| 摘要 |
PURPOSE:To aim at lessening friction torque to the same axial thrust, by forming a convexity around a shaft hole at the end of an aval cam to make this convexity an axial thrust receiver, which contacts bearings, and contracting both a sliding area and a sliding radius. CONSTITUTION:A minute stage gap part 13a (state gap size: 0.001mm. or so) equal to the hole of a rotary shaft 14 as in concentrically circular form is formed convexly on a surface vertical to the rotary shaft 14 of an oval cam 13 and the related structure is made up so as to cause axial thrust to be received with a convex part 13a and a bearing 5. With this, as shown in C-C sectional drawing, not only the sliding radius and area values of the stage gap part 13a can be considerably decreased but friction torque can be lessened. In addition, a shallow groove 14a is formed at the thermal position of the stage gap part 13a on the circumference of the rotary shaft 14 whereby when shrinkage fitting between the shaft 14 and the cam 13 takes place, residual stress 15 of the oval cam 13 after being cooled is released in the shaft center direction, preventing protuberant deformation on the side of the bearing 5. |
