Sealing device

Abstract

Provided is a sealing device that is capable of exhibiting a sealing function even in a condition in which a fluid pressure is low while suppressing its sliding torque. A sealing device 100 is characterized by including: a seal ring 200 made of resin which is in close contact with a side wall surface on a low pressure side of an annular groove 410 , and slides against an inner peripheral surface of a shaft hole in a housing 500 through which a shaft 400 is inserted; and a metal spring 300 which is provided along an inner peripheral surface of the seal ring 200 in a state in which a gap is formed between the metal spring 300 and a groove bottom surface of the annular groove 410 , and presses the seal ring 200 toward an outer peripheral surface side, wherein a concave portion 220 is formed on an outer peripheral surface of the seal ring 200 which extends from an end portion on a high pressure side of the outer peripheral surface to a position which does not reach an end portion on a low pressure side of the outer peripheral surface, and introduces a fluid from the high pressure side.

1 . A sealing device which is attached to an annular groove provided on an outer periphery of a shaft and holds a fluid pressure in a sealing target area by sealing an annular gap between the shaft and a housing rotating relative to each other, the sealing target area being configured such that the fluid pressure changes,
 the sealing device comprising:   a seal ring made of resin which is in close contact with a side wall surface on a low pressure side of the annular groove, and slides against an inner peripheral surface of a shaft hole in the housing through which the shaft is inserted; and   a metal spring which is provided along an inner peripheral surface of the seal ring in a state in which a gap is formed between the metal spring and a groove bottom surface of the annular groove, and presses the seal ring toward an outer peripheral surface side, wherein   a concave portion is formed on an outer peripheral surface of the seal ring which extends from an end portion on a high pressure side of the outer peripheral surface to a position which does not reach an end portion on a low pressure side of the outer peripheral surface, and introduces a fluid from the high pressure side.   
     
     
         2 . The sealing device according to  claim 1 , wherein a plurality of the concave portions are formed at intervals in a circumferential direction. 
     
     
         3 . The sealing device according to  claim 1 , wherein a guide portion which positions the metal spring in an axial direction is formed on the inner peripheral surface of the seal ring. 
     
     
         4 . A sealing device which is attached to an annular groove provided on an outer periphery of a shaft and holds a fluid pressure in a sealing target area by sealing an annular gap between the shaft and a housing rotating relative to each other, the sealing target area being configured such that the fluid pressure changes,
 the sealing device comprising:   a seal ring made of resin which is in close contact with a side wall surface on a low pressure side of the annular groove, and slides against an inner peripheral surface of a shaft hole in the housing through which the shaft is inserted; and   a metal spring which is provided along an inner peripheral surface of the seal ring in a state in which a gap is formed between the metal spring and a groove bottom surface of the annular groove, and presses the seal ring toward an outer peripheral surface side, wherein   a concave portion is formed on an outer peripheral surface of the seal ring which extends from an end portion on a high pressure side of the outer peripheral surface to a position which does not reach an end portion on a low pressure side of the outer peripheral surface, and introduces a fluid from the high pressure side, and   a guide portion which positions the metal spring in an axial direction is formed on the inner peripheral surface of the seal ring, and a protrusion which prevents the metal spring from being detached to an inner peripheral surface side is provided at a tip of the guide portion.   
     
     
         5 . A sealing device which is attached to an annular groove provided on an outer periphery of a shaft and holds a fluid pressure in a sealing target area by sealing an annular gap between the shaft and a housing rotating relative to each other, the sealing target area being configured such that the fluid pressure changes,
 the sealing device comprising:   a seal ring made of resin which is in close contact with a side wall surface on a low pressure side of the annular groove, and slides against an inner peripheral surface of a shaft hole in the housing through which the shaft is inserted; and   a metal spring which is provided along an inner peripheral surface of the seal ring in a state in which a gap is formed between the metal spring and a groove bottom surface of the annular groove, and presses the seal ring toward an outer peripheral surface side, wherein   a concave portion is formed on an outer peripheral surface of the seal ring which extends from an end portion on a high pressure side of the outer peripheral surface to a position which does not reach an end portion on a low pressure side of the outer peripheral surface, and introduces a fluid from the high pressure side, and   an abutment portion is provided at one position on the seal ring in a circumferential direction, and protrusions which restrict a movement of the metal spring in the circumferential direction are provided on the inner peripheral surface on both sides of the abutment portion.   
     
     
         6 . A sealing device which is attached to an annular groove provided on an outer periphery of a shaft and holds a fluid pressure in a sealing target area by sealing an annular gap between the shaft and a housing rotating relative to each other, the sealing target area being configured such that the fluid pressure changes,
 the sealing device comprising:   a seal ring made of resin which is in close contact with a side wall surface on a low pressure side of the annular groove, and slides against an inner peripheral surface of a shaft hole in the housing through which the shaft is inserted; and   a metal spring which is provided along an inner peripheral surface of the seal ring in a state in which a gap is formed between the metal spring and a groove bottom surface of the annular groove, and presses the seal ring toward an outer peripheral surface side, wherein   a concave portion is formed on an outer peripheral surface of the seal ring which extends from an end portion on a high pressure side of the outer peripheral surface to a position which does not reach an end portion on a low pressure side of the outer peripheral surface, and introduces a fluid from the high pressure side,   a guide portion which positions the metal spring in an axial direction is formed on the inner peripheral surface of the seal ring, and a first protrusion which prevents the metal spring from being detached to an inner peripheral surface side is provided at a tip of the guide portion, and   an abutment portion is provided at one position on the seal ring in a circumferential direction, and second protrusions which restrict a movement of the metal spring in the circumferential direction are provided on the inner peripheral surface on both sides of the abutment portion.   
     
     
         7 . The sealing device according to  claim 4 , wherein a convex portion which extends in the circumferential direction is provided at a center in a width direction on the outer peripheral surface of the seal ring, and a portion closer to the high pressure side than the convex portion is the concave portion. 
     
     
         8 . The sealing device according to  claim 2 , wherein a guide portion which positions the metal spring in an axial direction is formed on the inner peripheral surface of the seal ring. 
     
     
         9 . The sealing device according to  claim 5 , wherein a convex portion which extends in the circumferential direction is provided at a center in a width direction on the outer peripheral surface of the seal ring, and a portion closer to the high pressure side than the convex portion is the concave portion. 
     
     
         10 . The sealing device according to  claim 6 , wherein a convex portion which extends in the circumferential direction is provided at a center in a width direction on the outer peripheral surface of the seal ring, and a portion closer to the high pressure side than the convex portion is the concave portion.