JP2005076722A - Hydraulic draft gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic draft gear capable preventing the sinking of a bump cap into a damper cylinder caused by the enlargement of an opening part of the damper cylinder, even in a case when unexpected excess load is acted on the bump cap fitted to an inner periphery of the opening part of the damper cylinder. <P>SOLUTION: In this hydraulic draft gear 10 wherein a cylindrical mounting part 51 of the bump cap 28 is fitted to the inner periphery of the opening part of the damper cylinder 11, a cylindrical reinforcement ring 60 is fitted to an outer periphery of an opening part of the damper cylinder 11, and a flange part 61 formed by narrowing one end of the reinforcement ring 60 is held between an end face of the opening part of the damper cylinder 11 and a step part 53 at a side of the cylindrical mounting part 51 of the bump cap 28. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hydraulic shock absorber.

  As a hydraulic shock absorber for a motorcycle or the like, as described in Patent Document 1, a piston ring is provided with a stopper ring for locking a shaft seal member in an annular groove provided on the inner periphery near the opening of the damper cylinder. Is inserted through the shaft seal member into the damper cylinder.

In this hydraulic shock absorber, as shown in FIG. 5 (A), a bumper provided on the outer periphery of the piston rod is fitted into the inner periphery of the opening of the damper cylinder with the small outer diameter portion provided in the cylindrical mounting portion of the bump cap. The rubber is abutted against the lid of the bump cap so that the maximum compression stroke can be regulated. In FIG. 5A, 1 is a damper cylinder, 2 is a piston rod, 3 is a shaft seal member, 4 is a stopper ring, 5 is a bump cap, and 6 is a bump rubber.
JP-A-8-93826

  For example, when an adult rides on a children's motorcycle to which the hydraulic shock absorber of Patent Document 1 is applied, the bump cap 5 compressed by the bump rubber 6 is unexpected when the hydraulic shock absorber is at its most compression stroke. Overload may be applied.

  When such an excessive load acts repeatedly, the bump cap 5 is deformed (the central portion of the lid portion of the bump cap 5 is depressed, and the cylindrical mounting portion of the bump cap 5 is expanded in diameter). As a result, as shown in FIGS. 5B and 5C, the cylindrical mounting portion of the bump cap 5 pushes the opening of the damper cylinder 1 starting from the annular groove for the stopper ring 4 in the damper cylinder 1. It is conceivable that the bump cap 5 is recessed into the damper cylinder 1. In the worst case, the cylindrical mounting portion of the bump cap 5 may abut against the stopper ring 4 and the stopper ring 4 may be detached.

  In order to prevent such deformation of the bump cap 5, the thickness of the bump cap 5 is increased, the inner peripheral chamfer of the end surface of the opening of the damper cylinder 1 is decreased, or the annular groove for the stopper ring 4 is formed. Although measures such as reducing the depth of the surface are conceivable, there is a possibility that deformation due to an unexpected excessive load cannot be prevented with these measures alone.

  The subject of the present invention is that in the hydraulic shock absorber, even when an unexpected excessive load is applied to the bump cap fitted to the inner periphery of the opening of the damper cylinder, the opening of the damper cylinder expands. The bump cap is prevented from being recessed into the damper cylinder.

  According to the first aspect of the present invention, a stopper ring for locking the shaft sealing member is engaged with an annular groove provided on the inner periphery near the opening of the damper cylinder, and the piston rod is passed through the shaft sealing member to provide a damper cylinder. The small outer diameter part of the bump cap's cylindrical mounting part is fitted to the inner periphery of the opening of the damper cylinder, and the bump rubber provided on the outer periphery of the piston rod is brought into contact with the lid part of the bump cap. In the hydraulic shock absorber that can regulate the maximum compression stroke, a flange that is fitted with a cylindrical reinforcing ring on the outer periphery of the opening of the damper cylinder and that is capped with one end of the reinforcing ring is the opening of the damper cylinder. It is configured to be sandwiched between the end face of the portion and the step portion on the side of the small outer diameter portion provided in the cylindrical mounting portion of the bump cap.

  According to a second aspect of the present invention, in the first aspect of the present invention, the reinforcing ring is fitted to a position corresponding to an annular groove on the inner periphery of the damper cylinder that is provided on the inner periphery of the damper cylinder in the axial direction of the damper cylinder. It is designed to be worn.

(Claim 1)
a Cylindrical reinforcing ring fitted on the outer periphery of the opening of the damper cylinder prevents the diameter of the opening of the damper cylinder from expanding. Therefore, even if the bump rubber applies an unexpected excessive load to the bump cap fitted to the inner periphery of the damper cylinder opening during the most compression stroke of the hydraulic shock absorber, the bump cap stays in the damper cylinder. Prevent encroachment.

  b The flange of the reinforcing ring is sandwiched between the end face of the opening of the damper cylinder and the step portion on the side of the small outer diameter portion of the cylindrical mounting portion of the bump cap, so that the reinforcing ring is attached to the damper cylinder. It can be easily attached to the outer periphery of the opening.

(Claim 2)
c By fitting the reinforcing ring up to the position corresponding to the annular groove for engaging the stopper ring on the inner periphery of the damper cylinder, it is possible to reliably prevent the opening of the damper cylinder from expanding from the annular groove as a starting point.

  1 is a sectional view showing a hydraulic shock absorber, FIG. 2 is an enlarged view of the main part of FIG. 1, FIG. 3 is a half sectional view showing a bump cap, FIG. 4 is a half sectional view showing a reinforcing ring, and FIG. It is a schematic diagram which shows the deformation | transformation state of the opening part of the damper cylinder.

  As shown in FIG. 1, the hydraulic shock absorber 10 includes a piston rod 12 inserted into a damper cylinder 11 and a suspension spring 13 interposed between the damper cylinder 11 and the piston rod 12. The damper cylinder 11 includes a vehicle body side mounting portion 14, and the piston rod 12 includes a wheel side mounting portion 15.

  In the hydraulic shock absorber 10, a spring receiver 16 is fixed to the outer periphery of the damper cylinder 11, a spring receiver 17 is fixed to the piston rod 12, and a suspension spring 13 is interposed between the spring receiver 16 and the spring receiver 17. The elastic force of the suspension spring 13 absorbs the impact force that the vehicle receives from the road surface.

  As shown in FIG. 2, the hydraulic shock absorber 10 is provided with a shaft seal member (rod guide) 21 through which the piston rod 12 penetrates on the inner periphery of the damper cylinder 11, and an annular shape provided on the inner periphery near the opening of the damper cylinder 11. The shaft seal member 21 is locked by a stopper ring 23 engaged with the groove 22 so as to be prevented from coming off. The shaft seal member 21 is liquid-tightly fitted to the damper cylinder 11 via an O-ring 24, and the piston rod 12 is slidable in a liquid-tight manner in an inner diameter portion including an oil seal 25, a bush 26 and a dust seal 27. Through. The oil seal 25 is held by the seal retainers 25A and 25B and is loaded in the inner concave portion of the shaft seal member 21. In the dust seal 27, the base end portion 27A is press-fitted into the shaft seal member 21, and the seal lip 27B is backed up by a spring 27C and is brought into sliding contact with the piston rod 12.

  The hydraulic shock absorber 10 has a covered cylindrical bump cap 28 fixedly attached to the opening of the damper cylinder 11. A lid 52 (to be described later) of the bump cap 28 passes through the piston rod 12, directly faces the outer periphery of the piston rod 12 outside the seal lip 27 </ b> B of the dust seal 27, and is a damper in a state through a small gap from the outer periphery of the piston rod 12. The opening of the cylinder 11 is closed. The flat surface outside the lid portion 52 of the bump cap 28 becomes an abutting surface of the bump rubber 29 provided at the outer end of the piston rod 12 at the time of maximum compression, and regulates the maximum compression stroke.

  The hydraulic shock absorber 10 includes a rebound rubber 31 in a recess on the inner end surface of the shaft seal member 21, and at the time of extension, the rebound stopper 32 provided near the inner end of the piston rod 12 is abutted against the rebound rubber 31 and extended. Regulate the stroke.

  The hydraulic shock absorber 10 has a rebound stopper / valve stopper 32, a pressure side valve 33, a piston 34, an extension side valve 35, and a valve stopper 36 inserted into the inner end of the piston rod 12 inserted into the damper cylinder 11. 37 is fixed.

  The piston 34 is in fluid-tight sliding contact with the inside of the damper cylinder 11 via an O-ring 38A and a piston ring 38B provided on the outer periphery, and the rod-side chamber 39A in which the piston rod 12 is accommodated in the damper cylinder 11 and the piston rod 12 A piston-side chamber 39B that is not accommodated is defined. The piston 34 includes a pressure side valve 33 and a pressure side flow path 33A (not shown) that allows the rod side chamber 39A and the piston side chamber 39B to communicate with each other. The piston 34 includes an expansion side valve 35 that allows the rod side chamber 39A and the piston side chamber 39B to communicate with each other. The extending side channel 35A is provided.

  The hydraulic shock absorber 10 is provided with a free piston 41 slidably in a liquid-tight manner inside the damper cylinder 11, and the free piston 41 divides the piston side chamber 39 </ b> B and the pressurized gas chamber 39 </ b> C. A stopper 42 that restricts the sliding end of the free piston 41 is caulked and fixed inside the damper cylinder 11.

  When the hydraulic shock absorber 10 is compressed, the oil in the piston side chamber 39B passes through the pressure side flow path 33A, opens the pressure side valve 33 and is guided to the rod side chamber 39A, and generates a pressure side damping force.

  When the hydraulic shock absorber 10 is extended, the oil in the rod side chamber 39A passes through the extension side flow path 35A, opens the extension side valve 35 and is guided to the piston side chamber 39B, and generates an extension side damping force.

  The oil corresponding to the entry volume of the piston rod 12 entering the damper cylinder 11 when the hydraulic shock absorber 10 is compressed and the oil corresponding to the withdrawal volume of the piston rod 12 retracting from the damper cylinder 11 when extended are added by the displacement of the free piston 41. Absorbed by expansion / contraction of the pressurized gas chamber 39C.

  However, in the hydraulic shock absorber 10, even when an unexpected excessive load is applied to the bump cap 28 with which the bump rubber 29 abuts at the time of the maximum compression, the opening of the damper cylinder 11 expands to increase the bump cap 28. Has the following configuration in order to prevent it from sinking into the damper cylinder 11.

  As shown in FIGS. 2 and 3, the bump cap 28 has a cylindrical shape with a lid, and includes a thin cylindrical mounting portion 51 and a thick lid portion 52. The bump cap 28 has a small outer diameter portion 51 </ b> A provided in the cylindrical mounting portion 51 fitted and fixed to the inner periphery of the cylindrical opening of the damper cylinder 11 by press fitting, and a flat surface 52 </ b> A provided in the lid portion 52 has a bump rubber 29. It will be the contact area for The bump cap 28 is located on the side of the small outer diameter portion 51 </ b> A of the cylindrical mounting portion 51, and a portion where the base end portion of the lid portion 52 is in contact with the axially perpendicular end surface of the opening portion of the damper cylinder 11. It is provided as a stepped portion 53 having a stepped surface.

  A cylindrical reinforcing ring 60 is fitted on the outer periphery of the opening of the damper cylinder 11. As shown in FIGS. 2 and 4, the reinforcing ring 60 has a flange portion 61 having one end capped. When the small outer diameter portion 51 </ b> A included in the cylindrical mounting portion 51 of the bump cap 28 is fitted and fixed to the inner periphery of the opening portion of the damper cylinder 11, the flange portion 61 of the reinforcing ring 60 is connected to the end surface of the opening portion of the damper cylinder 11. And the stepped portion 53 on the side of the small outer diameter portion 51A of the bump cap 28. The reinforcing ring 60 can be easily attached without being press-fitted into the outer periphery of the opening of the damper cylinder 11.

  The reinforcing ring 60 is fitted to a position corresponding to or beyond the annular groove 22 for the stopper ring 23 provided on the inner periphery of the damper cylinder 11 in the axial direction of the damper cylinder 11.

According to the present embodiment, the following operational effects can be obtained.
a The cylindrical reinforcing ring 60 fitted on the outer periphery of the opening of the damper cylinder 11 prevents the diameter of the opening of the damper cylinder 11 from expanding. Therefore, even when the bump rubber 29 acts on the bump cap 28 fitted to the inner periphery of the opening of the damper cylinder 11 during the maximum compression stroke of the hydraulic shock absorber 10, the bump cap 28 Is prevented from sinking into the damper cylinder 11.

  b By sandwiching the flange portion 61 of the reinforcing ring 60 between the end surface of the opening of the damper cylinder 11 and the step portion 53 on the side of the small outer diameter portion 51 </ b> A included in the cylindrical mounting portion 51 of the bump cap 28. The reinforcing ring 60 can be easily attached to the outer periphery of the opening of the damper cylinder 11.

  c By fitting the reinforcing ring 60 to a position corresponding to the annular groove 22 engaged with the stopper ring 23 on the inner periphery of the damper cylinder 11, the opening of the damper cylinder 11 expands from the annular groove 22 as a starting point. Can be reliably prevented.

  The embodiment of the present invention has been described with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention, Included in the invention.

FIG. 1 is a sectional view showing a hydraulic shock absorber. FIG. 2 is an enlarged view of a main part of FIG. FIG. 3 is a half sectional view showing the bump cap. FIG. 4 is a half sectional view showing the reinforcing ring. FIG. 5 is a schematic diagram showing a conventional example and a deformed state of the opening of the damper cylinder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hydraulic shock absorber 11 Damper cylinder 12 Piston rod 21 Shaft seal member 22 Annular groove 23 Stopper ring 28 Bump cap 29 Bump rubber 51 Cylindrical attachment part 51A Small outer diameter part 52 Lid part 53 Step part 60 Reinforcement ring 61 A collar part

Claims (2)

A stopper ring for locking the shaft seal member is engaged with an annular groove provided on the inner circumference near the opening of the damper cylinder, and the piston rod is inserted into the damper cylinder through the shaft seal member.
Fit the small outer diameter part of the bump cap's cylindrical mounting part to the inner periphery of the opening of the damper cylinder, and hit the bump rubber provided on the outer periphery of the piston rod against the cover part of the bump cap. In the hydraulic shock absorber that can regulate
A cylindrical reinforcing ring is fitted on the outer periphery of the damper cylinder opening, and a flange portion with one end of the reinforcing ring is provided on the end surface of the damper cylinder opening and the cylindrical mounting portion of the bump cap. The hydraulic shock absorber is sandwiched between a step portion on the side of the portion. 2. The hydraulic shock absorber according to claim 1, wherein the reinforcing ring is fitted to a position corresponding to an annular groove for engaging a stopper ring provided on an inner periphery of the damper cylinder in an axial direction of the damper cylinder.

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