| 摘要 |
PURPOSE:To obtain an inlet control device having a less energy loss, by making the discharge pressure of the inlet control device affect upon a control member with the use of a change-over valve when the discharge pressure is below a set pressure. CONSTITUTION:Two hydraulic pumps 3a, 3b are driven by a single motor 1. Change-over valves 12a, 12b are disposed between pressure reducing valves 11b, 11a in a control circuit and control members 4a, 4b in cylinder chambers 10a, 10b. The set pressures of these change-over valves 12a, 12b are slightly lower than the set pressures of relief valves 30a, 30b. Either one of the change-over valves 12a, 12b make the discharge pressure of a pump 3b belonging to the other change-over valve affect upon the cylinder chamber 10a when the discharge pressure of a pump 3a belonging to itself is below a set value. In this case the control is made as usual. When the discharge pressure exceeds a set value, the change-over valve 12a make the discharge pressure of the pump 3a belonging itself affect upon the cylinder chamber 10a to reduce its discharge flow. The same steps are taken for another pump 3b. |
