JPH0665638U - Oil buffer structure of hydraulic shock absorber - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the assembling property and the sealing property of the oil seal incorporated in the hydraulic shock absorber. [Structure] An annular recess 11 forming a part of a return passage of a rod guide 3 on the outer peripheral side of a metal reinforcing ring 14 of an oil seal 4.
An outer peripheral lip portion 21 facing inside and contacting the inner peripheral surface of the outer tube 1 and an annular seal portion 22 contacting the inner peripheral surface of the outer tube 1 are provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an oil seal structure in a hydraulic shock absorber in which a piston rod is inserted into an outer tube via an oil seal and a rod guide.

[0002]

[Prior art]

 Conventionally, as an oil seal structure of a hydraulic shock absorber, there is one disclosed in Japanese Utility Model Publication No. 4-105648. This will be described with reference to FIG. 4. The piston rod 104 is inserted into the outer tube 101 from above through the oil seal 102 and the rod guide 103, and the oil seal 102 is inserted into the reinforcing ring support portion 106 of the rod guide 103. And the lower end of the rod guide 103 holds the upper end of the damper cylinder 107.

Then, communication paths 108 and 109 that form return flow paths are formed on the upper surface of the reinforcing ring support portion 105 of the rod guide 103 and on the outer peripheral surface of the rod guide 103, respectively, to connect the rod guide 103 and the oil seal 102. The hydraulic oil flowing in between is returned to the reservoir chamber 110 via these communication passages 108 and 109.

The oil seal 102 has a seal member 112 fixed to a flat metal reinforcing ring 111, and the seal member 112 has a lip portion slidably contacting the inner peripheral side of the reinforcing ring 111 with the outer peripheral surface of the piston rod 104. The outer tube 113, 114 is provided with a check lip portion 115 that abuts against the stepped portion 103a of the rod guide 103 on the lower surface side and an annular recess 116 between the communication passage 108 and the communication passage 109 of the rod guide 103 on the outer peripheral surface. The outer peripheral lip portion 117 is formed so as to contact the inner peripheral surface of the inner peripheral surface 101 with a tightening margin.

[0005]

[Problems to be solved by the device]

 However, in the oil seal structure described above, the outer peripheral lip of the oil seal has a tightening margin for the outer tube, and therefore, when the oil seal is inserted into the outer tube in the assembly process, The lip may get caught in the outer tube end and be damaged. Further, when the outer peripheral lip portion of the oil seal is deteriorated due to deterioration over time, the outer peripheral lip portion may wrap around the annular recess of the rod guide and the tightening margin may be lost so that the sealing performance may be lost.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides an outer peripheral lip portion which faces an annular recess forming a return passage formed in a rod guide and abuts an inner peripheral surface of an outer tube on an outer peripheral portion of an oil seal, and an inner peripheral surface of the outer tube. An annular seal portion that abuts the surface is provided.

[0007]

[Action]

 Since the oil seal is provided with an outer peripheral lip and an annular seal, when the sealing performance of the outer peripheral lip decreases, it can be compensated for by the annular lip and each tightening margin can be dispersed. It is possible to improve the attaching property and the sealing property.

[0008]

【Example】

 Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a sectional view of an essential part of a hydraulic shock absorber to which the oil seal structure according to the present invention is applied, FIG. 2 is a sectional view of the oil seal of the shock absorber, and FIG. 3 is a plan sectional view of the oil seal. .

Inside the outer tube 1 of the hydraulic shock absorber, a damper cylinder 2 is erected so that its upper end is held by a rod guide 3, and the damper cylinder 2 is fitted onto the inner peripheral surface of the outer tube 1 from above. The piston rod 5 is inserted through the oil seal 4 and the rod guide 3 described above, and the oil seal 4 is held by being sandwiched between the rod guide 3 and the end plate 6.

A bush 7 that is in sliding contact with the outer peripheral surface of the piston rod 5 is fitted on the inner peripheral surface of the rod guide 3, and a holding portion 8 that holds the lower surface of the oil seal 4 is formed on the upper portion. A communicating groove 9 is formed on the outer peripheral surface of the rod guide 3, and an annular recess 11 is provided between the communicating groove 9 and the communicating groove 10, whereby the rod guide 3 and the oil seal 4 are connected. A return flow path is provided for returning the hydraulic oil flowing into the reservoir chamber 12 to the reservoir chamber 12.

As shown in FIG. 2, the oil seal 4 is formed by fixing a seal member 15 to a plate-shaped metal reinforcing ring 14, and the seal member 15 has a piston rod on the inner peripheral side of the metal reinforcing ring 14. 5. Two lip parts 16 and 17 which are in sliding contact with the outer peripheral surface are formed, and tightening rings 18 and 19 are provided on the outer peripheral sides of these lip parts 16 and 17, and a rod is provided on the lower surface side of the metal reinforcing ring 14. A check lip portion 20 is formed that abuts the step portion 3a of the guide 3.

Further, an outer peripheral lip that faces the outer peripheral surface of the metal reinforcing ring 14 of the oil seal 4 inside the annular recess 11 of the rod guide 3 and abuts the inner peripheral surface of the outer tube 1 with a tightening margin. In addition to forming the portion 21, an annular seal portion 22 is formed to be in contact with the inner peripheral surface of the outer tube 1 with a tight margin. Here, a plurality of recesses 24 are formed in the outer peripheral portion of the metal reinforcing ring 14 as shown in FIG. 3 to compensate for the lack of volume of the annular seal portion 22.

With the above-described structure, the outer peripheral lip portion 21 and the annular seal portion 22 of the oil seal 4 seal the inner peripheral surface of the outer tube 1. Therefore, the outer peripheral lip portion 21 and the annular seal portion 22 are tightened. The cost can be dispersed to the extent that the sealability is not impaired, the assemblability is improved, and the sealability can be maintained by the annular lip portion 22 even when the sealability of the outer peripheral lip portion 21 is reduced.

[0014]

[Effect of device]

 As described above, according to the present invention, since the outer peripheral lip portion and the annular seal portion are provided on the outer peripheral portion of the oil seal, when the sealing performance of the outer peripheral lip portion is deteriorated, the annular lip portion can compensate. At the same time, the respective tightening margins can be dispersed, and the assembling property and the sealing property can be improved. In addition, by forming the concave portion on the outer peripheral portion of the metal reinforcing ring, it is possible to compensate for the lack of volume of the annular seal portion.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a hydraulic shock absorber to which an oil seal structure according to the present invention is applied.

FIG. 2 is an enlarged sectional view of an oil seal of the shock absorber.

FIG. 3 is a plan sectional view of the oil seal.

FIG. 4 is a sectional view of a main part of a hydraulic shock absorber to which a conventional oil seal structure is applied.

[Explanation of symbols]

1 ... Outer tube, 2 ... Damper cylinder, 3 ... Rod guide, 4 ... Oil seal, 5 ... Piston rod, 11
... annular recess forming part of the return flow path, 14 ... metal reinforcing ring,
15 ... Seal member, 21 ... Peripheral lip part, 22 ... Annular seal part, 24 ... Recessed part of metal reinforcing ring.

Front page continuation (72) Yutaka Sato Inventor Yutaka Sato 1-1-14 Fujiwara-cho, Gyoda-shi, Saitama Inside the Saitama Head Office Factory, Showa Seisakusho Co., Ltd. (72) Tsuneo Mochizuki 3-30-1 Horikiri, Katsushika-ku, Tokyo Stock Association Arai Factory

Claims (2)

[Scope of utility model registration request] 1. In a hydraulic shock absorber in which a piston rod is inserted into an outer tube via an oil seal and a rod guide, the oil seal faces an annular recess forming a return flow passage formed in the rod guide on an outer peripheral portion. An oil seal structure for a hydraulic shock absorber, further comprising an outer peripheral lip portion abutting on the inner peripheral surface of the outer tube and an annular seal portion abutting on the inner peripheral surface of the outer tube. 2. The oil for a hydraulic shock absorber according to claim 1, wherein the oil seal includes a flat metal reinforcing ring, and a plurality of recesses are formed on an outer peripheral portion of the flat metal reinforcing ring. sticker.