| 摘要 |
PROBLEM TO BE SOLVED: To provide a water pump decreasing the number of part items, and dispersing with closing a hole formed in the case of providing a drain passage, excellent in productivity at a low cost, and provided with a dust infiltration preventing structure. SOLUTION: This water pump comprises a housing 2 having a bearing part 4 fixing a ball bearing 13 supporting a rotary shaft 12 connecting an impeller 11, a vapor passage 17 communicating with an internal space 16 formed between the ball bearing 13 and a mechanical seal 15 to be extended linearly in a diametric direction, and a drain passage 19. Ventilation resistance of the drain passage 19, by inserting it through a rib 8 for a passage extended in the diametric direction outward from an external peripheral surface of the bearing part 4, is made larger than ventilation resistance of the vapor passage 17, so as to suppress infiltration of dust, and a peripheral direction rib 7 is provided in a partial range of a peripheral direction in the upward of only the vapor passage 17, so as to suppress infiltration of dust.
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