| 摘要 |
PROBLEM TO BE SOLVED: To reduce a burden on a workman at the time of greasing operation, prevent a noise such as 'a squeak' generated when a bucket is rotated, and retain a comfortable working environment. SOLUTION: A powder material in which a total of 27weight% of nickel and chrominium is added to a cemented carbide material such as tungsten carbide, is thermally sprayed on both end surfaces 13B, 14C of an arm boss 13 and a bracket 14. Hereby, spray deposits 19, 20 as hard abrasion resistance layers having rigidity are formed on both end surfaces 13B, 14B, and also the surfaces of the spray deposits 19, 20 are formed as uneven surfaces having surface roughness of less than about 30μm. When a bucket is rotated, intervals between the spray deposits 19, 20 are retained under lubrication for a long period by a lubricant such as grease, and abrasive wear, adhesive wear and so on generated between the spray deposits 19, 20 are prevented, and also the grease is prevented from being leaked from the interval between the spray deposits 19, 20 to the outside.
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