To provide a hydraulic unit capable of purifying a working oil by positively filtering foreign matter in a return oil and preventing a hydraulic pump from being damaged by the foreign matter even when a seal of a hydraulic actuator is damaged and a large amount of foreign matter intrudes into the return oil, or when a safety valve is opened due to surge pressure.
An upstream side filter 15 and a downstream side filter 16 are arranged in series in a flow passage of the return oil from the hydraulic actuator such as a hydraulic cylinder 14 in the hydraulic unit, differential pressure before and after of the upstream side filter 15 arranged on the upstream side is measured with a differential pressure gauge 15b, and an alarm generating means 20 is provided for generating an alarm from an alarm generator 15e when the measured differential pressure reaches a reference value.
| WO/2009/035945 | PRESSURE-COMPENSATED ACCUMULATOR BOTTLE |
| WO/2018/131118 | FAN DRIVE SYSTEM AND MANAGEMENT SYSTEM |
MATSUZAWA NOBUHIRO
IWAKURA AKIRA
| JPH02170049A | 1990-06-29 | |||
| JPS61119610A | 1986-06-06 |
Yoshihiko Kido