Wheel support bearing assembly

Abstract

To provide a wheel support bearing assembly in which the frictional resistance can be effectively reduced while effects of minimizing leakage of the filled lubricant and ingress of dust and muddy water from outside of the bearing assembly are secured, the wheel support bearing assembly includes an outer member 1 , an inner member 2 positioned inside the outer member 1 with an annular working space defined between it and the outer member 1 , and rows of rolling elements 3 accommodated within the annular working space and rollingly received in part within outer raceways 4 in the outer member 1 and in part within inner raceways 5 in the inner member 2 . Opposite open ends of the annular working space are sealed by respective sealing members 7 and 8 which are secured to one of the outer and inner members 1 and 2 . Each of those sealing members 7 an 8 has a plurality of elastic sealing lips 10 a to 10 c or 12 a to 12 c having their free ends oriented towards associated sealing surfaces 2 c defined on the other of the outer and inner members 1 and 2 , or 15 aa and 15 ba defined on a sealing contact member 15 secured to the other of the outer and inner members 1 and 2 . Of those elastic sealing lips, the axially innermost sealing lips 10 a and 12 a function as a non-contact sealing lip that defines a respective gap of a size δ1 and δ2 sufficient to provide a non-contact sealing effect. The remaining sealing lips 10 b , 10 c , 12 b and 12 c function as a contact sealing lip.

1 . A wheel support bearing assembly, comprising:
 inner and outer members defining an annular working space therebetween, and accommodating lubricated rolling elements within the annular working space, one of the inner and outer members being stationary and the other being rotational; and   a sealing member fitted to the stationary member and sealing an open end of the annular working space, the sealing member having a unitary elastic member with first to third elastic sealing lips, wherein   the first elastic sealing lip forming an axially innermost elastic sealing lip defines a single circumference thereof, extending axially inwardly of the annular working space, and defines a gap between an end thereof and a sealing surface defined on the rotational member or on a sealing contact member fitted to the rotational member, the gap being sized to permit flow of air therethrough and to provide a non-contact sealing effect during relative rotation between the stationary and rotational members, and wherein,   the second and third elastic sealing lips are disposed axially outwardly of the first elastic members to form sliding contact with the sealing surface.   
   
   
       2 . The wheel support bearing assembly as claimed in  claim 1 , wherein the sealing member includes a core metal and an elastic member rigidly mounted on the core metal. 
   
   
       3 . The wheel support bearing assembly as claimed in  claim 1 , wherein the gap is defined in a radial direction between a free end face of the first elastic sealing lip and the sealing surface. 
   
   
       4 . The wheel support bearing assembly as claimed in  claim 1 , wherein the free end face of the first elastic sealing lip which confronts the sealing surface has a width, as measured in a direction across a thickness of the first elastic sealing lip, which is greater than that of the second and third elastic sealing lips. 
   
   
       5 . The wheel support bearing assembly as claimed in  claim 1 , wherein the sealing contact member includes a cylindrical wall and an radially upright wall protruding radially outwardly from the cylindrical wall so as to render the sealing contact member to represent a generally L-sectioned configuration, and wherein the first elastic sealing lip confronts a first portion of the sealing surface defined on an outer peripheral surface of the cylindrical wall and at least one of the second and third elastic sealing lips is held in sliding contact with a second portion of the sealing surface defined on the radially upright wall that confronts the sealing member. 
   
   
       6 . The wheel support bearing assembly as claimed in  claim 1 , further comprising a ring-shaped multi-pole magnet secured to the sealing contact member, said multi-pole magnet magnetized to have a plurality of opposite magnetic poles alternating with each other in a direction circumferentially thereof. 
   
   
       7 . The wheel support bearing assembly as claimed in  claim 1 , wherein the inner member is rotational and has one end formed with a flange which extends radially outwardly beyond a level of an outer periphery of a cylindrical portion of the outer member and wherein the sealing member is used to seal one of the opposite open ends of the annular working space adjacent such flange.