Rolling bearing and spindle device for machine tools

Abstract

A grease-lubricated rolling bearing has an outer ring having an outer ring race in an inner peripheral surface thereof, an inner ring having an inner ring race on an outer peripheral surface thereof, rolling elements rollably provided between the outer ring race and the inner ring race, and a grease supply element for supplying an additional grease in the rolling bearing. The amount of the additional grease to be supplied at a time is predetermined to be from 0.1 to 4% of the volume of space in the bearing.

1 . A spindle device for a machine tool comprising: 
 a rolling bearing for supporting a spindle, the rolling bearing being mounted in a housing, the rolling bearing being grease-lubricated, the rolling bearing comprising:    an outer ring having an outer ring race in an inner peripheral surface thereof;    an inner ring having an inner ring race in an outer peripheral surface thereof;    rolling elements rollably provided between the outer ring race and the inner ring race;    a grease supplying element for supplying an additional grease in the rolling bearing;    wherein the amount of the additional grease to be supplied at a time is predetermined to be from 0.1 to 4% of the volume of space in the bearing, and    wherein the grease supplying element is a supply hole provided in a housing.    
     
     
         2 . The spindle device according to  claim 1 , wherein the supply hole is radially provided.  
     
     
         3 . The spindle device according to  claim 1 , wherein the supply hole is axially provided.  
     
     
         4 . The spindle device according to  claim 1 , wherein the rolling element is a cylindrical roller.  
     
     
         5 . The spindle device according to  claim 1 , wherein the rolling element is a ball, 
 wherein the ball is disposed between the inner ring race of the inner ring and the outer ring race of the outer ring with a contact angle, and    wherein the supply hole provided in the housing opens at a position apart from a contact area between the ball and the outer ring race.    
     
     
         6 . The spindle device according to  claim 1 , wherein the rolling bearing is used to support a spindle of a machine tool.  
     
     
         7 . The spindle device according to  claim 1 , wherein the diameter of the supply hole is from 0.1 mm to 5 mm.  
     
     
         8 . The spindle device according to  claim 1 , wherein the rolling bearing is used in an operating condition where dmN is not smaller than 1,000,000.  
     
     
         9 . A grease-lubricated rolling bearing comprising: 
 an outer ring having an outer ring race in an inner peripheral surface thereof;    an inner ring having an inner ring race on an outer peripheral surface thereof;    rolling elements rollably provided between the outer ring race and the inner ring race;    a grease supply element for supplying an additional grease in the rolling bearing; and    an outer ring spacer,    wherein the amount of the additional grease to be supplied at a time is predetermined to be from 0.1 to 4% of the volume of space in the bearing,    wherein the grease supplying element is a supply hole provided in the outer ring spacer,    wherein the diameter of the supply hole is from 0.1 mm to 5 mm, and    wherein the rolling elements are cylindrical rollers.    
     
     
         10 . A spindle device for a machine tool comprising: 
 a rolling bearing for supporting a spindle, the rolling bearing being mounted in a housing, the rolling bearing being grease-lubricated, the rolling bearing comprising:    an outer ring having an outer ring race in an inner peripheral surface thereof;    an inner ring having an inner ring race in an outer peripheral surface thereof;    rolling elements rollably provided between the outer ring race and the inner ring race;    a grease supplying element for supplying an additional grease in the rolling bearing; and    an outer ring spacer,    wherein the amount of the additional grease to be supplied at a time is predetermined to be from 0.1 to 4% of the volume of space in the bearing,    wherein the grease supplying element is a supply hole provided in the outer ring spacer,    wherein the diameter of the supply hole is from 0.1 mm to 5 mm, and    wherein the supply hole extends in a radial direction of the rolling bearing.    
     
     
         11 . A spindle device for a machine tool comprising: 
 a rolling bearing for supporting a spindle, the rolling bearing being mounted in a housing, the rolling bearing being grease-lubricated, the rolling bearing comprising:    an outer ring having an outer ring race in an inner peripheral surface thereof;    an inner ring having an inner ring race in an outer peripheral surface thereof;    rolling elements rollably provided between the outer ring race and the inner ring race;    a grease supplying element for supplying an additional grease in the rolling bearing; and    an outer ring spacer,    wherein the amount of the additional grease to be supplied at a time is predetermined to be from 0.1 to 4% of the volume of space in the bearing,    wherein the grease supplying element is a supply hole provided in the outer ring spacer,    wherein the diameter of the supply hole is from 0.1 mm to 5 mm, and    wherein the rolling elements are cylindrical rollers.