Seal structure for relatively rotational members

Abstract

A seal structure is disclosed as mounted in a coupling 1, exposed in the vicinity of a stationary member 14, with a dust cover 15 being mounted to a cylindrical member 19 for preventing foreign material from entering a gap between the coupling 1 and the stationary member 14, and a seal member 17 is disposed at a position opposed to the dust cover on the stationary member 14, with a seal portion 123 of the seal 17 being held in sliding contact with the dust cover 15.

1 . A seal structure, separated from a race portion of a bearing structure, for sealing a gap between a first member and a second member disposed to be rotational relative to the first member, the seal structure comprising: 
 a cover member preventing foreign material from entering the gap; and    a seal member fixedly secured to at least one of the first and second members and held in sliding contact with the cover member to seal the gap,    wherein the seal member is held in sliding contact with a sliding surface of the other of the first and second members and the sliding surface is formed with hard material.    
   
   
       2 . The seal structure according to  claim 1 , wherein the first member has a bent portion positioning the bearing structure from a direction opposite to the seal member.  
   
   
       3 . The seal structure according to  claim 1 , wherein a distance between a fixed surface of the seal member and a center of a rotational axis of the second member is smaller than a distance between an outer diametrical surface of the bearing structure and the center of the rotational axis of the second member.  
   
   
       4 . A seal structure for sealing a gap between a first member and a second member disposed to be rotational relative to the first member, the seal structure comprising: 
 a cover member preventing foreign material from entering the gap; and    a seal member fixedly secured to at least one of the first and second members, disposed between the cover member and a bearing, and held in sliding contact with a sliding surface of the other of the first and second members,    wherein a distance between a fixed surface of the seal member and a center of a rotational axis of the second member is smaller than a distance between an outer diametrical surface of the bearing and the center of the rotational axis of the second member.    
   
   
       5 . The seal structure according to  claim 4 , wherein the sliding surface is formed with hard material.  
   
   
       6 . The seal structure according to  claim 4 , wherein the sliding surface is subjected to a surface hardening treatment.  
   
   
       7 . The seal structure according to  claim 4 , wherein the first member has a bent portion positioning the bearing from a direction opposite to the seal member.  
   
   
       8 . The seal structure according to  claim 7 , wherein the bent portion has an inner periphery surface fixed with the seal member and an end surface fixedly secured to the bearing.  
   
   
       9 . The seal structure according to  claim 4 , wherein the seal member has a sliding radius of curvature smaller than a rotating radius of curvature of the bearing.  
   
   
       10 . The seal structure according to  claim 4 , the seal member is provided in an area close to the bearing.  
   
   
       11 . The seal structure according to  claim 4 , wherein the cover member has a bending portion extending along the rotational axis of the second member.