| 摘要 |
PROBLEM TO BE SOLVED: To make any restriction so as not to be given to the secureness of a signal passage of another system by interconnecting an outlet of the signal passage to a tank in use of a seal groove. SOLUTION: A seal groove 30 surrounding a neutral passage 22 and a return passage 29 is formed on a fixed surface of a valve body 16, and this seal groove 30 and the return passage 29 are interconnected to each other via a clearance groove 31. Then, an interconnecting recess 34 is formed, and thereby the outlet of a signal passage 28 is interconnected to the seal groove 30 via this interconnecting recess 34. Hereat, this interconnecting recess 34 is formed along the axis of a spool so as to make the outlet of the signal passage 28 connect with the seal groove 30 at the shortest distance. In a signal passage mechanism like this, hydraulic fluid is put back to the return passage 29 via those of interconnecting recess 34→seal groove 30→clearance groove 31. Thus, since the seal groove 31 is utilized, length of the interconnecting recess 34 will get off with smallness. Accordingly the secureness of the signal passage of another system with in no case receive any restriction at all.
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