| 摘要 |
PURPOSE:To aim at miniaturization of an oil operating device as well as simplify a countermeasure for sealing by providing the oil operating device in an operating oil passage from a pump to a hydraulic cylinder, and controlling the oil operating device by means of lower pressure oil in another system. CONSTITUTION:In an operating oil passage 110 from a pump 32 to a hydraulic cylinder 10, are provided a first valve body 40 and a pilot valve 80, and then a control oil passage 120, which leads control oil pressure lower than operating oil pressure in the operating oil passage 110 from the pump 32, is connected to the back pressure chamber 86 of the pilot valve 80, and further, an opening/ closing valve 62, which is adapted to intake and exhaust the control oil pressure into and out of the back pressure chamber 86, is disposed via a throttle valve 61 in the control oil passage 120. Therefore, the first valve body 40 is controlled by means of lower pressure oil in another system so as to be miniaturized, so that its decreased sealing surface area simplifies a countermeasure for sealing.
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