JPH0242871U - - Google Patents

Description

[Brief explanation of drawings]

The attached drawings show an embodiment of the rear wheel steering device according to the present invention, in which Fig. 1 is an overall configuration diagram, Fig. 2 is a characteristic diagram of the rear wheel steering angle with respect to the front wheel steering angle, and Fig. 3 is a diagram showing the characteristics of each pressure control valve. FIG. 4 is a characteristic diagram of the relief pressure generated in the front wheel steering angle. Explanation of symbols, 20... Rear wheel power steering device, 21
...input member, 23...servo valve (rear wheel servo valve),
25... Operating rod (rear wheel operating rod), 26... Rear wheel power cylinder, 28... Return spring, 29... Return spring, 31a, 31b... Pressure control valve, 33... 4 port 3 position switching valve, 33a, 33b... Inlet Port, 33c, 33d...Outlet port, 34a, 34b
... Throttle (fixed throttle), 35a, 35b... Working cylinder, 36a, 36b... Working chamber, 37a... Supply pump (front wheel side pump), 37b... Supply pump (rear wheel side pump), 38a, 38b... Piping, 40 ...control device, 41...vehicle speed sensor, 42...oil temperature sensor.

Claims (1)

[Scope of utility model registration request] A rear wheel power cylinder that operates an operating rod, a return spring that returns the operating rod to a neutral position, and a supply pump that supplies working fluid to both working chambers of the rear wheel power cylinder according to the amount of operation of the input member. A rear wheel power steering device comprising a servo valve for exhaust control and steering the rear wheels via the actuating rod includes a pair of pipes to which working fluid is supplied from a supply pump; It is provided in each pipe and is operated in conjunction with the steering of the front wheels, so that the working fluid pressure in each pipe is 0 at the front wheel steering neutral position, and when the front wheels are steered in one direction, the hydraulic fluid pressure in one pipe is A pressure control valve that increases the working fluid pressure in accordance with the steering angle and increases the working fluid pressure in the other pipe in accordance with the steering angle when the front wheels are steered to the other side, and an input member of the servo valve are integrated. an operating cylinder having a pair of operating chambers for operating in one direction and the other; a return spring for returning the input member to a neutral position; a pair of inlet ports communicating with each of the pipes; and each operating chamber of the operating cylinder. a 4-port 3-position switching valve having a pair of outlet ports communicating with the
The vehicle speed sensor is connected to an oil temperature sensor that detects the temperature of the working fluid supplied to each of the pipes, and if the temperature detected by this oil temperature sensor is higher than a predetermined low temperature, the rear wheels will move to the front wheels at low speeds. The 4-port 3-position switching valve is switched so that the rear wheels are steered in the opposite phase to the front wheels at high speeds, and when the detected temperature is below the low temperature, the rear wheels are steered in the same phase as the front wheels, regardless of the vehicle speed. A rear wheel steering device comprising: a control device that switches the four-port three-position switching valve to a neutral position so that the wheels are not steered.