Wheel bearing apparatus for a vehicle

摘要

A vehicle wheel bearing apparatus has an outer member, an inner member, double row rolling elements, and seals. At least one seal of the seals has a metal core press-formed from steel sheet with a cylindrical fitting portion. A radial portion extends radially inward from the end of the fitting portion. A sealing member with a plurality of sealing lips is integrally adhered to the fitting portion of the metal core. Bearing grease is contained within the bearing. Sealing grease is applied to the sealing lips. Both the bearing grease and the sealing grease use the same thickener and the worked penetration of 350 or less. The kinematic viscosity of the base oil of the sealing grease at 40° C. is set to 70% or less of the kinematic viscosity of the base oil of the bearing grease at 40° C.

主权项

1. A vehicle wheel bearing apparatus comprising:
an outer member formed with double row outer raceway surfaces on an inner circumference of the outer member; an inner member including a wheel hub and at least one inner ring, the wheel hub is integrally formed on one end with a wheel mounting flange, a cylindrical portion axially extends from the wheel mounting flange, the inner ring is press-fit onto the cylindrical portion of the wheel hub, and double row inner raceway surfaces are formed on outer circumferences of the wheel hub and the inner ring, the inner raceway surfaces oppose, respectively, the double row outer raceway surfaces; double row rolling elements are freely rollably contained between the inner raceway surfaces of the inner member and the outer raceway surfaces of the outer member; seals are mounted within annular openings formed between the outer member and the inner member; at least one seal of the seals includes a metal core press-formed from a steel sheet with a cylindrical fitting portion and a radial portion, the cylindrical fitting portion is adapted to be press-fit into the inner circumference of an end of the outer member, via a predetermined interference, the radial portion extends radially inward from the end of the outer member; a sealing member of synthetic rubber is formed with a plurality of sealing lips, the sealing member is integrally adhered to the fitting portion of the metal core by vulcanizing adhesion; bearing grease is contained within the vehicle wheel bearing apparatus in a sealed manner, sealing grease is applied to sliding portions of the sealing lips, both the bearing grease and the sealing grease use a same thickener and a worked penetration of 350 or less; and kinematic viscosity of base oil of the sealing grease at 40° C. is set to 70% or less of that of the bearing grease at 40° C. to reduce the rotational torque of the seals of the wheel bearing apparatus.