| 摘要 |
PURPOSE:To obtain a inexpensive and stable wheel slide mechanism, wherein a plastic wheel and a metal wheel pinion are provided and the coefficient of linear expansion of the plastic material for constituting the wheel exists in a specifc range while the wheel and the wheel pinion are integrally constituted in a rotatable manner by push-in or insert molding. CONSTITUTION:The material quality of a center wheel made of plastics comprises crystaline polyamide resin (nylon) containing 20% of a carbon fiber and the coefficient of linear expansion thereof is 1.5X10<-5>cm/cm/ deg.C. In addition, the material quality of a wheel pinion 6 comprises brass having good free cutting property and barrel treatment is applied thereto but hardening treatment is not applied thereto. As the material of the wheel, a plastic material of which the coefficient of linear expansion exists in a range from 1.0X10<-5> to 3.0X10<-5>cm/ cm/ deg.C is used. |
