JP2021095947A - Sealing device - Google Patents

Abstract

To provide a sealing device capable of suppressing the peeling off of a side lip when installing.SOLUTION: A sealing device is equipped with a reinforcing ring 110, and a sealing device body portion 120 made of an elastic body that has seal lips 122 and 123 integrally provided with the reinforcing ring 110 and slidably provided with respect to a rotary shaft, and a side lip 124 slidably provided on an end surface of a deflector rotating with the rotary shaft. The side lip 124 has an inner peripheral surface 124a and an outer peripheral surface 124b expanding diameters as a sealing object fluid goes from a sealing area side to the opposite side thereof, and a lip tip end surface 124c connecting these inner peripheral surface and outer peripheral surface. On the lip tip end surface, a low friction portion with friction resistance lower than a part of a base material of the sealing device body portion is provided.SELECTED DRAWING: Figure 1

Description

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

In various devices such as a differential device, a sealing device for sealing an annular gap between the rotating shaft and the housing is provided. A sealing device according to a conventional example will be described with reference to FIG. FIG. 6 is a schematic cross-sectional view of the sealing device according to the conventional example. The illustrated sealing device 500 is provided in the differential mechanism in the differential device.

The sealing device 500 includes a reinforcing ring 510 and an elastic sealing device main body 520 integrally provided on the reinforcing ring 510. The sealing device main body portion 520 includes an outer peripheral sealing portion 521 and a seal lip slidably provided with respect to the rotating shaft 200. In this illustrated example, the seal lip is provided with a main lip 522 and a dust strip 523. Further, the sealing device main body 520 also includes a side lip 524 slidably provided on the end surface of the deflector 300, which is a rotating member that rotates together with the rotating shaft 200. The side lip 524 is configured such that its inner peripheral surface side slides with respect to the deflector 300 as shown by the side lip 524a shown by the dotted line in the drawing.

However, when the sealing device 500 is incorporated into the rotating shaft 200, the side lip 524 may be turned over as shown by a solid line in the drawing. That is, the assembling work is performed so that the rotating shaft 200 is relatively inserted from the left side to the right side in the drawing with respect to the sealing device 500. In this process, the deflector 300 abuts on the tip of the side lip 524, and the rotation shaft 200 is further inserted, so that the tip of the side lip 524 usually bends while sliding with respect to the end face of the deflector 300. The side lip 524a shown by the dotted line is in the state. However, due to the frictional resistance at the tip of the side lip 524, the deflector 300 may be turned up so as to bend inward in the radial direction without sliding on the end surface.

Therefore, workability may be reduced, for example, the assembly work must be redone. Further, if the side lip 524 is not noticed to be turned over, the performance of the sealing device 500 is not sufficiently exhibited, so that the durable life of the sealing device 500 may be shortened.

In addition, in order to suppress the turning of the side lip 524, it is conceivable to adopt a configuration in which the tip of the side lip 524 expands more radially outward. However, if such a configuration is adopted, there is a drawback that the desired sealing property cannot be obtained because the side lip 524 slides near the base of the side lip 524 (see Patent Document 1). Therefore, it cannot be said to be the best measure.

International Publication No. 2017/51920

An object of the present invention is to provide a sealing device capable of suppressing the side lip from being turned over at the time of assembling.

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

That is, the sealing device of the present invention
A sealing device that seals an annular gap between a rotating shaft and a housing having a shaft hole through which the rotating shaft is inserted.
Reinforcing ring and
Elasticity having a seal lip integrally provided on the reinforcing ring and slidably provided with respect to the rotating shaft, and a side lip slidably provided on the end face of a rotating member rotating with the rotating shaft. Body-made sealing device body and
With
The side lip has an inner peripheral surface and an outer peripheral surface whose diameter increases from the sealed region side to the opposite side of the sealed fluid, and a lip tip surface connecting the inner peripheral surface and the outer peripheral surface. And
The lip tip surface is provided with a low friction portion having a lower frictional resistance than the base portion of the sealing device main body portion.

According to the present invention, since the low friction portion is provided on the tip surface of the lip, after the end face of the rotating member abuts on the tip of the side lip at the time of assembling, the side lip has a diameter while smoothly sliding on the end face. It deforms so as to bend outward in the direction. Therefore, it is possible to prevent the side lip from being turned over.

The low friction portion may be composed of a plurality of uneven portions.

As a result, the frictional resistance of the low friction portion becomes low.

It is preferable that a lubricant is applied to the surfaces of the plurality of uneven portions.

As a result, the frictional resistance of the low friction portion can be further reduced.

The low friction portion may be made of a material having a lower frictional resistance than the base portion.

Even with such a configuration, the frictional resistance of the low friction portion can be reduced.

It is preferable that the lubricant is applied to the surface of the portion of the material having low frictional resistance.

As a result, the frictional resistance of the low friction portion can be further reduced.

The low friction portion may be formed of a film made of a coated lubricant.

Even with such a configuration, the frictional resistance of the low friction portion can be reduced.

In addition, each of the above configurations can be adopted in combination as much as possible.

As described above, according to the present invention, it is possible to prevent the side lip from being turned over at the time of assembling.

FIG. 1 is a schematic cross-sectional view of the sealing device according to the first embodiment of the present invention. FIG. 2 is an explanatory view at the time of incorporating the sealing device according to the first embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of the sealed structure according to the first embodiment of the present invention. FIG. 4 is a schematic cross-sectional view of the sealing device according to the second embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of the sealing device according to the third embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of the sealing device according to the conventional example.

Hereinafter, embodiments for carrying out the present invention will be described in detail exemplarily based on examples with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention to those unless otherwise specified. ..

(Example 1)
The sealing device according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic cross-sectional view of the sealing device according to the first embodiment of the present invention. FIG. 2 is an explanatory view at the time of incorporating the sealing device according to the first embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of the sealed structure according to the first embodiment of the present invention. The sealing device according to the present embodiment has a rotationally symmetric shape except for a part of the configuration, and the sealing device in FIGS. 1 to 3 has a schematic cross section obtained by cutting the sealing device on a surface including the central axis. Is shown. In the following embodiment, the sealing device 100 provided in the differential mechanism in the differential device will be described as an example.

<Sealed structure>
In particular, with reference to FIG. 3, a sealing structure including the sealing device 100 according to the present embodiment will be described. The sealing structure according to the present embodiment includes a rotating shaft 200, a housing 400 having a shaft hole through which the rotating shaft 200 is inserted, and a sealing device 100 that seals an annular gap between the rotating shaft 200 and the housing 400. Consists of. The rotating shaft 200 is provided with a deflector 300 as a rotating member that rotates together with the rotating shaft 200.

<Seal device>
In particular, the configuration of the sealing device 100 according to the present embodiment will be described with reference to FIGS. 1 and 3. The sealing device 100 according to the present embodiment includes a reinforcing ring 110 made of metal or the like, and an elastic sealing device main body 120 integrally provided on the reinforcing ring 110. The reinforcing ring 110 includes a cylindrical portion 111 and an inward flange portion 112 provided on one end side of the cylindrical portion 111.

The sealing device main body 120 is made of an elastomer material such as rubber. The sealing device main body 120 according to the present embodiment is provided on the outer peripheral surface side of the cylindrical portion 111 of the reinforcing ring 110, and has an outer peripheral sealing portion 121 fixed to the inner peripheral surface of the shaft hole of the housing 400 by fitting. I have. Further, the sealing device main body 120 is provided with a sealing lip that is slidably provided with respect to the rotating shaft 200. In this embodiment, as the seal lip, the main lip 122 for suppressing the leakage of the fluid to be sealed (oil, etc.) and the sealing area (on the right side in FIG. 3) in which the fluid to be sealed is sealed with foreign matter such as dust. A dust strip 123 is provided to prevent the invasion of the region).

The main lip 122 is configured to extend from the vicinity of the tip of the inward flange portion 112 of the reinforcing ring 110 toward the sealed region side. The main lip 122 according to this embodiment is provided with a plurality of screw protrusions 122a for returning the leaked fluid to be sealed to the sealing region.

Further, the dust strip 123 is configured to extend from the vicinity of the tip of the inward flange portion 112 of the reinforcing ring 110 toward the atmospheric region (the region on the left side in FIG. 3) opposite to the sealing region. In this embodiment, a plurality of protrusions 123a are provided on the surface of the dust strip 123 in order to prevent the main lip 122 and the dust strip 123 from hitting the rotating shaft 200 in a solid manner. As a result, when the space between the main lip 122 and the dust strip 123 becomes a negative pressure state, a gap is formed in the vicinity of the respective protrusions 123a due to the deformation of the dust strip 123, and the gas enters the space. It flows in and the negative pressure state is eliminated.

Further, the sealing device main body 120 according to the present embodiment includes a side lip 124 slidably provided on the end surface of the deflector 300. The side lip 124 is provided to prevent dust, muddy water, and the like from entering the seal lip (main lip 122 and dust strip 123) side. The side lip 124 connects the inner peripheral surface 124a and the outer peripheral surface 124b whose diameter increases from the sealed region side to the opposite side of the sealed fluid, and the inner peripheral surface 124a and the outer peripheral surface 124b. It has a lip tip surface 124c. Further, the side lip 124 has a configuration in which a root portion 124X, an abdominal portion 124Y, and a tip portion 124Z are integrally provided in order from the side closer to the reinforcing ring 110 to the side farther away from the reinforcing ring 110. The end surface of the tip portion 124Z corresponds to the above-mentioned tip surface 124c. The root portion 124X is composed of a substantially cylindrical portion, and the abdomen 124Y and the tip portion 124Z are tapered portions whose diameters increase from the sealed region side where the sealing target fluid is sealed toward the opposite side. It is composed of. Further, the abdomen 124Y is configured so that the degree of diameter expansion is larger than that of the tip portion 124X, that is, the taper angle is larger. In this embodiment, the configuration having a cylindrical portion (root portion 124X) is shown, but a configuration without a cylindrical portion can also be adopted. According to the side lip 124 configured as described above, since the tip portion 124Z is configured to bend inward in the radial direction from the abdomen 124Y, the rigidity can be increased. Therefore, it is possible to prevent the contact pressure from dropping even when the contact area becomes large when the tip of the side lip 124 is in contact with the deflector 300.

The lip tip surface 124c is provided with a low friction portion having a lower frictional resistance than the base portion of the sealing device main body 120. The low friction portion according to this embodiment is composed of a plurality of uneven portions 125. The "base portion of the sealing device main body 120" means a portion of the sealing device main body 120 obtained by molding that has not been subjected to various treatments after molding. For example, in this embodiment, the outer peripheral surface 124b of the side lip 124 corresponds to a base portion. Therefore, the frictional resistance of the lip tip surface 124c is lower than the frictional resistance of the outer peripheral surface 124b. The inner peripheral surface 124a of the side lip 124 may be configured to have a low frictional resistance by applying a lubricant such as grease to the surface thereof. As a method for providing the plurality of uneven portions 125, various known satin finish treatment methods (sandblast shot, laser processing, etc.) can be adopted.

<Incorporation of sealing device>
In particular, the procedure for incorporating the sealing device 100 according to the present embodiment will be described with reference to FIG. The assembling work is performed so that the rotating shaft 200 is inserted relative to the sealing device 100 from the left side to the right side in the drawing (see the arrow in the drawing). In this process, the deflector 300 abuts on the tip of the side lip 124, and the rotation shaft 200 is further inserted, so that the tip of the side lip 124 slides with respect to the end face of the deflector 300 and flexes outward in the radial direction. Mu. As a result, the side lip 124 is in the state shown in FIG. Since the rotating shaft 200 slides between the deflector 300 and the side lip 124 during rotation, it is desirable to apply a lubricant (grease) to the inner peripheral surface of the side lip 124 in advance.

<Advantages of the sealing device according to this embodiment>
According to the sealing device 100 according to the present embodiment, the lip tip surface 124c is provided with a low friction portion composed of a plurality of uneven portions 125. As a result, at the time of assembly, after the end face of the deflector 300 abuts on the tip of the side lip 124, the side lip 124 is deformed so as to flex outward in the radial direction while smoothly sliding on the end face. Therefore, it is possible to prevent the side lip 124 from being turned over.

Further, it is also possible to adopt a configuration in which a lubricant (grease or the like) is applied to the surfaces of the plurality of uneven portions 125. As a result, the frictional resistance of the low friction portion can be further reduced, and the turning of the side lip 124 can be suppressed even more reliably.

(Example 2)
FIG. 4 shows Example 2 of the present invention. In the first embodiment, the case where the low friction portion is composed of a plurality of uneven portions is shown. On the other hand, in this embodiment, the case where the low friction portion is made of a material having a lower friction resistance than the base portion of the sealing device main body portion is shown. Since other basic configurations and operations are the same as those in the first embodiment, the same components are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

FIG. 4 is a schematic cross-sectional view of the sealing device according to the second embodiment of the present invention. The sealing device 100a according to the present embodiment has a rotationally symmetric shape except for a part of the configuration, and for the sealing device shown in FIG. 4, a cross section obtained by cutting the sealing device on a surface including the central axis is schematically shown. There is. The sealing structure to which the sealing device 100a according to the present embodiment is applied is the same as that of the first embodiment, and thus the description thereof will be omitted.

The sealing device 100a according to the present embodiment also includes a reinforcing ring 110 and an elastic sealing device main body 120 integrally provided with the reinforcing ring 110, as in the case of the first embodiment. The configuration of the reinforcing ring 110 is as described in the first embodiment.

The sealing device main body 120 according to this embodiment is also made of an elastomer material such as rubber. The sealing device main body 120 according to the present embodiment also includes an outer peripheral sealing portion 121 and a sealing lip (main lip 122 and dust strip 123). These are as described in Example 1 above.

Further, the sealing device main body 120 according to the present embodiment also includes a side lip 124 slidably provided on the end surface of the deflector 300. The side lip 124 has an inner peripheral surface 124a and an outer peripheral surface 124b whose diameter increases as the fluid to be sealed moves from the sealed region side to the opposite side, and a lip tip connecting the inner peripheral surface 124a and the outer peripheral surface 124b. It has a surface 124c. Further, the side lip 124 according to the present embodiment also has a configuration in which the root portion 124X, the abdominal portion 124Y, and the tip portion 124Z are integrally provided.

The lip tip surface 124c is provided with a low friction portion having a lower frictional resistance than the base portion of the sealing device main body 120. The low friction portion according to the present embodiment is made of a material having a lower frictional resistance than the above-mentioned base portion. Hereinafter, the portion of the material having low frictional resistance will be referred to as the low friction material portion 126. As described in Example 1, the "base portion of the sealing device main body 120" means a portion of the sealing device main body 120 obtained by molding that has not been subjected to various treatments after molding. Is.

The low friction material portion 126 can be obtained by applying a coating treatment to the surface of the side lip 124 using a material having a lower frictional resistance than the material (elastomer material) of the sealing device main body portion 120. The low friction material portion 126 in this embodiment is composed of a tip covering portion 126a that covers the lip tip surface 124c and an inner peripheral covering portion 126b that covers a part of the inner peripheral surface 124a.

Also in the sealing device 100a according to the present embodiment configured as described above, the low friction portion composed of the low friction material portion 126 is provided on the lip tip surface 124c. As a result, the same effect as in the case of the first embodiment can be obtained. It is also possible to adopt a configuration in which a lubricant (grease or the like) is applied to the surface of the low friction material portion 126. As a result, the frictional resistance of the low friction portion can be further reduced, and the turning of the side lip 124 can be suppressed even more reliably. In this embodiment, the configuration when the low friction material portion 126 is provided by the coating treatment is shown. However, for example, it is also possible to adopt a configuration in which the low friction material portion is provided by attaching a sheet made of a low friction material (for example, PTFE or the like) to the surface of the side lip 124.

(Example 3)
FIG. 5 shows Example 3 of the present invention. In the first embodiment, the case where the low friction portion is composed of a plurality of uneven portions is shown. On the other hand, in this embodiment, the case where the low friction portion is composed of a film made of the applied lubricant is shown. Since other basic configurations and operations are the same as those in the first embodiment, the same components are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

FIG. 5 is a schematic cross-sectional view of the sealing device according to the third embodiment of the present invention. The sealing device 100b according to the present embodiment has a rotationally symmetric shape except for a part of the configuration, and for the sealing device shown in FIG. 5, a cross section obtained by cutting the sealing device on a surface including the central axis is schematically shown. There is. The sealing structure to which the sealing device 100b according to the present embodiment is applied is the same as that of the first embodiment, and thus the description thereof will be omitted.

The sealing device 100b according to the present embodiment also includes a reinforcing ring 110 and an elastic sealing device main body 120 integrally provided with the reinforcing ring 110, as in the case of the first embodiment. The configuration of the reinforcing ring 110 is as described in the first embodiment.

The sealing device main body 120 according to this embodiment is also made of an elastomer material such as rubber. The sealing device main body 120 according to the present embodiment also includes an outer peripheral sealing portion 121 and a sealing lip (main lip 122 and dust strip 123). These are as described in Example 1 above.

Further, the sealing device main body 120 according to the present embodiment also includes a side lip 124 slidably provided on the end surface of the deflector 300. The side lip 124 has an inner peripheral surface 124a and an outer peripheral surface 124b whose diameter increases as the fluid to be sealed moves from the sealed region side to the opposite side, and a lip tip connecting the inner peripheral surface 124a and the outer peripheral surface 124b. It has a surface 124c. Further, the side lip 124 according to the present embodiment also has a configuration in which the root portion 124X, the abdominal portion 124Y, and the tip portion 124Z are integrally provided.

The lip tip surface 124c is provided with a low friction portion having a lower frictional resistance than the base portion of the sealing device main body 120. The low friction portion according to this embodiment is composed of a film 127 made of a coated lubricant (grease or the like). As described in Example 1, the "base portion of the sealing device main body 120" means a portion of the sealing device main body 120 obtained by molding that has not been subjected to various treatments after molding. Is.

Also in the sealing device 100b according to the present embodiment configured as described above, the lip tip surface 1
The 24c is provided with a low friction portion formed of a film 127 made of a lubricant. As a result, the same effect as in the case of the first embodiment can be obtained.

(Other)
In the above embodiment, the case where the sealing device is used for the differential mechanism has been described as an example. However, the present invention may also be applied to other uses. For example, the sealing device of the present invention can also be applied to devices such as hub bearings.

100, 100a, 100b Sealing device 110 Reinforcing ring 111 Cylindrical part 112 Inward flange part 120 Sealing device main body 121 Outer peripheral sealing part 122 Main lip 122a Screw protrusion 123 Dustrip 123a Protrusion 124 Side lip 124a Inner peripheral surface 124b Outer peripheral surface 124c Lip Tip surface 124X Root 124Y Abdomen 124Z Tip 125 Concavo-convex part 126 Low friction material part 126a Tip covering part 126b Inner circumference covering part 127 Film 200 Rotating shaft 300 Deflector 400 Housing

Claims (6)

A sealing device that seals an annular gap between a rotating shaft and a housing having a shaft hole through which the rotating shaft is inserted.
Reinforcing ring and
Elasticity having a seal lip integrally provided on the reinforcing ring and slidably provided with respect to the rotating shaft, and a side lip slidably provided on the end face of a rotating member rotating with the rotating shaft. Body-made sealing device body and
With
The side lip has an inner peripheral surface and an outer peripheral surface whose diameter increases from the sealed region side to the opposite side of the sealed fluid, and a lip tip surface connecting the inner peripheral surface and the outer peripheral surface. And
A sealing device characterized in that a low friction portion having a lower frictional resistance than a base portion of the sealing device main body portion is provided on the lip tip surface. The sealing device according to claim 1, wherein the low friction portion is composed of a plurality of uneven portions. The sealing device according to claim 2, wherein a lubricant is applied to the surfaces of the plurality of uneven portions. The sealing device according to claim 1, wherein the low friction portion is made of a material having a lower frictional resistance than the base portion. The sealing device according to claim 4, wherein a lubricant is applied to the surface of the portion of the material having low frictional resistance. The sealing device according to claim 1, wherein the low friction portion is composed of a film made of a coated lubricant.

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