To reduce a manufacturing cost by improving yield of a shaft material, preventing air leakage from a fitting portion of a mechanical seal, reducing weight and facilitating assembling operation.
A bearing for a water pump is prepared by arranging a rolling body with a spacing between a shaft 1 composed of a big shaft part 1a commonly used for an inner ring and a small shaft to which a mechanical seal and an impeller are press-fitted, and an outer ring fitted to a housing 2. The shaft 1 is prepared by independently manufacturing a big shaft 2 and a small shaft 3 press-fitting or welding the small shaft 3 to the big shaft 2. The shaft is prepared by press-fitting or welding the small shaft 3 to the big shaft 2 and injection-molding synthetic resin to a portion around a support core bar.
SAKATA YOSHIZUMI
MASUDA NAOKI
