| 摘要 |
PURPOSE:To prevent an increase of frictional loss of a ring, by providing a part, in which several notches are alternately internally and externally provided to be closely placed, partly to a main unit of the endless ring and absorbing extension and contraction of the ring due to thermal expansion or the like. CONSTITUTION:U-shaped narrow notches 2-5 are provided to a part of the main unit of an endless piston ring 1 with a rectangular section. These notches are alternately internally and externally provided and closely placed. A notched part 6 equipped with such notch is provided to the endless piston ring 1. When an external diameter of the ring 1 fitted into a cylinder is changed for an internal diameter of the cylinder due to a tempeature rise, this change is absorbed by deforming the notched part 6 equipping the many notches 2-4 to a spring shape. |
