JPH02199341A - Center differential lock releasing device - Google Patents

Abstract

PURPOSE:To eliminate lock of wheels and increase in braking distance by detecting driving force applied to a center differential of a center differential lock device and by releasing a differential limiting means for limiting rotation difference in front and rear wheels when the driving force is low. CONSTITUTION:In the state where a center differential limiting clutch 30 provided at a center differential device of a four-wheel drive vehicle is released, when a ring gear 31 connected to a transmission is rotated, a center differential case 36 is rotated at the same time, power is transmitted to right a left side center differential gears 34 corresponding to this rotation, and the power is transmitted to a propeller shaft 39 and a front differential case 40. In the state where the clutch 30 is locked, rotation of the right and left side center differential gears 34 and a pinion 33 is limited, and differential motion of the center differential is limited. When low driving force is detected by a throttle opening degree sensor or the like, the clutch 30 is released by operation to a computer for control, and rotation differential limit is released at the time of braking and anti-lock control is carried out for wheels.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention is directed to a four-wheel drive vehicle, in which the difference in rotation between the front drive shaft that drives the front wheels and the rear drive shaft that drives the rear wheels is solved. The vehicle has a center differential that rotates, and a clutch that inhibits relative rotation between the front drive shaft and the rear drive shaft.

The present invention relates to an unlocking device for a center differential device, which includes an operation limiting means for limiting the rotational differential between the front and rear wheels of the center differential, and a wheel opening and lock preventing means for preventing the wheels from being locked by braking the vehicle.

(Conventional technology) Conventionally, in four-wheel drive vehicles, the center differential device is locked when starting on a slippery road, escaping from mud, derailing, etc. when it is desired to prevent a difference in rotation between the front and rear wheels. There is a device. This device detects a rotation difference and locks the center differential device when a rotation difference occurs.

In contrast to this device, there is an anti-lock brake device that prevents wheels from locking when braking a vehicle. When a center differential device is locked in a vehicle equipped with this anti-lock brake device, the rotational speeds of each wheel are related, and it is not possible to sufficiently prevent each wheel from locking.

For this reason, it is desirable to release the restriction on the operation of the center differential immediately before the wheels lock or when the anti-lock brake control device starts operating. Such a device is disclosed, for example, in Japanese Patent Laid-Open No. 1539/1983.

(Problem to be Solved by the Invention) In this device, when the center differential operation restriction is canceled just before the wheels are locked or when the anti-lock brake control device starts operating, it takes a long time to actually cancel due to the device operation delay. It may take some time. In this case, it is expected that the performance will deteriorate, such as the wheels locking before the actual release.

Therefore, the technical object of the present invention is to reliably release the restriction on the operation of the center differential when braking the vehicle.

[Structure of the invention]

(Means for Solving the Problems) In the present invention, in order to solve the above problems, the driving force detection means for detecting the driving force applied to the center differential and the detection value of the driving force detection means indicate a low driving force. In this case, a release means for releasing the rotational differential restriction of the operation restriction means is used.

(Function) According to the above means, when the driving force applied to the center differential is reduced, the rotational differential restriction of the center differential operation limiting means is released. As a result, the moment you take your foot off the accelerator to apply the brake, the engine's driving force decreases and the rotational differential restriction is released. Therefore, when the vehicle is braked, the rotational differential restriction is released.

(Example) Embodiments of the present invention will be described below with reference to the accompanying drawings.

Referring to FIG. 2, four wheels 5a, 5b.

5c and 5d each have a brake 41a.

41b, 41C and 41d are arranged, and these 4
The two brakes are controlled by the anti-lock control device 7 to maintain the optimum slip ratio of each wheel.

The driving force of the engine 8 is transmitted by the transmission 9. Center differential 18. It is transmitted to the respective wheels 5a, 5b, 5c and 5d via the front differential 6a and rear differential 6b.

The center differential 18 is a computer for controlling the center differential.
Controlled by O. Referring to FIG. 3, a center differential control computer 10 installed inside the vehicle includes a center differential control switch 11, a speed sensor 12. Rear speed sensor 13, stop lamp switch 14.
A throttle opening sensor 15 and the like are connected. The center differential control switch 11 is a switch for selecting whether or not to operate the center differential. Speed sensor 1
2 is a sensor for measuring the speed of the vehicle. The rear speed sensor 13 is a sensor for detecting rear wheel speed. The stop lamp switch 14 is a switch that turns on a stop lamp, and is linked to the foot brake. When the brake is depressed, the stop lamp switch 14 is turned on and a signal is input to the center differential control computer 10. The throttle opening sensor 15 is a sensor for detecting the opening of a throttle valve of a vehicle.

A solenoid valve 16 is also connected to the center differential control computer 10. The solenoid valve 16 is operated by a signal from the center differential control computer 10, and controls the discharge of fluid in the fluid path 19b. When the solenoid valve 16 is turned on, the discharge of fluid in the fluid path 19a is stopped, fluid flows from the fluid path 19a into the fluid path 19b, and the pressure in the fluid path 19b increases.

When the solenoid valve 16 is turned off, the fluid in the fluid path 19a is discharged, and the pressure in the fluid path 19b decreases. Fluid path 19b is connected to shift valve 17. Shift valve 17 operates depending on the pressure within fluid path 19b.

When the pressure within fluid path 19b increases, fluid path 19d is blocked. When the pressure in fluid path 19b decreases, fluid path 1
9c and the fluid path 19d are connected, the fluid from the fluid path 19C flows into the fluid path 19d, and the pressure in the fluid path 19d increases. The fluid path 19d is connected to the center differential device 18. When the pressure in the fluid path 19d increases, the center differential differential limiting clutch in the center differential device operates differentially, and the center differential is locked. Therefore, the locking of the center differential can be controlled in response to the signal from the center differential control computer.

The center-differential control computer 10 operates according to the flowchart shown in FIG. Referring to FIG. 1, when the center differential control computer 10 starts, initialization is first performed (step 20). Next, center differential control switch 11. Speed sensor 12
．． Rear speed sensor 13. Stop lamp switch 1
4. The state of each input of the throttle opening sensor 15 is read and calculation processing is executed (step 21). Here, vehicle speed calculation, rear wheel speed calculation, throttle opening calculation, etc. are performed. Next, processing for limiting differential movement of the center differential is performed (step 22).

Here, center differential control switch 11. Speed sensor 12. Rear speed sensor 13. Depending on the input status of the stop lunge inch 14, etc., we do not want to create a difference in rotation between the front and rear wheels when starting on a slippery road, escaping from mud, or when derailing, as is done with conventional devices. The center differential will be locked in this case. Thereafter, in step 23, it is determined whether the throttle opening is fully closed, and if the throttle opening is fully closed, an instruction to turn on the solenoid valve 16 is given (step 24). Thereafter, the above process is repeated.

When the solenoid valve 16 is turned on, the center differential differential limiting clutch is released. The operation of the center differential will be explained with reference to FIG. Ring gear 31 is connected to a transmission (not shown). When the center differential differential limiting clutch 30 is released, when the ring gear 31 rotates, the ring gear mounting case 35 fixed to the ring gear 31. and the center differential case 36 rotate at the same time. Center differential case 3
Inside 6 are the right side and left side center differential gears 3.
4 and a center differential binion 33 are disposed, and power is transmitted to the right side and left side center differential gears 34 in accordance with the rotation of the center differential case 36. The power transmitted to the right side center differential gear is transferred to the transfer mounting case 37. It is connected to a propeller shaft 39 via a transfer drive gear 32 and a transfer driven gear 38.

The power transmitted to the left side center differential gear is transmitted to the front differential via the front differential case 40.

When the center differential differential limiting clutch is locked, the ring gear mounting case 35 and the front differential case 40 are locked and rotate at the same time. Therefore, the rotation between the right side and left side center differential gears 34 and the center differential pinion 33 is restricted, and the differential movement of the center differential is restricted.

In this embodiment, a center differential that differentially rotates the front drive shaft that drives the front wheels and a rear drive shaft that drives the rear wheels, and a clutch (center differential) that prohibits relative rotation between the front drive shaft and the rear drive shaft are used. a differential limiting clutch), and an operation limiting means (a center differential control computer, a solenoid valve, a shift valve, a center differential differential limiting clutch) for limiting the rotational differential between the front and rear wheels of the center differential; The vehicle is equipped with an anti-lock control device and a brake, which is a wheel lock prevention means that prevents the wheels from being locked by braking. A throttle opening sensor is a driving force detecting means for detecting the driving force applied to the center differential, and when the detected value of the throttle opening sensor indicates a low driving force, the rotation differential restriction of the operation limiting means is performed. Steps 23 and 24, which are release means for release, are provided. As a result, when the driving force decreases, the center differential differential limiting clutch is released, and the center differential differential limiting is released.

Therefore, when the accelerator is not depressed, differential restriction of the center differential is not performed.

In this embodiment, the center differential differential limiting clutch is released when the throttle opening is fully closed, but it may be released when the throttle opening is close to fully closed.

The throttle opening corresponds to the driving force applied to the center differential and is easily detected, so it is adopted in this embodiment. The driving force applied to the center differential may be detected instead of the throttle opening, and the differential restriction may be canceled when the driving force indicates low driving.

〔Effect of the invention〕

As described above, according to the present invention, since the rotational differential restriction is canceled when the vehicle is braked, antilock brake control is always normally executed. Therefore, there is no locking of the wheels and no increase in braking distance.

[Brief explanation of the drawing]

FIG. 1 is a flowchart of a center differential control computer according to an embodiment of the present invention. 2 and 3 are circuit configuration diagrams of a device using the center differential lock release device of the present invention. FIG. 4 is a configuration diagram of the center differential used in this example. 5a to 5d...Wheels, 6a...Front differential, 6b...Rear differential, 7...Anti-lock device (wheel lock prevention means 10)
・ ・ 11 ・ ・ l 5 ・ ・ stage), 16 ・ ・ ・ 17 ・ ・ ・ l 8 ・ ・ 19a~1 30 ・ ・ ・ Sochi), ・Center differential control computer, ・Center differential control switch, ・Throttle Opening sensor (driving force detection hand solenoid valve, shift valve, center differential, 9d...fluid path, center differential differential limiting clutch (claring gear, transfer drive gear, center differential pinion, center differential gear, ring gear mounting case) , Center differential case, Transfer ring mounting case 31, 32, 33, 34, 35, 36, 37, -S, 38...Transfer driven gear, 39...Propeller shaft, 40...Front differential case, 41a to 41d ... Brake. Figure 1 Figure 3 Figure 2

Claims (2)

[Claims] (1) A center differential that differentially rotates a front drive shaft that drives the front wheels and a rear drive shaft that drives the rear wheels; a clutch that prohibits relative rotation between the front drive shaft and the rear drive shaft; In a center differential lock release device that is equipped with an operation limiting device that limits the differential rotation between the front and rear wheels of the differential, and a wheel lock prevention device that prevents the wheels from being locked by braking the vehicle, the driving force applied to the center differential is detected. A center differential lock release device comprising: a driving force detecting means for detecting a low driving force; and a canceling means for canceling rotational differential restriction of the operation restricting means when a detected value of the driving force detecting means indicates a low driving force. (2) Furthermore, it has a timer means that starts after the detection value of the driving force detecting means detects a low opening, and the canceling means controls the rotation differential restriction of the operation limiting means after the timer means finishes counting. The center differential lock release device according to claim 1, which releases the center differential lock.