| 摘要 |
<p>The pump disclosed aims at reducing noises which will be generated at a terminal end of a pump flow passage during rotation of an impeller. The recessed pump flow passage (44) is formed in a casing cover (37), and a damping portion 51 is formed in the terminal end portion of the pump flow passage (44) to extend beyond a discharge port (46). The damping portion (51) is smaller in depth than the pump flow passage (44) and is surrounded by a vertical wall (51a). Further, the damping portion (51) has a slanting wall surface (boundary line) (51c) which permits each vane member of the impeller to enter a partition portion (47) gradually, and is tapered along a rotating direction of the impeller. With this configuration, noises can be reduced, and also, the damping portion (51) can be prevented from deforming even if the casing cover is ground in order to enhance the plane accuracy. Noise reduction can be achieved by the provision of the damping portion which has a depth smaller than that of a main range of the pump flow passage and further extend beyond the discharge port (46), or the provision of the slanting wall surface (boundary line) (51c) in the terminal end of the pump flow passage, which causes each vane member of the impeller to enter the partition portion (47) gradually. <IMAGE></p> |
