| 摘要 |
PROBLEM TO BE SOLVED: To provide a packing for an air cylinder which can be used for a long time without maintenance and which has a stable dynamic friction resistance. SOLUTION: A truncated-conical piston packing for an air cylinder is made of a self-rubricating material 1a on the outside thereof, and an elastic material 1b on the inside thereof, and the top surface, the side surface and a part between the bottom surface and the side surface, which are made of the self- lubricating material are rounded. The friction force between the packing 1 and the cylinder can be stabilized with a low value in an unlubricated condition, thereby it is possible to provide a pneumatic operation type current switchgear which has a stable operating time and requires no maintenance. |
