JP2019019945A - Sealing device - Google Patents

Abstract

To provide a sealing device which is usable even in high-speed rotation while enhancing pressure resistance.SOLUTION: A sealing device comprises a rubbery elastic body-made rubber ring 120, and a resin-made resin ring 110 fixed to an internal peripheral face of the rubber ring 120 integrally therewith. A pair of first inclined faces 111a, 111b which are contracted in diameters toward axial-line both-end sides from a center of an axial line direction, and a pair of second inclined faces 112a, 112b which are contracted in diameters toward the center of the axial line direction from the axial-line both-end sides are formed at an internal peripheral face side of the resin ring 110. A pair of annular protrusions 113a, 113b are formed of a pair of the first inclined faces 111a, 111b and a pair of the second inclined faces 112a, 112b, and a pair of the annular protrusions 113a, 113b are formed so as to be deflective and deformable toward axial-line both sides from the center of the axial line direction when tightly adhering to a shaft 500.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a sealing device that seals an annular gap between a relatively rotating shaft and a housing.

  An oil seal is widely known as a sealing device that seals an annular gap between a relatively rotating shaft and a housing. However, since an oil seal cannot be used in an environment where the fluid pressure is high, a resin ring made of resin is vulcanized on the inner peripheral surface of a rubber ring made of a rubber-like elastic body when used in a high pressure environment. The sealing device joined by the above is used. With reference to FIG.10 and FIG.11, the sealing device which concerns on a prior art example is demonstrated. FIG. 10 is a schematic cross-sectional view of a conventional sealing device. FIG. 11 is a schematic cross-sectional view of a sealing structure according to a conventional example. 10 and 11, the depth line is omitted and only the cut surface is shown.

  The sealing device 700 according to the conventional example includes a rubber ring 720 made of a rubber-like elastic body and a resin ring 710 made of resin that is integrally fixed to the inner peripheral surface of the rubber ring 720. The resin ring 710 is joined to the rubber ring 720 by vulcanization. The rubber ring 720 is configured by an annular portion having a rectangular cross section, and has an annular groove 721 having an arc-shaped cross section at the center of the outer peripheral surface. Further, the resin ring 710 has an annular groove 711 having an arc-shaped cross section at the center of the inner peripheral surface, and annular convex portions 712a and 712b are provided on both sides of the annular groove 711. The pair of annular projections 712a and 712b has a cylindrical surface at the tip. Further, as a material for the resin ring 710, PTFE (polytetrafluoroethylene) is generally used.

  The sealing device 700 configured as described above is mounted in an annular mounting groove 610 formed on the inner peripheral surface of the housing 600. At this time, the rubber ring 720 is compressed in the radial direction and presses the resin ring 710 inward in the radial direction. Thereby, the surface of the shaft 500 is pressed by the pair of annular convex portions 712a and 712b, and the state of being in close contact with the shaft 500 is maintained. Accordingly, the annular gap between the shaft 500 and the housing 600 is sealed.

  However, since the resin material is less flexible than the rubber material, the resin ring 710 cannot follow the shaft 500 when the shaft 500 and the housing 600 are eccentric when the shaft 500 rotates at high speed. , Sealing performance will be reduced. Therefore, there exists a problem that it is difficult to use for a high-speed rotation use.

Japanese Utility Model Publication No. 2-60768

  The objective of this invention is providing the sealing device which can be utilized also in the case of high speed rotation, improving pressure | voltage resistance.

  The present invention employs the following means in order to solve the above problems.

That is, the sealing device of the present invention is
In a sealing device for sealing an annular gap between a relatively rotating shaft and a housing,
A rubber ring made of rubber-like elastic material;
A resin ring made of resin that is integrally fixed to the inner peripheral surface of the rubber ring;
With
On the inner peripheral surface side of the resin ring, a pair of first inclined surfaces that decrease in diameter from the center in the axial direction toward both ends in the axial direction, and a pair that decreases in diameter from the both ends in the axial direction toward the center in the axial direction. The second inclined surface is formed, and the pair of first inclined surfaces and the pair of second inclined surfaces provide a pair of annular protrusions,
Each of the pair of annular projections is configured to be able to bend and deform from the center in the axial direction toward both sides in the axial direction when closely attached to the shaft.

  According to the present invention, since the resin ring slides on the shaft, the rubber seal can be used under a higher pressure condition than when a rubber seal slides on the shaft. In addition, since the pair of annular projections provided on the resin ring are configured to bend and deform when they are in close contact with the shaft, the maximum surface pressure is increased, and even when the shaft is eccentric with respect to the housing, the sealing performance is improved. Can be obtained. Furthermore, since the resin ring is integrally fixed to the rubber ring, the rubber ring and the resin ring do not move relatively, and the surface pressure distribution on the shaft by the resin ring can be stabilized. . That is, when the rubber ring and the resin ring are not fixed integrally, the position of the rubber ring with respect to the resin ring changes depending on the fluid pressure, so that the surface pressure distribution on the shaft due to the resin ring becomes unstable. On the other hand, in the case of the present invention, the surface pressure distribution can be stabilized.

  The resin ring is made of polytetrafluoroethylene, and when T is the maximum radial thickness of the resin ring and H is the maximum radial thickness of the entire sealing device, T ÷ H is 0.1 or more and 0.2. It may be the following.

  The sealing device may be symmetrical with respect to a plane that passes through the center in the central axis direction and is perpendicular to the central axis.

  Thereby, the stable sealing performance can be obtained by both of the pair of annular protrusions. In addition, the sealing performance is improved even when the pressure on one side is higher than the pressure on the other side and the pressure on the other side is higher than the pressure on the other side through the sealing device. Can be maintained.

  In addition, said each structure can be employ | adopted combining as much as possible.

  As described above, according to the present invention, the pressure resistance can be improved, and it can also be used in the case of high-speed rotation.

FIG. 1 is a schematic cross-sectional view showing a relationship among a sealing device, a shaft, and a housing according to Embodiment 1 of the present invention. FIG. 2 is an enlarged cross-sectional view of the vicinity of the resin ring in the sealing device according to Embodiment 1 of the present invention. FIG. 3 is a schematic cross-sectional view of the sealing structure according to the first embodiment of the present invention. FIG. 4 is a graph showing the relationship between T / H and maximum surface pressure. FIG. 5 is a graph showing the relationship between T / H and maximum surface pressure. FIG. 6 is a graph showing the relationship between T / H and maximum surface pressure retention. FIG. 7 is a graph showing the relationship between T / H and tension. FIG. 8 is a graph showing the relationship between T / H and tension. FIG. 9 is a schematic cross-sectional view of a sealing device according to Embodiment 2 of the present invention. FIG. 10 is a schematic cross-sectional view of a conventional sealing device. FIG. 11 is a schematic cross-sectional view of a sealing structure according to a conventional example.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

Example 1
With reference to FIGS. 1-8, the sealing apparatus which concerns on Example 1 of this invention is demonstrated. FIG. 1 is a schematic cross-sectional view showing a relationship among a sealing device, a shaft, and a housing according to Embodiment 1 of the present invention. The sealing device according to the present embodiment has a rotationally symmetric shape, and FIG. 1 shows a cross-sectional view of the sealing device taken along a plane including the central axis, and the depth line is omitted. Moreover, in order to explain the dimensional relationship of each member, about the sealing device, the state which has not received external force is shown. That is, in FIG. 1, the central axis of the shaft 500, the central axis of the shaft hole of the housing 600, and the central axis of the sealing device 100 are made to coincide with each other. It shows the state that has not received. In addition, the site | part which overlaps with the sealing device 100 among the outer peripheral surfaces of the axis | shaft 500, and the site | part which overlaps with the sealing device 100 among the internal peripheral surfaces of the housing 600 are shown with the dotted line. In the following description, the “axial direction” means a direction in which the central axis of the sealing device 100 or the shaft 500 extends (left and right direction in FIGS. 1 to 3).

  FIG. 2 is an enlarged cross-sectional view of the vicinity of the resin ring in the sealing device according to Embodiment 1 of the present invention. Also in FIG. 2, a cross-sectional view of the sealing device cut along a plane including the central axis of the sealing device is shown, and the depth line is omitted. FIG. 3 is a schematic cross-sectional view of the sealing structure according to the first embodiment of the present invention. 3 also shows a cross-sectional view of the sealing device cut along a plane including the central axis of the sealing device, and the depth line is omitted. 4 and 5 are graphs showing the relationship between T / H and maximum surface pressure (MPa). FIG. 6 is a graph showing the relationship between T / H and maximum surface pressure retention rate (%). 7 and 8 are graphs showing the relationship between T / H and tension (N).

<Sealing structure>
With reference to FIG. 3, the sealing structure to which the sealing device 100 according to the present embodiment is applied will be described. The sealing structure according to the present embodiment includes a shaft 500 and a housing 600 that rotate relatively, and a sealing device 100 that seals an annular gap between the shaft 500 and the housing 600. An annular mounting groove 610 is provided on the inner peripheral surface of the shaft hole of the housing 600. The sealing device 100 is mounted in the mounting groove 610. As a result, the annular gap between the shaft 500 and the housing 600 is sealed. Further, when the shaft 500 and the housing 600 rotate relative to each other, the sealing device 100 does not move relative to the housing 600, but slides between the sealing device 100 and the outer peripheral surface of the shaft 500. Designed to.

<Sealing device>
With reference to FIG.1 and FIG.2, the structure of the sealing device 100 which concerns on a present Example is demonstrated. The sealing device 100 according to the present embodiment includes a rubber ring 120 made of a rubber-like elastic body and a resin ring 110 made of resin that is integrally fixed to the inner peripheral surface of the rubber ring 120. As a material of the resin ring 110, PTFE (polytetrafluoroethylene) can be suitably used. The resin ring 110 is integrally fixed to the rubber ring 120 by being joined (baked) to the rubber ring 120 by vulcanization. Rubber ring 1
Reference numeral 20 denotes an annular portion having a rectangular cross section, and an annular groove 121 having a circular cross section in the center of the outer peripheral surface.

  On the inner peripheral surface side of the resin ring 110, a pair of first inclined surfaces 111a and 111b having a diameter reduced from the center in the axial direction toward both ends in the axial direction, and from the both ends in the axial direction toward the center in the axial direction. A pair of second inclined surfaces 112a and 112b are formed. A pair of annular protrusions 113a and 113b is provided by the pair of first inclined surfaces 111a and 111b and the pair of second inclined surfaces 112a and 112b.

  The first inclined surfaces 111a and 111b and the pair of second inclined surfaces 112a and 112b according to the present embodiment are both configured by tapered surfaces. However, the first inclined surface and the second inclined surface in the present invention are not limited to the tapered surface, and an inclined surface that becomes a curved line when viewed in a cross section may be employed. Here, the second inclined surfaces 112a and 112b are configured to be steeper than the first inclined surfaces 111a and 111b. In other words, the inclination of the second inclined surfaces 112a and 112b with respect to the central axis is greater than the inclination of the first inclined surfaces 111a and 111b with respect to the central axis.

  The pair of annular protrusions 113a and 113b are desirably formed only by the first inclined surfaces 111a and 111b and the pair of second inclined surfaces 112a and 112b, as shown in the figure. In this case, the tips of the pair of annular protrusions 113a and 113b have a sharp shape. However, for reasons such as a manufacturing method, a minute cylindrical surface may be formed at the tips of the pair of annular protrusions 113a and 113b. In addition, the first inclined surface 111a and the first inclined surface 111b may be directly intersected as illustrated, or may be connected by a curved surface (so-called R surface).

  Further, the sealing device 100 according to the present embodiment is symmetrical with respect to a plane that passes through the center in the central axis direction (that is, the center in the left-right direction in FIG. 1) and is perpendicular to the central axis. It is configured.

  According to the sealing device 100 configured as described above, when the pair of annular protrusions 113a and 113b provided on the resin ring 110 are in close contact with the shaft 500, the axial direction extends from the center in the axial direction. It is deformed while being bent toward both sides (see arrow U in FIG. 3).

<Excellent point of sealing device according to this embodiment>
According to the sealing device 100 according to the present embodiment, since the resin ring 110 slides on the shaft 500, it is used under a higher pressure condition than in the case where a rubber seal slides on the shaft, such as an oil seal. be able to. Further, since the pair of annular protrusions 113 a and 113 b provided on the resin ring 110 are configured to bend and deform when they are in close contact with the shaft 500, the maximum surface pressure is increased, and the shaft 500 is formed with respect to the housing 600. Even in the case of eccentricity, sealing performance can be obtained. That is, the pressing force accompanying the compression of the rubber ring 120 acts on the resin ring 110, and the repulsive force accompanying the bending deformation of the resin ring 110 acts near the tips of the pair of annular protrusions 113a and 113b. Accordingly, the maximum surface pressure applied to the shaft 500 by the resin ring 110 is increased, and the pair of annular protrusions 113a and 113b are bent and deformed, so that the eccentricity of the shaft 500 with respect to the housing 600 can be followed. Furthermore, since the resin ring 110 is fixed integrally with the rubber ring 120, the rubber ring 120 and the resin ring 110 do not move relative to each other, and the surface pressure distribution on the shaft 500 by the resin ring 110 is prevented. Can be stabilized. That is, when the rubber ring and the resin ring are not fixed integrally, the position of the rubber ring with respect to the resin ring changes depending on the fluid pressure, so that the surface pressure distribution on the shaft due to the resin ring becomes unstable. On the other hand, in this embodiment, the surface pressure distribution can be stabilized.

  Further, the sealing device 100 according to the present embodiment has a symmetrical shape with respect to a plane that passes through the center in the central axis direction and is perpendicular to the central axis. Thereby, the stable sealing performance can be obtained by both the pair of annular protrusions 113a and 113b. Further, the pressure on one side (for example, the left side in FIG. 3) is higher than the pressure on the other side (for example, the right side in FIG. 3) via the sealing device 100, and the pressure on the other side is higher than the pressure on the one side. The sealing performance can be maintained even in the case where the state where the height becomes higher changes.

  Next, the dimensional relationship of each part will be described. In the sealing device 100 according to the present embodiment, it is considered that the relationship between the thickness of the resin ring 110 and the thickness of the entire sealing device affects the sealing performance. Then, the result of having verified about the influence which it has on the sealing performance about the sealing device 100 from which these relationships differ is shown. The comparison with the sealing device 700 according to the conventional example was also verified at the same time.

  The material of the resin ring 110 was PTFE. As shown in FIG. 1, the maximum radial thickness of the resin ring 110 is T, the maximum radial thickness of the entire sealing device 100 is H, and T ÷ H (hereinafter referred to as “T / H”). We verified the proper range. First, in the sealing device 100 according to the present embodiment, the pair of annular protrusions 113a and 113b needs to be provided as described above. As a condition for reliably forming the pair of annular projections 113a and 113b, it is considered that T / H needs to be set to 0.1 or more. The reason for this will be described. The dimension of the sealing device (particularly the dimension in the radial direction) is determined according to the outer diameter of the shaft and the inner diameter of the shaft hole of the housing. In general, a plurality of types of sealing devices having different dimensions are prepared so that different specifications can be used for different shaft outer diameters and housing shaft hole inner diameters. However, a plurality of types of sealing devices having different dimensions usually have a similar shape to the sealing device of the basic size so that a certain quality is maintained. Also in the sealing device 100 according to the present embodiment, verification of an appropriate range of T / H is performed so as to cope with a plurality of types of sizes. In order to reliably form the pair of annular protrusions 113a and 113b, the dimension of T needs to be secured to a certain level or more. Therefore, in the present embodiment, the T / H is set to 0.1 or more in order to ensure a certain dimension of T even in the sealing device 100 having the smallest dimension among a plurality of types of sealing devices 100 having different dimensions. Judged that it is necessary.

  Next, in order to verify the upper limit of T / H, the maximum thickness (HT) in the radial direction of the rubber ring 120 was constant, and the FEM analysis was performed on the sealing devices 100 having different Ts. The sealing device 700 according to the conventional example also has the same dimensions except that the shape of the resin ring 710 is different. Specifically, FEM analysis was performed on the relationship between T / H and maximum surface pressure (MPa) and the relationship between T / H and compression force (N) separately when the crushing rate was large and small. . The “crushing rate” indicates the ratio of the compression amount in the radial direction of the rubber ring 120, and the crushing rate (%) = ((H−W) ÷ (H−T)) × 100 (%). . In the verification, the above FEM analysis was performed separately when the crushing rate was large (crushing rate = A) and small (crushing rate = 0.45A). Note that W is the distance from the groove bottom of the mounting groove 610 to the outer peripheral surface of the shaft 500, as shown in FIG. That is, W is the width in the radial direction of the portion where the sealing device 100 is mounted.

  Here, the surface pressure of the resin ring 110 against the surface of the shaft 500 is different in the axial direction. In the case of the present embodiment, the surface pressure in the vicinity of the tip of each of the pair of annular protrusions 113a and 113b is the highest. Generally, the greater the maximum surface pressure, the higher the sealing performance. Further, the tension force corresponds to the total force for tightening the shaft 500.

  4 to 8 are graphs showing the analysis results. In each graph, the dotted line indicates the analysis result in the case of the sealing device according to the conventional example, and the solid line indicates the analysis result in the case of the sealing device 100 according to the present embodiment.

  4 and 5 are graphs showing the relationship between T / H and the maximum surface pressure. FIG. 4 shows a case where the crushing rate is 0.45 A, and FIG. 5 shows a case where the crushing rate is A. From these analysis results, when the crushing rate is small, the maximum surface pressure decreases as the T / H increases, and when the crushing rate is large, the maximum surface pressure increases as the T / H increases. I understand. FIG. 6 is a graph summarizing the relationship between T / H and maximum surface pressure retention based on these analysis results. Here, the maximum surface pressure retention rate = ((maximum surface pressure when the crushing rate is 0.45 A) / (maximum surface pressure when the crushing rate is A)) × 100 (%).

  When the shaft 500 is eccentric with respect to the housing 600, the crushing rate changes. And even if the crushing rate changes, if the maximum surface pressure is maintained above a certain level, the sealing performance is secured. Moreover, it can be said that the smaller the change in the maximum surface pressure with respect to the change in the crushing rate, the more stable the sealing performance. Accordingly, from FIGS. 4 and 5, when T / H is at least 0.1 or more and 0.4 or less, the case of the sealing device 100 according to the present embodiment is more than the case of the sealing device according to the conventional example. It can be seen that the maximum surface pressure is high and the sealing performance is excellent. In the graph of FIG. 6, it can be said that the higher the maximum surface pressure retention rate, the more stable the sealing performance against changes in the crushing rate. Therefore, from the graph of FIG. 6, if T / H is 0.26 or less, the sealing device 100 according to the present embodiment is more resistant to changes in the crushing ratio than the sealing device according to the conventional example. It can be seen that the sealing performance can be stabilized.

  7 and 8 are graphs showing the relationship between T / H and the tension force, FIG. 7 shows a case where the crushing rate is 0.45 A, and FIG. 8 shows a case where the crushing rate is A. From these analysis results, it can be seen that when the crushing rate is small, the greater the T / H, the smaller the tightening force, and when the crushing rate is large, the greater the T / H, the greater the tightening force. .

  Here, when the shaft 500 is eccentric with respect to the housing 600, the crushing rate changes. In the case where the crushing rate is low, the sealing performance is ensured if the tightening force is maintained above a certain level. In addition, when the crushing rate is high, if the tightening force becomes too high, the rotational torque becomes high. Therefore, it is desirable to keep the tightening force low. From the graph of FIG. 7, when the crushing rate is 0.45 A (when the crushing rate is low), if T / H is 0.25 or less, the case of the sealing device 100 according to the present embodiment is It can be seen that the tightening force can be maintained at a higher value than the sealing device according to the conventional example. Further, from the graph of FIG. 8, when the crushing rate is A (when the crushing rate is high), if T / H is 0.2 or less, the case of the sealing device 100 according to the present embodiment is It can be seen that the tightening force can be suppressed lower than the sealing device according to the conventional example.

  From the above verification results, it is preferable that T / H is 0.1 or more and 0.2 or less. In addition, the suitable dimension of each part in the case of setting to W = 5mm is demonstrated. The distance between the tips of the annular protrusions 113a and 113b of the sealing device 100 is L1, the protrusion amount of the annular protrusions 113a and 113b is T1, the depth of the annular groove 121 is S, and the radius of curvature of the cross section of the annular groove 121 is r. At this time, r = 2.6 mm, T1 = 0.1T to 0.6T (more preferably 0.2T to 0.5T), L1 = 3 mm to 7 mm (more preferably 4 mm to 6 mm), S Is 1 mm or less (more preferably 0.2 mm or more and 0.6 mm or less).

(Example 2)
FIG. 9 shows a second embodiment of the present invention. In this embodiment, the case where the shapes of the resin ring and the rubber ring are different from those of the first embodiment is shown. FIG. 9 is a schematic cross-sectional view of a sealing device according to Embodiment 2 of the present invention. The sealing device according to the present embodiment has a rotationally symmetric shape, and FIG. 9 shows a cross-sectional view of the sealing device taken along a plane including the central axis, and the depth line is omitted.

  Since the sealing structure to which the sealing device 200 according to the present embodiment is applied is the same as that in the first embodiment, the description thereof is omitted.

  Also in the sealing device 200 according to the present embodiment, as in the case of the first embodiment, a rubber ring 220 made of a rubber-like elastic body and a resin resin that is integrally fixed to the inner peripheral surface of the rubber ring 220. And a ring 210. As a material of the resin ring 210, PTFE (polytetrafluoroethylene) can be suitably used. The resin ring 210 is integrally fixed to the rubber ring 220 by being joined (baked) to the rubber ring 220 by vulcanization.

  The rubber ring 220 according to the present embodiment has an annular groove 221 having an arc-shaped cross section at the center of the outer peripheral surface. In addition, both surfaces of the annular groove 221 in the outer peripheral surface of the rubber ring 220 are configured by tapered surfaces 221a and 221b that reduce in diameter as they move away from the center. Then, annular protrusions 223a and 223b are provided on both side surfaces of the rubber ring 220, respectively. The outer peripheral surface side of these annular protrusions 223a and 223b is constituted by tapered surfaces 224a and 224b, and the inner peripheral surface side is also constituted by tapered surfaces 225a and 225b.

  Then, on the inner peripheral surface side of the resin ring 210 according to the present embodiment, a pair of first inclined surfaces 211a that are reduced in diameter from the center in the axial direction toward both ends in the axial direction, as in the case of the first embodiment. 211b, and a pair of second inclined surfaces 212a and 212b that are reduced in diameter from both ends in the axial direction toward the center in the axial direction. A pair of annular protrusions 213a and 213b is provided by the pair of first inclined surfaces 211a and 211b and the pair of second inclined surfaces 212a and 212b.

  The first inclined surfaces 211a and 211b and the pair of second inclined surfaces 212a and 212b according to the present embodiment are both configured by tapered surfaces. However, the first inclined surface and the second inclined surface in the present invention are not limited to the tapered surface, and an inclined surface that becomes a curved line when viewed in a cross section may be employed. Here, the second inclined surfaces 212a and 212b are configured to be steeper than the first inclined surfaces 211a and 211b, as in the case of the first embodiment.

  Further, it is desirable that the pair of annular protrusions 213a and 213b is formed only by the first inclined surfaces 211a and 211b and the pair of second inclined surfaces 212a and 212b as shown in the drawing. In this case, the tips of the pair of annular protrusions 213a and 213b have a pointed shape. However, for reasons such as a manufacturing method, a minute cylindrical surface may be formed at the tips of the pair of annular protrusions 213a and 213b. In addition, the first inclined surface 211a and the first inclined surface 211b may be directly intersected as illustrated, or may be connected by a curved surface (so-called R surface).

  On the outer peripheral surface side of the resin ring 210 according to the present embodiment, an annular groove 214 having an arcuate cross section is provided at the center.

  Furthermore, the sealing device 200 according to the present embodiment is a plane that passes through the center in the central axis direction (that is, the center in the left-right direction in FIG. 9) and is perpendicular to the central axis, as in the first embodiment. It is comprised so that it may become a symmetrical shape.

  According to the sealing device 200 configured as described above, as in the case of the first embodiment, when the pair of annular protrusions 213a and 213b provided on the resin ring 210 are in close contact with the shaft, Also deforms in a state of being bent from the center in the axial direction toward both sides in the axial direction.

Also in the sealing device 200 configured as described above, the same effect as in the case of the first embodiment can be obtained.

100, 200 Sealing device 110, 210 Resin ring 111a, 111b, 211a, 211b Inclined surface 112a, 112b, 212a, 212b Inclined surface 113a, 113b, 213a, 213b Annular protrusion 120, 220 Rubber ring 121, 221 Annular groove 214 Annular groove 221a, 221b Tapered surfaces 223a, 223b Annular projections 224a, 224b Tapered surfaces 225a, 225b Tapered surfaces 500 Shaft 600 Housing 610 Mounting groove

Claims (3)

In a sealing device for sealing an annular gap between a relatively rotating shaft and a housing,
A rubber ring made of rubber-like elastic material;
A resin ring made of resin that is integrally fixed to the inner peripheral surface of the rubber ring;
With
On the inner peripheral surface side of the resin ring, a pair of first inclined surfaces that decrease in diameter from the center in the axial direction toward both ends in the axial direction, and a pair that decreases in diameter from the both ends in the axial direction toward the center in the axial direction. The second inclined surface is formed, and the pair of first inclined surfaces and the pair of second inclined surfaces provide a pair of annular protrusions,
Each of the pair of annular protrusions is configured to be able to bend and deform from the center in the axial direction toward both sides in the axial direction when closely attached to the shaft.   The resin ring is made of polytetrafluoroethylene, and when T is the maximum radial thickness of the resin ring and H is the maximum radial thickness of the entire sealing device, T ÷ H is 0.1 or more and 0.2. The sealing device according to claim 1, wherein:   The sealing device according to claim 1, wherein the sealing device has a symmetrical shape with respect to a plane that passes through the center in the central axis direction and is perpendicular to the central axis.

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