| 摘要 |
PURPOSE:To enable to drive a fluid flow rate control valve with small driving force irrespective of the pressure difference on the opposite sides of the control valve and to make it unnecessary to provide a pressure cancelling mechanism, by dividing a work chamber into four valve chambers by a rotatable valve element, and communicating two pairs of opposite chambers with each other via respective pressure-equalizing passages. CONSTITUTION:A fluid flow rate control valve of this invention is controlled through rotation of a valve element 5 to shift its position continuously from the state that an inlet port 13 and an outlet port 14 are both communicated with one valve chamber 12a to the state that a valve chamber 12d communicated with the inlet port 13 and the valve chamber 12a communicated with the outlet port 14 are isolated from each other. In such a control valve, a first pressure-equalizing passage 13a is formed in the valve element 5 to communicate two chambers 12a, 12b located on the opposite sides of the valve element 5 with each other and to thereby making the pressures in these two chambers equal to each other. Thus, the forces acted to the valve element 5 is balanced. Similarly, a second pressure-equalizing passage 13b is formed in the valve element 5 to equalize the pressures in pressure chambers 12c and 12d and to thereby balance the forces acted to the valve element 5. |
