JP2023020610A - Hydraulic shock absorber and suspension device - Google Patents

Abstract

To provide a technology capable of improving strength without slowing reaction in reversing from an extension stroke to a compression stroke.SOLUTION: A hydraulic shock absorber includes: a piston rod 20 formed with a through hole 26; a rebound sheet 150 fixed to an outer side of the piston rod 20; a seal member 110 kept in contact with an inner peripheral surface of an inner cylinder 12; a support member 120 having a cylindrical portion 121 disposed between the piston rod 20 and the seal member 110, and a flange portion 122 projecting to an outer side from the cylindrical portion 121, axially movably supporting the seal member 110, and formed with a through hole 123 in a direction axially crossing the cylindrical portion 121; and a pin 130 inserted to the through hole 26 and the through hole 123 at a position on a side opposite to the rebound sheet 150 with respect to the seal member 110 to determine relative positions of the support member 120 and the piston rod 20, and restricting axial movement of the seal member 110.SELECTED DRAWING: Figure 3

Description

The present invention relates to hydraulic shock absorbers and suspension systems.

Conventionally, there has been proposed a structure that mitigates the shock when the hydraulic shock absorber is extended to its maximum extent. For example, the vibration damper described in Patent Document 1 is configured as follows. That is, the hydraulic end stop has a sealing ring which is arranged between the end stop ring and the closing element and which is axially attached to the end stop ring on one side. supported, radially surrounds the piston rod, is smoothly supported on the piston rod and bears radially on its outer circumferential surface against the inner wall of the control chamber, the sealing ring at least one radial throttle groove, which becomes active in the control chamber upon insertion of the sealing ring and the end stop to provide a predetermined damping between the control chamber and the first working chamber; The medium flow is ensured, and the sealing ring has a plurality of spring tongues, which are supported on the piston rod-side support surface.

Japanese Patent Publication No. 2015-500970

In the technique described in Patent Document 1, high pressure acts on the base end of the spring tongue, so there is room for further improvement in terms of strength. In order to improve the strength and rigidity, it is desirable not to slow down the reaction when reversing from the extension stroke to the compression stroke.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic shock absorber or the like that can increase strength while preventing a slow response when reversing from an extension stroke to a compression stroke.

The present invention, which has been completed for this purpose, includes a piston rod that holds a piston inserted into a cylinder and is formed with a first through hole that intersects with the axial direction; a sealing member arranged outside the piston rod on the side opposite to the piston with respect to the fixing member in the axial direction and in contact with the inner peripheral surface of the cylinder; and the piston rod and the sealing member, and a flange portion protruding outward from the cylindrical portion, and supports the sealing member so as to be movable in the axial direction, A supporting member having a second through hole formed in the tubular portion in a direction intersecting with the axial direction; (2) a restricting member that is passed through the through hole to determine the relative position of the support member and the piston rod, and restricts movement of the seal member in the axial direction.
From another point of view, the present invention provides a piston rod that holds a piston inserted in a cylinder and is formed with a first through hole that intersects with the axial direction; a fixed locking member, a cylindrical collar arranged in the cylinder, a cylindrical collar arranged outside the piston rod and axially opposite the piston with respect to the locking member, the collar a sealing member that contacts the inner peripheral surface of the piston rod and the sealing member; a cylindrical portion arranged between the piston rod and the sealing member; A support member that supports a seal member movably in the axial direction and has a second through hole formed in the tubular portion in a direction that intersects the axial direction; and the fixing member with respect to the seal member. At a position on the opposite side, it is passed through the first through hole and the second through hole to determine the relative position of the support member and the piston rod, and restricts the movement of the seal member in the axial direction. and a regulating member.

According to the present invention, the strength can be increased while the response at the time of reversal from the extension stroke to the compression stroke does not become dull.

It is a figure showing a schematic structure of a suspension system to which a rebound unit concerning a 1st embodiment is applied. It is an example of the perspective view of the parts which comprise the rebound unit which concerns on 1st Embodiment. It is a figure which shows an example of the cross section of the rebound unit which concerns on 1st Embodiment. It is an example of the sectional view of the rebound unit in the extension stroke in which the amount (protrusion amount) of the piston rod protruded from the cylinder portion increases. FIG. 4 is an example of a cross-sectional view of the rebound unit in a compression stroke in which the amount of protrusion of the piston rod is small; It is an example of sectional drawing in the extension process of the rebound unit which concerns on 2nd Embodiment. It is an example of a sectional view in a compression process of a rebound unit concerning a 2nd embodiment. It is an example of sectional drawing in the extension process of the rebound unit which concerns on 3rd Embodiment. It is an example of sectional drawing in the compression process of the rebound unit which concerns on 3rd Embodiment. It is a sectional view showing an example of a schematic structure of a rebound unit concerning a 4th embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
<First embodiment>
FIG. 1 is a diagram showing a schematic configuration of a suspension system 1 to which a rebound unit 100 according to the first embodiment is applied.
The suspension system 1 is a strut-type suspension, and as shown in FIG. The suspension device 1 also includes a lower spring seat 4 that supports a first (lower in FIG. 1) end of the coil spring 3 and a second (upper in FIG. 1) end of the coil spring 3. and an upper spring seat 5 for supporting.

The suspension system 1 is attached to a second end of a piston rod 20, which will be described later. and a wheel-side mounting bracket 7 for mounting the suspension device 1 to the wheel, and a dust cover 8 for covering at least part of the cylinder portion 10 and the piston rod 20 .

The hydraulic shock absorber 2 will be described in detail below.
As shown in FIG. 1 , the hydraulic damping device 2 is a double cylinder hydraulic damping device and includes a cylinder portion 10 , a piston rod 20 , a piston valve 30 and a bottom valve 40 . The hydraulic shock absorber 2 also includes a rebound unit 100 that absorbs shock when the piston rod 20 extends.

[Cylinder part 10]
The cylinder portion 10 includes a thin-walled cylindrical outer cylinder 11, a thin-walled cylindrical inner cylinder 12 housed in the outer cylinder 11, and a cylinder centerline direction of the cylindrical outer cylinder 11 (vertical direction in FIG. 1). and a bottom lid 13 that closes the end of the first side (lower side in FIG. 1). The inside of the outer cylinder 11 is filled with oil. In the following description, the direction of the center line of the cylinder of the outer cylinder 11 may also be referred to as the "axial direction". Also, the first side in the centerline direction may be referred to as the "lower side" and the second side in the centerline direction may be referred to as the "upper side". In some cases, the centerline side in the radial direction from the centerline is referred to as "inner side", and the side opposite to the centerline side is referred to as "outer side".

The cylinder part 10 includes a rod guide 14 that is arranged inside the outer cylinder 11 to cover the upper end of the inner cylinder 12 and movably (slidably) supports the piston rod 20, and an upper end of the outer cylinder 11. and a bump stopper cap 15 attached to the part. Further, the cylinder portion 10 is provided with an oil seal 16 on the upper portion of the outer cylinder 11 to prevent oil from leaking from the outer cylinder 11 and foreign matter from entering the outer cylinder 11 .
The outer peripheral surface of the inner cylinder 12 and the inner peripheral surface of the outer cylinder 11 form a reservoir chamber R in the cylinder portion 10 .

[Piston rod 20]
The piston rod 20 is a solid or hollow rod-shaped member and has a columnar or cylindrical rod portion 21 . In addition, the piston rod 20 has a lower mounting portion 22 for mounting the piston valve 30 on its lower end, and an upper mounting portion 23 for mounting the hydraulic shock absorber 2 to the vehicle body or the like on its upper end. are doing. Male threads are formed at the ends of the lower mounting portion 22 and the upper mounting portion 23 .
Further, the piston rod 20 is formed with a through hole 26 (see FIG. 2) penetrating the rod portion 21 in a direction crossing the axial direction. In this embodiment, the through hole 26 is formed so as to penetrate in a direction orthogonal to the axial direction, in other words, in a radial direction.

[Piston valve 30]
The piston valve 30 includes a piston 31, a lower valve group 32 that closes a lower end of some of the plurality of oil passages formed in the piston 31, and a portion formed in the piston 31. and an upper valve group 33 that closes the upper end of the oil passage.
The piston 31 is in contact with the inner peripheral surface of the inner cylinder 12 via a member provided on the outer peripheral surface thereof for sealing the gap between the outer peripheral surface of the piston 31 and the inner peripheral surface of the inner cylinder 12. A space in which oil is enclosed in 12 is divided into a first oil chamber Y1 below the piston 31 and a second oil chamber Y2 above the piston 31. - 特許庁

[Bottom valve 40]
The bottom valve 40 includes a valve body 41 having a plurality of axially penetrating oil passages, a lower valve 42 provided below the valve body 41, and an upper valve 43 provided above the valve body 41. ing.
A valve body 41 of the bottom valve 40 separates the first oil chamber Y1 and the reservoir chamber R from each other.

[Rebound unit 100]
FIG. 2 is an example of a perspective view of parts constituting the rebound unit 100 according to the first embodiment.
FIG. 3 is a diagram showing an example of a cross section of the rebound unit 100 according to the first embodiment.
The rebound unit 100 includes a seal member 110 that contacts the inner peripheral surface of the inner cylinder 12, and a support member 120 that supports the seal member 110 so as to be axially movable (slidable). Further, the rebound unit 100 includes a pin 130 for positioning the support member 120 to the piston rod 20, a rebound rubber 140 as an example of an annular elastic member arranged above the support member 120, and a rebound rubber 140 fixed to the piston rod 20. A rebound seat 150 is provided.

The seal member 110 is a substantially cylindrical member having a cutout portion 111 formed in a part in the circumferential direction. In other words, the seal member 110 has a C shape when viewed in the axial direction. The outer peripheral surface of the seal member 110 is in contact with the inner peripheral surface of the inner cylinder 12 . The material of the sealing member 110 can be exemplified by metal or resin. Examples of metals include steel and brass, which is a type of alloy of copper and zinc. The resin can be exemplified by polytetrafluoroethylene (PTFE).

The support member 120 has a cylindrical portion 121 and a flange portion 122 provided on the upper portion of the cylindrical portion 121 and protruding outward from the outer peripheral surface of the cylindrical portion 121 . The outer diameter of cylindrical portion 121 is smaller than the inner diameter of sealing member 110 , and the outer diameter of flange portion 122 is greater than the inner diameter of sealing member 110 . The outer diameter of the flange portion 122 is smaller than the inner diameter of the inner cylinder 12 and is set to a size that restricts the downward movement of the rebound rubber 140 .

The support member 120 is arranged outside the piston rod 20 , and the sealing member 110 is arranged outside the cylindrical portion 121 . An even number (for example, two or four) of through-holes 123 penetrating in the radial direction are formed at equal intervals in the circumferential direction in the upper portion of the cylindrical portion 121 and below the flange portion 122 . there is In addition, the axial size of the cylindrical portion 121 from the lower end surface to the through hole 123 is larger than the axial size of the seal member 110 . The material of the support member 120 can be exemplified by metal.

The pin 130 can be exemplified as a split pin made of metal. The pin 130 passes through two opposing through holes 123 of the even number of through holes 123 formed in the cylindrical portion 121 of the support member 120 and the through hole 26 formed in the piston rod 20. to define the position of support member 120 relative to piston rod 20 . After the pin 130 is passed through the two through-holes 123 and 26 , the pin 130 may be plastically deformed at its tip so as not to come out of the two through-holes 123 and 26 .

The rebound seat 150 has a cylindrical portion 151 and a flange portion 152 provided on the upper portion of the cylindrical portion 151 . The outer diameter of the flange portion 152 is smaller than the inner diameter of the inner cylinder 12 and larger than the inner diameter of the seal member 110 . The flange portion 152 restricts downward movement of the seal member 110 .

The rebound seat 150 is made of metal and fixed to the piston rod 20 by welding, for example. Alternatively, the rebound seat 150 may be fixed to the piston rod 20 by, for example, plastically deforming the lower end of the cylindrical portion 151 and crimping it to the piston rod 20 .

(Action of rebound unit 100)
FIG. 4 is an example of a cross-sectional view of the rebound unit 100 in the extension stroke in which the amount of protrusion (protrusion amount) of the piston rod 20 from the cylinder portion 10 increases.
When the amount of protrusion of the piston rod 20 is the largest (hereinafter sometimes referred to as the “maximum extension state”), the rebound rubber 140 contacts the rod guide 14 (see FIG. 1). Due to the presence of the rebound rubber 140, even if the amount of protrusion of the piston rod 20 suddenly increases due to, for example, a dent in the road surface on which the vehicle is running, the rebound rubber 140 absorbs the shock.

As shown in FIG. 4, during the extension stroke in which the piston rod 20 protrudes more, dynamic pressure acts on the upper surface of the seal member 110, so that the lower end surface of the seal member 110 is pressed against the upper surface of the rebound seat 150. be done. Also, the outer peripheral surface of the seal member 110 is in contact with the inner peripheral surface of the inner cylinder 12 . Therefore, in the extension stroke, oil above seal member 110 in second oil chamber Y2 moves downward through notch 111 (see FIG. 2) of seal member 110 . This creates a damping force.

FIG. 5 is an example of a cross-sectional view of the rebound unit 100 during a compression stroke in which the piston rod 20 protrudes less.
When the extension stroke is reversed to the compression stroke in which the amount of protrusion of the piston rod 20 is reduced, dynamic pressure acts on the lower surface of the seal member 110, so that the lower end surface of the seal member 110 rebounds as shown in FIG. As the upper surface of the sheet 150 is separated, the upper end surface of the seal member 110 hits the pin 130 . As a result, as indicated by arrows in FIG. and the gap between the upper surface of the seal member 110 and the flange portion 122 of the support member 120 . Also, the oil below the seal member 110 moves upward through the notch 111 (see FIG. 2) of the seal member 110 . Therefore, during the compression stroke, more oil can be supplied above the seal member 110, and the response when reversing from the extension stroke to the compression stroke is quick.

As described above, the hydraulic shock absorber 2 holds the piston 31 inserted in the inner cylinder 12 as an example of a cylinder, and the through hole as an example of the first through hole in the direction intersecting the axial direction. 26 and a rebound seat 150 as an example of a fixed member fixed to the outside of the piston rod 20 . In addition, the hydraulic shock absorber 2 includes a seal member 110 arranged axially on the opposite side of the rebound seat 150 from the piston 31 outside the piston rod 20 and in contact with the inner peripheral surface of the inner cylinder 12 . ing. Further, the hydraulic shock absorber 2 includes a cylindrical portion 121 as an example of a cylindrical portion disposed between the piston rod 20 and the seal member 110, and a flange portion 122 projecting outward from the cylindrical portion 121. and supporting the seal member 110 so as to be axially movable, and a support member 120 formed with a through hole 123 as an example of a second through hole in a direction intersecting the axial direction in the cylindrical portion 121 I have. Further, the hydraulic shock absorber 2 is passed through the through hole 26 and the through hole 123 at a position on the opposite side of the rebound seat 150 with respect to the seal member 110 to determine the relative positions of the support member 120 and the piston rod 20. A pin 130 is provided as an example of a restricting member that defines and restricts axial movement of the seal member 110 .

In the hydraulic shock absorber 2 configured as described above, the upper portion of the support member 120 supports the rebound rubber 140 when the rebound rubber 140 comes into contact with the rod guide 14 in the fully extended state. A flange portion 122 protruding outward from the outer peripheral surface of the cylindrical portion 121 is provided on the upper portion of the support member 120, and the impact load generated in the rebound rubber 140 is received by the flange portion 122. Damage is suppressed.

Further, as described above, in the compression stroke, oil is supplied above the seal member 110 through the gap between the seal member 110 and the support member 120, so that when the extension stroke is reversed to the compression stroke, Response is fast.
As a result, according to the hydraulic shock absorber 2, it is possible to increase the strength as compared with the configuration described in, for example, Japanese Unexamined Patent Application Publication No. 2002-200011 while preventing the response at the time of reversing from the extension stroke to the compression stroke from slowing down.

Further, in the hydraulic shock absorber 2, the amount of axial displacement of the seal member 110 can be changed simply by changing the axial positions of the through hole 26 of the piston rod 20 and the through hole 123 of the support member 120. Therefore, the degree of freedom in design is high.

<Second embodiment>
FIG. 6 is an example of a cross-sectional view of the rebound unit 200 according to the second embodiment in the extension stroke.
A rebound unit 200 according to the second embodiment differs from the rebound unit 100 according to the first embodiment in that the shape of a seal member 210 corresponding to the seal member 110 and a collar 260 are provided. Differences from the first embodiment will be described below. The same reference numerals are used for the same items in the first embodiment and the second embodiment, and detailed descriptions thereof are omitted.

The rebound unit 200 includes a seal member 210 , a support member 120 , a pin 130 , a rebound rubber 140 , a rebound seat 150 and a collar 260 provided radially outside the seal member 210 .

The sealing member 210 has a cylindrical shape, and unlike the sealing member 110 according to the first embodiment, the notch 111 is not formed. The outer peripheral surface of seal member 210 contacts the inner peripheral surface of collar 260 .

The collar 260 has a cylindrical shape, and is formed with a plurality of grooves 261 recessed from the inner peripheral surface and extending in the axial direction in the circumferential direction. The collar 260 is arranged inside the inner cylinder 12 with its axial upper portion supported by the rod guide 14 . A mode of supporting the collar 260 on the rod guide 14 is not particularly limited. For example, the collar 260 may be screwed or press-fitted to the rod guide 14 .

(Action of rebound unit 200)
In the extension stroke, dynamic pressure acts on the upper surface of seal member 210 as shown in FIG. Also, the outer peripheral surface of the seal member 210 is in contact with the inner peripheral surface of the collar 260 . Therefore, in the extension stroke, the oil above the seal member 210 in the second oil chamber Y2 moves downward through the groove 261 formed in the collar 260, thereby generating a damping force.

FIG. 7 is an example of a cross-sectional view of the rebound unit 200 in the compression stroke according to the second embodiment.
On the other hand, in the compression stroke, oil is supplied above the seal member 210 through the gap between the seal member 210 and the support member 120, similarly to the rebound unit 100 according to the first embodiment. The reaction when reversing from the compression stroke to the compression stroke is fast.

<Third Embodiment>
FIG. 8 is an example of a cross-sectional view of the rebound unit 300 according to the third embodiment in the extension stroke.
A rebound unit 300 according to the third embodiment differs from the rebound unit 100 according to the first embodiment in that it has a seal member 310 corresponding to the seal member 110 and a collar 360 . Differences from the first embodiment will be described below. The same reference numerals are used for the same items in the first embodiment and the third embodiment, and detailed description thereof will be omitted.

The rebound unit 300 includes a seal member 310 , a support member 120 , a pin 130 , a rebound rubber 140 , a rebound seat 150 and a collar 360 provided radially outside the seal member 310 .

Collar 360 is cylindrical. Unlike the collar 260 according to the second embodiment, the collar 360 does not have a groove 261 recessed from the inner peripheral surface. The collar 360 is arranged inside the inner cylinder 12 with its axial upper portion supported by the rod guide 14 .

The seal member 310 is a substantially cylindrical member having a cutout portion 311 formed in a part of the circumferential direction, similarly to the seal member 110 according to the first embodiment, and has a shape of C when viewed in the axial direction. It is glyph-shaped. The outer peripheral surface of seal member 310 contacts the inner peripheral surface of collar 360 .

(Action of rebound unit 300)
In the extension stroke, dynamic pressure acts on the upper surface of seal member 310 as shown in FIG. Also, the outer peripheral surface of the seal member 310 is in contact with the inner peripheral surface of the collar 360 . Therefore, in the extension stroke, oil above seal member 310 in second oil chamber Y2 moves downward through notch 311 of seal member 310 . This creates a damping force.

FIG. 9 is an example of a cross-sectional view of the rebound unit 300 in the compression stroke according to the third embodiment.
On the other hand, in the compression stroke, oil is supplied above the seal member 310 through the gap between the seal member 310 and the support member 120, similarly to the rebound unit 100 according to the first embodiment. The reaction when reversing from the compression stroke to the compression stroke is fast.

<Fourth Embodiment>
FIG. 10 is a cross-sectional view showing an example of a schematic configuration of a rebound unit 400 according to the fourth embodiment.
A rebound unit 400 according to the fourth embodiment differs from the rebound unit 100 according to the first embodiment in that the support member 120 and the rebound rubber 140 are not provided. Differences from the first embodiment will be described below. The same reference numerals are used for the same items in the first embodiment and the fourth embodiment, and detailed description thereof will be omitted.

Rebound unit 400 includes a seal member 410 corresponding to seal member 110 and a pin 430 corresponding to pin 130 .
The pin 430 is passed through the through hole 26 formed in the piston rod 20 .
The seal member 410 is a substantially cylindrical member having a notch (not shown) formed in a part of the circumferential direction, similarly to the seal member 110 according to the first embodiment. The shape is C-shaped. The outer peripheral surface of the seal member 410 contacts the inner peripheral surface of the inner cylinder 12 . Seal member 410 is fixed by being sandwiched between pin 430 and rebound sheet 150 .

The rebound unit 400 configured as described above can also generate a damping force during the extension stroke. Moreover, since the seal member 410 is fixed, it is possible to suppress the generation of noise when the seal member 410 collides with the pin 430 and the rebound seat 150 . In addition, the above effect can be realized with a simple configuration including the seal member 410 and the pin 430 .

DESCRIPTION OF SYMBOLS 1... Suspension system, 2... Hydraulic shock absorber, 3... Coil spring, 10... Cylinder part, 12... Inner cylinder, 14... Rod guide, 20... Piston rod, 26, 123... Through hole, 31... Piston, 100, 200 , 300, 400... Rebound unit 110, 210, 310, 410... Seal member 120... Support member 121... Cylindrical part 122... Flange part 130... Pin 140... Rebound rubber 150... Rebound seat 260 , 360... collar, 261... groove

Claims (7)

a piston rod that holds the piston inserted into the cylinder and has a first through hole that intersects with the axial direction;
a fixing member fixed to the outside of the piston rod;
a seal member arranged outside the piston rod on the opposite side of the fixed member from the piston in the axial direction and in contact with the inner peripheral surface of the cylinder;
A cylindrical portion disposed between the piston rod and the seal member, and a flange portion protruding outward from the cylindrical portion to support the seal member movably in the axial direction. a support member having a second through hole formed in the tubular portion in a direction intersecting the axial direction;
At a position opposite to the fixing member with respect to the seal member, the support member and the piston rod are passed through the first through hole and the second through hole to determine the relative position of the support member and the piston rod. a regulating member that regulates movement of the seal member in the axial direction;
Hydraulic shock absorber. 2. The hydraulic shock absorber according to claim 1, wherein the seal member has a notch formed in a part of the circumferential direction. a piston rod that holds the piston inserted into the cylinder and has a first through hole that intersects with the axial direction;
a fixing member fixed to the outside of the piston rod;
a cylindrical collar disposed within the cylinder;
a seal member arranged outside the piston rod on the opposite side of the fixed member from the piston in the axial direction and in contact with the inner peripheral surface of the collar;
A cylindrical portion disposed between the piston rod and the seal member, and a flange portion protruding outward from the cylindrical portion to support the seal member movably in the axial direction. a support member having a second through hole formed in the tubular portion in a direction intersecting the axial direction;
At a position opposite to the fixing member with respect to the seal member, the support member and the piston rod are passed through the first through hole and the second through hole to determine the relative position of the support member and the piston rod. a regulating member that regulates movement of the seal member in the axial direction;
Hydraulic shock absorber. 4. The hydraulic shock absorber according to claim 3, wherein the sealing member has a notch formed in a part of the circumferential direction. The sealing member is cylindrical,
5. The hydraulic shock absorber according to claim 4, wherein a groove recessed from the inner peripheral surface is formed in the collar so as to extend in the axial direction. a rod guide provided at the axial end of the cylinder and movably supporting the piston rod;
an elastic member provided between the rod guide and the support member;
6. The hydraulic shock absorber according to any one of claims 1 to 5, further comprising: A hydraulic shock absorber according to any one of claims 1 to 6, a coil spring arranged outside the hydraulic shock absorber,
A suspension system with a

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