JP2005351441A - Seal structure for hydraulic shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seal structure for a hydraulic shock absorber which does not cause a failure in sealing resulting from the assembling operation at the time of assembling the absorber. <P>SOLUTION: In the seal structure for a hydraulic shock absorber, an outer tube 3 and an inner tube 2 are concentrically arranged, a rod guide 5 to guide a piston rod 4 in a slidable manner is provided between an inner periphery of an opening end of the outer tube 3 and an opening end of the inner tube 2, the rod guide 5 being provided with a lip reception inclined surface 9a on its outer peripheral portion, and an oil seal 6 is mounted on an upper surface of the rod guide 5. The oil seal 6 includes an annular inner peripheral lip 16 which seals the outer peripheral surface of the piston rod 4 in slide contact therewith, and a similar annular outer peripheral lip 18 for sealing the inner peripheral surface of the outer tube 3. The outer lip 18 is inserted in a space defined by the lip reception inclined surface 9a and the outer tube 3 in such a state that it is elastically deformed. The outer peripheral lip 18 of the oil seal 6 is provided with a deformation inhibition means 19 which inhibits the lip 18 from being deformed in the diameter-expansion direction until predetermined load is applied to the outer peripheral lip 18 when it is inserted in the space along the lip reception inclined surface 9a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a seal structure for a hydraulic shock absorber used in a suspension device such as an automobile.

  Conventionally, as a sealing structure of this type of hydraulic shock absorber, the one shown in Patent Document 1 can be exemplified.

  That is, as shown in FIG. 6, a rod guide 5 for slidably guiding the piston rod 4 is provided between the opening end of the inner tube 2 and the inner periphery of the opening end of the outer tube 3, and this rod guide An oil seal 6 is placed on the upper surface of the outer tube 5, and the outer tube 3, the oil seal 6 and the rod guide 5 are integrally crimped and fixed by bending the upper end portion of the outer tube 3 inward.

  A high pressure gas G is sealed in a reservoir chamber R formed between the inner periphery of the outer tube 3 and the outer periphery of the inner tube 2.

  The rod guide 5 is formed by press-molding a single metal plate, and the outer peripheral surface is press-fitted into the inner peripheral surface of the inner tube 2. Similarly, the outer peripheral surface is formed on the inner peripheral surface of the outer tube 3. The outer support portion 9 to be press-fitted and the support portions 8 and 9 are connected to each other, and a connecting portion 12 that contacts the opening end portion of the inner tube 2 on the lower surface and positions the rod guide 5 is provided.

  Further, the inner support portion 8 has a guide hole 10 for guiding the piston rod 4 on the inner peripheral surface thereof, and a wear-resistant annular bush 11 press-fitted into the guide hole 10. The piston rod 4 is slidably guided.

  The connecting portion 12 is provided with an annular protrusion 13 on the outer peripheral portion of the upper surface, and the oil seal 6 is mounted on the rod guide by placing an insert metal 17 (described later) of the oil seal 6 on the upper surface of the protrusion 13. 5 is positioned at a regular position.

  The outer support portion 9 is formed with a lip storage inclined surface 9a inclined upward inward on the upper outer peripheral surface thereof, and will be described later in a space formed by the inclined surface 9a and the inner peripheral surface of the outer tube 3. The outer peripheral lip 18 of the oil seal 6 is inserted and arranged in an elastically deformed state.

  The oil seal 6 includes an inner peripheral lip 16 including an annular dust strip 14 and an oil lip 15 slidably contacting the outer periphery of the piston rod 4, an insert metal 17 integrally formed with the inner peripheral lip 16, and an outer periphery of the insert metal 17. It is comprised from the cyclic | annular outer periphery lip 18 integrally formed in the side lower surface.

The outer peripheral lip 18 is inserted and disposed in an elastically deformed state in the space by moving downward along the lip storage inclined surface 9a at the time of assembly. By elastically contacting the lip storage inclined surface 9a, the gap between the inner peripheral surface of the outer tube 3 and the outer peripheral surface of the oil seal 6 is sealed so that the high-pressure gas G in the reservoir chamber R does not leak to the atmosphere side. ing.
JP 2003-343633 A (FIGS. 1 and 3)

  In the seal structure of the hydraulic shock absorber configured as described above, there is no particular problem. However, when the following assembly process is employed, problems unique to this process can be considered.

  In this assembling process, first, the oil seal 6 is temporarily attached to the upper surface of the rod guide 5 into which the piston rod 4 is inserted so that only the distal end portion of the outer peripheral lip 18 abuts the lip storage inclined surface 9 a of the rod guide 5. Attach the seal assembly.

  Next, as shown in FIG. 7, the seal assembly is placed above the normal position between the opening end of the inner tube 2 and the inner periphery of the opening end of the outer tube 3, that is, the outer peripheral lip 18 of the rod guide 5. Is inserted and temporarily assembled so as to be exposed above the opening end of the outer tube 3.

  In this state, the reservoir is formed between the opening end of the outer tube 3 and the outer peripheral lip 18 and a slight gap formed between the inner peripheral surface of the outer tube 3 and the outer peripheral surface of the outer support portion 9 of the rod guide 5. The chamber R is filled with the high pressure gas G.

  When the filling of the high pressure gas G is completed, the seal assembly is connected to the normal position between the open end of the inner tube 2 and the inner periphery of the open end of the outer tube 3, that is, the open end of the inner tube 2 It is lowered until it contacts the lower surface of the part 12.

  Specifically, a jig (not shown) is brought into contact with the upper surface of the insert metal 17 of the oil seal 6 to lower the insert metal 17, and after the lower surface of the insert metal 17 comes into contact with the protrusion 13 of the rod guide 5. The oil seal 6 is lowered until the opening end of the inner tube 2 comes into contact with the lower surface of the connecting portion 13 of the rod guide 5 in a state where the oil seal 6 is assembled at a proper position with respect to the rod guide 5.

  As the oil seal 6 is lowered, the outer peripheral lip 18 in a state where only the end portion is in contact with the inclined surface 9a for lip storage is lowered along the inclined surface 9a, and the diameter is increased toward the tip side. By being elastically deformed, the inner peripheral surface of the outer peripheral lip 18 is brought into pressure contact with the lip storage inclined surface 9a of the rod guide 5 and the outer peripheral surface is pressed against the inner peripheral surface of the outer tube 3 to seal the respective contact portions.

  Thereafter, the outer tube 3, the oil seal 6 and the rod guide 5 are integrally crimped and fixed by bending the upper end portion of the outer tube 3 inward.

  In the above-described series of assembly steps, the filling operation of the high-pressure gas G is also performed at the same time. To do.

  In this temporarily assembled state, since the outer peripheral lip 18 of the oil seal 6 is located above the opening end of the outer tube 3, the lowering operation of the oil seal 6 performed in the lowering process of the seal assembly is performed by the lip. A seal against the outer tube 3 so that the distal end of the outer peripheral lip 18 descending along the storage inclined surface 9a enters the outer tube 3 before elastically deforming to a larger diameter than the inner peripheral surface of the outer tube 3 If the temporary assembly position of the assembly is not set, the outer peripheral lip 18 may come into contact with the opening end of the outer tube 3 during the lowering operation of the oil seal 6 and the outer peripheral lip 18 may be damaged.

  Therefore, it is necessary to perform this position setting work carefully, and the work time is increased, the assembling cost is increased, and if the outer peripheral lip 18 is damaged, it may be assumed that it causes a sealing failure. .

  Therefore, the present invention was devised to solve the above problems, and its purpose is to provide a seal structure for a hydraulic shock absorber that does not cause a seal failure due to the assembly operation during the assembly operation. Is to provide.

  In order to achieve the above object, according to the present invention, an outer tube and an inner tube are arranged concentrically, and a piston rod is slidable between the inner periphery of the outer end of the outer tube and the inner end of the inner tube. A rod guide for guiding is provided, and an inclined surface for storing the lip is provided on the outer periphery of the rod guide, and an oil seal is placed on the upper surface of the rod guide, and the oil seal is in sliding contact with the outer peripheral surface of the piston rod. An annular inner peripheral lip that seals and an annular outer peripheral lip that seals the inner peripheral surface of the outer tube by being elastically deformed and inserted into the space formed by the inclined surface for storing the lip and the outer tube. In the seal structure of the hydraulic shock absorber provided with the outer peripheral lip of the oil seal, the outer peripheral lip is spaced along the inclined surface for storing the lip. When it is inserted, until a predetermined load is applied it is characterized in the provision of the deformation preventing means for preventing the deformation to its diameter direction.

  According to the present invention, when the outer peripheral lip is inserted into the outer peripheral lip along the inclined surface for storing the lip, the deformation preventing means for preventing the deformation in the expanding direction until a predetermined load is applied. For example, the seal assembly is configured by temporarily assembling the oil seal on the upper surface of the rod guide so that only the tip of the outer peripheral lip contacts the inclined surface for storing the lip of the rod guide. When assembling the seal structure by lowering the solid body to a normal position between the opening end of the inner tube and the inner periphery of the opening end of the outer tube, the following excellent effects are exhibited.

  That is, until the predetermined load is applied by the deformation preventing means, the outer peripheral lip does not descend along the lip storing inclined surface during the lowering operation. By descending along the outer peripheral lip, the diameter of the outer peripheral lip expands, and the possibility that the outer peripheral lip is damaged by coming into contact with the opening end of the outer tube and causing poor sealing can be reliably wiped off.

  In the following, an embodiment in which the present invention is embodied in a seal structure for a hydraulic shock absorber used in an automobile suspension device will be described with reference to the drawings. This seal structure is basically shown in a conventional example. Since the structure is the same as that described above, the same members will be described with the same reference numerals.

  As shown in FIG. 1, the outer tube 3 and the inner tube 2 are disposed concentrically, and the piston rod 4 is disposed between the opening end of the inner tube 2 and the inner periphery of the opening end of the outer tube 3. A rod guide 5 that is slidably guided is provided. An oil seal 6 is placed on the upper surface of the rod guide 5, and the outer tube 3, the oil seal 6 and the outer tube 3 are bent by bending the upper end of the outer tube 3 inward. The rod guide 5 is integrally crimped and fixed.

  A high pressure gas G is sealed in a reservoir chamber R formed between the inner periphery of the outer tube 3 and the outer periphery of the inner tube 2.

  More specifically, the rod guide 5 is formed by press-molding a single metal plate, and the inner support portion 8 whose outer peripheral surface is press-fitted into the inner peripheral surface of the inner tube 2 and the outer peripheral surface are also the same. The outer support portion 9 press-fitted into the inner peripheral surface of the outer tube 3 and the support portions 8 and 9 are connected to each other, and the connecting portion 12 that contacts the opening end portion of the inner tube on the lower surface to position the rod guide 5; It has.

  Further, the inner support portion 8 has a guide hole 10 for guiding the piston rod 4 on the inner peripheral surface thereof, and a wear-resistant annular bush 11 press-fitted into the guide hole 10. The piston rod 4 is slidably guided.

  The connecting portion 12 is provided with an annular protrusion 13 on the outer peripheral portion of the upper surface, and the oil seal 6 is mounted on the rod guide by placing an insert metal 17 (described later) of the oil seal 6 on the upper surface of the protrusion 13. 5 is positioned at a regular position.

  The outer support portion 9 is formed with a lip storage inclined surface 9a inclined upward inward on the upper outer peripheral surface thereof, and will be described later in a space formed by the inclined surface 9a and the inner peripheral surface of the outer tube 3. The outer peripheral lip 18 of the oil seal 6 is inserted and arranged in an elastically deformed state.

  The oil seal 6 includes an inner peripheral lip 16 including an annular dust strip 14 and an oil lip 15 slidably contacting the outer periphery of the piston rod 4, an insert metal 17 integrally formed with the inner peripheral lip 16, and an outer periphery of the insert metal 17. It is comprised from the cyclic | annular outer periphery lip 18 integrally formed in the side lower surface.

  The outer peripheral lip 18 is formed in a cylindrical shape extending downward, and a concave portion 19 as a deformation preventing means of the present invention is provided at a contact portion of the tip portion with the inclined surface as shown in FIG. Is provided.

  As shown in FIG. 3, the concave portion 19 is formed in a trapezoidal cross section composed of an inclined surface-shaped enlarged diameter portion 20 that expands toward the outside and a central flat surface portion 21, and is caused by its own elastic force. A so-called sucker action is achieved.

  The recesses 19 are integrally formed when the outer peripheral lip 18 is formed, and a plurality of the recesses 19 are provided at predetermined intervals over the entire periphery of the distal end of the outer peripheral lip 18 as shown in FIG.

  Therefore, when the oil seal 6 is arranged so that the tip end of the outer peripheral lip 18 abuts the lip storage inclined surface 9 a of the rod guide 5, the oil seal 6 is moved to the rod guide 5 by the suction action of the recess 19 provided at the tip portion. The outer peripheral lip 18 does not move downward along the lip storage inclined surface 9a unless an external force exceeding the fixing force generated by the suction cup action is applied.

  The outer peripheral lip 18 is inserted and arranged in a state of being elastically deformed in the space by moving downward along the lip storage inclined surface 9a, and the outer peripheral lip 18 and the rod guide 5 By elastically contacting the lip storage inclined surface 9a, the gap between the inner peripheral surface of the outer tube 3 and the outer peripheral surface of the oil seal 6 is sealed so that the gas G in the reservoir chamber R does not leak to the atmosphere side. Yes.

  In order to assemble the seal structure of the hydraulic shock absorber configured as described above, first, the oil seal 6 is formed on the top surface of the rod guide 5 into which the piston rod 4 is inserted, and the recess 19 is formed at the tip of the outer peripheral lip 18. Is brought into contact with the inclined surface 9a for lip storage of the rod guide 5 so as to be fixed by a sucker action to constitute a seal assembly in a temporarily assembled state.

  Next, the seal assembly is placed above the normal position between the opening end of the inner tube 2 and the inner periphery of the opening end of the outer tube 3, that is, as shown in FIG. Is inserted and temporarily assembled so as to be positioned above the opening end of the outer tube 3.

  In this state, the reservoir is formed between the opening end of the outer tube 3 and the outer peripheral lip 18 and a slight gap formed between the inner peripheral surface of the outer tube 3 and the outer peripheral surface of the outer support portion 9 of the rod guide 5. The chamber R is filled with the high pressure gas G.

  When the filling of the high pressure gas G is completed, a jig (not shown) is brought into contact with the insert metal 17 of the oil seal 6 constituting the seal assembly, and the insert metal 17 is pressed downward to thereby remove the seal assembly. The lower surface of the connecting portion 12 of the rod guide 5 is lowered to a proper position where it contacts the open end of the inner tube 2.

  At this time, the oil seal 6 is fixed to the lip storage inclined surface 9a by the sucking action of the recess 19 as a deformation preventing means provided on the outer peripheral lip 18, so that the fixing force by the sucking action is exceeded. Unless an external force is applied to the oil seal 6, the oil seal 6 does not descend along the inclined surface 9a.

  For this reason, when the pressing force of the seal assembly by the jig is set to be smaller than the fixing force by the suction cup action, the outer peripheral lip 18 does not descend along the lip storage inclined surface 9a. It is said that even if the temporary assembly position of the seal assembly with respect to the outer tube 3 is not set accurately, the outer peripheral lip 18 comes into contact with the opening end of the outer tube 3 and is damaged by the outer peripheral lip 18. The fear can be surely wiped out.

  Therefore, in this case, it is not necessary to spend time for the temporary assembly position setting operation of the seal assembly with respect to the outer tube 3, and the operation time can be shortened and the assembly cost can be reduced.

  In this case, the jig is set with a stroke amount so that the seal assembly descends to a proper position where the lower surface of the connecting portion 12 of the rod rod guide 5 contacts the opening end of the inner tube 2. Even after the lower surface of the connecting portion 12 comes into contact with the opening end of the inner tube 2, the insert metal 17 is pressed until the outer peripheral lip 18 and the inclined surface 9a for storing the lip are released, and the both are fixed. It comes to remove.

  Even when the pressing force of the seal assembly by the jig is set to be larger than the fixing force due to the suction cup action, until the outer peripheral lip 18 is detached from the lip storage inclined surface 9a, the lip storage inclined surface 9a is followed. Since it does not descend, the temporary assembly position of the seal assembly relative to the outer tube 3 can be set with a margin for the time lag until the outer peripheral lip 18 is removed.

  Therefore, even in this case, it is possible to surely wipe away the fear that the outer peripheral lip 18 contacts the opening end of the outer tube 3 and damages the outer peripheral lip 18 to cause a seal failure. It is not necessary to spend much time for the temporary assembly position setting operation of the attachment, and the work time can be shortened and the assembly cost can be reduced.

  As described above, in the present embodiment, it is possible to reliably prevent the outer peripheral lip 18 of the oil seal 6 from coming into contact with the opening end portion of the outer tube 3 and being damaged due to the lowering process of the seal assembly. In addition, since it is not necessary to spend time for the temporary assembly position setting operation of the seal assembly with respect to the outer tube 3, the assembly operation can be facilitated and the assembly cost can be reduced.

  Further, since the concave portion 18 that functions as a suction preventing means as the deformation preventing means is formed integrally with the outer peripheral lip 18, it can be realized at low cost and easily.

  In addition, this invention is not limited to said embodiment, For example, it can also be changed and actualized as follows.

  1) In the present embodiment, the recess 19 that functions as a suction preventing means is integrally formed with the outer peripheral lip 18, but the present invention is not limited to this, and as shown in FIG. You may make it serve as a deformation | transformation prevention means by setting it as the reverse cone-shaped outer peripheral lip 22 to which diameter reduction is carried out.

Also in this case, since the outer peripheral lip 22 is not easily deformed in the diameter-expanding direction by its own elastic force, the same effect as that of the concave portion 19 is exhibited.

Further, the recess 19 may be provided in the outer peripheral lip 22.

  2) In the present embodiment, the rod guide 5 is formed by press-molding a single metal plate. However, the rod guide 5 is not limited to this and is formed by sintering or the like. A guide may be used.

  In the present embodiment, the seal structure of the hydraulic shock absorber used in the suspension device of the automobile is shown. However, the present invention is not limited to this, and the seal structure of a general hydraulic shock absorber may be embodied.

It is principal part sectional drawing which actualized this invention to the seal structure of the hydraulic shock absorber. In FIG. 1, it is principal part sectional drawing which shows the seal assembly body which mounted the oil seal in the rod guide. It is a principal part expanded sectional view which shows the recessed part of FIG. It is a top view which shows the recessed part of FIG. It is a principal part expanded sectional view which shows another example of this invention. It is principal part sectional drawing which shows a prior art example. In FIG. 6, it is principal part sectional drawing which shows the seal assembly body which mounted the oil seal in the rod guide.

Explanation of symbols

2 Inner tube 3 Outer tube 4 Piston rod 5 Rod guide 6 Oil seal 9a Inclined surface for lip storage 16 Inner lip 18 Outer lip 19 Recess (deformation preventing means)
22 Outer lip that also serves as a deformation prevention means

Claims (3)

The outer tube and the inner tube are arranged concentrically, and a rod guide is provided between the inner periphery of the outer tube open end and the inner tube open end to slidably guide the piston rod. A lip storage inclined surface is provided on the outer peripheral portion, and an oil seal is placed on the upper surface of the rod guide. The oil seal is slidably in contact with the outer peripheral surface of the piston rod and sealed, and the lip In a hydraulic shock absorber sealing structure provided with an annular outer peripheral lip that is inserted in a state of being elastically deformed into a space formed by an inclined surface for storage and an outer tube and seals the inner peripheral surface of the outer tube. A predetermined load is applied to the outer peripheral lip of the seal when the outer peripheral lip is inserted into the space along the inclined surface for storing the lip. In the sealing structure of a hydraulic shock absorber which characterized in that a deformation prevention means for preventing deformation to its diameter direction. The deformation preventing means is a concave portion having a suction cup function provided at a contact portion with the inclined surface for lip storage at the front end portion of the outer peripheral lip, and a plurality of deformation preventing means are provided at predetermined intervals over the entire circumference of the outer peripheral lip. The seal structure of the hydraulic shock absorber according to claim 1. 2. The seal structure for a hydraulic shock absorber according to claim 1, wherein the outer peripheral lip is formed in an inverted conical shape having a diameter reduced toward the tip and serves also as a deformation preventing means.

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