JP2005023966A - Cylinder device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder device capable of enhancing sealability, enabling sub-assembly and enhancing assemblability in a seal element of a piston rod of a hydraulic damper. <P>SOLUTION: A space between a cylinder 2 and a piston rod 9 is sealed by a seal element 4. The seal element 4 comprises three members including a dust lip 19, a dust seal 15 in which an inner seal lip 20 and a thin-walled part 21 are vulcanization-bonded to a reinforcing member 18, a main seal 16 in which a main lip 26 is vulcanization-bonded to a reinforcing member 24, and a backup ring 17. These members can be sub-assembled by fitting the backup ring 17 to the main lip 26, and inserting the reinforcing member 24 in an inner circumferential groove 25 of the inner seal lip 20. The seal element 4 can be easily and reliably fixed to the cylinder 2 by caulking a tip part of a side wall of the cylinder 2, and abutting a caulked part 30 on the reinforcing member 18. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
[Industrial application fields]
The present invention relates to a cylinder device such as a hydraulic shock absorber in which a sealing element is provided between a cylinder enclosing a fluid and a rod extending from the cylinder to the outside.
[0002]
[Prior art]
For example, in a cylindrical hydraulic shock absorber used for an automobile suspension device, generally, a sealing element is attached to an end portion of a cylinder in which oil is sealed and a piston rod protrudes from the piston rod. Is slidably sealed. This sealing element is required to ensure smooth sliding of the piston rod, prevent leakage of oil under high pressure and intrusion of foreign matter such as dust and rainwater, and have sufficient durability. The
[0003]
As a prior art related to this type of sealing element, for example, Patent Document 1 discloses a first sealing member for preventing leakage of oil, a second sealing member for preventing foreign matter from entering, and a first under high pressure. The seal element comprising three members of the backup ring for preventing the deformation of the sealing member of this, and among these three members, the backup ring is integrated with the second sealing member to reduce the size and improve the assembly workability. A sealing element is described.
[Patent Document 1]
Japanese Patent Laid-Open No. 10-205625 [0004]
[Problems to be solved by the invention]
As described above, the sealing element of the hydraulic shock absorber includes a hydraulic shock absorber as well as ensuring smooth sliding of the piston rod, preventing leakage of oil under high pressure, preventing foreign matter from entering, and ensuring sufficient durability. In this manufacturing process, it is required to be easily assembled, and further improvement is desired in order to satisfy this requirement at a higher level.
[0005]
This invention is made | formed in view of said point, and it aims at providing the cylinder apparatus provided with the sealing element excellent in the sealing performance and the assembly | attachment property.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the invention of claim 1 is a cylinder device in which a seal element is provided between a cylinder and a rod extending from the inside of the cylinder to the outside, wherein the seal element includes:
A dust seal disposed facing the outside of the cylinder and having a dust lip adhered to the rod fixed to an inner peripheral portion of an annular first reinforcing member fitted into the cylinder;
A main seal disposed facing the inside of the cylinder and having a main lip adhered to the rod fixed to an inner peripheral portion of an annular second reinforcing member inserted into the cylinder;
A backup ring that is disposed between the dust seal and the main seal, is fitted to the main lip, and supports the main lip against the internal pressure of the cylinder;
An inner surface seal lip that is fixed to the outer periphery of the first reinforcing member or the second reinforcing member and is in close contact with the inner surface of the cylinder;
A sealing layer fixed to a surface of the first reinforcing member facing the second reinforcing member or a surface of the second reinforcing member facing the first reinforcing member;
An engaging lip fixed to the first reinforcing member and capable of fitting the second reinforcing member, or fixed to the second reinforcing member and capable of fitting the first reinforcing member. To do.
By being configured in this way, the backup ring is fitted to the main lip, and the first or second reinforcing member is fitted into the engaging lip, so that the first and second reinforcing members are sealed by the seal layer, The dust seal, main seal and backup ring can be sub-assembled together.
A cylinder device according to a second aspect of the invention is characterized in that, in the configuration of the first aspect, inner peripheral portions of the first reinforcing member and the second reinforcing member are covered with a rubber layer.
With this configuration, the surface of the rod is not damaged by the first and second reinforcing members when the seal element is assembled.
According to a third aspect of the present invention, there is provided the cylinder device according to the first or second aspect, wherein the seal element is fixed by crimping a tip end portion of the cylinder into contact with the first reinforcing member. It is characterized by that.
With this configuration, the caulking portion at the tip of the cylinder directly contacts the first reinforcing member, so that the sealing element can be easily and reliably caulked and fixed.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
A first embodiment of the present invention will be described with reference to FIGS. 1 to 3 and FIG.
As shown in FIG. 7, the hydraulic shock absorber 1 (cylinder device) according to the present embodiment is a single cylinder type hydraulic shock absorber, and includes a rod guide 3 and an oil seal 4 at the opening of a bottomed cylindrical cylinder 2. A (seal element) is attached, and a free piston 5 is slidably fitted on the bottom side in the cylinder 2. The cylinder 2 is defined by a free piston 5 into a gas chamber 6 on the bottom side and an oil chamber 7 on the other end side. The gas chamber 6 is filled with high-pressure gas, and the oil chamber 7 is filled with oil liquid. It is enclosed.
[0008]
A piston 8 is slidably fitted in the oil chamber 7 of the cylinder 2, and the oil chamber 7 is defined by the piston 8 as two chambers, a cylinder upper chamber 7 </ b> A and a cylinder lower chamber 7 </ b> B. One end of a piston rod 9 is connected to the piston 8 by a nut 10, and the other end side of the piston rod 9 is slidably and liquid-tightly inserted into the rod guide 3 and the oil seal 4 to the outside. It has been extended.
[0009]
The piston 8 is provided with an extension side oil passage 11 and a contraction side oil passage 12 that communicate between the cylinder upper and lower chambers 7A and 7B. The extension-side oil passage 11 and the contraction-side oil passage 12 are respectively provided with an extension-side damping force generation mechanism 13 and a compression-side damping force generation composed of an orifice, a disk valve, and the like that control the flow of the oil to generate a damping force. A mechanism 14 is provided.
[0010]
With this configuration, during the extension stroke of the piston rod 9, as the piston 8 in the cylinder 2 slides, the oil in the cylinder upper chamber 7A flows to the cylinder lower chamber 7B through the extension-side oil passage 11 of the piston 8, A damping force is generated by the extension side damping force generation mechanism 13. Further, during the contraction stroke, the oil in the cylinder lower chamber 7 </ b> B flows through the contraction side oil passage 13 to the cylinder upper chamber 7 </ b> A, and the contraction side damping force generation mechanism 14 generates a damping force. At this time, the volume change of the oil chamber 7 due to the entry and exit of the piston rod 9 is compensated by the free piston 5 moving and compressing and expanding the high-pressure gas in the gas chamber 6.
[0011]
Next, the oil seal 4 which is a main part of the present embodiment will be described with reference to FIGS. 1 to 3.
As shown in FIG. 1, the oil seal 4 includes a dust seal 15 disposed facing the outside of the cylinder 2, a main seal 16 disposed facing the inside, and a backup ring 17 disposed therebetween. And three members.
[0012]
The dust seal 15 is made of a ring-shaped reinforcing member 18 (first reinforcing member) made of a rigid material such as metal, a rubber dust lip 19, an inner surface seal lip 20, and a thin portion 21 (seal layer) that integrally couples these. Vulcanized and bonded. The reinforcing member 18 has an outer diameter that fits to the inner peripheral surface of the cylinder 2 and an inner diameter that is slightly larger than the outer diameter of the piston rod 9. The dust lip 19 is provided on the inner peripheral portion of the outer end surface of the reinforcing member 18, and the tip end portion thereof is slidably adhered to the outer peripheral surface of the piston rod 9 to prevent entry of foreign matters such as dust and rainwater. An annular spring 23 is attached to the outer periphery of the dust lip 19 in order to improve the adhesion with the piston rod 9. The inner surface seal lip 20 is provided on the outer peripheral portion of the inner end surface of the reinforcing member 18 and is in close contact with the inner peripheral surface of the cylinder 2 to prevent leakage of oil in the cylinder 2. The inner surface seal lip 20 is formed with an inner peripheral groove 25 (engagement lip) for fitting an outer peripheral portion of a reinforcing member 24 (described later) of the main seal 16. The thin-walled portion 21 (rubber layer) covers the inner end surface and the inner peripheral surface of the reinforcing member 18, and is vulcanized and bonded to the reinforcing member 18 integrally with the dust lip 19 and the inner surface seal lip 20.
[0013]
The main seal 16 is obtained by vulcanizing and bonding a rubber main lip 26 to a ring-shaped reinforcing member 24 (second reinforcing member) made of a rigid material such as metal. The reinforcing member 24 has an outer diameter smaller than the outer diameter of the reinforcing member 18 of the dust seal 15, an inner diameter larger than the outer diameter of the backup ring 17, and its outer peripheral portion is fitted in the inner peripheral groove 25 of the inner surface seal lip 20 of the main seal 15. In combination, the one end surface is in close contact with the thin portion 21. The main lip 26 is provided on the inner peripheral portion of the inner end surface of the reinforcing member 24, and the tip end portion is slidably in close contact with the outer peripheral surface of the piston rod 9, thereby preventing leakage of oil in the cylinder 2. An annular spring 27 is attached to the outer peripheral portion of the main lip 26 in order to improve the adhesion with the piston rod 9. The main lip 26 (rubber layer) is vulcanized and bonded so as to cover the inner end surface and inner peripheral surface of the reinforcing member 24, and the stepped outer peripheral portion of the backup ring 17 is provided on the inner peripheral side of the reinforcing member 24. A stepped fitting portion 28 for fitting the two is formed.
[0014]
The backup ring 17 is a ring-shaped member made of fluorine resin or the like having moderate rigidity, low friction and wear resistance, and a stepped portion that is fitted to the fitting portion 28 of the main lip of the main seal 16 on the outer peripheral portion. 29 is formed, the inner peripheral portion is in sliding contact with and guides the outer peripheral surface of the piston rod 9, and one end surface is in close contact with the thin wall portion 21 of the dust seal 15. The seal 26 is supported.
[0015]
In the oil seal 4, the stepped portion 29 of the backup ring 17 is fitted to the fitting portion 28 of the main lip 26 of the main seal 16, and the outer peripheral portion of the reinforcing member 16 of the main seal 16 is connected to the inner seal lip 20 of the dust seal 15. By fitting in the circumferential groove 25, the dust seal 15, the main seal 16, and the backup ring 16 can be integrally sub-assembled.
[0016]
Next, the structure of the attachment part of the oil seal 4 to the cylinder 2 will be described.
The rod guide 3 is fitted in the cylinder 2 and is fixed by caulking around the cylinder 2. The oil seal 4 is fitted in the cylinder 2, the end surface of the reinforcing member 24 of the main seal 16 abuts on the tip of the annular convex portion 3 </ b> A formed at one end of the rod guide, and the tip of the side wall of the cylinder 2. Is fixed by causing the crimping portion 30 to contact the reinforcing member 18 of the dust seal 15.
[0017]
Between the rod guide 3 and the oil seal 4, an oil chamber 31 is formed by the annular convex portion 3 </ b> A of the rod guide 3, and the oil chamber 31 is a cylinder through a throttle passage 32 formed in the rod guide 3. It communicates with the upper chamber 7.
[0018]
Next, the operation of the present embodiment configured as described above will be described.
The oil seal 4 is sealed between the piston rod 9 by the dust lip 19 in a state where it is attached to the cylinder 2 to prevent foreign matter such as dust and rainwater from entering, and the piston lip 9 by the main lip 26. Between the inner surface of the cylinder 2 by the inner seal lip 20 and between the reinforcing member 18 of the dust seal and the reinforcing member 24 of the main seal 16 by the thin wall portion 21. Prevent leakage of oil inside. At this time, the main lip 26 is supported by the backup ring 17 against the internal pressure of the cylinder 2 to prevent the deformation thereof. Further, by applying an appropriate sliding resistance to the piston rod 9 by the backup ring 17, the vibration of the minute stroke of the piston rod 9 is attenuated and a stable damping force is generated. In addition, the sealing performance of the oil seal 4 is enhanced by gradually reducing the pressure of the oil acting on the oil chamber 31 by the throttle passage 32 of the rod guide.
[0019]
The oil seal 4 can be sub-assembled with the dust seal 15, the main seal 16, and the backup ring 17, and can be assembled to the cylinder 2 by inserting the piston rod 9 in an integrated state. ing. At this time, the dust seal 15 and the main seal 16 are integrated by fitting the inner peripheral groove 25 of the rubber inner seal lip 20 and the reinforcing member 24 made of a rigid material such as metal. Is obtained, and the fitting state can be easily confirmed. Further, since the reinforcing members 18 and 24 such as metal of the dust seal 15 and the main seal 16 are covered with the thin rubber portion 21 and the main lip 26 and are not exposed to the piston rod 9 side, the piston rod 9 is attached at the time of assembly. It will not hurt.
[0020]
The oil seal 4 fitted in the cylinder 2 is fixed by caulking the front end of the side wall of the cylinder 2 and bringing the caulking portion 30 into contact with the reinforcing member 18 such as metal, so that the reinforcing member 18 is used as a fulcrum. The caulking portion 30 can be bent, and the caulking can be fixed easily and reliably.
[0021]
Next, a second embodiment of the present invention will be described with reference to FIGS. The hydraulic shock absorber according to the second embodiment has the same structure as that of the first embodiment except that the structure of the oil seal is different. Only different parts will be described in detail.
[0022]
As shown in FIGS. 4 to 6, in the hydraulic shock absorber 1 according to the second embodiment, the oil seal 33 includes three members, that is, a dust seal 34, a main seal 35, and a backup ring 17.
[0023]
In the dust seal 34, the inner seal lip 20 is omitted from the dust seal 15 of the first embodiment, and the thin portion 21 is not provided on the inner end surface of the reinforcing member 36. Further, an engagement step portion 37 is formed at an edge portion on the inner end face side of the outer peripheral portion of the reinforcing member 36.
[0024]
On the other hand, the main seal 35 has an outer diameter with which the reinforcing member 38 is fitted to the inner peripheral surface of the cylinder 2, and an engagement step portion of the dust seal 34 on the outer peripheral portion of the outer end surface (end surface on the dust seal 34 side). A rubber engaging lip 39 which is concavo-convexly fitted to 37 is vulcanized and bonded. Further, a thin rubber portion 40 (seal layer) that integrally connects the engaging lip 39 and the main lip 26 is vulcanized and bonded so as to cover the outer end face of the reinforcing member 38. A rubber inner surface seal lip 41 that adheres to the inner peripheral surface of the cylinder 2 and prevents leakage of oil in the cylinder 2 is added to the outer peripheral portion of the inner end surface (end surface on the cylinder chamber 7A side) of the reinforcing member 38. Sulfur bonded. A thin rubber portion 42 that integrally couples the inner seal lip 40 and the main lip 26 is vulcanized and bonded so as to cover the inner end surface of the reinforcing member 38.
[0025]
With this configuration, the oil seal 33 is configured to fit the stepped portion 29 of the backup ring 17 to the fitting portion 28 of the main lip 26 of the main seal 16 in the same manner as in the first embodiment. By fitting the engagement lip 39 of the 35 to the engagement step portion 37 of the dust seal, the dust seal 34, the main seal 35, and the backup ring 16 can be integrally assembled. Then, it can be fixed by fitting into the cylinder 2, caulking the tip of the side wall of the cylinder 2 inward, and bringing the caulking portion 30 into contact with the reinforcing member 36 of the dust seal 34.
[0026]
The oil seal 33 is attached to the cylinder 2 and sealed between the piston rod 9 by the dust lip 19 and sealed between the piston rod 9 by the main lip 26, and the inner seal lip of the main seal 35. 41 is sealed between the inner surface of the cylinder 2 and the thin portion 40 is sealed between the reinforcing member 36 of the dust seal 34. Thereby, the effect | action and effect similar to the thing of the said 1st Embodiment can be show | played.
[0027]
In the first and second embodiments, the case where the present invention is applied to a single cylinder type hydraulic shock absorber is described as an example. However, the present invention is not limited to this, and the present invention is not limited to this. In addition to the hydraulic shock absorber, it can be applied to other cylinder devices as long as the rod extends from the cylinder filled with fluid to the outside. .
[0028]
【The invention's effect】
As described in detail above, according to the cylinder device according to the invention of claim 1, the seal element can be easily assembled to the cylinder by sub-assembling the three members of the dust seal, the main seal, and the backup ring, It is possible to securely seal between the cylinder and the rod.
According to the cylinder device of the second aspect of the present invention, since the inner peripheral portions of the first and second reinforcing members are covered with the rubber layer, the rods are inserted by the first and second reinforcing members when the sealing element is assembled. Will not hurt the surface.
According to the cylinder device of the third aspect of the present invention, the sealing element can be easily and surely fixed by caulking the tip of the cylinder and bringing it into contact with the first reinforcing member.
[Brief description of the drawings]
FIG. 1 is an enlarged longitudinal sectional view showing a mounting portion of a sealing element which is a main part of a hydraulic shock absorber according to a first embodiment of the present invention.
FIG. 2 is a longitudinal sectional view showing a state in which the sealing element shown in FIG. 1 is sub-assembled.
FIG. 3 is an exploded longitudinal sectional view of the sealing element shown in FIG.
FIG. 4 is an enlarged longitudinal sectional view showing a mounting portion of a sealing element, which is a main part of a hydraulic shock absorber according to a second embodiment of the present invention.
5 is a longitudinal sectional view showing a state in which the sealing element shown in FIG. 4 is sub-assembled.
6 is an exploded longitudinal sectional view of the sealing element shown in FIG. 4. FIG.
FIG. 7 is a longitudinal sectional view of a hydraulic shock absorber according to one embodiment of the present invention.
[Explanation of symbols]
1 Hydraulic shock absorber (cylinder device)
4 Seal element 9 Piston rod (rod)
15 Dust seal 16 Main seal 17 Backup ring 18 Reinforcing member (first reinforcing member)
19 Dustrip 20 Internal seal lip 21 Thin part (seal layer, rubber layer)
24 Reinforcing member (second reinforcing member)
25 Inner circumferential groove (engagement lip)
26 Main lip (rubber layer)

Claims (3)

A cylinder device in which a sealing element is provided between a cylinder and a rod extending from the inside of the cylinder to the outside, wherein the sealing element includes:
A dust seal disposed facing the outside of the cylinder and having a dust lip adhering to the rod adhered to an inner peripheral portion of an annular first reinforcing member fitted into the cylinder;
A main seal disposed facing the inside of the cylinder and having a main lip adhered to the rod fixed to an inner peripheral portion of an annular second reinforcing member inserted into the cylinder;
A backup ring that is disposed between the dust seal and the main seal, is fitted to the main lip, and supports the main lip against the internal pressure of the cylinder;
An inner surface seal lip fixed to the outer periphery of the first reinforcing member or the second reinforcing member and closely contacting the inner surface of the cylinder;
A sealing layer fixed to a surface of the first reinforcing member facing the second reinforcing member or a surface of the second reinforcing member facing the first reinforcing member;
An engaging lip fixed to the first reinforcing member and capable of fitting the second reinforcing member or fixed to the second reinforcing member and capable of fitting the first reinforcing member. Cylinder device to do. 2. The cylinder device according to claim 1, wherein inner peripheral portions of the first reinforcing member and the second reinforcing member are covered with a rubber layer. 3. The cylinder device according to claim 1, wherein the sealing element is fixed by caulking a tip portion of the cylinder and bringing it into contact with the first reinforcing member. 4.

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