JPH0120180Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a control device for a four-wheel drive vehicle.

BACKGROUND TECHNOLOGY A motor vehicle has a front wheel input shaft and a rear wheel input shaft that transmit the output of a power unit consisting of an engine, a clutch mechanism, a transmission, etc. to front wheel side and rear wheel side differential devices, respectively. Various types of constant four-drive automobiles in which a center differential device is interposed between the input shafts have been developed in the past (for example, see Japanese Patent Laid-Open No. 11961/1983).

Problems to be Solved by the Invention In the above-mentioned four-wheel drive vehicle, the center differential device interposed between the front and rear input shafts is designed to This is necessary to absorb the difference in rotation between the rear wheels and make a smooth turn, but the center differential device also absorbs the difference in rotation between the front and rear wheels even when driving straight, other than when turning. Since it is possible
When one of the front and rear wheels spins with respect to the road surface, the driving torque of the other wheel decreases significantly. Therefore, conventionally, a center differential lock device is provided which locks the center differential device and directly connects the front and rear input shafts, and the center differential device can be locked by manual operation by the driver (for example, by operating a switch). When escaping from extremely uneven roads or sandy areas, the center differential device is manually locked and the front and rear wheels are directly connected, making it easier to escape. ing.

However, when accelerating suddenly during normal driving, the ground resistance of the front wheel is smaller (due to changes in weight distribution due to acceleration, the vehicle weight of the front wheels is smaller than that of the rear wheels, and the ground resistance of the front wheels is also smaller). ) tend to spin, causing a problem in which acceleration efficiency deteriorates, but when driving in general with repeated sudden accelerations and decelerations, the driver manually locks the center differential lock every time there is a sudden acceleration. In practice, it is almost impossible to manually release the lock again after sudden acceleration has finished, as the driver's operations are too complicated, and the vehicle's original acceleration ability cannot be fully utilized. The current situation is that it is being used as is.

The present invention aims to solve the above-mentioned conventional problems.

Means for Solving the Problems The present invention provides a center differential device between the front wheel input shaft and the rear wheel input shaft, and locks the center differential device by manual operation. 4 with manual locking means to
In a wheel drive vehicle, a sudden acceleration sensor is provided, which comprises an accelerator pedal depression detection means that issues a signal when the accelerator pedal is depressed greatly, and a vehicle speed detection means that issues a signal when the vehicle speed is less than a set vehicle speed, and the sudden acceleration sensor The present invention is characterized in that automatic locking means is provided for locking the center differential device when both the accelerator pedal depression detection means and the vehicle speed detection means issue signals.

Effect With the above configuration, when the driver depresses the accelerator pedal greatly at low speeds and accelerates suddenly, the sudden acceleration sensor detects this before the wheels start spinning, issues a sudden acceleration signal, and automatically The center differential device is locked and the front and rear wheels are directly connected, greatly reducing wheel spin.When the vehicle speed increases to a certain extent and the transient state of sudden acceleration ends, the sudden acceleration sensor stops sending the sudden acceleration signal. The lock of the center differential device is automatically released, thereby improving acceleration efficiency during sudden acceleration without requiring complicated operations by the driver.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In the figure, 1 is a transmission (a manual transmission is shown, but an automatic transmission may also be used), and an output shaft 2 of the transmission 1 is connected to a front wheel side input shaft via a center differential device 3. 4 and the rear wheel side input shaft 5.

The front wheel input shaft 4 transmits power to the front wheels via a front differential device 6 and left and right front axle shafts (not shown), and the rear input shaft 5 transmits power to the front wheels via a front differential device 6 and left and right front axle shafts (not shown). Power is transmitted to the rear wheels via a shaft.

Reference numeral 7 designates a center differential lock device comprising a wet type multi-disc clutch that locks the center differential device 3 and directly connects both input shafts 4 and 5 on the front and rear wheels.

8 is a hydraulic pump; 9 is a switching valve; the switching valve 9 controls opening and closing of an oil passage 10 for supplying oil discharged from the hydraulic pump 8 to the center deflock device 7;

Reference numeral 11 denotes an electromagnetic solenoid, and when both the ignition switch 13 and the manual defroster switch 14 are on, the electromagnetic solenoid 1 is connected to the power source 12.
1, a current flows through the actuating piece 1 of the electromagnetic solenoid 11.
1a protrudes and operates to open the switching valve 9,
By turning off the ignition switch 13 or manual defroc switch 14, power to the electromagnetic solenoid 11 is cut off, and the switching valve 9 is returned to its original closed state by a return spring. 15 is a defrock indicator.

Reference numeral 16 indicates an accelerator pedal switch that is turned on when the accelerator pedal 17 is fully depressed, and reference numeral 18 is a vehicle speed switch that is turned on when the vehicle speed V is smaller than a set value _V0 . sensor 19
When both the accelerator pedal switch 16 and the vehicle speed switch 18 are on, that is, when the accelerator pedal 16 is depressed greatly but the vehicle speed is low, the electromagnetic solenoid 11 determines that the state is a sudden acceleration state. The electromagnetic solenoid 11 connects the AND circuit 21 that energizes and opens the switching valve 9.
Manual defrot switch 14 of the manual energization circuit to
are connected in parallel.

A relay 20 is turned on when the vehicle speed switch 18 is turned on.

In the above, when the driver turns on the manual differential switch 14 when exiting from a rough road, for example, the electromagnetic solenoid 11 is actuated, the switching valve 9 is opened, and the hydraulic pump 8 passes the oil passage 10 to the center differential lock device 7. As with the conventional device, hydraulic oil is supplied to the center differential device 3 to lock the center differential device 3, and both the front and rear input shafts 4 and 5 are directly connected, making it possible to easily escape from a rough road.

During normal driving without turning on the manual differential switch 14, the accelerator pedal 1 is turned off from a low speed state.
When accelerating suddenly by depressing the accelerator pedal 7, the accelerator pedal switch 16 and the vehicle speed switch 18 are both turned on because the vehicle speed is still low at the beginning of the accelerator pedal depression.
The AND circuit 21 containing 0 becomes conductive, and the electromagnetic solenoid 11 is energized from the power supply 12 and the ignition switch 13 through the AND circuit 21, and the switching valve 9 is automatically opened and the center differential lock device is activated. 7 is activated to lock the center differential device 3, directly connecting the front and rear wheels and significantly reducing front wheel slippage during sudden acceleration.

When the vehicle speed exceeds the set vehicle speed _V0 of the vehicle speed switch 18 due to the sudden acceleration, the vehicle speed switch 18 is turned off, the relay 20 is turned off, and the AND circuit 2
1 becomes non-conducting, power to the electromagnetic solenoid 11 is cut off, the switching valve 9 is closed, and the locking of the center differential device 3 by the center differential lock device 7 is automatically released.

Effects of the invention As described above, according to the invention, sudden acceleration can be detected in a four-wheel drive vehicle equipped with a center differential device and a center differential lock device that manually locks the center differential device. The sudden acceleration sensor is composed of an accelerator pedal depression detection means that emits a signal when the accelerator pedal is depressed greatly, and a vehicle speed detection means that emits a signal when the vehicle speed is less than a set value, and both the accelerator pedal depression detection means and the vehicle speed detection means are configured. With an extremely simple configuration that only requires the addition of a means for locking the center differential lock device when the system issues a signal,
Sudden acceleration is detected before the wheels actually begin to spin, and the center differential device is automatically locked to connect the front and rear wheels directly, significantly reducing wheel spin and significantly improving acceleration efficiency. It is something that can be measured and can have great practical effects.

[Brief explanation of the drawing]

The accompanying drawing is an explanatory diagram showing an embodiment of the present invention. 2... Output shaft, 3... Center differential device, 4... Front wheel side input shaft, 5... Rear wheel side input shaft, 7... Center differential lock device, 9... Switching valve, 11... Electromagnetic solenoid, 14... Manual defroster switch, 19... Rapid acceleration sensor, 21
...AND circuit.

Claims (1)

[Scope of utility model registration request] A four-wheel drive system equipped with a center differential device interposed between the front wheel input shaft and the rear wheel input shaft, and a center differential lock device that locks the center differential device by manual operation. In an automobile, a sudden acceleration sensor is provided, which includes an accelerator pedal depression detection means that detects when the accelerator pedal is depressed significantly and issues a signal, and a vehicle speed detection means that detects that the vehicle speed is lower than a set value and issues a signal. A control device for a four-wheel drive vehicle, comprising automatic locking means for locking the center deflock device when both the accelerator pedal depression means and the vehicle speed detection means of the sudden acceleration sensor emit signals. .