| 摘要 |
PURPOSE:To improve safety of the device in such a way that a relief valve which is opened when pressure in the pressure chamber goes up beyond the determined maximum value is inserted into a path which links the side of a pressure chamber and a reservoir chamber in an electromagnetic pump to actuate an actuator. CONSTITUTION:When pressure on the side of a pressure chamber 17 abnormally goes up through clogging of an orifice 20, a relief valve 21 which is connected in parallel with the orifice 20 is opened, and working oil on the side of the pressure chamber 17 is returned through the relief valve 21 to a reservoir chamber 14. In consequence, if the pressure which is opened by means of the relief valve 21 is set to its proper value, the pressure on the side of the pressure chamber 17 may not abnormally go up, and when an electromagnetic pump 13 comes to a stop, a bypass valve 24 is opened forthwith, and opening of pressure on the side of the is done momentarily. |
