| 摘要 |
PURPOSE:To prevent the production of noises and the abrasion of the side-sealing material in a vane-type air pump to supply the secondary air for the purification of the engine exhaust gas by making the air-shutting up starting line bysymmetric, and providing a buffer chamber directly before the starting line. CONSTITUTION:In order to make the position where the air-shutting up is started bysymmetric with respect to the center of a cylinder 6, an air-shutting up starting line 50 is formed in parallel with the axis of the cylinder 6. A buffer chamber 73 provided directly before the starting line 50 permits fluid to be once shut up when a vane 10 passes a lip 72. When the vane 10 reaches the buffer chamber 73 a portion of the fluid escapes to a suction chamber 2, and so the fullscale shutting up is started when the vane 10 has reached the starting line 50. This prevents the production of noises due to a sudden air-shutting up. In addition, since the air-shutting up is successively performed bysymmetrically with respect to the vane 10, the abrasion of the side-sealing material due to the load axially displacing the vane 10 can be prevented. |
