Patent ID: 7621124

Claim:
A travel vibration suppressing device disposed in a working vehicle, the travel vibration suppressing device absorbing a pressure pulsation generated in an actuator when the working vehicle is traveling, and comprising: a hydraulic pump; at least one actuator having a pressure chamber and being actuated by pressure oil discharged from the hydraulic pump; an accumulator connected to the pressure chamber in the at least one actuator for absorbing a pressure pulsation generated in the pressure chamber; a directional control valve for controlling a supply and a discharge of the pressure oil to the at least one actuator; and a ride control valve for switching a communicating state and a cutout state between the accumulator and the pressure chamber, the cutout state being a state in which flow of pressure oil through the ride control valve to and from the accumulator and the pressure chamber is prevented, wherein the ride control valve is located in a ride valve body, the directional control valve is located in a directional control valve body, the ride valve body is disposed on the directional control valve body in a laminated manner, the ride control valve and the directional control valve are connected through an internal piping in the ride valve body and the directional control valve body, the travel vibration suppressing device comprises a first pressure sensor for detecting a load pressure of the at least one actuator, a communication opening area of the ride control valve which communicates between the accumulator and the pressure chamber is controlled on a basis of a detected signal from the first pressure sensor, and the communication opening area is relatively small when a load pressure detected by the first pressure sensor is a relatively high load pressure and the communication opening area is relatively large when a load pressure detected by the first pressure sensor is a relatively low load pressure.