| 摘要 |
PROBLEM TO BE SOLVED: To provide a pulley for a belt type CVT superior in abrasion resistance, which inhibits the lowering of the surface hardness due to a repeating load with a high surface pressure accompanied by sliding and due to heat generated by the sliding, and abrasion accompanied by a fatigue crack, on a sliding surface on which a metal belt slides. SOLUTION: The pulley 2 for the belt type CVT has a sliding surface 21 which slides with a belt 3, in a belt type continuously-variable transmission (belt type CVT) 1, and is manufactured by using a chromium steel or a chromium molybdenum steel specified in JIS G 4053, as a steel of a base material. The sliding surface 21 has a surface roughness Ra (μm) of 0.8μm or less, and has a surface hardness H (Hv) in such a range as to satisfy (surface hardness H)≥500 (surface roughness Ra)+650. The average amount of retained austenite existing in a depth of 20 to 30μm from the sliding surface 21 is 15 to 40%. The pulley satisfies at least one of following conditions: the surface roughness Ra of the sliding surface 21 is 0.3μm or less; and the amount of the retained austenite on the top surface is 10% or less. COPYRIGHT: (C)2009,JPO&INPIT
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