| 摘要 |
PURPOSE:To prevent generation of spark between commutator piece and brush and restrain electric noise by injecting electroconductive mixture of electroconductive particle and oily substance, in a clearance formed between commutator pieces. CONSTITUTION:Commutator pieces 3-1-3-3 are arranged at equal interval on the outer circumference of insulative cylinder 2, and electroconductive mixture 5 is injected into a clearance between commutator pieces 3-1-3-3. This electroconductive mixture 5 is prepared as a solid creamy material like butter by kneading electroconductive particles such as pulverized metal or carbon, and oily substance. It is retained by injecting it into electroconductive mixture sumps 6-1, 6-2 provided in insulative cylinder 2. In this way, it is possible to prevent spark generation and resultantly restrain electric noise generation, because the electroconductive mixture 5 has the same voltage-current property as a varister. In addition, cost can be minimized due to installation of spark-preventive parts being dispensed with. |
