JP2018179141A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an increase of slide resistance and slide heat generation even if an inner seal ring contacts with an opposing face of an external peripheral side member due to the occurrence of settling at an outer seal ring, in a sealing device which is composed of a combination of the inner seal ring, the outer seal ring and a back ring.SOLUTION: A sealing device 1 is composed of a combination of an inner seal ring 11 arranged at an internal peripheral side of an opposing face of an external peripheral side member 43 in a non-contact manner, an outer seal ring 21 which is held to a holding groove 12 formed at an external peripheral face of the inner seal ring 11, and slidably contacts with the opposing face of the external peripheral side member 43, and a back ring 31 arranged at an internal peripheral side of the inner seal ring 11. A large number of recesses 14 aligned in a circumferential direction are formed at a face opposing the opposing face of the external peripheral side member 43 out of the external peripheral face of the inner seal ring 11 in a non-contact manner.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a sealing device according to sealing technology.

  The applicant of the present invention has previously proposed a sealing device 51 shown in FIG. 5, and this sealing device 51 is the inner peripheral side of the inner peripheral side member 41 and the outer peripheral side member 43 which move relative to each other. A sealing device mounted in the mounting groove 42 provided on the opposing surface of the member 41, and is provided with an inner seal ring 61 disposed non-contactingly on the inner peripheral side of the opposing surface of the outer peripheral side member 43; An outer seal ring 71 which is held by a holding groove 62 provided on the outer peripheral surface and slidably contacts an opposing surface of the outer peripheral side member 43, and a back ring 81 disposed on the inner peripheral side of the inner seal ring 61 It is supposed to be a combination of

JP, 2015-178890, A Patent No. 6017738

  The sealing device 51 having the above configuration combines the outer seal ring 71 made of a low friction material such as PTFE or urethane with the outer peripheral surface of the inner seal ring 61 made of a high rigidity material, thereby reducing the friction coefficient to a low level. Although dynamic resistance and sliding heat generation can be reduced, further improvement in performance is expected with respect to reducing this sliding resistance and sliding heat generation.

  In view of the foregoing, the present invention provides a sealing device comprising a combination of an inner seal ring, an outer seal ring, and a buckling, wherein the outer seal ring becomes loose and the inner seal ring contacts the opposing surface of the outer peripheral member. Also, it is an object of the present invention to provide a sealing device capable of suppressing an increase in sliding resistance and sliding heat generation.

  In order to solve the above problems, the sealing device of the present invention is mounted in a mounting groove provided on the opposite surface of the inner peripheral side member of the inner peripheral side member and the outer peripheral side member which move relative to each other. And a sealing device for suppressing leakage of the object to be sealed on the high-pressure side between the opposing surfaces of the two members by closely contacting the opposing surfaces of the outer-peripheral members, An inner seal ring disposed in non-contacting on the inner peripheral side of the opposing surface and a holding groove provided on the outer peripheral surface of the inner seal ring, as well as being slidably in contact with the opposing surface of the outer peripheral member And a back ring disposed on the inner peripheral side of the inner seal ring, and the outer peripheral surface of the inner seal ring is opposed to the opposing surface of the outer peripheral member in a non-contact manner. The surface, characterized in that a plurality of recesses arranged in the circumferential direction.

  In one embodiment, the recess has a shape such that the cross-sectional area cut in the direction perpendicular to the axis gradually reduces as the axial end of the inner seal ring approaches the holding groove. It features.

  Further, as an embodiment, a surface of the outer peripheral surface of the inner seal ring that faces in a non-contacting manner with the opposing surface of the outer peripheral member is provided with the concave portion so that a peak-and-valley curve continues in the circumferential direction It is characterized in that it is shaped.

  In the present invention, a large number of recessed portions aligned in the circumferential direction are provided on the outer peripheral surface of the inner seal ring that faces in a non-contact manner with the opposing surface of the outer peripheral side member. Even if the inner seal ring contacts the opposing surface of the outer peripheral side member, the contact area is limited. Therefore, it is possible to suppress an extreme increase in sliding resistance and sliding heat generation as compared to the state before contact.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the sealing device which concerns on embodiment of this invention, (A) is the principal part top view, (B) is a principal part side view, (C) is principal part sectional drawing Principal part sectional perspective view of the same sealing device It is a figure which shows the sealing device which concerns on other embodiment of this invention, (A) is the principal part top view, (B) is a principal part side view, (C) is principal part sectional drawing Principal part sectional perspective view of the same sealing device Principal part sectional view of the sealing device according to the background art

  FIG. 1 shows a sealing device 1 according to the embodiment. The sealing device 1 according to the embodiment is opposed to the piston 41 of the piston (inner peripheral side member) 41 and the cylinder (cylinder tube, outer peripheral side member) 43 in the reciprocating hydraulic cylinder that moves relative to each other. The ring 41 is mounted on an annular mounting groove 42 provided on the surface (outer peripheral surface) and is slidably in close contact with the opposing surface (inner peripheral surface) of the cylinder 43 so that the piston 41 and the cylinder 43 face each other on the high pressure side. It is a sealing device (piston seal) which suppresses that a sealing object (pressure oil etc.) leaks to the low pressure side. Further, the sealing device 1 includes, as its component parts, the inner seal ring 11 disposed in non-contact on the inner peripheral side of the facing surface of the cylinder 43 and the annular holding groove 12 provided on the outer peripheral surface of the inner seal ring 11. It is made up of a combination of an outer seal ring 21 held and being slidably in contact with the opposing surface of the cylinder 43 and a back ring 31 disposed on the inner peripheral side of the inner seal ring 11.

  Among these, the inner seal ring 11 is a material having a rigidity higher than that of the outer seal ring 21, and specifically, a high strength resin material such as polyamide resin, polyacetal resin, polyethylene resin, polyimide resin, PEEK (tensile strength: 40 MPa Or more). Further, the inner seal ring 11 does not contact the facing surface of the cylinder 43 and does not have an outer diameter tightening margin with respect to the facing surface of the cylinder 43 so as to set a predetermined radial gap between the facing surface and the facing surface of the cylinder 43 The outer diameter is set to be slightly smaller than the inner diameter of the cylinder 43. Further, the inner seal ring 11 is formed in a shape cut at one location on the circumference, and provided with a cut portion (not shown) at one location on the circumference. Further, the inner seal ring 11 is formed into a rectangular shape having a long cross section in the axial direction, and an annular holding groove 12 is provided at the axial center of the outer peripheral surface thereof. An annular inclined surface (taper surface) 13 is provided which is directed to gradually decrease from the central portion to the axial end.

  The outer seal ring 21 is a material having a lower friction than the inner seal ring 11, and specifically, is formed of PTFE (tetrafluoroethylene resin), urethane or rubber. Further, the outer seal ring 21 is fitted in the holding groove 12 provided on the outer peripheral surface of the inner seal ring 11, held by the inner seal ring 11, and formed in a size close to sliding against the opposing surface of the cylinder 43. That is, the outside diameter size thereof is set to be slightly larger than the inside diameter size of the cylinder 43. The outer seal ring 21 is formed in an endless shape having no circumferential cut portion. Further, the outer seal ring 21 is formed into a rectangular shape that is long in the axial direction, and is accommodated in the holding groove 12. Further, since the outer seal ring 21 is accommodated in the holding groove 12 at the inner peripheral portion excluding the outer peripheral portion, the inner seal ring 11 and the outer seal ring 21 overlap and are arranged at a part in the radial direction It is done.

  The back ring 31 is a material of higher elasticity than the inner seal ring 11 and the outer seal ring 21, and is specifically formed of rubber or urethane. Further, the back ring 31 has elasticity to press the outer seal ring 12 against the opposite surface of the cylinder 43 via the inner seal ring 11, that is, the inner diameter is set to be slightly smaller than the outer diameter at the groove bottom of the mounting groove 42. ing. Further, the buckling 31 is formed in an endless shape having no circumferential cut portion. The back ring 31 is formed into a rectangular shape having a long cross section in the radial direction, and the axial width thereof is set to be slightly smaller than the axial width of the inner seal ring 11. Further, the back ring 31 is provided with chamfered portions 32 each having an arc shape in cross section or a linear shape in cross section at four corners of the cross section rectangular shape.

  With the above-described configuration, the sealing device 1 can reduce the friction coefficient at the sliding portion low and can reduce the sliding resistance and sliding heat generation when the piston 41 is operated, but the outer seal ring 21 has a looseness and the inner If the seal ring 11 directly contacts the opposite surface of the cylinder 43, there is a concern that the sliding resistance and the sliding heat generation may increase. Then, the following measures are taken to the said sealing device 1 as a further structure.

  That is, among the outer peripheral surface of the inner seal ring 11, a large number of recessed portions 14 aligned in the circumferential direction are provided on the surface facing in a non-contact manner with the opposing surface of the cylinder 43. The contact area to contact the opposite surface of the cylinder 43 is reduced when it contacts with. The surface facing the opposing surface of the cylinder 43 in a non-contacting manner is a region obtained by subtracting the holding groove 12 from the outer peripheral surface of the inner seal ring 11, and in this region, as described above, the outer diameter dimension is from the axial center Since the annular inclined surface 13 directed to gradually decrease toward the axial end is provided, the inclined surface 13 is provided with a large number of recesses 14 aligned in the circumferential direction.

  As the shape of each recess 14, the recess 14 is opened at the axial end 11 a of the inner seal ring 11 as a rectangular or sector opening having a predetermined depth d and width w. Further, as the recess 14 is gradually reduced in depth and / or width as it approaches the holding groove 12 from the axial end 11 a of the inner seal ring 11, the cross-sectional area cut in the direction perpendicular to the axial direction Is formed in a shape which gradually shrinks, which makes it possible to generate a dynamic pressure by the wedge effect when the piston 41 is operated.

  According to the sealing device 1 configured as described above, the contact area is limited even if the outer seal ring 21 is loosened and the inner seal ring 11 directly contacts the opposing surface of the cylinder 43. Ru. Therefore, it is possible to suppress the sliding resistance and the sliding heat generation from being extremely increased as compared with the state before the contact.

  Further, as described above, since the cross-sectional area of the recess 14 gradually shrinks as it approaches the holding groove 12 from the axial end 11a of the inner seal ring 11, this shape allows the piston 41 to move when the piston 41 is actuated. Dynamic pressure is generated by the effect. Therefore, since the sliding resistance and the sliding heat generation can be reduced by this dynamic pressure, it is possible to suppress the sliding resistance and the sliding heat generation from being extremely increased.

  As another shape of the recess 14, for example, as shown in FIG. 3 and FIG. 4, of the outer peripheral surface of the inner seal ring 11, the surface facing the surface opposed to the cylinder 43 in non-contact, By providing 14, it can be considered that the peak-and-valley curve has a continuous wave shape in the circumferential direction. In this case, the inner seal ring 11 is in line contact with the opposite surface of the cylinder 43 only with the ridges of the peak in the wave shape. Do. Therefore, since the contact area is extremely limited, it is possible to more effectively suppress the increase in the sliding resistance and the sliding heat generation as compared with the state before the contact.

  Further, in this case, since the stress generated at the contact portion of the inner seal ring 11 is dispersed, the local load is reduced. Therefore, damage to the inner seal ring 11 can be suppressed, and the durability of the inner seal ring 11 can be improved.

  In the present invention, the shape of the recess 14 is not particularly limited. However, in order to prevent the outer seal ring 21 from protruding and breaking, the recess 14 preferably has a shape that does not reach the holding groove 12.

DESCRIPTION OF SYMBOLS 1 Sealing device 11 inner seal ring 11a axial end 12 holding groove 13 inclined surface 14 recessed part 21 outer seal ring 31 back ring 32 chamfered part 41 piston (inner peripheral side member)
42 Mounting groove 43 Cylinder (outer side member)

The back ring 31 is a material of higher elasticity than the inner seal ring 11 and the outer seal ring 21, and is specifically formed of rubber or urethane. Further, the back ring 31 has elasticity to press the outer seal ring 21 against the opposite surface of the cylinder 43 through the inner seal ring 11, that is, the inner diameter is set slightly smaller than the outer diameter at the groove bottom of the mounting groove 42. ing. Further, the buckling 31 is formed in an endless shape having no circumferential cut portion. The back ring 31 is set slightly smaller than the axial width of the inner seal ring 11 the axial width of that. Further, the back ring 31 is provided with chamfered portions 32 each having an arc shape in cross section or a linear shape in cross section at four corners of the rectangular shape in cross section.

Claims (3)

It is mounted in a mounting groove provided on the opposite surface of the inner peripheral side member of the inner peripheral side member and the outer peripheral side member which move relative to each other, and is in close contact with the opposed surface of the outer peripheral side member A sealing device for suppressing leakage of a target to be sealed on the high pressure side to the low pressure side between opposing surfaces of the two members by
It is held by an inner seal ring disposed non-contactingly on the inner peripheral side of the opposing surface of the outer peripheral side member, and a holding groove provided on the outer peripheral surface of the inner seal ring and slides against the opposing surface of the outer peripheral side member It comprises a combination of an outer seal ring that comes in movable contact and a buckling that is disposed on the inner circumferential side of the inner seal ring,
A sealing device characterized in that a large number of recessed portions aligned in a circumferential direction are provided on a surface of the outer peripheral surface of the inner seal ring that faces in a non-contact manner with the facing surface of the outer peripheral member. In the sealing device according to claim 1,
The sealing device is characterized in that the recessed portion is shaped such that the cross-sectional area cut in the direction perpendicular to the axis gradually reduces as it approaches the holding groove from the axial end of the inner seal ring. In the sealing device according to claim 1 or 2,
Of the outer peripheral surface of the inner seal ring, the surface facing in non-contact with the opposing surface of the outer peripheral member is provided with the recess so that the peak-and-valley curve has a corrugated shape continuing in the circumferential direction. Sealing device to feature.

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