| 摘要 |
PURPOSE:To prevent expansion noise and impact by operating a hydraulic pump when a difference in pressure between both sides of an open-and-close valve to increase pressure on low pressure side, and opening the open-and-close valve when the difference is below the fixed value to operate a hydraulic motor according to an operator's intention. CONSTITUTION:Pressure detectors 8A, 8B are respectively adapted to detect pressure in a circuit connecting between open-and-close valves 4A, 4B and a hydraulic pump 1 and pressure in a circuit connecting between open-and-close valves 4A, 4B and a hydraulic motor 3. A difference in the detected pressure is calculated by a control device 9. When the difference is more than a fixed value, the hydraulic pump 1 is operated to increase pressure in a circuit connecting between the open-and-close valves 4A, 4B and the hydraulic pump 1, and when the difference is below the fixed value or reaches the fixed value, the open-and-close valves 4A, 4B are open. Accordingly, when an operation lever is operated to open the open and close valves 4A, 4B, the hydraulic motor 3 is kept from working against an operator's intention and the generation of expansion noise and impact can be prevented. |
