JP2018115723A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device which can reduce contact pressure exerted on a shaft of a lip and a housing while inhibiting abnormal deformation of the lip.SOLUTION: A sealing device 100 seals an annular gap between a shaft which relatively moves and a housing and is formed by a rubber elastic body. The sealing device 100 has: an outer periphery lip 120 extending to the sealed object fluid side and the radial outer side; an inner periphery lip 130 extending to the sealed object fluid side and the radial inner side; and an annular groove 140 which is formed so as to connect an inner peripheral surface 121 of the outer periphery lip 120 and an outer peripheral surface 131 of the inner periphery lip 130. Multiple columnar holes 150 extending to the opposite side of the sealed object fluid side are provided at a groove bottom 141 of the annular groove 140 so as to be spaced apart from each other in a circumferential direction.SELECTED DRAWING: Figure 1

Description

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

  As a sealing device made of a rubber-like elastic body that seals an annular gap between a relatively moving shaft and a housing, the sealing device has an outer peripheral lip and an inner peripheral lip and has a substantially U-shaped cross section ( A so-called U-packing is known. This U-packing has the advantage that the sealing performance is improved by applying fluid pressure to an annular groove formed between the outer peripheral lip and the inner peripheral lip.

  However, in general, the shaft and housing materials have a low coefficient of linear expansion and do not change much even in a high-temperature environment, whereas in the case of a sealing device, the coefficient of linear expansion is high, and the outer peripheral lip is radial in a high-temperature environment. It tries to expand outward and the inner peripheral lip tries to expand radially inward. Therefore, the outer peripheral lip is strongly restrained by the shaft hole of the housing, and the inner peripheral lip is strongly restrained by the shaft surface. As a result, plastic deformation (sagging) occurs in the outer peripheral lip and the inner peripheral lip over time. Accordingly, the tightening allowance of the outer peripheral lip and the inner peripheral lip decreases with time, so that leakage easily occurs in an environment where the fluid pressure of the fluid to be sealed is low or when the viscosity of the fluid to be sealed is low. End up.

  Generally, as a measure to maintain the sealing performance over a long period of time, the maximum thickness of the lip (outer lip and inner lip) is increased, or from the outer peripheral side of the outer lip to the inner peripheral side of the inner lip. The maximum width is widened. However, these measures have a problem that the contact pressure to the shaft and the housing increases, and the sliding resistance increases when sliding between the lip and the shaft or the housing. Therefore, measures to lower the rigidity of the lip may be taken by deepening the annular groove. However, in this case, there arises a problem that the lip may be bent and abnormally deformed.

JP2015-31326A

  The objective of this invention is providing the sealing device which can reduce the contact pressure of the lip with respect to a shaft or a housing, suppressing that a lip will deform | transform abnormally.

  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 made of a rubber-like elastic body that seals an annular gap between a relatively moving shaft and a housing,
An outer peripheral lip extending radially outward with respect to the fluid to be sealed and an inner peripheral lip extending radially inward with respect to the fluid to be sealed, and formed so as to connect the inner peripheral surface of the outer peripheral lip and the outer peripheral surface of the inner peripheral lip. A sealing device having an annular groove,
A plurality of cylindrical holes extending in a direction opposite to the fluid to be sealed are provided at the groove bottom of the annular groove at intervals in the circumferential direction.

  According to the present invention, a plurality of holes extending in the circumferential direction are provided at the groove bottom of the annular groove in the sealing device so as to extend in the direction opposite to the fluid to be sealed. Therefore, the adhesion force with respect to the housing of the whole outer periphery lip, and the adhesion force with respect to the axis | shaft of the whole inner periphery lip can be reduced. Therefore, when the outer peripheral lip and the housing slide, these sliding resistances can be suppressed. Further, when the inner peripheral lip and the shaft slide, these sliding resistances can be suppressed. Furthermore, it is possible to reduce the force required when the sealing device is incorporated (attached) to the shaft or the housing.

  Since a plurality of holes are provided at intervals in the circumferential direction, the outer peripheral lip and the inner peripheral lip alternately have high rigidity portions and low portions in the circumferential direction. As described above, since a plurality of high-rigidity portions are provided at intervals in the circumferential direction, it is possible to suppress abnormal deformation such as the lip being curled. Moreover, since a hole is cylindrical, stress concentration can be suppressed and it can suppress that a crack etc. generate | occur | produce from a hole.

  The plurality of holes may be provided at a central position between the base of the outer peripheral lip and the base of the inner peripheral lip.

  Further, it is also preferable that the plurality of holes are provided at positions that are biased toward the root side of the inner peripheral lip among the root of the outer peripheral lip and the root of the inner peripheral lip.

Furthermore, the plurality of holes are
Among the base of the outer peripheral lip and the base of the inner peripheral lip, a plurality of inner peripheral holes provided at positions biased to the base side of the inner peripheral lip,
Among the base of the outer peripheral lip and the base of the inner peripheral lip, a plurality of outer peripheral side holes provided at positions offset toward the base side of the outer peripheral lip, and
It is also preferable that the plurality of inner peripheral holes and the plurality of outer peripheral holes are alternately provided so as to be displaced in the circumferential direction.

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

  As described above, according to the present invention, it is possible to reduce the contact pressure of the lip against the shaft and the housing while suppressing the lip from being deformed abnormally.

1 is a partially broken cross-sectional view of a sealing device according to Embodiment 1 of the present invention. FIG. 2 is a schematic front view of the sealing device according to the first embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a sealing structure in which the sealing device according to Example 1 of the present invention is used. FIG. 4 is a schematic cross-sectional view of a sealing device according to Embodiment 2 of the present invention. FIG. 5 is a schematic front view of a sealing device according to Embodiment 2 of the present invention. FIG. 6 is a schematic cross-sectional view of a sealing device according to Embodiment 3 of the present invention. FIG. 7 is a schematic front view of a sealing device according to Embodiment 3 of the present invention.

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. . The sealing structure to which the sealing device according to the present embodiment is applied includes a relatively moving shaft and housing, and a sealing device that seals an annular gap between the shaft and the housing. The relative movement between the shaft and the housing includes the case where the two or more movements are performed in combination when the reciprocating movement is relatively relative, the relative rotation is performed, or the relative swinging is performed. It is.

Example 1
With reference to FIGS. 1-3, the sealing apparatus which concerns on Example 1 of this invention is demonstrated. 1 is a partially broken cross-sectional view of a sealing device according to Embodiment 1 of the present invention. The sealing device according to the present embodiment has a rotationally symmetric shape except that a plurality of holes are provided at intervals in the circumferential direction. In FIG. 1, the surface of the sealing device includes a central axis of the sealing device. The figure which cut | disconnected the part is shown. FIG. 2 is a schematic front view of the sealing device according to the first embodiment of the present invention. FIG. 2 corresponds to a view seen from the right side in FIG. FIG. 3 is a schematic cross-sectional view of a sealing structure in which the sealing device according to Example 1 of the present invention is used. FIG. 3 shows a cross-sectional view taken along a plane including the central axis of the sealing device, and the depth line is omitted.

<Sealing structure>
With reference to FIG. 3, the sealing structure to which the sealing device according to the present embodiment is applied will be described. The sealing structure according to the present embodiment includes a housing 300 having a shaft hole, a shaft 200 inserted through the shaft hole, and a sealing device 100. In the present embodiment, an annular mounting groove 210 is provided on the outer peripheral surface of the shaft 200. The sealing device 100 is mounted in the mounting groove 210. However, the present invention can also be applied to the case where the sealing device is mounted in an annular groove provided on the inner peripheral surface of the shaft hole of the housing. In FIG. 3, the right side is the sealing target fluid side (H) in which the sealing target fluid (for example, lubricating oil) is sealed, and the left side is the atmosphere side (L).

<Sealing device>
The sealing device 100 according to the present embodiment is made of a rubber-like elastic body. As a material for the rubber-like elastic body, rubber materials in general can be applied. Preferable examples include NBR, ACM, H-NBR, FKM, EPDM, and urethane. The sealing device 100 includes an annular body part (waist part) 110, an outer peripheral lip 120 and an inner peripheral lip 130 provided integrally with the body part 110, an inner peripheral surface 121 of the outer peripheral lip 120, and an outer periphery of the inner peripheral lip 130. And an annular groove 140 formed so as to connect the surface 131. As shown in FIG. 3, the sealing device 100 is mounted such that each lip faces the fluid to be sealed (H). The outer peripheral lip 120 is configured to extend from the body portion 110 to the sealing target fluid side (H) and radially outward, and the tip of the outer peripheral lip 120 is slidably adhered to the inner peripheral surface of the shaft hole of the housing 300. . Further, the inner peripheral lip 130 is configured to extend from the body portion 110 to the sealing target fluid side (H) and radially inward, and the tip of the inner peripheral lip 130 is the outer peripheral surface of the shaft 200 (the groove bottom surface of the mounting groove 210). Close contact with.

  The outer diameter of the outer peripheral lip 120 in a state where no external force is acting is set larger than the inner diameter of the inner peripheral surface of the shaft hole of the housing 300 and has a tightening allowance. Further, the inner diameter of the tip of the inner peripheral lip 130 in a state where no external force is applied is set smaller than the outer diameter of the shaft 200 and has a tightening margin. Therefore, even when the fluid pressure of the fluid to be sealed on the fluid to be sealed side (H) is low, the sealing function is exhibited. In a state where the fluid pressure of the sealing target fluid on the sealing target fluid side (H) is high, the sealing device 100 is in close contact with the side wall surface on the atmosphere side (L) in the mounting groove 210. The outer peripheral lip 120 is pressed radially outward by the fluid pressure, and the inner peripheral lip 130 is pressed radially inward by the fluid pressure.

In the sealing device 100 according to the present embodiment, a cylindrical hole 150 extending on the opposite side (atmosphere side (L)) to the sealing target fluid side (H) is formed in the circumferential direction on the groove bottom 141 of the annular groove 140. A plurality are provided at intervals. In this embodiment, the inner peripheral surface 121 of the outer peripheral lip 120 is tapered, and the outer peripheral surface 131 of the inner peripheral lip 130 is also tapered. A portion connecting these tapered portions is formed of a curved surface having a curved line as shown in FIG. The vicinity of this curved surface corresponds to the groove bottom 141 of the annular groove 140.

  In the present embodiment, the plurality of holes 150 are provided at a central position between the root of the outer peripheral lip 120 and the root of the inner peripheral lip 130 (see FIG. 2). In the example shown in FIG. 2, eight holes 150 are provided at equal intervals. However, the number of holes 150 is not particularly limited, and can be provided in the range of 2 to 32, for example. The plurality of holes 150 are usually preferably provided at equal intervals. Furthermore, in this embodiment, the hole 150 extends so as to be parallel to the central axis of the sealing device 100. However, the hole 150 may extend obliquely with respect to the central axis of the sealing device 100.

<Excellent point of sealing device according to this embodiment>
According to the sealing device 100 according to the present embodiment, a plurality of holes 150 extending to the atmosphere side (L) are provided in the groove bottom 141 of the annular groove 140 at intervals in the circumferential direction. Therefore, the adhesion force of the entire outer peripheral lip 120 to the housing 300 and the adhesion force of the entire inner peripheral lip 130 to the shaft 200 can be reduced. Therefore, when the outer peripheral lip 120 and the housing 300 slide, these sliding resistances can be suppressed. Further, it is possible to reduce a force required when the sealing device 100 is incorporated (attached) to the shaft 200 or the housing 300. Thereby, in order to maintain the sealing performance for a long period of time, the maximum thickness (thickness β in FIG. 1) of the lip (the outer peripheral lip 120 and the inner peripheral lip 130) is increased, or from the outer peripheral surface side of the outer peripheral lip 120. Even if the maximum width (width α in FIG. 1) to the inner peripheral surface side of the inner peripheral lip 130 is increased, the sliding resistance can be suppressed and the force required for incorporation can be reduced. The inner diameter of the hole 150 is preferably set to 10% or more of the width α.

  When the housing 300 is provided with a mounting groove for mounting the sealing device 100 so that the inner peripheral lip 130 and the shaft 200 slide, the sliding between the inner peripheral lip 130 and the shaft 200 is possible. Resistance can be suppressed.

  Since a plurality of holes 150 are provided at intervals in the circumferential direction, the outer peripheral lip 120 and the inner peripheral lip 130 have alternately high rigidity portions and low portions in the circumferential direction. As described above, since a plurality of highly rigid portions are provided at intervals in the circumferential direction, it is possible to suppress abnormal deformation such as the outer peripheral lip 120 or the inner peripheral lip 130 being curled. In addition, since the hole 150 is cylindrical, stress concentration can be suppressed and cracks and the like are prevented from being generated from the hole 150 as compared with a case where a prismatic hole is provided. be able to.

  In the present embodiment, as described above, the configuration in the case where the plurality of holes 150 are provided at the center position between the root of the outer peripheral lip 120 and the root of the inner peripheral lip 130 has been described. However, the position of the hole 150 can be set as appropriate from the viewpoint of the material, shape, and usage environment (heat resistance, oil resistance, durability) of the sealing device 100. In the following embodiment, an example in which the position of the hole 150 is different will be described.

(Example 2)
4 and 5 show a second embodiment of the present invention. In the present embodiment, a configuration will be described in which a plurality of holes are provided at positions that are biased toward the root side of the inner peripheral lip among the roots of the outer peripheral lip and the inner peripheral lip. Example 1 for other configurations and operations
Therefore, the same components are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 4 is a schematic cross-sectional view of a sealing device according to Embodiment 2 of the present invention. FIG. 4 shows a cross-sectional view taken along a plane including the central axis of the sealing device, and the depth line is omitted. FIG. 5 is a schematic front view of a sealing device according to Embodiment 2 of the present invention. However, a part of the schematic front view is enlarged.

  Also in the sealing device 100a according to the present embodiment, as in the case of the first embodiment, the annular body portion (waist portion) 110, the outer peripheral lip 120 and the inner peripheral lip 130 provided integrally with the body portion 110, and the outer periphery It has an annular groove 140 formed so as to connect the inner peripheral surface 121 of the lip 120 and the outer peripheral surface 131 of the inner peripheral lip 130. Since the outer peripheral lip 120 and the inner peripheral lip 130 are as described in the first embodiment, description thereof is omitted.

  Also in the sealing device 100a according to the present embodiment, a cylindrical hole 160 extending on the groove bottom 141 of the annular groove 140 on the side opposite to the fluid to be sealed (H) (atmosphere side (L)) is circumferential. A plurality are provided at intervals. In the present embodiment, the plurality of holes 160 are provided at positions that are biased toward the root side of the inner peripheral lip 130 among the root of the outer peripheral lip 120 and the root of the inner peripheral lip 130. Note that the number of holes 160 is not limited and that it is preferable to provide the holes 160 at regular intervals is the same as in the first embodiment.

  Also in the sealing device 100a according to the present embodiment configured as described above, the same effect as in the first embodiment can be obtained. This embodiment is particularly effective when it is desired to reduce the adhesion force of the entire inner peripheral lip 130 to the shaft 200 due to demands for improving the ease of incorporation into the shaft 200.

(Example 3)
6 and 7 show Embodiment 3 of the present invention. In the present embodiment, a configuration when the arrangement of the plurality of holes is different from that of the first embodiment will be described. Since other configurations and operations are the same as those in the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

  FIG. 6 is a schematic cross-sectional view of a sealing device according to Embodiment 3 of the present invention. FIG. 6 shows a cross-sectional view taken along a plane including the central axis of the sealing device, and the depth line is omitted. FIG. 7 is a schematic front view of a sealing device according to Embodiment 3 of the present invention. However, a part of the schematic front view is enlarged.

  Also in the sealing device 100b according to the present embodiment, as in the case of the first embodiment, the annular body portion (waist portion) 110, the outer peripheral lip 120 and the inner peripheral lip 130 provided integrally with the body portion 110, and the outer periphery It has an annular groove 140 formed so as to connect the inner peripheral surface 121 of the lip 120 and the outer peripheral surface 131 of the inner peripheral lip 130. Since the outer peripheral lip 120 and the inner peripheral lip 130 are as described in the first embodiment, description thereof is omitted.

  Also in the sealing device 100b according to the present embodiment, a cylindrical hole extending in the circumferential direction on the groove bottom 141 of the annular groove 140 on the side opposite to the fluid to be sealed (H) (atmosphere side (L)) is provided in the circumferential direction. A plurality are provided at intervals.

In the present embodiment, the plurality of holes are constituted by a plurality of inner peripheral side holes 170 and a plurality of outer peripheral side holes 180. The plurality of inner peripheral side holes 170 are provided at positions that are biased toward the base side of the inner peripheral lip 130 among the base of the outer peripheral lip 120 and the base of the inner peripheral lip 130. Further, the plurality of outer peripheral side holes 180 are provided at positions that are biased toward the root side of the outer peripheral lip 120 among the roots of the outer peripheral lip 120 and the inner peripheral lip 130. The plurality of inner peripheral holes 170 and the plurality of outer peripheral holes 180 are alternately provided so as to be displaced in the circumferential direction (see FIG. 7). Note that the number of inner peripheral holes 170 and outer peripheral holes 180 is not limited, and that a plurality of holes are preferably provided at equal intervals, as in the case of the first embodiment.

  With the configuration as described above, the same effect as in the first embodiment can be obtained. This embodiment is effective when it is desired to reduce the adhesion force of the entire outer peripheral lip 120 to the housing 300 and to reduce the adhesion force of the entire inner peripheral lip 130 to the shaft 200. Further, since the plurality of inner peripheral holes 170 and the plurality of outer peripheral holes 180 are alternately provided so as to be shifted in the circumferential direction, it is possible to prevent the rigidity from being excessively reduced. Therefore, abnormal deformation of the outer peripheral lip 120 and the inner peripheral lip 130 can be suppressed.

  Although not specifically shown, the inner peripheral lip is formed such that a plurality of holes are provided at positions offset toward the root side of the outer peripheral lip 120 between the root of the outer peripheral lip 120 and the base of the inner peripheral lip 130. It is also possible to adopt a configuration that is not provided at a position biased to the base side of 130. That is, in the third embodiment, a configuration in which only the plurality of outer peripheral holes 180 are provided and the inner peripheral holes 170 are not provided may be employed.

100, 100a, 100b Sealing device 110 Body portion 120 Outer peripheral lip 121 Inner peripheral surface 130 Inner peripheral lip 131 Outer peripheral surface 140 Annular groove 141 Groove bottom 150, 160 hole 170 Inner peripheral side hole 180 Outer peripheral side hole 200 Shaft 210 Mounting groove 300 Housing

Claims (4)

In a sealing device made of a rubber-like elastic body that seals an annular gap between a relatively moving shaft and a housing,
An outer peripheral lip extending radially outward with respect to the fluid to be sealed and an inner peripheral lip extending radially inward with respect to the fluid to be sealed, and formed so as to connect the inner peripheral surface of the outer peripheral lip and the outer peripheral surface of the inner peripheral lip. A sealing device having an annular groove,
A sealing device, wherein a plurality of cylindrical holes extending in the circumferential direction are provided at the groove bottom of the annular groove with an interval in the circumferential direction.   The sealing device according to claim 1, wherein the plurality of holes are provided at a central position between a root of the outer peripheral lip and a root of the inner peripheral lip.   2. The sealing device according to claim 1, wherein the plurality of holes are provided at a position biased toward a root side of the inner peripheral lip among a root of the outer peripheral lip and a root of the inner peripheral lip. The plurality of holes are
Among the base of the outer peripheral lip and the base of the inner peripheral lip, a plurality of inner peripheral holes provided at positions biased to the base side of the inner peripheral lip,
Among the base of the outer peripheral lip and the base of the inner peripheral lip, a plurality of outer peripheral side holes provided at positions offset toward the base side of the outer peripheral lip, and
The sealing device according to claim 1, wherein the plurality of inner peripheral side holes and the plurality of outer peripheral side holes are alternately provided so as to be displaced in the circumferential direction.

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