Antifriction bearing and alternator incorporating same for use in vehicles

Abstract

An antifriction bearing includes a fixed ring which comprises a steel containing up to about 10% of residual austenite. An alternator for vehicles includes a stator mounted on a frame, a rotor having its rotary shaft rotatably supported by a pair of bearings on the frame and a drive pulley mounted on one end of the shaft projecting outward from the frame. The outer ring of at least the bearing toward the pulley comprises a steel containing up to about 10% of residual austenite.

1. An alternator for vehicles comprising a rotary shaft of a rotor which is rotatably supported by a pair of bearings, each comprising a fixed ring and a rotary ring, on a frame having a stator, and a drive pulley which is mounted on one end of the rotary shaft projecting outward from the frame, wherein the alternator comprises at least the bearing directed toward the pulley comprising a fixed ring comprising a steel containing up to about 10% of residual austenite. 
     
     
       2. An alternator as defined in  claim 1  wherein said steel containing limited proportion of austenite has been made by subjecting steel having a higher austenite content to a sub-zero treatment. 
     
     
       3. An alternator as defined in  claim 1  wherein said steel containing limited proportion of austenite has been made by subjecting steel having a higher austenite content to tempering at a temperature of 250° to 380° C. 
     
     
       4. An alternator as defined in  claim 1  wherein said steel containing limited proportion of austenite has been made by subjecting steel having a higher austenite content to a sub-zero treatment and a subsequent tempering treatment at a temperature of 170° to 230° C. 
     
     
       5. An alternator as defined in  claim 1  wherein said steel has been subjected to carburization hardening. 
     
     
       6. An alternator as defined in  claim 1 , wherein the amount of residual austenite is up to 6%. 
     
     
       7. An alternator for vehicles comprising a rotary shaft of a rotor which is rotatably supported by a pair of ball bearings, each comprising a fixed ring and a rotary ring, on a frame having a stator, and a drive pulley which is mounted on one end of the rotary shaft projecting outward from the frame, the fixed ring having a raceway, wherein the alternator comprises at least the bearing directed toward the pulley comprising a fixed ring comprising a bearing steel containing up to about  3 %  of residual austenite at a radial depth of  0 . 1  mm from the raceway of the ring, whereby the rolling fatigue life is improved by preventing occurrence of partial structural changes or minute cracks immediately under the raceway of the fixed ring caused by vibration or impact.   
     
     
       8. An alternator as defined in  claim 7  wherein said steel containing limited proportion of austenite has been made by subjecting steel having a higher austenite content to a sub- zero treatment.   
     
     
       9. An alternator as defined in  claim 7  wherein said steel containing limited proportion of austenite has been made by subjecting steel having a higher austenite content to a sub- zero treatment and a subsequent tempering treatment at a temperature of  170 ° to  230 ° C.