JP2021156314A - Sealing device - Google Patents

Abstract

To provide a sealing device which can exert stable sealing performance even in a use environment in which a shaft rotates relatively forwardly and reversely with respect to a housing.SOLUTION: A sealing device 10 for sealing an annular clearance between a relatively-rotating shaft 500 and a housing 600 comprises a first seal 100A which slidbaly contacts with an external peripheral face of the shaft 500 in a state that an internal peripheral end side is deformed so as to be curved toward a sealing-objective region side (O) accompanied by the insertion of the shaft 500, and in a region in which the first seal 100A slides with an external peripheral face of the shaft 500, there are formed a pair of screw pump grooves 111, 112 which extend so that an interval between them becomes narrow as progressing toward an opposite side (A) from a position apart from the opposite side (A) opposite to the sealing-objective region side (O) rather than an end part at the sealing-objective region side.SELECTED DRAWING: Figure 2

Description

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

In a sealing device that seals an annular gap between a relatively rotating shaft and a housing, a seal lip made of a rubber-like elastic body is generally configured to slide on the outer peripheral surface of the shaft. be. However, a resin seal may be used in an environment where the rotation speed of the shaft relative to the housing is high or it is difficult to improve the lubricity. Generally, a resin seal has a lower sealing property than a rubber seal. Therefore, in the sliding region of the resin seal, a screw pump groove or a screw pump protrusion that exerts a screw pump effect that returns the fluid to be sealed that is about to leak to the side to be sealed as the relative rotation with the shaft is provided. The technology to provide is known.

In such a technique, high sealing performance can be exhibited in a usage environment in which the relative rotation direction of the shaft with respect to the housing is determined in one direction. However, the above technique cannot be used in a usage environment in which the shaft rotates in the forward and reverse directions relative to the housing.

Japanese Unexamined Patent Publication No. 2001-165328 Japanese Unexamined Patent Publication No. 2009-204039

An object of the present invention is to provide a sealing device capable of exhibiting stable sealing performance even in a usage environment in which the shaft rotates in the forward and reverse directions relative to the housing.

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 relatively rotating shaft and a housing.
A resin seal that slidably contacts the outer peripheral surface of the shaft in a state in which the inner peripheral end side is deformed so as to be curved toward the sealing target region side with the insertion of the shaft is provided.
In the region of the resin seal that slides on the outer peripheral surface of the shaft, each other is moved from a position distant from the end on the sealing target region side to the opposite side to the sealing target region side toward the opposite side. It is characterized in that a pair of screw pump grooves or screw pump protrusions extending so as to be narrowly spaced are provided.

According to the present invention, when the shaft rotates in a positive direction relative to the housing, leakage is likely to occur due to the screw pump effect of one of the pair of screw pump grooves or one of the pair of screw pump protrusions. The fluid to be sealed can be returned to the area to be sealed. Further, when the shaft rotates in the reverse direction relative to the housing, the fluid to be sealed that is about to leak due to the screw pump effect of the other of the pair of screw pump grooves or the other of the pair of screw pump protrusions. It can be returned to the sealed area side. In this way, the screw pump effect can be exerted in both the case where the shaft rotates relative to the housing in the forward direction and the case where the shaft rotates in the reverse direction. Can be demonstrated.

It is preferable that a plurality of sets of the pair of screw pump grooves or screw pump protrusions are provided at intervals in the circumferential direction.

As a result, the screw pump effect can be exerted at a plurality of locations in the circumferential direction.

The resin seal may be made of a flat washer-shaped member.

It comprises at least one annular member that is fixed to the shaft hole formed in the housing.
The outer peripheral end side of the resin seal may be fixed to the at least one annular member.

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

As described above, according to the present invention, stable sealing performance can be exhibited even in a usage environment in which the shaft rotates in the forward and reverse directions relative to the housing.

FIG. 1 is a partially broken cross-sectional view of the sealing device according to the first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the sealed structure according to the first embodiment of the present invention. FIG. 3 is an explanatory diagram of the mechanism of the sealing device according to the first embodiment of the present invention. FIG. 4 is an explanatory diagram of the mechanism of the sealing device according to the second embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of the sealed structure according to the third embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of the sealed structure according to the fourth embodiment of the present invention. FIG. 7 is a schematic cross-sectional view of the sealed structure according to the fifth embodiment of the present invention.

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 partially broken cross-sectional view of the sealing device according to the first embodiment of the present invention. The sealing device according to the present embodiment has a substantially rotationally symmetric shape, and FIG. 1 shows a cross section obtained by cutting a part of the sealing device on a surface including the central axis of the sealing device. FIG. 2 is a schematic cross-sectional view of the sealed structure according to the first embodiment of the present invention. FIG. 2 shows a cross section of each member cut along a surface including the central axis of the sealing device. Further, in FIG. 2, among the members constituting the sealing structure, only the arrangement positions of the shaft and the housing are shown by dotted lines so that the configuration of the inner peripheral surface of the sealing device can be understood. FIG. 3 is an explanatory diagram of the mechanism of the sealing device according to the first embodiment of the present invention. Note that FIG. 3A shows the state of the inner peripheral surface of the resin seal in a state where the sealing device is attached to the annular gap between the shaft and the housing. Further, FIG. 3B shows a cross-sectional view of the resin seal (corresponding to the AA cross section in FIG. 2) in a state where the sealing device is attached to the annular gap between the shaft and the housing.

<Sealed structure>
A sealing structure to which the sealing device according to the present embodiment is applied will be described with reference to FIG. The sealing structure according to the present embodiment includes a relatively rotating shaft 500 and a housing 600, and a sealing device 10 for sealing an annular gap between the shaft 500 and the housing 600. The sealing device 10 is fixed to the housing 600 and is provided so as to rotate relative to the shaft 500. In the figure, the right side of the sealing device 10 is the sealing target region side (O) in which the sealing target fluid such as oil is sealed. In this embodiment, in the figure, the side opposite to the sealing target region side (O) is exposed to the atmosphere via the sealing device 10. Hereinafter, the side on which the fluid to be sealed is sealed via the sealing device 10 is referred to as the sealing target region side (O), and the opposite side thereof is simply referred to as the opposite side (A).

The sealing device 10 according to the present embodiment can be suitably applied to a place where it is necessary to seal an annular gap between a relatively rotating shaft 500 and a housing 600 in an automobile or various general-purpose machines. Further, in the sealing device 10 according to the present embodiment, the shaft 500 can be suitably used in a usage environment in which the shaft 500 is configured to rotate in the forward and reverse directions relative to the housing 600. However, the sealing device 10 according to the present embodiment can be applied even in a usage environment in which the shaft 500 rotates relative to the housing 600 in only one direction.

<Seal device>
The sealing device 10 according to this embodiment will be described in more detail. The sealing device 10 according to the present embodiment includes a first seal 100 as a resin seal and a second seal 200 as an annular member. The second seal 200 is composed of a reinforcing ring 210 made of metal or the like, and a seal body 220 made of a rubber-like elastic body integrally provided with the reinforcing ring 210. The reinforcing ring 210 has a cylindrical portion 211 and an inward flange portion 212 extending radially inward from the tip of the cylindrical portion 211. Further, the seal body 220 includes an outer peripheral seal portion 221 provided on the outer peripheral surface side of the cylindrical portion 211 of the reinforcing ring 210, and a dust strip 222 extending from the tip of the inward flange portion 212. When the sealing device 10 (second seal 200) is attached to the shaft hole (hole through which the shaft 500 is inserted) formed in the housing 600, the outer peripheral seal portion 221 is in close contact with the inner peripheral surface of the shaft hole to seal the housing 600. The sex is demonstrated. Further, the dust strip 222 is slidably provided with respect to the outer peripheral surface of the shaft 500. The dust strip 222 plays a role of suppressing foreign matter such as dust in the atmosphere from entering the sealing target region side (O). The second seal 200 can be obtained by molding the seal body 220 by insert molding using the reinforcing ring 210 as an insert component.

The first seal 100 as a resin seal is composed of a flat washer-shaped member. Polytetrafluoroethylene (PTFE) can be preferably applied as the material of the first seal 100. The outer peripheral end side of the first seal 100 is fixed to the second seal 200 as an annular member. More specifically, the outer peripheral surface of the first seal 100 is fitted to the inner peripheral surface of the reinforcing ring 210 in the second seal 200, so that the first seal 100 is fixed to the second seal 200.

The first seal 100 is formed on the outer peripheral surface of the shaft 500 in a state in which the inner peripheral end side is deformed so as to be curved toward the sealing target region side (O) by inserting the shaft 500 on the inner peripheral surface side thereof. It is configured to be in sliding contact (see FIG. 2). That is, the inner peripheral end side of the first seal 100 is configured to be deformed into a cylindrical shape by inserting the shaft 500. A pair of screw pump grooves 111 and 112 are provided in the region of the first seal 100 that slides on the outer peripheral surface of the shaft 500 (the region shown in the range X in FIG. 2). These pair of screw pump grooves 111 and 112 are on the sealing target region side (sealed target region side) in the region shown in the range X.
It is configured to extend from a position separated from the end of O) to the opposite side (A) (a position separated by Y in FIG. 2) so that the distance between the two becomes narrower toward the opposite side (A). Has been done. Although it is possible to adopt a configuration in which only one set of the pair of screw pump grooves 111 and 112 is provided, it is desirable to provide a plurality of sets at intervals in the circumferential direction. The dust strip 222 may have a slight gap with respect to the outer peripheral surface of the shaft 500.

<Advantages of the sealing device according to this embodiment>
According to the sealing device 10 according to the present embodiment, when the shaft 500 rotates in a positive direction relative to the housing 600, the shaft 500 tries to leak due to the screw pump effect of one of the pair of screw pump grooves 111 and 112. The fluid to be sealed can be returned to the area to be sealed (O). This point will be described with reference to FIG. FIG. 3 schematically shows how a fluid flows when the shaft 500 rotates in a positive direction relative to the housing 600. In FIG. 3, the arrow R indicates the direction of rotation of the shaft 500 with respect to the sealing device 10. Further, in the figure, the arrow S1 indicates the flow of the fluid to be sealed, which is about to leak from the region to be sealed (O) to the opposite side (A). As shown in the figure, the fluid to be sealed that is about to leak from the area to be sealed (O) to the opposite side (A) exerts the screw pump effect by the screw pump groove 111 of one of the pair of screw pump grooves 111 and 112. It is returned to the sealing target area side (O).

Further, when the shaft 500 rotates relative to the housing 600 in the reverse direction, the fluid to be sealed that is about to leak is sealed by the screw pump effect of the other screw pump groove 112 of the pair of screw pump grooves 111 and 112. Needless to say, it can be returned to the target area side (O). As described above, the screw pump effect can be exhibited in both the case where the shaft 500 rotates in the forward direction and the case where the shaft 500 rotates in the reverse direction with respect to the housing 600.

Therefore, in an environment where the relative rotation speed of the shaft 500 with respect to the housing 600 is high or it is difficult to improve the lubricity, the first seal 100, which is a resin seal, is slid on the shaft 500. Even if it is adopted, stable sealing performance can be exhibited.

When a plurality of pairs of screw pump grooves 111 and 112 are provided at intervals in the circumferential direction, the screw pump effect can be exhibited at a plurality of locations in the circumferential direction. Therefore, the sealing property can be further improved.

(Example 2)
FIG. 4 shows Example 2 of the present invention. In this embodiment, in the configuration of the sealing device shown in the first embodiment, a configuration in which a screw pump protrusion is provided instead of the screw pump groove will be described. Since other 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.

FIG. 4 is an explanatory diagram of the mechanism of the sealing device according to the second embodiment of the present invention. Note that FIG. 4A shows the state of the inner peripheral surface of the resin seal in a state where the sealing device is attached to the annular gap between the shaft and the housing. Further, FIG. 4B is a cross-sectional view of the resin seal in a state where the sealing device is attached to the annular gap between the shaft and the housing (as in the case of the first embodiment, AA in FIG. 2). (Corresponding to the cross section) is shown.

In the sealing device according to the present embodiment, only the configuration of the first seal 100A as the resin seal is different from the sealing device 10 shown in the first embodiment. Therefore, the description of the second seal 200 will be omitted. Further, since the sealed structure is the same as that of the first embodiment, the description thereof will be omitted.

The first seal 100A according to the present embodiment is also composed of flat washer-shaped members as in the case of the first embodiment. Further, as the material of the first seal 100A, polytetrafluoroethylene (PTFE) can be preferably applied. The first seal 100A is the same as in the case of the first embodiment in that the outer peripheral end side thereof is fixed to the second seal 200 as an annular member.

Further, in the first seal 100A, the outer peripheral surface of the shaft 500 is deformed so that the inner peripheral end side is curved toward the sealing target region side (O) by inserting the shaft 500 on the inner peripheral surface side thereof. It is the same as in the case of the first embodiment (see FIG. 2) in that it is configured to be slidably contacted with the above. Then, in the first seal 100A according to the present embodiment, in the region sliding on the outer peripheral surface of the shaft 500 (corresponding to the region shown in the range X in FIG. 2 as in the case of the first embodiment). A pair of screw pump protrusions 121 and 122 are provided. These pair of screw pump protrusions 121 and 122 are located on the opposite side (A) from the end of the sealing target region side (O) in the region shown in the range X (corresponding to a position separated by Y in FIG. 2). From, it is configured to extend so that the distance between them becomes narrower toward the opposite side (A). Although it is possible to adopt a configuration in which only one set of the pair of screw pump protrusions 121 and 122 is provided, it is desirable to provide a plurality of sets at intervals in the circumferential direction.

As described above, the same effect as in the case of the first embodiment can be obtained even in the sealing device provided with the first seal 100A according to the present embodiment. This point will be described more specifically with reference to FIG. FIG. 4 schematically shows how a fluid flows when the shaft 500 rotates in a positive direction relative to the housing 600. In FIG. 4, the arrow R indicates the direction of rotation of the shaft 500 with respect to the sealing device 10. Further, in the figure, the arrow S2 indicates the flow of the fluid to be sealed, which is about to leak from the region to be sealed (O) to the opposite side (A). As shown in the figure, the fluid to be sealed that is about to leak from the area to be sealed (O) to the opposite side (A) exerts the screw pump effect by the screw pump protrusion 121 of one of the pair of screw pump protrusions 121 and 122. It is returned to the sealing target area side (O).

Further, when the shaft 500 rotates relative to the housing 600 in the reverse direction, the fluid to be sealed that is about to leak is sealed by the screw pump effect of the other screw pump protrusion 122 of the pair of screw pump protrusions 121 and 122. Needless to say, it can be returned to the target area side (O). As described above, also in this embodiment, the screw pump effect can be exhibited in both the case where the shaft 500 rotates in the forward direction and the case where the shaft 500 rotates in the reverse direction with respect to the housing 600. Therefore, the same effect as in the case of the first embodiment can be obtained.

Here, the configuration of the sealing device including the resin seal (first seal) in the present invention is not limited to the configuration shown in the first embodiment, and various configurations can be adopted. In particular, various configurations can be adopted as the configuration for fixing the resin seal. Some examples are shown below.

(Example 3)
FIG. 5 shows Example 3 of the present invention. Since the basic configuration and operation are the same as those in the first embodiment, the same components will be 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 sealed structure according to the third embodiment of the present invention. FIG. 5 shows a cross section of each member cut along a surface including the central axis of the sealing device. Further, in FIG. 5, among the members constituting the sealing structure, only the arrangement positions of the shaft and the housing are shown by dotted lines so that the configuration of the inner peripheral surface of the sealing device can be understood.

The sealing device 10A according to the present embodiment includes a first seal 100A as a resin seal and a second seal 200A as an annular member. The second seal 200A is composed of a reinforcing ring 210 made of metal or the like, and a seal body 220A made of a rubber-like elastic body integrally provided with the reinforcing ring 210. Since the configuration of the reinforcing ring 210 is the same as that of the reinforcing ring 210 shown in the first embodiment, the description thereof will be omitted. Further, the seal body 220A includes an outer peripheral seal portion 221 provided on the outer peripheral surface side of the cylindrical portion 211 of the reinforcing ring 210. The seal body 220A according to the present embodiment is different from the case of the first embodiment only in that the dust strip is not provided.

Since the configuration of the first seal 100 as the resin seal is the same as that of the first embodiment, the description thereof will be omitted. In this embodiment as well, as in the case of the first embodiment, the outer peripheral surface of the first seal 100A is fitted to the inner peripheral surface of the reinforcing ring 210 in the second seal 200A, so that the first seal 100A is formed. It is fixed to the second seal 200A. Further, also in the first seal 100A according to the present embodiment, a state in which the inner peripheral end side is deformed so as to be curved toward the sealing target region side (O) by inserting the shaft 500 on the inner peripheral surface side thereof. It is configured to slidably contact the outer peripheral surface of the shaft 500. It is possible to adopt a configuration in which only one set of the pair of screw pump grooves 111 and 112 and the pair of screw pump grooves 111 and 112 are provided, but it is desirable to provide a plurality of sets at intervals in the circumferential direction. Is also as described in Example 1.

Needless to say, the sealing device 10A according to the present embodiment configured as described above also has the same effect as that of the first embodiment. Further, also in the sealing device 10A according to the present embodiment, as described in the second embodiment, a pair of screw pump protrusions 121 and 122 can be adopted instead of the pair of screw pump grooves 111 and 112.

(Example 4)
FIG. 6 shows Example 4 of the present invention. Since the basic configuration and operation are the same as those in the first embodiment, the same components will be designated by the same reference numerals, and the description thereof will be omitted as appropriate.

FIG. 6 is a schematic cross-sectional view of the sealed structure according to the fourth embodiment of the present invention. FIG. 6 shows a cross section of each member cut along a surface including the central axis of the sealing device. Further, in FIG. 6, among the members constituting the sealing structure, only the arrangement positions of the shaft and the housing are shown by dotted lines so that the configuration of the inner peripheral surface of the sealing device can be understood.

The sealing device 10B according to the present embodiment includes a first seal 100B as a resin seal and a fixed ring 200B as an annular member made of metal or the like. The fixed ring 200B has a cylindrical portion 201 and an inward flange portion 202 extending radially inward from the tip of the cylindrical portion 201. Further, also in this embodiment, the first seal 100B is composed of a flat washer-shaped member. As described in Example 1, polytetrafluoroethylene (PTFE) can be suitably applied as the material of the first seal 100B. The outer peripheral end side of the first seal 100B is fixed to the fixed ring 200B as an annular member. In the case of this embodiment, a part of the outer peripheral end side of the first seal 100B is sandwiched between the outer peripheral surface of the cylindrical portion 201 of the fixed ring 200B and the inner peripheral surface of the shaft hole of the housing 600. It is fixed to the fixed ring 200B.

Also in this embodiment, the shaft 500 of the first seal 100B is deformed so that the inner peripheral end side is curved toward the sealing target region side (O) by inserting the shaft 500 on the inner peripheral surface side thereof. It is configured to slidably contact the outer peripheral surface of the 500. And this first seal 1
A pair of screw pump grooves 111 and 112 are provided in the region of 00B that slides on the outer peripheral surface of the shaft 500. Since the configurations and working effects of the pair of screw pump grooves 111 and 112 are the same as in the case of the first embodiment, the description thereof will be omitted. Further, although it is possible to adopt a configuration in which only one set of the pair of screw pump grooves 111 and 112 is provided, it is desirable to provide a plurality of sets at intervals in the circumferential direction as described in the first embodiment. ..

Needless to say, the sealing device 10B according to the present embodiment configured as described above also has the same effect as that of the first embodiment. Further, also in the sealing device 10B according to the present embodiment, as described in the second embodiment, a pair of screw pump protrusions 121 and 122 can be adopted instead of the pair of screw pump grooves 111 and 112.

(Example 5)
FIG. 7 shows Example 5 of the present invention. Since the basic configuration and operation are the same as those in the first embodiment, the same components will be designated by the same reference numerals, and the description thereof will be omitted as appropriate.

FIG. 7 is a schematic cross-sectional view of the sealed structure according to the fifth embodiment of the present invention. FIG. 7 shows a cross section of each member cut along a surface including the central axis of the sealing device. Further, in FIG. 7, among the members constituting the sealing structure, only the arrangement positions of the shaft and the housing are shown by dotted lines so that the configuration of the inner peripheral surface of the sealing device can be understood.

The sealing device 10C according to the present embodiment is composed of a first seal 100C as a resin seal and a pair of fixed rings 200C (annular members) made of metal or the like. Each of the pair of fixed rings 200C has a cylindrical portion 205 and an inward flange portion 206 extending radially inward from the tip of the cylindrical portion 205. Further, also in this embodiment, the first seal 100C is composed of a flat washer-shaped member. As described in Example 1, polytetrafluoroethylene (PTFE) can be suitably applied as the material of the first seal 100C. The outer peripheral end side of the first seal 100C is fixed to a pair of fixed rings 200C. In the case of this embodiment, a part of the outer peripheral end side of the first seal 100C is sandwiched by the inward flange portions 206 of the pair of fixed rings 200C, so that the first seal 100C is fixed to the pair of fixed rings 200C.

Also in this embodiment, the shaft 500 of the first seal 100C is deformed so that the inner peripheral end side is curved toward the sealing target region side (O) by inserting the shaft 500 on the inner peripheral surface side thereof. It is configured to slidably contact the outer peripheral surface of the 500. A pair of screw pump grooves 111 and 112 are provided in the region of the first seal 100C that slides on the outer peripheral surface of the shaft 500. Since the configurations and working effects of the pair of screw pump grooves 111 and 112 are the same as in the case of the first embodiment, the description thereof will be omitted. Further, although it is possible to adopt a configuration in which only one set of the pair of screw pump grooves 111 and 112 is provided, it is desirable to provide a plurality of sets at intervals in the circumferential direction as described in the first embodiment. ..

Needless to say, the sealing device 10C according to the present embodiment configured as described above also has the same effect as that of the first embodiment. Further, also in the sealing device 10C according to the present embodiment, as described in the second embodiment, a pair of screw pump protrusions 121 and 122 can be adopted instead of the pair of screw pump grooves 111 and 112.

10,10A, 10B, 10BC Sealing device 100, 100A, 100B, 100C First seal (resin seal)
111,112 Screw pump groove 121,122 Screw pump protrusion 200,200A Second seal (annular member)
200B, 200C fixed ring (annular member)
201,205 Cylindrical part 202,206 Inward flange part 210 Reinforcing ring 211 Cylindrical part 212 Inward flange part 220, 220A Seal body 221 Outer peripheral seal part 222 Dustrip 500 Shaft 600 Housing

Claims (4)

A sealing device that seals an annular gap between a relatively rotating shaft and a housing.
A resin seal that slidably contacts the outer peripheral surface of the shaft in a state in which the inner peripheral end side is deformed so as to be curved toward the sealing target region side with the insertion of the shaft is provided.
In the region of the resin seal that slides on the outer peripheral surface of the shaft, each other is moved from a position distant from the end on the sealing target region side to the opposite side to the sealing target region side toward the opposite side. A sealing device provided with a pair of screw pump grooves or screw pump protrusions extending so as to be closely spaced. The sealing device according to claim 1, wherein a plurality of sets of the pair of screw pump grooves or screw pump protrusions are provided at intervals in the circumferential direction. The sealing device according to claim 1 or 2, wherein the resin seal is composed of a flat washer-shaped member. It comprises at least one annular member that is fixed to the shaft hole formed in the housing.
The sealing device according to claim 3, wherein the resin seal is fixed to the at least one annular member on the outer peripheral end side thereof.

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