JP2007292191A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain sound sealing performance for a long period while suppressing the deterioration of seal lips 11, 12 due to heat load. <P>SOLUTION: This sealing device 1 comprises a metal ring 14 fixed to a housing in a tightly fitted condition, and the seal lips 11, 12 integrally provided on the metal ring 14 and each formed of a rubber elastic material whose whole periphery is slidably put in close contact with the outer peripheral face of a shaft 3 inserted through the housing 2. A plurality of irregularities 14a, 14b are formed on the outside face of the metal ring 14 exposed to the outside of the housing 2 for increasing the heat radiation area of the metal ring 14 while preventing or suppressing the accumulation of heat. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sealing device for sealing a shaft periphery.

As a typical prior art of a sealing device used as a shaft circumferential sealing means such as a piston rod of a hydraulic shock absorber (shock absorber) of a vehicle, for example, there is one described in Patent Document 1 below.
Japanese Patent Laid-Open No. 2001-173797

  FIG. 3 is a cross-sectional view showing the conventional sealing device described in Patent Document 1 cut along a plane passing through its axis together with a part of the hydraulic shock absorber. In FIG. 3, the sealing device 100 is interposed between the housing 2 of the hydraulic shock absorber and the piston rod 3, and is integrally formed with a rubber-like elastic material on the inner periphery of a flat washer-like metal ring 104. The main lip 101 and the dust lip 102, and the outer peripheral gasket 103 integrally formed of a rubber-like elastic material on the outer peripheral portion of the metal ring 104.

  The oil main lip 101 facing the inside of the housing 2 is provided with an extension spring 105 for compensating the tight force on the outer periphery, and the inner periphery has an appropriate tightening allowance on the outer peripheral surface of the piston rod 3. The inner fluid O is prevented from flowing out of the housing 2 by being in close contact with each other, and the dust lip 102 is in close contact with the outer peripheral surface of the piston rod 3 with an appropriate tightening allowance. This prevents foreign matter from entering the housing 2 from the outside.

  By the way, this type of hydraulic shock absorber obtains damping against vibration by viscous resistance when the hydraulic oil O flows through an orifice opened in a piston (not shown), in other words, converts kinetic energy into heat energy. By doing so, the vibration is attenuated. Further, since the main lip 101 and the dust lip 102 slide with the piston rod 3 that reciprocates by the input of vibration, frictional heat is generated at the sliding portion.

  Therefore, when the heat generated by the mechanism as described above is accumulated, the main lip 101 and the dust lip 102 formed of the rubber-like elastic material are cured, that is, the rubber material is deteriorated by the heat load, and the sealing is performed. There was a risk that the performance would be degraded.

  The present invention has been made in view of the above points, and the technical problem is to suppress the deterioration of the seal lip due to a thermal load and maintain the soundness of the sealing performance over a long period of time. is there.

  As means for effectively solving the technical problem described above, the present invention includes a metal ring fixed in a tightly fitted state in a housing, and a shaft that is integrally provided in the metal ring and inserted into the housing. And a sealing lip made of a rubber-like elastic material whose entire circumference is slidably in close contact with the outer peripheral surface of the metal ring. A plurality of irregularities are formed on the outer surface of the metal ring exposed to the outside of the housing. It has been done.

  That is, by forming a plurality of irregularities on the outer surface of the metal ring exposed to the outside of the housing, the surface area of the outer surface, in other words, the heat dissipation area when heat is transferred to the metal ring is increased. Is prevented or suppressed.

  According to the sealing device of the present invention, by forming a plurality of irregularities on the outer surface of the metal ring, the amount of heat released to the outside increases, and thus the thermal load on the seal lip made of a rubber-like elastic material is reduced. Therefore, the soundness of the sealing performance can be maintained over a long period.

  Hereinafter, a preferred embodiment of a sealing device according to the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a sealing device according to the present invention by cutting along a plane passing through its axial center together with a part of a hydraulic shock absorber, and FIG. 2 shows the sealing device of FIG. It is a half sectional view of the unmounted state shown by cutting along a plane passing through the heart.

  In FIG. 1, reference numeral 2 is a hydraulic shock absorber housing, reference numeral 3 is a piston rod that is inserted into the inner periphery of the housing 2 and operates a piston (not shown) in the housing 2, and reference numeral 4 is a housing. 2 is a rod guide that is fixed to the inner periphery of 2 and supports the piston rod 3 so as to be movable in the axial direction. The piston rod 3 corresponds to the shaft described in claim 1.

  The sealing device 1 is attached to the end of the housing 2 and seals the axial circumference of the piston rod 3. As shown in an enlarged view in FIG. It has a main lip 11 and a dust lip 12 that are integrally formed of a material, and an outer peripheral gasket 13 that is integrally formed of a rubber-like elastic material on the outer periphery of the metal ring 14. The main lip 11 and the dust lip 12 correspond to the seal lip described in claim 1.

  That is, the sealing device 1 positions and sets a metal ring 14 pre-applied with a vulcanizing adhesive in a predetermined mold (not shown), and defines a space between the metal ring 14 and the inner surface of the mold when the mold is closed. The formed annular cavity is filled with an unvulcanized rubber material for molding and heated and pressurized, so that the main lip 11, the dust lip 12 and the outer gasket 13 are vulcanized together with the metal ring 14 at the same time. It is manufactured by sulfur bonding.

  The main lip 11 extends from the inner peripheral end of the metal ring 14 toward the inner side of the housing 2 in a conical cylinder shape having a small diameter on the front end side. The main lip 11 has a V-shaped cross-sectional shape on the inner peripheral surface. The seal protrusion 11a formed continuously in the circumferential direction is brought into close contact with the outer peripheral surface of the piston rod 3 with an appropriate tightening allowance, so that the internal hydraulic oil O flows out of the housing 2 from the shaft periphery. It is a seal for oil which prevents A circumferentially continuous groove 11b is formed on the outer peripheral surface of the main lip 11 so as to be positioned on the outer peripheral side of the seal protrusion 11a, and the tension of the main lip 11 against the piston rod 3 is formed in the groove 11b. An extension spring 15 for compensating the force is attached.

  The dust lip 12 extends from the inner peripheral end of the metal ring 14 toward the side opposite to the main lip 11 (external space side) in a conical cylinder shape having a small diameter on the front end side, and the inner peripheral end thereof is a piston rod. In this way, external foreign matter is prevented from entering the housing 2 from the shaft periphery by being brought into close contact with the outer peripheral surface 3 with an appropriate tightening allowance.

  The outer periphery gasket 13 is vulcanized and bonded to the inner surface of the outer peripheral portion of the metal ring 14 and extends toward the inside of the housing 2, and is compressed between the outer peripheral portion of the rod guide 4 and the inner peripheral surface of the housing 2. By interposing, the hydraulic oil O is sealed on the outer peripheral side of the rod guide 4.

  The metal ring 14 is formed in a flat washer shape, and an outer peripheral portion thereof is caulked and fixed to the outside of the rod guide 4 by a caulking portion 2 a formed to bend at an end portion of the housing 2. A large number of concentric grooves 14a are formed on the outer surface of the metal ring 14, and the grooves 14a and the relative protrusions 14b therebetween constitute the irregularities described in claim 1. ing. The groove 14a is formed in a region between a portion in contact with the caulking portion 2a and a portion where the base portion 12a of the dust strip 12 is vulcanized and bonded.

  In the above configuration, as described above, this type of hydraulic shock absorber converts kinetic energy into heat energy by viscous resistance when hydraulic oil O flows through an orifice formed in a piston (not shown). Therefore, heat is generated inside, and this heat is transmitted to the sealing device 1 as well. Further, the main lip 11 and the dust lip 12 in the sealing device 1 also generate heat by sliding with the piston rod 3.

  However, in the sealing device 1 of the present invention, concavities and convexities are formed on the outer surface of the metal ring 14 exposed to the outside of the housing 2 by a large number of concentric grooves 14a and relative protrusions 14b therebetween. Therefore, the heat dissipation area to the atmosphere increases. For this reason, since the temperature rise by the above heat_generation | fever is suppressed, the thermal load of the main lip 11 and dust strip 12 which consist of rubber-like elastic materials is reduced, and the soundness of sealing performance can be maintained over a long term.

  In addition, the unevenness | corrugation of the outer surface of the metal ring 14 is not limited to the thing by the concentric groove | channel 14a (and protrusion part 14b), The thing of various shapes is applicable. Further, the present invention is not limited to the above-described sealing device for a hydraulic shock absorber, and can be applied to a sealing device that seals the periphery of the rotating shaft, for example, as long as the metal ring is exposed to the outside.

It is sectional drawing which cut | disconnects and shows the sealing device which concerns on this invention in the plane which passes along the axial center with a part of hydraulic shock absorber. FIG. 2 is a one-side cross-sectional view of an unmounted state in which the sealing device of FIG. 1 is cut along a plane passing through its axis. It is sectional drawing which cut | disconnects and shows the conventional sealing device by the plane which passes along the axial center with a part of hydraulic shock absorber.

Explanation of symbols

1 Sealing device 11 Main lip (seal lip)
12 Dustrip (seal lip)
13 Outer peripheral gasket 14 Metal ring 14a Groove (unevenness)
14b Ridge (unevenness)
15 Extension spring 2 Housing 2a Caulking part 3 Piston rod (shaft)
4 Rod guide

Claims (1)

  A metal ring (14) fixed to the housing (2) in a close fitting state, and an outer peripheral surface of the shaft (3) provided integrally with the metal ring (14) and inserted through the housing (2). In the sealing device (1) including a seal lip (11, 12) made of a rubber-like elastic material that is slidably in contact with the entire circumference, the metal ring (14) exposed to the outside of the housing (2) A sealing device in which a plurality of irregularities (14a, 14b) are formed on the outer surface of the sealing member.

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