KR100265678B1 - Hydraulic shock absorber - Google Patents

Abstract

An object of the present invention is to provide a hydraulic shock absorber that can reduce the machining cost of a rod guide.

Longitudinal grooves 77a concave outward from the inner circumferential surface of the annular upright portion 77 are formed in the annular upright portion 77 of the rod guide 7 which abuts by bending to the outside at the time of valve opening of the check lip 11d. At the same time, the flange portion 72 supporting the oil seal 11 is formed with a radial groove 72b recessed downward from the abutting surface of the oil seal 11 and communicating with the longitudinal groove 77a. The outline of (7) is formed into a polygon having a plurality of large diameter portions 72a which abut against the inner circumferential surface of the outer tube 5 and a plurality of small diameter portions 72c which form a gap a between the inner circumferential surface of the outer tube 5. The radial groove 72b and the longitudinal groove 77a are formed in the small diameter portion 72c.

Description

Hydraulic shock absorber

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to hydraulic shock absorbers for use in vehicles, and more particularly to improvements in the structure of road guide sections.

Conventionally, as a check seal structure in such a hydraulic shock absorber, there exist some which were described in Unexamined-Japanese-Patent No. 8-82336 regarding the source of this applicant. This source is made to solve the problem of the conventional hydraulic shock absorber (Japanese Utility Model Publication No. 2-110730, Utility Model Publication 4-27235) mentioned below.

That is, as described in FIG. 4 of JP-A-2-110730, a reservoir chamber in which gas is enclosed between a cylinder tube and an outer tube formed inside and outside is formed, and the inner circumference of the upper end of the cylinder tube and the outer tube is formed. Rod guides each inserted to guide the sliding movement of the piston rod are provided, and an annular recess communicating with the reservoir chamber is formed on the inner circumferential side upper surface of the rod guide by a communication path, and in the opening of the outer tube at the top of the rod guide. A rod seal that sealably slides between the opening inner circumferential surface of the outer tube and the outer circumferential surface of the piston rod and the reservoir section 27 in the recess 22 of the rod guide 21 as shown in FIG. 11. To prevent gas from entering the concave portion 22 via the communication path 23 formed on the upper surface side of the rod guide 21. There are oil seal having a check lip (24) of the cut type is in sandwiched structure.

In addition, what was described in FIG. 1 of Unexamined-Japanese-Patent No. 3-68649, and FIG. 5 of Unexamined-Japanese-Patent No. 4-27235 is the said communication as showing the principal part cross section in FIG. 12, FIG. The opening of the furnace 23 differs from that described in FIG. 1 of Japanese Utility Model Laid-Open No. 2-110730 in that the opening is formed at the same level position as the seal surface 26 on which the check lip 24 abuts. . Moreover, what was described in FIG. 5 of Unexamined-Japanese-Patent No. 4-27235 differs from another in that the rod guide 21 is formed by press molding of a board | plate material.

However, in the conventional hydraulic shock absorber described in FIG. 4 of JP-A-2-110730, the communication path 23 is formed on the upper surface side of the rod guide 21 as described above. Since it is a structure, there existed a problem as described below.

That is, when the internal pressure of the concave portion 22 becomes higher than a certain pressure, as shown in the sectional view of the main portion of Fig. 11, the check lip 24 is bent outward to open between the seal surfaces 26 that have been in contact with it until then. Although the hydraulic oil in the recess 22 flows out from the opening via the communication path 23 to the reservoir chamber 27 side, at this time, the inner diameter of the recess 22 in the rod guide 21 is set in terms of size or strength. In order to reduce the diameter of the check lip 24, the outer circumferential edge of the check lip 24 abuts against the inner circumferential surface of the recess 22, thereby blocking the flow path in the direction of the communication path 23 to check the check lip 24. There is a possibility that the gas removal in the direction of the reservoir chamber 27 and the reflux function of the working oil may not be exerted, thereby degrading performance and durability.

In addition, if the inner diameter of the check lip 24 is reduced in size so as to avoid the abutment of the check lip 24 with respect to the inner peripheral surface of the recess 22 in the rod guide 21, the performance decrease due to the change in the rubber stiffness is caused. At the same time, the inability to share parts creates another problem, which is disadvantageous in terms of cost.

On the other hand, what was described in FIG. 1 of Unexamined-Japanese-Patent No. 3-68649, and FIG. 5 of Unexamined-Japanese-Patent No. 4-27235, is shown in the main part cross section of FIG. 12 and FIG. Since the opening of 23 is formed in the same level position as the seal surface 26 which the check lip 24 abuts, the above problem does not occur, but to the same level as the seal surface 26 shown by the dashed-dotted line. Since the working oil is not stored in the recess 22 outside, there is a problem that durability against the prevention of deterioration due to wetting of the check lip 24 due to the working oil or cooling action cannot be maintained.

Thus, in FIG. 6 of Japanese Patent Laid-Open No. 8-82336 relating to the source of the applicant, as shown in FIGS. 14 and 15, the check lip 11d is moved outward when the valve is opened. A part of the inner circumferential surface of the annular upright portion 77 in the rod guide 7 which abuts by bending, and communicates with the longitudinal groove 77a concave outward from the abutting surface of the check lip 11d and the longitudinal groove 77a. In this case, the radial groove 72b is formed on the upper surface side of the flange portion 72 by press molding. (In addition, in this prior art example, the same code | symbol was used for the same component as embodiment of this invention.)

That is, as mentioned above, since the flow of hydraulic fluid between the oil storage chamber D and the reservoir chamber C is always maintained by the longitudinal groove 77a and the radial groove 72b, the valve of the check lip 11d. When opening, the hydraulic oil in the oil reservoir D can be returned to the reservoir chamber C via the longitudinal groove 77a and the radial groove 72b, thereby changing the inner diameter of the check lip 11d. The inner diameter of the oil reservoir D in the rod guide 7 can be reduced, and the cost can be reduced by the common use of the oil seal 11, and the radial groove 72b has an upper end of the rod guide 7. Since it is formed on the surface, it is possible to store the hydraulic oil in approximately the entire inside of the oil storage chamber D. As a result, during operation of the shock absorber, the entire check lip 11d is always immersed in the operating oil to prevent deterioration due to wetting or cooling action. We plan improvement of the durability by It can be obtained an effect that makes.

However, in Japanese Patent Laid-Open No. Hei 8-82336 of the applicant's source, as shown in Fig. 15, since the outer shape of the rod guide 7 is formed in a circular shape, there is a problem as described below.

That is, the outer side from the abutting surface of the check lip 11d to a part of the inner circumferential surface of the annular upright portion 77 in the rod guide 7 which abuts by the bending to the outside at the time of valve opening of the check lip 11d. And a radial groove 72b formed by press molding on the upper surface side of the flange portion 72 in a state of communicating with the longitudinal groove 77a concave and the longitudinal groove 77a. In particular, the outer flange portion 72 is formed. When the radial groove 72b is press-formed, the plate member protrudes in the outer direction, the outer diameter dimension changes, and the positioning in the case of mounting on the inner circumference of the outer tube cannot be performed. A trimming process is required to trim the outer diameter of 72) to the designed dimension in a circular manner, which increases the processing cost.

The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a hydraulic shock absorber which can reduce the processing cost of a rod guide.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional view showing the entire hydraulic shock absorber according to Embodiment 1 of the present invention.

Fig. 2 is an enlarged cross sectional view showing an oil seal and a rod guide portion which are main parts of a hydraulic shock absorber according to Embodiment 1 of the present invention.

Fig. 3 is a plan view showing a rod guide in a hydraulic shock absorber according to Embodiment 1 of the present invention.

4 is a longitudinal sectional view taken along line IV-IV of FIG. 3;

Fig. 5 is an enlarged cross sectional view showing a check lip portion of an oil seal that is a main portion of a hydraulic shock absorber according to the first embodiment of the present invention;

Fig. 6 is a cross sectional view taken along the line VI-VI in Fig. 5;

Fig. 7 is a plan view showing a rod guide in the hydraulic shock absorber according to the second embodiment of the present invention.

8 is a longitudinal sectional view taken along the line VII-VII of FIG.

Fig. 9 is a plan view showing a rod guide in a hydraulic shock absorber according to Embodiment 3 of the present invention.

FIG. 10 is a longitudinal sectional view taken along the line VII-VII of FIG. 9; FIG.

Fig. 11 is an enlarged sectional view of a main portion showing a hydraulic shock absorber according to the prior art;

12 is an enlarged sectional view of a main portion showing a hydraulic shock absorber according to the prior art;

Fig. 13 is an enlarged sectional view of a main portion showing a hydraulic shock absorber according to the prior art;

Fig. 14 is an enlarged sectional view of a main portion showing a hydraulic shock absorber according to the prior art;

Fig. 15 is a plan view showing a rod guide in a conventional hydraulic shock absorber.

* Explanation of symbols for main parts of the drawings

1: cylinder tube 2: piston

4: piston rod 5: outer tube

7: road guide 9: guide bush

11: oil seal (closed member) 11d: check lip

72: flange part (upper flat part) 72a: large diameter part (outer diameter part)

72b: radial groove (radial groove)

72c: small diameter portion 74: rod support portion (guide bush mounting portion)

76: annular horizontal portion (intermediate flat portion) 77: annular upright portion (support cylinder portion)

77a: Long groove (long groove) a: gap

C: Reservoir C: Oil Reservoir

In order to achieve the object as described above, in the hydraulic shock absorber of the present invention, the piston is mounted at both open ends of the cylinder tube in which the piston is slidably received and the outer tube forming a reservoir chamber on the outer circumference thereof, A blocking member including a rod guide equipped with a guide bush for guiding sliding movement, and an oil seal installed at an upper end of the outer tube at an upper portion of the rod guide to seal the piston rod in a sliding manner; The rod guide is formed by press molding of a sheet of sheet material, and has an outer diameter portion inscribed and centered on the inner circumferential surface of the outer tube, an upper flat portion for supporting the closure member, and a vertical suspension in the axial direction from the inside of the upper flat portion. It is formed in the support cylinder part and the lower end of the said support cylinder part, A guide bush mounting portion provided at the lower end of the cylindrical portion formed at the lower end of the cylindrical portion at the intermediate end portion of the cylinder tube and the cylindrical portion which is inscribed in the inner circumferential surface thereof. And an annular recess formed on the upper surface side of the rod guide for forming an oil reservoir between the piston rod outer circumferential surface and the closure member, wherein the closure member is located in the recess toward the recess from the reservoir chamber. A skirt-type check lip is provided in which the tip is in contact with the upper surface side of the intermediate horizontal portion in the rod guide to open the valve only in an outward direction to prevent gas intrusion. Inner circumference of the support cylinder portion to the support cylinder portion of the rod guide that abuts by bending A longitudinal groove portion concave outward from the upper surface portion, and a top groove portion for supporting the closure member is formed with a radial groove portion concave downward from the abutting surface of the closure member and in communication with the longitudinal groove portion. It was formed as a polygon formed with the polygon which has a some large diameter part which contact | connects the inner peripheral surface of the said outer tube, and the some small diameter part which forms the clearance gap between the inner peripheral surface of an outer tube, and the said radial groove part and the longitudinal groove part were formed in the said small diameter part.

Moreover, in the hydraulic shock absorber of Claim 2, the external shape of the said rod guide is formed in the polygon which has an even side, and the means which provided the said radial groove part and the longitudinal groove part in the radial direction target position of the two small diameter parts facing the radial direction, respectively. I did.

In the hydraulic shock absorber according to the first aspect of the present invention, as described above, the outer shape of the rod guide is formed into a polygon having a plurality of large diameter portions that abut against the inner circumferential surface of the outer tube and a plurality of small diameter portions that form a gap between the inner circumferential surface of the outer tube. The radial groove portion and the longitudinal groove portion may be formed in the small diameter portion so that the length of the radial groove may be shortened, thereby reducing the load during press molding and the small diameter portions in which the radial grooves are formed are mounted on the inner circumference of the outer tube. In this case, the trimming step for trimming the outer diameter of the flange portion to the circular shape according to the design dimension is omitted since the portion has no influence on the positioning in the case, and the process cost is reduced accordingly.

Moreover, since the hydraulic shock absorber of Claim 2 is comprised as mentioned above, the grooving for press-molding the radial groove | channel in a press molding part can be performed in the same process, and the target direction can reduce manufacturing cost of a mold member. At the same time, the groove machining accuracy is improved, thereby reducing the frequency of repairing the shape and facilitating the repair.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail by drawing.

1 is a cross-sectional view showing the entire hydraulic shock absorber of Embodiment 1 of the present invention, in which 1 is a cylinder tube, 2 is a piston, 3 is a rebound rubber, 4 is a piston rod, 5 is an outer tube, and 6 is A base, 7 is a rod guide, 11 is an oil seal (closed member), 12 is a packing land cover, A is an upper chamber, B is a lower chamber, and C is a reservoir chamber, respectively.

Next, FIG. 2 is an enlarged cross sectional view showing a part of the rod guide 7, FIG. 3 is a plan view of the rod guide, FIG. 4 is a longitudinal sectional view taken along the line IV-IV of FIG. As described above, the rod guide 7 according to the first embodiment of the present invention is formed by press-forming a sheet of sheet whose outer shape is punched into a substantially square shape, and is formed in a double tubular shape at a lower end thereof. The rod support part (guide bush mounting part) 74 in which the rod through hole 71 which slides 4) in the penetrating state is formed, and the outward flange part (upper planar part) 72 is formed in the upper end. And between this flange part 72 and the rod support part 74, the cylinder coupling part (cylindrical part) 73 is provided, and this cylinder coupling part 73 is inserted in the inner periphery of the cylinder tube 1, and is supported. At the same time, a large diameter portion (outer diameter portion) 72a formed at four corners of the outer circumferential surface of the flange portion 72 is fitted to and supported by the inner circumference of the outer tube 5, and both large diameter portions 72a, adjacent to each other, are supported. 72a) The clearance gap a is formed between each small diameter part 72c and the inner peripheral surface of the outer tube 5, respectively.

In addition, between the cylinder engaging portion 73 and the flange portion 72 is bent outward from the upper end of the cylinder engaging portion 73, as shown in Fig. 5 to enlarge the main portion, the upper end of the cylinder tube (1) A cross-sectional L-shaped annular end portion is formed by an annular horizontal portion (intermediate flat portion) 76 caught on the surface and an annular upright portion (support cylinder portion) 77 from the outer circumference of the annular horizontal portion 76. In addition, radial grooves (radial groove portions) 72b and longitudinal grooves (vertical groove portions) 77a are formed on the inner circumferential surfaces of the annular upright portions 77 at the respective small diameter portion 72c and the small diameter portion 72c. Formed by press molding, the projections 72d and 77d are formed in a continuous rib shape on the lower surface of the radial groove 72b and the outer peripheral surface of the longitudinal groove 77a.

The guide bush 9 is fixedly coupled to the rod through hole (guide bush mounting portion) 71, and a guide seal is provided at the lower side of the guide bush 9 in a state where the omission of the guide bushing 9 is prevented. (8) is installed. The guide seal ring 8 is provided in a substantially close contact with the inner peripheral side of the piston rod 4 with a small gap with respect to the outer peripheral surface of the piston rod, and the hydraulic oil in the upper chamber A moves upward from the rod guide 7 (to be described later). Leakage to the oil storage chamber D direction) is suppressed.

The oil seal 11 is provided above the rod guide 7. The oil seal 11 has a reinforcing ring 11a that is coupled to the inner circumference of the outer tube 5, and the reinforcing ring 11a is in contact with the piston rod 4 on its inner circumferential side. And a rod seal composed of a seal lip 11c, and a skirt-shaped check lip in which the upper surface of the annular horizontal portion 76 of the rod guide 7 is formed as a seal surface on the lower surface side thereof and the lower inner circumferential edge portion thereof is press-contacted. 11d is provided.

Then, the upper end of the outer tube (5) is bent and caulked by the upper side of the oil seal 11, thereby fixing the oil seal 11 and the rod guide 7 in the state of receiving the internal residual axial force It is.

That is, an annular oil reservoir D is formed on the inner circumferential side of the rod guide 7 between the rod guide 7, the piston rod 4, and the oil seal 11 to form a recess of the claim.

Next, the operation of Embodiment 1 of the invention will be described.

(A) At the time of height administration

Since the hydraulic shock absorber of Embodiment 1 of the present invention is configured as described above, in the expansion stroke of the shock absorber, the upper chamber A side is pressurized by the raising of the piston 2 so that a part of the hydraulic oil in the upper chamber A It is fed to the oil storage chamber D side through a minute gap between the piston rod 4 and the rod guide 7, and the oil of the oil seal 11 is lubricated by the hydraulic oil in the oil storage chamber D, The hydraulic fluid in the oil reservoir D opens the check lip 11d as shown by the two-dot chain line in FIG. 5 by the increase in the hydraulic pressure, and the reservoir chamber via the radial groove 72b and the gap a. Reflux into (C).

At this time, if the inner diameter of the annular upright portion 77 is small and the offset amount F between the inner circumferential surface of the annular upright portion 77 and the valve opening center of the check lip 11d is set small, as shown in FIG. As shown by the dashed-dotted line, the outer peripheral edge of the lower end of the check lip 11d may come into contact with the inner circumferential surface of the annular upright portion 77 at the time of valve opening, but in this case as well, A vertical groove 77a is formed in a part of the inner circumferential surface of the annular upright part 77, and the circulation of the hydraulic oil between the oil reservoir D and the radial groove 72d is always secured. At the time of valve opening, the hydraulic oil in the oil storage chamber D can be returned to the reservoir chamber C side via the longitudinal groove 77a and the radial groove 72b. That is, since the inside diameter of the oil storage chamber D in the rod guide 7 can be reduced, the cost can be reduced by the common use of the oil seal 11.

Moreover, since the radial groove 72b in the flange part 72 is formed in the upper surface of the flange part 72 which is the uppermost part of the rod guide 7 which contacts the reinforcement ring 11a of the oil seal 11, it is radial direction Since the working oil is stored in the entire oil reservoir D reaching the level of the bottom of the groove 72b, the entire check lip 11d is always immersed in the working oil during buffer operation, thereby preventing deterioration due to wetting. It is possible to improve the durability due to the cooling action.

(B) during the compression stroke

In the compression stroke of the shock absorber, the upper chamber A side is depressurized by the lowering of the piston 2 while the lower chamber B side is pressurized, and a part of the piston rod 4 is inserted into the cylinder tube 1. By infiltration, the hydraulic oil in the lower chamber B as much as the intrusion volume is refluxed from the base 6 side to the reservoir chamber C side, whereby the gas pressure in the reservoir chamber C rises, thereby increasing the pressure with the reservoir chamber C. The differential pressure is generated between the subsidiary chambers A, but gas leaks from the reservoir chamber C to the oil storage chamber D direction are prevented by the check lip 11d.

As described above, in the hydraulic shock absorber of Embodiment 1 of the present invention, the following effects are obtained.

A radial groove 72b communicating between the oil reservoir D and the reservoir chamber C is provided on the upper surface of the flange portion 72 which is the uppermost part of the rod guide 7 which abuts the reinforcing ring 11a of the oil seal 11. By forming, the entire check lip 11d can be always immersed in the working oil during the operation of the shock absorber, whereby the deterioration due to lubrication and the durability due to the cooling action can be improved.

Even when the check lip 11d contacts the inner circumferential surface of the upright portion 77 in the rod guide 7 at the time of its valve opening, the circulation of the hydraulic oil can be ensured by the longitudinal groove 77a, so that the check lip 11d The inner diameter of the oil storage chamber D in the rod guide 7 can be reduced in size without changing the inner diameter of the rod guide 7, and therefore, the cost of the oil seal 11 can be reduced.

Since the rod guide 7 is easily formed by press molding, the cost can be reduced, and the projections 72d and 77b are continuous on the outer circumference by press molding of the radial groove 72b and the longitudinal groove 77a. By forming the rib shape, the axial strength of the rod guide 7 can be increased.

By forming the outer shape of the rod guide 7 in a substantially square shape, the waste portion can be punched out efficiently from a single sheet of material compared to the circular shape, and thus the material cost can be saved.

By forming the radial groove 72b in each small diameter portion 72c, the length of the radial groove 72b may be shortened as compared with the case where the radial groove 72b is formed in the large diameter portion 72a, thereby reducing the load during press molding. You can do it.

By arranging the radial groove 72b in each small diameter portion 72c having no influence on positioning when mounted on the inner circumference of the outer tube 5, arranging the outer diameter of the flange portion 72 in a circular shape according to design dimensions. Since the trim step can be omitted, the machining cost can be reduced accordingly.

In the rod guide 7 formed in a substantially square shape, the radial grooves 72b are formed in the respective small diameter portions 72c so that each radial groove 72b is formed at the radial target position of the rod guides, respectively. The groove processing for press molding the radial groove 72b in the press-formed shape member can be performed in the same process, so that the manufacturing cost of the mold can be reduced, and the groove machining accuracy is improved, thereby repairing the shape member. It is possible to reduce the frequency and to facilitate maintenance, and to form the steel sheet in the X and Y directions evenly with respect to the roll roll direction, thereby improving the roundness and coaxial accuracy of the outer diameter.

Next, another embodiment of the present invention will be described. In addition, in description of these other invention embodiment, the same code | symbol is attached | subjected to the same component part as the said Embodiment 1, the description is abbreviate | omitted, and only a different point is demonstrated.

As shown in Figs. 7 and 8, the hydraulic shock absorber according to the second embodiment of the present invention is formed by press molding a sheet of steel whose outer shape of the rod guide 7 is punched into a substantially hexagonal shape. The radial grooves (radial groove portions) 72b and the inner peripheral surfaces of the six small diameter portions 72c formed at each of the 72a, 72a and the annular upright portions 77 at the respective small diameter portion 72c positions. The longitudinal groove (vertical groove portion) 77a is formed by press molding.

Therefore, also in the hydraulic shock absorber of Embodiment 2 of this invention, the effect similar to Embodiment 1 of the said invention can be acquired.

As shown in Figs. 9 and 10, the hydraulic shock absorber according to the third embodiment of the present invention is formed by press molding a sheet of punched outer sheet with an approximately pentagonal shape, which is adjacent to each other. Radial grooves (radial groove portions) 72b on the inner circumferential surface of each of the five small diameter portions 72c formed between the neck portions 72a and 72a and the annular upright portion 77 at the respective small diameter portion 72c positions. And the longitudinal groove (vertical groove portion) 77a is formed by press molding.

Therefore, in the hydraulic shock absorber of Embodiment 3 of this invention, since the radial groove 72b is not formed in the radially opposing position, manufacturing cost of a shape member cannot be reduced, but in another point, You can get almost the same effect.

As mentioned above, although this invention was described above with reference to drawings, a specific structure is not limited to embodiment of this invention, Even if there exists a design change in the range which does not deviate from the meaning of this invention, it is included in this invention.

For example, in the embodiment of the invention, the guide bush mounting portion provided at the lower end of the tubular portion at the coupling end and to which the guide bush is mounted is made into a double cylinder, but the guide bush mounting portion is formed in a single cylindrical shape. The present invention can be applied.

As described above, in the hydraulic shock absorber according to the present invention, in order to prevent gas intrusion from the reservoir chamber into the recessed portion in the recessed portion, the front end is in contact with the upper surface side of the intermediate horizontal portion of the rod guide in the recessed portion. The skirt-shaped check lip which opens a valve only is provided, and the longitudinal groove part which is recessed outward from the inner peripheral surface of the said support cylinder part is formed in the support cylinder part of the said rod guide which abuts by the outward bending at the time of valve opening of the check lip. At the same time, the upper planar portion supporting the closure member is formed with a radial groove concave downward from the abutting surface of the closure member and communicating with the longitudinal groove portion, the plurality of the outer shape of the rod guide abuts against the inner peripheral surface of the outer tube. A plurality of gaps are formed between the large diameter portion of the inner tube and the inner circumferential surface of the outer tube. By forming a polygon having a small diameter portion and having the radial groove portion and the longitudinal groove portion formed by the small diameter portion, the length of the radial groove may be shortened, thereby reducing the load during press forming, Since each small diameter part in which the radial groove is formed has no influence on the positioning when mounted on the inner circumference of the outer tube, the trimming process for trimming the outer diameter of the flange part in a circular shape according to the design dimensions can be omitted. The effect that cost can be reduced is acquired.

Moreover, in the hydraulic shock absorber of Claim 2, the outer shape of the said rod guide is formed in the polygon which has an even side, and the said radial groove part and the longitudinal groove part were formed in the radial direction target position of the two small diameter parts facing the radial direction, respectively. Since the grooves for press forming the radial grooves in the press-formed members can be performed in the same process, the target directions can be reduced, and the manufacturing cost of the molds can be reduced, and the groove processing accuracy is improved. It is possible to achieve reduction and facilitating maintenance, and the molding can be formed equally in the X and Y directions with respect to the steel sheet roll direction, so that the roundness and the coaxial precision of the outer diameter can be improved.

Claims (2)

A rod guide mounted at both open ends of the cylinder tube in which the piston is slidably received and at the outer end of the outer tube forming a reservoir chamber at the outer circumference thereof, and at the center thereof with a guide bush for guiding the sliding of the piston rod; A closing member including an oil seal installed at an upper end of the outer tube at an upper part of the rod guide to slidably seal the piston rod, The rod guide is formed by press molding of a sheet, and has an outer diameter portion inscribed and centered on the inner circumferential surface of the outer tube, an upper planar portion for supporting the closure member, and an axially perpendicular from the inside of the upper planar portion. A coupling end formed of a supporting cylinder portion suspended, a intermediate flat portion formed at a lower end of the supporting cylinder portion, and a tubular portion inscribed to an inner circumferential surface of the cylinder tube, and in contact with an inner circumferential surface thereof; It is provided at the bottom and the guide bush mounting portion is equipped with the guide bush, On the upper surface side of the rod guide is formed an annular recess for forming an oil reservoir between the piston rod outer peripheral surface and the closing member, The closure member has a skirt-type check in which the tip is in contact with the upper surface side of the intermediate horizontal portion of the rod guide in order to prevent gas intrusion from the reservoir chamber in the recess in the recess. The lip is installed, A closing member is formed in the upper end portion of the support cylinder of the rod guide, which is in contact with the outer side when the valve is opened by the bending of the check lip, which is concave outward from the inner circumferential surface of the supporting cylinder portion and supports the closure member. A radial groove portion which is concave downward from the abutting surface thereof and communicates with the longitudinal groove portion, The outer shape of the rod guide is formed of a polygon having a plurality of large diameter portion in contact with the inner circumferential surface of the outer tube and a plurality of small diameter portions forming a gap between the inner circumferential surface of the outer tube, wherein the radial groove portion and the longitudinal groove portion are formed in the small diameter portion Hydraulic shock absorber characterized in that. An outer shape of the rod guide is formed in a polygon having an even number of sides, and the radial groove portion and the longitudinal groove portion are formed at radial target positions of both small diameter portions facing the radial direction, respectively. Hydraulic shock absorber.

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