| 摘要 |
It is an object of a rotation support apparatus for a turbocharger according to the present invention to realize a structure which not only can control an increase in the cost thereof but also can secure the excellent durability thereof. In the rotation support apparatus for a turbocharger of the present invention, of first and second ball bearings 4 and 5 for supporting a rotary shaft 3 with an impeller and a turbine respectively fixed to the two end portions thereof, the second ball bearing 5, which is exposed to a strict lubricating condition and is disposed on the turbine side, is improved in the durability. For this purpose, the contact angle of the second ball bearing 5 is set in the range of 5 - 25 DEG . Also, of the composing parts of the second ball bearing 5, at least one of the surface of a second inner raceway 12 formed in the outer peripheral surface of a second inner ring 13 and the rolling surfaces of second balls 14, 14 is or are nitrided to thereby form a nitrided surface or nitrided surfaces thereon. <IMAGE> |
