CN110686036A

CN110686036A - Supporting ring

Info

Publication number: CN110686036A
Application number: CN201910380441.1A
Authority: CN
Inventors: 德永渉
Original assignee: Nok Corp
Current assignee: Nok Corp
Priority date: 2018-07-06
Filing date: 2019-05-08
Publication date: 2020-01-14
Also published as: JP2020008088A

Abstract

The invention provides a support ring, which can prevent the sliding surface of the reciprocating shaft from being damaged even if the metal foreign matter mixed in the oil is immersed between the support ring and the reciprocating shaft. A backup ring 1 is characterized in that it supports an annular washer which is in contact with an outer peripheral surface 102a of a reciprocating shaft 102 disposed in a housing and having a tip end side projecting to the atmosphere side and a base end side positioned on the hydraulic pressure side, wherein a plurality of ribs 6 are formed on an inner peripheral surface 1a facing the outer peripheral surface 102a of the reciprocating shaft 102 over the entire circumference in the axial direction of the reciprocating shaft 102, and the length of the ribs 6 is shorter than the entire axial direction of the backup ring 1.

Description

Supporting ring

Technical Field

The present invention relates to a support ring, and more particularly, to a support ring capable of sufficiently preventing a sliding surface of a reciprocating shaft from being damaged even if a metal foreign matter mixed in oil is interposed between the support ring and the reciprocating shaft.

Background

Conventionally, as shown in fig. 6, in order to ensure pressure resistance, a backup ring 300 is configured by using a backup ring 200 made of, for example, a polyamide resin in combination with a gasket 100 used for a rod seal portion in a high-pressure environment where a hydraulic pressure exceeds 30MPa, such as a hydraulic cylinder or a suspension of a construction machine, and a shock absorber of an automobile (patent document 1). The support ring 300 dampens hydraulic pressure and blocks high temperature oil in case of high load.

The reciprocating shaft 400 is disposed in a casing filled with oil, not shown, and is capable of reciprocating in the axial direction as indicated by an arrow a in fig. 6. The reciprocating shaft 400 has a base end side (right side in fig. 6) located inside the housing and a tip end side (left side in fig. 6) projecting axially outward (hereinafter referred to as "atmospheric side") from an opening end of the housing.

The gasket 100 is integrally formed in an annular shape from a rubber-like elastic material such as urethane. The gasket 100 seals the oil within the housing with an oil seal lip 110. The washer 100 forms an appropriate oil film on the outer peripheral surface (sliding surface) 410 of the reciprocating shaft 400. The support ring 200 is disposed and supported in an annular groove formed in the housing. An annular groove is formed around the outer circumferential surface 410 of the reciprocation shaft 400.

When excessive pressure is applied to the gasket 100, it may be deformed and protrude into an annular gap between the reciprocating shaft 400 and the housing, resulting in breakage. In the support ring 300 formed by using the support ring 200 in combination, the support ring 200 is deformed by pressure and closely attached to the reciprocation shaft 400, thereby suppressing the protrusion of the gasket 100 into the annular gap. Thus, the support ring 200 can maintain the shape of the gasket 100 for a long period of time even under a high-pressure environment, and contributes to an increase in the life of the hydraulic equipment.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. H02-035272

Disclosure of Invention

Technical problem to be solved by the invention

The support ring 200 requires a certain degree of hardness to avoid protruding into the annular gap between the reciprocating shaft 400 and the housing. Therefore, when the metallic foreign matter mixed in the oil is inserted between the support ring 200 and the sliding surface 410 of the reciprocating shaft 400, a high contact pressure is generated between the metallic foreign matter and the reciprocating shaft 400, and as shown in fig. 7, the sliding surface 410 of the reciprocating shaft 400 may be damaged 411. If the sliding surface 410 is damaged 411, oil may leak between the washer 100 and the reciprocating shaft 400.

The following structures exist in the support ring 200: as shown in fig. 6, a plurality of ribs 210 are provided on the inner circumferential surface to reduce a contact area with the sliding surface 410 of the reciprocating shaft 400. By reducing the contact area with the sliding surface 410, the metal foreign matter is prevented from being accumulated between the support ring 200 and the sliding surface 410, and the sliding surface 410 is prevented from being damaged 411.

However, in the support ring 200 having the plurality of ribs 210 over the entire axial length L, the retention of metallic foreign matter cannot be sufficiently prevented, and the sliding surface 410 cannot be sufficiently prevented from being damaged.

Accordingly, an object of the present invention is to provide a support ring capable of sufficiently preventing a sliding surface of a reciprocating shaft from being damaged even if a metal foreign matter mixed in oil enters between the support ring and the reciprocating shaft.

Other problems of the present invention will be apparent from the following description.

Means for solving the technical problem

The above problems are solved by the following inventions.

1. A backup ring for supporting an annular washer in contact with an outer peripheral surface of a reciprocating shaft disposed in a housing and having a tip end side projecting to the atmosphere side and a base end side located on a hydraulic pressure side,

a plurality of ribs are formed on the inner peripheral surface opposite to the outer peripheral surface of the reciprocating shaft along the axial direction of the reciprocating shaft and all over the circumference,

the length of the protruding strip is shorter than the axial full length of the supporting ring.

2. The support ring according to claim 1, wherein the plurality of beads include a hydraulic-side bead group and an atmospheric-side bead group formed on an atmospheric side with respect to the hydraulic-side bead group,

the hydraulic side protruding strip group and the atmospheric side protruding strip group have different angular positions relative to the supporting ring.

3. The support ring of claim 2, wherein the hydraulic-side bead group and the atmospheric-side bead group do not overlap in a circumferential direction.

4. The support ring according to 1, 2 or 3, characterized in that the length of the ribs is 40% to 50% of the axial overall length of the support ring.

5. The support ring as set forth in any one of claims 1 to 4, characterized in that said plurality of beads are formed at equal angular intervals.

6. The support ring according to any one of claims 1 to 5, wherein the width of both end portions of the ridge is narrower than that of a central portion.

Effects of the invention

According to the present invention, it is possible to provide a support ring capable of sufficiently preventing a sliding surface of a reciprocating shaft from being damaged even if a metal foreign matter mixed in oil enters between the support ring and the reciprocating shaft.

Drawings

FIG. 1 is a longitudinal cross-sectional view showing a piston rod seal portion of embodiment 1 using the support ring of the present invention;

FIG. 2 is a longitudinal sectional view showing the support ring shown in FIG. 1;

FIG. 3 is a side view (a), a perspective view (b), and a top view (c) of the bead of the support ring shown in FIG. 1;

FIG. 4 is a side view of a reciprocating shaft employing the support ring of the present invention;

FIG. 5 is a longitudinal cross-sectional view showing a 2 nd embodiment of the support ring of the invention;

FIG. 6 is a longitudinal sectional view showing a conventional support ring;

fig. 7 is a side view showing a reciprocating shaft using a conventional support ring.

Description of the symbols

1-supporting ring, 1 a-inner circumferential surface, 2-piston rod washer, 3-cushion ring, 4-dust seal, 5-U-shaped washer, 6-protrusion, 61-both end portions, 62-center portion, 6 a-hydraulic side protrusion group, 6 b-atmospheric side protrusion group, 101-housing, 101 a-opening portion, 102-reciprocating shaft (piston rod), 102 a-outer circumferential surface, 103-annular groove, 104-atmospheric side annular groove, 105-hydraulic side annular groove

Detailed Description

The following describes a specific embodiment of the present invention.

[ embodiment 1 ]

Fig. 1 is a longitudinal sectional view showing a piston rod seal portion according to embodiment 1 using the support ring of the present invention.

The embodiment 1 of the support ring 1 is used for a piston rod seal portion in a hydraulic cylinder or a suspension of a construction machine, a shock absorber of an automobile, and the like. The present embodiment is applied to a piston rod seal portion employed in a hydraulic cylinder (not shown in the drawings) used as an actuator of a construction machine, a civil engineering machine, a cargo vehicle, or the like.

As shown in fig. 1, a piston rod seal portion is provided between a reciprocating shaft (piston rod) 102 and a housing (cylinder housing) 101, the reciprocating shaft 102 being a movable portion that reciprocates, and the housing 101 being a fixed portion that houses the reciprocating shaft 102. The piston rod seal portion is supported by the housing 101. An opening 101a is provided on the atmosphere side (left side in fig. 1) of the casing 101, and the hydraulic side (right side and inside side in fig. 1) is closed with a cap.

A reciprocating shaft 102 is disposed in the housing 101. The reciprocating shaft 102 has a distal end projecting to the atmosphere from the opening 101a of the housing 101, and a proximal end positioned on the hydraulic pressure side in the housing 101. As shown by an arrow a in fig. 1, the reciprocating shaft 102 can reciprocate in the axial direction.

The piston rod seal portion includes: a piston rod washer 2; a damper ring 3 disposed on the hydraulic side of the piston rod washer 2; and a dust seal 4 disposed on the atmospheric side of the piston rod washer 2. Therefore, the damper ring 3, the rod washer 2, and the dust seal 4 are arranged in this order from the hydraulic side to the atmospheric side.

The piston rod packing 2 is a main seal for preventing hydraulic oil from leaking to the outside, and is mainly formed by an annular U-shaped packing made of a rubber-like elastic material such as urethane, and a flat packing-like support ring is adjacent to the U-shaped packing. The inner peripheral surface of the piston rod washer 2 is pressed against the outer peripheral surface (sliding surface) 102a of the reciprocating shaft 102, and seals a gap between the outer peripheral surface 102a and the inner peripheral surface. The rod washer 2 is accommodated in an annular groove 103 provided on the inner peripheral surface of the housing 101.

The dust seal 4 is integrally formed in a ring shape from an elastic material. The material forming the dust seal 4 is an elastic material capable of sealing a gap between the dust seal and the outer peripheral surface (sliding surface) 102a of the reciprocating shaft 102, and is preferably a synthetic resin material such as various rubbers, urethane, PTPE, and the like. The dust seal 4 is housed in an atmosphere side mounting groove 104 provided on the inner peripheral surface of the housing 101.

The damper ring 3 functions as follows: the shock pressure and the fluctuating pressure at the time of high load are buffered, the high-temperature hydraulic oil is prevented from flowing into the piston rod packing 2 side, and the durability of the piston rod packing 2 is maintained.

The cushion ring 3 is mainly composed of an annular U-shaped washer 5 made of a rubber-like elastic material such as urethane, and the support ring 1 is fitted into the heel portion of the U-shaped washer 5. The U-shaped washer 5 is in contact with the outer peripheral surface 102a of the reciprocating shaft 102. The U-shaped washer 5 is supported by the support ring 1, whereby even if an excessive pressure is applied, it is suppressed that deformation occurs to protrude into the annular gap between the reciprocation shaft 102 and the casing 101. The damper ring 1 is deformed by pressure and closely contacts the reciprocating shaft 102, and the U-shaped washer 5 is prevented from protruding into the annular gap.

These U-shaped gasket 5 and backup ring 1 are housed in a hydraulic-side mounting groove 105 provided on the inner peripheral surface of the housing 101. The hydraulic side mounting groove 105 is located on the hydraulic side in the housing 101, surrounds the outer circumferential surface 102a of the reciprocation shaft 102, and is formed coaxially with the reciprocation shaft 102.

FIG. 2 is a longitudinal sectional view showing the support ring shown in FIG. 1.

As shown in fig. 2, the support ring 1 is formed into a ring shape from a hard material such as polyamide resin. The support ring 1 has a plurality of ribs 6 formed on an inner peripheral surface 1a thereof facing an outer peripheral surface 102a of the reciprocating shaft 102 over the entire circumference in the axial direction of the reciprocating shaft 102.

The outer peripheral surface 102a of the reciprocating shaft 102 contacts only the top portions of the ribs 6, and does not contact the inner peripheral surface 1a other than the ribs 6. An annular gap is formed between the inner peripheral surface 1a other than the ribs 6 and the outer peripheral surface 102a of the reciprocating shaft 102.

FIG. 3 is a side view (a), a perspective view (b), and a top view (c) showing the bead of the support ring shown in FIG. 1.

As shown in fig. 3(a) and (b), the height of each of the ribs 6 is, for example, about 0.05mm, and the annular gap between the inner peripheral surface 1a and the outer peripheral surface 102a other than the ribs 6 satisfies the following condition: the U-shaped washer 5 cannot protrude thereinto even if it is deformed by pressure. The annular gap between the inner circumferential surface 1a and the outer circumferential surface 102a other than the ribs 6 is used for passing a metallic foreign substance mixed in the oil film on the outer circumferential surface 102a of the reciprocating shaft 102.

As shown in fig. 3 b, each ridge 6 has a shape of a part of a cylinder having a radius of about 0.5mm (a semi-cone shape), for example. As shown in fig. 3 a, the upper surface portions of both end portions 61 of each bead 6 (the inner peripheral side of the support ring 1) are, for example, arc-shaped with a radius of about 0.2 mm.

Further, as shown in fig. 3(c), it is also preferable that the cross-sectional shape of the ridge 6 is set to be elliptical, and the width of the both end portions 61 is narrower than the central portion 62. This allows the metal foreign matter mixed in the oil film on the outer peripheral surface 102a to smoothly pass through.

The length T of the ribs 6 is shorter than the axial overall length L of the support ring 1. The length T of the ribs 6 is preferably 40% (2/5) to 50% (1/2), more preferably about 40% (2/5), of the axial entire length L of the support ring 1. Furthermore, the length T of the bead 6 can also be greater than 50% of the axial overall length L of the support ring 1.

Also, the plurality of beads 6 are preferably formed at equal angular intervals with respect to the support ring 1. For example, the plurality of ribs 6 may be formed at equal angular intervals (intervals of 4 °) of 90.

The length, circumferential width and number of the protruding strips 6 are set to satisfy the following conditions: even if the support ring 1 is pressed, the inner peripheral surface 1a other than the respective ribs 6 does not contact the outer peripheral surface 102a of the reciprocating shaft 102. Further, when the contact area between each of the ribs 6 and the outer peripheral surface 102a of the reciprocating shaft 102 is reduced, the surface pressure increases, and the wear of the ribs 6 and the reciprocating shaft 102 increases, and therefore, the length, width, and number of the ribs 6 in the circumferential direction need to be set in consideration of the pressure and temperature conditions to be used. In order to allow the metal foreign matter mixed in the oil film to pass smoothly, the circumferential length and width (area of the top) of the ridge 6 are preferably smaller, and the number is preferably smaller.

When the diameter of the reciprocating shaft 102 is large, it is preferable to increase the number of the ribs 6 so that the interval between the ribs 6 is not excessively large.

FIG. 4 is a side view showing a reciprocating shaft using the support ring of the present invention.

In the damper ring 3 using the backup ring 1, even if metal foreign matter mixed in oil enters between the backup ring 1 and the outer peripheral surface 102a of the reciprocating shaft 102, the metal foreign matter passes through the annular gap between the inner peripheral surface 1a and the outer peripheral surface 102a when the reciprocating shaft 102 moves, and therefore, as shown in fig. 4, contact pressure is not generated between the metal foreign matter and the reciprocating shaft 102, and the outer peripheral surface 102a of the reciprocating shaft 102 is not damaged.

FIG. 5 is a longitudinal sectional view showing embodiment 2 of the support ring of the present invention.

In the support ring 1, as shown in fig. 5, the plurality of beads 6 may include a hydraulic-side bead group 6a and an atmospheric-side bead group 6b formed on the atmospheric side of the hydraulic-side bead group 6 a. In this case, the angular position of the ribs 6 relative to the support ring 1 differs from one another.

In this way, in the carrier ring 1 including the hydraulic pressure side bead group 6a and the atmospheric pressure side bead group 6b, the beads 6 of the hydraulic pressure side bead group 6a and the beads 6 of the atmospheric pressure side bead group 6b are different in angular position from each other with respect to the carrier ring 1, and therefore, when the reciprocation shaft 102 moves, the oil film on the outer peripheral surface 102a of the reciprocation shaft 102 can be stirred, and the metal foreign matter in the oil film can be prevented from being retained. By preventing the metal foreign matter from remaining, the outer peripheral surface 102a of the reciprocating shaft 102 is prevented from being damaged.

In the support ring 1 of this embodiment, the wear resistance of the ridge 6 and the reciprocating shaft 102 can be improved and the deformation of the support ring 1 due to pressure can be prevented by increasing the contact area between the ridge 6 and the reciprocating shaft 102. Further, the support ring 1 can be prevented from being twisted due to contact between the inner peripheral surface without the bead 6 and the reciprocating shaft 102.

The length T of the ribs 6 of the hydraulic side rib group 6a_oPreferably shorter than the axial full length L of the support ring 1. And, the length T of the projected strips 6 of the hydraulic side projected strip group 6a_oMore preferably, the axial length L of the support ring 1 is 40% to 50%, and still more preferably about 40%.

And, the length T of the atmosphere side projecting strip group 6b_aPreferably shorter than the axial full length L of the support ring 1. The length T of the ridges 6 of the atmosphere-side ridge group 6b_aMore preferably, the axial length L of the support ring 1 is 40% to 50%, and still more preferably about 40%.

The length T of the ribs 6 of the hydraulic side rib group 6a_oThe length T of the projected strips 6 of the atmospheric side projected strip group 6b_aThe sum of (a) is preferably shorter than the axial full length L of the support ring. Preferably, the beads 6 of the hydraulic-side bead group 6a and the beads 6 of the atmospheric-side bead group 6b do not overlap in the circumferential direction of the support ring 1.

Preferably, the ribs 6 of the hydraulic-side rib group 6a are formed at equal angular intervals, and the ribs 6 of the atmospheric-side rib group 6b are formed at equal angular intervals. The protrusions of each protrusion group may be formed at equal angular intervals.

The specific configurations, shapes, materials, operations, resins, and the like in the above description of the embodiments are only examples for describing the present invention, and the present invention is not to be construed as being limited by these examples.

Claims

2. The support ring as set forth in claim 1 wherein said plurality of beads includes a hydraulic side bead group and an atmospheric side bead group formed on an atmospheric side compared to the hydraulic side bead group,

3. The support ring as set forth in claim 2 wherein said hydraulic side bead set does not circumferentially overlap said atmospheric side bead set.

4. The support ring according to claim 1, 2 or 3, characterized in that the length of the ribs is 40% to 50% of the axial overall length of the support ring.

5. The support ring as set forth in any of claims 1-4 wherein said plurality of beads are formed at equal angular intervals.

6. The support ring according to any of claims 1 to 5, wherein the width of the end portions of the bead is narrower than the width of the central portion.