JPH01141240A - Driving force transmitting device - Google Patents

Abstract

PURPOSE:To obtain the transmission torque characteristic proper for the traveling condition by installing a solenoid valve for controlling the throttle opening degree according to the traveling condition such as car speed into a communication passage for discharging oil from a high pressure space part side to a low pressure space part side on the basis of the relative revolution speed difference between the front and rear wheel driving shafts. CONSTITUTION:When front/rear wheel driving shafts 12 and 20 relatively revolve, and a rotor 41 revolves in a cylinder housing 31, the high viscosity oil charged into a space part is forcibly shifted at the flow speed corresponding to the revolution speed difference between the both edge surfaces of the cylinder housing 31 and a working piston 36 by a vane 42. Then, an internal pressure is generated by the viscous friction, and the working piston 36 presses a multiple disc clutch 40, and a revolution torque is transmitted to the rear wheel driving shaft 20 from the front wheel driving shaft 12. Thought the high viscosity oil is discharged into a low pressure space side from a high pressure space side through the communication passages 50 and 51, the discharge quantity is controlled according to the throttle area of a solenoid valve 52 whose throttle opening degree is controlled according to the traveling condition such as car speed. Therefore, the transmission torque characteristic proper for the traveling condition can be automatically controlled.

Description

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

<Prior Art> Conventionally, an oil pump is driven by a rotational speed difference between two drive shafts connected to a front wheel side and a rear wheel side, and a discharge pressure of the oil pump corresponding to this rotational speed difference is used to drive both parts. A four-wheel drive vehicle equipped with a hydraulic clutch that engages and releases a shaft is known, for example, as described in Japanese Patent Application Laid-Open No. 60-252026.

In such a torque transmission device for a four-wheel drive vehicle, the front wheel l
I! A 1-land gear or vane type oil pump is installed between the I drive shaft and the rear wheel drive shaft, and the oil pump discharges pressure oil according to the relative speed of both shafts. The pressure is introduced into the cylinder chamber of the hydraulic clutch through a pressure introduction passage formed on one side of the shaft, and the hydraulic clutch is engaged.

<Problems to be Solved by the Invention> However, in this type of torque transmission device, it is necessary to incorporate an oil pump between the front wheel drive shaft and the rear wheel drive shaft. It is necessary to form a passage for introducing the discharged oil into the hydraulic clutch, which results in a complicated structure, large size, and high cost.

Means for Solving the Problems> The present invention has been made in view of the above-mentioned problems of the conventional art. In a driving force transmission device for a four-wheel drive vehicle, which includes a multi-disc clutch that transmits torque, and an operating piston that controls transmission torque of the multi-disc clutch, a cylinder housing that accommodates the operating piston is restricted between the An axial clearance is provided on the side of the actuating piston, a thin-walled rotor is housed in this axial clearance, the rotor is connected to either the front wheel drive shaft or the rear wheel drive shaft, and the cylinder housing is connected to the other one of the front wheel drive shaft or the rear wheel drive shaft. are connected to each other, a plurality of blades are provided on the circumference of the rotor, the space is divided into a plurality of areas on the circumference by these blades, and high viscosity oil is sealed in each of the spaces, and high viscosity oil is sealed in the space. A communication passage is provided to release the high-viscosity oil from the high-pressure space side to the low-pressure space side based on the relative rotational speed difference between the front wheel drive shaft and the rear wheel drive shaft. This is equipped with a solenoid valve that controls the throttle opening.

With the above configuration, when the front wheel drive shaft and the rear wheel drive shaft rotate relative to each other and the rotor rotates within the cylinder housing, the high viscosity oil sealed in the space defined by the rotor blades fills the gap. Due to the forced movement, the pressure of the high viscosity oil in the space increases in accordance with the relative rotational speed, presses the working piston, joins the multi-plate flanch, and creates a four-wheel drive state.

Also, is it the high pressure space side based on the relative rotational speed? A solenoid valve controls the release of high-viscosity oil that escapes to the low-pressure space side through a communication path, thereby obtaining transmission torque characteristics that correspond to driving conditions such as vehicle speed.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. In FIG. 4, reference numeral 10 indicates an automobile engine, and the rotational output of this engine 10 is transmitted to 1 through a transmission 11.
The rotation of this 1 (μ drive shaft 12) is transmitted to the left and right front wheels 15.1 via the front wheel side differential device 13.
6 can be conveyed.

A rear wheel drive shaft 20 is connected to the front wheel drive shaft 12 via a driving force transmission device 30 configured to be described later, and the rotational torque transmitted to the drive shaft 20 is then transmitted to the rear wheel differential device 21.
It is transmitted to the left and right rear wheels 23, 24 via the

The specific configuration of the 1q driving force transmission device 30 will now be described.6 In FIG. The front wheel drive shaft 12 is rotatably housed within a cylindrical fixed housing 32, and the front wheel drive shaft 12 is rotatably supported at one end of the fixed housing 32. A cap 3 is attached to the other end of this fixed housing 32.
3 is fixed to the cylinder housing 31, and a cap 34 is also fixed to the other end of the cylinder housing 31. Both camps 33
．． 34, one end of the f&width drive shaft 20 is connected to the front wheel drive shaft 1.
It is rotatably supported coaxially with 2.

A plurality of clutch plates 37 are spline engaged with the inner periphery of the cylinder housing 31, and the rear wheel drive shaft 20
A plurality of clutch plates 38 are spline engaged with the outer periphery of the clutch plate 38 . These two clutch plates 37, 38 are arranged alternately to form a multi-disc clutch 40. Further, within the cylinder housing 31, an operating piston 36 is slidably fitted between the multi-disc clutch 40 and the cylinder housing 31, and the hydraulic pressure acting on the operating piston 36 causes the reflatch plates 37, 38 to move. Pressed. Therefore, the one-stroke torque transmitted from the front wheel drive shaft 12 to the cylinder housing 31 is transmitted to the rear wheel drive shaft 20 via the clutch plates 37 and 38. This transmitted torque is transferred to the working piston 3.
It changes according to the hydraulic pressure acting on 6.

A slight axial gap is provided on the side of the actuating piston 36 with the end wall of the cylinder housing 31, and a thin-walled rotor 41 having a wall thickness equal to that gap and time slides into this axial gap. possible storage. Such a rotor 41
As shown in FIG. 2, the center portion thereof is spline-engaged with the outer periphery of the rear wheel drive shaft 20, and has a plurality of circumferential blades 42 extending in the radial direction. The outer ends of these vanes 42 are operatively fitted into the inner periphery of the cylinder housing 31 to form a seal. As a result, a plurality of spaces 43 partitioned in the circumferential direction by the plurality of blades 42 are formed in the axial gap between the actuating piston 36 and the cylinder housing 31, and these spaces 43 are filled with high viscosity oil such as silicone oil. It is filled with oil 44.

Further, the cylinder housing 31d moves the high-viscosity oil 44 sealed in the space 43 from the high-pressure space side to the low-pressure space side based on the rotation of the rotor 41 due to the relative rotation between the front wheel drive shaft 12 and the rear wheel drive shaft 20. Communication path 50 for releasing to
．． 51 is provided, and a solenoid valve 52 is provided between the communication paths 50 and 51 to throttle and control the amount of the high viscosity oil 44 that escapes. This solenoid valve 52 is controlled by a current value (■) from a controller 53, and this current friI is controlled by calculating signals of driving conditions such as vehicle speed, steering wheel angle, and road surface condition inputted to the controller 53 by the controller 53. be.

With the above configuration, the front wheel drive shaft 12 and the rear wheel drive shaft 20
When the rotor 41 rotates within the cylinder housing 31 through relative rotation, the high viscosity oil 44 sealed in the space 43 is forced to move between the two closely spaced surfaces at a flow rate corresponding to the rotational speed difference. be done. At this time, internal pressure is generated due to viscous friction between the cylinder housing 31 and both end surfaces of the actuating piston 36. This internal pressure presses the actuating piston 36 in a direction that presses against the multi-disc clutch 40, and one rotational torque is delivered from the front wheel drive shaft 12 to the rear wheel drive shaft 2o.

Therefore, when driving on a low μ road such as a muddy or snowy road, if the front wheels 15.16 or the rear wheels 23.24 slip and the relative rotational speed difference between the front wheel drive shaft 12 and the rear wheel drive shaft 2o increases. The internal pressure generated in the space 43 also increases, resulting in four-wheel drive, and since the relative rotational speed difference between the front wheel drive shaft 12 and the rear wheel drive shaft 20 is small during normal cornering, the pressure generated in the space 43 increases. Since the internal pressure is also reduced, the clutch plates 37 and 38 of the multi-disc clutch 40 slip, thereby preventing the braking phenomenon from tie 1 to corner.

The transmission torque characteristics described above change depending on driving conditions such as vehicle speed. That is, based on the rotational speed difference, the high viscosity oil 44
is released from the high pressure space side to the low pressure space side through the communication passages 5o and 51, but the amount of high viscosity oil 44 released is controlled by the throttle area of the electromagnetic valve 52 whose throttle opening degree is controlled by driving conditions such as vehicle speed. Ru. Therefore, as shown in Figure 3,
When the constriction area of the solenoid valve 52 is large, the transmitted torque is slightly reduced as shown in curve A, and when the constricted area of the solenoid valve 52 is small, a large transmitted torque is obtained as shown in curve 8. This automatically controls transmission torque characteristics appropriate to the driving conditions.

Further, in the above-described embodiment, an example of an FF vehicle in which torque is transmitted from the front wheel side to the rear wheel side has been described, but it is of course applicable to an FR vehicle as well, and the rotor 41
may also be connected to the cylinder housing 31 side.

<Effects of the Invention> As described above, the present invention provides a gap limited in the axial direction on the side of the actuating piston that controls the multi-disc clutch, and a thin wall with approximately the same thickness as the gap. The rotor is housed, and high viscosity oil is filled in multiple spaces divided by the rotor blades, and the internal pressure generated in the spaces is activated according to the relative rotational speed difference between the front wheel drive shaft and the rear wheel drive shaft. Since the structure is such that the torque is applied directly to the piston, there is no need for substantial space to incorporate a means for generating pressure that acts on the working piston, and the torque transmission device can be made extremely compact. The configuration is simple.Furthermore, based on the relative rotational speed difference between the front drive wheels and the rear drive shaft, high viscosity oil is released from the high-pressure space side to the low-pressure space side via a communication path, and the amount of this release can be adjusted based on the vehicle speed, etc. Since the configuration is such that the control is performed using a solenoid valve according to the driving conditions, it is possible to provide transmission torque characteristics appropriate to the driving conditions.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view showing a driving force transmission device for a four-wheel drive vehicle, and FIG.
3 is a transmission torque characteristic diagram by the device of the present invention, and FIG. 4 is a schematic diagram of a vehicle in which the device of the present invention is installed. 12...Front wheel drive shaft, 15.16...Front wheel, 20.
...Rear wheel drive shaft, 23.24...t & wheel, 30...
Drive force transmission device, 36... Working piston, 37.38
...Clutch plate, 40...Multi-plate clutch, 41...
・Rotor, 42...Blade, 43...Space part, 44・
...High viscosity oil, 50.51...Communication path, 52...Solenoid valve, 53...Controller.

Claims (1)

[Claims] Driving a four-wheel drive vehicle comprising a multi-disc clutch disposed between a front-wheel drive shaft and a rear-wheel drive shaft and transmitting torque between the two shafts, and an operating piston that controls the transmission torque of the multi-disc clutch. In the force transmission device, a limited axial clearance is provided on the side of the working piston with a cylinder housing that houses the working piston, a thin-walled rotor is housed in this axial clearance, and this rotor is connected to the front wheel drive shaft. and a rear wheel drive shaft, and the cylinder housing is connected to the other, and a plurality of blades are provided on the circumference of the rotor, and the space is divided into a plurality of areas on the circumference by these blades. High viscosity oil is sealed in each of these spaces, and the high viscosity oil sealed in the spaces is transferred from the high pressure space side to the low pressure space based on the relative rotational speed difference between the front wheel drive shaft and the rear wheel drive shaft. 1. A driving force transmission device, characterized in that a communication path is provided on the side of the vehicle, and a solenoid valve is provided in the communication path to control the opening degree of the throttle according to driving conditions such as vehicle speed.