JP2008069855A - Rebound spring structure of hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent cracking of a collar while securely press-fitting a rebound spring into a cylindrical portion of a collar in a rebound spring structure of a hydraulic shock absorber.
In a rebound spring structure of a hydraulic shock absorber, a resin collar 50 having a cylindrical portion 51 for restraining the inner diameter of a rebound spring 70 and a flange portion 52 for receiving an end portion of the rebound spring is used. A groove 101 </ b> A along the axial direction is provided at least at a single position in the circumferential direction of the outer periphery of 50 cylindrical portions 51.
[Selection] Figure 3

Description

  The present invention relates to a rebound spring structure for a hydraulic shock absorber.

  In the hydraulic shock absorber, as described in Patent Document 1, a rebound spring is interposed between a resin collar provided on the piston side of the piston rod and a resin collar provided on the rod guide side of the piston rod, The maximum stroke is regulated by compressing the rebound spring when the piston rod is extended.

The collar is made of resin as described above, and prevents the contact between the rebound spring and the piston rod and the hitting sound. The collar includes a cylindrical portion that restrains the inner diameter of the rebound spring and a flange portion that receives the end of the rebound spring. The inner diameter of the rebound spring is press-fitted and fixed to the outer periphery of the cylindrical portion, The part is seated on the upper surface of the flange part.
JP2004-60827

  The tightening allowance for press-fitting the rebound spring to the tubular portion of the collar cannot be made too small in order to prevent the rebound spring from coming off, and a certain tightening allowance is required. On the other hand, since the collar is a resin molded body and has a large dimensional tolerance, the allowance for press-fitting the rebound spring to the cylindrical portion of the collar may be excessive. Excessive press-fitting allowance causes deformation of the collar to increase the stress generated in the collar, which in turn causes the collar to crack.

  An object of the present invention is to prevent a collar from cracking in a rebound spring structure of a hydraulic shock absorber while reliably pressing a rebound spring into a cylindrical portion of the collar.

  According to a first aspect of the present invention, in the rebound spring structure in which a collar is loaded on the end portion of the rebound spring of the hydraulic shock absorber, a tubular portion that restrains the inner diameter of the rebound spring and a flange portion that receives the end portion of the rebound spring are provided. A resin collar is used, and a groove along the axial direction is provided at least at a single position in the circumferential direction of the inner periphery or outer periphery of the cylindrical portion of the collar.

  According to a second aspect of the present invention, in the first aspect of the present invention, a groove along the radial direction is provided at least at a single position in the circumferential direction of the upper surface or the lower surface of the flange portion of the collar.

  A third aspect of the invention is a collar used in the rebound spring structure of the hydraulic shock absorber according to the first or second aspect.

(Claim 1)
(a) When the rebound spring is surely press-fitted into the cylindrical part of the collar, even if the tightening allowance for press-fitting to the cylindrical part of the collar becomes excessive, the deformation that occurs in the collar due to this tightness Absorption due to the presence of grooves provided on the outer periphery (or inner periphery) of the cylindrical portion, as a result, the stress generated in the collar is not increased, and the crack of the collar can be prevented.

(Claim 2)
(b) By providing a groove on the upper surface (or lower surface) of the flange portion of the collar, even when the deformation that occurs in the collar due to the press-fit allowance to the tubular portion of the collar is large, this deformation is tubular. In addition to the presence of the groove provided on the outer periphery (or inner periphery) of the portion, it is also absorbed by the presence of the groove on the upper surface (or the lower surface) of the flange portion. Breaking can be prevented.

(Claim 3)
(c) According to the above (a) and (b), it is possible to provide a collar that is loaded into the end portion of the rebound spring and that can securely press-fit the rebound spring and that does not crack.

  1 is an overall half sectional view showing a hydraulic shock absorber, FIG. 2 is a sectional view showing a rebound spring structure of Example 1, FIG. 3 shows A part and B part of FIG. 2, and (A) is an enlarged view of the lower collar side. FIG. 4B is an enlarged view of the upper collar side, FIG. 4 is a perspective view showing the collar, FIG. 5 is a perspective view showing a modified example of the collar, FIG. 6 shows the main part of the rebound spring structure of Example 2, A) is an enlarged view of the lower collar side, (B) is an enlarged view of the upper collar side, and FIG. 7 is a perspective view showing the collar.

Example 1 (FIGS. 1 to 5)
FIG. 1 shows a double cylinder type hydraulic shock absorber 10, which comprises a double tube with a cylinder 12 built in a damper tube 11, a piston rod 13 is inserted into the cylinder 12, and a fixed attachment is made to the upper end of the piston rod 13. A bracket (not shown) is connected to the vehicle body side, and an eye joint 14 welded to the outer surface of the bottom portion 11A of the damper tube 11 is connected to the wheel side to constitute a vehicle suspension system.

  The hydraulic shock absorber 10 has a suspension spring 16 interposed between a lower spring seat 15 on the outer periphery of the damper tube 11 and an upper spring seat (not shown) supported by a mounting bracket at the upper end portion of the piston rod 13.

  The hydraulic shock absorber 10 sandwiches a rod guide 17, a bush 18, and an oil seal 19 for the piston rod 13 inserted into the cylinder 12 between the upper crimping portion 20 of the damper tube 11 and the upper end portion of the cylinder 12. It is fixed.

  The hydraulic shock absorber 10 has a piston valve device 30 and a bottom valve device 40, and controls the expansion and contraction vibration of the piston rod 13 accompanying the absorption of the impact force by the suspension spring 16 by the damping force generated by them.

(Piston valve device 30)
In the piston valve device 30, a valve stopper 31, a check valve 32, a piston 33, a disk valve 34, and a valve stopper 35 are attached to the piston rod 13, and these are fixed by nuts 36.

  At the time of compression, the oil in the piston-side oil chamber 37A passes through the pressure-side flow path 38A of the piston 33, bends and deforms the check valve 32, and is guided to the rod-side oil chamber 37B. Further, at the time of extension, the oil in the rod side oil chamber 37B passes through the extension side flow path 38B (not shown) of the piston 33, bends and opens the disk valve 34, is guided to the piston side oil chamber 37A, and is extended to the extension side. Generate a damping force.

(Bottom valve device 40)
In the hydraulic shock absorber 10, a gap between the damper tube 11 and the cylinder 12 serves as a reservoir chamber 41, and the interior of the reservoir chamber 41 is partitioned into an oil chamber and a gas chamber. The bottom valve device 40 closes the bottom 11A of the damper tube 11 by spinning molding, and arranges a bottom piece 43 that partitions the piston-side oil chamber 37A and the reservoir chamber 41 inside the cylinder 12 at the lower end of the cylinder 12, The piston-side oil chamber 37 </ b> A and the reservoir chamber 41 can be communicated with each other through a flow path (not shown) provided in the bottom piece 43. Bolts 44 and nuts 45 are fastened to the bottom piece 43, and a disc valve 46, a bottom piece 43, a check valve 47 and a valve stopper 48 are interposed between the bolts 44 and the nut 45.

  At the time of compression, the oil corresponding to the volume of the piston rod 13 entering the cylinder 12 opens from the piston-side oil chamber 37A through the pressure-side flow path 49A of the bottom piece 43 by bending the disk valve 46, thereby opening the reservoir chamber. 41 to obtain a compression side damping force. At the time of extension, the oil corresponding to the retraction volume of the piston rod 13 retreating from the cylinder 12 pushes the check valve 47 open, and from the reservoir chamber 41 via the expansion side flow path 49B (not shown) of the bottom piece 43, the piston side oil chamber 37A. Will be replenished.

  However, as shown in FIGS. 2 and 3, the hydraulic shock absorber 10 has a first collar 50 fixed to the piston 33 side (lower side) around the piston rod 13 positioned in the rod side oil chamber 37 </ b> B of the cylinder 12. And a second collar 60 loosely inserted on the rod guide 17 side (upper side) via a rebound spring 70 that is compressed and deformed when the piston rod 13 is extended (the maximum extension state of the hydraulic shock absorber 10). Disguise.

  The first collar 50 is backed up by a rebound sheet 21 that is caulked and fixed in the groove of the piston rod 13, and is loaded on the lower end of the rebound spring 70.

  The first collar 50 is made of a resin such as nylon resin, and includes a cylindrical portion 51 that restrains the inner diameter of the rebound spring 70 and a flange portion 52 that receives a lower end portion of the rebound spring 70. The outer periphery of the cylindrical portion 51 forms a spring inner diameter restraining surface 51A that is press-fitted into the inner diameter of the rebound spring 70 and is fitted and fixed. The flange portion 52 includes a spring seat surface 52 </ b> A that receives a flat seat surface 71 ground on the end surface of the lower end portion of the rebound spring 70. The first collar 50 includes a relief groove 53 along the entire circumference of the corner portion where the spring inner diameter restraint surface 51A of the cylindrical portion 51 and the spring sheet surface 52A of the flange portion 52 intersect. The escape groove 53 may be provided only on the spring seat surface 52A, or may be provided across the spring inner diameter restraint surface 51A to the spring seat surface 52A.

  The flange portion 52 of the first collar 50 has a convex shape or a notch groove shape along the radial direction at a plurality of circumferential positions on the outer end surface (lower surface) opposite to the spring seat surface 52 </ b> A that receives the lower end seating surface 71 of the rebound spring 70. The oil path formation part 52B is provided. A first oil passage 54 is formed between the outer end surface of the flange portion 52 of the first collar 50 and the rebound sheet 21 in a state where the outer end surface of the flange portion 52 abuts on the upper end surface of the rebound sheet 21 of the piston rod 13.

  The first collar 50 includes protrusions 55 that engage with the piston rod 13 at a plurality of positions in the circumferential direction on the inner periphery. The first collar 50 is assembled to the piston rod 13 in a semi-fixed state by press-fitting the protrusion 55 into the piston rod 13. On the inner periphery of the first collar 50, a portion sandwiched between adjacent protrusions 55 forms a substantially annular gap with the outer periphery of the piston rod 13.

  The second collar 60 is made of a resin such as nylon resin, and includes a cylindrical portion 61 that restrains the inner diameter of the rebound spring 70 and a flange portion 62 that receives the upper end portion of the rebound spring 70. The outer periphery of the cylindrical portion 61 forms a spring inner diameter restraining surface 61A that is press-fitted into the inner diameter of the rebound spring 70 and is fitted and fixed. The flange portion 62 includes a spring seat surface 62 </ b> A that receives a flat seat surface 72 ground on the end surface of the upper end portion of the rebound spring 70. The second collar 60 includes a relief groove 63 along the entire circumference of the corner portion where the spring inner diameter restraining surface 61A of the tubular portion 61 and the spring seat surface 62A of the flange portion 62 intersect. Similarly to the escape groove 53 of the first collar 50, the escape groove 63 may be provided only on the spring seat surface 62A, or may be provided across the spring inner diameter restraint surface 61A to the spring seat surface 62A.

  The flange portion 62 of the second collar 60 has a convex shape or a notch groove shape along the radial direction at a plurality of circumferential positions on the outer end surface (upper surface) opposite to the spring seat surface 62 </ b> A that receives the upper end seating surface 72 of the rebound spring 70. The oil path formation part 62B is provided. A second oil passage 64 (not shown) is provided between the outer end surface of the flange portion 62 of the second collar 60 and the rod guide 17 in a state where the outer end surface of the flange portion 62 abuts with the lower end surface of the rod guide 17 when the piston rod 13 is extended. Form.

  An annular gap is formed between the inner periphery of the second collar 60 and the outer periphery of the piston rod 13 and slides along the piston rod 13.

  When the first collar 50 and the second collar 60 are abutted with each other (in this embodiment, when the upper end surface of the tubular portion 51 and the lower end surface of the tubular portion 61 are abutted), the flange portion 52 of the first collar 50 is used. The interval between the spring seat surface 52A of the second collar 60 and the spring seat surface 62A of the second collar 60 is longer than the most compressed length (contact length) of the rebound spring 70.

  When the piston rod 13 expands and contracts during normal operation of the hydraulic shock absorber 10, the second collar 60 is in a range where it does not collide with the rod guide 17 inside the rod side chamber 37B as shown in FIG. 1, and the rebound spring 70 is compressed. Does not deform. On the other hand, when the hydraulic shock absorber 10 is fully extended, the piston rod 12 is extended, the second collar 60 abuts the rod guide 17, and between the flange portion 52 of the first collar 50 and the flange portion 62 of the second collar 60. Then, the rebound spring 70 is compressed and deformed to a constant compression length, and the maximum extension stroke of the hydraulic shock absorber 10 is restricted.

  The hydraulic shock absorber 10 includes a bump stopper 22 on the outer surface of the upper end portion of the damper tube 11, and a bump rubber (not shown) included in the piston rod 13 abuts against the bump stopper 22 to restrict the maximum compression stroke.

  However, in the hydraulic shock absorber 10, the first and second collars 50 and 60 are cracked while the inner diameter of the rebound spring 70 is securely pressed into the cylindrical portions 51 and 61. In order to prevent this, the following configuration is provided.

  As shown in FIGS. 3 and 4, the first collar 50 extends along the axial direction at at least a single position in the circumferential direction of the outer periphery of the cylindrical portion 51, in this embodiment, at three positions spaced at equal intervals in the circumferential direction. An arc-like (or V-shaped) groove 101A is provided. The groove 101 </ b> A is provided on the outer periphery of the cylindrical portion 51 in a range extending from the upper end surface to the intersection with the upper surface of the flange portion 52 (spring seat surface 52 </ b> A).

Similarly, as shown in FIG. 3, the second collar 60 also extends along the axial direction at at least a single position in the circumferential direction of the outer periphery of the cylindrical portion 61, in this embodiment, at three positions with equal intervals in the circumferential direction. An arcuate (or V-shaped) groove 102A is provided. The groove 102 </ b> A is provided in the range extending from the upper end surface to the lower end surface on the outer periphery of the cylindrical portion 61.

  If necessary, the first collar 50 has at least a single position in the circumferential direction of the upper surface (spring seat surface 52A) of the flange portion 52, as shown in FIGS. An arcuate (or V-shaped) groove 101B along the entire radial direction can be provided at three positions. The groove 101B of the flange portion 52 is preferably continuous with the groove 101A of the tubular portion 51 at the intersection between the outer periphery of the tubular portion 51 and the upper surface (spring seat surface 52A) of the flange portion 52.

  Similarly, as shown in FIG. 3, the second collar 60 is also at least at a single position in the circumferential direction of the lower surface of the flange portion 62 (spring seat surface 62A), in this embodiment, at three positions at regular intervals in the circumferential direction. An arcuate (or V-shaped) groove 102B can be provided along the entire radial direction. The groove 102B of the flange portion 62 is preferably continuous with the groove 102A of the tubular portion 61 at the intersection between the outer periphery of the tubular portion 61 and the lower surface (spring seat surface 62A) of the flange portion 62.

According to the present embodiment, the following operational effects can be obtained.
(a) When the rebound spring 70 is surely press-fitted into the tubular portion 51 (61) of the collar 50 (60), the allowance for press-fitting the tubular portion 51 (61) of the collar 50 (60) is excessive. Even in this case, the deformation generated in the collar 50 (60) due to this tightening allowance is absorbed by the presence of the groove 101A (102A) provided in the outer periphery of the cylindrical portion 51 (61), and as a result, the collar 50 ( It is possible to prevent the collar 50 (60) from cracking without increasing the stress generated in 60).

  (b) By providing the groove 101B (102B) also on the upper surface of the flange portion 52 of the collar 50 (60) (or the lower surface of the flange portion 62), the press-fitting to the tubular portion 51 (61) of the collar 50 (60) is achieved. Even when the deformation generated in the collar 50 (60) due to the tightening allowance is large, this deformation is added to the groove 101A (102A) provided on the outer periphery of the cylindrical portion 50 (60) and the upper surface (or the flange portion 52). Absorption is also caused by the presence of the groove 101B (102B) on the lower surface of the flange portion 62. As a result, the stress generated in the collar 50 (60) is not increased, and the collar 50 (60) can be prevented from cracking.

  (c) According to the above (a) and (b), the collar 50 (60) to be loaded at the end of the rebound spring 70, and the rebound spring 70 can be surely press-fitted and does not crack. Can provide.

Example 2 (FIGS. 6 and 7)
The second embodiment is different from the first embodiment in that the first collar 50 (same as the second collar 60) is at least in the circumferential direction of the inner periphery of the cylindrical portion 51 (61) as shown in FIGS. In this embodiment, arc-shaped (or V-shaped) grooves 111A (112A) along the axial direction are provided at three positions at equal intervals in the circumferential direction in this embodiment. The groove 111A (112A) is provided in a range extending from the upper end surface to the lower end surface on the inner periphery of the collar 51 (61).

  If necessary, the first collar 50 (the same applies to the second collar 60) is at least a single position in the circumferential direction of the lower surface of the flange portion 52 (upper surface of the flange portion 62), as shown in FIG. Arc-shaped (or V-shaped) grooves 111B (112B) extending along the entire radial direction can be provided at three positions at regular intervals in the circumferential direction. The groove 111B (groove 112B of the flange portion 62) of the flange portion 52 is an intersection of the inner periphery of the tubular portion 51 (inner periphery of the tubular portion 61) and the lower surface of the flange portion 52 (upper surface of the flange portion 62). It is preferable that the groove 111A of the cylindrical part 51 (the groove 112A of the cylindrical part 61) is continuous.

According to the present embodiment, the following operational effects can be obtained.
(a) When the rebound spring 70 is surely press-fitted into the tubular portion 51 (61) of the collar 50 (60), the allowance for press-fitting the tubular portion 51 (61) of the collar 50 (60) is excessive. Even in this case, the deformation generated in the collar 50 (60) due to this tightening allowance is absorbed by the presence of the groove 111A (112A) provided in the inner periphery of the cylindrical portion 51 (61), and as a result, the collar 50 The stress generated in (60) is not increased, and the collar 50 (60) can be prevented from cracking.

  (b) By providing the groove 111B (112B) also on the lower surface of the flange portion 52 of the collar 50 (60) (or the upper surface of the flange portion 62), press-fitting into the tubular portion 51 (61) of the collar 50 (60) is performed. Even when the deformation generated in the collar 50 (60) due to the tightening margin is large, this deformation is added to the groove 111A (112A) provided on the inner periphery of the cylindrical portion 51 (61) and the lower surface ( Or it absorbs also by presence of the groove | channel 111B (112B) of the upper surface of the flange part 62, As a result, the stress which arises in the collar 50 (60) is not made high, and the crack of the collar 50 (60) can be prevented.

  (c) According to the above (a) and (b), the collar 50 (60) to be loaded at the end of the rebound spring 70, and the rebound spring 70 can be surely press-fitted and does not crack. Can provide.

  Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration of the present invention is not limited to these embodiments, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention.

FIG. 1 is an overall half sectional view showing a hydraulic shock absorber. FIG. 2 is a cross-sectional view illustrating the rebound spring structure according to the first embodiment. FIGS. 3A and 3B show an A portion and a B portion of FIG. 2, in which FIG. 3A is an enlarged view of the lower collar side, and FIG. 3B is an enlarged view of the upper collar side. FIG. 4 is a perspective view showing the collar. FIG. 5 is a perspective view showing a modified example of the collar. 6A and 6B show the main part of the rebound spring structure of the second embodiment, where FIG. 6A is an enlarged view of the lower collar side, and FIG. 6B is an enlarged view of the upper collar side. FIG. 7 is a perspective view showing the collar.

Explanation of symbols

10 Hydraulic shock absorber 13 Piston rod 50, 60 Collar 51, 61 Cylindrical part 52, 62 Flange part 101A, 102A Groove 101B, 102B Groove 111A, 112A Groove 111B, 112B Groove

Claims (3)

In the rebound spring structure that loads the collar to the end of the rebound spring of the hydraulic shock absorber,
Using a collar made of resin with a cylindrical part that restrains the inner diameter of the rebound spring and a flange part that receives the end of the rebound spring,
A rebound spring structure for a hydraulic shock absorber, wherein a groove along the axial direction is provided at least at a single position in the circumferential direction of the inner circumference or outer circumference of the cylindrical portion of the collar.   The rebound spring structure of the hydraulic shock absorber according to claim 1, wherein a groove along the radial direction is provided at least at a single position in the circumferential direction of the upper surface or the lower surface of the flange portion of the collar.   The collar used for the rebound spring structure of the hydraulic shock absorber according to claim 1 or 2.

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