JPH067219Y2 - Backup ring for packing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of use) The present invention relates to a backup ring applied to various packings such as molded packings such as U-rings and O-rings, and more particularly to an inner ring.

(Prior Art) Conventionally, as a packing backup ring of this type, there is one as shown in FIG. 7, for example. Fig. 7
The backup ring 100 shown in (a) is the packing body 1
The backup ring 102 shown in FIG. 7 (b) is an integral type that is integrally assembled with 01, and is independent of the packing body.

The backup rings 100 and 102 are hard members made of resin or the like, and are used to prevent the rubber packing main body 101 such as a U-ring shown in the drawing from protruding and being damaged.

In order to prevent protrusion damage, such a non-split type is desirable, but the mounting groove is an integral groove,
As shown in the figure, when there is a projection 104 such as a spline in the middle of the rod 103, the backup ring 1
00 and 102 cannot get over the protrusion 104 and cannot be mounted.

Therefore, as shown in FIGS. 8 (a) and 8 (b), each backup ring 105, 106 is divided into one portion, and the division portion 107 is expanded so that the projection 104 can pass through.

(Problems to be solved by the invention) However, in the case of the above-described conventional technique, although the installability is improved by providing the split portion 107, the degree of freedom of the backup rings 105 and 106 at the time of installation is increased, and the split end portion is provided. There was a problem that the sealing performance of the packing body was likely to become unstable due to overlapping of

Further, since the split end face has a high degree of freedom, the split portion 107
The rubber of the packing body 101 may stick out from there, and sticking damage may occur.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a backup ring for packing which is a non-split type and has good wearability.

(Means for Solving the Problems) In order to achieve the above purpose. According to the present invention, in a packing backup ring assembled to a packing body to back up a fluid pressure acting on the packing body, a notch in a direction intersecting a circumferential direction is formed on an inner circumference of the backup ring. Is provided.

(Operation) When the backup ring is attached, if there is a protrusion on the outer circumference of the rod, the cut end of the notch opens, the ring diameter expands, and the protrusion passes.

On the other hand, even if the fluid pressure is applied, the backup ring does not have a split portion, so that the function of preventing the packing body from protruding is maintained.

(Example) Below, this invention is demonstrated based on the Example shown in figure. FIG. 1 shows a packing backup ring according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a packing body made of a rubber-like elastic body, and this embodiment also illustrates a case where the packing body is applied to a U packing similar to the conventional example.

The backup ring 2 is a hard member such as PTFE (tetrafluoroethylene resin) and is integrally assembled to the inner circumference of the packing body 1 and is formed as an endless split type. The backup ring 2 has a substantially cylindrical shape, and one end thereof extends along the inner peripheral lip portion 11 of the packing main body 1 and inclines in a dogleg shape toward the lip tip side.

The backup ring 2 is fitted into a stepped recess 3 provided on the inner circumference of the packing body 1 and is integrally assembled to the packing body 1. A concave groove 4 is engraved on the inner peripheral surface of the stepped concave portion 3, and an annular convex line 5 protruding on the outer periphery of the backup ring 2 is fitted to the packing main body 1 and the backup ring 2 in the axial direction. They are assembled and held together so that they do not move relative to each other.

The heel side end of the packing body 1 of the backup ring 2 described above is located at the end face position of the heel part 12 of the packing body 1, and the lip side end extends to a midway position of the inner peripheral lip part 11.

A plurality of notches 7 extending in the direction intersecting the circumferential direction are provided on the inner circumference of the inclined portion 6 of the backup ring 2. The notch 7 makes it easier for the inclined portion 6 to expand outward.

With regard to the depth, number and length of the cuts 7, an appropriate size is selected in consideration of the rod diameter and the projection of the rod to be overcome.

The inner diameter D of the backup ring 2 is the rod 8 to be mounted.
It is larger than the rod diameter d of α by α.
The inner diameter of the rod is set to a small diameter that bites inward from the outer periphery of the rod. The size of this α is the projection 81 of the rod 8.
It is larger than the protruding height β of.

The crossing angle of the notch 7 with respect to the circumferential direction is not limited and can be set arbitrarily, as long as the inner diameter can be enlarged.

Next, the work of mounting the backup ring having such a configuration on the rod 8 will be described.

The backup ring 2 is previously assembled integrally with the inner circumference of the packing body 1.

Then, the projection 8 such as a spline protruding on the outer periphery of the rod 8
1 is covered with a protective cover 82, and the rod 8 is inserted into the inner circumference of the backup ring 2.

Since the inner diameter D of the backup ring 2 is larger than that of the protrusion 81, the inner periphery of the inclined portion 6 of the backup ring 2 contacts the outer periphery of the protective cover 82 that covers the protrusion 81. Since a large number of notches 7 are formed in the inclined portion 6 in the circumferential direction, when the projection 81 is crossed over, the notch of the notch 7 opens in the circumferential direction, and the inclined portion 6 flexes outward in the radial direction. To expand. Then, the protrusion 81 can be smoothly passed through the protective cover 82, and the packing body 1 can be mounted at a predetermined position of the rod 8. The sloping portion 6 elastically returns to the original shape after overcoming the projection 81 and contracts to the original shape, and the notch 7 is closed.

On the other hand, during the sealing action, the pressure acting on the packing body 1 is taken up by the hard backup ring 2. Since this backup ring 2 has no split portion, it has a high rigidity and can effectively prevent the rubber of the packing body 1 from protruding and being damaged.

Here, the fluid pressure acting on the packing body 1 causes a slight gap to be formed in the notch 7 formed in the backup ring 2, but as shown in FIG. 5, the notch 7 is formed obliquely with respect to the axial direction. If so, the occurrence of the gap can be suppressed as much as possible.

FIG. 6 shows an example of a stand-alone packing backup ring.

The backup ring 16 is an endless washer-shaped member having no split portion, and an inclined lip portion 17 extending inward in the radial direction toward the axial direction is provided at an inner diameter end portion thereof. A large number of notches 18 extending in a direction intersecting the circumferential direction are provided on the inner circumference of the inclined lip portion 17 in the circumferential direction. The inner diameter of the backup ring 16 is also formed to be larger than the rod diameter d by α, and α is set to a value larger than the protrusion width β of the protrusion 81 of the rod 8.

Therefore, when it is attached to the rod 8 having the protrusion 81 as shown in FIG. 3, the inclined lip portion 17 provided at the inner diameter end of the backup ring 2 bends outward around the root. The passage of the protrusion 81 is allowed.

In this embodiment, the U-ring has been described as the packing, but the same applies to other squeeze packing such as X-ring and O-ring.

(Effect of the Invention) The present invention has the above-described configuration and operation, and by forming a notch on the inner circumference of the backup ring,
While the sticking-out preventing function of the packing body is sufficiently maintained, the degree of freedom when mounting the rod can be increased, and the versatility can be enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical cross-sectional view of a main part of a packing backup ring according to an embodiment of the present invention, and FIG. 2 is a vertical cross-sectional view showing a usage state of the packing with a backup ring of FIG. Fig. 3 is an explanatory view showing a mounted state of the backup ring of Fig. 1, Fig. 4 is a schematic view showing a state of a cut portion at the time of mounting of Fig. 3, and Fig. 5 is a backup of Fig. 1. FIG. 6 is a top view showing another mode of the cut portion of the ring, FIG. 6 is a longitudinal sectional view of a main part of a backup ring for packing according to another embodiment of the present invention, and FIGS. 7 (a) and 7 (b) are conventional sectional views. FIGS. 8A and 8B are longitudinal sectional views of essential parts of the backup ring, and FIGS. 9A and 9B are explanatory sectional views showing a state in which the backup ring is mounted. Explanation of reference numerals 1 ... Packing body, 2 ... Backup ring 3 ... Step recess, 4 ... Recessed groove 5 ... Convex line, 6 ... Inclined part 7 ... Notch, 8 ... Rod 81 ... Projection , 82 …… Protective cover 16 …… Backup ring 17 …… Inclined lip, 18 …… Incision

Claims (1)

[Scope of utility model registration request] 1. A backup ring for a packing, which is assembled to a packing main body and backs up a fluid pressure acting on the packing main body, wherein a notch is provided in an inner periphery of the backup ring in a direction intersecting a circumferential direction. A backup ring for packing that is characterized by