coupling clutch is provided on one of the input shaft and the output shaft so as to be capable of advancing and retracting in the axial direction and non-rotatable relative to each other. Teeth provided on the other of the piston body and the input shaft and the output shaft and meshing with each other for rotation transmission, and between the piston body and the other of the input shaft and the output shaft. A control means for controlling the pressure of the same fluid acting on the pressure contact piston and the piston body according to the running state, the control means comprising a spring for urging the piston body in the direction to release the meshing of the teeth. Is a full-time four-wheel drive vehicle.