JPH06227276A - Center differential gear - Google Patents

Abstract

PURPOSE:To quickly disengage a differential lock means in engaged state by forming the tooth shape of a crown gear with such an angle as to generate a slip-off force with a driving torque, and furnishing an actuator with which the crown gear is retained in the engaged state with a force exceeding the slip-off force. CONSTITUTION:A differential lock means capable of being disengaged is furnished at a branch point for transmitting the driving torque from one engine to the front axle and rear axle of a four-wheel driving car and coupled with the drive shafts of the front and rear axles through crown gears 1. The tooth shape of the crown gears capable of being engaged by and disengaged from each other, is formed at such an angle as to generate a slip-off force with the driving torque, and an actuator is furnished which holds the engaged state of the crown gear 1 with a force exceeding this slip-off force. The actuator includes a fluid pressure cylinder 2, is installed in a center differential gear case 3, and is controlled with a control signal of an anti-lock brake device.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention finds application in motor vehicles, especially four-wheel drive vehicles (4WD).

[0002] The present invention is an anti-lock brake device (AB) for automatically controlling the brake hydraulic pressure for each wheel so that the wheels do not lock even when sudden braking is applied on a slippery road surface.
S, Antilock Brake System), but it can be implemented without using it together with an antilock brake device.

In the present specification, a four-wheel drive vehicle includes a six-wheel drive vehicle or an all-wheel drive vehicle.

[0004]

2. Description of the Related Art In a four-wheel drive vehicle, a gear for distributing a driving force to a front shaft and a rear shaft is provided with a center differential gear that absorbs a rotation difference between the front shaft and the rear shaft. Further, the center differential gear is provided with a lock means for temporarily fixing the differential mechanism. The differential lock means of the center differential gear is generally structured to be set or released by a driver's lever operation or switch operation. The driver operates and sets the differential lock mechanism of the center differential gear when recognizing that the wheels run idle when a strong driving force is applied on a slippery road surface. When the vehicle travels for a long time with the differential lock means set, tire wear increases, so it is preferable to release the differential lock mechanism when traveling on a good road surface. As a conventional structure for this purpose, a structure in which a concentric type spline is driven by an actuator is widely known.

On the other hand, a four-wheel drive vehicle has also been equipped with an anti-lock braking device. The anti-lock braking device incorporates the signal from the rotation sensor attached to each wheel into the program control circuit and individually controls the brake hydraulic pressure of each wheel when it is determined that one of the wheels tends to lock. It is a device that sends a control signal to an actuator that can perform real-time control so that the brake hydraulic pressure of each wheel becomes appropriate. This device is extremely effective on snowy roads, rainy roads, frozen roads, etc.
As a device that can be steered even when sudden braking is applied, the safety of vehicle running is enhanced.

In a four-wheel drive vehicle, in principle, each wheel cannot rotate freely when the differential gear is locked. This also applies to the center differential gear, and when the center differential gear is in a locked state, the antilock brake device that operates by detecting the rotation of each wheel does not operate well.

[0007]

SUMMARY OF THE INVENTION In order to effectively operate the anti-lock braking device, the present invention is a device for automatically releasing the locking means of the center differential gear when the anti-lock braking device operates. It was proposed in accordance with the invention of.

The conventional locking means for the center differential gear has a slow response to the release command. Therefore, there is a drawback that the locking means cannot be effectively released in accordance with a command from the antilock / brake device.

An object of the present invention is to improve the above and to provide a center differential gear capable of releasing the locking means within a short time after a control command is issued.

[0010]

The first feature of the present invention is:
As a differential lock means, a pair of crown gears which are respectively connected to the drive shafts of the front axle and the rear axle and which can be fitted and disengaged from each other are used. Secondly, the tooth shape of the crown gear is formed at an angle that generates a pull-out force by the driving rotational force, and in a locked state, an actuator that holds the crown gear in a fitted state with a force exceeding this pull-out force. Is equipped with.

The actuator may include a fluid pressure cylinder, and the cylinder may be arranged in the center differential gear case.

The actuator can be controlled by a control signal of the antilock braking device.

The four wheels mean at least four wheels, and a six-wheel or all-wheel drive vehicle is also included in the present invention.

[0014]

The crown gear, which generates the pulling force by the driving torque, quickly releases the fitted state by releasing the holding force by the actuator when there is a difference in rotation between the two branched outputs.

Therefore, when a control signal arrives from the anti-lock braking device and the anti-lock braking device starts to operate, the fitted state can be quickly disengaged and the anti-lock braking device can be activated. .

[0016]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a sectional view of a main part showing a configuration of an embodiment of the present invention, FIG. 2 is a view showing a shape of a crown gear in the embodiment of the present invention, and FIG. 3 is a view showing a main part of a circuit configuration of the embodiment of the present invention. is there.

The embodiment of the present invention is provided with a disengageable differential lock means provided at a branch point for transmitting a driving torque from one engine to the front and rear axles of a four-wheel drive vehicle. The locking means are respectively connected to the drive shafts of the front axle and the rear axle, and include a pair of crown gears 1 that can be fitted and disengaged from each other, and the tooth shape of the crown gears 1 generates a pulling force by the driving rotational force. An actuator that is formed at an angle and that holds the crown gear 1 in a fitted state by a force that exceeds this pulling force is provided. This actuator comprises a hydraulic cylinder 2 and is arranged in a center differential gear case 3, said actuator being controlled by a control signal of an antilock braking device.

Further, as shown in FIG. 3 as an electric circuit, a relay circuit 12 which makes a break operation by the ABS signal output from the program control device 11 when the antilock brake device operates, and the relay circuit 12 is in an open state. Solenoid valve 14 that stops the pressure supply from the pressure source 13 to the fluid pressure cylinder 2 when it becomes, a differential lock switch 15 that manually sets and disengages the locked state of the front axle and the rear axle, and the driver seat. The operation indicator lamp 16 is provided to display the operation of the relay circuit 12.

Further, the program control unit 11 is provided with an AB
It includes means for automatically resetting the locked state of the center differential gear after the S signal disappears and a predetermined time has elapsed.

Next, the operation of the embodiment of the present invention thus constructed will be described.

When the diff lock switch 15 is manually set to the closed state, the current from the power source is operated by the solenoid valve 14 via the contact 12b of the relay circuit 12 which is normally set to the closed state. The conduit to the fluid pressure cylinder 2 is opened. When the pipeline is opened, fluid pressure is applied to the fluid pressure cylinder 2, and one of the axially movable crown gears 1 is moved via the bearing 4 and fitted to the other of the fixed crown gears 1. . As a result, the front axle and the rear axle are locked. In addition, the return sprig 5 is brought into a compressed state as the crown gear 1 moves, and is locked in a state in which a biasing force is applied in a direction of separating the two crown gears 1.

When the anti-lock brake device is activated while the front axle and the rear axle are in the locked state, the program control device 11 sends an AB signal to the relay circuit 12.
The S signal is output. This output excites the coil 12a of the relay circuit 12 to open the contact 12b.
When the contact 12b is in the open state, the supply of current from the power source to the solenoid valve 14 is stopped, the pipeline from the pressure source 13 to the fluid pressure cylinder 2 is closed, and the pressing of the crown gear 1 by the fluid pressure is stopped. At the same time, the operation indicator lamp 16 provided in the driver's seat is lit to indicate that the locked state has been released.

When this pressing is stopped, a pull-out force (f ₁ · cos α) is generated in the crown gear 1 due to the difference in driving rotational force between the front axle and the rear axle, as shown in FIGS. Upon receiving the biasing force of the return spring 5 in the compressed state, the fitted state of the crown gear 1 is immediately disengaged, and the operation of the antilock brake device is enabled.

When the operation of the anti-lock / brake device is stopped, the ABS signal output from the program control device 11 disappears, but the contact 12b of the relay circuit 12 is maintained in the closed state. At this time, the lock release of the center differential gear is displayed on the driver's seat. This is closed again by another reset operation, and current is supplied to the solenoid valve 14. By supplying this electric current, the conduit from the pressure source 13 to the fluid pressure cylinder 2 is opened, and the crown gear 1 is fitted to lock the front axle and the rear axle.

Further, the program control device 11 automatically puts the differential gear in the locked state when a predetermined time elapses after the signal indicating the operation of the antilock / brake device to the operation indicator lamp 16 disappears.

As the device for automatically setting the lock state, a known control device for setting the lock state during traveling is used. Since this is not directly related to the present invention, it will be briefly described. When the sensor output for detecting the rotations of the front axle and the rear axle has a small rotation difference, the solenoid valve 14 is energized to set the crown gear 1 to the locked state. To do.

[0027]

As described above, according to the present invention, when the antilock brake device starts to operate, the lock state between the front axle and the rear axle is quickly disengaged, and the antilock brake device is released. There is an effect that can be activated.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing the shape of a crown gear according to the embodiment of the present invention.

FIG. 3 is a diagram showing a main part of a circuit configuration according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating a pulling force generated in the crown gear according to the embodiment of the present invention.

[Explanation of symbols]

 1 Crown Gear 2 Fluid Pressure Cylinder 3 Center Differential Gear Case 4 Bearing 5 Return Spring 11 Program Controller 12 Relay Circuit 12a Coil 12b Contact 13 Pressure Source 14 Solenoid Valve 15 Differential Lock Switch 16 Operation Indicator Light

Claims (3)

[Claims] 1. A branch point for transmitting a driving torque from one engine to a front axle and a rear axle of a four-wheel drive vehicle,
In a center differential gear having a releasable differential lock means, the differential lock means includes a pair of crown gears that are respectively coupled to drive shafts of a front axle and a rear axle and can be fitted and disengaged from each other, The tooth shape of the crown gear is formed at an angle that generates a pull-out force by the driving rotational force, and a center is provided with an actuator that holds the crown gear in a fitted state by a force exceeding the pull-out force. Differential gear. 2. The center differential gear according to claim 1, wherein the actuator includes a fluid pressure cylinder, and the cylinder is arranged in a center differential gear case. 3. The actuator is an antilock
The center differential gear according to claim 1, which is controlled by a control signal of a brake device.