| 摘要 |
The pump output is governed by means of an electrical control system which compares a signal from an output pressure sensor to a reference value and controls a pair of proportional valves accordingly. The proportional valves (15,16) supply hydraulic pressure for two different functions, such as a motor drive (13) and a cylinder (14), from the pump (10). Electro-magnets (19,20,21,22), controlled from the control system (25), set the valve slide positions each way from their centre positions. A change-over valve (26) is operated by load demand from the two users (13,14) and controls the valve (30) which, in turn, causes the pump (10) to supply the maximum pressure required. A pressure sensor (35) feeds back a signal to the control system to ensure adequate pump pressure for the demand.
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