| 摘要 |
PROBLEM TO BE SOLVED: To prevent an intake portion of a cam ring from cracking, by forming a chamfer in both edges of an inner wall of each intake portion of the cam ring in a vane pump in which a pair of discharge portions and a pair of intake portions are symmetrically disposed with respect to a rotation axis of a rotor. SOLUTION: In a cam ring 4, each of a pair of intake corner portions c1 has a chamfer 15 in both edges of an inner wall of a portion adjacent to an arc portion b. Thus, even if pulling force as shown by the arrow f is applied, stress is dispersed. Accordingly, the stress does not concentrate at a specific portion, thereby effectively preventing an intake portion of the cam ring 4 from cracking. When a certain vane is located at the chamfer 15 during rotation, chambers located on both sides of the vane momentarily communicate with each other. However, since these chambers are essentially at a low pressure, such communication does not hinder the function as a vane pump.
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