CAPSTAN DEVICE OF TAPE RECORDER

摘要

PURPOSE:To obtain a capstan having a large coefficient of friction by forming an oxide film at an area to be used as the capstan of a shaft by an electro- chemical process. CONSTITUTION:The 13Cr stainless steel is formed into a rod-shaped shaft body 1. This shaft body 1 is connected to the anode side of an electrode having a cathode and an anode which is obtained by adding 8g/l sodium dichromate into an aqueous solution of 25% sulfuric acid and heating them up to >=70 deg.C. The area of the shaft 1 which is used as a capstan 2 is dipped into the solution and applied with 1-1.3V voltage. Then a black oxide film is formed on the surface of the area of the capstan 2. The lower part of the shaft thus obtained is fixed the center of a flywheel 3 and then pierced through a bearing 4. Thus a rotary shaft 2' is obtained, and the capstan 2 is projected over a chassis 5. The capstan 2 can have a large coefficient of friction owing to the black oxide film.