JPH0557928B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a differential control device for a vehicle that controls the differential resistance force of a differential limiting mechanism in accordance with the driving condition of the vehicle.

(Prior art) Regarding a differential mechanism equipped with a conventional differential limiting mechanism, for example, "Nitsun Service Bulletin" (1982)
The one described in October, published by Nissan Motor Co., Ltd., pp. 69-71) is known.

This differential mechanism ensures smooth maneuverability by absorbing the difference in rotation between the left and right drive wheels when the vehicle turns, etc., and by generating effective friction torque in the differential mechanism. A differential limiting mechanism is provided in order to limit the differential operation of the wheels and make it easier for the wheels to escape, for example, even when one wheel gets stuck in mud or the like with low ground resistance and spins idly. This differential limiting mechanism consists of two sets of left and right multi-plate clutch mechanisms, each consisting of a friction plate fitted into the differential case of the differential mechanism and a friction disk fitted to the side gear. . Each clutch mechanism has a dish-shaped preload spring (date/friction plate).
A preload torque is applied to the clutch mechanism in advance by this biasing force. Further, the clutch mechanism includes a pressure ring that is divided into left and right halves and splined to be movable left and right inside the differential case. This pressure ring is equipped with a V-shaped groove on its split opposing surface, and this V-shaped groove
A shaped groove supports both ends of the shaft of the pinion mate gear. Therefore, as the differential case revolves, the pressure ring moves left and right due to the cam action between the shaft and the contact surface of the V-shaped groove, and a pressing force is applied to the clutch mechanism. This pressing force is applied to the clutch mechanism as a friction torque proportional to the input torque from the engine.

Therefore, the differential resistance force that limits the rotational difference between the left and right drive wheels is set by a combination of the proportional component by the pressure ring and the preload torque by the preload spring, and when the input torque is small and the proportional torque component is small, The structure is such that the preload torque is applied by the preload spring.

(Problem to be Solved by the Invention) However, in the above-mentioned differential limiting mechanism, the preload torque of the clutch mechanism is set in advance by the biasing force of the preload spring, and the proportional torque is applied to the V-shaped groove of the pressure ring. Due to the cam action of However, if the accelerator pedal travel distance is small, the input torque will be small and a differential differential between the left and right drive wheels will be allowed. Therefore, there has been a problem in that straight-line stability is extremely deteriorated when the vehicle is exposed to crosswinds while driving at high speeds.

(Objective of the Invention) Therefore, an object of the present invention is to solve the above-mentioned problems by actively applying a differential resistance force of a differential limiting mechanism when a crosswind is encountered while driving at high speed. It is something.

(Means for Solving Problems) The differential control device of the present invention, as shown in the overall configuration diagram of FIG. Differential mechanism 1 that distributes and transmits information to both left and right drive wheels.
and a differential limiting mechanism 1 that limits the amount of differential movement between the two output sections by applying a differential resistance force using a clutch mechanism provided between the input section and the output section of the differential mechanism 1.
2, and further detects the vehicle speed and outputs a detection signal corresponding to the magnitude of the vehicle speed.
, a crosswind detection means 42 that detects a crosswind and outputs a detection signal corresponding to the magnitude of the crosswind, a control means 48 that outputs a control signal based on the detection signals from both of these detection means 41 and 42, and a control The structure includes a hydraulic drive means 18 that increases the friction force of the clutch mechanism of the differential control mechanism 12 according to the magnitude of the signal, and limits the differential between the left and right drive wheels when a crosswind is encountered while driving at high speed. It is something to do.

(Example) An example of the present invention will be described below based on the drawings.

As shown in FIGS. 2 to 4, the vehicle differential control device of this embodiment includes a differential mechanism 1 that distributes the power input from the engine to two left and right output sections where a differential is allowed. , a differential limiting mechanism 12 that limits the differential amount between the left and right output sections, and a detection means group 40 that detects the magnitude of the vehicle speed and the magnitude of the crosswind.
, a control circuit (control means) 48 that outputs a control signal corresponding to the detection signal from each detection means, and a hydraulic drive means that operates to increase the differential resistance force of the differential limiting mechanism 12 based on the control signal. 18.

As shown in FIG. 2, the differential mechanism 1 has an input shaft (input section) 2 connected to an output shaft of an engine via a transmission and a propeller shaft. A drive pinion 3 is also provided at the end of the input shaft 2.
The differential case 4 is fitted with a driven gear 5 fixed to the outer periphery of the differential case 4 so as to mesh with the drive pinion 3, and the differential case 4 rotates as the input shaft 2 rotates.
A pinion mate shaft 6 is disposed within the differential case 4 in a direction perpendicular to the axis around which the differential case 4 rotates.
A pair of pinion mate gears 7 (one not shown) is rotatably supported at both ends of the pinion mate shaft 6. Also, inside the differential case 4, a pair of side gears 8 mesh with both pinion mate gears 7 and coaxially face each other, and drive shafts (output shafts) rotatably supported by a housing 9. part) 10 so as to be integrally rotatable.

Further, the differential limiting mechanism 12 includes a pressure ring 13 that covers the pinion mate gear 7 and the side gear 8 within the differential case 4. This pressure ring 13 is divided into left and right parts, and a V-shaped groove is provided at each opposing end.
Both ends of a pinion mate shaft 6, which is fitted into this groove and has a substantially square cross section, are supported. Further, a protrusion formed in the axial direction on the outer periphery of the pressure ring 13 is slidably fitted into a groove formed inside the differential case 4, so that the pressure ring 13 and the differential case 4 are connected to each other. and can slide relative to each other in the axial direction (horizontal direction in the figure). Further, inside the differential case 4, there are provided two sets of left and right clutch mechanisms 14, which are made up of multiple plates and connect the differential case 4 and the shaft portions 8a of the left and right side gears 8.

Each clutch mechanism 14 consists of friction disks 15 and friction plates 16 that are alternately arranged in the left-right direction (in the axial direction of the drive shaft 10) between the pressure ring 13 and the differential case 4. It is configured. A projection on the inner circumference of the friction disk 15 is slidably fitted into a groove on the outer circumference of the shaft portion 8a of the side gear 8, so that the friction disk 15 can rotate integrally with the side gear 8. On the other hand, the friction plate 16 has a protrusion on its outer periphery that is slidably fitted into a groove on the inner periphery of the differential case 4 . It has a structure that allows it to be fitted into the differential case 4 and rotate integrally with the differential case 4.

As shown in FIG. 2, the hydraulic drive means 18 includes a hydraulic actuator 19 that applies a pressing force to the clutch mechanism 14;
The actuator 19 is connected to each of the left and right clutch mechanisms 14.

The hydraulic actuator 19 includes a reaction plate 20, a thrust bearing 21, and a spacer 2.
2, a push rod 23 and a piston 24. The reaction plate 20 is formed into an annular disc and is disposed outside both ends of the differential case 4, and has a plurality of protrusions 20a protruding toward the differential case 4. It loosely passes through each hole provided in the seal case 4 and comes into contact with the friction plate 16. Each reaction plate 20 is supported by a spacer 22 via a thrust bearing 21 on its outer surface. Each of these spacers 22 is formed into an annular shape and is accommodated in an annular groove 25 provided in a housing 9 that accommodates the differential case 4 so as to be slidable in the axial direction. Also, housing 9
, a plurality of insertion holes 26 are formed in the circumferential direction of the drive shaft 10, one end of which opens in the annular groove 25 on one side shown on the left side of the figure, and an annular groove 27 with the other end of these insertion holes 26 open. is formed. An annular piston 24 provided with a seal ring is inserted into the annular groove 27, and a push rod 23 connecting the piston 24 and the spacer 22 is loosely inserted into the insertion hole 26. Further, the housing 9 is provided with a hydraulic port 28 through which hydraulic oil for driving the piston 24 is introduced. Therefore, when hydraulic pressure is supplied to the hydraulic port 28 of the hydraulic actuator 19, the piston 24 moves, and the push rod 23, spacer 22, thrust bearing 21, and reaction plate 20 move accordingly.
A pressing force is applied to the friction plate 16 of the clutch mechanism 14 on the left side in FIG.
In addition, in the other clutch mechanism 14 shown on the right side of the figure, a pressing force is applied to the spacer 22, the thrust bearing 21, and the reaction plate 20 due to the reaction force of the housing 9 accompanying the movement of the push rod 23 driven by the piston 24. Granted.

On the other hand, the hydraulic circuit 29, as shown in FIG.
A hydraulic pump 31 driven by a motor 30 is connected from a reservoir tank 32 to the hydraulic port 28 of the hydraulic actuator 19 via a check valve 33 and a relief valve 34, and the output side of the check valve 33 is connected to the hydraulic port 28 of the hydraulic actuator 19 through a relief valve 35. It is connected to the reservoir tank 32 via a solenoid valve 36, and a pressure switch 37 is disposed on the output side of the check valve 33. The solenoid coils of the motor 30 and the solenoid valve 6 are connected to a control circuit (control means) 48, which will be described later, and the motor 30 and the solenoid valve 6 are energized and controlled by a control signal from the control circuit 48. The hydraulic pump 31 operates as the motor 30 is driven,
Pressure oil is supplied from the reservoir tank 32 to the hydraulic port 28 via a check valve 33 and a check valve 34. On the other hand, the solenoid valve 36
When the control signal from 8 is input to the solenoid coil, the flow path connecting the hydraulic port 28 and the reservoir tank 32 is closed to maintain the hydraulic pressure of the hydraulic port 28 at a high pressure, while the control signal is input to the solenoid coil. If not, the flow path is made conductive to reduce the oil pressure in the hydraulic port 28. The pressure switch 37 sends a signal to the control circuit 48 when the hydraulic pressure supplied to the hydraulic port 28 is less than the set value.
The motor 30 is driven by the control circuit 48 . Further, the relief valve 35 is configured to operate when the hydraulic pressure supplied to the hydraulic port 28 significantly rises above a set value to maintain an appropriate set hydraulic pressure.

As shown in FIG. 4, the detection means group 40 includes:
Vehicle speed detection means 4 that detects vehicle speed and outputs an analog electrical signal (detection signal) corresponding to the magnitude of the vehicle speed.
1, a crosswind detection means 42 that outputs an analog electric signal (detection signal) corresponding to the magnitude of the crosswind received from the side of the vehicle body, and furthermore, in this embodiment, a digital electric signal is output only when the steering angle is within a set range. It is composed of a steering angle detection means 43 that outputs a signal, and relays 44 and 45 that operate to be in a non-conducting state in response to an electric signal from the steering angle detection means 43. That is, the vehicle speed detection means 41 is connected to a control circuit (control means) 48 via a relay 44, the crosswind detection means 42 is connected to a control circuit (control means) 48, which will be described later, through a relay 45, and the steering angle detection means 43 is connected to each excitation of both relays 44 and 45. It is connected to coils 44a and 45a. The vehicle speed detection means 41 is constituted by, for example, a vehicle speed sensor that detects the vehicle speed by analogously detecting changes in the magnetic flux of a magnet rotating together with the speedometer cable using a built-in coil. The cross wind detection means 42 is constituted by, for example, a wind pressure sensor consisting of a thermistor and its detection circuit, which change the resistance in accordance with the amount of cross wind received on the side of the vehicle body. Further, the steering angle detection means 43 includes, for example, a displacement sensor consisting of a magnet that rotates together with the steering shaft and a magnetic resistance element that changes magnetic resistance by the rotation of the magnet, and a detection value of this displacement sensor that corresponds to a set value. It is comprised of a comparison circuit etc. that sends out a digital electric signal when the voltage exceeds the threshold, and when this output signal is input to the excitation coils 44a, 45a, the relays 44, 45 become non-conductive.

The control circuit (control means) 48 is configured to convert the analog electrical signals from the vehicle speed detection means 41 and the crosswind detection means 42 into pulse width modulation signals, and to control the duty of the hydraulic drive means 18 based on this signal. , for example, is composed of a microcomputer. That is, the control circuit 48 includes a comparison signal generation circuit 49 that outputs a comparison signal based on both analog electrical signals inputted from the vehicle speed detection means 41 and the crosswind detection means 42, and a sawtooth wave generation circuit 49 that outputs a sawtooth wave signal. The signal generation circuit 50 compares the sawtooth wave signal with the comparison signal and outputs a pulse signal (control signal) to the solenoid valve 36 of the hydraulic circuit 29.
The comparator circuit 51 outputs an output signal to the comparator circuit 51.
The comparison signal generation circuit 49 also includes a reference signal generation circuit 52 that generates a preset reference signal for preload torque, and a vehicle speed detection means 4 that uses this reference signal.
1 and the crosswind detection means 42. For example, in the comparator circuit 51, when the sawtooth wave signal Et and the comparison signal Ei are input as shown in FIG. 5a, the comparison signal Ei is changed to the pulse signal P shown in FIG. is converted to This pulse signal P is converted into a detection signal input from the vehicle speed detection means 41 and the crosswind detection means 42, that is, a duty ratio according to the vehicle speed and the magnitude of the crosswind.
Therefore, when the steering angle is within the set range, a differential resistance force is applied to the differential limiting mechanism 12 by the pulse signal obtained by converting both the detection signal and the reference signal, while the steering angle is within the set range. If it exceeds the reference signal, the relays 44 and 45 become non-conductive, and the detection signals from the vehicle speed detection means 41 and the crosswind detection means 42 are not input to the control circuit 48. The structure is such that only preload torque is applied.

Next, the effect will be explained.

First, when the steering angle is within the set range, for example, when making a gentle turn, the steering angle detection means 43
From the excitation coil 44a of each relay 44 and 45,
Since no electrical signal is sent to 45a, each relay 44, 45 is in a conductive state. In this state, an analog electrical signal at a level corresponding to the vehicle speed is sent from the vehicle speed detection means 41 through the relay 44, and an analog electrical signal corresponding to the magnitude of the crosswind is sent from the crosswind detection means 42 through the relay 45 to the control circuit 48. It is input to the adding circuit 53. In the addition circuit 53, both the analog electric signals corresponding to the vehicle speed and the magnitude of the crosswind are added to the reference signal from the reference signal generation circuit 52, and a comparison signal Ei
is sent. This comparison signal Ei is converted into a pulse signal P by the sawtooth wave signal Et from the sawtooth wave signal generation circuit 50 in the comparison circuit 51, and is outputted to the solenoid coil of the solenoid valve 36 as a control signal. Therefore, in the hydraulic circuit 29, the solenoid valve 36 opens and closes based on the pulse signal P, and the hydraulic pressure in the hydraulic port 28 of the hydraulic actuator 19 is duty-controlled. Accordingly, a pressing force is applied to the friction plate 16 of the clutch mechanism 14 via the piston 24, push rod 23, spacer 22, thrust bearing 21, and reaction plate 20 of the hydraulic actuator 19. That is, a pressing force corresponding to the pulse signal P is applied to the clutch mechanism 14, and a differential resistance force is applied to the differential control mechanism 12. This differential resistance force increases as the vehicle speed and crosswind increase, so when crosswinds occur especially when driving at high speeds, the differential of the differential mechanism 1 will surely limit the force regardless of the accelerator pedal depression operation. be done. Therefore, even if the vehicle is hit by a crosswind during high-speed driving with a small accelerator pedal depression, it is possible to maintain stable straight-line performance.

Next, when the steering angle exceeds the set range, an electric signal is sent from the steering angle detection means 43 to the excitation coils 44a and 45a of each relay 44 and 45, and each relay 44 and 45 becomes non-conductive. Analog electrical signals from the vehicle speed detection means 41 and the crosswind detection means 42 are not input to the addition circuit 53 of the control circuit 48. Therefore, the comparison circuit 51 of the control circuit 48 outputs a pulse signal P with a small duty ratio obtained by converting only the reference signal, thereby applying only preload torque to the differential limiting mechanism 12. Therefore, when the steering angle becomes larger than the set range, that is, when making a sharp turn, the pressing force of the clutch mechanism 14 is weakened, regardless of high speed running or the size of the crosswind, and the difference in the differential mechanism 1 is reduced. Since the vehicle is allowed to move, it is possible to turn without causing tire slip or understeer, and appropriate steering performance can be ensured.

In the above embodiment, the steering angle detection means 43 is used to detect the detection signals input to the control circuit from the vehicle speed detection means 41 and the crosswind detection means 42.
Although the configuration is such that the cutoff occurs when the steering angle becomes large, the configuration may be configured without using the steering angle detection means 43. Even in this case, since at least the vehicle speed decreases when making a sharp turn, it is possible to obtain substantially the same effect as in the above embodiment.

(Effects of the Invention) As described above, according to the present invention, by controlling the differential resistance of the differential limiting mechanism in accordance with the vehicle speed and the magnitude of the crosswind, the accelerator pedal can be pressed at high speeds with a small amount of travel. Even if there is a crosswind while driving,
Since the differential movement of the differential mechanism is limited, straight-line stability can be improved, while operation is allowed during sharp turns, so appropriate steering performance can be ensured.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of the differential control device of the present invention,
Figures 2 to 5 are diagrams showing one embodiment of the present invention, with Figure 2 being a longitudinal sectional view showing the differential mechanism, differential limiting mechanism, and hydraulic drive means, and Figure 3 showing the hydraulic circuit. FIG. 4 is a schematic diagram showing the control means, and FIGS. 5a and 5b are waveform diagrams showing a comparison signal, a sawtooth wave signal, and a pulse signal, respectively. 1...Differential mechanism, 2...Input section (input shaft), 1
0... Output section (drive shaft), 12... Differential limiting mechanism,
18...Hydraulic drive means, 41...Vehicle speed detection means,
42... Cross wind detection means, 48... Control means.

Claims (1)

[Claims] 1 A differential mechanism that distributes and transmits the engine power input from the input section to the left and right drive wheels via two output sections that allow differential, and a differential amount between the input section and the output section. In a differential control device for a vehicle equipped with a differential limiting mechanism, a vehicle speed detecting means for detecting vehicle speed, a crosswind detecting means for detecting a crosswind acting on the vehicle body, and a combination of the vehicle speed detecting means and the crosswind detecting means. A vehicle comprising: a control means for outputting a control signal corresponding to a detection signal; and a hydraulic drive means for controlling the differential resistance of the differential limiting mechanism based on the control signal from the control means. Differential control device.