JPH09229124A - Oil seal structure of hydraulic damper and its gas enclosing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enclose a gas with no risk of damaging a dust lip part. SOLUTION: A cap 52 equipped with a gas flow-path 58 to serve as a gas encapsulating path is previously mounted in a part of an oil seal 30 on the side with a dust lip part 40. This eliminates necessity for a part of a gas enclosing jig to be inserted between the dust lip part 40 and the periphery of a piston rod 16 against the energizing force of a spring 48 at the time of gas enclosure so that the dust lip 40 is precluded from being damaged. The cap 52 is removed from the oil seal 30 after enclosing of the gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil seal structure for a hydraulic shock absorber and a gas filling method for the hydraulic shock absorber.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 56-42733 discloses an oil seal structure in a twin-tube type gas-filled shock absorber and a gas charging method using the oil seal structure. The oil seal structure and gas filling method disclosed in this publication will be described below.

First, the oil seal structure will be described. As shown in FIG. 10, the shock absorber 15
0 comprises an outer tube 152 and a cylinder tube 154 arranged concentrically. At the upper end of the cylinder tube 154, the small diameter portion 15 of the rod guide 156 is provided.
6A is fitted. A bush 158 is press-fitted into the shaft center portion of the small diameter portion 156A.
A piston rod 160 having a piston at its tip is movably arranged inside. Also, the rod guide 156
A communication passage 162 is formed in the large diameter portion 156 </ b> B so as to extend obliquely in the thickness direction. As a result, the reservoir chamber 164 formed between the outer tube 152 and the cylinder tube 154 is communicated with the oil chamber 166 formed above the large diameter portion 156B. The large diameter portion 15
6B is arranged in contact with the inner peripheral surface of the outer tube 152.

An oil seal assembly 168 is arranged at the upper end of the outer tube 152. The oil seal assembly 168 includes a main body 170 screwed onto the upper end of the outer tube 152, a seal member 172 fixed to the axial center of the main body 170,
Consists of Further, the sealing member 172 includes the dust lip portion 174 disposed on the upper side and the dust lip portion 1
The main lip portion 176 is integrally formed with the main lip 74 and is disposed on the lower side. It should be noted that annular springs 178 and 180 are provided on the outer peripheral portions of the dust lip portion 174 and the main lip portion 176, respectively, whereby both the dust lip portion 174 and the main lip portion 176 are attached to the outer peripheral surface of the piston rod 160. Pressed.

Next, the structure of the jig 182 used when gas is filled in the shock absorber 150 having the above-mentioned oil seal structure will be briefly described.

The jig 182 has a housing 184 which is fitted in the outer tube 152. An O-ring 186 is fitted on the inner peripheral surface of the tip of the housing 184. A passage 188 into which the upper end of the piston rod 160 is inserted is formed in the axial center of the housing 184, and a gas filling hole 190 is formed in the bottom of the passage 188. Further, from the outer peripheral portion of the passage 188 of the housing 184, a thin cylindrical insertion portion 192 is formed.
Are extended together. On the inner peripheral surface of the insertion portion 192, a plurality of grooves 194 having the longitudinal direction in the axial direction are formed in the circumferential direction.

Next, a gas filling method using the above-mentioned jig 182 will be described. First, the housing 184 of the jig 182 is fitted onto the upper end portion of the outer tube 152. As a result, the inner peripheral surface of the distal end portion of the housing 184 and the outer peripheral surface of the outer tube 152 are sealed by the O-ring 186, and the insertion portion 192 resists the biasing force of the spring 178 and the insertion portion 192 of the dust lip portion 174 and the piston rod 160. The dust lip portion 174 is inserted between the outer peripheral surface and the outer peripheral surface and the diameter thereof is expanded. Next, the gas is supplied into the passage 188 from the gas charging hole 190. The supplied gas is supplied from the passage 188 to the main lip portion 176 side through the groove 194 of the insertion portion 192. Therefore, the main lip portion 176 is expanded in diameter against the biasing force of the spring 180 to form a gap with the outer peripheral surface of the piston rod 160. As a result, the supplied gas is supplied to the main lip portion 17
It is supplied into the reservoir chamber 164 from the 6 side via the oil chamber 166 and the communication passage 162. After gas supply, jig 182
Of the dust lip portion 174 by the urging force of the spring 178.
Is pressed against the outer peripheral surface of the piston rod 160, and the gas filling work is completed.

[0008]

However, according to the configuration disclosed in the above publication, the insertion portion 19 of the jig 182 is resisted against the urging force of the spring 178 at the time of gas filling.
2 must be inserted between the dust lip portion 174 and the outer peripheral surface of the piston rod 160, so that the dust lip portion 174 can be damaged by the insertion portion 192 at this time.

In view of the above facts, an object of the present invention is to obtain an oil seal structure of a hydraulic shock absorber capable of sealing gas without damaging the dust lip portion and a gas filling method for the hydraulic shock absorber. .

[0010]

According to a first aspect of the present invention, an elastic member is assembled between an upper end side of a cylindrical body and an outer peripheral surface of a piston rod which is axially movable in the cylindrical body. An oil seal structure of a hydraulic shock absorber, comprising an oil seal including a dust lip portion and a main lip portion, which are made of a material and are pressed against the outer peripheral surface of a piston rod by an urging force, and are provided in the oil seal. When the oil seal is assembled, a gas filling path is formed between the dust lip portion arranged on the outer side of the main lip portion of the cylinder and the outer peripheral surface of the piston rod, and after the gas filling, the oil seal is formed. It is characterized in that it has a means for forming a gas enclosing path that can be removed from.

According to a second aspect of the present invention, in the first aspect of the present invention, an annular holding portion that is inserted into the piston rod and is held at an end portion of the piston rod, and the holding portion are integrally formed. A first connecting portion that extends and is connected to the inner peripheral portion of the oil seal and that breaks due to a first predetermined load that acts when the holding portion is inserted into the piston rod, and extends integrally from the holding portion. A projecting member configured to include a second connecting portion that is ejected and is connected to an inner peripheral portion of the oil seal, and that is broken by a second predetermined load larger than the first predetermined load. The gas filling path forming means is constituted by the above.

A gas filling method for a hydraulic shock absorber according to a third aspect of the present invention is applied to a hydraulic shock absorber provided with an oil seal according to the first or second aspect, and the gas filling path forming means is provided. A first step of assembling the provided oil seal between the upper end side of the cylindrical body and the outer peripheral surface of the piston rod that is arranged so as to be axially movable inside the cylindrical body, and the gas sealing passage forming means. It is characterized by including a second step of filling the gas into the cylinder from the gas filling passage and a third step of removing the gas filling passage forming means from the oil seal after the gas filling.

According to the first aspect of the present invention, when the oil seal is assembled between the upper end side of the cylindrical body and the outer peripheral surface of the piston rod, the gas sealing passage formed in the oil seal is formed. By the means, a gas charging passage is formed between the dust lip portion arranged on the outside of the main body of the cylinder and the outer peripheral surface of the piston rod. Therefore, when the gas is filled in the cylinder, it is possible to fill the gas using this gas filling path. Note that, after the gas is filled, the gas filled path forming means is removed from the oil seal. As a result, the dust lip portion and the main lip portion of the oil seal are pressed against the outer peripheral surface of the piston rod by the urging force.

As described above, according to the present invention, since the gas sealing passage forming means is provided in the oil seal, a part of the jig is placed between the dust lip portion and the outer peripheral surface of the piston rod against the biasing force at the time of gas sealing. There is no need to insert it in.

According to the present invention described in claim 2, claim 1
In the invention described above, the gas injection path forming means is constituted by a projecting member including a holding portion and a first connecting portion and a second connecting portion, and the first connecting portion and the second connecting portion. It is possible to form the gas charging passage and to remove the gas charging passage forming means after the gas charging by utilizing the difference in the breaking load set in the portion, and it is possible to seal the gas in the cylinder.

That is, in the state before the protrusion member is attached to the piston rod, the protrusion member is configured as a part of the oil seal via the first connecting portion and the second connecting portion. Then, first, the holding portion of the projecting member is inserted into the piston rod to hold it at the end portion of the piston rod. At this time, the first connecting portion is broken by the first predetermined load that acts when the holding portion is inserted into the piston rod. Therefore, when the holding portion is held by the end portion of the piston rod, the holding portion of the projecting member is connected to the oil seal only by the second connecting portion. Further, in this state, since the second connecting portion is interposed between the holding portion and the inner peripheral portion of the oil seal, the dust lip portion and the vicinity of the second connecting portion in the outer peripheral portion of the piston rod are provided. A gas filling path is formed. Therefore, when the gas is filled in the cylinder, it is possible to fill the gas using this gas filling path. In addition, after the gas is filled, the second connecting portion may be broken by intentionally applying a second predetermined load larger than the first predetermined load to the second connecting portion.
As a result, the holding part is completely separated and removed from the oil seal. As a result, the dust lip portion and the main lip portion of the oil seal are pressed against the outer peripheral surface of the piston rod by the urging force.

As described above, according to the present invention, the gas charging path forming means is constituted by the holding member and the projecting member including the first connecting portion and the second connecting portion, and the first connecting portion and the second connecting portion are formed. Since the configuration is such that the gas filling passage can be formed by utilizing the difference in the breaking load set in the connecting portion of the, and the gas filling passage forming means after the gas filling can be removed, the gas is enclosed in the cylinder body. Similar to the invention described in the first aspect, it becomes unnecessary to insert a part of the jig between the dust lip portion and the outer peripheral surface of the piston rod against the biasing force of the dust lip portion at the time of gas filling.

Further, according to the present invention, it is possible to provide the projecting member integrally with the oil seal when the oil seal is molded. Therefore, in the case where the gas sealing path forming means is formed as a separate component from the oil seal. In comparison, the number of parts and the number of assembly steps are reduced.

Further, according to the present invention, in the assembled state of the oil seal, the holding portion is held at the end portion of the piston rod, and the holding portion is connected to the inner peripheral portion of the oil seal via the second connecting portion. The second connecting portion forming the gas charging passage is surely close to the dust lip portion side. That is, the second connecting portion does not come close to the main lip portion side when the gas is filled.

According to the third aspect of the present invention, in the first step, the oil seal having the gas sealing passage forming means is assembled between the upper end side of the cylindrical body and the outer peripheral surface of the piston rod. . Next, in the second step, the gas is sealed in the cylinder through the gas sealing passage formed by the gas sealing passage forming means. Next, in the third step, the gas sealing passage forming means is removed from the oil seal after the gas sealing.

As described above, according to the present invention, the gas seal path is secured by assembling the oil seal provided with the gas seal path forming means at a predetermined portion. It becomes unnecessary to insert a part of the jig between the dust lip portion and the outer peripheral surface of the piston rod against the biasing force of the dust lip portion at the time of sealing.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] The first embodiment will be described below with reference to FIGS. Note that this embodiment corresponds to an embodiment of the present invention described in claims 1 and 3.

As shown in FIG. 1, the shock absorber 10 includes an outer shell 12 arranged outside and formed into a cylindrical shape, and an inner shell (cylinder) 14 formed inside the outer shell 12 and formed into a cylindrical shape. And a piston rod 16 arranged at the axial center of the inner shell 14 so as to be movable along the axial direction.

A lower cap (not shown) is fitted to the lower end of the outer shell 12. Further, at the lower end of the inner shell 14, a base case (not shown) constituting a support portion of the base valve is fitted. Further, the piston is fixed to the tip of the piston rod 16 with a nut, and leaf valves are attached to the upper end and the lower end of the piston, respectively.

The inner shell 1 is formed by the piston described above.
The chamber inside 4 is divided into an upper chamber 18 and a lower chamber, and a chamber between the outer shell 12 and the inner shell 14 is a reservoir chamber 20. The upper chamber 18 and the lower chamber are filled with oil, and the reservoir chamber 20 is filled with oil and nitrogen gas.

At the upper end of the inner shell 14 described above,
The rod guide 22 is fitted. Rod guide 22
Is a large diameter portion 22 whose outer diameter is equal to the inner diameter of the outer shell 12.
A and a small diameter portion 22B protruding from the axial center portion of the large diameter portion 22A and having an outer diameter equal to the inner diameter of the inner shell 14.
The small diameter portion 22B is fitted to the upper end portion of the inner shell 14, and a cylindrical bush 24 is fitted to the axial center portion thereof and is interposed between the small diameter portion 22B and the outer peripheral surface of the piston rod 16.
In addition, a groove 26 is formed at a predetermined portion of the upper end surface of the large diameter portion 22A, the groove 26 having the radial direction as the longitudinal direction.
Further, in the large-diameter portion 22A, there is formed a gas filling passage 28 which is formed along the axis of the rod guide 22 and which connects the groove 26 and the reservoir chamber 20 described above.

The large diameter portion 22A of the rod guide 22 described above.
An oil seal 30 is provided on the upper end surface side of the.
The oil seal 30 is made of a metallic and annular gold ring 32, an oil seal lip 34 that is vulcanized and bonded to the inner peripheral portion of the metal ring 32 and is made of an elastic material, and a cap to be described later that is attached to the oil seal lip 34 in advance. 52, and.

The above-mentioned oil seal 30 has the groove portion 3 formed on the outer peripheral edge of the upper end of the large diameter portion 22A of the rod guide 22.
After the ring-shaped seal ring 38 is fitted into the inner shell 6, the metal ring 32 is brought into contact with the upper end surface of the large diameter portion 22A of the rod guide 22, and the upper end portion of the outer shell 12 is caulked in this state, whereby the outer shell 12 It is attached to the upper end of the. The seal ring 38 may be integrally formed when the oil seal lip 34 is vulcanized and bonded to the metal ring 32.

The oil seal lip 34 described above is also used.
Is a dust lip portion 40 arranged on the upper surface side of the metal ring 32 for preventing dust from mixing into the outer shell 12 and the inner shell 14, and a main lip portion 42 arranged on the lower surface side of the metal ring 32 for preventing oil leakage. , A holding portion 44 which connects the both and is arranged in the hole peripheral portion (inner peripheral portion) of the metal ring 32.
And The main lip portion 42 is housed in a recess 46 formed in the axial center portion of the large diameter portion 22A of the rod guide 22. A ring-shaped spring 48 is attached to the outer peripheral portion of the dust lip portion 40. Therefore, the sealing surface of the dust lip portion 40 is
It is pressed against the outer peripheral surface of the piston rod 16 with a predetermined sealing pressure. Similarly, on the outer peripheral portion of the main lip portion 42,
A ring-shaped spring 50 is attached. Therefore, the sealing surface of the main lip portion 42 is pressed against the outer peripheral surface of the piston rod 16 with a predetermined sealing pressure.

Here, the oil seal lip 34 described above is used.
On the dust lip portion 40 side of the oil seal lip 34
Before being inserted into the piston rod 16, a resin cap 52 is fitted in advance. As shown in an enlarged manner in FIG. 2, the cap 52 includes a cylindrical insertion portion 54 and a ring-plate-shaped flange portion 56 extending radially outward from an upper end portion of the insertion portion 54. It is configured. Among them, the insertion portion 54 is formed in a substantially triangular shape in cross section in which the upper end portion 54A and the lower end portion 54B are thinned (tapered surfaces) and the intermediate portion 54C is thickened. Therefore, when the insertion portion 54 is inserted inside the dust lip portion 40, a wedge effect is obtained at the lower end portion 54B, which facilitates insertion. In addition, a plurality of (in the present embodiment, four gas passages 58) gas passages 58 are formed at a predetermined portion of the inner peripheral surface of the insertion portion 54 along the axis of the insertion portion 54.

Next, the operation and effect of the present embodiment will be described through the explanation of the procedure for assembling the periphery of the oil seal 30.

First, as shown in FIG. 1, with the insertion portion 54 of the cap 52 inserted in advance inside the dust lip portion 40 against the biasing force of the spring 48, the oil seal 30 including the cap 52. Entire piston rod 1
6 is inserted from the upper end to the lower end. Then, ring 3
2 is brought into contact with the upper end surface of the large diameter portion 22A of the rod guide 22, and the seal ring 38 is pressed into the groove portion 36 of the rod guide 22 while being elastically deformed. Next, by caulking the upper end of the outer shell 12, the oil seal 30 is fixed to the upper end of the outer shell 12 together with the rod guide 22. As a result, the oil seal 30
It is assembled between the upper end of the outer shell 12 and the outer peripheral surface of the rod guide 22. When the oil seal 30 is assembled, the insertion portion 54 of the cap 52 is interposed between the dust lip portion 40 of the oil seal lip 34 and the outer peripheral surface of the piston rod 16. The gas flow path 58 is formed as described above (the above corresponds to the first step in claim 3).

Next, the gas sealing jig 60 is mounted on the upper end of the outer shell 12. The gas charging jig 60 is
It has a bottomed cylindrical shape with a gas introduction hole (not shown), and the bottom part is attached to the outer periphery of the upper end of the outer shell 12 via a packing 62. Next, the gas is supplied from the gas sealing jig 60. The supplied gas is sent to the main lip portion 42 side through the gas passage 58 of the cap 52,
The diameter of the main lip portion 42 is expanded against the biasing force of the spring 50 on the main lip portion 42 side. As a result, the gas is supplied from the recess 46 of the large-diameter portion 22A of the rod guide 22 into the reservoir chamber 20 via the groove 26 and the gas sealing passage 28 (the above is the second step of claim 3). Equivalent).

Next, as shown in FIG.
Is extracted and removed from between the dust lip portion 40 and the outer peripheral surface of the piston rod 16. Specifically, the collar portion 56 of the cap 52 may be pinched and the cap 52 may be slid upward along the piston rod 16. In addition,
At this time, since the upper end portion 54A of the insertion portion 54 of the cap 52 has a tapered surface, the cap 52 can be easily separated from the dust lip portion 40 (the above is the third step of the third aspect). Equivalent).

As described above, in the present embodiment, the oil seal 30 is assembled at a predetermined position with the cap 52 provided with the gas flow path 58 serving as a gas charging passage being previously attached to the dust lip portion 40 side of the oil seal 30. Since the cap 52 is attached and the cap 52 is removed from the oil seal 30 after the gas is filled, a part of the gas filling jig is opposed to the urging force of the spring 48 at the time of filling the gas so that the dust lip portion 40 and the piston rod 16 are partially separated. There is no need to insert it between the outer peripheral surface. Therefore, it is possible to prevent the dust lip portion 40 from being damaged.

In this embodiment, the cap 52, which is a separate component from the oil seal lip 34, is mounted in advance on the dust lip portion 40 side. However, instead of this structure, as shown in FIG. Further, an oil seal 66 may be used in which a projection 64 made of wax (for example, wax) that is a heat-melting material is provided in advance on the inner peripheral surface of the upper end portion of the dust lip portion 40. Also with this configuration, when the oil seal 66 is assembled, the protrusion 64 is provided between the dust lip portion 40 and the outer peripheral surface of the piston rod 16.
Are interposed, a gas sealing path is formed. Also,
After the gas is filled, the protrusion 64 can be easily removed from the oil seal 66 by heating and melting it. Further, according to the above configuration, the configuration and the facility can be simplified as compared with the case where the cap 52 is used. It should be noted that if the protrusion 64 is formed by selecting a wax that melts at around 80 ° C., the absorber performance such as a seal will not be adversely affected.

[Second Embodiment] Next, a second embodiment will be described with reference to FIGS. Note that this embodiment also corresponds to an embodiment of the present invention described in claims 1 and 3. Further, the same components as those of the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in these figures, in the present embodiment, the oil seal 70 includes a metal ring 32, an oil seal lip 34 including a dust lip portion 40, a main lip portion 42 and a holding portion 44. A connecting body 72 connected to the inner peripheral surface of the holding portion 44 of the oil seal lip 34
And is constituted by.

The connecting body 72 has a string-like connecting portion 74 whose one end is connected to the inner peripheral surface of the holding portion 44, and a disc-like picking portion integrally formed at the other end of the connecting portion 74. And 76. The connecting body 72 is formed integrally with the oil seal lip 34 when the oil seal lip 34 is molded.

Further, the connecting portion 74 of the connecting body 72 described above.
A notch 78 (see FIG. 7B) for thinning this portion is formed at the base (end on the holding portion 44 side) of the. Therefore, the strength of the portion where the cutout portion 78 is formed is the lowest.

According to the above construction, the oil seal 70 is assembled with the connecting body 72 pulled out from the dust lip portion 40 to the outside of the oil seal lip 34. In the state after the assembly, the connecting portion 74 of the connecting body 72 is interposed between the dust lip portion 40 and the outer peripheral surface of the piston rod 16, so that the dust lip portion 40 resists the urging force of the spring 48. The diameter is expanded. As a result, a gas flow channel 80 (see FIG. 6) is formed between the dust lip portion 40 and the outer peripheral surface of the piston rod 16 (the above corresponds to the first step in claim 3).

Next, similarly to the above-described first embodiment,
A gas sealing jig 60 is attached to the upper end of the outer shell 12 to supply gas. The supplied gas is connected 72
Is sent to the main lip portion 42 side through the gas flow path 80, and the main lip portion 42 is expanded in diameter against the biasing force of the spring 50 on the main lip portion 42 side. This allows
The gas flows from the recess 46 of the large-diameter portion 22A of the rod guide 22 through the groove 26 and the gas sealing passage 28 to the reservoir chamber 20.
Is supplied to the inside (the above corresponds to the second step in claim 3).

Next, the knob 76 of the connecting body 72 is pulled. As a result, the connecting body 72 has the cutout portion 7 with low rigidity.
8 is broken and removed from the oil seal 70. (The above corresponds to the third step of claim 3).

As described above, in this embodiment, the gas flow path 80
The oil seal 70 is preliminarily provided with the connecting body 72 having the connecting portion 74 for forming the knob, and the knob portion 7 is provided after gas filling.
Since 6 is pulled and ruptured from the notch 78 to be removed, as in the first embodiment described above, a part of the gas charging jig is resisted against the biasing force of the spring 48 at the time of gas charging. It is not necessary to insert it between the strip portion 40 and the outer peripheral surface of the piston rod 16. Therefore, it is possible to prevent the dust lip portion 40 from being damaged.

Further, in this embodiment, the connecting body 72 is used to form the oil seal lip 34 when the oil seal lip 34 is molded.
Since it can be integrally formed with the oil seal lip 34, the number of parts and the number of assembling steps can be reduced as compared with the first embodiment in which the cap 52 is formed separately from the oil seal lip 34. Therefore, cost reduction can be achieved.

[Third Embodiment] Next, a third embodiment will be described with reference to FIGS. 8 and 9. Note that this embodiment corresponds to an embodiment of the present invention described in claims 1 to 3. Further, the same components as those of the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in these drawings, in the present embodiment, the oil seal 90 includes a metal ring 32 and an oil seal lip 34 including a dust lip portion 40, a main lip portion 42 and a holding portion 44. , A projecting member 92 projectingly arranged on the axial center side of the oil seal lip 34.

As shown in FIG. 9, the protruding member 92 is
An annular holding portion 94, and a pair of first connecting portions 96 extending radially outward from a predetermined position in the circumferential direction of the holding portion 94 to connect the holding portion 94 and the holding portion 44 of the oil seal lip 34. Similarly, the holding portion 94 and the oil seal lip 3
And a second connecting portion 98 that connects the four holding portions 44. The protruding member 92 is formed integrally with the oil seal lip 34 when the oil seal lip 34 is molded.

Of these, the inner diameter dimension D ₁ of the holding portion 94 is
It is set to be larger than the outer diameter dimension D ₂ of the small diameter portion (male thread portion) 16A of the piston rod 16 inserted into the holding portion 94, but slightly smaller than the outer diameter dimension D ₃ of the large diameter portion 16B. Has been done.

Further, first thin-walled portions 100 are formed at the roots of the pair of first connecting portions 96 (the connecting portions of the oil seal lip 34 with the holding portion 44). Similarly, at the base of the second connecting portion 98, the second thin portion 10
2 are formed. Further, at the predetermined position in the circumferential direction of the holding portion 94 (the intermediate position between the pair of first connecting portions 96), the third
The thin portion 104 is formed. The cross-sectional area is set larger in the order of the first thin wall portion 100, the third thin wall portion 104, and the second thin wall portion 102. Therefore, the first thin wall portion 100, the third thin wall portion 104, and the second thin wall portion 102.
The fracture strength increases in the order of.

According to the above construction, when the oil seal 90 is assembled, the small diameter portion 16A of the piston rod 16 is first inserted into the holding portion 94 of the protruding member 92. At this time, the inner diameter dimension D ₁ of the holding portion 94> the small diameter portion 16A
Since the outer diameter dimension is D ₂ , the breaking load does not act on the first thin portion 100 to the third thin portion 104. Next, the holding portion 94 is inserted into the large diameter portion 16B of the piston rod 16. In this case, the inner diameter dimension D ₁ of the holding portion 94 <large diameter portion 1
Since 6B is an outer diameter D ₃ of the holding portion 94 while elastically deformed in a direction to increase in diameter, tensile load on the first thin portion 100 to the third thin portion 104 acts respectively. Therefore, the first thin portion 100 having the lowest breaking strength is broken first, and the first connecting portion 96 is separated from the oil seal lip 34. The breaking load acting on the first thin portion 100 at this time corresponds to the first predetermined load according to claim 2.

Subsequently, in the process of inserting the holding portion 94 into the large diameter portion 16B, the tensile load continues to act on the third thin portion 104, so that the third thin portion 104 breaks.
As a result, the holding portion 94 is divided. However, since the breaking strength of the second thin wall portion 102 is high, even if the holding portion 94 is assembled at a predetermined position of the large diameter portion 16B of the piston rod 16, the second thin wall portion 102 does not break yet. Therefore, the holding portion 94 is in the assembled state in a state of being connected to the oil seal lip 34 by the second connecting portion 98. In the state after the assembling, the second connecting portion 98 is interposed between the dust lip portion 40 and the outer peripheral surface of the large diameter portion 16B of the piston rod 16, so that the vicinity of the second connecting portion 98 is described above. A gas flow channel (not shown) similar to that of the second embodiment is formed (the above corresponds to the first step of claim 3).

Next, the gas is supplied in the same manner as in the first and second embodiments described above. The supplied gas is finally supplied into the reservoir chamber 20 through the gas flow path formed by the second connecting portion 98 (above,
(Corresponding to the second step of claim 3).

Next, the second connecting portion 98 is intentionally pulled. The breaking load that acts on the second thin portion 102 at this time corresponds to the second predetermined load. As a result, the second connecting portion 98 has the second thin portion 1
It is broken from 02 and removed from the oil seal 90.
(The above corresponds to the third step of claim 3).

As described above, in the present embodiment, the projecting member composed of the annular holding portion 94 and the first connecting portion 96 and the second connecting portion 98 connecting the holding portion 94 and the oil seal lip 34. 92 is provided on the oil seal lip 34, and the first thin wall portion 100 and the third thin wall portion 104 are fractured in this order to form a gas flow path near the second connecting portion 98, and after the gas is filled, the second flow path is formed. Since the thin member 102 is broken to remove the protruding member 92,
In the same manner as in the above embodiment, a part of the gas charging jig is opposed to the biasing force of the spring 48 at the time of gas charging and the dust lip portion 40
It becomes unnecessary to insert it between the piston rod 16 and the outer peripheral surface of the piston rod 16. Therefore, it is possible to prevent the dust lip portion 40 from being damaged.

Also in this embodiment, the protruding member 9
Since 2 can be integrally formed with the oil seal lip 34 when the oil seal lip 34 is molded, it is possible to reduce the number of parts and the number of assembling steps as in the second embodiment. Therefore, cost reduction can be achieved.

Further, according to this embodiment, the assembled state of the oil seal 90, that is, the holding portion 94 is the piston rod 1.
In the state of being held by the large-diameter portion 16B of No. 6, the second connecting portion 98 is always close to the dust lip portion 40 side. That is, in the above-described second embodiment, it is considered that the connecting body 72 hangs down to the main lip portion 42 side before assembly,
When the oil seal 70 is assembled in this state, the connecting body 7
Although the second connecting portion 74 approaches the main lip portion 42 side, according to the present embodiment, the second connecting portion 9 is filled at the time of gas filling.
8 does not come close to the main lip portion 42 side. Therefore, the reliability of the gas charging work can be ensured.

[0058]

As described above, the oil seal structure of the hydraulic shock absorber according to the present invention as set forth in claim 1 is provided in the oil seal, and when the oil seal is assembled, the cylindrical body of the main lip portion is provided. Since a gas injection path is formed between the dust lip portion arranged on the external side and the outer peripheral surface of the piston rod, and a means for forming a gas injection path that can be removed from the oil seal after gas injection is provided, so when gas is injected It is no longer necessary to insert a part of the jig between the dust lip portion and the outer peripheral surface of the piston rod against the urging force of the dust lip portion, so that gas is sealed without damaging the dust lip portion. It has an excellent effect of being able to.

According to a second aspect of the present invention, there is provided an oil seal structure for a hydraulic shock absorber according to the first aspect of the present invention.
An annular holding part that is inserted into the piston rod and held at the end of the piston rod, and is integrally extended from this holding part and is connected to the inner peripheral part of the oil seal, and is connected to the piston rod of the holding part. A first connecting portion that breaks due to a first predetermined load that acts at the time of insertion of the oil, and a second connecting member that is integrally extended from the holding portion and that is connected to the inner peripheral portion of the oil seal and that is larger than the first predetermined load. The gas sealing path forming means is constituted by the projecting member configured to include the second connecting portion that is broken when a predetermined load is applied, and thus the dust lip portion is damaged as in the invention according to claim 1. It has an excellent effect that the gas can be enclosed without giving the gas.

Further, according to the present invention, since it is possible to provide the projecting member integrally with the oil seal at the time of molding the oil seal, it is possible to reduce the number of parts and the number of assembling steps, thereby reducing the cost. The effect of being able to achieve

Further, according to the present invention, in the assembled state of the oil seal, the gas filling passage is formed when the gas is filled.
Since the connecting portion of is reliably close to the dust lip portion side and is not close to the main lip portion side, the effect of ensuring the reliability of the gas charging operation can be obtained.

According to the third aspect of the present invention, there is provided a method for filling gas in a hydraulic shock absorber according to the present invention, in which an oil seal having a gas filling passage forming means is arranged so as to be movable in the axial direction in the upper end side of the cylinder. And a second step of assembling the gas into the cylinder from the gas sealing passage formed by the gas sealing passage forming means, and a gas sealing after the gas sealing. And a third step of removing the path forming means from the oil seal.
Alternatively, as in the second aspect of the invention, it has an excellent effect that the gas can be enclosed without damaging the dust lip portion.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an oil seal structure of a shock absorber according to a first embodiment.

FIG. 2 is an enlarged cross-sectional view showing the cap shown in FIG.

FIG. 3 is a vertical cross-sectional view corresponding to FIG. 1, showing a state in which the cap is removed after the gas is filled.

FIG. 4 is a vertical cross-sectional view of an oil seal showing an embodiment using a protrusion formed of wax instead of a cap.

FIG. 5 is a longitudinal sectional view showing an oil seal structure of a shock absorber according to a second embodiment.

FIG. 6 is a plan view of the oil seal structure shown in FIG.

FIG. 7A is a vertical cross-sectional view showing an oil seal provided with a connecting body, and FIG. 7B is an enlarged view of FIG.

FIG. 8 is a vertical cross-sectional view showing an oil seal structure of a shock absorber according to a third embodiment.

9 is a plan view showing a protruding member shown in FIG. 8. FIG.

FIG. 10 is a vertical cross-sectional view showing an oil seal structure of a shock absorber according to a conventional example.

[Explanation of symbols]

 10 shock absorber (hydraulic shock absorber) 12 outer shell (cylindrical body) 16 piston rod 30 oil seal 40 dust lip part 42 main lip part 48 spring 50 spring 52 cap (gas injection path forming means) 58 gas flow path (gas injection path) 64 Protrusions (Gas Filling Route Forming Means) 66 Oil Seal 70 Oil Seal 72 Coupling Body (Gas Filling Route Forming Means) 80 Gas Flow Path (Gas Filling Route) 90 Oil Seal 92 Protruding Member (Gas Filling Route Forming Means) 94 Holding Part 96 First connection part 98 Second connection part

Front Page Continuation (72) Inventor Ichiro Okada 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd.

Claims (3)

[Claims] 1. A cylinder body is assembled between an upper end side thereof and an outer peripheral surface of a piston rod which is arranged so as to be movable in the cylinder body in an axial direction. An oil seal structure of a hydraulic shock absorber including an oil seal including a dust lip portion and a main lip portion that are pressed against each other by an urging force, which is provided on the oil seal, and the main lip portion when the oil seal is assembled. A gas sealing passage is formed between the dust lip portion arranged on the outer side of the cylindrical body and the outer peripheral surface of the piston rod, and has a gas sealing passage forming means that can be removed from the oil seal after gas sealing. The oil seal structure of the hydraulic shock absorber. 2. An annular holding portion which is inserted into the piston rod and is held at an end portion of the piston rod, and which integrally extends from the holding portion and is connected to an inner peripheral portion of the oil seal, A first connecting portion that breaks due to a first predetermined load that acts when the holding portion is inserted into the piston rod; and a first connecting portion that extends integrally from the holding portion and is connected to an inner peripheral portion of the oil seal, A second connecting portion that breaks when a second predetermined load, which is larger than the first predetermined load, acts on the gas injection path forming means. The oil seal structure for a hydraulic shock absorber according to claim 1. 3. A hydraulic shock absorber provided with the oil seal according to claim 1 or 2, wherein an oil seal provided with the gas sealing path forming means is provided between the upper end side of the cylinder and the cylinder. A first step of assembling with the outer peripheral surface of the piston rod arranged so as to be movable in the axial direction, and a second step of sealing gas into the cylinder from the gas sealing passage formed by the gas sealing passage forming means. And a third step of removing the gas injection path forming means from the oil seal after the gas injection, the gas injection method of the hydraulic shock absorber, comprising: