JPS6167629A - Differential-gear restricting apparatus - Google Patents

Abstract

PURPOSE:To obtain the optimum transfer ratio characteristic in accordance with car speed by applying the initial torque which continuously varies according to the car speed onto friction clutches installed between a differential gear case and the side gears in the differential gear case. CONSTITUTION:As for a differential-gear mechanism, the side gears 8 and 8' in which the right and left driving shafts 9 and 9' are spline-connected are arranged oppositely in a differential gear case 3 rotatably supported through bearings 4 and 4' onto a housing 1 fixed onto a chassis side. Pressure rings 12 and 12' are arranged oppositely onto the outer peripheral part of these side gears 8 and 8', and multiple-disc type friction clutches 13 and 13' are installed between the rings 12 and 12' and the differential gear case 3, and is engaged and disengaged by a hydrualic piston 18. In this case, the hydraulic pressure which is continuously varied according to the car speed is introduced into a pressurized-oil chamber 19 on one side of a hydraulic piston 18, so that a high pressure is generated, when the car speed increases, according to the output of a car-speed detecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention controls the engagement force of a friction clutch according to predetermined conditions, thereby improving the active transfer ratio (high driving force side torque/low driving force side torque). The present invention relates to a differential limiting device that can perform control.

(Prior Art) As a conventional differential limiting device, one shown in FIG. 8, for example, is known. "Nissan Skyline Service Bulletin No. 446 rSK-2", October 9, 1982
(Published by Nissan Motor Co., Ltd.) This conventional device includes a pair of side gears 101.degree. It is arranged between lO1' and side gear 1
Binion mate gear 10 meshing with 01, 101'
The pinion mate shaft LO3 provided with the pinion mate shaft LO3 and the side gear 101.
Pressure rings 104, 104' are cam-coupled with the ends of the pinion mate shirts (pinion mate shirts) 103, and are disposed between the pressure IJ links l04, l04' and the differential case lOO, and the side gears 1°i
, toi' and a differential case 100 through friction.

Incidentally, the friction clutches 105, 105' include friction discs 106, 106' fixed to the side gears 101, 101', and a differential case 10.
Friction plates 107, 107 fixed on the 0 side
', dished friction plates 108, 108 with disc spring structure that provide initial torque to the clutch
It was composed of.

Therefore, the friction clutch 105.105 in the conventional device
' The clutch engagement force is generated by the initial torque from the dished friction plates 108, 108' and the pressure rings 104, 1 pushed open by the cam action.
This is due to the pressing force from 04', and looking at the transfer ratio characteristics, as shown in FIG. 9, the characteristic line A is a combination of the initial torque a and the pressing force due to the cam action.

(Problems to be Solved by the Invention) However, in such a conventional differential limiting device, the dished friction plates 108, 108'
Since the initial torque is fixed and the transfer ratio characteristics are also uniquely determined, increasing the initial torque with priority given to high-speed driving improves high-speed straight-line performance, but when turning at low speeds There were problems such as stick-slip phenomenon occurring between the rear wheels and the road surface, loud stick-slip noise occurring at the friction clutches 105 and 105', and heavy steering force making it difficult to turn. However, if the initial torque is lowered with priority given to low-speed driving, there is a problem in that high-speed straight-line performance deteriorates, contrary to the case where the initial torque is increased.

Therefore, in practice, the initial torque setting is halfway done without prioritizing either high-speed or low-speed running.

(Means for Solving the Problems) That is, the present invention was made with the purpose of solving the above-mentioned problems, and in order to achieve this purpose, in the present invention, a A friction clutch interposed in the friction clutch, a clutch engagement means provided on the friction clutch for applying a clutch engagement force by external fluid pressure, and a fluid pressure generation means connected to the clutch engagement means. In the differential limiting device, a vehicle speed signal from the vehicle speed detection means is input to the vehicle speed detection means for detecting the vehicle speed and the fluid pressure generation means, and as the vehicle speed increases, the pressure increases, and conversely, as the vehicle speed decreases, the pressure decreases. A fluid pressure control means is provided to output a fluid pressure control signal for continuously changing fluid pressure in accordance with vehicle speed.

(Function) Therefore, in the differential limiting device of the present invention, the fluid pressure supplied from the fluid pressure generating means to the clutch engaging means changes according to the vehicle speed in accordance with the fluid pressure control signal from the fluid pressure controlling means.

Due to this changing fluid pressure, high initial torque is applied to the friction clutch during high-speed driving.

When running at low speeds, a low initial torque is applied, and since the magnitude of the initial torque changes continuously depending on the vehicle speed, it is possible to obtain an optimal transfer ratio characteristic depending on the vehicle speed.

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

In describing this embodiment, a differential limiting device for an automobile will be taken as an example.

First, the configuration of the first embodiment shown in FIGS. 1 and 2 will be explained.

1 is a housing, and this housing 1 is supported by a stud port 2 on the vehicle body side.

Reference numeral 3 denotes a differential case, which is rotatably supported by a tapered roller bearing 4.4' with respect to the housing l.

A ring gear 5 is fixed to the differential case 3. The ring gear 5 meshes with a pinion gear 7 provided on the propeller shaft 6, and the rotational driving force from the propeller shaft 6 is transmitted to the differential case 3. .

Reference numeral 8.8' denotes a side gear, which is disposed facing inside the differential case 3. The side gears 8, 8' include a left drive shaft 9 and a right drive shaft 9'.
are provided by spline connection.

A pinion mate shaft 10 is disposed between the side gears 8 and 8', and a pinion mate gear 11 that meshes with the side gears 8 and 8' is supported on the pinion mate shaft 10.

Reference numeral 12.12' denotes a pressure ring, which is disposed opposite to the outer periphery of the side gears 8, 8'.This pressure ring 12.12' is fixed to the differential case 3 in the rotational direction, and It is provided so that it can be slid in the direction.

As shown in FIG. 2, this pressure ring 12, 12' has V-shaped grooves 12a, 12a' formed at opposing positions, and a V-shaped cam portion formed at the end of the pinion mate shaft IO. 10a.

Reference numeral 13.13' denotes a friction clutch, which is interposed between the pressure ring 12.12' and the differential case 3.
' is a multi-plate clutch structure, and the friction plate fixed to the differential case 3) 13a, 13a
' and friction discs 13b, 13b' fixed to the side gears 8, 8'.

14.14' beam action plate, which is arranged in contact with the outer surface of the friction clutches 13, 13'.

15.15' is a needle bearing, which includes the reaction plate 14.14' and spacer 16.16.
', which is interposed between the friction clutch 13.
One friction clutch 13 side receives the reaction force of the clutch engagement force of 13' through the rear axle can plate 14. Needle bearing 15. Spacer 16. Bush Rod 17. The other friction clutch 13' side is supported by the housing l via the hydraulic piston 18, and the reaction plate 14'
, is supported by the housing 1 via a needle bearing 15' and a spacer 16'.

Reference numeral 18 denotes a hydraulic piston as a clutch fastening means, which is disposed in the housing l so as to be able to slide in the axial direction.A bushing rod 17 is provided on one end surface of the hydraulic piston 18, and a bushing rod 17 is provided on the other end surface. A pressure oil chamber 19 and a hydraulic port 19' are provided.

20 is a hydraulic pressure generating device as a fluid pressure generating means,
It supplies hydraulic pressure to the hydraulic piston 18,
This hydraulic pressure generator 20 includes a motor 22 that drives a hydraulic pump 21, a pressure oil pipe 24 that supplies pressurized oil by the hydraulic pump 21 from a reserve tank 23 to a hydraulic boat 19', and When the pressure oil flowing through the provided check valve 25 and the pressure oil pipe 24 exceeds a predetermined pressure, it passes through the relief pipe 26 to the reserve tank 2.
A relief valve 28 is provided in the branch pipe 29 of the pressure m pipe 24, and a drain is provided to switch between supplying pressurized oil to the hydraulic port 19' side or returning it to the reserve tank 27 to lower the supply pressure. The configuration includes a noid valve 30.

31 is a hydraulic control means as a fluid pressure control means,
A vehicle speed signal (
c), and as the vehicle speed increases, the pressure increases.
, a hydraulic control signal for continuously changing the fluid pressure according to the vehicle speed so that the pressure decreases as the vehicle speed decreases.
d) and (e) are output.

Note that this hydraulic control means 31 includes, as shown in FIG.
The relationship characteristics between vehicle speed and oil pressure are stored as data, and a hydraulic pressure level is calculated or selected according to the vehicle speed signal (C) from the vehicle speed sensor 32, and a hydraulic pressure control signal (d) according to this target oil pressure level, (e) is outputted to the motor 22 and the solenoid valve 30.

The actual oil pressure level generated by the oil pressure generator 2o is obtained by inputting the pressure signal (f) from the pressure sensor 33, and the actual oil pressure level based on this pressure signal (f) matches the target oil pressure level. controlled to do so.

Here, as a specific example of hydraulic control, the hydraulic control signal (d
) to rotate the motor 22 at a constant speed, control the duty ratio of the solenoid valve 3o by turning it 0N-OFF, and keep the solenoid valve 30 in the ON state (the flow to the reserve tank 27 is carted). It is possible to control the oil pressure level by increasing the length of the motor 2 to increase the oil pressure level, and conversely to lower the oil pressure level by making the OFF state longer.
2, a variable speed motor is used, the motor rotation speed is set according to the vehicle speed by the hydraulic control signal (d), and the solenoid valve 3
This is done by a control method such as using 0 as an auxiliary.

Next, the operation of the first embodiment will be explained.

(b) When the vehicle speed is low.

When the vehicle speed is low, the vehicle speed sensor 32 outputs a vehicle speed signal (C) corresponding to the speed to the hydraulic control means 31.

The hydraulic pressure control means 31 generates hydraulic control signals (d) and (e) for generating hydraulic pressure according to the vehicle speed signal (C).
is output to the hydraulic pressure generator 20, which supplies low pressure pressurized oil to the hydraulic boat 19'.

This pressurized oil moves the hydraulic piston 18 to the right in FIG. Apply clutch engagement force (initial torque). Note that a clutch engagement force is applied to the friction clutch 13' by a reaction force.

In addition, the pressure ring 12.12' that rotates together with the differential case 3 is a pinion mate shirt).
It is pushed open left and right by the cam action with 10, and applies a clutch engagement force to the friction clutch 13, 13'.

Therefore, when driving at low speeds, the characteristics shown in the transfer ratio characteristic diagram B in Figure 4 are exhibited, and the differential control effect is small, causing stick-slip phenomena and friction between the rear wheels and the road surface during low-speed turns. No stick-slip noise occurs in the clutches 13, 13', and the steering force does not become heavy.

(b) When the vehicle speed is high - When the vehicle speed is high, the same effect as described above occurs, but
Since the pressurized oil supplied from the hydraulic pressure generating device 20 has a high pressure, the initial torque to the friction clutch 13, 13' becomes large, and the transfer ratio characteristic is shown in the transfer ratio characteristic diagram C in Fig. 4. As a result, the differential limiting effect increases.

Therefore, as shown in Fig. 5, even if a yaw moment M in the turning direction occurs during high-speed driving, a moment M' in the opposite direction to the yaw moment M occurs due to the limited differential movement between the left and right wheels. However, by exhibiting a tendency to understeer during high-speed turns, high-speed straight-line performance is improved.

Note that the operation has been explained for when the vehicle speed is high and when the vehicle speed is low, but even at vehicle speeds between these times, as shown in FIG. 4, the oil pressure changes depending on the vehicle speed, and the friction clutch 13
．． Since the initial torque to 13' changes, the transfer ratio characteristic shows a transfer ratio characteristic that changes according to the vehicle speed within the range shown in Fig. 4, and a suitable differential limiting effect according to the vehicle speed. is obtained.

Next, the second embodiment shown in FIG. 6 and WS7 will be explained.

This embodiment includes a pinion mate shirt (pinion mate shirt) 10 whose end has a square cross section, and a hexagonal f+W that engages with this square cross section fob.
Pressure ring 1 with 12 b, 12 b'
2.12', as in the first embodiment,
No clutch engagement force is generated by the cam action on the friction clutches 13, 13', and the differential limiting action is obtained entirely by the clutch engagement force from the hydraulic piston 18.

Note that the other configurations are the same as those in the first embodiment, so explanations will be omitted.

Therefore, the transfer ratio characteristic in the second embodiment is as shown in the characteristic diagram shown in FIG. 5, and shows a characteristic that changes within region E depending on the vehicle speed.

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, the clutch engagement means and the hydraulic pressure generating means are not limited to those having the structure of the embodiment, but means having other structures may be used, or means using fluid other than hydraulic pressure may be used.

(Effects of the Invention) As explained above, according to the differential limiting device of the present invention, the fluid pressure generating means is provided with a fluid pressure control means that continuously changes the fluid pressure according to the vehicle speed. Therefore, it is possible to obtain suitable transfer ratio characteristics depending on the vehicle speed.

[Brief explanation of drawings]

1 is a diagram showing a differential limiting device according to a first embodiment of the present invention, FIG. 2 is a view seen from the direction of arrow Z in FIG. 1, and FIG. 3 is a diagram showing a hydraulic control means of the device according to the first embodiment. A memorized vehicle speed-hydraulic relationship diagram, FIG. 4 is a transfer ratio characteristic diagram in the device of the first embodiment, FIG. 5 is a plan view showing a car equipped with the device of the first embodiment, and FIG. A diagram showing the binion mate shaft and pressure ring of the second embodiment device of the present invention, FIG. 7 is a transfer ratio characteristic diagram in the second embodiment device, and FIG. 8 is a sectional view showing a conventional differential limiting device. FIG. 9 is a transfer ratio characteristic diagram of a conventional device. 3...Differential case 8.8'...Side gear 13.13'...Friction clutch 18...Hydraulic piston (clutch engagement means) 20...
・Hydraulic pressure generator (fluid pressure generating means) 31...Hydraulic pressure control means (fluid pressure control means) 32...Vehicle speed sensor (vehicle speed detection means) C...Vehicle speed signal

Claims (1)

[Claims] 1) A friction clutch interposed between the differential case and the side gear, and a friction clutch provided in the friction clutch,
A differential limiting device comprising a clutch engaging means for applying a clutch engaging force by external fluid pressure, and a fluid pressure generating means connected to the clutch engaging means, a vehicle speed detecting means for detecting vehicle speed; The vehicle speed signal from the vehicle speed detection means is inputted to the fluid pressure generating means, and the fluid pressure is continuously changed according to the vehicle speed so that the pressure becomes higher as the vehicle speed becomes higher and conversely becomes lower as the vehicle speed becomes lower. A differential limiting device comprising: a fluid pressure control means for outputting a fluid pressure control signal for controlling the differential.