OPPOSITE PHASE FOUR-WHEEL STEERING DEVICE WITH LARGE STEERING ANGLE OF FULL HYDRAULIC TYPE

摘要

PURPOSE: To hold the steering angle of rear wheels when an opposite phase four-wheel steering device with large steering angle of full hydraulic type undergoes an oil pressure sink on the over-steering side of a steering wheel. ;CONSTITUTION: An opposite phase four-wheel steering device with large steering angle of full hydraulic type is equipped with an oil path selector valve 10 wherein a rear power cylinder 4 is in series connected with a front power cylinder 3 when steering is made with a large steering angle, and the oil path selector valve connects a cylinder furnished with ports 10a-10f through which a left and a right oil chamber of the front power cylinder and a left and a left and a right oil chamber of the rear power cylinder are connected with the corresponding oil paths on the output side of a control valve 2 to oil paths 44, 45 and ones 42, 43 in the neutral position and during steering with a small steering angle. Oil paths 46, 47 are shut, and the rear power cylinder 4 is in series connected with the return path leading to the control valve 2 from the oil chamber where the oil in the front power cylinder 3 is extruded during steering with a large steering angle, and a spool 12 is provided to connect the oil path of the rear power cylinder parallel with the return path of the front power cylinder at the time of changing over of the oil path from the steering with small steering angle to a large angle, and vice versa.;COPYRIGHT: (C)1994,JPO&Japio