| 摘要 |
PURPOSE: To protect a housing chamber from respiring movement by connecting the housing chamber with a pressure-relief valve unit through a joining unit. CONSTITUTION: A valve unit 11 is put at connection paths 8 and 12 between a pressure storage unit 13 and a pressure load 9. The valve unit 11 has a pressure relief unit 10 opened to atmosphere. The valve unit 11 is controllable for moving to two positions. Then, the pressure load 9 is connected to the pressure storing unit 13 at the first position, while the pressure load 9 is joined to the pressure relief unit 10 at the second position. At the second position, even when a pressure medium flows from the pressure load 9 to the pressure relief unit 10 generating positive pressure, the pressure does not propagate to the housing chamber 3, because of a joining unit 6 that functions as a throttle in the volume of the pressure medium. Even when the atmosphere is humid, the humidity does not reach the housing chamber 3, because the humidity is condensed inside the pressure relief unit 10 or the joining unit 6. As a result, the infiltration of humidity is prevented, and the reliability in the control unit is improved. |
