Patent ID: 7398648
Filing Date: 2008-07-15
Classification: B60W,F15B,F16H

Abstract:
1. A travel control device for a hydraulically driven vehicle, comprising: hydraulic pump driven by a prime mover; a target rotation speed command device that issues a command for a target rotation speed of the prime mover; a traveling motor driven with pressure oil delivered from the hydraulic pump; a control valve for traveling that controls a flow rate of the pressure oil delivered from the hydraulic pump to the traveling motor; a counterbalance valve switched in response to a motor load pressure supplied via the control valve, that generates a braking pressure at a conduit disposed on a return side of the traveling motor as the load pressure becomes lower; a rotation speed detection device that detects a rotation speed of the traveling motor; an overspeed detection device that detects an overspeed state in the traveling motor if the motor rotation speed detected by the rotation speed detection device is equal to or greater than a predetermined value; and a motor overspeed inhibiting device that inhibits rotation of the traveling motor, if the overspeed detection device detects an overspeed state in the traveling motor and a command value issued from the target rotation speed command device is to or greater than a predetermined value, until a braking pressure is generated through a switchover at the counterbalance valve and the traveling motor is no longer in the overspeed state.