JPS6170250A - Differential limiter - Google Patents

Abstract

PURPOSE:To prevent reverse steering during a turn by decreasing the tightening force of a friction clutch and suppressing the differential limiting action when the car lateral acceleration is a preset value or higher. CONSTITUTION:The preset value G0 of the lateral acceleration is stored in a hydraulic control means 31 in advance. The car lateral acceleration (g) based on a lateral acceleration signal (c) from a lateral acceleration sensor 32 and the preset value G0 are compared, and if the car lateral acceleration (g) exceeds the preset value G0, a hydraulic control signal (e) turning a solenoid valve 30 OFF is outputted. Then, the pressurized oil fed to a hydraulic port 19' is returned to a reservoir tank 27 to control so that no differential limiting action takes place, thereby reverse steering can be prevented during a turn.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a differential limiting device that controls clutch engagement force to a friction clutch according to predetermined conditions.

(Prior Art) As a conventional differential limiting device, one shown in FIG. 5, 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. 101' which are disposed facing each other inside a differential case 100 and are provided with left and right axle shafts, and the side gears 101. Binion mate gear 1 is disposed between LOI' and meshes with side gears 101, 101'.
02, a pressure ring 104, 104' which is disposed opposite to the outer periphery of the side gear 101, 101' and is cam-coupled to the end of the binion mate shaft 103, and the pressure ring 104. , 104' and the differential case 100, and the side gears 10i, ioi'
and friction clutches 105, 105' for frictionally engaging the differential case 100 and the differential case 100.

The friction clutches 105, 105' are comprised of friction discs 106, 106' fixed to the side gears 101, 101', and a differential case 10.
Frixibon plates 107, 107 fixed on the 0 side
108, 108' Dishes friction brake with disc spring structure that applies initial torque to the clutch
It was composed of.

Therefore, the friction clutch 105.105 in the conventional device
The clutch engagement force to ' is caused by the initial torque from the dished friction plates 108, 108' and the pressure rings 104, 10 pushed open by the cam action.
This is due to the pressing force from 4', and looking at the transfer ratio characteristics, as shown in FIG. 6, the characteristic line A is a combination of the initial torque portion a and the pressing force portion 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, when turning, if the lateral acceleration is low,
A drive torque is applied to the inner wheel to prevent it from turning, resulting in an understeer tendency, but as the lateral acceleration increases, as shown in Figure 7, the ground contact load on the inner wheel decreases and the drive torque on the outer wheel suddenly decreases. It starts to occur more often.

For this reason, the direction of the vehicle's yaw moment due to the differential limiting action reverses after a certain lateral acceleration, becomes the same direction as the yaw moment due to turning, and suddenly changes from an understeer tendency to an autosteer tendency. The problem is that it causes so-called ri/<-steering, exhibits turning performance as shown in the graph of the relationship between turning radius ratio and lateral acceleration in Figure 8, and is difficult to operate C± in unfamiliar dry/<- conditions. there were.

(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 lateral acceleration signal from the vehicle lateral acceleration detection means is input to the vehicle lateral acceleration detection means for detecting lateral acceleration acting on the vehicle and the fluid pressure generation means, and the vehicle lateral acceleration is set to a set value. In this case, a fluid pressure control means is provided that outputs a fluid pressure control signal that weakens the clutch engagement force of the friction clutch.

(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 by the fluid pressure control signal from the fluid pressure controlling means is controlled so that the vehicle lateral acceleration exceeds a set value. It decreases when

Due to this reduced fluid pressure, the clutch engagement force of the friction clutch is weakened, the differential limiting action is suppressed, and it is possible to avoid reverse steering when turning.

(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 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 with respect to the housing 1 by a tapered roller bearing 4.4'. Reference numeral 5 denotes a ring gear, which is fixed to the differential case 3. meshes with a vinyl 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. This side gear 8.8' has 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 rectangular grooves 12a, 12a' formed at opposing positions, and has a rectangular cross section 10a formed at the end of the pinion mate shaft 10. contact engagement.

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

Reference numeral 14.14' denotes a reaction plate, which is arranged in contact with the outer surface of the friction clutch 13.13'.

15.15' is a needle bearing, and the reaction plates 14, 14' and spacers 16.16
' is interposed between the friction clutch 13 and
．． One friction clutch 13 side receives the reaction force of the clutch engagement force of 13' from the rear axis.

Template 14. Needle bearing 15. Spacer 1
6. Butschrod 17. The other friction clutch 13' side is supported by the housing 1 via a reaction plate 14', 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 920 includes a motor 22 that drives the hydraulic pump 21, a pressure oil pipe 24 that supplies pressurized oil from the hydraulic pump 21 to the reserve tank 23, or the hydraulic port 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 solenoid is provided on the branch pipe 29 of the pressure oil vibrator 24 and switches between supplying pressurized oil to the hydraulic boat 19' side or returning it to the reserve tank 27 to lower the supply pressure. The valve 30 is configured to include a valve 30.

31 is a hydraulic control means as a fluid pressure control means,
When the lateral acceleration signal (C) from the lateral acceleration sensor 32 as a vehicle lateral acceleration detection means is input and the vehicle lateral acceleration g is equal to or higher than the set value 00, the friction clutch 13.13'
Hydraulic control signals (d), (e) to weaken the clutch engagement force of
This outputs the following.

In other words, the hydraulic pressure control means 31 of the embodiment stores the set value GO of the lateral acceleration in advance, and the vehicle lateral acceleration g based on the lateral acceleration signal (c) from the lateral acceleration sensor 32 and the set value GO When the vehicle lateral acceleration g exceeds the set value GO, a hydraulic control signal (e) that turns off the solenoid valve 30 is output, and the hydraulic pressure port 19'
The pressurized oil supplied to the pump is returned to the reserve tank 27, and control is performed so that the differential limiting action is not exerted.

Reference numeral 33 denotes a vehicle speed sensor as a vehicle speed detection means, which outputs a vehicle speed signal (f) to the hydraulic control means 31. The hydraulic control means 31 to which this vehicle speed signal (f) is inputted detects that the vehicle speed ■ is in the garage. Under the condition of extremely low speed (below the set vehicle speed vO), such as when the friction clutch 13.1
Hydraulic control signal (d) that reduces the clutch engagement force of 3'
.

(e) is output to the hydraulic pressure generator 20.

In other words, when the differential limiting action is exerted at extremely low speeds, the steering torque increases and the ratio of the difference in the rotation radius between the inner and outer wheels increases, causing tire stick-slip phenomena and friction clutches 13 and 13'. The differential limiting effect is suppressed to prevent chatter noise from occurring.

34 is a pressure sensor as a pressure detection means, which is installed in the pressure oil pipe 24,
0 to the hydraulic boat 19', a pressure signal (g) is output to the hydraulic pressure control means 31, and the actual hydraulic pressure P is the set hydraulic pressure P when the differential limiting action is exerted.
It is used as an input signal when the hydraulic pressure control means 31 compares whether it is larger or smaller than a.

Note that the control performed by the hydraulic control means 31 is based on the lateral acceleration signal (C) from the lateral acceleration sensor 32.

Vehicle speed signal (f) from vehicle speed sensor 33, pressure sensor 34
This is done by using the pressure signal (g) from the input signal as an input signal, and outputting the hydraulic control signals (d) and (e) to the motor 22 and the solenoid valve 30 according to the control logic diagram shown in FIG. 711J3.

Next, the operation of the embodiment will be explained.

(a) When the lateral acceleration g of the vehicle is below the set value Go If the lateral acceleration g of the vehicle is below the set value Go and the vehicle speed is not extremely low, pressurized oil is supplied from the hydraulic pressure generator 20; A clutch engagement force is applied to the friction clutches 13 and 13' to exert a differential limiting action.

The hydraulic control at this time is performed according to the control logic diagram shown in Fig. 3, and when the lateral acceleration g is less than the set value GO and the vehicle speed V is more than the set value Vo (very low vehicle speed), Solenoid valve 30 by circuit 35
is ONL, the return of hydraulic oil to the reservoir tank 27 is cut off, and when the vehicle speed ■ is higher than the set value Vo and the oil pressure P is less than the set pressure PO, the AND circuit 36 causes the motor 22 to turn ONL and the oil pressure Pressurized oil is supplied from the generator 20.

Therefore, when the lateral acceleration g of the vehicle is less than the set value Go, the steady circular turning performance exhibits weak understeer due to the differential limiting action, as shown in FIG. 4, and exhibits favorable turning performance.

(b) When the lateral acceleration g of the vehicle is greater than the set value Go When the lateral acceleration g of the vehicle is greater than the set value Go, that is, when making a sharp turn, etc., if the differential limiting action is left in effect, The differential limiting action is suppressed to induce so-called reverse steering, which is a sudden change from understeer tendency to oversteer tendency.

The hydraulic control at this time is also performed according to the control logic diagram shown in FIG. 3. Since the lateral acceleration g of the vehicle is greater than the set value Go, the solenoid valve 30 is turned OFF.
The pressurized oil in the hydraulic boat 19' is returned to the reserve tank 27, and the clutch engagement force of the friction clutches 13, 13' decreases at once.

Therefore, as shown in FIG. 4, when the lateral acceleration g of the vehicle is equal to or greater than the set value Go, the steady circular turning performance can continue to maintain the tendency of weak understeer due to the reduction of the differential limiting action.

(c) When the vehicle speed ■ is below the set value Vo When the vehicle speed ■ is below the set value Vo, the motor 22 and the solenoid valve 30 are turned OFF, and the differential limiting action is performed as in the case (b) above. Try not to let it show.

Therefore, at extremely low speeds, the steering torque must be increased and the tire stick-slip phenomenon.

J! ! , chatter noise from the friction latch 13, 13' can be prevented.

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 of the present invention, a control method is adopted in which the clutch engagement force is suddenly reduced when the vehicle lateral acceleration exceeds a set value. The control method may be the same or other control methods.In short, any control that does not cause reverse steering when the lateral acceleration is large is sufficient.

In addition, when exerting the differential limiting action, in the embodiment, a constant clutch engagement force is applied by the set pressure, but
The clutch engagement force may be variably controlled depending on the vehicle speed or the like.

Further, the mechanical device portion of the differential limiting device is not limited to the embodiment as long as it is a device that does not generate clutch engagement force through cam action or the like.

(Effects of the Invention) As explained above, according to the differential limiting device of the present invention, when the vehicle lateral acceleration is equal to or higher than a set value, the fluid pressure generating means has Since the vehicle is equipped with a fluid pressure control means that weakens the understeering, it is possible to maintain the steering characteristic during turning at a weak understeer characteristic.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a differential limiting device according to an embodiment of the present invention, FIG. 2 is a view seen from the direction of arrow Z in FIG. 1, FIG. 3 is a hydraulic control logic diagram in the embodiment device, and FIG. 4 5 is a diagram showing the relationship between turning radius ratio and lateral acceleration according to the example device. FIG. FIG. 8 is a diagram showing the relationship between turning radius ratio and lateral acceleration using a conventional device. 3...Differential case 8.8'...Side gear 13.13'...Friction clutch 18...Hydraulic piston (clutch engagement means) 20...
- Hydraulic pressure generator (R body pressure generation means) 31... Hydraulic pressure control means (fluid pressure control means) 32... Lateral acceleration sensor (vehicle lateral acceleration detection means) C... Lateral acceleration 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 for a vehicle that detects lateral acceleration acting on the vehicle in 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 lateral acceleration signal from the vehicle lateral acceleration detection means is input to the lateral acceleration detection means and the fluid pressure generation means, and fluid pressure is applied to weaken the clutch engagement force of the friction clutch when the vehicle lateral acceleration is equal to or higher than a set value. A differential limiting device comprising: fluid pressure control means that outputs a control signal.