| 摘要 |
PURPOSE:To prevent a decrease of the back pressure by providing a control member which controls the opening angle of a specific bypass port and increases the opening area of a back pressure port feeding the back pressure to vane back sections as the opening angle of this port is increased. CONSTITUTION:As opening angles of bypass ports 23, 23 provided on a front side block 8 having an intake port 16 are increased during the operation, the second notch section 42 of a control member 24 is communicated to a high- pressure chamber 19 side to open back pressure ports 41, 41... feeding the back pressure to backs of vanes 151-154. As a result, the back pressure of the vanes 151-154 is prevented from decreasing and kept constant with respect to the discharge volume of a compressor, and the pressing forces of tips of the vanes 151-154 against the inner periphery of a cam ring 7 are invariably kept constant. Therefore, a occurrence of chattering and loss of power can be prevented. In addition, a sufficient quantity of lubricating oil can be fed to sliding faces between a rotor 10 and both front and rear side blocks 8, 9 when the rotor 10 is rotated at a high speed. |
