JPS5840384Y2 - back spring - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a backup ring used for the backing of a piston, etc., and more specifically, a sliding ring made of a synthetic resin material and a rubber-like elastic material that is easy to install and that constitutes the backing. The present invention provides a backup ring structure with excellent backup ability for the back ring of the present invention.

Conventionally, pressure equipment such as a piston and a cylinder, a piston rod and a cylinder cover, or a rotating shaft and a rotating base, etc., have two members that fit together and move relative to each other in the axial direction or circumferential direction while receiving a load such as hydraulic pressure. As a means of resealing the fitting gap between the two members against the hydraulic pressure, a highly wear-resistant synthetic material such as a fluorine-based resin material is used in an annular groove cut into one of the two members that move relative to each other. A sliding ring made of a resin material is inserted so as to make contact with the sliding peripheral surface of the mating member, and a rubber-like elastic material is inserted between the sliding ring and the bottom peripheral surface of the annular groove. Insert the fitted back ring,
Backing devices are widely used in which a sliding ring is pressed against the sliding peripheral surface of a mating member by the elastic force of the buckling.

When the working fluid pressure is high, in order to prevent the sliding ring from being penetrated into the gap between the two members due to the working fluid pressure, a material that is higher than the material of the sliding ring, such as polyacetal resin, is used. It is known that a backup ring made of a highly elastic synthetic resin material is inserted into the axial end of the sliding ring to support the sliding ring.

Fig. 1 shows a conventional example of this type of backing device, in which a slide made of fluorine-based synthetic resin is installed in an annular groove 4 cut into the circumferential surface of one member 1 of two members that move relative to each other. The movable ring 7 is inserted so as to be in contact with the circumferential surface of the relative movable member 2,
A buck ring 8 made of a rubber-like elastic material is interposed between the sliding ring 7 and the bottom peripheral surface of the annular groove 4 to close the fitting gap 5 between the two members 1 and 2. The sliding ring 7 is pressed against the circumferential surface of the mating member 2 when inserted, and a highly elastic synthetic resin material is inserted into the annular spaces formed at both axial ends of the sliding ring 7 and the buck ring 8. A backup ring 10 made using
This prevents damage from being wedged into the fitting gap 5 by receiving the working pressure that is applied alternately to both the left and right sides in the figure.

In the structure of the backing device described above, in the case where the annular groove 4 is formed by turning as shown in the figure and has a so-called integral structure, when the backup ring 10 and the sliding ring 7 form an endless annular body, Since it is extremely difficult to exceed the side wall of the annular groove 4 and accommodate it in the annular groove 4, the annular groove 4 is cut at at least one point on the circumference and expanded in the radial direction. A method of insertion into the annular groove 4 is used.

Conventionally, the backup ring 10 is usually cut by a plane that includes a radius 12 passing through the cut portion 11 and is parallel to a plane that intersects the central axis 13, as shown in FIGS. 2 and 3. However, in those cut in this way, when subjected to operating pressure, it tends to expand outward and increase the gap formed in the cut portion 11,
In addition, in order to prevent abnormal heat generation and generation of noise due to thermal stress caused by thermal expansion caused by sliding friction, the gap between the cutting parts is set to be the minimum in the thermal expansion state.
At low temperatures, a slight gap is maintained, and the direction of the cut surface is parallel to the plane that includes the radius 12 passing through the cut portion 11 and intersects the central axis 13, as described above, so that the operation When pressure is applied, the acute end piece 16 formed in the cut portion 11 receives an axial load and the opposing cut surface 1
5 to close the gap formed in the cut portion 11, but since a gap remains against the load in the radial direction, a buck ring 8 made of rubber-like elastic material fits into this remaining gap and closes the inside. This causes a so-called bulge-out phenomenon, and as the pressure load is repeatedly applied, this bulge-out phenomenon is also repeated, and as shown in FIG.
is damaged due to fatigue and eventually breaks at this location, further damaging the sliding ring T and causing it to lose its sealing function.

In view of the problems with the backing device using the backup ring according to the prior art described above, the present invention has been developed by making the cutting surface of the backup ring inclined with respect to the tangential direction of the circumference from the inner circumferential side to the outer circumferential side of the annular body. Then, the projected shape of the two end parts sandwiching the cutting part on a plane perpendicular to the central axis of the annular body shows an acute angle at one end and an obtuse angle at the other end, so that the cutting part acts from the inside. Due to the fluid pressure, the end piece on the acute angle side presses against the cut surface on the obtuse angle side, closing the inner circumferential side of the gap formed in the cut part, resulting in the buckling seen in the cut part of the backup ring according to the prior art. This is intended to prevent the phenomenon of protrusion inside the corner and allow the backing device to maintain its normal function for a long period of time.

Theoretically, the angle between the cutting plane and the direction of the cutting line relative to the circumference in the projected shape on a plane perpendicular to the central axis of both end parts sandwiching the cut part is 00 on one side of the acute end part.
It can take a value of ~90°, but the acute-angled end piece receives a pressure load from inside and comes into contact with the cut surface of the obtuse-angled end, closing the gap formed in the cut part and closing the gap. In order to effectively suppress the buckling protrusion phenomenon, it is not preferable to set the above-mentioned angle to a value close to 900 degrees.

Hereinafter, embodiments of the backup ring according to the present invention will be described based on the drawings.

In the embodiment shown in FIGS. 5 and 6, the cut surface of the backup ring extends from the inner circumferential side to the outer circumferential side while maintaining an inclination angle γ with respect to the direction of the tangential line 14 to the circumference of the annular body. One of the two end portions sandwiching the cutting portion 11 has an acute end piece 16 forming an angle γ on the inner peripheral side, and is opposed to the cut surface formed on the other end portion.

When the above-described acute end piece 16 is subjected to a load action due to fluid pressure on its inner peripheral side, it comes into pressure contact with the cut surface 15 of the other opposing end, as shown in a partially enlarged view in FIG. The gap formed in the cutting part 11 is closed, and the buckling is prevented from coming out into the gap and being damaged.

The angle of inclination γ between the cut surface and the tangential line 14 to the circumference of the annular body can be set to any value between Oo and 900, but as described above, it is desirable to avoid a value close to 900.

In other embodiments shown in FIGS. 8 to 10,
The cut portion of the annular body has an inclination angle γ with respect to the direction of the tangential line of the circumference of the annular body from the inner circumferential side to the outer circumferential side, similar to the embodiment shown in FIGS. 5 to 7. Cut surface that maintains and stretches 15
In addition, another cut surface 19 is provided which intersects the central axis 13, including a radius 12 passing through the cut, similar to that in the prior art shown in FIGS. In response to loads from within, the acute end piece 16 facing the cut surface 15 acts to close the gap in the cut section 11; The sharp end piece 16' is configured to close the gap between the cut portion 11.

Since the backup ring of the present invention has the above-described structural requirements, the following effects are brought about.

The cut portion 11 of the annular body provided to facilitate insertion into the annular groove 4 is formed by a cut 'fi15 extending from the inner circumferential side to the outer circumferential side with an inclination angle γ to the direction of the cutting line of the circumference. One of the two end portions sandwiching the cutting portion 11 forms an acute end piece 16 on the inner circumferential side, and when a pressure load is applied from the inside in the radial direction, the cut surface of the other opposing end portion is formed. 15 to close the gap formed in the cut part 11 and prevent the protrusion of the corner 9 of the back ring 8 made of rubber-like elastic material into the gap of the cut part 11. Damage to the buck ring 8 due to the protrusion phenomenon observed in the backing device using the backup ring is prevented, and the backing device can maintain normal function for a long period of time.

In the illustrated embodiment, the backing device is shown as being inserted into the inner member of the two members that fit into each other, but conversely, the backing device is shown as being inserted into the outer member. It is also possible to do so.

Further, in the illustrated embodiment, a cut surface 15 extending from the inside to the outside while maintaining an inclination angle γ with respect to the direction of the cutting line 14 to the circumference is shown as being parallel to the central axis 13. However, even in cases where the angle of inclination is slight, the acute end piece 1
Any material can be used as long as the gap between the cut portion 11 can be closed on the inner circumferential surface side by pressure contact between the cut portion 6 and the opposing cut surface 15.

[Brief explanation of drawings]

Figure 1 is a partial sectional view showing the structure of a backing device in which the backup ring of the present invention is used;
Figure a is a side view of an embodiment of a backup ring according to the prior art, Figure 3 is a plan view of the same, and Figure 4 shows damage inside the corner of a buckling combined with the backup rings of Figures 2 and 3. Partial sectional view showing the situation, No. 5
The figure is a side view of one embodiment of the backup ring according to the present invention, FIG. 6 is a plan view of the same, and FIG. 7 is the state of the cut portion of the embodiment of FIGS. FIG. 8 is a side view showing another embodiment of the backup ring according to the present invention, FIG. 9 is a top view, FIG. 10 is a bottom view, and FIG. FIG. 11 is a perspective view showing the shape of a cut portion of the backup ring in FIG. 10; 1... One member, 2... Opposite member, 4
...Annular groove, 5...Fitting gap, 7...
...Sliding ring, 8...Buck ring, 9
・・・・・・Inside corner, 1o・curve・backup ring, 11・・・cutting part, 12・・・radius, 1
3... Central axis line, 14... Cutting line, 15
...Open cut surface, 16...Acute end piece, 19...
...Other cutting surfaces.

Claims (1)

[Scope of utility model registration request] A cutting portion 11 extending from the inner circumferential side to the outer circumferential side of the annular body is provided at least at one location of the annular body, with an inclination angle γ interposed between it and a tangential line 14 with respect to the circumference of the annular body, and the cutting portion 11 An acute end piece 16 formed on one of the two end portions sandwiching the annular body receives a liquid pressure load acting on the inside of the annular body, and
A backup ring characterized in that it is in pressure contact with a cut surface 15 of the other end portion sandwiching the cut portion 11 so as to close a gap formed in the cut portion 11 on the inner peripheral side.