JPH0459575U - - Google Patents

Description

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the four-wheel steering system of the present invention, which corresponds to the invention described in claim 1. FIG. 1 is a partial cross-sectional plan view showing the overall configuration, and FIG. The figure is an enlarged view of part A in Figure 1, Figure 3 is a diagram showing the relationship between the displacement amount in the axial direction of the rear wheel output shaft and the spring load applied in the axial direction of the rear wheel output shaft, and Figure 4
FIG. 5 is a diagram showing the relationship between vehicle speed and steering angle ratio; FIG. 5 is a sectional view showing a second embodiment of the four-wheel steering system of the present invention, The figure is a sectional view showing a third embodiment of the four-wheel steering system of the present invention, which corresponds to the invention set forth in claim 2. 1... Steering wheel, 2... Steering shaft, 3... Steering gear, 4...
Front wheel output shaft, 5... Knuckle arm, 6... Front wheel, 7... Steering column, 8... Steering angle sensor, 9... Rear wheel, 10... Housing, 11...
Rear wheel output shaft, 12... Force application point, 13... Knuckle arm, 14... Steering center, 15... Rack tooth, 16... Transmission shaft, 17... Pinion tooth, 18...
... Worm wheel, 19 ... Electric motor, 20
... Output shaft, 21 ... Worm, 22 ... Displacement sensor, 23 ... Vehicle speed sensor, 24 ... Controller, 2
5...Centering spring, 26...Seat plate,
27...Stepped portion, 28...Stop spring, 29...
... disc spring, 31 ... electromagnetic clutch, 32 ... rotation angle sensor, 33, 34 ... viscous damper, 35 ...
... Cylinder part, 36 ... Piston part, 37 ... Supply and discharge port, 38 ... Oil feed pipe, 39 ... Flow rate adjustment valve, 4
0...Solenoid, 41...Aperture nozzle.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A steering angle sensor that detects the steering angle applied to the front wheels, a rear wheel output shaft that applies a steering angle to the rear wheels by displacing in the axial direction, and An electric motor that displaces a wheel output shaft in the axial direction, a vehicle speed sensor that detects vehicle speed, and a clutch that is provided between the rotary drive shaft of the electric motor and the rear wheel output shaft and that electrically connects and disconnects. and a displacement sensor that detects a steering angle applied to the rear wheels based on the displacement of the rear wheel output shaft, and energizing the electric motor based on signals from the steering angle sensor and the vehicle speed sensor. a controller for controlling engagement and disengagement of the clutch, the steering center of the rear wheels is positioned rearward in the forward direction of the vehicle from the force application point of the rear wheels, and the output shaft for the rear wheels is positioned relative to the vehicle body. , is elastically supported so as to be slightly displaceable in the axial direction, and the controller connects the clutch and controls the electric motor to operate only when the vehicle speed detected by the vehicle speed sensor is below a certain value. The steering angle can be freely applied to the rear wheels based on energization, and when an abnormality is detected by the signals from each of the sensors and the vehicle speed is below a certain value, the clutch remains engaged, A four-wheel steering device in which the clutch is disconnected after the rear wheel output shaft is slowly moved toward a neutral position by an electric motor. (2) A steering angle sensor that detects the steering angle applied to the front wheels, a rear wheel output shaft that applies the steering angle to the rear wheels by displacing in the axial direction, and a steering angle sensor that detects the steering angle applied to the front wheels; an electric motor for displacing the vehicle, a vehicle speed sensor for detecting vehicle speed, a clutch that is provided between the rotary drive shaft of the electric motor and the output shaft for the rear wheels and electrically connects and disconnects the output shaft for the rear wheels; a displacement sensor that detects a steering angle applied to the rear wheels based on the displacement of the rear wheels, and controls energization of the electric motor and connection/disconnection of the clutch based on signals from the steering angle sensor and the vehicle speed sensor. It has a controller and a damper mechanism that acts as a resistance against displacement of the rear wheel output shaft in the axial direction, and the steering center of the rear wheel is positioned rearward in the forward direction of the vehicle from the point of application of the rear wheel. and the output shaft for the rear wheels is elastically supported with respect to the vehicle body so as to be freely slightly displaced in the axial direction, and the controller is configured to control the output shaft when the vehicle speed detected by the vehicle speed sensor is below a certain value. The clutch is engaged only when the steering angle is freely applied to the rear wheels based on the energization of the electric motor, and when an abnormality is detected by the signals from each of the sensors and the vehicle speed is below a certain value. A four-wheel steering system in which the clutch is immediately disconnected when the clutch is in use.