JP2015045357A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device capable of maintaining bearing force of a backup ring 3 with respect to a main lip 12 even in a case where high pressure acts.SOLUTION: In a sealing device, a main lip 12 which comprises a rubber-like elastic material and is closely contacted with the outer peripheral surface of a shaft 113 in a state of facing toward a sealing space A side of an inner diameter part 21b of an annular substrate 21 is provided on the sealing space A side; a backup ring 3 bearing the main lip 12 from an atmosphere B side and an inner peripheral side is arranged between the inner diameter part 21b of the annular substrate 21 and the main lip 12; and the backup ring 3 and the inner diameter part 21b of the annular substrate 21 are engaged with each other in a radial direction through engagement means 3a, 21c.

Description

  The present invention relates to a sealing device used as a sealing means for a reciprocating shaft in, for example, a hydraulic shock absorber of a vehicle.

  As a sealing device used in a hydraulic shock absorber (shock absorber) of a vehicle, for example, a device described in Patent Document 1 below is known.

  FIG. 4 shows a conventional sealing device of this type in an unmounted state, and FIG. 5 shows a mounted state in a hydraulic shock absorber. That is, this sealing device includes an oil seal 101 that seals hydraulic oil inside the hydraulic shock absorber 110, a dust seal 102 that prevents foreign matter and muddy water from entering, and a backup ring 103. Metal annular substrates 101 a and 102 a in 101 and 102 are sandwiched between a caulking portion 111 a at the open end of the cylinder 111 in the hydraulic shock absorber 110 and a rod guide 112 inside thereof.

  The oil seal 101 includes a main lip 101b that is in close contact with the outer peripheral surface of the piston rod 113 in a state in which the annular sealant 101a faces the sealed space (the internal space side of the hydraulic shock absorber 110), a cylinder 111, and a rod guide 112. The outer peripheral lip 101c that seals between the two is integrally molded (vulcanized and bonded) with a rubber-like elastic material, and the dust seal 102 is an annular substrate 102a that is fitted and integrated with the annular substrate 101a at outer diameter portions. Further, the dust lip 102b that is in close contact with the outer peripheral surface of the piston rod 113 in a state of facing the atmosphere side is integrally molded (vulcanized and bonded) with a rubber-like elastic material. The backup ring 103 is made of a synthetic resin, and is held between the vicinity of the root of the main lip 101b of the oil seal 101 and the inner peripheral portion of the annular substrate 102a in the dust seal 102. And it supports from the inner peripheral side and suppresses deformation of the main lip 101b due to the hydraulic pressure inside the hydraulic shock absorber 110.

  That is, in this sealing device, as shown in FIG. 5, the main lip 101 b of the oil seal 101 is brought into close contact with the outer peripheral surface of the piston rod 113 with an appropriate tightening allowance, so that the internal hydraulic oil is supplied to the hydraulic shock absorber 110. The dust seal 102 prevents the foreign matter from entering the inside of the hydraulic shock absorber 110 from the outside when the dust lip 102b comes into close contact with the outer peripheral surface of the piston rod 113 with an appropriate tightening allowance. Is to prevent Further, when the pressure of the hydraulic oil increases with the operation of the piston inside the hydraulic shock absorber 110, this hydraulic pressure acts to increase the pressing force of the main lip 101b against the outer peripheral surface of the piston rod 113. Since the main lip 101b is supported by the backup ring 103 from the atmosphere side and the inner periphery side, an increase in the pressing force is suppressed and the pressure resistance is maintained.

JP 2008-309263 A

However, the back-up ring 103 made of synthetic resin has a greater amount of deformation in the direction of diameter reduction as the hydraulic pressure P acting on the main lip 101b of the oil seal 101 becomes higher, so that the main lip 101b cannot be supported. As shown in FIG. 6, the deformation amount of the main lip 101b increases, the friction load on the piston rod 113 increases, and the backup ring 103 itself may come into contact with the outer peripheral surface of the piston rod 113.
Concerned.

  The present invention has been made in view of the above points, and its technical problem is to provide a sealing device capable of maintaining the supporting force of the backup ring with respect to the main lip even when high pressure is applied. There is to do.

  As a means for effectively solving the technical problem described above, the sealing device according to the present invention is formed of a rubber-like elastic material on the sealed space side of the inner diameter portion of the annular substrate, with the shaft facing the sealed space side. A main lip that is in close contact with the outer peripheral surface is provided, and a backup ring that supports the main lip from the atmosphere side and the inner peripheral side is disposed between the inner diameter portion of the annular substrate and the main lip, and the backup ring and the The inner diameter portions of the annular substrates are engaged with each other in the radial direction via the engaging means.

  According to the sealing device of the present invention, even if the pressure of the sealed space acting on the main lip increases, the backup ring that supports the main lip from the atmosphere side and the inner peripheral side is provided with the annular substrate via the engaging means. Since the displacement in the reduced diameter direction is restricted by being radially engaged with the inner diameter portion of the shaft, an increase in the deformation amount of the main lip can be suppressed, and the backup ring itself is also in contact with the outer peripheral surface of the shaft. Therefore, an increase in friction load and wear can be effectively prevented.

It is a half sectional view of the unmounted state which shows a preferred embodiment of a sealing device concerning the present invention by cutting along a plane passing through an axis. It is a half sectional view of the decomposition | disassembly state which cut | disconnects and shows preferable embodiment of the sealing device which concerns on this invention by the plane which passes along an axial center. It is a half sectional view of the mounting state to the hydraulic shock absorber which shows a preferred embodiment of the sealing device according to the present invention by cutting along a plane passing through the axis. It is a half sectional view of the unmounted state which shows an example of the conventional sealing device cut and shown by the plane which passes along an axis. It is a half sectional view of the mounting state to the hydraulic buffer which shows an example of the conventional sealing device cut | disconnected and shown by the plane which passes along an axial center. In an example of the conventional sealing device, the state in which the amount of deformation in the diameter reduction direction of the backup ring is increased is shown by a cut-away side view in a state of being cut along a plane passing through the axis.

  Hereinafter, a preferred embodiment of a sealing device according to the present invention will be described with reference to FIGS. 1 shows an unmounted state, FIG. 2 shows an unmounted state and a disassembled state, and FIG. 3 shows a mounted state on the hydraulic shock absorber.

  First, in FIG. 3, reference numeral 110 is a hydraulic shock absorber in a vehicle suspension system, and includes a cylinder 111, a rod guide 112 attached to the inner periphery near the opening end of the cylinder 111, A piston rod 113 penetrating the peripheral hole is provided. The piston rod 113 corresponds to the shaft described in claim 1.

  The sealing device according to the present invention includes an oil seal 1 that seals hydraulic oil inside the hydraulic shock absorber 110, a dust seal 2 that prevents foreign matter and muddy water from entering, and a backup ring 3.

  Specifically, as shown in FIGS. 1 and 2, the oil seal 1 includes a mounting ring 11 and a sealing space A side that is provided integrally therewith and is an internal space of the hydraulic shock absorber 110 shown in FIG. 3. The dust seal 2 is integrally provided with an annular substrate 21 that is superposed on the side of the mounting ring 11 of the oil seal 1 that is on the atmosphere B side. The dust ring 22 is directed to the atmosphere B side, and the mounting ring 11 of the oil seal 1 and the annular substrate 21 of the dust seal 2 are overlapped with each other and the outer diameter portions are press-fitted to each other.

  The mounting ring 11 of the oil seal 1 is formed by stamping and pressing a metal plate so that a shape (cross-sectional shape shown in the figure) cut along a plane passing through the axis is substantially L-shaped, that is, a disk portion 11a, The outer diameter cylindrical portion 11b extends from the outer diameter end.

  The main lip 12 in the oil seal 1 is vulcanized and bonded to the inner diameter end of the disk portion 11a of the mounting ring 11, and extends so as to gradually become a small diameter toward one side in the axial direction (sealed space A side). The hydraulic oil in the sealed space A is sealed by being slidably brought into close contact with the outer peripheral surface of the rod 113. Further, the outer peripheral lip 13 of the oil seal 1 extends from the base portion vulcanized and bonded to the bent portion between the disk portion 11a and the outer diameter cylindrical portion 11b of the mounting ring 11 to one side in the axial direction (sealed space A side). The hydraulic oil in the sealed space A is sealed by being interposed between the inner surface of the cylinder 111 and the outer peripheral surface of the rod guide 112 in the hydraulic shock absorber 110. An intermediate ridge 15 is formed on the elastic film portion 14 formed continuously between the main lip 12 and the outer peripheral lip 13 and integrally attached to one side surface in the axial direction of the disk portion 11a of the mounting ring 11. Yes. The main lip 12, the outer peripheral lip 13, the elastic film portion 14, and the intermediate ridge 15 are formed by vulcanization molding with a rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity).

  The annular substrate 21 of the dust seal 2 is manufactured by punching a metal plate thicker than the mounting ring 11 of the oil seal 1 into a donut shape, and the other axial side of the disk portion 11a of the mounting ring 11 of the oil seal 1 (main The outer diameter end portion 21a is press-fitted to the inner circumference of the outer diameter cylindrical portion 11b in the mounting ring 11 while being superposed on the surface on the side opposite to the lip 12 and the outer peripheral lip 13). Further, the dust lip 22 is vulcanized and molded from a rubber-like elastic material, and is integrally vulcanized and bonded to the other axial side (atmosphere B side) of the inner diameter portion 21b of the annular substrate 21 to provide an oil seal. 1 extends toward the opposite side of the piston rod 113 and is slidably in close contact with the outer peripheral surface of the piston rod 113 to prevent intrusion of foreign matter, muddy water, and the like in the atmosphere B.

  The backup ring 3 has a suitable rigidity necessary for supporting the main lip 12 of the oil seal 1 and is made of a synthetic resin material having excellent wear resistance and a low friction coefficient. The main lip 12 is disposed between the back surface of the main lip 12 near the base 12a and the inner diameter portion of the annular substrate 21 of the dust seal 2, and supports the main lip 12 from the atmosphere B side and the inner peripheral side to This prevents the main lip 12 from being excessively deformed.

  The inner diameter portion 21b of the annular substrate 21 of the backup ring 3 and the dust seal 2 is engaged with each other in the radial direction via the engaging means.

  Specifically, as shown in FIG. 2, the engagement means of the annular substrate 21 of the backup ring 3 and the dust seal 2 is continuously formed in the circumferential direction on the surface of the inner diameter portion 21 b of the annular substrate 21 on the oil seal 1 side. The engagement concave portion 21c and the engagement convex portion 3a continuously formed in the circumferential direction on the surface of the backup ring 3 facing the inner diameter portion 21b of the annular substrate 21 are engaged with the engagement concave portion 21c. The convex portions 3a are engaged with each other.

  The sealing device of the present invention having the above-described configuration is arranged such that the oil seal 1 faces the sealed space A side and the dust seal 2 faces the atmosphere B side, and the oil seal 1 is integrally fitted with each other in a superposed state. The mounting ring 11 and the annular substrate 21 of the dust seal 2 are sandwiched between the caulking portion 111 a of the cylinder 111 and the rod guide 112 in the hydraulic shock absorber 110.

  The main lip 12 of the oil seal 1 is slidably in close contact with the outer peripheral surface of the piston rod 113 on the inner peripheral side of the rod guide 112, so that the hydraulic oil in the sealed space A is axially rotated. The dust lip 22 in the dust seal 2 is in close contact with the outer peripheral surface of the piston rod 113 so that foreign matter, muddy water, and the like can enter. In the backup ring 3, the inner peripheral surface 3b is held in non-contact with the outer peripheral surface of the piston rod 113, and the portion near the root 12a of the main lip 12 in the oil seal 1 is located on the atmosphere B side and the inner peripheral surface. By supporting from the side, excessive deformation of the main lip 12 due to the hydraulic pressure P in the sealed space A is prevented.

  Further, the elastic film portion 14 and the intermediate protrusion 15 provided on the mounting ring 11 in the oil seal 1 absorb the caulking portion 111a of the cylinder 111 and the error of the caulking load on the mounting ring 11 and the annular substrate 21 by the rod guide 112. And has a sealing function against hydraulic oil.

  Here, when the hydraulic pressure P in the sealed space A rises with the operation of the piston inside the hydraulic shock absorber 110, the hydraulic pressure P acts to increase the pressing force of the main lip 12 against the outer peripheral surface of the piston rod 113. The backup ring 3 acts as a load for reducing the diameter of the backup ring 3 via the main lip 12, but the backup ring 3 is formed by engagement means constituted by fitting the engagement convex portion 3a and the engagement concave portion 21c to each other. Since it is engaged with the annular substrate 21 of the dust seal 2 in the radial direction, displacement in the reduced diameter direction is restricted. For this reason, an increase in the deformation amount of the main lip 12 is effectively suppressed, and the backup ring 3 itself is also prevented from contacting the outer peripheral surface of the piston rod 113, so that an increase in friction load and an increase in wear are effectively prevented. be able to.

  In the embodiment described above, the mounting ring 11 of the oil seal 1 provided integrally with the main lip 12 and the outer peripheral lip 13 and the annular substrate 21 of the dust seal 2 provided integrally with the dust lip 22 are fitted and integrated with each other. However, the present invention is also applicable to the case where the main lip 12 and the outer peripheral lip 13 are integrally provided on one side of the annular substrate 21 in the axial direction and the dust lip 22 is integrally provided on the other side of the annular substrate 21 in the axial direction. be able to.

  Further, the engagement means between the backup ring 3 and the dust seal 2 is not limited to the engagement convex portion 3a and the engagement concave portion 21c as shown in the illustrated example. It can also be reversed from the example shown.

DESCRIPTION OF SYMBOLS 1 Oil seal 11 Mounting ring 12 Main lip 2 Dust seal 21 Annular substrate 21c Engagement recessed part (engagement means)
22 Dustrip 3 Backup ring 3a Engaging projection (engaging means)
110 Hydraulic shock absorber 111 Cylinder 112 Rod guide 113 Piston rod (shaft)

Claims (1)

  A main lip made of a rubber-like elastic material and being in close contact with the outer peripheral surface of the shaft in a state of facing the sealed space side is provided on the sealed space side of the inner diameter portion of the annular substrate. The backup ring to be supported is disposed between the inner diameter portion of the annular substrate and the main lip, and the inner diameter portion of the backup ring and the annular substrate are engaged with each other in the radial direction via the engaging means. Sealing device characterized.

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