JPH11325259A - Seal ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal ring which has excellent sealability and producibility by providing circumferential superposition portions with division surfaces formed substantially along the diagonals of rectangular sections of cut portions. SOLUTION: Division surfaces 3, 4 are formed on circumferential superposition portions 5, 6, substantially along the diagonals of rectangular sections on both ends of a cut portion 2. Accordingly, the circumferential superposition portions 5, 6 show substantially triangular columns bent with a curvature of a seal ring 1, respectively provided with tapered surfaces due to the division surfaces 3, 4. With such a setup, amounts of leakage do not differ so much even under application of pressure to sealed fluid from variable sides. Directivity of sealing need not be considered for improving handlability. A leakage amount of the sealed fluid at the cut portion 2 is also reduced. Moldability of the seal ring 1 is improved by selecting PTFE as material, while hardly causing shrinkage, a mold cavity or the like on the circumferential superposition portions 5, 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal ring having a cut portion, and more particularly to a technique characterized by the shape of the cut portion.

[0002]

2. Description of the Related Art Conventionally, an annular seal ring made of a resin material has been used for sealing an annular gap between a shaft hole and a shaft. FIG. 6 shows a seal ring 10 of this kind.
1 is fitted into a groove 102a provided in the shaft 102 to seal a ring-shaped gap 104 between the inner peripheral surface of the shaft hole 103a of the housing 103 and the outer peripheral surface of the shaft 102. FIG.

The main purpose of this seal ring 101 is to prevent the sealing fluid contained in the sealing side M from leaking to the atmosphere side O. As shown in FIG. In some cases, a higher degree of sealing may be exhibited by combining with a sealing means such as an O-ring (not shown) or a sealing device.

When the seal ring is fitted into the groove 102a, if the material of the seal ring 101 is a resin having a predetermined elasticity, the seal ring 101 has a certain degree of elasticity like the O-ring of a rubber-like elastic body. Therefore, the diameter of the shaft 102 may be temporarily expanded to be equal to or slightly larger than the diameter of the shaft 102, the surface of the shaft 102 may be slid and moved to the groove 102a, and the diameter may be reduced at that position. is there.

[0005] However, in the case of a seal ring made of a resin having low elasticity, problems such as cracking when the diameter is expanded or the diameter being expanded without returning to the original size may occur. As shown in FIG. 7A, a cut portion 101a is provided, and the seal ring is once bent in the radially expanding direction and fitted.

Although various shapes of the cut portion 101a have been proposed, FIG. 7B shows a straight cut 101b having a cut surface parallel to the radial direction of the seal ring, and FIG. This is a bias cut 101c that is a cut surface oblique from the radial direction of the seal ring.

[0007] Regarding the shape of the cut portion, the characteristics of the leakage amount with respect to temperature change and pressure change are different from each other.
It is necessary to appropriately adopt a shape that satisfies the required characteristics while taking into account other factors such as durability and cost, but in straight cut and bias cut, the end face of the cut part opens when the diameter is expanded, this part There is a concern that the sealing performance may be deteriorated due to leakage from the pipe.

Therefore, like the step cut 101d shown in FIG. 7D or the special step cut 101f shown in FIG. 7E, the cut portion is provided with a cut surface (joining surface) that overlaps in the circumferential direction. As a result, there has been proposed a type in which the amount of leakage is further reduced. FIG. 7F is an enlarged view of a portion D101 in FIG.

[0009] The straight cut and the bias cut can be provided simply by making a straight cut in the seal ring and are easy to manufacture. Since it takes a long time to manufacture, a seal ring is also manufactured by a molding method such as injection molding or powder compression molding.

[0010]

However, FIG.
Complex shapes such as the special step cut shown in (e) are used for the seal ring by using an injection molding material such as PEEK (polyetheretherketone) or PFA (ethylene tetrafluoride / perfluoroalkoxyethylene). Although it is relatively easy to mold, when a material generally molded by powder compression molding such as PTFE (polytetrafluoroethylene) is used, a desired shape is required due to the complicated shape of the cut portion. It is difficult to accurately mold into a shape, and improvement in manufacturability is desired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a seal ring having a cut portion which has excellent sealability and good manufacturability.

[0012]

In order to achieve the above object, according to the present invention, in a seal ring having a substantially rectangular cross-sectional shape and having a cut portion, the cut portion has a substantially diagonal line of a rectangular cross section. The dividing surface divided along the peripheral overlapping portion is provided.

[0013] Thus, since the cut portion has the circumferential overlapping portion, the amount of leakage at the cut portion is reduced.

Even if the sealing fluid is pressurized from either side, there is no large difference in the amount of leakage, and there is no need to consider the directionality of the seal, and the handling is improved.

[0015] The circumferential overlapping portion is a simple form formed by a division surface divided along a substantially diagonal line of a rectangular cross section, so that manufacturability can be improved.

[0016] It is also preferable that the circumferential overlapping portion has the dividing surface extending from the outer peripheral surface to the inner peripheral surface.

[0017] It is also preferable that the circumferential overlapping portion has the dividing surface extending from one side surface to the other side surface.

[0018] It is also preferable that the circumferential overlapping portion has the dividing surface extending from one side surface to an inner peripheral surface.

It is also preferable that the circumferential overlapping portion has the dividing surface extending from the outer peripheral surface to one side surface.

(2) A seal ring fitted in an annular groove formed on one of the surfaces of the annular gap formed by the opposed surfaces, wherein a gap interval of the annular gap is s,
It is also preferable to provide the dividing surface set so as to satisfy a ≦ s, where a is a separation distance along a wall surface from a corner on the outer peripheral surface side of the rectangular cross section of the dividing surface. .

The axial dimension of the rectangular cross section is H
₀ , the radial dimension is T _0, and the separation distance along the inner peripheral surface from the corner on the inner peripheral surface side of the rectangular cross section of the divided surface is H
_1, when the spaced intervals along the side surface and the T _1, it is preferable with the dividing plane which is set to a relationship of _{H 1 ≦ H 0/2 T} 1 ≦ T 0/2.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIGS. 1 to 3 are diagrams illustrating the configuration of a seal ring 1 according to a first embodiment of the present invention. In FIG. 1, the seal ring 1 is fitted into a groove 102a provided in the shaft 102,
(2) an annular gap 104 between the inner peripheral surface of the shaft hole 103a of the housing 103 as an opposing surface and the outer peripheral surface 102b of the shaft 102;
FIG. 3 is a cross-sectional view of a main part (a view cut in an axial direction) illustrating a state in which is sealed.

FIG. 2 is a sectional view of the seal ring 1, and FIG. 3 is a perspective view. In FIG.
FIG. 3B is a view showing a state where the seal ring 1 is attached as shown in FIG.

In FIG. 1, the seal ring 1 is
The cross section of the cut portion 2 in the SEC1 cross section of FIG. As shown in the figure, the seal ring 1 is an annular member, and has a substantially rectangular cross section.

At both ends of the cut portion 2, divided surfaces 3, 4 divided along substantially diagonal lines of a rectangular cross section are formed in circumferentially overlapping portions 5, 6, respectively. Therefore, the circumferential overlapping portions 5 and 6 have a substantially triangular prism shape bent at the curvature of the seal ring 1, and the divided surfaces 3 and 4 form an inclined surface.

In the seal ring 1 having such a structure, as shown in FIG. 4, even if the sealing fluid is pressurized from either side (pressure Pa, Pb), no large difference occurs in the leakage amount. In addition, it is not necessary to consider the direction of the seal, and the handling is improved.

Further, since the both ends of the cut portion 2 are provided with the circumferentially overlapping portions 5 and 6, the amount of leakage of the sealed fluid in the cut portion 2 can be reduced.

Further, the shape of the cut portion 2 is not provided with a narrow circumferential overlapping portion as in the special step cut shown in FIG. 7 (e), but has a simpler and thicker structure. In the case where PTFE is selected as the base material and a powder compression molding process is used, sinks and burrs are less likely to occur in the circumferential overlapping portions 5 and 6, and the moldability can be improved.

Further, cutting from an annular material by machining can be easily performed by setting the dividing surfaces 3 and 4 to be flat, and the productivity can be improved irrespective of the choice of molding or machining. be able to.

Regarding the axial gap at the ends of the circumferentially overlapping portions 5 and 6 of the cut portion 2, it is preferable that the gap be as small as possible to improve the sealing performance. Since it is conceivable that the interference is increased and the installation becomes difficult, it is preferable to set the inner diameter of the shaft hole 103a to be equal to the outer diameter of the seal ring 1 without any gap in a normal temperature state. .

(Embodiment 2) FIG. 5 is a view for explaining a second embodiment of the present invention. In the first embodiment,
Although the seal ring 1 has a divided surface formed substantially along a diagonal line of a rectangular cross section, it is difficult to form the divided surface completely diagonally in terms of manufacturing.

Further, the circumferential overlapping portion 5 comes into acute contact with the inner circumferential surface of the shaft hole 103a, and there is a concern that deformation due to an increase in contact pressure, durability and sealing performance may be reduced. You.

Therefore, in the second embodiment, a case will be described in which the division surface is formed slightly shifted from the diagonal line. FIG.
In FIG. 5A, the division surface B1 is formed along a diagonal line as in the first embodiment.

FIG. 5 (b) shows the case where the dividing surface B2 is formed so as to extend from the outer peripheral surface to the inner peripheral surface, and FIG. 5 (c) shows that the dividing surface B3 extends from one side surface to the other side surface. FIG. 5 (d) shows a case where the dividing surface B4 is formed so that the dividing surface B4 is directed from one side surface to the inner peripheral surface, and FIG. 5 (e) shows a case where the dividing surface B5 is formed from the outer peripheral surface to one side surface. It is formed as follows.

As shown in FIG. 1, the interval between the annular gaps 104 is s, the axial dimension in a rectangular cross section is H ₀ , and the radial dimension is T ₀ , as shown in FIG.

5 (b) to 5 (e), the separation distance along the wall surface from the corner on the outer peripheral surface 6a side of the rectangular cross section of the divided surface is a, and the inner peripheral surface 5a of the rectangular cross section of the divided surface is from the corners of the side ₁ a spaced interval along the inner circumferential surface H, in the case where the spaced intervals along the side surface and the T _1, FIG. 5 (b) ~
In (e), by setting the relationship of a ≦ s, it is possible to balance the manufacturability and durability while maintaining the above-described non-sealing property of the seal ring.

Further, H ₁ ≦ H _0/2 and T ₁ ≦ T _0/2
The same effect as in the relationship of a ≦ s can be obtained by setting the relationship as follows.

As described above, in the second embodiment, by shifting the division surface within a limited range from the diagonal line, the same operation and effect as in the first embodiment can be exhibited when the seal ring is attached, and Manufacturability can be further improved.

[0039]

As described in the embodiment of the present invention, since the cut portion to which the present invention is applied has the circumferential overlapping portion, the amount of leakage is reduced.

Even if the sealing fluid is pressurized from either side, there is no large difference in the amount of leakage, and it is not necessary to consider the directionality of the seal, and the handling is improved.

The circumferential overlapping portion is a simple form formed by a division surface divided along a substantially diagonal line of a rectangular cross section, so that manufacturability can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a use state of a seal ring according to a first embodiment.

FIG. 2 is a cross-sectional view of the seal ring according to the first embodiment.

FIG. 3 is a perspective explanatory view of a seal ring according to the first embodiment.

FIG. 4 is a sectional view illustrating an operation state of the seal ring according to the first embodiment.

FIG. 5 is a sectional view of a seal ring according to a second embodiment.

FIG. 6 is a cross-sectional configuration explanatory view showing a usage form of a seal ring.

FIG. 7 is a diagram showing a form example of a seal ring.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Seal ring 2 Cut part 3, 4 Dividing surface 5, 6 Circumferential overlapping part 102 Shaft 102a Groove 102b Outer peripheral surface 103 Housing 103a Shaft hole 104 Annular clearance

Claims (7)

[Claims] 1. A seal ring having a substantially rectangular cross-sectional shape and having a cut portion, wherein the cut portion is provided with a divided surface divided along a substantially diagonal line of the rectangular cross section in a circumferential overlapping portion. Seal ring. 2. The seal ring according to claim 1, wherein the circumferential overlapping portion has the divided surface extending from an outer peripheral surface to an inner peripheral surface. 3. The seal ring according to claim 1, wherein the circumferential overlapping portion has the divided surface extending from one side surface to the other side surface. 4. The seal ring according to claim 1, wherein the circumferential overlapping portion has the divided surface extending from one side surface to an inner peripheral surface. 5. The seal ring according to claim 1, wherein the circumferential overlapping portion has the divided surface extending from an outer peripheral surface to one side surface. 6. A seal ring to be fitted in an annular groove formed on any surface of an annular gap formed by two opposing surfaces, wherein a gap interval between the annular gaps is s, and a rectangular cross section of the divided surface is provided. Wherein the separation surface is set so as to satisfy a ≦ s, where a is a separation distance along a wall surface from a corner portion on the outer peripheral surface side of a. The seal ring according to claim 1. 7. An axial dimension in a rectangular cross section is H ₀ ,
The dimension in the radial direction is T ₀ , the spacing from the corner on the inner peripheral surface side of the rectangular cross section of the dividing surface along the inner peripheral surface is H ₁ , and the spacing along the side surface is T ₁
And when, according to any one of _{H 1 ≦ H 0/2 T} 1 ≦ T 0 / claims 2 to 6, characterized in that it comprises 2 to set the dividing plane so that the relationship Seal ring.