| 摘要 |
PURPOSE:To continue the operation of a hydraulic control valve by moving a valve piston even when one side of the hydraulic control valve fails and as well to simplify the structure of thereof, by providing a poppet valve to the valve piston incorporating therein a stationary piston. CONSTITUTION:A stationary piston 23 is incorporated in a valve piston 22, and a poppet valve is disposed therebetween. The valve piston 22 controls hydraulic pressure in an A system by means of a spring 25 and a hydraulic pressure received by the diameter difference (D-d) between the stationary rod 23 and a small diameter part 22a. The large diameter part of the valve piston 22b is subjected to hydraulic pressure in a B system, and is, therefore, moved rightward when the B system fails and has lost hydraulic oil, so that the valve 24 is opened. With this arrangement, hydraulic control may be carried out even when the one hydraulic system fails, without using a balance piston. |
