JP2006242270A - Hydraulic shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic shock absorber provided with a structure capable of preventing unpleasant noise caused by a rebound member from being generated in operation of suspension. <P>SOLUTION: This hydraulic shock absorber is provided with: a full stretch restriction member 6 mounted to a cylinder 3; a stopper member 7 attached to a piston rod 5; and the rebound member 8 interlaid between the full stretch restriction member and the stopper member for relaxing shock in full stretch; and is so structured that the rebound member is composed of a coil spring 22 and a holder 24; and contacting parts 31 and 20 for bringing the holder and the stopper member into surface contact with each other in bringing the rebound member into contact with the stopper member are formed on the holder and the stopper member, respectively. In the hydraulic shock absorber, a connection recessed part 5a is formed on one side of the holder and the piston rod; a connection projecting part 24b connected to the connection recessed part is formed on the other side thereof; and the holder and the piston rod are positioned and fixed by connecting the connection projecting part to the connection recessed part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydraulic shock absorber provided with a rebound member for alleviating an impact when a piston rod is fully extended.

  Conventionally, as a hydraulic shock absorber provided with a rebound member that alleviates an impact when the piston rod is fully extended, the one shown in Patent Document 1 can be exemplified.

  This hydraulic shock absorber is sealed between a rod guide as an extension regulating member that seals the cylinder opening end and pivotally supports the piston rod, and a flange member as a stopper member provided on the base end side of the piston rod. The rebound member which consists of a coil spring with which the holder was fitted by the both ends is interposed.

In this hydraulic shock absorber, when the piston rod is fully extended, the rebound member is compressed with the coil spring compressed in a state where the holders at both ends thereof are in contact with the rod guide and the flange member. It is designed to reduce the impact when cutting.
Japanese Patent Laid-Open No. 2004-84776 (FIG. 4)

  The hydraulic shock absorber configured as described above is not particularly problematic, but the following problems may occur.

  That is, since the rebound member is not particularly positioned and fixed with respect to the piston rod, the rebound member may move relative to the piston rod depending on the operating state of the suspension.

  In this case, as shown in FIG. 4, the flange-side contact portion 52 of the flange member 51 and the holder-side contact portion 54 of the holder 53 are formed in a planar shape, and the contact portions 52 and 54 are in close contact with each other. In such a state, if the surface touches vigorously during the relative movement described above, a loud contact sound is generated, and this sound may be heard as an unpleasant noise by the passenger.

  Therefore, the present invention was devised to solve the above-described problems, and the object thereof is to provide a structure in which unpleasant noise caused by the rebound member does not occur during operation of the suspension. It is to provide a hydraulic shock absorber.

  In order to achieve the above object, the present invention includes a cylinder, an extension restriction member provided in the cylinder, a piston rod movably inserted into the cylinder via a piston, and a stopper member provided in the piston rod. And a rebound member that is interposed between the extension limit regulating member and the stopper member to relieve an impact at the time of extension, and the rebound member is inserted into a coil spring and at least a stopper member side of the coil spring. The holder and the stopper member are each provided with an abutting portion for bringing the holder and the stopper member into surface contact with each other when the rebound member abuts against the stopper member. If a coupling recess is provided in one of the holder or the piston rod, And the other to provide a coupling protrusion that binds to the binding recess, is characterized in that the positioning securing the holder and the piston rod by fitting the coupling protrusion with these coupling recess.

  According to the present invention, the holder and the piston rod are coupled to each other by the coupling concave portion and the coupling convex portion provided on the holder and the piston rod. The member and the piston rod are positioned and fixed.

  Accordingly, since the rebound member can be prevented from moving relative to the piston rod in the suspension operating state as shown in the conventional example, it is possible to reliably prevent the generation of a loud contact sound caused by this relative movement. Can do.

  Hereinafter, an embodiment in which the present invention is embodied in a double cylinder type hydraulic shock absorber used in a suspension device for an automobile will be described with reference to the drawings.

  As shown in FIG. 1, the hydraulic shock absorber 1 includes an inner cylinder 3 as a cylinder inserted into the outer cylinder 2, and a piston rod 5 inserted into the inner cylinder 3 through a piston 4 so as to be freely retractable. , A rod guide 6 serving as an extension regulating member that seals the end of the inner cylinder 3 and pivotally supports the piston rod 5, a stopper member 7 provided on the proximal end side of the piston rod 5, and the stopper member 7 and the rod guide 6 And a rebound member 8 interposed therebetween.

  Hereinafter, in detail, the outer cylinder 2 and the inner cylinder 3 are arranged concentrically, the rod guide 6 is fitted and folded over the inner periphery of the end of the outer cylinder 2 and the end of the inner cylinder 3, This rod guide 6 is provided with a guide hole 11 for guiding the piston rod 5 in the center thereof, and the piston rod 5 is slidably supported via an annular bearing member 12 fitted in the guide hole 11. Yes.

  A seal member 13 for sealing a gap with the piston rod 5 is disposed on the upper surface of the rod guide 6, and the rod guide 6 and the seal member 13 are attached to the outer cylinder by bending the end of the outer cylinder 2 inward and crimping. 2 and the inner cylinder 3 are fixed.

  The piston 4 is inserted into the proximal end portion of the piston rod 5 and fixed by a nut 15, and the inner cylinder 3 is partitioned into a rod chamber R and a piston chamber P by the piston 4.

  Further, a pressure side valve 16 is provided on the side surface of the rod chamber R of the piston 4 so as to open and close a pressure side port (not shown), and an extension side that closes the expansion side port 17 on the side of the piston chamber P of the piston 4 is openable. A side valve 18 is provided.

  The stopper member 7 is made of metal, and includes a cylindrical fixing portion 19 and a disk-shaped flange portion 21 connected to the upper portion of the fixing portion 19. Is provided with a flat flange-side contact portion 20 so that a holder-side contact portion 31 of a rebound member 8 described later is placed in a surface contact state.

  The stopper member 7 is inserted into the piston rod 5 and the fixed portion 19 is contracted with respect to the reduced diameter mounting portion 9 provided immediately above the piston 4 which is the base end side of the piston rod 5. It is fixed by caulking in the radial direction.

  As shown in FIG. 2, a coupling groove 5a as a coupling recess having a frustoconical cross section is formed over the entire circumference immediately above the stopper member 7 in the piston rod 5, and is provided in a lower holder 24 described later. The protrusion 24b is fitted.

  The rebound member 8 includes a coil spring 22 and synthetic resin upper and lower holders 23 and 24 fitted to both ends thereof. The upper and lower holders 23 and 24 are respectively provided with upper and lower holders 23 and 24. Insertion holes 23 a and 24 a for inserting the piston rod 5 are provided.

  The lower holder 24 is provided with a thick cylindrical lower main body portion 25 and a fitting portion 26 that is suspended from the lower main body portion 25 and has an outer diameter smaller than that of the lower main body portion 25. A guide portion 27 for guiding the coil spring 22 provided above the portion 26, and on the lower surface of the lower body portion 25, the same flat holder side that contacts the flange-side contact portion 20 of the stopper member 7. A contact portion 31 is provided.

  Further, as shown in FIG. 3, the inner peripheral surface constituting the insertion hole 24a of the lower holder 24 has a projection 24b as a coupling convex portion having substantially the same cross-sectional shape as the coupling groove 5a projecting inward. Three pieces (only two are shown in FIGS. 1 and 3) are formed integrally with the holder 24 at a predetermined interval, and are fitted into the coupling groove 5 a of the piston rod 5. .

  Accordingly, when the protrusion 24b of the lower holder 24 is fitted into the coupling groove 5a, the rebound member 8 is in a state where the holder side contact portion 31 of the lower holder 24 is in contact with the flange side contact portion 20 of the stopper member 7. Is positioned and fixed to the piston rod 5.

  The upper holder 23 includes a cylindrical holder main body 28, a fitting portion 29 having an outer diameter smaller than that of the holder main body 28, and a tapered portion 30 extending from the fitting portion 29. The upper end portion of the coil spring 22 is guided by the taper portion 30 and is fitted into the fitting portion 29.

  In the hydraulic shock absorber 1 configured as described above, when the protrusion 24b of the lower holder 24 is fitted in the coupling groove 5a of the piston rod 5, as shown in FIG. 31 comes into contact with the flange-side contact portion 20 of the stopper member 7, and the rebound member 8 and the piston rod 5 are positioned and fixed.

  Accordingly, since the rebound member 8 can be reliably prevented from moving relative to the piston rod 5 in the operating state of the suspension as shown in the conventional example, that is, it can be reliably prevented from moving alone, a large contact noise caused by this movement can be prevented. Can be reliably prevented.

  Since the piston groove 5 is provided with the coupling groove 5a serving as the coupling concave portion of the present invention, an extra convex portion can be formed on the outer peripheral surface of the piston rod 5 as compared with the piston rod 5 having the coupling convex portion of the present invention. Accordingly, the stopper member 7 can be inserted into the piston rod 5 and the rebound member 8 can be easily inserted.

  The present invention is not limited to the above-described embodiments, and can be embodied with the following modifications, for example.

1) In the present embodiment, the plurality of protrusions 24b are used as the coupling protrusions. However, the present invention is not limited to this, and for example, a protrusion formed on the entire inner peripheral surface of the lower holder 24 may be used. .
2) In the present embodiment, the coupling groove 5a provided on the entire circumference of the piston rod 5 is used as the coupling recess. However, the present invention is not limited to this, and a partial groove portion to be fitted to the protrusion 24b is used as the piston. The connecting recess may be provided on the outer peripheral surface of the rod 5.

  3) In the present embodiment, the coupling groove 5a as the coupling concave portion is provided in the piston rod 5 and the projection 24a as the coupling convex portion is provided in the lower holder 24. However, the present invention is not limited to this. The coupling groove 5 a may be provided in the lower holder 24, and the projection 24 b as a coupling convex portion may be provided in the piston rod 5.

  4) In the present embodiment, the invention is embodied in the double cylinder type hydraulic shock absorber 1, but may be embodied in a single cylinder type hydraulic shock absorber.

It is a partially broken front view of a hydraulic shock absorber showing an embodiment of the present invention. It is a partial expanded sectional view which shows the coupling groove part of a piston rod. It is a partial expanded sectional view which shows the protrusion part of a lower holder. It is a partially broken front view which shows the prior art example of this invention.

Explanation of symbols

3 Inner cylinder (cylinder)
4 Piston 5 Piston rod 5a Coupling groove 6 Rod guide (extending member)
7 Stopper member 8 Rebound member 20 Flange side contact part (contact part)
22 Coil spring 24 Lower holder (holder)
24a Insertion hole 24b Protrusion (joint convex part)

Claims (3)

A cylinder, an expansion limit regulating member provided on the cylinder, a piston rod movably inserted into the cylinder via a piston, a stopper member provided on the piston rod, and between the extension limit regulating member and the stopper member And a rebound member that relieves an impact at the time of extension, and includes a coil spring and a holder inserted into the piston rod through an insertion hole on at least the stopper member side of the coil spring. And a hydraulic shock absorber in which a contact portion for bringing the holder and the stopper member into surface contact with each other at the time of contact of the rebound member with the stopper member is provided in each of the holder and the stopper member. A coupling recess is provided on one side and coupled to this coupling recess on the other The Department provided a hydraulic shock absorber, characterized in that the positioning and fixing the holder and the piston rod by coupling the coupling protrusion with these coupling recess. 2. The coupling recess and the coupling projection are provided on the holder or the piston rod so that the holder and the stopper member are positioned and fixed in a state where the contact portions of the holder and the stopper member are in surface contact with each other. Hydraulic shock absorber. The hydraulic shock absorber according to claim 1 or 2, wherein the coupling concave portion is an annular groove, and the coupling convex portion is a plurality of protrusions fitted in the annular groove.

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