JPH063698Y2 - Differential controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a differential control device, and more specifically, to a differential control device that is installed in a vehicle and that drives left and right wheels. The present invention relates to a device for controlling a differential.

(Prior Art) The acceleration state of the vehicle is detected by, for example, an accelerator, and when the accelerator is depressed, the vehicle is in an acceleration state.
Calculate the correction value according to the stepping amount or its differential value,
There has been proposed a differential limiting device that limits a differential by a value obtained by adding a correction value to a reference value (Japanese Patent Laid-Open No. 61-102321).

In the control device according to the above-mentioned proposal, the reference value is constant, and the correction value increases in proportion to the accelerator pedal depression amount.Therefore, the differential limiting amount increases as the accelerator pedal depression amount increases, and the difference becomes larger. The motion restriction will be strengthened.

(Problems to be Solved by the Invention) When a vehicle equipped with the differential control device tries to change the driving lane, the differential restriction becomes strong when the accelerator is depressed, so the understeer characteristic is added to the vehicle. It becomes possible to equate with, and the lane can be changed smoothly. However, if you do not step on the accelerator, the differential limitation does not work, so the vehicle behavior similar to that in which yaw mont in the turning direction occurs, especially at high speed,
So-called entanglement may occur, making it difficult to change lanes.

It is possible to set the reference value to a high value so that the lane can be changed smoothly when the accelerator is not depressed, but this makes the differential limitation too effective when the accelerator is depressed. On the contrary, the smooth lane change is lost.

If the absolute amount of the correction value is reduced and the difference in the differential limiting amount between when the accelerator is depressed and when the accelerator is not depressed is reduced, the occurrence of the above situation can be prevented, but the driver's operation of the accelerator pedal will make the muddy. To escape from the vehicle, power controllability by the accelerator at the time of turning, that is, when the driving force of the rear wheels is increased, the lateral force of the rear wheels decreases. It is difficult to secure the ease of control when controlling by accelerator operation due to the lack of the limited differential amount.

The purpose of the present invention is to ensure smoothness when changing lanes by changing the reference value and the correction value according to the running condition of the vehicle, while improving the ability to escape from muddy and power controllability. It is to provide a differential control device that can perform.

(Means for Solving the Problem) The present invention is a device for controlling the differential of a differential device having a differential limiting mechanism, which is a device for detecting a vehicle speed, a device for detecting a steering angle, and an accelerator. The controller includes means for detecting the amount of depression, a controller to which a signal from each of the means is input, and means for operating the differential limiting mechanism, which is controlled by a signal from the controller, and the controller is configured to control the vehicle speed and the steering angle Based on the standard values that increase at low and high vehicle speeds, decrease at medium vehicle speeds, decrease when the steering angle is large, and increase when the steering angle is small. It is a correction value based on the angle and the amount of accelerator depression, which decreases at low and high vehicle speeds, increases at medium vehicle speeds, and increases when the steering angle is large and decreases when the steering angle is small. A correction value determined by the product of the correction index determined as described above and the accelerator depression amount is obtained, and a signal corresponding to the value obtained by adding the correction value to the reference value is output to the operating means.

(Operation and effect) When the vehicle travels, on the other hand, the steering angle and the vehicle speed are detected,
On the other hand, the accelerator depression amount is detected. The reference value and the correction index are obtained from the steering angle and the vehicle speed. The correction value is obtained by multiplying the detected depression amount and the correction index. The controller determines the differential limiting amount according to the value obtained by adding the reference value and the correction value, and the operating means operates the differential limiting mechanism.

The reference value is given such that it becomes smaller when the steering angle is large, becomes larger when the steering angle is small, becomes larger at low speeds and high speeds, and becomes slightly smaller at medium speeds. By setting the reference value in this way, it is possible to improve the starting acceleration, the high-speed straightness, and the smoothness when changing lanes, and at the same time, avoid the tight corner braking phenomenon during turning.

On the other hand, the correction index is given such that it decreases at low speeds and high speeds, increases at medium speeds, increases when the steering angle is large, and decreases when the steering angle is small. According to this
It is possible to increase the correction value when turning at medium and low speeds and large steering angles without losing the effects of starting acceleration at small steering angles, high speed straightness, smoothness when changing lanes, etc. Therefore, the power controllability can be improved.

(Embodiment) As shown in FIG. 2, the differential control device includes a differential limiting mechanism 1.
0 for controlling the differential of a differential device having 0, means for detecting the vehicle speed, means for detecting the steering angle 14,
It includes a means 16 for detecting the amount of depression of the accelerator, a controller 18 to which a signal from each means is input, and a means 20 for operating the differential limiting mechanism 10.

As the differential device, a known device having a differential limiting mechanism can be used.

In the differential device 22 shown in FIG. 3, one of the shafts 30 is connected to a pair of side gears 28 (both are shown in the drawing) that mesh with a plurality of pinions 26 arranged in the differential case 24. The differential limiting mechanism 10 is provided in association with the differential case 24.

The differential limiting mechanism 10 includes a shaft 32, a spacer 32, and a spacer 32.
A plurality of first friction plates 34 that engage with each other via a transmission member 36 and a plurality of second friction plates 38 that engage with the differential case 24 via a transmission member 36. First friction plate 34
Are supported by the spacer 32 such that they cannot rotate but can move in the axial direction of the shaft 30. On the other hand, the second friction plate 38 is supported by the enlarged diameter portion of the transmission member 36 so as not to rotate and movable in the axial direction. The first friction plate 34 and the second friction plate 38 are arranged alternately.

A piston chamber 42 is formed in the differential carrier 40, and a first piston 44 is movably and non-rotatably arranged in the piston chamber 42. A second piston 46 is spaced from the first piston 44,
The second piston 46 is supported by the spacer 32 such that it cannot rotate but can move in the axial direction. The thrust bearing 48 is used for the first piston 44 and the second piston 4
It is arranged between 6 and 6.

When pressure fluid is introduced into the piston chamber 42 from the outside, the first
The piston 44 of the second through the slide bearing 48
Of the first friction plate 34 and the second friction plate 38, a friction force proportional to the pressing force is generated between the first friction plate 34 and the second friction plate 38. This frictional force limits the differential of the differential device 22.

The vehicle speed detecting means 12 and the rudder angle detecting means 14 can use detectors known per se, and the accelerator depression amount detecting means 16 can be used.
Is composed of a sensor such as a potentiometer whose resistance changes according to the amount of depression of the accelerator.

The controller 18 is a CPU or a computer and receives a signal from each detecting means, determines a differential limiting amount of the differential mechanism 10, and controls the operating means 20, as described later.

As shown in FIG. 2, the operating means 20 includes a liquid pump 50.
Unload relief valve 52 and accumulator 54
A current control pressure reducing valve 56 and a check valve 58.

The pipe 60 is connected to the pump 50 and the differential limiting mechanism 10,
It communicates with the piston chamber 42. Unload relief valve 52
Is incorporated in the pipe 60, and the current control pressure reducing valve 56 is incorporated in a portion from the unload relief valve 52 to the differential limiting mechanism 10. Further, the accumulator 54 is connected between the unload relief valve 52 and the current control pressure reducing valve 56, and the check valve 58 is incorporated between the unload relief valve 52 and the accumulator 54. The check valve 58 only allows liquid flow or pressure transmission from the unload relief valve 52 to the accumulator 54.

When the pressurized fluid is supplied from the pump 50, the unload seat of the unload relief valve 52 is closed and the check valve 58
Opens. As a result, the hydraulic fluid from the pump 50 is guided to the accumulator 54 via the pipe 60, where the hydraulic pressure increases. When the pressure of the accumulator 54 reaches the adjustment pressure of the unload relief valve 52, the unload relief valve 52
Is opened instantly, the pressurized liquid from the pump 50 is circulated to the reservoir tank 62, and the check valve 58 is closed. Thus, a constant pressure is stored in the accumulator 54.

The current control pressure reducing valve 56 is provided with a direct current solenoid in the pilot section, and controls the input current to this solenoid to continuously and steplessly control the pressure. The control pressure in this case is substantially proportional to the input current. Therefore, by controlling the current supplied to the current control pressure reducing valve 56 by the controller 18, an appropriate pressure can be obtained.

The controller 18 controls the operation means 20 by performing the calculation as shown in FIG. After initialization (100), the vehicle speed v is read from the vehicle speed detecting means 12 (101), and the steering angle δ is read from the steering angle detecting means 14 (102).

Based on the read vehicle speed v and the steering angle δ, the reference value P ₀ is obtained from the map stored in advance (10
3). Here, the reference P ₀ can be obtained empirically or experimentally based on the vehicle speed v and the steering angle δ. In the illustrated embodiment, the reference value P ₀ decreases as the steering angle δ increases,
It is given such that it becomes large when the steering angle δ is small, large at low speed and high speed, and slightly small at medium speed.

On the other hand, from the vehicle speed v and the steering angle δ, the correction index or the effectiveness rate k is obtained from the map stored in advance (1
04). Here, the correction index k can be obtained empirically or experimentally based on the vehicle speed v and the steering angle δ. In the illustrated embodiment, the correction index k is small at low speed and high speed,
It is given such that it is large at medium speed, small when the steering angle δ is small, and large when the steering angle δ is large.

After obtaining the correction index k, the accelerator depression amount or accelerator opening θ is read (105), and the correction value ΔP is obtained by multiplying the correction index k and the accelerator depression amount θ (10).
6). Then, the control amount P is obtained as the sum of the reference value P ₀ and the correction value ΔP (107).

A current i that can correspond to the control amount P is obtained from the map (10
8), the current i is output to the current control pressure reducing valve 56 (10
9) At the same time, the above control is repeated (101). The differential limiting amount is proportional to the frictional force generated by the first friction plate 34 and the second frictional plate 38 of the differential limiting mechanism 10, and this frictional force is proportional to the hydraulic pressure supplied to the piston chamber 42. To do. Therefore, the relationship between the differential limiting amount and the hydraulic pressure and the relationship between the hydraulic pressure and the current i necessary for obtaining the hydraulic pressure by the current control pressure reducing valve 56 are previously obtained, and the current satisfying the above relationship from the control amount P is obtained. The map is formed so as to obtain i.

[Brief description of drawings]

FIG. 1 is a control flowchart, FIG. 2 is a block diagram of a differential control device, and FIG. 3 is a sectional view of the differential device. 10: Differential limiting mechanism, 12: Vehicle speed detecting means, 14: Steering angle detecting means, 16: Accelerator depression amount detecting means, 18: Controller, 20: Operating means, 54: Accumulator, 56: Current control pressure reducing valve.

Claims (1)

[Scope of utility model registration request] 1. A device for controlling the differential of a differential device having a differential limiting mechanism, comprising means for detecting a vehicle speed, means for detecting a steering angle, and means for detecting an accelerator depression amount.
The controller is provided with a controller to which a signal from each of the means is input, and means for operating the differential limiting mechanism controlled by the signal from the controller, wherein the controller is a reference value based on a vehicle speed and a steering angle and is low. Based on a reference value that is set to increase at vehicle speed and high vehicle speed, decreases at medium vehicle speed, decreases at large steering angle, and increases at small steering angle, and vehicle speed, steering angle, and accelerator depression amount It is a correction value that decreases at low and high vehicle speeds, increases at medium vehicle speeds, increases when the steering angle is large, and decreases when the steering angle is small. A differential control device that obtains a correction value determined by a product, and outputs a signal according to a value obtained by adding the correction value to the reference value to the operating means.