JP2022161481A - sealing device - Google Patents

Abstract

To provide a sealing device for releasing a pressure accumulated in a sealing space while suppressing the leakage of fluid from the sealing space to the outside.SOLUTION: A sealing device 100 is provided for partitioning a space between a housing 300 provided with a shaft hole HLa and a shaft member 200 inserted into the shaft hole HLa into a first space SP1 and a second space SP2. The sealing device 100 includes an annular first seal part 110 for contacting an inner peripheral face 300ip of the housing 300, and an annular second seal part 120 for sliding on an outer peripheral face 200op of the shaft member 200. In a slide surface SLD which slides with the outer peripheral face 200op of the shaft member 200, the second seal part 120 has a spirally shaped spiral groove 120ss ranging from the first space SP1 to the second space SP2 and a pressure relief groove 120ds ranging from the first space SP1 to the second space SP2 and having a curve-shaped curved part. The pathway length of the pressure relief groove 120ds is smaller than the pathway length of the spiral groove 120ss.SELECTED DRAWING: Figure 1

Description

The present invention relates to sealing devices.

Conventionally, there has been proposed a sealing device for sealing a gap between an inner peripheral surface of a housing member provided with a shaft hole and an outer peripheral surface of a shaft member that is inserted into the shaft hole and rotates. For example, Patent Literature 1 describes a technique related to a sealing device in which a screw groove is provided on a surface that slides on the outer peripheral surface of a shaft (an example of a “shaft member”). In this type of sealing device, the pumping action is produced by the rotation of the shaft relative to the thread. The pumping action is, for example, the action of generating a force that pushes the fluid to be sealed back toward the inside of the machine (the side of the sealed space where the fluid is sealed). Therefore, in the sealing device provided with the thread groove, the pumping action prevents the fluid from leaking to the atmosphere.

JP-A-2001-165328

By the way, the pressure in the sealed space may become higher than the desired pressure due to the pumping action. In this case, even if the rotation of the shaft stops, the pressure in the sealed space is maintained higher than the pressure in the sealed space under normal conditions, which may adversely affect the sealed space and parts around the sealed space.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to release the pressure accumulated in the sealed space while suppressing leakage of the fluid in the sealed space to the outside.

In order to solve the above problems, a sealing device according to an aspect of the present invention provides a first space and a first space between a storage member provided with a shaft hole and a shaft member inserted into the shaft hole. The sealing device is divided into two spaces, and has an annular first portion that contacts the inner peripheral surface of the housing member and an annular second portion that slides on the outer peripheral surface of the shaft member, The second part has a spiral first groove extending from the first space to the second space, and a sliding surface that slides on the outer peripheral surface of the shaft member. A second groove spans the space and has a curvilinear curve, the path length of the second groove being less than the path length of the first groove.

It is a typical sectional view showing the state where the sealing device concerning an embodiment was equipped with the housing. FIG. 10 is a front view of the second seal portion when the sealing device is not attached to the housing, as seen from the +Z direction; It is a perspective view which shows an example of a spiral thread groove and a depressurization thread groove. FIG. 8 is a schematic cross-sectional view showing a state in which a sealing device according to Modification 1 is attached to a housing; FIG. 8 is a cross-sectional view of a second seal portion according to Modification 1; FIG. 11 is a schematic cross-sectional view showing a state in which a sealing device according to modification 2 is attached to a housing; FIG. 11 is a cross-sectional view of a second seal portion according to Modification 2; FIG. 11 is a schematic cross-sectional view showing a state in which a sealing device according to modification 3 is attached to a housing;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, in each drawing, the dimensions and scale of each part are appropriately different from the actual ones. In addition, since the embodiments described below are preferred specific examples of the present invention, they are subject to various technically preferable limitations. It is not limited to these forms unless stated otherwise.

[1. embodiment]
Embodiments of the present invention will be described below. First, an example of an outline of a sealing device 100 according to an embodiment will be described with reference to FIG. 1 .

FIG. 1 is a schematic cross-sectional view showing a state in which a sealing device 100 according to an embodiment is attached to a housing 300. FIG. 1 is a cross section of the sealing device 100 when the sealing device 100 is cut along a plane passing through the central axis AX of the shaft member 200 described later (when the sealing device 100 is cut along the line A1-A2 shown in FIG. 2). The figure is shown schematically.

In this embodiment, for convenience of explanation, a three-axis orthogonal coordinate system having mutually orthogonal X, Y, and Z axes is introduced. Hereinafter, the direction indicated by the X-axis arrow is referred to as the +X direction, and the direction opposite to the +X direction is referred to as the -X direction. The direction indicated by the Y-axis arrow is referred to as the +Y direction, and the direction opposite to the +Y direction is referred to as the -Y direction. The direction indicated by the Z-axis arrow is called the +Z direction, and the opposite direction to the +Z direction is called the -Z direction.

A sealing device 100 (an example of a “sealing device”) is used for a rotating device 1 (not shown in its entirety) including a rotating shaft member 200 . The rotating device 1 may be, for example, a component forming part of an automobile part, such as a pump for sending fluid such as oil or gas. Note that the rotating device 1 may be a component that constitutes a part of devices other than those related to automobiles.

In the example shown in FIG. 1, the rotary device 1 includes a housing 300, a shaft member 200 inserted into a shaft hole HLa provided in the housing 300, and an annular sealing device 100 mounted on an inner peripheral surface 300ip of the housing 300. and In this embodiment, the “annular shape” is a shape obtained by removing other closed regions existing inside the one closed region from one closed region when viewed from above. Here, "planar view" means observing an object from a specific direction. A "closed region" is, for example, a region surrounded by one or both of a curve and a line segment. In this embodiment, as an example, it is assumed that the sealing device 100 has an annular shape when viewed from above in the +Z direction.

In the sealing device 100, for example, a first space SP1 and a second space are formed between a housing 300 (an example of a “storage member”) provided with a shaft hole HLa and a shaft member 200 inserted into the shaft hole HLa. It is divided into SP2. In the present embodiment, as an example, it is assumed that the first space SP1 is filled with oil (an example of a “fluid”) and the atmosphere exists in the second space SP2. In this case, the sealing device 100 prevents foreign matter such as dust present in the atmosphere from entering the first space SP1 from the second space SP2, and prevents the oil filled in the first space SP1 from To prevent leakage from the first space SP1 to the second space SP2. Note that the fluid that fills the first space SP1 is not limited to oil.

For example, if the rotary device 1 is a component that constitutes a part of a pump, the sealing device 100 includes a gear chamber (for example, a It may be used to prevent the fluid sealed in the first space SP1 of 1) from leaking into the motor chamber where the motor is located (eg the second space SP2 in FIG. 1). The gear chamber is positioned, for example, between the pump chamber in which the pump is arranged and the motor chamber, and is sealed with oil, grease, etc. used as lubricants. For example, the pump chamber is sealed with gas or the like, and the motor chamber is in the atmosphere. Also, the gear chamber and the pump chamber are separated by, for example, a sealing device. The sealing device used to separate the gear chamber and the pump chamber may have a configuration different from that of the sealing device 100 shown in FIG. 1, or may have a configuration similar to that of the sealing device 100 shown in FIG.

In the rotating device 1 shown in FIG. 1, the housing 300 is, for example, a cylindrical structure. Further, the shaft hole HLa is a space existing inside the inner peripheral surface 300ip of the housing 300 . For example, the inner peripheral surface 300ip of the housing 300 is grasped as a circle when viewed from above in the +Z direction. Also, the shaft member 200 is, for example, a cylindrical structure inserted into the shaft hole HLa of the housing 300 . In the present embodiment, as an example, the central axis AX of the shaft member 200 extends along the Z-axis, and the shaft member 200 rotates in the rotation direction DR (clockwise) with the central axis AX as the rotation axis. Suppose.

The sealing device 100 includes, for example, an annular first seal portion 110 (an example of a “first portion”) that contacts the inner peripheral surface 300ip of the housing 300, and an annular second seal portion 110 that slides on the outer peripheral surface 200op of the shaft member 200. and a seal portion 120 (an example of a “second portion”).

The first seal portion 110 includes an elastic ring 112 made of a rubber-like elastic material (a rubber material or a synthetic resin material having rubber-like elasticity) such as fluororubber, acrylic rubber, and nitrile rubber; and a reinforcing ring 114 made of metal. The reinforcing ring 114 has a substantially L-shaped cross-sectional shape when cut along a plane passing through the central axis AX of the shaft member 200 . For example, the reinforcing ring 114 has a cylindrical portion 114cl and a flange portion 114fg protruding toward the shaft member 200 from the end of the cylindrical portion 114cl on the second space SP2 side. In the example shown in FIG. 1, the reinforcing ring 114 is covered with the elastic ring 112 except for a portion of the flange portion 114fg. The reinforcing ring 114 may have any structure as long as it can reinforce the elastic ring 112 , and may be partially covered with the elastic ring 112 or entirely covered with the elastic ring 112 .

The elastic ring 112 is formed by, for example, cross-linking (vulcanization) molding using a molding die. For example, the elastic ring 112 has an outer peripheral seal portion 112os covering the cylindrical portion 114cl of the reinforcing ring 114, a support portion 112sp covering a portion of the flange portion 114fg of the reinforcing ring 114, and a dust lip portion 112dl.

The outer peripheral seal portion 112 os seals the gap between the inner peripheral surface 300 ip of the housing 300 and the reinforcing ring 114 . For example, the outer peripheral seal portion 112os is adhered to the cylindrical portion 114cl of the reinforcing ring 114 with a predetermined interference with respect to the inner peripheral surface 300ip of the housing 300 .

The support portion 112sp has a connecting portion 112jo that partially covers the flange portion 114fg of the reinforcing ring 114, and a cylindrical portion 112cl in which the second seal portion 120 is fitted. The second seal portion 120 is connected to the surface of the connecting portion 112jo on the side of the first space SP1 and the inner peripheral surface of the cylindrical portion 112cl. A dust lip portion 112dl is provided at the end of the connecting portion 112jo on the shaft member 200 side.

The dust lip portion 112dl slides on the outer peripheral surface 200op of the shaft member 200 to prevent foreign matter such as dust from entering from the second space SP2 side. For example, the dust lip portion 112dl is formed from the shaft member 200 side end of the connecting portion 112jo so that the angle formed by the dust lip portion 112dl and the shaft member 200 is an obtuse angle on the second space SP2 side. It protrudes to the member 200 side.

The second seal portion 120 is made of a synthetic resin material such as PTFE (Poly Tetra Fluoro Ethylene). PTFE is a material that is excellent in wear resistance, fluid resistance, and heat resistance, and has a low coefficient of friction, and is also used as a solid lubricant. The second seal portion 120 may be made of a synthetic resin material other than PTFE.

When the sealing device 100 is not attached to the housing 300, that is, when the shaft member 200 is not inserted into the second seal portion 120, the second seal portion 120 moves in the +Z direction as shown in FIG. When viewed from above, it is grasped as a disk shape having a hole HLb in the center. The second seal portion 120 has a seal lip portion 120sl and a base end portion 120be connected to the first seal portion 110 . The seal lip portion 120sl is positioned, for example, between the center hole HLb and the base end portion 120be. That is, the base end portion 120be is located on the outer peripheral side of the seal lip portion 120sl.

As shown in FIG. 1, the base end portion 120be of the second seal portion 120 is fitted into the inner peripheral surface of the cylindrical portion 112cl provided in the support portion 112sp of the first seal portion 110 with a predetermined interference. . As a result, the base end portion 120be of the second seal portion 120 is connected to the connecting portion 112jo and the cylindrical portion 112cl of the first seal portion 110, and the second seal portion 120 is fixed to the first seal portion 110. FIG. The method of fixing the second seal portion 120 is not limited to connection by fitting into the cylindrical portion 112cl. For example, the base end portion 120be of the second seal portion 120 may be adhered to the connecting portion 112jo and the cylindrical portion 112cl of the first seal portion 110. As shown in FIG.

Further, the second seal portion 120 is curved such that the seal lip portion 120sl protrudes toward the first space SP1 when the shaft member 200 is inserted into the center hole HLb. Thereby, the seal lip portion 120sl slides on the outer peripheral surface 200op of the shaft member 200 . In the seal lip portion 120sl, a spiral groove 120ss (an example of a “first groove portion”) extending from the first space SP1 to the second space SP2 is provided on the sliding surface SLD that slides on the outer peripheral surface 200op of the shaft member 200, A depressurization groove 120ds (an example of a “second groove portion”) extending from the first space SP1 to the second space SP2 is provided.

The spiral groove 120ss is spirally provided so as to wrap around the outer peripheral surface 200op of the shaft member 200 . In this embodiment, as shown in FIG. 2, it is assumed that four spiral grooves 120ss are provided. For example, a route RT1 in FIG. 1 shows an example of a route of one spiral groove 120ss out of four spiral grooves 120ss. Of the route RT1 shown in FIG. The path of the spiral groove 120ss located in the +X direction is shown.

The spiral groove 120ss is provided so that rotation of the shaft member 200 produces a pumping action. For example, when the shaft member 200 rotates in the rotation direction DR (clockwise) with the central axis AX as the rotation axis, the flow ( A force that pushes the oil back toward the first space SP1 is generated. As a result, the oil filled in the first space SP1 can be prevented from leaking from the first space SP1 to the second space SP2.

Moreover, the depressurization groove 120ds has a curved portion, and is provided so that the path length is shorter than the path length of the spiral groove 120ss. In this embodiment, as shown in FIG. 2, it is assumed that 16 depressurization grooves 120ds are provided. For example, the route RT2 in FIG. 1 shows an example of the route of one depressurization groove 120ds out of the 16 depressurization grooves 120ds. A broken line portion of the route RT2 shown in FIG.

The depressurization groove 120ds is also provided so that the rotation of the shaft member 200 causes a pump action, similar to the spiral groove 120ss. For example, when the shaft member 200 rotates in the rotation direction DR (clockwise) with the central axis AX as the rotation axis, the oil existing in the pressure release grooves 120ds and the like is returned from the second space SP2 to the first space SP1 by a pump action. (A force that pushes the oil back toward the first space SP1) is generated.

It should be noted that, for example, the atmospheric air accumulated from the second space SP2 to the first space SP1 due to the pump action flows through the pressure release grooves 120ds and the spiral grooves 120ss (mainly, the pressure release grooves 120ds) when the shaft member 200 stops. Through the first space SP1 to the second space SP2. In the sealing device 100, compared to a configuration in which the depressurization grooves 120ds are not provided, the paths through which the gas escapes from the first space SP1 side to the second space SP2 side are increased, so the pressure accumulated in the first space SP1 ( gas) can be reduced. Furthermore, in the present embodiment, since the path length of the pressure release grooves 120ds is shorter than the path length of the spiral grooves 120ss, when the shaft member 200 stops or the rotation speed of the shaft member 200 becomes low, the first The pressure (gas) accumulated in one space SP1 can be released efficiently.

FIG. 2 is a front view of the second seal portion 120 when the sealing device 100 is not attached to the housing 300 as seen from the +Z direction. A dashed circle in FIG. 2 indicates a circle corresponding to the outer circumference of the shaft member 200 shown in FIG.

In the example shown in FIG. 2, each of the four spiral grooves 120ss is formed as a single spiral groove extending from the outer peripheral end to the inner peripheral end of the seal lip portion 120sl of the second seal portion 120. . Note that the four spiral grooves 120ss are arranged, for example, so that the respective ends on the outer peripheral side of the seal lip portion 120sl are arranged at equal intervals or approximately equal intervals along the outer periphery of the seal lip portion 120sl, and are equal to or substantially equal to each other. It is formed in almost the same spiral shape. Therefore, the four spiral grooves 120ss shown in FIG. 2 are arranged without crossing each other.

In addition, each of the 16 depressurization grooves 120ds is a curved groove having a path length shorter than the path length of the spiral groove 120ss from the outer peripheral end to the inner peripheral end of the seal lip portion 120sl of the second seal portion 120. formed. In the example shown in FIG. 2, the spiral groove 120ss makes almost two turns around the hole HLb, whereas the depressurization groove 120ds does not make one turn around the hole HLb. It reaches the inner peripheral end from the outer peripheral end of the seal lip portion 120sl.

For example, the extending direction of the route RT1 in the spiral groove 120ss is more parallel to the rotational direction DR of the shaft member 200 than the extending direction of the route RT2 in the depressurization groove 120ds. Therefore, the pump action caused by the spiral grooves 120ss is greater than the pump action caused by the pressure relief grooves 120ds. In other words, the pumping action caused by the depressurization grooves 120ds is smaller than the pumping action caused by the spiral grooves 120ss. Therefore, when the rotation speed of the shaft member 200 is lowered, there is a rotation speed at which the pump action caused by the spiral grooves 120ss occurs, but the pump action caused by the pressure release grooves 120ds does not occur. For example, in the present embodiment, when the rotation speed of the shaft member 200 becomes equal to or lower than the rotation speed at which the pumping action caused by the pressure release grooves 120ds does not occur, the pressure (gas) accumulated in the first space SP1 is released into the pressure release grooves 120ds. to the second space SP2 side (atmosphere side).

The depressurizing groove 120ds may be formed so as to make one or more rounds around the hole HLb if the amount of the spiral groove 120ss around the hole HLb is smaller than the amount of the spiral groove 120ss around the hole HLb. That is, the depressurization groove 120ds may be formed so as to make one turn or more around the hole HLb if the path length is shorter than the path length of the spiral groove 120ss.

In addition, each of the 16 depressurization grooves 120ds is arranged, for example, so that the respective ends on the outer peripheral side of the seal lip portion 120sl are equidistantly or substantially equidistantly along the outer periphery of the seal lip portion 120sl, They are formed in the same or substantially the same curved shape. Each of the 16 depressurization grooves 120ds intersects with each of the four spiral grooves 120ss.

Note that the number of spiral grooves 120ss is not limited to four. For example, the number of spiral grooves 120ss may be one or more and three or less. Alternatively, the number of spiral grooves 120ss may be five or more. Similarly, the number of pressure release grooves 120ds is not limited to 16. For example, the number of pressure release grooves 120ds may be 1 or more and 15 or less. Alternatively, the number of pressure release grooves 120ds may be 17 or more. In addition, in the example shown in FIG. 2, the pressure (gas) accumulated in the first space SP1 is efficiently released by increasing the number of the depressurization grooves 120ds more than the number of the spiral grooves 120ss. However, the number of pressure release grooves 120ds may be the same as the number of spiral grooves 120ss, or may be less than the number of spiral grooves 120ss. Further, for example, when the number of the spiral grooves 120ss and the number of the pressure relief grooves 120ds are respectively one, the pressure relief grooves 120ds may or may not intersect the spiral grooves 120ss. good too.

FIG. 3 is a perspective view showing an example of the spiral groove 120ss and the depressurization groove 120ds. 3 is an enlarged perspective view of the range AR1 in FIG. That is, FIG. 3 assumes that the sealing device 100 is not attached to the housing 300 . The shaded area in FIG. 3 indicates a plane whose position in the +Z direction is at the same position or substantially at the same position as the base end portion 120be of the second seal portion 120 . That is, when the sealing device 100 is not attached to the housing 300, the +Z direction position of the surface of the seal lip portion 120sl (the surface visible from the +Z direction) is +Z The same or nearly the same as the position of the direction. Therefore, when the sealing device 100 is not attached to the housing 300, the spiral groove 120ss and the depressurization groove 120ds are recessed in the -Z direction with respect to the base end portion 120be. In this embodiment, the depth D1 of the spiral groove 120ss and the depth D2 of the pressure relief groove 120ds are the same.

In this embodiment, by adjusting the depth D1 of the spiral groove 120ss, the depth D2 of the pressure relief groove 120ds, the number of the spiral grooves 120ss, the number of the pressure relief grooves 120ds, etc., the oil to be sealed is placed in the first space SP1. It is possible to release only the pressure (gas) to the second space SP2 without leaking from the second space SP2.

As described above, in the present embodiment, the sealing device 100 includes the annular first seal portion 110 that contacts the inner peripheral surface 300ip of the housing 300 and the annular second seal portion 120 that slides on the outer peripheral surface 200op of the shaft member 200. have In the second seal portion 120, a spiral groove 120ss extending from the first space SP1 to the second space SP2 and a spiral groove 120ss extending from the first space SP1 to the second space SP1 are provided on the sliding surface SLD that slides on the outer peripheral surface 200op of the shaft member 200. A depressurization groove 120ds is provided over SP2. The path length of the depressurization groove 120ds is shorter than the path length of the spiral groove 120ss. For example, the pressure relief groove 120ds intersects with the spiral groove 120ss.

Further, for example, the spiral groove 120ss is formed in a spiral shape so as to generate a flow that returns the fluid to be sealed from the second space SP2 to the first space SP1 when the shaft member 200 rotates. The depressurization groove 120ds has a curved portion so as to generate a flow that returns the fluid to be sealed from the second space SP2 to the first space SP1 when the shaft member 200 rotates. Accordingly, in the present embodiment, the fluid sealed in the first space SP1 can be prevented from leaking from the first space SP1 to the second space SP2.

Further, in the present embodiment, as described above, the second seal portion 120 is provided with the depressurization groove 120ds in addition to the spiral groove 120ss. Therefore, in the present embodiment, the pressure (gas) accumulated in the first space SP1 from the second space SP2 due to the pump action caused by the spiral groove 120ss or the like is released from the first space SP1 to the second space SP2. , compared to the configuration in which the depressurization grooves 120ds are not provided. Therefore, in this embodiment, the pressure (gas) accumulated in the first space SP1 can be reduced as compared with a configuration in which the depressurization grooves 120ds are not provided. In addition, in the present embodiment, since the path length of the depressurization grooves 120ds is shorter than the path length of the spiral grooves 120ss, when the shaft member 200 stops, or when the rotation speed of the shaft member 200 is low, the pump action of the spiral grooves 120ss is low, the pressure (gas) accumulated in the first space SP1 can be released efficiently.

Further, for example, when the number of the depressurization grooves 120ds is greater than the number of the spiral grooves 120ss, the pressure (gas) accumulated in the first space SP1 can be released efficiently.

As described above, in the present embodiment, the pressure accumulated in the sealed space can be released while suppressing leakage of the fluid in the sealed space such as the first space SP1 to the outside. As a result, in the present embodiment, when the shaft member 200 is stopped, the pressure in the sealed space can be prevented from being maintained higher than the pressure in the sealed space in the normal state, and the sealed space and the periphery of the sealed space can be prevented from being maintained. It is possible to reduce the adverse effect on the parts of

[2. Modification]
The embodiments illustrated above can be variously modified. Specific modification aspects that can be applied to the above-described embodiment are exemplified below. Two or more aspects arbitrarily selected from the following examples may be combined as long as they do not contradict each other.

[Modification 1]
In the above-described embodiment, the spiral groove 120ss and the depressurization groove 120ds when the sealing device 100 is not attached to the housing 300 exemplify a mode in which the base end portion 120be is recessed in the −Z direction. The invention is not limited to such embodiments. For example, when the sealing device 100 is not attached to the housing 300, the wall of the spiral groove 120ss and the wall of the depressurization groove 120ds protrude in the +Z direction with respect to the base end portion 120be as shown in FIG. good.

FIG. 4 is a schematic cross-sectional view showing a state in which a sealing device 100A according to Modification 1 is attached to a housing 300. As shown in FIG. 4 is a cross-sectional view of the sealing device 100A when the sealing device 100A is cut along a plane passing through the central axis AX of the shaft member 200 (when the sealing device 100A is cut along the line A1-A2 shown in FIG. 2). is schematically shown. Elements similar to those described in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

The sealing device 100A is similar to the sealing device 100 shown in FIG. 1 except that it has a second sealing portion 120A instead of the second sealing portion 120 shown in FIG. A second seal portion 120A according to Modification 1 will be described with reference to FIG.

FIG. 5 is a cross-sectional view of a second seal portion 120A according to Modification 1. As shown in FIG. 5 shows a cross-sectional view of the second seal portion 120A when the portion of the second seal portion 120A corresponding to the range AR1 shown in FIG. 2 is cut along the line A1-A2 shown in FIG. .

When the sealing device 100 is not attached to the housing 300, the surface M1 (the surface visible from the +Z direction) of the seal lip portion 120sl of the second seal portion 120A faces the surface M2 (the surface visible from the +Z direction) of the base end portion 120be. is located in the +Z direction. A spiral groove 120ss and a depressurization groove 120ds are provided on the surface M1 (the surface seen from the +Z direction) of the seal lip portion 120sl of the second seal portion 120A. That is, in the second seal portion 120A as well, the sliding surface SLD that slides on the outer peripheral surface 200op of the shaft member 200 is provided with the spiral groove 120ss and the depressurization groove 120ds. In Modified Example 1 shown in FIG. 5, when the sealing device 100 is not attached to the housing 300, the positions of the bottom surface of the spiral groove 120ss and the bottom surface of the depressurization groove 120ds in the +Z direction are the base end portion of the second seal portion 120A. It is the same or almost the same as the position in the +Z direction of the surface M2 of 120be (the surface seen from the +Z direction).

Also in Modification 1, effects similar to those of the above-described embodiment can be obtained. For example, in Modification 1 as well, the pressure accumulated in the sealed space can be released while suppressing leakage of the fluid in the sealed space such as the first space SP1 to the outside.

[Modification 2]
In the above-described embodiment and modification 1, the depth D1 of the spiral groove 120ss and the depth D2 of the pressure release groove 120ds are the same as each other, but the present invention is limited to such an aspect. is not. For example, the depth D2 of the depressurization groove 120ds with respect to the sliding surface SLD may be different from the depth D1 of the spiral groove 120ss with respect to the sliding surface SLD.

FIG. 6 is a schematic cross-sectional view showing a state in which a sealing device 100B according to Modification 2 is attached to a housing 300. As shown in FIG. 6 is a cross-sectional view of the sealing device 100B when the sealing device 100B is cut along a plane passing through the central axis AX of the shaft member 200 (when the sealing device 100B is cut along the line A1-A2 shown in FIG. 2). is schematically shown. Elements similar to those described in FIGS. 1 to 5 are denoted by the same reference numerals, and detailed description thereof is omitted.

The sealing device 100B is similar to the sealing device 100 shown in FIG. 1 except that it has a second sealing portion 120B instead of the second sealing portion 120 shown in FIG. A second seal portion 120B according to Modification 2 will be described with reference to FIG.

FIG. 7 is a cross-sectional view of a second seal portion 120B according to Modification 2. As shown in FIG. 7 shows a cross-sectional view of the second seal portion 120B in the case where the portion of the second seal portion 120B corresponding to the range AR1 shown in FIG. 2 is cut along the line A1-A2 shown in FIG. . Elements similar to those described in FIGS. 1 to 5 are denoted by the same reference numerals, and detailed description thereof is omitted.

The second seal portion 120B shown in FIG. 7 is the same as the second seal portion 120 shown in FIGS. 1 to 3 except for the depth D2 of the depressurization groove 120ds. The second seal portion 120B is formed such that the depth D2 of the pressure relief groove 120ds with respect to the sliding surface SLD is shallower than the depth D1 of the spiral groove 120ss with respect to the sliding surface SLD.

Also in Modification 2, it is possible to obtain the same effect as the embodiment described above. For example, even in Modification 2, it is possible to release the pressure accumulated in the sealed space while suppressing leakage of the fluid in the sealed space such as the first space SP1 to the outside. Further, in Modification 2 shown in FIG. 7, the depth D2 of the depressurization groove 120ds with respect to the sliding surface SLD is shallower than the depth D1 of the spiral groove 120ss with respect to the sliding surface SLD. Therefore, in the modification 2 shown in FIG. 7, the depth D2 of the depressurization groove 120ds with respect to the sliding surface SLD is the same as the depth D1 of the spiral groove 120ss with respect to the sliding surface SLD. can be suppressed from leaking into the second space SP2.

The depth D2 of the depressurization groove 120ds with respect to the sliding surface SLD may be deeper than the depth D1 of the spiral groove 120ss with respect to the sliding surface SLD. In Modification 2 as well, by adjusting the depth D1 of the spiral groove 120ss, the depth D2 of the pressure release groove 120ds, the number of the spiral grooves 120ss, the number of the pressure release grooves 120ds, etc., the fluid such as oil to be sealed can be removed. It is possible to release only the pressure (gas) to the second space SP2 without leaking from the first space SP1.

[Modification 3]
In the above-described embodiment, modified example 1, and modified example 2, the base end portion 120be of each of the second seal portions 120, 120A, and 120B is the inner circumference of the cylindrical portion 112cl provided on the support portion 112sp of the first seal portion 110. Although the aspect of fitting into the surface has been exemplified, the present invention is not limited to such an aspect. For example, the base end portion 120be of each of the second seal portions 120, 120A, and 120B may be fitted into the inner peripheral surface of the cylindrical portion 114cl of the reinforcing ring 114 of the first seal portion 110, as shown in FIG. .

FIG. 8 is a schematic cross-sectional view showing a state in which a sealing device 100C according to Modification 3 is attached to a housing 300. As shown in FIG. 8 is a cross-sectional view of the sealing device 100C when the sealing device 100C is cut along a plane passing through the central axis AX of the shaft member 200 (when the sealing device 100C is cut along the line A1-A2 shown in FIG. 2). is schematically shown. Elements similar to those described in FIGS. 1 to 7 are denoted by the same reference numerals, and detailed description thereof is omitted.

The sealing device 100C has a first seal portion 110C instead of the first seal portion 110 shown in FIG. 1, and a second seal portion 120C instead of the second seal portion 120 shown in FIG. .

The first seal portion 110C is similar to the first seal portion 110 shown in FIG. 1 except that it has an elastic ring 112C instead of the elastic ring 112 shown in FIG. The main difference between the elastic ring 112C and the elastic ring 112 shown in FIG. 1 is that the elastic ring 112C has a support portion 112Csp instead of the support portion 112sp. The main difference between the supporting portion 112Csp and the supporting portion 112sp shown in FIG. 1 is that the cylindrical portion 112cl shown in FIG. 1 is not provided in the supporting portion 112Csp.

Except that the second seal portion 120C has a base end portion 120Cbe instead of the base end portion 120be shown in FIG. This is the same as the second seal portion 120 shown in FIG. That is, in the sealing device 100C, the base end portion 120Cbe of the second seal portion 120C is fitted into the inner peripheral surface of the cylindrical portion 114cl of the reinforcing ring 114 of the first seal portion 110C with a predetermined interference. As a result, the base end portion 120Cbe of the second seal portion 120C is connected to the support portion 112Csp of the first seal portion 110C and the cylindrical portion 114cl of the reinforcing ring 114, and the second seal portion 120C is fixed to the first seal portion 110C. be done. The method of fixing the second seal portion 120C is not limited to connection by fitting into the cylindrical portion 114cl. For example, the base end portion 120Cbe of the second seal portion 120C may be adhered to the support portion 112Csp of the first seal portion 110 and the cylindrical portion 114cl of the reinforcing ring 114 .

Also in Modification 3, the same effect as the embodiment described above can be obtained. For example, in Modification 3 as well, the pressure accumulated in the sealed space can be released while suppressing leakage of the fluid in the sealed space such as the first space SP1 to the outside.

100, 100A, 100B, 100C... sealing device, 110, 110C... first seal portion, 112, 112C... elastic ring, 112cl... cylindrical portion, 112dl... dust lip portion, 112jo... connecting portion, 112os... outer peripheral seal portion, 112sp , 112Csp... Support portion 114... Reinforcement ring 114cl... Cylindrical part 114fg... Flange part 120, 120A, 120B, 120C... Second seal part 120be, 120Cbe... Base end part 120ds... Depression groove, 120sl... Seal lip portion, 120ss... Spiral groove, 200... Shaft member, 200op... Outer peripheral surface, 300... Housing, 300ip... Inner peripheral surface, AX... Central axis, HLa... Shaft hole, HLb... Hole, SLD... Sliding surface, SP1 ... first space, SP2 ... second space.

Claims (5)

A sealing device that divides a space between a storage member provided with a shaft hole and a shaft member inserted into the shaft hole into a first space and a second space,
an annular first portion that contacts the inner peripheral surface of the storage member;
an annular second portion that slides on the outer peripheral surface of the shaft member;
The second part includes
On the outer peripheral surface of the shaft member and the sliding surface that slides,
a helical first groove extending from the first space to the second space;
a second groove extending from the first space to the second space and having a curved curved portion;
the path length of the second groove is shorter than the path length of the first groove;
A sealing device characterized by: The second groove crosses the first groove,
The sealing device according to claim 1, characterized in that: The depth from the sliding surface of the second groove is shallower than the depth from the sliding surface of the first groove,
The sealing device according to claim 1 or 2, characterized in that: The number of the second grooves is greater than the number of the first grooves,
The sealing device according to any one of claims 1 to 3, characterized in that: the first space is filled with a fluid to be sealed, and the second space contains gas;
The first groove generates a flow that returns the fluid to be sealed from the second space to the first space when the shaft member rotates,
The second groove generates a flow that returns the fluid to be sealed from the second space to the first space when the shaft member rotates.
The sealing device according to any one of claims 1 to 4, characterized in that:

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