Sealed rolling bearing

Abstract

A sealed rolling bearing is proposed which makes it possible to reduce the torque loss while ensuring high sealing performance. Seal lips of seal members secured to the outer ring of the bearing at both ends thereof are in sliding contact with both ends of the outer periphery of the inner ring of the bearing. These portions of the inner ring that are in sliding contact with the seal lips are subjected to minute shot peening in which minute shots of molybdenum disulfide having a particle diameter of 20 to 200 micrometers are struck against these portions at a high speed of 50 meters per second. This decreases the friction torque attendant to sliding contact of the seal lips and makes it possible to decrease the torque loss of the bearing even if the contact pressure of the seal lips is increased sufficiently to ensure high sealing performance.

1 . A sealed rolling bearing comprising an inner ring, an outer ring, rolling elements disposed between said inner ring and said outer ring, and seal members each having a seal lip and secured to one of said inner and outer rings, said seal lips of said seal members being in sliding contact with metal surfaces which are portions of a surface of the other of said inner and outer rings, or surfaces of members mounted on the other of said inner and outer rings, said metal surfaces being subjected to minute shot peening in which minute shots having a hardness equal to greater than the hardness of said metal surfaces and having a particle diameter of 20 to 200 micrometers are struck against said metal surfaces at a speed of 50 meters per second or over.  
   
   
       2 . The sealed rolling bearing of  claim 1  wherein said minute shots are made of molybdenum disulfide.  
   
   
       3 . The sealed rolling bearing of  claim 1  wherein a raceway of the other of said inner and outer rings is superfinished by grinding after minute shot peening of said metal surfaces.  
   
   
       4 . The sealed rolling bearing of  claim 1  used in a wheel bearing assembly comprising an outer member having two raceways in an inner periphery thereof, an inner member having raceways opposing said respective raceways on said outer member, and a wheel mounting flange provided on one of said outer member and said inner member.