| 摘要 |
<p>PURPOSE: To make it possible to obtain desired hysteresis by changing the strength of a compression spring. CONSTITUTION: Within a housing 70 two spools 62, 63 and a spool with a larger diameter are provided and the spools 62, 63 are energized in one direction by springs 68, 69, respectively. In a state where the inlet pressure is low, the inlet 14 and outlet 17 are interlinked and the path 76 and tank 74 are shut off by the larger diameter part 84. When the inlet pressure increases, the spool 62 moves to the right, the larger diameter part 78 of the spool 62 shuts off the outlet 17 and path 77. At this time the inlet 14 and outlet 17 are interconnected by a groove 88. When the inlet pressure further increases, the spool 63 moves to the right, and as the path 76 and tank 74 are interconnected, the spool 67 moves to the right, and the spool 63 moves further to the right, the inlet 14 and outlet 17 are shut off. In this state, the larger diameter 87 of the spool 67 is subject to be pressurized only on the end face with hysteresis being generated.</p> |
