Sealing device

Abstract

The present invention relates to a sealing device that can suppress leakage of fluid in a sealed space to the outside and release pressure accumulated in the sealed space. The sealing device (100) is a sealing device (100) that divides the space between a housing (300) provided with an axial hole (HLa) and an axial component (200) inserted into the axial hole (HLa) into a first space (SP1) and a second space (SP2). The sealing device (100) includes an annular first sealing portion (110) in contact with the inner peripheral surface (300ip) of the housing (300) and an annular second sealing portion (120) that slides on the outer peripheral surface (200op) of the axial component (200). On the second sealing portion (120), a spiral groove (120ss) extending from the first space (SP1) to the second space (SP2) and having a spiral shape and a pressure relief groove (120ds) extending from the first space (SP1) to the second space (SP2) and having a curved portion are provided on a sliding surface (SLD) that slides with the outer peripheral surface (200op) of the shaft component (200). The path length of the pressure relief groove (120ds) is shorter than the path length of the spiral groove (120ss).

Description

Technical Field

[0001] The present invention relates to a sealing device. Background Art

[0002] In the past, a sealing device has been proposed that seals the gap between the inner circumference of a receiving component provided with an axial hole and the outer circumference of an axial component that is inserted into the axial hole and rotates. For example, Patent Document 1 describes a technology related to a sealing device in which a threaded groove is provided on a surface that slides with the outer circumference of a shaft (an example of a "shaft component"). In this sealing device, a pumping action is generated by the rotation of the shaft relative to the threaded groove. The pumping action is, for example, the action of generating a force that pushes the fluid of the sealed object back to the inside of the machine (the sealed space side of the sealed fluid). Therefore, in a sealing device provided with a threaded groove, the fluid is prevented from leaking to the atmosphere by the pumping action.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2001-165328 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] However, due to the pump action, the pressure in the sealed space sometimes becomes higher than the desired pressure. In this case, even if the rotation of the shaft stops, the pressure in the sealed space remains higher than the normal pressure in the sealed space, which may have an adverse effect on the sealed space and the components around the sealed space.

[0008] 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.

[0009] Means used to solve problems

[0010] In order to solve the above problems, a sealing device involved in one embodiment of the present invention divides the space between a storage component provided with an axial hole and an axial component inserted into the axial hole into a first space and a second space, and the sealing device comprises: an annular first part, which contacts the inner peripheral surface of the storage component; and an annular second part, which slides on the outer peripheral surface of the axial component, and in the second part, a sliding surface sliding with the outer peripheral surface of the axial component is provided with: a first groove portion, which extends from the first space to the second space and is spiral; and a second groove portion, which extends from the first space to the second space and has a curved portion, and the path length of the second groove portion is shorter than the path length of the first groove portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic cross-sectional view showing a state where the sealing device according to the embodiment is attached to a housing.

[0012] Figure 2 This is a front view of the second sealing portion when the sealing device is not mounted on the housing, as viewed from the +Z direction.

[0013] Figure 3 This is a perspective view showing an example of a spiral thread groove and a pressure relief thread groove.

[0014] Figure 4 This is a schematic cross-sectional view showing a state in which the sealing device according to Modification 1 is attached to a housing.

[0015] Figure 5 This is a cross-sectional view of the second sealing portion according to Modification 1.

[0016] Figure 6 This is a schematic cross-sectional view showing a state in which the sealing device according to Modification 2 is attached to a housing.

[0017] Figure 7 This is a cross-sectional view of the second sealing portion according to Modification 2.

[0018] Figure 8 This is a schematic cross-sectional view showing a state in which the sealing device according to Modification 3 is attached to a housing. DETAILED DESCRIPTION

[0019] The following describes embodiments of the present invention with reference to the accompanying drawings. However, in the drawings, the dimensions and scales of the various components may differ from the actual dimensions and scales as appropriate. Furthermore, the embodiments described below are preferred specific examples of the present invention and therefore include various technically preferred limitations. However, unless otherwise specified in the following description, the scope of the present invention is not limited to these embodiments.

[0020] (1. Implementation Method)

[0021] Hereinafter, the embodiments of the present invention will be described. Figure 1 An example of a schematic configuration of the sealing device 100 according to the embodiment will be described.

[0022] Figure 1 : is a schematic cross-sectional view showing a state where the sealing device 100 according to the embodiment is mounted on the housing 300. Figure 1 The diagram schematically shows the situation when the sealing device 100 is cut by a plane passing through the central axis AX of the shaft member 200 described later (using the Figure 2 The cross-sectional view of the sealing device 100 is shown when the sealing device 100 is cut along the line A1-A2.

[0023] In this embodiment, for ease of explanation, a three-axis orthogonal coordinate system is introduced, comprising mutually orthogonal X-axis, Y-axis, and Z-axis. Hereinafter, the direction indicated by the arrow of the X-axis 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 arrow of the Y-axis is referred to as the +Y direction, and the direction opposite to the +Y direction is referred to as the -Y direction. Furthermore, the direction indicated by the arrow of the Z-axis is referred to as the +Z direction, and the direction opposite to the +Z direction is referred to as the -Z direction.

[0024] A sealing device 100 (an example of a "sealing device") is used in a rotating machine 1 (not shown in its entirety) that includes a rotating shaft member 200. The rotating machine 1 may be, for example, a component that forms part of an automotive component, such as a pump for conveying fluids such as oil or gas. Furthermore, the rotating machine 1 may also be a component that forms part of equipment other than automotive-related equipment.

[0025] exist Figure 1 In the example shown, the rotating device 1 includes: a housing 300; a shaft member 200, which is inserted into the shaft hole HLa provided in the housing 300; and an annular sealing device 100, which is mounted on the inner peripheral surface 300ip of the housing 300. In addition, in the present embodiment, "annular" refers to a shape obtained by removing other closed areas existing inside a closed area from one closed area when viewed from above. Here, "viewed from above" refers to observing an object from a specific direction. In addition, a "closed area" is, for example, an area surrounded by one or both of a curve and a line segment. In the present embodiment, as an example, it is assumed that the sealing device 100 has an annular shape when viewed from above in the +Z direction.

[0026] The sealing device 100, for example, divides the space between a housing 300 (an example of a "housing component") having an axial hole HLa and a shaft member 200 inserted into the axial hole HLa into a first space SP1 and a second space SP2. In this embodiment, as an example, a scenario is assumed in which the first space SP1 is filled with oil (an example of a "fluid") and the second space SP2 contains air. In this scenario, the sealing device 100 prevents foreign matter, such as dust in the atmosphere, from entering the first space SP1 from the second space SP2, and also prevents the oil filling the first space SP1 from leaking from the first space SP1 into the second space SP2. The fluid filling the first space SP1 is not limited to oil.

[0027] For example, when the rotating device 1 is a component constituting a part of a pump, the sealing device 100 can also be used to prevent the seal from being formed in a gear chamber (for example, Figure 1 The fluid in the first space SP1) flows to the motor chamber (for example, Figure 1The second space SP2) of the gear chamber is provided with a gear for transmitting the power (rotation) of the shaft member 200 rotated by the motor. The gear chamber is located between, for example, a pump chamber provided with a pump and a motor chamber, and is sealed with oil and grease used as lubricants. In addition, for example, gas is sealed in the pump chamber, and the motor chamber contains atmosphere. In addition, the gear chamber and the pump chamber are divided, for example, by a sealing device. In addition, the sealing device for dividing the gear chamber and the pump chamber may be a sealing device that is connected to the gear chamber. Figure 1 The sealing device 100 shown may have a different structure than the one shown in FIG. Figure 1 The sealing device 100 shown has the same structure.

[0028] exist Figure 1 In the rotating device 1 shown, the housing 300 is, for example, a cylindrical structure. In addition, the axial hole HLa is a space existing inside the inner peripheral surface 300ip of the housing 300. For example, when viewed from the +Z direction, the inner peripheral surface 300ip of the housing 300 is understood to be a circle. In addition, the shaft component 200 is, for example, a cylindrical structure inserted into the axial hole HLa of the housing 300. In addition, in this embodiment, as an example, it is assumed that the central axis AX of the shaft component 200 extends along the Z axis, and the shaft component 200 rotates in the rotation direction DR (clockwise direction) with the central axis AX as the rotation axis.

[0029] The sealing device 100 includes, for example, an annular first sealing portion 110 (an example of a “first portion”) that contacts the inner peripheral surface 300ip of the housing 300 and an annular second sealing portion 120 (an example of a “second portion”) that slides on the outer peripheral surface 200op of the shaft member 200.

[0030] The first sealing portion 110 includes: an elastic ring 112 formed of a rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity) such as fluororubber, acrylic rubber and nitrile rubber; and a metal reinforcement ring 114 for reinforcing the elastic ring 112. The reinforcement ring 114 has a substantially L-shaped cross-sectional shape when cut along a plane passing through the central axis AX of the shaft component 200. For example, the reinforcement ring 114 includes: a cylindrical portion 114cl; and a flange portion 114fg protruding from the end of the cylindrical portion 114cl on the second space SP2 side toward the shaft component 200. Figure 1 In the example shown, the reinforcement ring 114 is covered by the elastic ring 112 except for a portion of the flange portion 114fg. The reinforcement ring 114 may be partially or entirely covered by the elastic ring 112, as long as it can reinforce the elastic ring 112.

[0031] The elastic ring 112 is formed, for example, by crosslinking (vulcanization) molding using a molding die. For example, the elastic ring 112 includes an outer peripheral sealing portion 112os covering the cylindrical portion 114cl of the reinforcement ring 114; a supporting portion 112sp covering a portion of the flange portion 114fg of the reinforcement ring 114; and a dustproof lip 112dl.

[0032] The outer peripheral seal portion 112os seals the gap between the inner peripheral surface 300ip of the housing 300 and the reinforcement ring 114. For example, the outer peripheral seal portion 112os has a predetermined interference fit with the inner peripheral surface 300ip of the housing 300 and is bonded to the cylindrical portion 114c1 of the reinforcement ring 114.

[0033] The support portion 112sp includes a connecting portion 112jo that covers a portion of the flange portion 114fg of the reinforcement ring 114, and a cylindrical portion 112cl into which the second seal 120 is inserted. The second seal 120 connects the surface of the connecting portion 112jo facing the first space SP1 and the inner circumferential surface of the cylindrical portion 112cl. A dust lip 112dl is provided at the end of the connecting portion 112jo facing the shaft member 200.

[0034] The dustproof lip 112d1 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 dustproof lip 112d1 protrudes from the end of the connecting portion 112jo on the shaft member 200 side toward the shaft member 200 so that the angle formed between the dustproof lip 112d1 and the shaft member 200 on the second space SP2 side is an obtuse angle.

[0035] Second sealing portion 120 is formed from a synthetic resin material such as PTFE (Poly Tetra Fluoro Ethylene). PTFE has excellent wear resistance, fluid resistance, and heat resistance, a low coefficient of friction, and can also be used as a solid lubricant. Alternatively, second sealing portion 120 may be formed from a synthetic resin material other than PTFE.

[0036] The second sealing portion 120 is in a state where the sealing device 100 is not mounted on the housing 300, that is, when the shaft member 200 is not inserted into the second sealing portion 120, as described later. Figure 2 As shown, when viewed from above in the +Z direction, the second seal portion 120 can be understood as having a disk shape with a hole HLb at its center. The second seal portion 120 includes a sealing lip 120sl and a base end 120be connected to the first seal portion 110. The sealing lip 120sl is positioned, for example, between the central hole HLb and the base end 120be. Specifically, the base end 120be is positioned further outward from the sealing lip 120sl.

[0037] like Figure 1As shown, the base end portion 120be of the second sealing portion 120 is embedded in the inner circumferential surface of the cylindrical portion 112cl provided in the support portion 112sp of the first sealing portion 110 with a predetermined interference fit. As a result, the base end portion 120be of the second sealing portion 120 is connected to the connecting portion 112jo and the cylindrical portion 112cl of the first sealing portion 110, and the second sealing portion 120 is fixed to the first sealing portion 110. Furthermore, the method for fixing the second sealing portion 120 is not limited to connection by embedding it in the cylindrical portion 112cl. For example, the base end portion 120be of the second sealing portion 120 may also be bonded to the connecting portion 112jo and the cylindrical portion 112cl of the first sealing portion 110.

[0038] Furthermore, when the shaft member 200 is inserted into the central hole HLb, the second seal portion 120 is curved so that the sealing lip portion 120sl protrudes toward the first space SP1. This allows the sealing lip portion 120sl to slide on the outer circumferential surface 200op of the shaft member 200. Furthermore, the sealing lip portion 120sl has a spiral groove 120ss (an example of a "first groove") extending from the first space SP1 to the second space SP2, and a pressure relief groove 120ds (an example of a "second groove") extending from the first space SP1 to the second space SP2, provided on its sliding surface SLD against the outer circumferential surface 200op of the shaft member 200.

[0039] The spiral groove 120ss is provided in a spiral shape in a manner wound around the outer peripheral surface 200op of the shaft member 200. In this embodiment, as shown in FIG. Figure 2 As shown, it is assumed that there are four spiral grooves 120ss. For example, Figure 1 The path RT1 shows an example of the path of one of the four spiral grooves 120ss. Figure 1 In the illustrated path RT1 , the dotted line portion indicates the path of the spiral groove 120ss located in the −X direction relative to the shaft member 200 , and the two-dot chain line portion indicates the path of the spiral groove 120ss located in the +X direction relative to the shaft member 200 .

[0040] The spiral groove 120ss is configured to generate a pumping action through the rotation of the shaft member 200. For example, when the shaft member 200 rotates in the rotational direction DR (clockwise) about the central axis AX, the pumping action generates a flow of oil in the spiral groove 120ss and the like from the second space SP2 back to the first space SP1 (a force pushing the oil back toward the first space SP1). This prevents the oil filling the first space SP1 from leaking from the first space SP1 into the second space SP2.

[0041] In addition, the pressure relief groove 120ds has a curved portion and is provided in a manner such that the path length is shorter than the path length of the spiral groove 120ss. Figure 2 As shown, it is assumed that 16 pressure relief grooves 120ds are provided. For example, Figure 1 The path RT2 shows an example of the path of one of the 16 pressure relief grooves 120ds. Figure 1 In the illustrated path RT2 , the portion indicated by the dotted line represents the path of the pressure relief groove 120 ds located in the −X direction with respect to the shaft member 200 .

[0042] Similar to the spiral groove 120ss, the pressure relief groove 120ds is also provided so as to generate a pumping action by the rotation of the shaft member 200. For example, when the shaft member 200 rotates in the rotation direction DR (clockwise) about the central axis AX, the pumping action generates a flow of oil in the pressure relief groove 120ds and the like from the second space SP2 back to the first space SP1 (a force pushing the oil back toward the first space SP1).

[0043] Furthermore, for example, atmospheric air accumulated in the first space SP1 from the second space SP2 by the pumping action is released from the first space SP1 to the second space SP2 via the pressure relief groove 120ds and the spiral groove 120ss (primarily the pressure relief groove 120ds) when the shaft member 200 stops. In the sealing device 100, compared to a configuration without the pressure relief groove 120ds, the path for gas to escape from the first space SP1 to the second space SP2 is increased, thereby reducing the pressure (gas) accumulated in the first space SP1. Furthermore, in this embodiment, since the path length of the pressure relief groove 120ds is shorter than that of the spiral groove 120ss, the pressure (gas) accumulated in the first space SP1 can be efficiently released when the shaft member 200 stops or when the shaft member 200 rotates at a low speed.

[0044] Figure 2 This is a front view of the second sealing portion 120 when the sealing device 100 is not attached to the housing 300 , as viewed from the +Z direction. Figure 2 The dotted circle represents Figure 1 The outer circumference of the shaft member 200 shown corresponds to a circle.

[0045] exist Figure 2 In the example shown, the four spiral grooves 120ss are formed as a single spiral groove from the outer peripheral end to the inner peripheral end of the sealing lip 120sl of the second sealing portion 120. Furthermore, the four spiral grooves 120ss are arranged, for example, with their respective ends on the outer peripheral side of the sealing lip 120sl spaced at equal or substantially equal intervals along the outer periphery of the sealing lip 120sl, forming the same or substantially the same spiral shape. Figure 2 The four spiral grooves 120ss shown are arranged so as not to intersect with each other.

[0046] Furthermore, the 16 pressure relief grooves 120ds are formed from the outer peripheral end to the inner peripheral end of the sealing lip 120sl of the second sealing portion 120 as curved grooves having a path length shorter than that of the spiral groove 120ss. Figure 2 In the illustrated example, the spiral groove 120ss surrounds the hole HLb approximately twice, whereas the pressure relief groove 120ds does not surround the hole HLb but extends from the outer peripheral end to the inner peripheral end of the seal lip 120s1 of the second seal portion 120 .

[0047] For example, the direction in which the path RT1 in the spiral groove 120ss extends is closer to parallel with the rotational direction DR of the shaft member 200 than the direction in which the path RT2 in the pressure relief groove 120ds extends. Therefore, the pumping action caused by the spiral groove 120ss is greater than the pumping action caused by the pressure relief groove 120ds. In other words, the pumping action caused by the pressure relief groove 120ds is smaller than the pumping action caused by the spiral groove 120ss. Therefore, if the rotational speed of the shaft member 200 is reduced, there is a rotational speed at which the pumping action caused by the spiral groove 120ss is generated, but the pumping action caused by the pressure relief groove 120ds is not. For example, in this embodiment, if the rotational speed of the shaft member 200 is lower than the rotational speed at which the pumping action caused by the pressure relief groove 120ds is not generated, the pressure (gas) accumulated in the first space SP1 can be released from the pressure relief groove 120ds to the second space SP2 (toward the atmosphere).

[0048] Alternatively, the pressure relief groove 120ds may be formed so as to extend around the hole HLb more than once if the amount around the hole HLb is less than the amount around the hole HLb of the spiral groove 120ss. In other words, the pressure relief groove 120ds may be formed so as to extend around the hole HLb more than once if the path length is shorter than the path length of the spiral groove 120ss.

[0049] The sixteen pressure relief grooves 120ds are arranged, for example, at equal or substantially equal intervals along the outer periphery of the sealing lip 120sl, with their respective ends on the outer periphery thereof forming the same or substantially the same curved lines. Furthermore, the sixteen pressure relief grooves 120ds intersect with each of the four spiral grooves 120ss.

[0050] In addition, the number of spiral grooves 120ss is not limited to 4. For example, the number of spiral grooves 120ss may be more than 1 and less than 3. Alternatively, the number of spiral grooves 120ss may be more than 5. Similarly, the number of pressure relief grooves 120ds is not limited to 16. For example, the number of pressure relief grooves 120ds may be more than 1 and less than 15. Alternatively, the number of pressure relief grooves 120ds may be more than 17. In addition, Figure 2 In the example shown, by having a greater number of pressure relief grooves 120ds than spiral grooves 120ss, the pressure (gas) accumulated in the first space SP1 is efficiently released. However, the number of pressure relief grooves 120ds may be the same as or less than the number of spiral grooves 120ss. Furthermore, for example, if the number of spiral grooves 120ss and the number of pressure relief grooves 120ds are both one, the pressure relief groove 120ds may or may not intersect with the spiral groove 120ss.

[0051] Figure 3 120ss and the pressure relief groove 120ds. Figure 3 It will Figure 2 The enlarged stereogram of the range AR1 in FIG. Figure 3 In FIG. 1 , it is assumed that the sealing device 100 is not mounted on the housing 300 . Figure 3 The shading indicates a surface whose position in the +Z direction is the same as, or approximately the same as, the position of the base end portion 120be of the second sealing portion 120. Specifically, when the sealing device 100 is not mounted on the housing 300, the +Z position of the surface of the sealing lip 120sl (the surface viewed from the +Z direction) is the same as, or approximately the same as, the +Z position of the surface of the base end portion 120be (the surface viewed from the +Z direction). Therefore, when the sealing device 100 is not mounted on the housing 300, the spiral groove 120ss and the pressure relief groove 120ds are recessed in the -Z direction relative 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.

[0052] 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 spiral grooves 120ss, and the number of pressure relief grooves 120ds, etc., the oil to be sealed does not leak from the first space SP1 and only the pressure (gas) can be released to the second space SP2.

[0053] As described above, in this embodiment, the sealing device 100 includes an annular first sealing portion 110 that contacts the inner circumferential surface 300ip of the housing 300, and an annular second sealing portion 120 that slides on the outer circumferential surface 200op of the shaft member 200. Furthermore, the sliding surface SLD of the second sealing portion 120 that slides on the outer circumferential surface 200op of the shaft member 200 includes a spiral groove 120ss extending from the first space SP1 to the second space SP2, and a pressure relief groove 120ds extending from the first space SP1 to the second space SP2. The path length of the pressure relief groove 120ds is shorter than that of the spiral groove 120ss. For example, the pressure relief groove 120ds intersects with the spiral groove 120ss.

[0054] For example, the spiral groove 120ss is formed in a spiral shape to generate a flow of the sealed fluid from the second space SP2 back to the first space SP1 when the shaft member 200 rotates. The pressure relief groove 120ds has a curved portion to generate a flow of the sealed fluid from the second space SP2 back to the first space SP1 when the shaft member 200 rotates. Thus, in this embodiment, the fluid sealed in the first space SP1 can be prevented from leaking from the first space SP1 to the second space SP2.

[0055] Furthermore, in this embodiment, as described above, the second seal portion 120 is provided with a pressure relief groove 120ds in addition to the spiral groove 120ss. Therefore, in this embodiment, the path through which pressure (gas) accumulated in the first space SP1 from the second space SP2 is released from the first space SP1 to the second space SP2 through the pumping action generated by the spiral groove 120ss and the like is increased compared to a configuration without the pressure relief groove 120ds. Therefore, in this embodiment, the pressure (gas) accumulated in the first space SP1 can be reduced compared to a configuration without the pressure relief groove 120ds. Furthermore, in this embodiment, since the path length of the pressure relief groove 120ds is shorter than that of the spiral groove 120ss, the pressure (gas) accumulated in the first space SP1 can be efficiently released when the shaft member 200 is stopped, or when the rotational speed of the shaft member 200 is low and the pumping action of the spiral groove 120ss is low.

[0056] Furthermore, for example, when the number of the pressure release 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.

[0057] Thus, in this embodiment, it is possible to suppress leakage of fluid from the sealed space, such as the first space SP1, to the outside while releasing the pressure accumulated in the sealed space. As a result, in this embodiment, it is possible to suppress the pressure in the sealed space from being maintained higher than the normal pressure in the sealed space when the shaft member 200 is stopped, thereby reducing the adverse effects on the sealed space and the components surrounding the sealed space.

[0058] (2. Modification)

[0059] The embodiments described above can be modified in various ways. The following examples illustrate specific modifications that can be applied to the embodiments described above. It is also possible to combine two or more embodiments arbitrarily selected from the following examples within the scope of non-contradiction.

[0060] (Variation 1)

[0061] In the above embodiment, the spiral groove 120ss and the pressure relief groove 120ds are recessed in the -Z direction relative to the base end 120be when the sealing device 100 is not mounted on the housing 300, but the present invention is not limited to this embodiment. Figure 5 As shown, when the sealing device 100 is not attached to the housing 300 , the wall of the spiral groove 120ss and the wall of the pressure relief groove 120ds may protrude in the +Z direction relative to the base end portion 120be.

[0062] Figure 4 : is a schematic cross-sectional view showing a state where the sealing device 100A according to Modification 1 is mounted on the housing 300. Figure 4 The sealing device 100A is schematically shown when it is cut along a plane passing through the central axis AX of the shaft member 200 (using Figure 2 A cross-sectional view of the sealing device 100A when the line A1-A2 shown cuts through the sealing device 100A. Figures 1 to 3 The same elements as those described in are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0063] The sealing device 100A replaces Figure 1 The second sealing portion 120 shown in FIG. 1 has a second sealing portion 120A, and Figure 1 The sealing device 100 shown is the same. Figure 5 The second sealing portion 120A according to Modification 1 will be described.

[0064] Figure 5 : is a cross-sectional view of the second sealing portion 120A according to Modification 1. Figure 5 Indicates the use of Figure 2 The A1-A2 line shown cuts across Figure 2The second sealing portion 120A is a cross-sectional view of the second sealing portion 120A in the portion corresponding to the range AR1 shown.

[0065] When the sealing device 100 is not installed on the housing 300, the surface M1 (surface viewed from the +Z direction) of the sealing lip 120sl of the second sealing portion 120A is located in the +Z direction relative to the surface M2 (surface viewed from the +Z direction) of the base end portion 120be. In addition, a spiral groove 120ss and a pressure relief groove 120ds are provided on the surface M1 (surface viewed from the +Z direction) of the sealing lip 120sl of the second sealing portion 120A. That is, in the second sealing portion 120A, a spiral groove 120ss and a pressure relief groove 120ds are also provided on the sliding surface SLD on which the outer peripheral surface 200op of the shaft component 200 slides. Figure 5 In the shown variant example 1, when the sealing device 100 is not installed on the housing 300, the +Z direction position of the bottom surface of the spiral groove 120ss and the bottom surface of the pressure relief groove 120ds is the same or approximately the same as the +Z direction position of the surface M2 (the surface viewed from the +Z direction) of the base end portion 120be of the second sealing portion 120A.

[0066] The same effects as those of the above-described embodiment can also be obtained in Modification 1. For example, in Modification 1, it is possible to release pressure accumulated in a sealed space while suppressing leakage of fluid in the sealed space such as the first space SP1 to the outside.

[0067] (Variation 2)

[0068] In the above-described embodiment and Modification 1, the depth D1 of the spiral groove 120ss and the depth D2 of the pressure relief groove 120ds are shown as being equal to each other. However, the present invention is not limited to this embodiment. For example, the depth D2 of the pressure relief groove 120ds relative to the sliding surface SLD may be different from the depth D1 of the spiral groove 120ss relative to the sliding surface SLD.

[0069] Figure 6 : is a schematic cross-sectional view showing a state where the sealing device 100B according to Modification 2 is mounted on the housing 300. Figure 6 The sealing device 100B is schematically shown when it is cut along a plane passing through the central axis AX of the shaft member 200 (using Figure 2 A cross-sectional view of the sealing device 100B when the line A1-A2 shown cuts through the sealing device 100B. Figures 1 to 5 The same elements as those described in are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0070] The sealing device 100B replaces Figure 1The second sealing portion 120 shown in FIG. 1 has a second sealing portion 120B. Figure 1 The sealing device 100 shown is the same. Figure 7 The second sealing portion 120B according to Modification 2 will be described.

[0071] Figure 7 : is a cross-sectional view of the second sealing portion 120B according to Modification 2. Figure 7 Indicates the use of Figure 2 The A1-A2 line shown cuts across Figure 2 The cross-sectional view of the second sealing portion 120B is shown when the second sealing portion 120B corresponds to the range AR1. Figures 1 to 5 The same elements as those described in are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0072] In addition to the depth D2 of the pressure relief groove 120ds, Figure 7 The second sealing portion 120B shown is Figures 1 to 3 The second seal portion 120 shown is the same. The second seal portion 120B is formed so that the depth D2 of the pressure relief groove 120ds relative to the sliding surface SLD is shallower than the depth D1 of the spiral groove 120ss relative to the sliding surface SLD.

[0073] In the second modification, the same effects as those of the above embodiment can be obtained. For example, in the second modification, the pressure accumulated in the sealed space can be released while suppressing the leakage of the fluid in the sealed space such as the first space SP1 to the outside. Figure 7 In the second modification shown, the depth D2 of the pressure relief groove 120ds relative to the sliding surface SLD is shallower than the depth D1 of the spiral groove 120ss relative to the sliding surface SLD. Figure 7 In the second modification shown, compared with the case where the depth D2 of the pressure relief groove 120ds relative to the sliding surface SLD is the same as the depth D1 of the spiral groove 120ss relative to the sliding surface SLD, leakage of the fluid sealed in the first space SP1 to the second space SP2 can be suppressed.

[0074] Furthermore, the depth D2 of the pressure relief groove 120ds relative to the sliding surface SLD may be deeper than the depth D1 of the spiral groove 120ss relative to the sliding surface SLD. In Modification 2, by adjusting the depth D1 of the spiral groove 120ss, the depth D2 of the pressure relief groove 120ds, the number of spiral grooves 120ss, and the number of pressure relief grooves 120ds, it is also possible to release pressure (gas) only into the second space SP2 without leaking the sealed fluid, such as oil, from the first space SP1.

[0075] (Variation 3)

[0076] In the above-mentioned embodiment, modification 1 and modification 2, the base end portion 120be of each of the second sealing portion 120, 120A and 120B is embedded in the inner peripheral surface of the cylindrical portion 112cl provided in the support portion 112sp of the first sealing portion 110, but the present invention is not limited to such a method. Figure 8 As shown, the base end portion 120be of each of the second sealing portion 120, 120A and 120B may be embedded in the inner peripheral surface of the cylindrical portion 114cl in the reinforcement ring 114 of the first sealing portion 110.

[0077] Figure 8 : is a schematic cross-sectional view showing a state where the sealing device 100C according to Modification 3 is mounted on the housing 300. Figure 8 The sealing device 100C is schematically shown when it is cut along a plane passing through the central axis AX of the shaft member 200 (using Figure 2 A cross-sectional view of the sealing device 100C when the line A1-A2 shown cuts through the sealing device 100C. Figures 1 to 7 The same elements as those described in are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0078] The sealing device 100C includes a first sealing portion 110C instead of Figure 1 The first sealing portion 110 shown has a second sealing portion 120C instead Figure 1 The second seal 120 is shown.

[0079] In addition to replacing Figure 1 The elastic ring 112 shown has an elastic ring 112C, and the first sealing portion 110C is connected to the elastic ring 112C. Figure 1 The first sealing portion 110 shown is identical. The elastic ring 112C is Figure 1 The main difference of the elastic ring 112 shown is that the elastic ring 112C has a support portion 112Csp instead of the support portion 112sp. Figure 1 The main difference of the support portion 112sp shown is that no support portion 112Csp is provided. Figure 1 The cylindrical portion 112cl is shown.

[0080] The second sealing portion 120C replaces Figure 1 The base end portion 120be shown in FIG. 1 has a base end portion 120Cbe having an inner peripheral surface of the cylindrical portion 114cl embedded in the reinforcement ring 114 of the first sealing portion 110C. Figure 1The second sealing portion 120 shown is the same. That is, in the sealing device 100C, the base end portion 120Cbe of the second sealing portion 120C is embedded in the inner circumferential surface of the cylindrical portion 114cl in the reinforcement ring 114 of the first sealing portion 110C in a manner with a predetermined interference fit. As a result, the base end portion 120Cbe of the second sealing portion 120C is connected to the support portion 112Csp of the first sealing portion 110C and the cylindrical portion 114cl of the reinforcement ring 114, and the second sealing portion 120C is fixed to the first sealing portion 110C. In addition, the fixing method of the second sealing portion 120C is not limited to connection by embedding it into the cylindrical portion 114cl. For example, the base end portion 120Cbe of the second sealing portion 120C can also be bonded to the support portion 112Csp of the first sealing portion 110 and the cylindrical portion 114cl of the reinforcement ring 114.

[0081] The same effects as those of the above embodiment can also be obtained in Modification 3. For example, in Modification 3, it is also 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.

[0082] Explanation of symbols

[0083] 100, 100A, 100B, 100C…sealing device, 110, 110C…first sealing portion, 112, 112C…elastic ring, 112cl…cylindrical portion, 112dl…dustproof lip, 112jo…connecting portion, 112os…outer peripheral sealing portion, 112sp, 112Csp…support portion, 114…reinforcement ring, 114cl…cylindrical portion, 114fg…flange portion, 120, 120 A, 120B, 120C…second sealing portion, 120be, 120Cbe…base end portion, 120ds…pressure relief groove, 120sl…sealing lip portion, 120ss…spiral groove, 200…shaft component, 200op…outer peripheral surface, 300…housing, 300ip…inner peripheral surface, AX…center axis, HLa…shaft hole, HLb…hole, SLD…sliding surface, SP1…first space, SP2…second space.

Claims

1. A sealing device that divides a space between a receiving member having an axial hole and an axial member inserted into the axial hole into a first space and a second space, the sealing device being characterized by: an annular first portion in contact with the inner circumferential surface of the receiving component; and The annular second portion slides on the outer peripheral surface of the shaft member. The second portion includes a first groove extending from the first space to the second space and having a spiral shape on a sliding surface that slides against the outer peripheral surface of the shaft member; and a second groove extending from the first space to the second space and having a curved portion. The path length of the second groove portion is shorter than the path length of the first groove portion.

2. The sealing device according to claim 1, wherein: The second groove portion intersects the first groove portion.

3. The sealing device according to claim 1, wherein: The depth of the second groove portion from the sliding surface is shallower than the depth of the first groove portion from the sliding surface.

4. The sealing device according to claim 2, wherein: The depth of the second groove portion from the sliding surface is shallower than the depth of the first groove portion from the sliding surface.

5. The sealing device according to any one of claims 1 to 4, characterized in that The number of the second grooves is greater than the number of the first grooves.

6. The sealing device according to any one of claims 1 to 4, characterized in that The first space is filled with a fluid to be sealed, and the second space contains a gas. The first groove portion generates a flow that causes the fluid to be sealed to return from the second space to the first space when the shaft member rotates. The second groove portion generates a flow that returns the fluid to be sealed from the second space to the first space when the shaft member rotates.

7. The sealing device according to claim 5, wherein: The first space is filled with a fluid to be sealed, and the second space contains a gas. The first groove portion generates a flow that causes the fluid to be sealed to return from the second space to the first space when the shaft member rotates. The second groove portion generates a flow that returns the fluid to be sealed from the second space to the first space when the shaft member rotates.

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