| 摘要 |
PURPOSE:To improve sealing property by arranging a cylindrical ring in a position corresponding to a stepped slide surface of a rotary shaft to use differential pressure of air for energizing force of the cylindrical ring when the stepped slide surface is pressed and energized by spring force. CONSTITUTION:When a rotary shaft 10 provided with a large diameter portion 12 and a small diameter portion 14 is supported in a housing 20, a cylindrical ring 17 is disposed in a position of the housing 20 corresponding to a stepped slide surface 16 of the rotary shaft 10, and a ring 17 is pressed leftward and energized by a coil spring 19 fitted on a pin 18. Also, then, assuming pressures in respective chambers at both sides of the housing 20 are P1, P2 (P1>P2), the pressure P1 acts on the back of the cylindrical ring 17 while the pressure P2 acts on a gap between the rotary shaft 10 and the housing 20. and pressure (P1+P2)/2 acts on the slide surface 16 and the pressure P1 acts on the rear of the cylindrical ring 17 so that the cylindrical ring 17 is leftward urged by the differential pressure to improve sealing property. |
