JPH11218178A - Rod seal structure for hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a defect caused by the separation of a rod seal from a holding plate only by making simple improvement in a hydraulic shock absorber without heightening outer shell fastening force unnecessarily. SOLUTION: A holding plate 10 provided with a rod seal 7 on the inner peripheral side is placed directly or indirectly on the end part of a cylinder 3, and an outer shell 2 is fastened to hold the rod seal 7 by the holding plate 10 while applying fastening force directly to the cylinder 3 through the holding plate 10. In such rod seal structure for a hydraulic shock absorber, a thin collar- like extension part 19 is formed on the inner peripheral side of the holding plate 10, and a holding part 18 of the rod seal 7 is inserted and fastened into this extension part 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic shock absorber used for a suspension device for a vehicle such as an automobile which elastically supports a vehicle body with respect to wheels, and more particularly, to a hydraulic shock absorber.
The present invention relates to an improvement in a rod seal structure of the hydraulic shock absorber.

[0002]

2. Description of the Related Art Conventionally, as a rod seal structure in a hydraulic shock absorber of this type, as shown in FIG. 8, for example, as shown in FIG. 7 to the holding part 18 integrally
The bonding strength is increased by bonding and covering the holding portion 18 over the entire upper surface of the holding plate 10.

Then, the holding plate 10 provided with the rod seal 7 is directly or indirectly mounted on the end of the cylinder 3 (the latter in FIG. 8). Holder 1 of rod seal 7 between
There is known one that is sealed at 8.

However, in this case, when the outer shell 2 is crimped, the holding portion 18 of the rod seal 7 is crushed and the pressing force against the cylinder 3 is secured, so that a relatively large crimping force is required. .

[0005] To this end, the hydraulic shock absorber 1 is formed by crimping force.
Deformation or breakage of the internal components in, or
Not only does the holding portion 18 of the rod seal 7 break, causing peeling from the holding plate 10, but also causing the inconvenience that the pressing force against the cylinder 3 is reduced due to the extension of the holding portion 18.

[0006]

Therefore, as shown in FIG. 9, the holding portion 18 of the rod seal 7 is shortened inward, and a seal 12 is formed on the outer periphery of the holding plate 10 on the front side.
An improved structure proposal has been proposed in which a caulking force is directly applied to the holding plate 10 while sealing the caulked portion of the outer shell 2 with the seal 12.

According to this structure, since the crimping force when caulking the outer shell 2 can be directly transmitted to the holding plate 10, the holding portion 1 of the rod seal 7 described above can be used.
Various inconveniences of the structure in which the entire upper surface of the zero is covered can be eliminated.

Nevertheless, with the improved structure described above, the contact area between the holding portion 18 and the holding plate 10 in the rod seal 7 is reduced, and the outer edge of the holding portion 18 is And sticks out on the surface of the rod seal 7, thereby causing a disadvantage that the rod seal 7 may be damaged by peeling.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a hydraulic shock absorber which can prevent a loss due to peeling of a rod seal from a holding plate by making a simple improvement without unnecessarily increasing a caulking force of an outer shell. Is to provide a rod seal structure.

[0010]

In order to achieve the above object, according to the present invention, a holding plate provided with a rod seal on the inner peripheral side is directly or indirectly mounted on an end of a cylinder to form an outer shell. In the rod seal structure of the hydraulic shock absorber in which the rod seal is held by the holding plate while directly applying a tightening force to the cylinder through the holding plate, a thin flange is provided on the inner peripheral side of the holding plate. An extended portion was formed, and the holding portion of the rod seal was inserted into the extended portion and fixed.

As a result, the caulking force of the outer shell is directly applied to the holding plate of the rod seal, so that the caulking force causes deformation or breakage of components inside the hydraulic shock absorber, or the caulking portion may be damaged. It is possible to prevent the pressing force against the cylinder from being reduced due to the extension of the intervening member.

In addition, the holding portion of the rod seal covers the extension of the holding plate and is embedded on the same surface or in a state close to the same surface. Can also be prevented.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a hydraulic shock absorber according to a first embodiment of the present invention; Only the rod seal portion will be illustrated and described.

As shown in FIG. 1, the hydraulic shock absorber 1 has a multi-cylinder main body portion 4 including a cylinder 3 arranged concentrically at a predetermined interval inside an outer shell 2. The reservoir chamber R is formed between the outer shell 2 and the cylinder 3.

A piston (not shown) provided with an extension-side damping valve and a compression-side suction valve is slidably fitted inside the cylinder 3. Further, between the bottom of the cylinder 3 and the reservoir chamber R, A base valve (not shown) having a compression damping valve and an extension suction valve is also provided.

A piston rod 5 integrally extends upward from the piston.
Penetrates the oil chamber A on the rod side above the cylinder 3 defined by the piston, and the main body 4 of the hydraulic shock absorber 1
Extending outward from the top.

A rod guide 6 for guiding a piston rod 5 from the outer shell 2 to the cylinder 3 is provided inside the upper end of the main body 4 of the hydraulic shock absorber 1, and a piston rod 5 extending upward from the main body 4. Rod seals 7 are provided to seal the protruding portions of each of them tightly.

The rod guide 6 is formed as a pressed product by folding the upper and lower ends of the cylindrical member outwardly and inwardly into a U-shape with a press machine, and forming reinforcing ribs 8 together.

The rod guide 6 is fitted to the upper end of the cylinder 3 so as to extend into the outer shell 2, and the piston rod 5 is slidably guided by a bearing 9 mounted on the inner peripheral surface. Positioned in place.

On the other hand, the rod seal 7 is integrally attached to an inner peripheral portion of a perforated disk-shaped holding plate 10. The holding plate 10 is fitted from the upper end of the outer shell 2 and the rod guide 6 is moved upward. , And the upper end of the outer shell 2 is swaged to fix the holding plate 10 together with the rod guide 6 so as to be positioned at a predetermined location.

In the above description, a seal groove 11 is formed on the outer periphery of the holding plate 10 on the front surface side, and a seal 12 is interposed in the seal groove 11 to seal the caulked portion of the outer shell 2. However, when the required degree of sealing is obtained by caulking, the seal groove 11 and the seal 12 may be omitted.

As a result, the caulking force of the outer shell 2 is directly applied to the holding plate 10 of the rod seal 7, so that the caulking force causes deformation or breakage of components inside the hydraulic shock absorber 1, or A reduction in the pressing force against the cylinder 3 due to the bulging of the member interposed in the caulking portion is eliminated.

Further, in this way, an annular recess 13 on the inner peripheral side surrounded by the holding plate 10 having the piston rod 5, the rod guide 6 and the rod seal 7 is provided at the upper inner end of the main body portion 4. An annular recess 14 on the outer peripheral side is formed between the outer shell 2 and the rod guide 6 by surrounding the annular recess 13.

The annular recesses 13 and 14 on the inner and outer peripheral sides are
The upper surface of the rod guide 6 is communicated with each other through a communication port 15 formed by recessing the upper surface of the rod guide 6, and the outer annular recess 14 is formed by recessing the outer peripheral surface of the rod guide 6 in a groove shape. Through the drain port 16 to the reservoir chamber R.

Further, inside the annular recess 14 on the outer peripheral side, a check seal 17 which opens from the communication port 15 toward the drain port 16 is provided with a holding plate 1 for the rod seal 7.
It is baked at 0 and installed.

Thus, when the oil chamber A on the rod side is compressed by the piston in accordance with the extension operation of the hydraulic shock absorber 1, a part of the internal working oil is moved from the sliding contact gap between the piston rod 5 and the rod guide 6 to the inside. It enters the annular recess 13 on the peripheral side.

Then, the fluid flows from the communication port 15 and the drain port 16 into the reservoir chamber R between the outer shell 2 and the cylinder 3 while pushing and opening the check seal 17 through the annular recess 14 on the outer peripheral side.

At this time, by arranging the communication port 15 and the drain port 16 so as to be shifted from each other as shown by a solid line and a broken line in FIG.
The check seal 17 is pushed open from the communication port 15 and does not directly go to the drain port 16, but flows toward the drain port 16 while flowing along the circumferential direction in the annular recess 14 on the outer peripheral side.

As a result, the above-mentioned hydraulic oil uniformly adheres to the entire periphery of the lip of the check seal 17, and the oil chamber A on the rod side is moved with the shift of the hydraulic shock absorber 1 to the compression operation.
Becomes slightly negative pressure, and the effect of preventing the suction of gas from the reservoir chamber R when the check seal 17 is closed is improved.

Although not shown, the drain port 16 may be tilted with respect to the axis of the rod guide 6 in combination with the above or independently to increase the opening area at the outlet end. Of the check seal 17 is facilitated by keeping the back pressure low.

Thus, the formation of an oil film on the surface of the piston rod 5 is ensured, and the rod seal 7 and the bearing 9 are formed.
, The lubricating property and the sealing function can be kept good, and the desired desired extension side damping characteristic can be always secured.

On the other hand, when the hydraulic shock absorber 1 performs the compression operation, the hydraulic oil pressure in the rod-side oil chamber A becomes slightly negative, so the upper part of the reservoir chamber R through the reverse path to that during the extension operation. Gas into the annular recess 13 on the inner peripheral side.

However, in this case, since the check seal 17 acts on the closing side to prevent the suction of the gas, the holding of the hydraulic oil in the annular recess 13 on the inner peripheral side is ensured. Thus, the lubricating and sealing properties with the rod seal 7 and the lubricating property with the bearing 9 are maintained to secure the compression-side damping characteristics.

Nevertheless, in these cases, however, in these cases, the rod seal 7 comes into sliding contact with the piston rod 5 and receives a repeated load in the vertical direction due to friction at all. If the holding portion 18 of the rod seal 7 is simply covered and baked on the side, the rod seal 7 may be peeled off and damaged.

In this regard, in this embodiment, FIG.
As can be seen from FIG. 3 and FIG. 3, a thin, flange-shaped extension portion 19 is provided on the inner peripheral side of the holding plate 10 formed in a perforated disk shape.
Is formed, and the holding portion 18 of the rod seal 7 is
9 and integrally attached by baking.

Thus, the holding portion 1 of the rod seal 7
Since the cover 8 extends over the extension 19 and is embedded on the same surface as or close to the holding plate 10, peeling of the rod seal 7 from the holding plate 10 and associated loss are also prevented.

In addition to the above, concentric ridges 20 are provided on the front and back surfaces of the extension 19 of the holding plate 10 as shown in FIGS. Extension portion 19 and holding portion 1 of rod seal 7
8 has a large joint area.

In this manner, since the mutual bonding force between the rod seal 7 and the holding plate 10 increases, the peeling of the rod seal 7 and the accompanying loss can be more effectively prevented.

4 and 5, instead of the concentric ridge 20, the extension 19a having a ridge 20a divided in a zigzag manner in the circumferential direction.
By using the holding plate 10a provided with the above, even if a part of the holding part 18 of the rod seal 7 is peeled off, the above-mentioned peeling extends over the entire circumference by the staggered ridge 20a. Can be prevented.

Further, as in the embodiment shown in FIGS. 6 and 7, if the holding plate 10b provided with the extension 19b having the radial ridge 20b is used, the piston rod 5 to be sealed rotates. In this case, the rod seal 7 can be prevented from coming off and rotating together with the torque generated by the friction generated by increasing the joint area in the rotation direction.

[0041]

As described above, according to the first aspect of the present invention, a thin flange-like extension is formed on the inner peripheral side of the holding plate for holding the rod seal, and the rod seal is formed on this extension. Since the holding portion of the rod seal is inserted and fixed, the holding portion of the rod seal covers the extended portion of the holding plate and is embedded on the same surface or in a state close to the same surface. Defects can be effectively prevented.

According to the second aspect of the present invention, concentric ridges are formed on the front and back of the flange-like extension formed on the inner peripheral side of the holding plate, and these ridges are used to hold the rod seal. Since the inner surface of the portion is bitten and fixed, the joint area between the holding plate and the rod seal is increased, so that peeling of the rod seal from the holding plate and associated loss can be more effectively prevented.

According to the third aspect of the present invention, the ridges are formed in a zigzag pattern on the front and back sides of the flange-shaped extension formed on the inner peripheral side of the holding plate in a circumferential direction, and these ridges are rod seals. Even if a part of the holding part of the rod seal is peeled off by being cut into the inner surface of the holding part of Can be prevented.

According to the fourth aspect of the present invention, ridges are formed radially on the front and back of a flange-shaped extension formed on the inner peripheral side of the holding plate, and these ridges are used to hold the rod seal. When the piston rod to be sealed is secured by being cut into the inner surface of the part, the rod seal peels off due to the torque generated by the friction when the piston rod to be sealed rotates, and the joint area in the rotation direction is reduced by rotating together. It can be prevented by increasing it.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal front view showing an embodiment of a rod seal structure in an upper portion of a main body of a hydraulic shock absorber according to the present invention.

FIG. 2 is a plan view of only the holding plate taken out of the rod seal structure and viewed from above.

FIG. 3 is a vertical sectional front view of the same holding plate as viewed from the front.

FIG. 4 is a plan view showing another embodiment of a holding plate having a rod seal structure according to the present invention.

FIG. 5 is a vertical sectional front view of the same holding plate as viewed from the front.

FIG. 6 is a plan view showing still another embodiment of the holding plate having the rod seal structure according to the present invention.

FIG. 7 is a longitudinal sectional front view of the same holding plate as viewed from the front.

FIG. 8 is a partial longitudinal sectional front view showing a rod seal structure in a hydraulic shock absorber as a conventional example.

FIG. 9 is a partial longitudinal sectional front view showing a rod seal structure in an improved conventional hydraulic shock absorber.

[Explanation of symbols]

 A Oil chamber on rod side R Reservoir chamber 1 Hydraulic shock absorber 2 Outer shell 3 Cylinder 5 Piston rod 6 Rod guide 7 Rod seal 8 Reinforcement rib 10, 10a, 10b Holding plate 18 Rod seal holding section 19, 19a, 19b Inner peripheral extension 20 Concentric ridge 20a Staggered ridge 20b Radial ridge

Claims (4)

[Claims] 1. A holding plate provided with a rod seal on the inner peripheral side is placed directly or indirectly on a cylinder end to crimp an outer shell, and a crimping force is applied directly to the cylinder through the holding plate. In the rod seal structure of the hydraulic shock absorber holding the rod seal by the holding plate, a thin flange-shaped extension is formed on the inner peripheral side of the holding plate, and the holding portion of the rod seal is inserted into this extension. A rod seal structure for a hydraulic shock absorber, wherein the rod seal structure is fixed. 2. A concentric ridge is formed on the front and back of a flange-shaped extension formed on the inner peripheral side of the holding plate, and these ridges are bite into the inner surface of the holding portion of the rod seal and are fixed. Claim 1
By the rod seal structure of the hydraulic shock absorber. 3. A ridge is formed in a zigzag manner on the front and back sides of a flange-shaped extension formed on the inner peripheral side of the holding plate in a circumferential direction, and these ridges are cut into the inner surface of the holding portion of the rod seal. 2. A rod seal structure for a hydraulic shock absorber according to claim 1, wherein said rod seal structure is fixed by being fixed. 4. A ridge is formed radially on the front and back of a flange-shaped extension formed on the inner peripheral side of the holding plate, and these ridges are bitten into the inner surface of the holding portion of the rod seal and fixed. A rod seal structure for a hydraulic shock absorber according to claim 1.