| 摘要 |
PROBLEM TO BE SOLVED: To facilitate assembly by setting the lateral dimension of a synthetic resin-made projection provide don a drive gear in such a manner that the projection is tightened and fitted in a groove of a drive shaft due to thermal expansion at the time of operation. SOLUTION: In a governor drive gear 4 made of a synthetic resin material, a keylike projection 4a is formed at the time of molding in a hole 4b in which it is fitted in a crank shaft 3. Moreover, a groove 3a is formed in the crank shaft 3 made of a steel material by machining. Here, the width E of the groove 3a is +0.024 mm to +0.050 mm for the reference dimension, and the width e of the projection 4a is 0 to 0.010 mm for the reference dimension. Consequently, it is fitted loosely at the time of assembly at a normal temperature, and the projection 4a made of a synthetic resin material which has a large coefficient of thermal expansion is expanded at the time of opeartion when the ambient temperature rises and is fitted tightly. Consequently, the assembly becomes very easy, and assembly man-hour is reduced. On the other hand, the generation of noise is prevented due to tight fitting at the time of operation, and the occurrence of galling in a meshing part and the occurrence of wear of fitting faces can be avoided. |
