JP2002070914A - Hydraulic shock absorber and method of manufacturing rod guide used in the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the strength of an oil seal holding portion of a rod guide and facilitate the housing of an outer guide portion and an inner guide portion between an inner tube and a piston rod. SOLUTION: A rod guide 9 is formed through deep drawing work and the like on a single circular steel plate 9'. An outer guide portion 11 and an inner guide portion 12 of the rod guide 9 are formed thinner than an oil seal holding portion 10 according to the size of a rod guide housing space S between an inner tube 3 and a piston rod 7. The oil seal holding portion 10 is formed thick to the substantially same plate thickness as the circular steel plate 9'. A crimped portion 1A of an outer tube 1 and the oil seal holding portion 10 hold an oil seal 15 in between.

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 suitable for damping the vibration of a vehicle such as a passenger car and a method of manufacturing a rod guide used therefor.

[0002]

2. Description of the Related Art In general, a hydraulic shock absorber has an outer cylinder having one end closed and an oil seal provided at the other end, and an annular reservoir chamber formed between the outer cylinder and the outer cylinder. An inner cylinder, a piston rod one end of which is inserted into the inner cylinder and the other end of which projects outward from the outer cylinder via an oil seal, and which is fixed to the inner peripheral side of the inner cylinder and slides the piston rod. And a rod guide for guiding as possible (for example, Japanese Patent Application Laid-Open No. 9-257079).

In this type of conventional hydraulic shock absorber, for example, one end of an outer cylinder is mounted on the axle side of a vehicle, and the other end of the piston rod is mounted on the vehicle body side of the vehicle. When vibration is externally applied to the vehicle, the piston rod expands and contracts, and the oil liquid flows between the bottom oil chamber and the rod oil chamber formed in the inner cylinder, thereby generating a damping force. The mechanism generates a damping force to dampen the vibration of the vehicle.

The rod guide is formed in a cylindrical shape by press-forming a single plate material, and the outer peripheral side is an oil seal holding portion. The oil seal sandwiching portion fits on the inner peripheral side of the outer cylinder and abuts on the other end side of the inner cylinder. In this state, the other end side of the outer cylinder is swaged to form the oil seal sandwiching portion. The oil seal is sandwiched between the outer cylinder and the outer cylinder.

[0005] The rod guide has an inner peripheral side formed in a double cylindrical shape having an outer guide portion and an inner guide portion. Of these guide portions, the outer guide portion is press-fitted to the inner peripheral side of the inner cylinder, and a bush that slides with the rod guide is fitted and provided on the inner peripheral side of the inner guide portion. The rod is slidably guided in the axial direction.

[0006]

By the way, the hydraulic shock absorber according to the prior art described above is provided with the other end side (open end side) of the outer cylinder.
By caulking, the oil seal is held between the outer cylinder and the oil seal holding section of the rod guide, so that the oil seal holding section receives an axial caulking load from the outer cylinder. Is done. Further, a lateral force directed in the radial direction is applied to the oil seal holding portion via the piston rod. Therefore, it is necessary to form the oil seal holding portion to have a large thickness so as to secure the strength of the oil seal holding portion against the caulking load.

However, in this conventional technique, the rod guide is formed by press-forming a plate material having a uniform plate thickness. For this reason, if the oil seal sandwiching portion is formed to be thick as described above, the outer guide portion and the inner guide portion must also be formed to be thicker, and each of these guide portions is formed together with the bush by the inner cylinder and the piston. There is a problem that it is difficult to secure an accommodation space for accommodating between the rod and the rod, and the assembling work of the rod guide becomes difficult.

On the other hand, if the entirety of the rod guide is formed thin in order to accommodate the outer guide portion and the inner guide portion between the inner cylinder and the piston rod, the strength of the oil seal holding portion is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. It is an object of the present invention to increase the strength of an oil seal sandwiching portion of a rod guide and to connect an outer guide portion and an inner guide portion to an inner cylinder. It is an object of the present invention to provide a hydraulic shock absorber which can be easily housed between a piston rod and a piston rod, and which can improve an assembling operation of the rod guide, and a method of manufacturing a rod guide used therein.

[0010]

In order to solve the above-mentioned problems, a hydraulic shock absorber according to the present invention comprises: an outer cylinder having one end closed and an oil seal provided at the other end; An inner cylinder forming an annular reservoir chamber with the outer cylinder, a piston rod having one end inserted into the inner cylinder and the other end protruding outside from the outer cylinder via an oil seal, and a plate material. A rod guide is formed by press forming, is fixed to the inner peripheral side of the inner cylinder, and guides the piston rod slidably.

A feature of the structure adopted by the first aspect of the present invention is that the rod guide is fitted on the inner peripheral side of the outer cylinder and abuts on the other end side of the inner cylinder to be in contact with the outer cylinder. An oil seal sandwiching portion for sandwiching an oil seal therebetween, an outer guide portion formed integrally with the oil seal sandwiching portion and fitted on the inner peripheral side of the inner cylinder, and an end guide of the outer guide portion as the outer guide. The inner guide portion is formed by folding back so as to overlap the portion and is provided with a bearing portion sliding on the inner peripheral side with the piston rod, and the plate thickness of the outer guide portion and the plate thickness of the inner guide portion are provided. Is that the oil seal holding portion is formed to be thinner than the plate thickness.

With this configuration, the outer guide portion and the inner guide portion of the rod guide can be formed to be thinner than the oil seal holding portion, and each of these guide portions together with the bearing portion can be formed between the inner cylinder and the piston rod. Can be easily accommodated. Further, the oil seal holding portion of the rod guide can be formed thicker with a greater plate thickness than the outer guide portion and the inner guide portion, and the strength of the oil seal holding portion can be increased. Therefore, the oil seal holding portion can stably hold the oil seal with the outer cylinder. Further, the oil seal holding portion can stably support a radial force from the piston rod in the radial direction.

The method of manufacturing a rod guide used for a hydraulic shock absorber according to the second aspect of the present invention is a method of manufacturing a rod guide, wherein a circular steel plate serving as a material for the rod guide is subjected to deep drawing so that one side in the thickness direction of the circular steel plate. A guide portion forming step of forming an outer guide portion projecting toward the outer guide portion and an inner guide portion reduced in diameter from the outer guide portion and projecting toward one side in the thickness direction of the circular steel plate; and the inner guide portion Turning the inner guide portion by pressing the inner steel plate toward the other side in the thickness direction of the circular steel plate, and expanding the oil from the outer guide portion by performing deep drawing on the outer peripheral side of the circular steel plate. An oil seal sandwiching portion forming step of forming a seal sandwiching portion, and a contacting step of overlapping the inner guide portion with the outer guide portion by pressing the inner guide portion outward in the radial direction. Comprises an oil seal clamping portion processing step bending into a curved shape by folding back the outer diameter side of the oil seal holding portions, and a drilling step of applying drilling for rod guide inserted through the inner guide portion.

According to this structure, the outer guide portion thinner than the circular steel plate can be formed by performing deep drawing on the circular steel plate, and the inner guide portion thinner than the circular steel plate can be formed. Then, by folding the inner guide portion and pressing it outward in the radial direction, the inner guide portion can be overlapped with the outer guide portion and brought into close contact therewith. Further, by subjecting the outer peripheral side of the circular steel plate to deep drawing, an oil seal sandwiching portion having substantially the same thickness as the circular steel plate can be formed. Furthermore, a rod guide can be formed by turning the outer diameter side of the oil seal holding portion and bending it in a curved shape, and forming a hole for inserting the rod guide into the inner guide portion.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a hydraulic shock absorber according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings of FIGS.

Reference numeral 1 denotes an outer cylinder that constitutes a main body of the hydraulic shock absorber and has an oil liquid sealed therein. The lower end, which is one end side of the outer cylinder 1, is closed by a bottom cap 2. Further, a plurality of caulking portions 1A (only one is shown) are provided at an upper end side, which is the other end side of the outer cylinder 1, at intervals in the circumferential direction. It is sandwiched between the guide 9.

Reference numeral 3 denotes an inner cylinder which is coaxially disposed in the outer cylinder 1 and has an oil liquid sealed therein. The inner cylinder 3 has a lower end fitted to a bottom valve 8 described later, and an upper end A rod guide 9 is provided. The inner cylinder 3 defines an annular reservoir chamber A between the inner cylinder 3 and the outer cylinder 1, and gas is sealed in the reservoir chamber A together with the oil liquid. As shown in FIG. 2, the inner diameter D1 of the inner cylinder 3 is, for example, about 25 to 35 m in a standard specification.
In the embodiment of the present invention, 30 mm is used. Further, the inner cylinder 3 has a lower end side end surface 3A serving as one end side end surface and an upper end side end surface 3B serving as the other end side end surface.

Reference numeral 4 denotes a piston slidably fitted on the inner peripheral side of the inner cylinder 3. The piston 4 divides the inner cylinder 3 into a bottom oil chamber B and a rod oil chamber C. It is defined. The piston 4 has a disk valve 5 for generating a damping force on the extension side and a disk valve 6 for flowing the oil liquid on the reduction side.
Are provided. The disc valves 5 and 6 open when the piston rod 7 expands and contracts, respectively, and generate a damping force by flowing an oil liquid between the bottom oil chamber B and the rod oil chamber C. Things.

Reference numeral 7 denotes a piston rod inserted into the inner cylinder 3, and the lower end of the piston rod 7 is fixed to the inner peripheral side of the piston 4. Further, the upper end side of the piston rod 7 projects outside the outer cylinder 1 via the rod guide 9 and the like,
For example, it is attached to the body side of an automobile.

Also, as shown in FIG.
The outer diameter D2 of the standard specification is, for example, 18 to 25 mm.
Thus, in the embodiment of the present invention, a 20 mm one is taken. For this reason, the piston rod 7 has an inner diameter D1 (3
A rod guide housing space S having a dimension of, for example, about 5 mm is defined between the inner guide 3 and the inner cylinder 3 having a length of about 0 mm. In the rod guide accommodating space S, an outer guide 11 and an inner guide 12 of the rod guide 9 described later are accommodated together with the bush 14.

Reference numeral 8 denotes a bottom valve which is located above the bottom cap 2 and is provided at the lower end of the inner cylinder 3.
The oil liquid (oil liquid corresponding to the integral volume of the piston rod 7) flows into the reservoir chamber A side to generate a damping force. On the other hand, when the piston rod 7 is extended, the bottom valve 8 is held in the open state, and the oil liquid in the reservoir chamber A flows into the bottom oil chamber B without generating a damping force.

Reference numeral 9 denotes a rod guide provided on the upper end side of the inner cylinder 3. The rod guide 9 is formed by pressing a single steel plate or the like having a smooth surface by deep drawing or the like, as shown in FIGS. It is formed in a cylindrical shape as shown in FIG. The rod guide 9 is provided with an oil seal holding portion 10 described later,
The outer guide 11 and the inner guide 12 are provided.

Reference numeral 10 denotes an oil seal holding portion which holds the oil seal 15 between the outer cylinder 1 and the oil seal holding portion 10. The oil seal holding portion 10 is fitted on the inner peripheral side of the outer cylinder 1. 1
0A, an inclined portion 10B obliquely inclined inward in the radial direction from the upper end of the fitting portion 10A, and a connecting portion which is reduced in diameter inward from the end of the inclined portion 10B and connected to the outer guide portion 11. 10C.

The annular plate 15A of the oil seal 15 is provided on the upper end side of the connecting portion 10C of the oil seal holding portion 10.
And a valve seat 10C2 which is located on the inner peripheral side of the seal contact step 10C1 and on which the lip 15C of the oil seal 15 is separated and seated. Further, the lower end side of the connecting portion 10C is an inner cylinder contact step 10C3 which contacts the upper end surface 3B of the inner cylinder 3.

The oil seal holding portion 10 receives the axial caulking load applied to the oil seal 15 from the caulking portion 1A of the outer cylinder 1 by the connecting portion 10C, and the oil seal between the oil caulking portion 1A and the oil caulking portion 1A. 15 is held.

Here, as shown in FIG. 3, the thickness d1 of the oil seal sandwiching portion 10 is, for example, 2.3 to 3.0 m.
m, preferably about 2.5 mm. Also,
A plurality of communication holes 10D (only one is shown) are formed in the connecting portion 10C of the oil seal holding portion 10 at a distance from each other in the circumferential direction. 11 is an outer guide portion provided on the inner peripheral side of an oil seal sandwiching portion 10 constituting the rod guide 9, and the outer guide portion 11 is provided with a lip portion 15C of the oil seal 15. , Oil seal holding part 1
The inner cylinder 3 is press-fitted into the inner peripheral side of the inner cylinder 3 and fixed there.

Here, as shown in FIG.
Reference numeral 1 denotes an inner cylinder contact step 10C3 of the oil seal holding portion 10.
The thickness d21 is about 2 mm at the upper end near the end, and about 1.75 m at the lower end near the turn-back portion 13.
The thickness d22 is about m. The outer guide portion 11 has a thickness d2 of about 1.9 mm on average, and a thickness d1 of the oil seal holding portion 10 (about 2.
5 mm) (d2 <d1).

Numeral 12 designates an inner guide provided on the inner peripheral side of the outer guide 11. The inner guide 12 is folded from the lower end of the outer guide 11 into a substantially U-shape via a folded portion 13. And extends upward, and is superimposed and closely attached to the inner peripheral surface of the outer guide portion 11. And the inner guide part 1
Reference numeral 2 denotes a rod insertion hole 12A on the inner peripheral side, and the piston rod 7 is inserted into the rod insertion hole 12A to guide the piston rod 7 in the axial direction via a bush 14 described later.

Here, as shown in FIG.
2 is about 1.75 m on the lower end side near the turn-back portion 13
The thickness d31 is about m, and the thickness d32 is about 1.5 mm at the upper end near the rod insertion hole 12A. The inner guide portion 12 has an average thickness d3 of about 1.6 mm, and is formed thinner (d3 <d1) than the thickness d1 (about 2.5 mm) of the oil seal sandwiching portion 10. Have been.

For this reason, the inner guide 12 has a thickness d2.
(About 1.9 mm) and a bush 14 having a plate thickness d4 (about 1.5 mm) as described later.
Together with the rod guide housing space S (about 5 mm) with almost no gap.

Reference numeral 14 denotes an inner guide portion 12 of the rod guide 9.
The bush 14 is formed by using, for example, a resin material having lubricity, and guides the piston rod 7 slidably in the axial direction. . Also, as shown in FIG.
Is set to, for example, about 1.5 mm.

Reference numeral 15 denotes an oil seal provided between the caulked portion 1A of the outer cylinder 1 and the rod guide 9. The oil seal 15 is an annular plate 1 fitted on the inner peripheral side of the outer cylinder 1.
5A and a cylindrical rod seal 15B made of an elastic material such as rubber and fixed to the inner peripheral side of the annular plate 15A.
And a lip portion 15C as a check valve integrally formed on the outer peripheral side of the rod seal 15B. The oil seal 15 defines an annular oil reservoir 16 between the oil seal 15 and the rod guide 9.

Here, the oil seal 15 is caulked and fixed by the caulking portion 1A of the outer cylinder 1 so that the annular plate 15A abuts against the seal abutting end 10C1 of the rod guide 9.
The oil seal 15 slides the rod seal 15B on the outer peripheral side of the piston rod 7 with a tight allowance, and seals the gap between the oil seal 15 and the piston rod 7 in a gas-liquid tight manner.

The lip 15C of the oil seal 15
Is in contact with the valve seat portion 10C2 of the rod guide 9 so as to be able to be detached and seated. The lip portion 15C is used when the oil liquid in the rod-side oil chamber C or air mixed in the oil liquid leaks into the oil reservoir chamber 16 between the piston rod 7 and the bush 14. The valve is opened, and the oil or the like is released into the reservoir chamber A through the communication hole 10D of the rod guide 9.

Further, the annular plate 15A of the oil seal 15
A seal ring 15D is fixedly provided on the outer peripheral side, and the seal ring 15D prevents oil liquid and gas in the reservoir chamber A from leaking outside from between the outer cylinder 1 and the annular plate 15A. It is.

Reference numeral 17 denotes a bump rubber receiver provided on the upper end side of the outer cylinder 1. The bump rubber receiver 17 is provided on the upper end side of the piston rod 7 when the piston rod 7 is greatly reduced. (Not shown)
It absorbs vibrations of automobiles.

The hydraulic shock absorber according to the present embodiment has the above-described structure. When the piston rod 7 is in the extension stroke, the pressure in the rod-side oil chamber C becomes high, and the oil in the oil chamber C becomes high. The liquid flows through the disc valve 5 to the bottom oil chamber B.
The damping force is generated by flowing into the inside. And
An amount of oil liquid corresponding to the integral volume of the piston rod 7 advanced from the inner cylinder 3 is supplied from the reservoir chamber A to the bottom valve 8.
Flows into the bottom side oil chamber B via the

When the piston rod 7 is in the reduction stroke, the pressure in the bottom oil chamber B becomes high, and the oil in the oil chamber B flows out into the rod oil chamber C via the disc valve 6. . Then, the piston rod 7 that has entered the inner cylinder 3
An amount of oil liquid corresponding to the volume of the fluid flowing out flows out of the bottom oil chamber B into the reservoir chamber A via the bottom valve 8 to generate a damping force.

Next, a method of manufacturing the rod guide 9 will be described with reference to FIGS. 4 to 12. First, as shown in FIG.
A circular steel plate 9 'having a thickness of about 2.5 mm is prepared.

Next, as shown in FIG. 5, by subjecting the circular steel plate 9 'to deep drawing, the central portion of the circular steel plate 9' is projected so as to be thinly extended to one side (downward) in the plate thickness direction. Then, an outer guide portion 11 'having a bottom portion 11A' is formed (first guide portion forming step). As a result, the outer guide portion 11 'can be formed thinner than the circular steel plate 9', and its thickness can be reduced to d2 (about 1.9 mm).

Then, as shown in FIG.
By subjecting the bottom portion 11A 'of 1' to deep drawing, the center portion of the bottom portion 11A 'of the outer guide portion 11' is projected so as to extend thinly downward, and the diameter of the bottom portion 12A 'is reduced from the outer guide portion 11'. Forming the inner guide portion 12 'having
(Second guide part forming step). As a result, the inner guide portion 12 'can be formed thinner than the outer guide portion 11', and its thickness can be reduced to d3 (about 1.6 mm).

Next, as shown in FIG.
2 ′ is pressed toward the other side (upward) in the thickness direction of the circular steel plate 9 ′ toward the inner peripheral side of the outer guide portion 11 ′.
This inner guide portion 12 'is folded back. At this time, the bottom portion 11A 'of the outer guide portion 11' is formed as a folded portion 13 '(turning step).

Next, as shown in FIG. 8, by subjecting the circular steel plate 9 'to deep drawing, the outer peripheral portion of the circular steel plate 9' is projected upward while maintaining the thickness d1. An oil seal sandwiching portion 10 '(connecting portion 10C') whose diameter is increased upward from the guide portion 11 'through an inner cylinder contact step 10C3' is formed. The oil seal sandwiching portion 10 'has an outer diameter dimension a and a depth dimension b. (First oil seal sandwiching part forming step).

Then, as shown in FIG. 9, the inner diameter of the oil seal holding portion 10 'is reduced to a' by processing such as pressing the oil seal holding portion 10 'inward in the radial direction (a>a'). ), And at the same time, a correction for expanding the depth dimension to b ′ (b ′> b) is performed. (Second oil seal sandwiching part forming step).

Next, as shown in FIG. 10, the inner guide portion 12 'is pressed radially outward to expand the diameter,
The inner guide portion 12 'is overlapped with and adhered to the outer guide portion 11' (adhesion step).

Further, as shown in FIG. 11, the outer diameter side of the oil seal holding portion 10 is folded while being bent while maintaining the plate thickness dimension d1 to be curved.
The 0 'fitting portion 10A' is formed (oil seal sandwiching portion processing step).

Further, the oil seal sandwiching portion 10 ', the outer guide portion 11', and the inner guide portion 12 'are subjected to press working or the like to adjust the shape of the rod guide 9 (shaping step). Finally, as shown in FIG. 12, the inner guide portion 12 is drilled to form the rod insertion hole 12.
A is formed (drilling step).

Since the oil seal holding portion 10 of the rod guide 9 receives the axial caulking load from the outer cylinder 1, the thickness d1 of the oil seal holding portion 10 is increased to at least about 2.5 mm. However, it is necessary to ensure the strength of the oil seal holding portion 10 against the caulking load.

However, in the standard type hydraulic shock absorber, the rod guide accommodating space S defined between the inner cylinder 3 and the piston rod 7 is secured only about 5 mm.
The thickness d2 of the outer guide portion 11 and the thickness d3 of the inner guide portion 12 are about 2.
If it is set to 5 mm, it becomes difficult to accommodate each of the guide portions 11 and 12 together with the bush 14 in the rod accommodation space S.

Therefore, in this embodiment, the circular steel plate 9 '
As described above, the thickness d2 (about 1.9 mm) of the outer guide portion 11 and the thickness d3 (about 1.6 mm) of the inner guide portion 12 are subjected to deep drawing or the like as described above. The outer guide portion 11 and the inner guide portion 12 are connected to the bush 14 when the rod guide 9 is assembled.
Can be easily accommodated in the rod guide accommodating space S, and the workability at the time of assembling the rod guide 9 can be improved.

The oil seal holding portion 10 of the rod guide 9 can be formed to be thicker than the outer guide portion 11 and the inner guide portion 12, respectively, and a caulking load from the outer cylinder 1 added to the oil seal holding portion 10. On the other hand, the strength of the oil seal holding portion 10 can be sufficiently ensured, and the oil seal 15 can be stably held between the caulked portion 1A of the outer cylinder 1 and the oil seal holding portion 10. Also,
The oil seal holding portion 10 can also stably support the radial force from the piston rod 7 in the radial direction.

In the embodiment, the case where the bush 14 as a bearing portion is separately provided on the inner guide portion 12 of the rod guide 9 has been described as an example, but the present invention is not limited to this. The bearing portion may be formed by subjecting the inner peripheral portion of the inner guide portion to processing such as tetrafluoroethylene.

In the embodiment, the hydraulic shock absorber of an automobile has been described as an example. However, the present invention is not limited to this. For example, a hydraulic shock absorber used for various machines and buildings serving as vibration sources. May be used.

[0054]

As described above in detail, according to the first aspect of the present invention, the rod guide is formed by press-forming a plate material to form a cylindrical member including an oil seal holding portion, an outer guide portion, and an inner guide portion. The outer and inner guides are aligned with the gap between the inner cylinder and the piston rod. When the rod guide is assembled, each of these guide portions can be easily housed between the inner cylinder and the piston rod, thereby improving workability and the like. Further, the oil seal holding portion can be formed thicker with a larger plate thickness than the outer guide portion and the inner guide portion, and the strength of the oil seal holding portion can be increased. Can be stably sandwiched between the two.

According to the second aspect of the present invention, the rod guide forms the outer guide portion and the inner guide portion by subjecting the center of the circular steel plate to deep drawing, and the rod guide is deep drawn to the outer peripheral side of the circular steel plate. Since the oil seal holding portion is formed by performing the processing, the outer guide portion and the inner guide portion can be formed thinner than the oil seal holding portion,
In substantially the same manner as in the first aspect of the present invention, the workability at the time of assembling the rod guide can be improved, the strength of the oil seal holding portion is increased, and the oil seal is formed between the oil seal holding portion and the outer cylinder. It can be stably held.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a hydraulic shock absorber according to an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing a rod guide, an oil seal, and the like in FIG. 1 in an enlarged manner.

FIG. 3 is a sectional view showing the rod guide in FIG. 2 alone;

FIG. 4 is a sectional view showing a circular steel plate alone;

FIG. 5 is a cross-sectional view showing a state in which an outer guide portion is formed on a circular steel plate by a first guide portion forming step.

FIG. 6 is a sectional view showing a state in which an inner guide portion is formed on an outer guide portion by a second guide portion forming step.

FIG. 7 is a cross-sectional view showing a state in which an inner guide portion is turned back in a turning step.

FIG. 8 is a cross-sectional view showing a state in which an oil seal holding portion is formed on a circular steel plate by a first oil seal holding portion forming step.

FIG. 9 is a cross-sectional view showing a state in which the diameter of the oil seal holding portion is reduced by a second oil seal holding portion forming step.

FIG. 10 is a cross-sectional view showing a state in which an inner guide portion is brought into close contact with an outer guide portion by a contact process.

FIG. 11 is a cross-sectional view showing a state where an oil seal holding portion is bent in an oil seal holding portion processing step.

FIG. 12 is a cross-sectional view showing a state in which a rod insertion hole is formed in an inner guide portion by a drilling step.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer cylinder 3 Inner cylinder 3B Upper end side end face (other end side end face) 4 Piston 7 Piston rod 9 Rod guide 9 'Circular steel plate 10, 10' Oil seal sandwiching part 11, 11 'Outer guide part 12, 12' Inner guide part 12A Rod insertion hole 13, 13 'Folded part 14 Bush (bearing part) 15 Oil seal A Reservoir chamber S Rod guide accommodation space

Claims (2)

[Claims] 1. An outer cylinder provided with an oil seal at one end and an oil seal at the other end, an inner cylinder provided in the outer cylinder and forming an annular reservoir chamber with the outer cylinder, A piston rod inserted into the inner cylinder, the other end of which protrudes outside from the outer cylinder via an oil seal; and a plate formed by press-forming a plate material and fixed to the inner peripheral side of the inner cylinder. A hydraulic shock absorber comprising a rod guide that slidably guides the piston rod, wherein the rod guide fits on the inner peripheral side of the outer cylinder and abuts on the other end side of the inner cylinder. An oil seal holding portion for holding the oil seal between the outer guide portion, an outer guide portion formed integrally with the oil seal holding portion and fitted to the inner peripheral side of the inner cylinder, and an end portion side of the outer guide portion. Fold back so that it overlaps the outer guide And an inner guide portion provided with a bearing portion that slides on the inner peripheral side with the piston rod. The plate thickness of the outer guide portion and the plate thickness of the inner guide portion are the plate thickness of the oil seal holding portion. A hydraulic shock absorber characterized by being formed thinner than thick. 2. An outer guide portion protruding toward one side in the thickness direction of the circular steel plate by subjecting the center of a circular steel plate as a material for the rod guide to deep drawing, and reducing the diameter from the outer guide portion. A guide forming step of forming an inner guide protruding toward one side in the thickness direction of the circular steel plate, and pressing the inner guide toward the other side in the thickness direction of the circular steel plate to form the inner side. A turning step of turning back the guide portion; an oil seal holding portion forming step of forming an oil seal holding portion having a diameter increased from the outer guide portion by performing a deep drawing process on an outer peripheral side of the circular steel plate; and the inner guide portion. A step of overlapping the inner guide portion with the outer guide portion by pressing the oil seal radially outward, and turning the outer diameter side of the oil seal sandwiching portion to bend the oil seal in a curved shape. Over and Le clamping portion processing step, the rod guide method of production using the inner guide portion to the hydraulic shock absorber comprising a drilling step of applying drilling for rod guide insertion.