| 摘要 |
PROBLEM TO BE SOLVED: To improve fastening strength of a plastic fastening part by mutually fastening divided pieces accurately by the plastic fastening part without requiring a post process. SOLUTION: A built-up type crankshaft 1 is built up as one body by mutually assembling a plurality of divided pieces 2A-2I by the plastic fastening parts 3. The plastic fastening part 3 includes building hole parts 8 formed on one sides of the adjacent divided pieces 2A-2I, and building shaft parts 6 formed on other sides. Plastic fastening is carried out by pressing the building shaft part 6 into the building hole part and assembling the same. A plurality of balls 11 disposed on an inner side of an outer diameter of the building shaft part 6 are provided at a tip end outer circumference of the building shaft part 6. Serration 7 is formed on an outer circumference of the building shaft part 6. A groove part 13 in which each ball 11 is fitted when the building hole part 8 is assembled to the building shaft part 6, is formed at an inner wall of the building hole part 8. COPYRIGHT: (C)2009,JPO&INPIT
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