Drive controlling mechanism

摘要

A drive controlling mechanism comprises an operative block assembly securely connected with a motor housing accommodating therein a hydraulic motor and rotatably receiving a rotary shaft of the hydraulic motor; a parking brake arrangement connected with the operative block assembly to brake and release a rotary shaft; a control valve arrangement provided to control of the hydraulic motor and actuation of the parking brake arrangement; a pair of inlet-outlet passages connecting the actuation ports of the hydraulic motor and the control valve arrangement; a control conduit arrangement having a shuttle valve permitting fluid under pressure to be introduced into the parking brake arrangement from the control valve arrangement and to be discharged from the parking brake arrangement; and a drain passage arrangement for discharging fluid under pressure from the parking brake arrangement through the shuttle valve to a drain chamber defined between the motor housing and the hydraulic motor.