To fit by the channel of the slit condition which was formed to one side aspect of the lap of the eddying condition which forms the finishing mannered

摘要

PROBLEM TO BE SOLVED: To improve wear resistance in the case of using HFC and HCFC refrigerant as refrigerant gas by using a flat band steel tip seal subjected to plasma nitriding, as a tip seal provided at a spiral lap constituting a fixed scroll or an oscillating scroll. ;SOLUTION: A slit-like groove 31 is formed at one side face of a spiral lap 19 (23) constituting a fixed scroll or an oscillating scroll, and a strip tip seal 33 is fitted into the groove 31 to ensure airtightness of a sliding part. The tip seal 33 to be used is made of high Cr alloy steel containing Cr at 12-15 wt.%, C at 0.6-0.8 wt.% and Fe for the rest, and plasma nitriding is applied thereto. As the condition of this plasma nitriding, it is desirably so set that temperature is 400-550°C, the gas ratio of H₂ gas/NH₃ gas forming an atmosphere is 70-80 vol.%/20-30 vol.% and treatment time is about 3-10 hours. Wear resistance is therefore improved.;COPYRIGHT: (C)1999,JPO