JPS62181924A - Drive system clutch device for vehicle - Google Patents

Abstract

PURPOSE:To secure a high clutch pressure by constituting a fluid pressure generating means feeding a fluid pressure to a drive system clutch means provided between drive input/output sections of a power dividing device as a means converting a power steering hydraulic pressure into a boosted fluid pressure. CONSTITUTION:A power dividing device which is a differential device is provided with a multi-plate friction clutch means between its drive input section and drive output section, the said means is tightened in response to the hydraulic pressure level applied to a hydraulic piston 33, thereby its differential operation is restricted. In this case, the power steering hydraulic pressure PS in response to the steering force via a control valve 43 is guided to a hydraulic pressure generating device 60 through a branch oil passage 51 via a valve device 50. The valve device 50 is constituted of solenoid valves 52, 53 controlled via the operation of a transfer mode switch 54. The hydraulic pressure generating device 60 is provided with a master cylinder-structured hydraulic pressure generating cylinder 62 and is constituted so that the said hydraulic pressure PS can be converted into a clutch hydraulic pressure PC.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a differential limiting clutch that is used in a differential device, a transfer device of a four-wheel drive vehicle, etc., and which applies clutch engagement force using external fluid pressure. The present invention relates to vehicle drive system clutch devices such as drive force distribution clutches and drive force distribution clutches.

(Prior Art) Conventional limited differential clutch devices for vehicles include, for example,
A device as described in Japanese Utility Model Application Publication No. 59-68846 is known.

This conventional device includes an operating means provided in the driver's cab, a hydraulic pressure generating device that generates hydraulic pressure by operating the operating means, and a hydraulic pressure generator that receives the hydraulic pressure generated by the hydraulic generating device and presses the side gear of the differential against the differential case. and an actuator device that acts on the differential case, and the differential limiting force of the differential device is changed by changing the pressing force of the side gear against the differential case in accordance with the hydraulic pressure generated by the hydraulic pressure generating means. It was something.

(Problems to be Solved by the Invention) However, in such conventional devices, the driver operates the operating means based on his/her preference or road condition judgment, and converts the operating force into hydraulic pressure to perform differential braking. Because the configuration was designed to obtain a crab, a very large operating force was required to obtain a high differential limiting force, and if the operating means were to be abolished, a new one would be required. There was a problem in that a hydraulic pump had to be installed as a hydraulic pressure generating device.

Therefore, it is possible to use the existing power steering pump in the vehicle as a hydraulic pressure generator, but if you want to use the power steering hydraulic pressure as it is and input it to the differential limiting clutch via the pressure reducing valve, it is necessary to use the power steering pump while steering. Even if this is not possible, install an orifice between the power steering pump and the power steering control valve to obtain the required amount of hydraulic pressure, or increase the pump capacity to increase the back pressure from the power steering pump to more than the required clutch pressure. This resulted in an increase in back pressure, which led to an increase in fuel consumption, and required changes to the power steering control valve.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above-mentioned problems, and in order to achieve this purpose, the present invention has adopted the following solving means. .

The solution of the present invention will be described with reference to the conceptual diagram of the claim shown in FIG. A drive system clutch means 4 is provided between the drive system clutch means 4 and the drive output section and generates a clutch engagement force using external fluid pressure; In a vehicle drive system clutch device comprising a fluid pressure generating means 5 for generating Pc, a power steering generated hydraulic pressure Ps from a power steering device 6 is inputted to the fluid pressure generating means 5 via a valve device 7. This is a means for converting the input power steering generated hydraulic pressure into an increased fluid pressure Pc.

(Function) Therefore, in the vehicle drive system clutch device of the present invention, as described above, the power steering hydraulic pressure from the power steering device is not directly used, but is used indirectly as the input hydraulic pressure of the fluid pressure generating means. By using it as a means to
A high clutch pressure can be obtained by increasing the pressure in the fluid pressure generating means without being limited by the pressure level of the power steering hydraulic pressure.

In addition, the power steering hydraulic pressure is a hydraulic pressure that corresponds to the steering torque, so by utilizing this hydraulic pressure change, it is possible to obtain a clutch engagement pressure that corresponds to the lateral acceleration during cornering, and a valve device is provided. It is also possible to freely control the clutch engagement pressure.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In describing this embodiment, a differential limiting clutch device for an automobile including differential limiting clutch means operated by external hydraulic pressure will be taken as an example.

First, the configuration of the embodiment will be explained.

As shown in FIGS. 2 to 4, the embodiment device includes a differential device (power split device) 10, a multi-disc friction clutch means (drive system clutch means) 11, a power steering device 2140,
Valve device 50, hydraulic pressure generating device (fluid pressure generating means) 60
Each configuration will be described below.

The differential device IO has a differential function that creates a speed difference between the left and right wheels in accordance with the difference in rotational speed in driving conditions where a difference in rotational speed occurs between the left and right wheels, and a differential function that equalizes the engine driving force to the left and right driving wheels. This is a device that has a driving force distribution function that distributes and transmits the driving force.

This differential device IO is housed in a housing 16 that is attached to the vehicle body by a stud port 15, and includes a ring gear 17, a differential case 18,
It includes a binion mate shaft 19, a differential pinion 20, and side gears 21 and 21'.

The differential case 18 includes a housing 16
It is rotatably supported by tapered roller bearings 22°22'.

The ring gear 17 is connected to a differential case 18.
The propeller shaft 23 is fixed to the propeller shaft 23, and meshes with a drive pinion 24 provided on the propeller shaft 23, from which rotational driving force is input.

The side gears 21, 21' include a left wheel drive shaft 25 and a right wheel drive shaft 2, which are drive output shafts.
6 is provided for each.

The multi-disc friction clutch means 11 is provided between the drive input section and the drive output section of the differential gear 10, and is a means to which clutch engagement force is applied by external hydraulic pressure and generates a differential limiting torque.

This multi-disc friction clutch means 11 is housed within a housing 16 and a differential case 18, and includes a multi-disc friction clutch 27.27', a pressure ring 28.28', and a reaction plate 29.29'.
, thrust bearing 30.30', spacer 31.31'
, bushing rod 32, hydraulic piston 33, oil chamber 34,
A hydraulic port 35 is provided.

The multi-disc friction clutch 27, 27' includes friction plates (27a, 27'a) fixed in the rotational direction to the differential case (drive input part) 18, and fixed in the rotational direction to the side gear (drive output part) 21, 21'. pressure rings 28 and 28' on both axial end surfaces.
and reaction plates 29, 29' are arranged.

The pressure ring 28, 28' is provided in a fitted state on the pinion mate shaft 19 as a member receiving the clutch engagement force, and the fitting portion is connected to the shaft having a rectangular cross section as shown in FIG. The end portion 19a is fitted into the square grooves 28a and 28'a, and the structure is such that no thrust force is generated due to a difference in rotation, as in a torque proportional differential limiting mechanism.

The hydraulic piston 33 moves in the axial direction (rightward in the drawing) by supplying hydraulic pressure to the hydraulic port 35, and engages both the multi-disc friction clutches 27, 27' according to the hydraulic pressure level. In the clutch 27, the engagement force is transmitted from the bushing rod 32 to the spacer 31 to the thrust bearing 30 to the reaction plate 29, and the pressure ring 2
8 as a reaction force receiver, and the other multi-disc friction clutch 27' is fastened using the fastening reaction force from the housing 16 as a fastening force.

The power steering device 40 is a device that uses hydraulic pressure to power assist the steering force during steering using the steering wheel 41, and includes an oil pump 42, a control valve 43. A power cylinder 44 is provided.

The oil pump 42 is a pump that operates by receiving power from the input shaft of the transmission, etc., and is connected to the reserve tank 45 through a suction oil passage 46, and to the control valve 43 through a power steering pressure oil passage 47. ing.

The control valve 43 is a valve that is switched by steering the steering wheel 41, and is connected to the reserve tank 45 through a drain oil passage 48.

The power cylinder 44 is a cylinder that uses hydraulic pressure to power-assist the steering force to the steering linkage, and the control valve 43 is connected to an assist pressure oil passage 49.
．． 49'.

Note that when the control valve 43 is in the neutral steering position, the power steering pressure oil passage 47 is connected to the drain oil passage 48.
The power steering hydraulic pressure P corresponds to the steering force when the steering wheel 41 is switched to one side by the steering force applied to the steering wheel 41.
s is generated, and hydraulic oil by this power steering oil pressure Ps is supplied to the power cylinder 44 and also to the valve device 50 from the branch oil path 51.

The valve device 50 is a device that controls the input hydraulic pressure to the hydraulic pressure generating device 60, and includes a first solenoid valve 52, a second solenoid valve 53, a switching mode switch 54, and a solenoid operating circuit 55 in the embodiment.

The first solenoid valve 52 and the second solenoid valve 53 are structurally the same, and the boat 152a (153a
), 152b (153b), 152c (153c), and valve hole 152 (153).
The valve spool 252 (253) is provided to be movable in the axial direction at the valve spool 252 (253).
3) to the right in the drawing.
), a plunger 452 (453) that pushes the valve spool 252 (253) to the left in the drawing, and a plunger 45
2 (453), and a solenoid coil 552 (553) that applies electromagnetic force by energizing.

Note that the boats 152a and 153a are drain boats. 152b is connected to the branch oil passage 51. 152c and 153b are connected to the proportional pressure oil passage 56 and communicated with the first inlet cupo door 62a of the hydraulic pressure generator 60. The boat 153c is connected to the pressure boosting oil passage 57 and communicated with the second capo 862a of the hydraulic pressure generator 60.

The mode switch 54 is a switch that is installed inside the vehicle and is used to manually change the mode.The modes include LSD-OFF, which does not limit differential, LSD-ON, which limits normal differential, and high-level differential control. Obtaining the dynamic limit amount I
, 5D-UP, and 5D-UP.

The solenoid operating circuit 55 is a circuit that outputs an energizing or de-energizing signal to the solenoid coils 552, 553 of the first solenoid valve 52 and the second solenoid/bulb 53 in response to a switch signal from the switching motor switch 54, Switching motor suite, Chi54 is LSD building OF
At F, neither solenoid coil 552 or 553 is energized, and the mode switch 54 is set to L.
When SD is ON, one solenoid coil 552 is energized and the mode switch 54 is set to LSD.
- When in UP, both solenoid coils 552 and 553 are energized.

The oil pressure generator 60 converts the power steering oil pressure Ps inputted through the valve system fi50 into a clutch oil pressure P.
This device is equipped with a reserve tank 61 and a hydraulic pressure generating cylinder 62 having a brake mask cylinder structure.

The hydraulic pressure generating cylinder 62 is a power steering hydraulic pressure Ps.
This means has the function of generating a clutch hydraulic pressure Ps proportional to the power steering hydraulic pressure Ps at approximately the same pressure level as the pressure level, and the function of increasing the power steering hydraulic pressure Ps by expanding the pressure receiving area. With piston 362. Return spring 462, piston cups 562, 682, proportional pressure chamber 76
2. First manpower port 62a, pressure boosting chamber 862, second manpower port 862a, refueling port 962. pressure chamber 1062,
It is composed of an output hydraulic boat 1062a and a communication path 1162.

Next, the operation of the embodiment will be explained.

(a) When the LSD is OFF, do not use the differential limit when parking in a garage, etc., and change mode switch 5.
4 is set to the LSD-OFF position, no energization signal is output from the solenoid operating circuit 55 to either of the solenoid valves 52.53, and the valve spools 252, 253 of the solenoid valves 52.53 are turned off. , as shown in FIG. 4, is located on the right side of the drawing, and the power steering hydraulic pressure Ps is not supplied to the hydraulic pressure generating cylinder 62.

Therefore, the clutch hydraulic pressure P is output from the hydraulic pressure generating cylinder 62.
c does not occur, and the differential device 10 becomes a compensatory differential that does not have the ability to generate differential limiting torque, making it possible to smoothly park the vehicle in a garage, etc., which requires large-scale steering at low speeds.

(b) When the LSD is ON When driving in general, etc., when the mode switch 54 is set to the LSD-ON position, the solenoid operating circuit 55 energizes one of the first solenoid valves 52. The signal is output, and the valve spool 252 of the first solenoid pulp 52 is moved to the left position in the drawing by electromagnetic force.

By this movement of the valve spool 252,
2b and bow) 152c communicate with each other, branch oil passage 51 and proportional pressure oil passage 56 are connected, and power steering hydraulic pressure PS is supplied to first bow) 762a of oil pressure generating cylinder 62.

Therefore, in the hydraulic pressure generating cylinder 62, the stepped piston 362 is activated by the power steering hydraulic pressure Ps in the proportional pressure chamber 762 and the hydraulic pressure Fpt (=PsXA+) due to the pressure receiving area A1 (=output side piston cross section $AA3) of the stepped piston 362. Pressure chamber 10 can be moved to the right side of the drawing.
At 62, a hydraulic pressure proportional to the power steering hydraulic pressure Ps is generated, and this hydraulic pressure can be output as the clutch hydraulic pressure Pc from the output hydraulic pressure port 1062a, and the multi-disc friction clutch 11 is engaged by the output of the clutch hydraulic pressure Pc. .

The relationship between the power steering hydraulic pressure Ps and the lateral acceleration due to cornering is as shown in Fig. 5. As the lateral acceleration increases, the power steering hydraulic pressure Ps increases in proportion, so when cornering, the lateral acceleration image It is possible to obtain a differential limiting amount according to the

(c) When the LSD event is UP When the selector switch 54 is set to the LSD-UP position, such as when escaping from a muddy or sandy area, both solenoid valves 52.5 are output from the solenoid operating circuit 55.
An energization signal is output to valve 3, and both solenoid valves 5
2.53 valve spools 252, 253 are moved to the left position in the drawing by electromagnetic force.

By this movement of the valve spools 252 and 253, the ports 152b and 152c communicate with each other, and the ports 153b and 153c also communicate with each other, and the branch oil path 51
The proportional pressure oil passage 56 and the pressure increase oil passage 57 are connected to each other, and the power steering oil pressure Ps is supplied to the first port 762a and the second port 862a of the oil pressure generating cylinder 62.

Therefore, in the hydraulic pressure generating cylinder 62, the hydraulic pressure F P2 (= P s × A2) due to the power steering hydraulic pressure PS and the pressure receiving area A2 (>output side piston cross-sectional area A3)
is added, and the force for moving the stepped piston 362 to the right in the drawing is strengthened, so that a hydraulic pressure higher than the power steering hydraulic pressure Ps is generated in the pressure chamber 1062, and this hydraulic pressure is outputted from the output hydraulic port 1062a as the clutch hydraulic pressure Pc. The multi-disc friction clutch 11 is strongly engaged by the output of the clutch oil pressure Pc.

By strongly engaging the multi-disc friction clutch 11, a high differential limiting amount can be obtained, allowing the vehicle to escape from muddy areas and the like.

As described above, in the automobile differential limiting clutch device of the embodiment, the hydraulic pressure generating device 60 receives the power steering hydraulic pressure Ps from the power steering device 40 through the valve system 5i50, and adjusts the hydraulic pressure to be input. Since the device converts the hydraulic pressure into clutch oil pressure Pc, by increasing the pressure in this oil pressure generating device 60, it is possible to obtain a sufficiently high clutch oil pressure Pc even when the power steering oil pressure is low when the vehicle is not being steered. can.

In addition, since the power steering hydraulic pressure Ps is a hydraulic pressure that corresponds to the steering torque, by using this hydraulic pressure change as it is, it is possible to obtain a differential limit amount that corresponds to the lateral acceleration during cornering, which improves cornering stability. is ensured.

Furthermore, by providing the valve device 50 that operates based on the mode position of the mode switch 54, the degree of differential restriction can be varied depending on the driving state.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention may be modified without departing from the gist of the present invention. included.

For example, in the embodiment, a differential device was shown as an example of a power split device, but it can also be applied to a transfer device used as a drive force distribution device in a four-wheel drive vehicle, and the drive system clutch in this case is a differential device. A variable torque clutch is used to make the torque variable.

Further, in the embodiment, an example was shown in which the valve device is operated by a manually operated switching mode switch, but it is also possible to automatically switch the valve by using an input sensor and a control unit such as a microcomputer. good.

In addition, a slip sensor may be used as the input sensor, and a valve may be operated according to the detection of slip.Also, if you want to further increase the differential limit amount for sports driving, you can use a slip sensor at a certain vehicle speed or higher (or The valve may be actuated by the accelerator opening (or a combination thereof), or the valve may be actuated by the actuation of the ASCD switch (constant speed driving switch) in order to increase the differential restriction amount when driving straight at high speed. Alternatively, in order to reduce the tendency for understeer at the beginning of a turn, the differential restriction may be released by deactivating the valve until the brake is depressed and then the accelerator is depressed.

Further, in the embodiment, a device with a switching valve structure is shown as the valve device, but a device with a pressure regulating valve structure or the like that can perform stepless hydraulic control may also be used.

(Effects of the Invention) As explained above, in the vehicle drive system clutch device of the present invention, the power steering hydraulic pressure from the power steering device is not directly used, but is used as the input hydraulic pressure of the fluid pressure generating means. Since the means is used indirectly, high clutch pressure can be obtained by increasing the pressure in the fluid pressure generating means without being limited by the pressure level of the power steering oil pressure.

In addition, during steering, the power steering hydraulic pressure changes to a hydraulic pressure that corresponds to the steering torque, so by utilizing this hydraulic pressure change, it is possible to obtain clutch engagement pressure that corresponds to lateral acceleration during cornering, and by installing a valve device. By doing so, it is also possible to freely control the clutch engagement pressure.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of a claim showing a vehicle drive system clutch device of the present invention, FIG. 2 is a sectional view showing a differential device to which the differential limiting clutch device of an embodiment of the present invention is applied, and FIG. FIG. 4 is a diagram showing the differential limiting clutch device of the embodiment, and FIG. 5 is a characteristic diagram showing the relationship between power steering oil pressure and lateral acceleration. 1.2...Drive wheel 3...Power split device 4...Drive system clutch means 5...Fluid pressure generation means 6...Power steering device 7...Valve device Patent applicant Nissan Motor Co., Ltd. Co., Ltd.

Claims (1)

[Claims] 1) A power split device that distributes and transmits engine driving force to front and rear or left and right drive wheels, and a power split device that is provided between a drive input section and a drive output section of the power split device, and that is provided with an external fluid source. A drive system clutch device for a vehicle comprising a drive system clutch means that generates a clutch engagement force by pressure, and a fluid pressure generating means that is connected to the drive system clutch means and generates fluid pressure to the drive system clutch means. , wherein the fluid pressure generating means is a means for inputting power steering generated hydraulic pressure from a power steering device via a valve device and converting the input power steering generated hydraulic pressure into increased fluid pressure. Vehicle drive system clutch device.