Seal apparatus for a water pump, rotation-support apparatus for a water pump, and a water pump

A rotation-support apparatus for a water pump comprising:

• an outer ring having an inner peripheral surface formed with an outer ring raceway, a rotating shaft for the water pump having an outer peripheral surface formed with an inner ring raceway, a plurality of rolling elements rotatably located between the outer-ring raceway and inner-ring raceway, a seal ring having an outer peripheral edge fastened to the inner peripheral surface of the outer ring at one end thereof, and a singer having a side surface and fitted around the rotating shaft, the seal ring having a first seal lip that comes in sliding contact with the outer peripheral surface of the rotating shaft or with the outer peripheral surface of a portion that rotates together with the rotating shaft, and a second seal lip that has a tip edge which comes in sliding contact with the side surface of the singer, and that is tilted outward in the radial direction toward the tip edge thereof, wherein the amount of compression of the second seal lip, which occurs when the tip edge of the second seal lip comes in contact with the side surface of the singer, is at least {fraction (1/10)} and up to {fraction (7/10)} the height of the second seal lip in a free state, and the roughness of a side surface portion of the singer with which the tip edge of the second seal lip comes in sliding contact is from 0.2 μm to 2.0 μm in the arithmetic mean Ra, or is from 0.8 μm to 8.0 μm in the maximum height Ry.

A water pump comprising a housing having an inner peripheral surface;

• an outer-ring raceway that is formed directly around the inner peripheral surface of this housing or formed around a separate outer ring around the inner peripheral surface of this housing, a rotating shaft having an outer peripheral surface formed with an inner-ring raceway, a plurality of rolling elements rotatably located between the outer-ring raceway and inner-ring raceway, a seal ring having an outer peripheral edge fastened to the inner peripheral surface of the outer ring at one end thereof, a singer having a side surface and fitted around the rotating shaft, a pulley fastened to the rotating shaft at an outer end thereof, an impeller fastened to the rotating shaft at an inner end thereof, a mechanical seal provided between the inner peripheral surface of the housing and the outer peripheral surface of the rotating shaft and axially between the impeller and the singer, and a space provided axially between the mechanical seal and the seal ring, the seal ring comprising a first seal lip that comes in sliding contact with the outer peripheral surface of the rotating shaft or with the outer peripheral surface of a portion that rotates together with the rotating shaft, and a second seal lip that has a tip edge which comes in sliding contact with the side surface of the singer, and that is tilted outward in the radial direction toward the tip edge thereof, wherein the amount of compression of the second seal lip, which occurs when the tip edge of the second seal lip comes in contact with the side surface of the singer, is at least {fraction (1/10)} and up to {fraction (7/10)} the height of the second seal lip in a free state, and the roughness of a side surface portion of the singer with which where the tip edge of the second seal lip comes in sliding contact is from 0.2 μm to 2.0 μm in the arithmetic mean Ra, or is from 0.8 μm to 8.0 μm in the maximum height Ry.