| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an inexpensive structure capable of easily carrying out tuning for exhibiting stable performance from low-temperature time to high-temperature time. <P>SOLUTION: A plurality of pieces of balls 10 and 10 are arranged between double row outer ring raceways 12a and 12b located in the inner peripheral surface of an outer ring 8 and double row inner ring raceways 13a and 13b located in the outer peripheral surface of a pair of inner rings 9a and 9b for every two rows. These balls 10 and 10 are made of ceramics mainly containing zirconium. By using the zirconium more inexpensive than silicon nitride ceramics and having a small difference in linear expansion coefficient from an iron alloy such as high carbon chromium bearing steel, tuning for exhibiting stable performance from low-temperature time to high-temperature time is easily carried out. Further, affinity between the rolling surfaces of the balls 10 and 10 and lubricant oil is improved to attain lower torque. <P>COPYRIGHT: (C)2012,JPO&INPIT |
