| 摘要 |
PURPOSE:To prevent breakdown of a charge pump by connecting an assist pump system of simple construction to a discharging side of the charge pump system and rising pressure when an oil pressure of the charge pump system is dropped in reversing of a main shaft. CONSTITUTION:When a main shaft is rotated positively, a charge pump 13 is rotated positively and absorbs control oil from a suction port and discharges from a discharging port. When the main shaft is rotated reversely, the charge pump 13 is also made to rotate reversely, and the discharging side of a charge pump system 14 is made to low pressure due to suction from the discharging port. Then an assist pump system 24 is provided and working oil is supplied from this pump system 24, and the pressure of the discharging side of the charge pump system 14 is risen. Then, seizure of the charge pump due to generation of cavitation and oil lack can be prevented. |
