JPS6382834A - Differential movement restricting device - Google Patents

Abstract

PURPOSE:To improve stability in straight advancement by judging the magnitude of disturbance and that of steering angle and determining whether to apply, or relieve the restriction of, differential movement. CONSTITUTION:A differential movement control device 10 controls the differential movement of a differential device having a differential restricting mechanism 12, and includes a sensor 16 which detects disturbance applied to tires as vertical accelerations, a sensor 18 which detects the magnitude of a steering angle, a controller 20, and an operating means 22. The controller 20 receives signals from the sensors 16, 18 and judges the magnitude of the disturbance as well as the steering angle and determines whether to restrict a differential movement or to remove the restriction of the differential movement.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a differential control device, and more particularly, to a differential control device that controls the differential of a differential device installed in a vehicle that includes a differential; tall limit mechanism. related to a device for

(Prior art) A differential device capable of 11J differential torque is equipped with a differential limiting mechanism consisting of a plurality of friction plates and a hydraulic device for operating these friction plates in addition to a normal differential mechanism. The differential that occurs in the dynamic mechanism is limited by contacting the friction plate. As a result, it is possible to limit or release the differential depending on the running speed and improve running stability (for example,
102324, JP-A-61-102322).

(Problem to be solved by the invention) A vehicle travels straight with the differential of the differential gear being limited,
When the tires are subjected to random disturbances from the road surface, the vehicle becomes unsteady and its ability to drive straight becomes worse.

For example, when the right tire of a moving vehicle lands on a stone or other object and receives a backward force from the road surface, a backward force acts on the rotating shaft of the right tire based on this force, generating a yaw moment. At the same time, the rotational speed of the right tire increases due to the force from the road surface, resulting in a forward force on the rotational axis of the left tire, which further increases the yaw moment. These yaw moments impede the straightness of the vehicle.

SUMMARY OF THE INVENTION An object of the present invention is to provide a differential control device that can prevent a vehicle from wandering due to disturbances that the tires receive from the road surface, and can further improve straight-line driving performance.

(Means for Solving the Problems) The present invention is a device for controlling the differential of a differential gear having a differential limiting mechanism, which includes a sensor that detects disturbances applied to tires from the road surface, and a sensor that detects a large steering angle. a controller that determines the magnitude of the disturbance and the magnitude of the steering angle based on the signals from both sensors, and determines whether to limit the differential or cancel the restriction of the differential; and means for operating the differential limiting mechanism controlled by a signal from the controller.

(Operation and Effect) The controller determines whether the disturbance has reached a predetermined value or not.
It is determined whether the steering angle has reached a predetermined value, it is determined whether the differential should be restricted or the restriction should be canceled, and the operating means is operated. For example, the controller handles the steering angle with priority over disturbances, and releases the differential restriction when the steering angle exceeds a predetermined value.

When disturbances from the road surface are applied to the tires, the restriction on the differential can be canceled, thereby causing a differential between the left and right tires and preventing or suppressing the occurrence of yaw moment due to the disturbance. Thus, straight-line stability is improved.

(Example) As shown in FIGS. 1 and 3, the differential control device 10 controls the differential of a differential device 14 having a differential limiting mechanism 12, and prevents disturbances applied to tires. It includes a sensor 16 that detects vertical acceleration, a sensor 18 that detects the magnitude of the steering angle, a controller 20, and an operating means 22.

Any differential device can be used as long as it has a differential limiting mechanism. The differential device 14 shown in FIG. 3 includes a differential case 24, a plurality of binions 26 and a pair of side gears 28 (one is shown in the figure), and each side gear 28. The shaft 30 is connected to the shaft 30.

The differential limiting mechanism 12 limits the differential movement of the differential device 14, and includes a plurality of first F!s engaged with one side gear 28. Ja plate 32 and differential case 24
and a plurality of second friction plates 34 that engage with each other. A first differential carrier 36 is fixedly disposed surrounding the differential case 24 and rotatably supports the differential case 24. A second differential carrier 38 is attached to the first differential carrier 36.

A cylindrical spacer 40 is attached to the shaft 30,
The first friction plate 32 is supported by the spacer 40 so as to be non-rotatable and movable in the axial direction of the shaft 30 . On the other hand, a transmission member 42 non-rotationally coupled to the differential case 24 is disposed surrounding the shaft 30. The transmission member 42 has an enlarged diameter at a portion beyond the first differential carrier 36, and a second friction plate 34 is supported in this enlarged diameter portion so as to be non-rotatable and movable in the axial direction. The first friction plates 32 and the second friction plates 34 are arranged alternately. A second differential carrier 38 surrounds the transmission member 42 .

The piston chamber 4 is located in the second differential carrier 38.
4 is provided, and a first piston 46 is movably and non-rotatably disposed within the piston chamber 44 . A second piston 48 is spaced apart from the first piston 46 and is non-rotatably and axially movably supported by the spacer 40 . A thrust bearing 50 connects the first piston 46 and the second piston 4
8. When hydraulic pressure is introduced into the piston chamber 44, the first piston 46 is pressed against the second piston 48 via the thrust bearing 50, and between the first friction plate 32 and the second friction plate 34, A friction force proportional to the pressing force is generated. This rr friction force limits the differential movement of the differential device 14.

The controller 20 is a CPU or a computer that receives signals from the sensors 16 and 18, determines the magnitude of the disturbance and the magnitude of the steering angle, and determines whether or not the differential should be restricted or whether the restriction on the differential should be canceled. and control as described below.

In the illustrated embodiment, the operating means 22 includes a liquid pump 52, an unload relief valve 54, an accumulator 56, a current-controlled pressure reducing valve 58, and a check valve p60.

A tube 62 is connected to the pump 52 and the second differential carrier 38 of the differential limiting mechanism 12, and the tube 62 communicates with the piston chamber 44. The unload relief valve 54 is installed in the pipe 62, and the current control valve 58 is installed in the portion leading from the unload relief valve 54 to the differential limiting mechanism 12. Further, an accumulator 56 is connected between the unload relief valve 54 and the current control pressure reducing valve 58, and a check valve 60 is installed between the unload relief valve 54 and the accumulator 56. Reverse valve 60 only allows fluid flow or pressure transmission from unload thief valve 1-54 to accumulator 56.

When pressure fluid is supplied from the pump 52, the unload seat of the unload relief valve 54 is closed, and the check valve 60 is closed.
opens. As a result, pressurized fluid from pump 52 is directed through conduit 62 to accumulator 56, where the fluid pressure increases. The pressure in the accumulator 56 is increased by the unload relief valve 5.
4, the unload relief valve 54 opens instantly and the pressure liquid from the pump 52 is transferred to the reservoir tank 6.
4, and the check valve 60 closes. Thus, a constant pressure is stored in the accumulator 56.

The current-controlled pressure reducing valve 58 is provided with a DC solenoid in its pilot section, and controls the pressure continuously and steplessly by controlling the input current to this solenoid. In this case, the jldJ control pressure is substantially proportional to the input current. Therefore, if the current applied to the current-controlled pressure reducing valve 58 is controlled by the controller 20, an appropriate pressure can be obtained.

The controller 20 makes a determination as shown in FIG. 2, for example, and controls the operating means 22. As mentioned above, since the operating means 22 includes the current-controlled pressure reducing valve 58 that adjusts the pressure steplessly 1110F, the sensor 16 that detects disturbances
In addition to the sensor 18 that detects the steering angle, a vehicle speed sensor 6
A signal from 6 is input to the controller 20 manually.

After initialization (70), the steering angle S is detected from the steering angle sensor 18 (72) and compared with the set value S0 (74). When the steering angle is equal to or greater than the set value, the differential restriction of the differential device 14 is released (76). That is, the differential is made to occur arbitrarily, so that turning can be performed without any support.

When the steering angle S is smaller than the set value S0, the vehicle is traveling straight or almost straight. At this time, the acceleration α is detected from the disturbance sensor 16 (78) and the set value α is set. Compare with (80). When the acceleration is greater than or equal to the set value, k
Release the differential:Ijl limit of the drive device 14''4-ru (76)
. As a result, the occurrence of yaw moment due to disturbance can be prevented or suppressed.

When the acceleration α is smaller than the set value α0, the speed sensor 66
Detect the speed V from 82), set value ■. Compare with (
84). When the speed is equal to or higher than the set value, the pressure P to be applied to the differential limiting mechanism 12 is determined from the speed of the map stored in advance, and the current i that outputs this pressure P is determined (86).

The set speed v0 at this time is a speed at which it is preferable to limit the differential from the viewpoint of improving the running stability of the vehicle.

The controller 20 energizes the current control pressure reducing valve 58 with a current i. Then, the pressure P is differential + t + l J limit machine ellipse 12
The first piston 46 presses the second piston 48 with a force proportional to the pressure. As a result, the first
and the second friction plates 32, 34 contact each other, a friction force proportional to the pressure is generated, and the differential movement of the differential mechanism 12 is limited.

Speed■ is the set value■. When the controller 20 is smaller than
outputs zero current to the current control valve 58 to release the differential restriction (88).

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the differential control device, FIG. 2 is a control flowchart, and FIG. 3 is a sectional view of the differential device. 10: differential control device, 12: differential limiting mechanism, 14: differential device, 16: disturbance sensor, 18: steering angle sensor,
20: Controller, 22: Operating means, 54: Unload relief valve, 56: Accumulator, 58: Current control pressure reducing valve, 66: Vehicle speed sensor. Agent Patent Attorney Nobu Matsunaga Figure 1 Figure 3

Claims (1)

[Claims] A device for controlling the differential of a differential gear having a differential limiting mechanism, which includes a sensor for detecting disturbances applied to the tires from the road surface, a sensor for detecting the magnitude of the steering angle, and signals from both of the sensors. a controller that determines the magnitude of the disturbance and the magnitude of the steering angle based on the magnitude of the disturbance and determines whether to limit the differential or cancel the restriction of the differential; and the differential limiting mechanism that is controlled by a signal from the controller. and means for operating the differential control device.