JP2007107550A - Sealing device for reciprocating shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve pressure resistance of a main lip 12 without increasing a number of parts or complicating installation work. <P>SOLUTION: The sealing device for the reciprocating shaft is provided with a metallic ring 11, the main lip 12 integrally connected to a pressure space A side and slidably and tightly brought into contact with an outer peripheral surface of a shaft 2, a backup ring 15 fitted into a fitting recess 11a formed on an inner peripheral part of the metallic ring 11 on the pressure space A side and supporting the main lip 12 from an atmosphere B side and the inner peripheral side, and a dust lip 16 integrally connected to the metallic ring 11 on an atmosphere B side and slidably and tightly brought into contact with the outer peripheral surface of the shaft 2. The main lip 12 and the dust lip 16 are continued with each other through a through hole 11b provided on the metallic ring 11. The main lip 12 and the dust lip 16 are formed at a time through the through hole 11b of the metallic ring 11 in such a state that the backup ring 15 is fitted to the fitting recess 11a of the metallic ring 11, and the main lip 12 and the dust lip 16 can be integrally formed with the metallic ring 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reciprocating shaft sealing device that seals the circumference of a reciprocating shaft such as a piston rod of a hydraulic shock absorber of a vehicle, for example.

  FIG. 2 is a half cross-sectional view showing a conventional reciprocating shaft sealing device 100 cut along a plane passing through its axis O together with a part of the hydraulic shock absorber. That is, the sealing device 100 is slid onto the outer peripheral surface of the rod 112, which is a reciprocating shaft, on the metal ring 101 made of metal between the caulking end portion 110a of the cylinder 110 of the hydraulic shock absorber and the rod guide 111. The main lip 102 and dust lip 103 in contact with each other and the outer peripheral lip 104 in close contact with the inner peripheral surface of the cylinder 110 are integrally formed of a rubber-like elastic material.

  In the sealing device 100 having the above-described configuration, the main hydraulic lip 102 facing inward (the upper side in FIG. 2) comes into close contact with the outer peripheral surface of the rod 112 with an appropriate tightening allowance, so that the internal hydraulic fluid flows out to the outside. The dust lip 103 facing outward (the lower side in FIG. 2) is brought into close contact with the outer peripheral surface of the rod 112 with an appropriate tightening allowance so that foreign matter enters the cylinder 110 from the outside. Is to prevent.

In this type of sealing device 100, the pressure of the hydraulic oil pressurized by the operation of the internal piston accompanying the impact input acts so as to increase the surface pressure of the main lip 102 against the outer peripheral surface of the rod 112. The main lip 102 needs to have sufficient pressure resistance. As such a method, it is known that the back side and the inner peripheral side of the main lip 102 are supported by a backup ring made of a synthetic resin such as PTFE (see, for example, Patent Document 1 below).
JP 2005-90569 A

  However, according to the technique disclosed in Patent Document 1, an oil seal in which a main lip and an outer peripheral lip are integrally formed on an inner metal ring, and a dust seal in which a dust lip is integrally formed on a metal ring arranged outside the metal ring. Since the back-up ring is fitted between the inner peripheral portions, the number of parts is large, and the assembly work into the hydraulic shock absorber or the like is complicated. Further, in the production thereof, it is necessary to separately perform the molding process of the oil seal and the dust seal, and since the backup ring is incorporated after the molding, the cost is also high in this respect.

  The present invention has been made in view of the above points, and the technical problem is that the pressure resistance of the main lip without increasing the number of parts and the complexity of assembling work. Is to improve.

  As a means for effectively solving the technical problem described above, a sealing device for a reciprocating shaft according to the present invention includes a sealing interposed between an axially reciprocating shaft and an outer peripheral member surrounding the outer periphery thereof. A metal ring, a main lip integrally joined to the pressure space side of the metal ring and slidably in contact with the outer peripheral surface of the shaft, and the pressure space side in the inner peripheral portion of the metal ring A back-up ring that is fitted in a fitting recess formed on the base and supports the main lip from the atmosphere side and the inner circumference side, and is integrally joined to the atmosphere side of the metal ring and can slide on the outer circumference surface of the shaft. The main lip and the dust lip are continuous with each other through a through hole formed in the metal ring.

  The sealing device for a reciprocating shaft having the above-described configuration is configured such that the main lip and the dust lip are passed through the metal ring while the backup ring is fitted in the fitting recess formed on the pressure space side in the inner circumferential portion of the metal ring. Since it can be molded at once through the hole and can be molded integrally with the metal ring, the number of parts does not increase. Further, since the backup ring can be fitted with the main lip during this molding process, the operation of incorporating the backup ring between the main lip and the metal ring can be eliminated. And since the main lip which faced the pressure space side is supported from the inner peripheral side and the atmosphere side by the backup ring, the pressure resistance is improved.

  According to the sealing device for a reciprocating shaft according to the present invention, the pressure resistance of the main lip can be improved by the backup ring without increasing the number of parts and the troublesome work of assembling the device.

  Hereinafter, a reciprocating shaft sealing device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a half sectional view showing a preferred embodiment of a reciprocating shaft sealing device according to the present invention by cutting along a plane passing through its axis O together with a part of a hydraulic shock absorber.

  In FIG. 1, a hydraulic shock absorber to which a sealing device 1 according to the present invention is attached is indicated by a two-dot chain line, and reference numeral 2 is a rod of the hydraulic shock absorber, and the shaft according to claim 1. Reference numeral 3 is a cylinder disposed so as to surround the outer periphery of the rod 2, and corresponds to the outer peripheral member described in claim 1, and reference numeral 4 is fixed to the inner periphery of the cylinder 2. The rod 2 is inserted into the inner peripheral hole 4a so as to be capable of reciprocating in the axial direction. Reference sign A is a pressure space inside the hydraulic shock absorber, and reference sign B is the atmosphere outside the hydraulic shock absorber.

  The sealing device 1 is provided at an outer end portion of the cylinder 3, and includes a metal ring 11, a main lip 12 provided on the pressure space A side of the metal ring 11, and an elastic layer continuously extending to the outer peripheral side thereof. 13, the auxiliary lip 14 formed in the intermediate portion in the radial direction, the backup ring 15 disposed between the inner periphery of the main lip 12 and the inner periphery of the metal ring 11, and the atmosphere B side of the metal ring 11. A provided dust lip 16 and an outer peripheral lip 17 formed on the outer peripheral portion of the elastic layer 13 are provided on the outer peripheral portion of the metal ring 11. The main lip 12, the elastic layer 13, the sub lip 14, the dust lip 16 and the outer peripheral lip 17 are made of a continuous rubber-like elastic material and are integrally vulcanized and bonded to the metal ring 11. No. 15 is formed of a low friction synthetic resin material such as PTFE (polytetrafluoroethylene) having excellent wear resistance and a low friction coefficient.

  The metal ring 11 is manufactured by punching a thick metal plate into a flat washer shape. The metal ring 11 has an inward flange 31 formed at the end of the cylinder 3 so as to be bent toward the inner peripheral side, and an outer end surface 4b of the rod guide 4. Is sandwiched between.

  A fitting recess 11a that is continuous in the circumferential direction is formed on the pressure space A side in the inner periphery of the metal ring 11, and the backup ring 15 is held in the fitting recess 11a. Further, a plurality of through holes 11b are formed at predetermined intervals in the circumferential direction at the outer peripheral side of the fitting recess 11a in the inner peripheral portion. The strip 16 is filled with a continuous rubber-like elastic material.

  The main lip 12 extends from a base portion 12a vulcanized and bonded to the pressure space A side surface of the inner periphery of the metal ring 11 into a conical cylindrical shape having a gradually decreasing diameter toward the pressure space A side. The sealing edge portion 12b formed on the sliding surface 12b and the sliding surface 12c extending from the sealing edge portion 12b toward the atmosphere B are slidably in close contact with the outer peripheral surface 2a of the rod 2 with an appropriate fastening margin.

  The sub lip 14 is formed on an elastic layer 13 extending from the base 12 a of the main lip 12 so as to cover the surface of the metal ring 11 on the pressure space A side, and is in close contact with the outer end surface 4 b of the rod guide 4 together with the elastic layer 13. It is what is done.

  The backup ring 15 has a cross-sectional shape in which the inner peripheral portion protrudes to the pressure space A side (main lip 12 side), and is in a close fitting state in the fitting recess 11 a of the inner peripheral portion of the metal ring 11. While being held, the main lip 12 is in close contact with a surface extending in a substantially conical shape from the atmosphere B side of the sliding surface 12c toward the back surface of the base portion 12a. Since the backup ring 15 is made of the above-described synthetic resin material such as PTFE, the backup lip 15 supports the main lip 12 from the atmosphere B side and the inner peripheral side with a required rigidity.

  The dust lip 16 extends from the base portion 16a vulcanized and bonded to the surface on the atmosphere B side in the inner peripheral portion of the metal ring 11 toward the atmosphere B side, and the inner peripheral portion 16b at the tip thereof extends to the outer peripheral surface 2a of the rod 2. On the other hand, it is brought into close contact with an appropriate tightening allowance. Further, a circumferentially continuous groove 16c is formed on the outer peripheral surface in the vicinity of the tip of the dust lip 16, and this groove 16c is an extract for compensating the tight force of the dust lip 16 against the rod 2. A tension spring 18 is attached.

  The outer peripheral lip 17 extends from the base portion 17a vulcanized and bonded to the pressure space A side surface of the outer peripheral portion of the metal ring 11 toward the pressure space A side, and extends from the outer periphery of the outer end surface 4b of the rod guide 4. It is interposed between 4c and the inner peripheral surface 3a of the cylinder 3 in an appropriately compressed state.

  In the sealing device 1 having the above-described configuration, the main lip 12, the elastic layer 13, the sub lip 14, the dust lip 16 and the outer peripheral lip 17 are formed by applying the metal ring 11 previously applied with a vulcanized adhesive to the fitting recess 11a. An annular ring is defined between the metal ring 11 and the backup ring 15 and the inner surface of the mold by clamping in a predetermined rubber vulcanization molding mold with the backup ring 15 fitted and held. An unvulcanized rubber material is filled into the cavity of the metal, and is heated and pressed to be vulcanized and bonded to the metal ring 11 simultaneously with molding.

  Here, the main lip 12 and the dust lip 16 are formed on the opposite sides of the inner periphery of the metal ring 11 and the backup ring 15. Since it goes around the mold cavities on both sides of the metal ring 11 through the plurality of through holes 11b provided in the metal ring 11, the main lip 12 and the dust lip 16 can be formed in a single forming process. Further, since the backup ring 15 is fitted and held in advance in the fitting recess 11 a of the metal ring 11, the main inner lip 12 is closely fitted with the backup ring 15 at the taper inner peripheral surface on the base 12 a side. Molded into a finished state.

  When the sealing device 1 is attached to the hydraulic shock absorber indicated by a two-dot chain line in FIG. 1, the main lip 12 is slidably brought into close contact with the outer peripheral surface 2 a of the rod 2. The hydraulic oil is prevented from leaking to the atmosphere B side through the outer periphery of the rod 2. The auxiliary lip 14 seals the hydraulic oil between the rod guide 4 and the metal ring 11, and the outer peripheral lip 17 seals the hydraulic oil between the cylinder 3 and the metal ring 11. The dust lip 16 is slidably brought into close contact with the outer peripheral surface 2 a of the rod 2, thereby preventing dust and muddy water on the atmosphere B side from entering the pressure space A through the outer periphery of the rod 2.

  Here, since the main lip 12 faces the pressure space A side, when the hydraulic pressure in the pressure space A rises as a piston (not shown) moves in the axial direction together with the rod 2 in the hydraulic shock absorber, the hydraulic pressure is increased. The main lip 12 acts so as to increase the tightening force to the outer peripheral surface 2a of the rod 2, but the main lip 12 is backed up from the inner peripheral side and the atmosphere A side by a backup ring 15 made of a synthetic resin material. Therefore, an increase in the tightening force of the main lip 12 can be effectively suppressed. Therefore, the settling of the main lip 12 and the early wear of the sliding surface 12c are prevented, and the pressure resistance can be sufficiently improved.

  Further, when the backup ring 15 is mounted between the metal ring 11 and the main lip 12 after forming the main lip 12 or the like, the circumferential direction of the backup ring 15 is cut (bias cut) in order to reduce the diameter of the backup ring 15 once. However, in the embodiment shown in the figure, since the main lip 12 and the like are held in the fitting recess 11a of the metal ring 11, there is no need for such cutting, and therefore a sufficient backup force is required. Have

  In the sealing device 1, the main lip 12, the elastic layer 13, the sub lip 14, the dust lip 16 and the outer peripheral lip 17 are integrally vulcanized and bonded to the metal ring 11, and the backup ring 15 is connected to the main lip 12 and the metal ring 11. Therefore, the number of parts is small and can be easily assembled in the assembly of the hydraulic shock absorber.

  Further, as described above, the main lip 12, the elastic layer 13, the sub lip 14, the outer peripheral lip 17, and the dust lip 16 on the opposite side are simultaneously formed through the through hole 11b of the metal ring 11, It can be molded in a single molding process, and therefore can be manufactured at low cost. Moreover, since the backup ring 15 is held in the fitting recess 11a of the metal ring 11 prior to the formation of the main lip 12 or the like, there is no complication as in the case of fitting after the formation of the main lip 12 or the like.

1 is a half sectional view showing a preferred embodiment of a reciprocating shaft sealing device 1 according to the present invention by cutting along a plane passing through an axis O together with a part of a hydraulic shock absorber. FIG. 5 is a half cross-sectional view showing a conventional reciprocating shaft sealing device 100 cut along a plane passing through its axis O together with a part of a hydraulic shock absorber.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing device 11 Metal ring 11a Fitting recessed part 11b Through hole 12 Main lip 13 Elastic layer 14 Sub lip 15 Backup ring 16 Dustrip 17 Outer lip 18 Extension spring 2 Rod (shaft)
3 Cylinder (outer peripheral member)
4 Rod guide A Pressure space B Air

Claims (1)

  A sealing device (1) interposed between an axially reciprocating shaft (2) and an outer peripheral member (3) surrounding the outer periphery thereof, comprising a metal ring (11) and the metal ring (11) A main lip (12) integrally joined to the pressure space (A) side of the shaft (2) and slidably in contact with the outer peripheral surface (2a) of the shaft (2); and an inner peripheral portion of the metal ring (11) A backup ring (15) which is fitted in a fitting recess (11a) formed on the pressure space (A) side and supports the main lip (12) from the atmosphere (B) side and the inner peripheral side; and the metal ring A dust lip (16) integrally joined to the atmosphere (B) side of (11) and slidably in contact with the outer peripheral surface (2a) of the shaft (2), and the main lip (12) Dustrips (16) are connected to each other through through holes (11b) formed in the metal ring (11). For a reciprocating shaft sealing device according to claim Rukoto.

Images