Hub-bearing race interface

Abstract

Bearing hubs are typically machined in a lathe. Strict tolerances must be observed because, if the bearing fits too tightly in the hub, it may “lock up” and will not turn. An approach to relax the strict tolerances associated with these bearing hubs is to cut threads or parallel grooves (circumferentially) in the surface in contact with the outer race of the bearing. These threads or the high points between the grooves will deform (crush) when the bearing race is pressed in. The strain, then, in the bearing race is lessened due to the plastic strain of the hub, reducing the chance the bearing will lock up.

We claim:  
     
         1 . A method for relaxing machining tolerances of a bearing hub, the method comprising machining threads into a hub surface in contact with a bearing outer race.  
     
     
         2 . A method for relaxing machining tolerances of a bearing hub, the method comprising machining circumferential grooves in a surface in contact with a bearing outer race.  
     
     
         3 . The method of  claim 1  wherein the threads are made to deform as the bearing outer race is pressed into the hub.  
     
     
         4 . The method of  claim 2  wherein regions between the parallel, circumferential grooves are made to deform as the bearing outer race is pressed into the hub.  
     
     
         5 . An apparatus for relaxing machining tolerances of a bearing hub, the apparatus comprising: 
 (a) the bearing hub; and    (b) threads machined into a surface of the hub in contact with a bearing outer race.    
     
     
         6 . An apparatus for relaxing machining tolerances of a bearing hub, the apparatus comprising: 
 (a) the bearing hub; and    (b) circumferential grooves machined into a surface of the hub and having circumferential ridges between adjacent grooves in contact with a bearing outer race.    
     
     
         7 . The apparatus of  claim 5  wherein the threads are made to deform as the bearing outer race is pressed into the hub.  
     
     
         8 . The apparatus of  claim 6  wherein the ridges between the parallel, circumferential grooves are made to deform as the bearing outer race is pressed into the hub.  
     
     
         9 . An apparatus comprising: 
 (a) an annular bearing hub having threads disposed on an inner surface thereof;    (b) an annular bearing disposed inside of the bearing hub; and    (c) an annular outer race disposed between and in contact with the bearing and the threads of the annular bearing hub whereby the threads will serve as a crush zone and deform if the fit of the outer race between the bearing and the bearing hub is too tight.    
     
     
         10 . An apparatus comprising: 
 (a) an annular bearing hub having annular ridges disposed between adjacent annular grooves on an inner surface thereof;    (b) an annular bearing disposed inside of the bearing hub; and    (c) an annular outer race disposed between and in contact with the bearing and at least some of the ridges of the annular bearing hub whereby the ridges and grooves will serve as a crush zone and deform if the fit of the outer race between the bearing and the bearing hub is too tight.