| 摘要 |
[Problem] To permit guiding oil of a high pressure in an oil passage section, which communicates a valve device and a filter to each other, to a relief valve by a relatively inexpensive structure even when clogging occurs in a filter arranged in an oil passage communicating the valve device and the relief valve to each other. [Solution] A hydraulic pump (20) and a charge valve (25), to which pressure oil is fed from the hydraulic pump (20) via an oil passage (26), are arranged. Arranged in the charge valve (25) are a valve device, for example, an on/off valve (33) switchable according to pressure oil delivered from the hydraulic pump (20), a relief valve (34) specifying a maximum of switching pressure for the on/off valve (33), and a filter (36) arranged in an oil passage (35) communicating the on/off valve (33) and the relief valve (34) to each other. In the oil passage (35), a check valve (37) is arranged in parallel with the filter (36) such that a flow of pressure oil from a side of the on/off valve (33) toward a side of the relief valve (34) is allowed but a flow of pressure oil from the side of the relief valve (34) toward the side of the on/off valve (33) is prevented. |
