| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum pump capable of preventing a damage and a degradation in performance caused by a rotation of a piston against a cam. SOLUTION: A pair of opposed receiving surfaces 36, 37 is provided on the piston in a casing 20. The piston 23 is pressed through the receiving surfaces 36, 37 by an outer periphery part of the cam disposed, rotated and driven between both receiving surfaces 36, 37 to reciprocate it. A suction and an exhaust are carried out by an opening/closing of a suction valve 24 and an exhaust valve 25 communicated with a space 22 in the casing 20 varying the volume accompanying with the reciprocation movement of the piston 23. A first rotation restriction surface 38 positioned at one end side of a pair of receiving surfaces 36, 37 and a second rotation restriction surface 39 positioned at the other end side have curved shapes corresponding to a part of a cylindrical surface along to outer periphery part of the cam 26 such that it contacts with the outer periphery part of the cam 26 when the piston 23 is reciprocated. A rotation around an axis center of the piston 23 against the cam 26 is restricted by contacting the respective rotation restriction surfaces 38, 39 with the outer periphery part of the cam 26. COPYRIGHT: (C)2003,JPO
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