| 摘要 |
PURPOSE:To prevent defective operation of a valve body by a method wherein a mechanism to change a clearance between a rotary valve body and a valve seat through relative movement of the two members is provided, and the clearance is set to a high value in a place in the vicinity of a position where the rotary valve body is fully opened and a low value in a place in the vicinity of a position where it is fully closed. CONSTITUTION:A flow rate control valve is located in the middle of a bypass intake air passage 8 connected to an intake air passage in a manner to bypass the throttle valve of an internal combustion engine. The flow rate control valve causes a permanent magnet 3 to generate a rotation force through energization to a solenoid 1, and rotates a rotary valve 5 through a shaft 4 to a position where it is balanced with a rotation force in a reverse direction generated through the force of a return spring 13. In this case, a valve seat 9 positioned facing the rotary valve 5 is moved forward and backward by means of a temperature-sensitive member 11 with which a variable clearance mechanism is formed. The temperature-sensitive member 11 is formed to an annular base sheet 11a, formed in a manner to surround the outer periphery of a passage element 8b, such that a plurality of bimetal pieces 11b are cut and risen axially of the base sheet 11a, and is changed in a state to be expanded and contracted according to the temperature of cooling water in a cooling water passage 12. |
