SEAL DEVICE FOR WATER PUMP, ROTATION SUPPORTING DEVICE FOR WATER PUMP AND WATER PUMP

摘要

PROBLEM TO BE SOLVED: To improve durability of a water pump with a structure which does not cost much or increase in size. SOLUTION: A seal device is constituted for preventing a foreign substance from entering a rolling bearing 6a is constituted by combining a seal ring 13 and a slinger 14. A compression amountδof a second seal lip 23 generated when the tip end edge of the second seal lip 23 constituting the seal ring 13 is brought into contact with an outer side of the slinger 14 is set at 1/10 or more and 7/10 or less of the height H of this second seal lip 23 in the free state. Roughness of a portion where the tip end edge of the second seal lip 23 is in sliding contact on the outer side of the slinger 14 is set at 0.2 to 2.0μm in arithmetic mean roughness Ra and 0.8 to 8.0μm in the maximum height Ry.