JPH0319467Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to a switching device for a four-wheel drive vehicle.

(Prior Art) As a conventional switching device for a four-wheel drive vehicle, there is, for example, one shown in FIG. 2 (MITSUBISHI New Model Car Handbook, CHARIOT, page 24, published by Mitsubishi Motors Corporation, June 1984). This shows the entire transfer system of a part-time four-wheel drive vehicle, where 1 is the front differential, 2 is the drive shaft, 3 is the rear output clutch shaft, 4 is the transfer case, 5 is a keyway, 6 is a clutch sleeve, 7 is a clutch hub, 8 is a rear output pinion, 9 is a speedometer drive gear, 10
is the rear output pinion cover, 11 is the differential drive gear, 12 is the drive shaft, 13 is the spring, 14 is the shift rail, 15 is the select actuator, 16 is the shift fork, 17 is the upper cover, 18 is the engagement switch It is.

The operation of the switching device 19 in such a transfer device will be explained. When transitioning from two-wheel drive to four-wheel drive (only the front wheels), manually push the changeover switch (not shown) in the driver's cab, energize the solenoid valve (not shown) in one direction, and switch one side of the select actuator 15. When the inlet manifold negative pressure is applied to the chamber 15a, the clutch sleeve 6 is moved by the shift fork 16 and engages with the keyway 5 of the rear output clutch shaft 3. As a result, the rear output clutch shaft 3 is rotationally driven, and power is also transmitted to the rear wheels (not shown).

When returning to two-wheel drive, press the changeover switch again, switch the solenoid valve (not shown), and apply inlet manifold negative pressure to the other chamber 15b of the select actuator 15, so that the clutch sleeve 6 Move to the middle right and keyway 5
By disengaging the switching device 19
is released, and the transmission of power to the rear wheels is interrupted.

(Problems to be Solved by the Invention) However, the switching device 19 of such a conventional four-wheel drive vehicle is a manual type and has a structure in which the parking brake is installed only on one of the rear wheels or the front wheels. Therefore, if the parking brake is applied and the vehicle is parked in two-wheel drive on a relatively steep slope, and the load on the rear or front wheels with the parking brake applied is reduced, the vehicle may slide off. Ta. For example, if a truck with large load changes is parked on a downhill road with the parking brake applied to the rear wheels, the load on the rear wheels decreases as the vehicle is unloaded and the braking force decreases, causing the vehicle to slide down.

(Means and effects for solving the problem) This invention was made in view of the problems of the conventional technology, and its configuration is to connect the front wheel side and the rear wheel side to create a two-wheel drive system. In a switching device for a 4-wheel drive vehicle that switches between 4-wheel drive and 4-wheel drive using a drive mechanism,
A vehicle speed detection means for detecting a stopped state of the vehicle and a parking brake detection means for detecting an operating state of the parking brake are provided, and the vehicle speed detecting means detects the stopped state of the vehicle and the parking brake detecting means detects the operating state of the parking brake. This is a switching device for a four-wheel drive vehicle that controls switching of the drive mechanism to the four-wheel drive side when detecting this.

When the vehicle stops and the vehicle speed detection means generates a detection signal, and the parking brake operates and the parking brake detection means generates a detection signal, the switching device automatically switches to the four-wheel drive side. .

(Example) Hereinafter, an example of this invention will be described with reference to the drawings.

In FIG. 1, reference numeral 20 indicates a switching device for a four-wheel drive vehicle, 3 is a rear output clutch shaft, 4 is a transfer case, 5 is a keyway, and 6 is a rear output clutch shaft.
1 is a clutch sleeve, 7 is a clutch hub, and 8 is a rear output pinion, and the above structure is substantially the same as that of the conventional example.

Reference numeral 20 denotes a drive mechanism that provides reciprocating linear motion to the clutch sleeve 6. When the solenoid 21 is energized, the operating lever 23, which has been returned to its original position by the return spring 22, protrudes to the left in the figure, causing the clutch sleeve 6 to move in a straight line. Rear output clutch shaft 3
It is designed to engage with the keyway 5 of.

A brake switch 24 is a parking brake detection means for detecting the operating state of the parking brake, and closes the circuit when the parking brake lever 25 is operated.

26 is a speed switch which is a vehicle speed detection means for detecting the zero running speed of the vehicle, and the pointer 2 of the speed meter 27 is
When 7a indicates 0 km/h, the circuit is closed.

This brake switch 24, speed switch 26
and solenoid 21 connects conductor 3 to power supply 28.
They are connected in series at 0.

Next, the effect will be explained. When the vehicle is stopped and the parking brake lever 25 is pulled with the slope 27a of the speedometer 27 indicating 0 km/h, the speed switch 26 and the brake switch 24 are both closed, and the power supply 28 is connected to the solenoid 21. Power is applied. As a result, the operating rod 23 protrudes against the restoring elastic force of the return spring 22.
The clutch sleeve 6 is engaged with the keyway 5, the rear output clutch shaft 3 and the rear output pinion 8 are connected, and a four-wheel drive state in which the front wheel side and the rear wheel side are directly connected is obtained. As a result, the parking brake on the rear wheels or front wheels generates a braking force on the front wheels or rear wheels that are not equipped with a parking brake, and the vehicle is prevented from sliding down.

If you release the parking brake lever 25,
Since the brake switch 24 is opened, the operating lever 23 returns to the right side in the figure along with the clutch sleeve 6 due to the action of the return spring 22, and the clutch sleeve 6 is disengaged from the keyway 5, resulting in two-wheel drive. become.

By the way, as shown in FIG. 1 by imaginary lines, there is a tilt switch 29 for detecting the tilt angle of the vehicle.
, brake switch 24 and speed switch 2
6 in series, and the vehicle can be switched to four-wheel drive only when the additional condition that the vehicle tilts at a predetermined angle θ is satisfied.

In addition, the brake switch 24 is replaced with a displacement sensor that converts a magnetic quantity into an electrical quantity, and the speed switch 26 is replaced with a rotation speed sensor, and when detection signals are generated by both sensors, the switching device 20 is switched to the four-wheel drive side. It is also possible to switch to .

(Effects of the invention) As can be understood from the above explanation, according to this invention, when a vehicle is parked, it automatically switches to four-wheel drive and improves braking force. It is possible to prevent the vehicle from sliding down when the vehicle is in a state of failure, thereby improving the safety of the vehicle.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram showing one embodiment of this invention, and FIG. 2 is a sectional view showing a conventional structure. 3: Clutch shaft (rear wheel side), 8: Rear output pinion (front wheel side), 20: Drive mechanism,
24: Brake switch (parking brake detection means), 26: Speed switch (vehicle speed detection means).

Claims (1)

[Scope of utility model registration request] By intermittent front and rear wheels, two-wheel drive and four-wheel drive are possible.
In a switching device for a four-wheel drive vehicle that switches between wheel drive and wheel drive using a drive mechanism, a vehicle speed detection means for detecting a stopped state of the vehicle and a parking brake detection means for detecting an operating state of a parking brake are provided,
4. When the vehicle speed detection means detects a stopped state of the vehicle and the parking brake detection means detects an operating state of a parking brake, the drive mechanism is switched to a four-wheel drive side.
Switching device for wheel drive vehicles.