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 having an outer peripheral edge fastened to the inner peripheral surface of the outer ring at one end thereof, and a slinger having an outer peripheral surface and fitted around the rotating shaft, the slinger having an outer peripheral edge formed with an outer-diameter-side cylindrical section which is concentric with the rotating shaft and has an outer peripheral surface, the seal ring comprising a first seal lip that comes in sliding contact with the outer peripheral surface of the slinger that rotates together with the rotating shaft, a second seal lip that has a tip edge which comes in sliding contact with the outer peripheral surface of the outer-diameter-side cylindrical section, and that is tilted inward in the radial direction toward the tip edge thereof, wherein the amount of elastic deformation of the second seal lip, which occurs when the tip edge of the second seal lip comes in contact with the outer peripheral surface of the outer-diameter-side cylindrical section, 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 section of the outer peripheral surface of the outer-diameter-side cylindrical section 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, and a third seal lip coming in sliding contact with the outer peripheral surface of the slinger.

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 slinger having an outer peripheral 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 slinger, and a space provided axially between the mechanical seal and the seal ring, the slinger having an outer peripheral edge formed with an outer-diameter-side cylindrical section which is concentric with the rotating shaft and has an outer peripheral surface, the seal ring comprising a first seal lip that comes in sliding contact with the outer peripheral surface of the slinger that rotates together with the rotating shaft, a second seal lip that has a tip edge which comes into sliding contact with the outer peripheral surface of the outer-diameter-side cylindrical section, and that is tilted inward in the radial direction toward the tip edge, wherein the amount of elastic deformation of the second seal lip, which occurs when the tip edge of the second seal lip comes in contact with the outer peripheral surface of the outer-diameter-side cylindrical section, 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 section of the outer peripheral surface of the outer-diameter-side cylindrical section 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, and a third seal lip coming in sliding contact with the outer peripheral surface of the slinger.