| 摘要 |
PURPOSE:To prevent the area of a variable area orifice from increasing at the rise of load pressure by a structure wherein a partition wall with a through hole forming the variable area orifice is built in a sleeve responding to the pressure of working oil, which is sent from a by-pass port back to the suction side of a pump. CONSTITUTION:The orifice sleeve 20 equipped with the partition wall 9 is slidably inserted in the cylinder bore 21 of a valve body. A pressure receiving collar part 22, which senses the pressures in the right and the left pressure chambers 23 and 24 of the cylinder bore 21, is formed on the sleeve 20. The one pressure chamber 23 is connected through a through hole 26 and a passage 27 to a passage 31 for sucking working oil from a reservoir to the pump, while the other pressure chamber 24 is communicated through a passage hole 31 and a passage 32 to a return passage 33, which is connected to a by-pass port 3. On the other hand, the tip swollen diametral part 8 of a drooping pin 7 is inserted in the through hole 10 provided on said partition wall 9, resulting in forming the variable area orifice 11 to control the flow rate of a supply port 4. The pin 7 is connected to a spool 6, which receives the pressure before and after the orifice 11. |
