Sealing device

Abstract

The present invention improves sealing performance pertaining to oozing and leakage, of an object to be sealed, caused by rotary movements in both directions of an attachment target. This sealing device (1) comprises: an inner circumferential surface (10) which is a surface facing the outer circumferential surface of a shaft; and an outer circumferential surface (20) which is a surface facing the inner circumferential surface of a shaft hole. The inner circumferential surface (10) has an inner circumferential recess surface (11) which is an annular surface recessed toward the outer circumferential side. The outer circumferential surface (20) has an outer circumferential recess surface (21) which is an annular surface recessed toward the inner circumferential side. The inner circumferential recess surface (11) of the inner circumferential surface (10) is configured to be in contact with the outer circumferential surface of the shaft. The outer circumferential recess surface (21) of the outer circumferential surface (20) is configured to be in contact with the inner circumferential surface of a shaft hole.

Description

Technical Field

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

Background Art

[0002] Conventionally, a sealing device has been used to seal the space between members that can move relative to each other, such as rotational movement. Some such sealing devices attempt to close the gap between, for example, a shaft and a hole or cylindrical surface through which the shaft is inserted to form two separated spaces. Such sealing devices are required to reduce resistance to rotation (rotational resistance) and improve sealing performance, and various proposals have been made (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described above, some conventional sealing devices have configurations for reducing rotational resistance and improving sealing performance. However, there are cases where improvement in sealing performance regarding leakage of a sealing object such as hydraulic oil due to rotational movement of the sealing device's mounting object, such as a shaft, in both directions is required.

[0005] An object of the present invention is to provide a sealing device capable of improving the sealing performance regarding leakage of a sealing object based on rotational movement of the sealing device's mounting object in both directions.

Means for Solving the Problems

[0006] In order to achieve the above object, a sealing device according to the present invention is an annular sealing device around an axis for sealing an annular space between a shaft and a shaft hole into which the shaft is inserted, and includes an inner peripheral surface which is a surface facing the inner peripheral side surface among the respective surfaces facing each other through the space between the shaft and the shaft hole, and an outer peripheral surface which is a surface facing the outer peripheral side surface among the respective surfaces facing each other through the space between the shaft and the shaft hole. The inner peripheral surface has an inner peripheral concave surface which is an annular surface recessed toward the outer peripheral side around the axis, and the outer peripheral surface has an outer peripheral concave surface which is an annular surface recessed toward the inner peripheral side around the axis. The inner peripheral concave surface of the inner peripheral surface is adapted to contact the inner peripheral side surface among the respective surfaces facing each other through the space between the shaft or the shaft hole, and the outer peripheral concave surface of the outer peripheral surface is adapted to contact the outer peripheral side surface among the respective surfaces facing each other through the space between the shaft or the shaft hole.

[0007] In a sealing device according to an aspect of the present invention, in a cross-section along the axis of the sealing device, a portion located at the position farthest from the axis in a direction orthogonal to the axis of the inner peripheral concave surface is provided at the center or substantially at the center in the axial direction of the inner peripheral concave surface. In a cross-section along the axis of the sealing device, a portion located at the position closest to the axis in a direction orthogonal to the axis of the outer peripheral concave surface is provided at the center or substantially at the center in the axial direction of the outer peripheral concave surface.

[0008] In a sealing device according to an aspect of the present invention, in a cross-section along the axis of the sealing device, a portion located at the position farthest from the axis in a direction orthogonal to the axis of the inner peripheral concave surface is provided on one side in the axial direction of the inner peripheral concave surface. In a cross-section along the axis of the sealing device, a portion located at the position closest to the axis in a direction orthogonal to the axis of the outer peripheral concave surface is provided on one side in the axial direction of the outer peripheral concave surface. One side in the axial direction is the side on the side of the object to be sealed.

[0009] In a sealing device according to an aspect of the present invention, the inner peripheral concave surface forms, at both ends of the inner peripheral surface in the axial direction, a pair of annular surfaces that protrude toward the inner peripheral side around the axis, namely, inner peripheral protruding surfaces; and the outer peripheral concave surface forms, at both ends of the outer peripheral surface in the axial direction, a pair of annular surfaces that protrude toward the outer peripheral side around the axis, namely, outer peripheral protruding surfaces.

[0010] In a sealing device according to an aspect of the present invention, the shaft or the shaft hole rotates in both directions.

Advantages of the Invention

[0011] According to the sealing device of the present invention, it is possible to improve the sealing performance regarding the leakage of the object to be sealed due to the rotational movement in both directions of the object to which the sealing device is attached.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0014] FIG. 1 is a plan view of a sealing device 1 according to a first embodiment of the present invention, FIG. 2 is a perspective view of the sealing device 1, and FIG. 3 is a cross-sectional view taken along the axis x of the sealing device 1. Further, FIG. 4 is an enlarged cross-sectional view showing one of the cross-sections shown in FIG. 3. Hereinafter, for convenience of explanation, the side in the direction of arrow a (see FIG. 3) (one side) is defined as the side of the object to be sealed, and the side in the direction of arrow b (see FIG. 3) is defined as the atmosphere side. The object to be sealed is what the sealing device 1 is to seal, and the side where this object to be sealed exists or is to exist is the side of the object to be sealed. Also, the atmosphere side is the side opposite to the side of the object to be sealed and is the side open to the atmosphere. The atmosphere side does not necessarily have to be open to the atmosphere, and other objects to be sealed may exist. Also, the side in the direction of arrow c (see FIG. 3) is defined as the inner peripheral side, and the side in the direction of arrow d (see FIG. 3) is defined as the outer peripheral side.

[0015] The sealing device 1 according to the present embodiment is a sealing device for sealing an annular space between a shaft that is an object to be attached to the sealing device 1 and a shaft hole that is an object to be attached to the sealing device 1 into which this shaft is inserted. The sealing device 1 is annular around the axis x. The sealing device 1 includes an inner peripheral surface 10 that faces the inner peripheral side surface (outer peripheral surface of the shaft) among the respective surfaces facing each other through the space of the shaft and the shaft hole, and an outer peripheral surface 20 that faces the outer peripheral side surface (inner peripheral surface of the shaft hole) among the respective surfaces facing each other through the space of the shaft and the shaft hole. The inner peripheral surface 10 has an inner peripheral concave surface 11 that is an annular surface around the axis x that is recessed toward the outer peripheral side. The outer peripheral surface 20 has an outer peripheral concave surface 21 that is an annular surface around the axis x that is recessed toward the inner peripheral side. The inner peripheral concave surface 11 of the inner peripheral surface 10 is adapted to contact the outer peripheral surface of the shaft. The outer peripheral concave surface 21 of the outer peripheral surface 20 is adapted to contact the inner peripheral surface of the shaft hole. Hereinafter, the sealing device 1 will be specifically described.

[0016] The objects to which the sealing device 1 is applied include vehicles, construction machines, industrial machines, general-purpose machines, etc. The sealing device 1 is used to seal between a shaft that moves relatively and a shaft hole formed in a housing or the like into which this shaft is inserted in the object to be attached. The sealing device 1 is suitably used for dampers, valves, etc. that perform a two-direction rotational movement in which the shaft or the shaft hole rotates in both rotational directions, one rotational direction such as the positive direction or the negative direction and the other rotational direction opposite thereto. Note that the object to which the sealing device 1 according to the embodiment of the present invention is applied is not limited to the above.

[0017] As shown in FIGS. 1 and 2, the sealing device 1 is an annular or substantially annular member having the axis x as the central axis or substantially central axis. As described above, it has an inner peripheral surface 10 and an outer peripheral surface 20 that face each other. Further, the sealing device 1 has side surfaces 31 and 32 that are surfaces facing each other. The side surface 31 is a surface that extends between the end on the sealing target side of the inner peripheral surface 10 (sealing side end 10a) and the end on the sealing target side of the outer peripheral surface 20 (sealing side end 20a). Also, the side surface 32 is a surface that extends between the end on the atmosphere side of the inner peripheral surface 10 (atmosphere side end 10b) and the end on the atmosphere side of the outer peripheral surface 20 (atmosphere side end 20b). As shown in FIGS. 3 and 4, the shape of the cross section (hereinafter, also simply referred to as the cross section) along the axis x of the sealing device 1 (hereinafter, also simply referred to as the cross-sectional shape) is substantially rectangular.

[0018] As shown in FIGS. 1 and 2, the inner peripheral surface 10 extends in the extending direction of the sealing device 1 and is an annular or substantially annular surface having the axis x as the central axis or substantially central axis. The cross-sectional shape (FIGS. 3 and 4) is uniform or substantially uniform in the extending direction (circumferential direction) of the sealing device 1. Further, the inner peripheral surface 10 has the above-described inner peripheral concave surface 11 and inner peripheral protruding surfaces 12 and 13 formed on both sides of the inner peripheral concave surface 11 by the inner peripheral concave surface 11.

[0019] As shown in FIGS. 3 and 4, in a cross section along the axis x of the sealing device 1, the inner peripheral concave surface 11 is formed such that the bottommost portion 11a of the inner peripheral concave surface 11 is provided at the center or substantially at the center in the axial direction x of the inner peripheral concave surface 11. The bottommost portion 11a is a portion that is located at the position farthest from the axis x in the direction orthogonal to the axis x of the inner peripheral concave surface 11 in the cross section. Specifically, the inner peripheral concave surface 11 is formed such that the contour in the cross section of the inner peripheral concave surface 11 draws an arc-shaped or substantially arc-shaped line, and the bottommost portion 11a of the inner peripheral concave surface 11 is formed to be located at the center or substantially at the center in the axial direction x of the inner peripheral concave surface 11 in the cross section. That is, in the cross section, the inner peripheral concave surface 11 is symmetric or substantially symmetric with respect to the bottommost portion 11a. The inner peripheral concave surface 11 is not limited to a shape having an arc-shaped or substantially arc-shaped contour in the cross section, and may be other shapes such as a shape having a contour drawn by a curve in the cross section, a shape having a contour drawn by a combination of straight lines in the cross section, or a shape having a contour drawn by a combination of a curve and a straight line in the cross section. However, the inner peripheral concave surface 11 preferably has a shape that draws a smooth line in the cross section.

[0020] As shown in FIGS. 3 and 4, due to the inner peripheral concave surface 11, a pair of annular inner peripheral protruding surfaces 12 and 13, which are a pair of surfaces protruding inwardly around the axis x, are formed at both ends of the inner peripheral concave surface 11 of the inner peripheral surface 10. The inner peripheral protruding surface 12 is located on the side of the object to be sealed with respect to the inner peripheral concave surface 11, and the inner peripheral protruding surface 13 is located on the atmosphere side with respect to the inner peripheral concave surface 11. In the cross section, a protruding end portion 12a, which is a portion located closest to the axis x in the direction orthogonal to the axis x of the inner peripheral protruding surface 12, is located on the inner peripheral side in the direction orthogonal to the axis x rather than the inner peripheral concave surface 11. Similarly, in the cross section, a protruding end portion 13a, which is a portion located closest to the axis x in the direction orthogonal to the axis x of the inner peripheral protruding surface 13, is located on the inner peripheral side in the direction orthogonal to the axis x rather than the inner peripheral concave surface 11. Note that, in the cross section, the protruding end portion 12a of the inner peripheral protruding surface 12 may be located at the same position as the connecting portion with the inner peripheral protruding surface 12 of the inner peripheral concave surface 11 in the direction orthogonal to the axis x. Similarly, in the cross section, the protruding end portion 13a of the inner peripheral protruding surface 13 may be located at the same position as the connecting portion with the inner peripheral protruding surface 13 of the inner peripheral concave surface 11 in the direction orthogonal to the axis x. In the cross section, the protruding end portion 12a of the inner peripheral protruding surface 12 and the protruding end portion 13a of the inner peripheral protruding surface 13 may be located at the same position or different positions in the direction orthogonal to the axis x.

[0021] As shown in FIGS. 3 and 4, for example, the inner peripheral protruding surfaces 12 and 13 are provided at both ends of the inner peripheral surface 10 in the axis x direction. The inner peripheral protruding surfaces 12 and 13 do not necessarily have to be provided at both ends of the inner peripheral surface 10 in the axis x direction. In this case, the inner peripheral surface 10 continues further on the side of the object to be sealed than the inner peripheral protruding surface 12, and the inner peripheral surface 10 continues further on the atmosphere side than the inner peripheral protruding surface 13.

[0022] As shown in FIGS. 1 and 2, the outer peripheral surface 20 extends over the extending direction of the sealing device 1, and is an annular or substantially annular surface having the axis x as the central axis or substantially central axis, and the cross-sectional shape (FIGS. 3 and 4) is uniform or substantially uniform over the extending direction (circumferential direction) of the sealing device 1. Further, the outer peripheral surface 20 has the above-described outer peripheral concave surface 21 and outer peripheral protruding surfaces 22 and 23 formed on both sides of the outer peripheral concave surface 21 by the outer peripheral concave surface 21.

[0023] As shown in FIGS. 3 and 4, in the cross-section along the axis x of the sealing device 1, the outer peripheral concave surface 21 is formed such that the bottommost portion 21a of the outer peripheral concave surface 21 is provided at the center or substantially at the center in the axial direction x of the outer peripheral concave surface 21. The bottommost portion 21a is a portion that is located at the position closest to the axis x in the direction orthogonal to the axis x of the outer peripheral concave surface 21 in the cross-section. Specifically, the outer peripheral concave surface 21 is formed such that the contour in the cross-section of the outer peripheral concave surface 21 depicts an arc-shaped or substantially arc-shaped line, and the bottommost portion 21a of the outer peripheral concave surface 21 is formed to be located at the center or substantially at the center in the axial direction x of the outer peripheral concave surface 21 in the cross-section. That is, in the cross-section, the outer peripheral concave surface 21 is symmetric or substantially symmetric with respect to the bottommost portion 21a. The outer peripheral concave surface 21 is not limited to a shape that presents an arc-shaped or substantially arc-shaped contour in the cross-section, and may be other shapes such as a shape that presents a contour drawn by a curve in the cross-section, a shape that presents a contour drawn by a combination of straight lines in the cross-section, or a shape that presents a contour drawn by a combination of a curve and a straight line in the cross-section. However, it is preferable that the outer peripheral concave surface 21 has a shape that depicts a smooth line in the cross-section.

[0024] As shown in FIGS. 3 and 4, on both ends of the outer peripheral concave surface 21 of the outer peripheral surface 20, a pair of annular outer peripheral protruding surfaces 22 and 23 that are a pair of surfaces protruding toward the outer peripheral side around the axis x are formed by the outer peripheral concave surface 21. The outer peripheral protruding surface 22 is located on the sealed object side with respect to the outer peripheral concave surface 21, and the outer peripheral protruding surface 23 is located on the atmosphere side with respect to the outer peripheral concave surface 21. In a cross section, a protruding end portion 22a, which is a portion located at the position farthest from the axis x in the direction orthogonal to the axis x of the outer peripheral protruding surface 22, is located on the outer peripheral side in the direction orthogonal to the axis x rather than the outer peripheral concave surface 21. Similarly, in a cross section, a protruding end portion 23a, which is a portion located at the position farthest from the axis x in the direction orthogonal to the axis x of the outer peripheral protruding surface 23, is located on the outer peripheral side in the direction orthogonal to the axis x rather than the outer peripheral concave surface 21. Note that, in a cross section, the protruding end portion 22a of the outer peripheral protruding surface 22 may be located at the same position as the connection portion with the outer peripheral protruding surface 22 of the outer peripheral concave surface 21 in the direction orthogonal to the axis x. Similarly, in a cross section, the protruding end portion 23a of the outer peripheral protruding surface 23 may be located at the same position as the connection portion with the outer peripheral protruding surface 23 of the outer peripheral concave surface 21 in the direction orthogonal to the axis x. In a cross section, the protruding end portion 22a of the outer peripheral protruding surface 22 and the protruding end portion 23a of the outer peripheral protruding surface 23 may be located at the same position or different positions in the direction orthogonal to the axis x.

[0025] The outer peripheral protruding surfaces 22 and 23 are provided at both ends of the outer peripheral surface 20 in the axis x direction, for example, as shown in FIGS. 3 and 4. The outer peripheral protruding surfaces 22 and 23 may not be provided at both ends of the outer peripheral surface 20 in the axis x direction. In this case, the outer peripheral surface 20 continues further on the sealed object side than the outer peripheral protruding surface 22, and the outer peripheral surface 20 continues further on the atmosphere side than the outer peripheral protruding surface 23.

[0026] The sealing device 1 is formed such that the inner peripheral concave surface 11 contacts the outer peripheral surface (bottom surface of the groove) of the shaft as described later in the usage state where the sealing device 1 is attached to the object to be attached. Further, the sealing device 1 is formed such that the outer peripheral concave surface 21 contacts the inner peripheral surface of the shaft hole as described later in the usage state of the sealing device 1. That is, in the usage state of the sealing device 1 described later, within the range of the inner peripheral concave surface 11 and the outer peripheral concave surface 21, the sealing device 1 is sandwiched between the outer peripheral surface of the shaft and the inner peripheral surface of the shaft hole, and the compression rate in the direction orthogonal to the axis x or in a direction substantially orthogonal to the axis x is 0% or more.

[0027] As shown in FIGS. 1 and 2, the side surfaces 31 and 32 extend over the extending direction of the sealing device 1 and are annular or substantially annular surfaces having the axis x as the central axis or substantially the central axis, and the cross-sectional shape (FIGS. 3 and 4) is uniform or substantially uniform over the extending direction (circumferential direction) of the sealing device 1. Further, as shown in FIGS. 3 and 4, the side surfaces 31 and 32 extend along a plane orthogonal to the axis x, and for example, extend parallel or substantially parallel to a plane orthogonal to the axis x.

[0028] The inner peripheral protruding surfaces 12 and 13 are symmetric or substantially symmetric with respect to a straight line orthogonal to the axis x in a cross section, and the outer peripheral protruding surfaces 22 and 23 are symmetric or substantially symmetric with respect to a straight line orthogonal to the axis x in a cross section. Also, the inner peripheral protruding surface 12 and the outer peripheral protruding surface 22 are symmetric or substantially symmetric with respect to a straight line parallel to the axis x in a cross section. Further, the inner peripheral protruding surface 13 and the outer peripheral protruding surface 23 are symmetric or substantially symmetric with respect to a straight line parallel to the axis x in a cross section. Also, the inner peripheral concave surface 11 and the outer peripheral concave surface 21 are symmetric or substantially symmetric with respect to a straight line parallel to the axis x in a cross section. The inner peripheral protruding surfaces 12 and 13 do not have to be symmetric with respect to a straight line orthogonal to the axis x in a cross section. Also, the outer peripheral protruding surfaces 22 and 23 do not have to be symmetric with respect to a straight line orthogonal to the axis x in a cross section. Also, the inner peripheral protruding surface 12 and the outer peripheral protruding surface 22 do not have to be symmetric with respect to a straight line parallel to the axis x in a cross section. Further, the inner peripheral protruding surface 13 and the outer peripheral protruding surface 23 do not have to be symmetric with respect to a straight line parallel to the axis x in a cross section. Also, the inner peripheral concave surface 11 and the outer peripheral concave surface 21 do not have to be symmetric with respect to a straight line parallel to the axis x in a cross section.

[0029] The sealing device 1 is a rubber-like elastic body, and examples of the rubber material of the sealing device 1 include fluororubber (FKM), ethylene propylene rubber (EPDM), hydrogenated nitrile rubber (H-NBR), nitrile rubber (NBR), acrylic rubber (ACM), ethylene acrylic rubber (AEM), vinyl methyl silicone rubber (VMQ), fluorosilicone rubber (FVMQ), etc. The sealing device 1 is integrally made of a rubber-like elastic body.

[0030] Next, the operation of the sealing device 1 having the above-described configuration will be described.

[0031] As described above, the sealing device 1 is used to seal the annular space between the shaft and the shaft hole into which the shaft is inserted. The sealing device 1 is used to seal the annular space between, for example, the shaft 50 and the shaft hole 61 into which the shaft 50 is inserted, as shown in FIG. 5. The shaft hole 61 is a through hole formed in the housing 60, and the housing 60 is, for example, a cylindrical or tubular member. An annular groove 51 is formed around the axis of the shaft 50, and the sealing device 1 is accommodated in this groove 51 to be in a use state. Note that FIG. 5 is a cross-sectional view showing the sealing device 1 in a use state attached to the shaft 50 and the shaft hole 61 of the housing 60, which are the objects to which the sealing device 1 is attached.

[0032] The groove 51 is recessed from the outer peripheral surface 50a of the shaft 50 and opens into the space between the shaft 50 and the shaft hole 61, as shown in FIG. 5. Further, as shown in FIG. 5, the groove 51 has a pair of side surfaces 51a, 51b facing each other, and also has a bottom surface 51c extending between the side surfaces 51a, 51b. The side surface 51a is the side surface located on the sealing object side (the arrow a direction side), and the side surface 51b is the side surface located on the atmosphere side (the arrow b direction side). The groove 51 may be formed on the inner peripheral surface 61a of the shaft hole 61 of the housing 60 instead of the shaft 50. Also, grooves may be formed on the shaft 50 and the housing 60. The object to be attached is, for example, a valve such as a damper or an EGR valve, and the shaft 50 and the housing 60 rotate relative to each other in both directions. In the object to be attached, the shaft 50 may rotate in both directions while the housing 60 is fixed, the shaft 50 may be fixed while the housing 60 rotates in both directions, or the shaft 50 and the housing 60 may rotate in both directions relative to each other.

[0033] As shown in Fig. 5, in the installed state, the sealing device 1 attached to the shaft 50 and the housing 60 to be attached is compressed between the bottom surface 51c of the groove 51 and the inner peripheral surface 61a of the shaft hole 61 of the housing 60, thereby closing the gap between the shaft 50 and the shaft hole 61 of the housing 60. Thereby, the space between the shaft 50 and the shaft hole 61 is sealed, and the space on the sealed object side is sealed. For example, when another sealed object is also enclosed in the space on the atmosphere side, the space on the atmosphere side may also be sealed, and the sealing device 1 may seal the space on the atmosphere side.

[0034] As shown in Fig. 5, in the installed state, the sealing device 1 is compressed between the bottom surface 51c of the groove 51 and the inner peripheral surface 61a of the shaft hole 61 of the housing 60. At this time, the sealing device 1 is also deformed in the axial direction of the axis x and extends in the axial direction of the axis x. As described above, the entire inner peripheral concave surface 11 of the sealing device 1 is in contact with the bottom surface 51c of the groove 51, and the entire outer peripheral concave surface 21 of the sealing device 1 is in contact with the inner peripheral surface 61a of the shaft hole 61. At this time, in the range of the inner peripheral concave surface 11 and the outer peripheral concave surface 21, the compression rate of the sealing device 1 in the direction perpendicular to the axis x or in the direction substantially perpendicular to the axis x is 0% or more.

[0035] In addition, the inner peripheral protruding surfaces 12 and 13 of the inner peripheral surface 10 of the sealing device 1 are pressed against the bottom surface 51c of the groove 51 of the shaft 50, and the outer peripheral protruding surfaces 22 and 23 of the outer peripheral surface 20 of the sealing device 1 are pressed against the inner peripheral surface 61a of the shaft hole 61.

[0036] In this way, in the installed state, in addition to the inner peripheral protruding surfaces 12 and 13 of the inner peripheral surface 10, the entire inner peripheral concave surface 11 of the sealing device 1 is in contact with the bottom surface 51c of the groove 51. Therefore, the width in the axial direction of the region in contact with the bottom surface 51c of the groove 51 of the sealing device 1 in the installed state is larger than the width in the axial direction between the inner peripheral protruding surfaces 12 and 13 of the sealing device 1 in the free state without load shown in Figs. 1 to 4. Therefore, the sealing device 1 can increase the contact area (sealing surface) with respect to the bottom surface 51c of the groove 51 of the sealing device 1 in the installed state.

[0037] Similarly, in the operating state, in addition to the outer peripheral projecting surfaces 22, 23 of the outer peripheral surface 20, the entire outer peripheral concave surface 21 of the sealing device 1 is in contact with the inner peripheral surface 61a of the shaft hole 61. For this reason, the width in the axial direction of the region of the sealing device 1 in contact with the inner peripheral surface 61a of the shaft hole 61 in the operating state is larger than the width in the axial direction between the outer peripheral projecting surfaces 22, 23 of the sealing device 1 in the unloaded free state shown in FIGS. 1 to 4. Therefore, the sealing device 1 can increase the contact area with respect to the inner peripheral surface 61a of the shaft hole 61 of the sealing device 1 in the operating state.

[0038] In this way, the sealing device 1 can increase the contact area with respect to the bottom surface 51c of the groove 51 of the sealing device 1 in the operating state, can increase the contact area with respect to the inner peripheral surface 61a of the shaft hole 61 of the sealing device 1 in the operating state, and can improve the sealing performance of the sealing device 1.

[0039] When the rotation direction of the shaft 50 or the housing 60 is switched (the rotation is reversed) or when the shaft 50 is stationary, etc., the sealing object may enter the contact surface on the inner peripheral surface 10 side or the contact surface on the outer peripheral surface 20 side of the sealing device 1. Even in this case, since the contact area of the sealing device 1 in the operating state is large as described above, it is difficult for the sealing object that has entered the contact surface of the sealing device 1 to reach the atmosphere side on the opposite side. In this way, the sealing device 1 can suppress the leakage of the sealing object due to the two-way rotational movement of the object to be attached.

[0040] Further, the inner peripheral projecting surfaces 12, 13 of the inner peripheral surface 10 are high compression parts, and the surface pressure of the contact surface of the sealing device 1 protrudes at the inner peripheral projecting surfaces 12, 13. Similarly, the outer peripheral projecting surfaces 22, 23 of the outer peripheral surface 20 are high compression parts, and the surface pressure of the contact surface of the sealing device 1 protrudes at the outer peripheral projecting surfaces 22, 23. For this reason, in the operating state, peak surface pressure can be generated on the sealing object side and the atmosphere side of the contact surface of the sealing device 1, the surface pressure gradient can be increased, and it can be made difficult for the sealing object to enter the inside of the contact surface. Thereby, the sealing performance of the sealing device 1 can be improved.

[0041] Further, as described above, the inner circumferential concave surface 11 of the sealing device 1 has a compression rate of 0% or more in the use state, and the outer circumferential concave surface 21 of the sealing device 1 has a compression rate of 0% or more in the use state. Therefore, as described above, while increasing the contact surface, the rotational reaction force generated on the contact surface can be reduced, the driving torque of the shaft 50 or the housing 60 can be reduced, and the wear of the sealing device 1, the bottom surface 51c of the groove 51, or the inner circumferential surface 61a of the shaft hole 61 can be reduced.

[0042] Also, as described above, the sealing device 1 has the inner circumferential concave surface 11 and the outer circumferential concave surface 21 on the contact surface. The contact surface pressure in the use state decreases from the sealing object side toward the atmosphere side, and the surface pressure increases from the bottommost part 11a of the inner circumferential concave surface 11 and the bottommost part 21a of the outer circumferential concave surface 21. Therefore, for example, when switching the rotation direction of the shaft 50 or the housing 60, or when the movement of the object to be attached stops, the sealing object that has entered from the sealing object side toward the atmosphere side can be returned to the sealing object side. Thereby, the leakage of the sealing object can be suppressed. Similarly, when another sealing object is sealed in the space on the atmosphere side, the leakage of this other sealing object can be suppressed.

[0043] In the inner circumferential concave surface 11, the bottommost part 11a is located at the center or substantially at the center in the axial direction x. In the outer circumferential concave surface 21, the bottommost part 21a is located at the center or substantially at the center in the axial direction x. Therefore, the sealing device 1 can similarly exhibit the action of returning the above-described sealing object on the sealing object side and the atmosphere side of the inner circumferential concave surface 11 and the outer circumferential concave surface 21. Therefore, the sealing device 1 can be suitably used for an object to be attached in which another sealing object is sealed not only in the space on the sealing object side but also in the space on the atmosphere side.

[0044] Thus, according to the sealing device 1 according to the first embodiment of the present invention, the sealing performance regarding the leakage of the sealing object based on the bidirectional rotational movement of the shaft 50 or the housing 60 of the sealing device 1 can be improved.

[0045] Next, the sealing device 2 according to the second embodiment of the present invention will be described.

[0046] FIG. 6 is a cross-sectional view taken along the axis x of the sealing device 2 according to the second embodiment of the present invention, and FIG. 7 is an enlarged cross-sectional view showing one of the cross-sections of the sealing device 2. The sealing device 2 according to the second embodiment of the present invention differs from the sealing device 1 according to the first embodiment of the present invention in the form of the inner peripheral concave surface and the outer peripheral concave surface, and has an inner peripheral concave surface 15 and an outer peripheral concave surface 25 that are different from the inner peripheral concave surface 11 and the outer peripheral concave surface 21 of the above-described sealing device 1. Hereinafter, regarding the configuration of the sealing device 2, the same components as those of the above-described sealing device 1 or components having the same or similar functions will be denoted by the same reference numerals and their description will be omitted, and different configurations will be described.

[0047] As shown in FIGS. 6 and 7, the inner peripheral concave surface 15 of the inner peripheral surface 10 of the sealing device 2 is recessed toward the outer peripheral side, similarly to the inner peripheral concave surface 11 of the inner peripheral surface 10 of the sealing device 1, and has a bottommost portion 15a corresponding to the bottommost portion 11a of the inner peripheral concave surface 11. The bottommost portion 15a is a portion located at the position farthest from the axis x in the direction orthogonal to the axis x of the inner peripheral concave surface 15 in the cross-section. The cross-sectional shape of the inner peripheral concave surface 15 is different from the cross-sectional shape of the inner peripheral concave surface 11, and the bottommost portion 15a is not located at the center or substantially at the center in the axis x direction. The cross-sectional shape of the inner peripheral concave surface 15 is not symmetric or substantially symmetric with respect to the bottommost portion 15a. In the cross-section, the bottommost portion 15a is provided on the sealing object side in the axis x direction of the inner peripheral concave surface 15. That is, in the cross-section, the bottommost portion 15a is provided on the sealing object side rather than at the center in the axis x direction of the inner peripheral concave surface 15.

[0048] The inner peripheral concave surface 15 has a shape such as a shape presenting a contour drawn by a curve in the cross-section, a shape presenting a contour drawn by a combination of straight lines in the cross-section, a shape presenting a contour drawn by a combination of a curve and a straight line in the cross-section, etc. However, the inner peripheral concave surface 15 preferably has a shape that draws a smooth line in the cross-section. As described above, in the cross-section, the bottommost portion 15a of the inner peripheral concave surface 15 is provided on the sealing object side, and the width in the axis x direction is larger on the atmosphere side portion than on the sealing object side portion of the inner peripheral concave surface 15 with respect to the bottommost portion 15a of the inner peripheral concave surface 15.

[0049] Also, as shown in FIGS. 6 and 7, the outer peripheral concave surface 25 of the outer peripheral surface 20 of the sealing device 2 is recessed inwardly in the same manner as the outer peripheral concave surface 21 of the outer peripheral surface 20 of the sealing device 1, and has a bottommost portion 25a corresponding to the bottommost portion 21a of the outer peripheral concave surface 21. The bottommost portion 25a is the portion that is located at the position closest to the axis x in the direction orthogonal to the axis x of the outer peripheral concave surface 25 in the cross section. Unlike the cross-sectional shape of the outer peripheral concave surface 21, the bottommost portion 25a of the outer peripheral concave surface 25 is not located at the center or substantially at the center in the axis x direction. The cross-sectional shape of the outer peripheral concave surface 25 is not symmetric or substantially symmetric with respect to the bottommost portion 25a. In the cross section, the bottommost portion 25a is provided on the sealing object side in the axis x direction of the outer peripheral concave surface 25. That is, in the cross section, the bottommost portion 25a is provided on the sealing object side rather than at the center in the axis x direction of the outer peripheral concave surface 25.

[0050] The outer peripheral concave surface 25 has a shape such as a shape presenting a contour drawn by a curve in the cross section, a shape presenting a contour drawn by a combination of straight lines in the cross section, a shape presenting a contour drawn by a combination of a curve and a straight line in the cross section, etc. However, the outer peripheral concave surface 25 preferably has a shape that draws a smooth line in the cross section. As described above, in the cross section, the bottommost portion 25a of the outer peripheral concave surface 25 is provided on the sealing object side, and the width in the axis x direction is larger in the portion on the atmosphere side than in the portion on the sealing object side with respect to the bottommost portion 25a of the outer peripheral concave surface 25.

[0051] Similar to the sealing device 1, the inner peripheral concave surface 15 of the sealing device 2 is formed so as to contact the bottom surface 51c of the groove 51 of the shaft 50 in the usage state where the sealing device 2 is attached to the object to be attached. Also, similar to the sealing device 1, the outer peripheral concave surface 25 of the sealing device 2 is formed so as to contact the inner peripheral surface 61a of the shaft hole 61 in the usage state of the sealing device 2. That is, in the usage state of the sealing device 2 described later, within the range of the inner peripheral concave surface 15 and the outer peripheral concave surface 25, the sealing device 2 is sandwiched between the bottom surface 51c of the groove 51 of the shaft 50 and the inner peripheral surface 61a of the shaft hole 61, and the compression rate in the direction orthogonal to the axis x or in a direction substantially orthogonal to the axis x is 0% or more.

[0052] In the cross-section of the sealing device 2, the inner peripheral concave surface 15 and the outer peripheral concave surface 25 are symmetric or substantially symmetric with respect to a straight line parallel to the axis x. In the cross-section of the sealing device 2, the inner peripheral concave surface 15 and the outer peripheral concave surface 25 do not have to be symmetric with respect to a straight line parallel to the axis x.

[0053] Next, the operation of the sealing device 2 having the above-described configuration will be described.

[0054] The sealing device 2 is used, similar to the above-described sealing device 1, to seal the annular space between the shaft and the shaft hole into which this shaft is inserted. In the usage state, the sealing device 2 is housed in the groove 51 of the shaft 50, for example, as shown in FIG. 8, to seal the annular space between the shaft 50 and the shaft hole 61 into which the shaft 50 is inserted. Note that FIG. 8 is a cross-sectional view showing the sealing device 2 in the usage state where the sealing device 2 is attached to the shaft 50 which is the object to be attached and the shaft hole 61 of the housing 60.

[0055] In the usage state, the sealing device 2 operates in the same manner as the above-described sealing device 1 and exhibits the same effects.

[0056] Also, as described above, in the cross-section, the bottommost part 15a is provided on the sealing object side rather than at the center in the axial direction x of the inner peripheral concave surface 15, and the width in the axial direction x of the part on the atmosphere side rather than the bottommost part 15a of the inner peripheral concave surface 15 is larger than the width in the axial direction x of the part on the sealing object side rather than the bottommost part 15a of the inner peripheral concave surface 15. For this reason, even when the sealing object enters from the sealing object side into the contact surface part during the rotation direction switching or at rest of the shaft 50 or the housing 60, since the width in the axial direction x of the part on the atmosphere side rather than the bottommost part 15a of the inner peripheral concave surface 15 is large, the action of returning the entered sealing object to the sealing object side works within a large range, and the action of returning the sealing object to the sealing object side can be improved.

[0057] Also, as described above, in the cross-section, the bottommost part 25a is provided on the sealing object side rather than at the center in the axial direction x of the outer peripheral concave surface 25, and the width in the axial direction x of the part on the atmosphere side rather than the bottommost part 25a of the outer peripheral concave surface 25 is larger than the width in the axial direction x of the part on the sealing object side rather than the bottommost part 25a of the outer peripheral concave surface 25. For this reason, even when the sealing object enters from the sealing object side into the contact surface part during the rotation direction switching or at rest of the shaft 50 or the housing 60, since the width in the axial direction x of the part on the atmosphere side rather than the bottommost part 25a of the outer peripheral concave surface 25 is large, the action of returning the entered sealing object to the sealing object side works within a large range, and the action of returning the sealing object to the sealing object side can be improved.

[0058] Thus, according to the sealing device 2, the action of returning the sealing object to the sealing object side in the inner peripheral concave surface 15 and the outer peripheral concave surface 25 can be improved, and the sealing performance can be further improved. For this reason, the sealing device 2 can be suitably used for an attachment object in which no other sealing object is sealed on the atmosphere side.

[0059] Thus, according to the sealing device 2 according to the second embodiment of the present invention, the sealing performance regarding the seepage and leakage of the sealing object based on the bidirectional rotational movement of the shaft 50 or the housing 60 of the sealing device 2 can be improved.

[0060] The embodiments of the present invention have been described above. However, the present invention is not limited to the sealing devices 1 and 2 according to the above embodiments of the present invention, and includes all aspects included in the concept and scope of claims of the present invention. Also, each component may be selectively combined as appropriate so as to achieve at least a part of the above-described problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above embodiment may be appropriately changed according to the specific usage mode of the present invention.

Description of Reference Numerals

[0061] 1, 2... Sealing device, 10... Inner peripheral surface, 10a... Sealing side end, 10b... Atmosphere side end, 11, 15... Inner peripheral concave surface, 11a, 15a... Lowest bottom, 12, 13... Inner peripheral protruding surface, 12a, 13a... Protruding end portion, 20... Outer peripheral surface, 20a... Sealing side end, 20b... Atmosphere side end, 21, 25... Outer peripheral concave surface, 21a, 25a... Lowest bottom, 22, 23... Outer peripheral protruding surface, 22a, 23a... Protruding end portion, 31, 32... Side surface, 50... Shaft, 50a... Outer peripheral surface, 51... Groove, 51a, 51b... Side surface, 51c... Bottom surface, 60... Housing, 61... Shaft hole, 61a... Inner peripheral surface, x... Axis

Claims

1. An annular sealing device around an axis for achieving sealing of an annular space between a shaft and a shaft hole into which the shaft is inserted, an inner peripheral surface which is a surface facing an inner peripheral side surface among the respective surfaces facing each other through the space between the shaft and the shaft hole, and an outer peripheral surface which is a surface facing an outer peripheral side surface among the respective surfaces facing each other through the space between the shaft and the shaft hole, the inner peripheral surface has an inner peripheral concave surface which is an annular surface recessed toward the outer peripheral side around the axis, the outer peripheral surface has an outer peripheral concave surface which is an annular surface recessed toward the inner peripheral side around the axis, the inner peripheral concave surface of the inner peripheral surface is adapted to contact the inner peripheral side surface among the respective surfaces facing each other through the space between the shaft and the shaft hole, the outer peripheral concave surface of the outer peripheral surface is adapted to contact the outer peripheral side surface among the respective surfaces facing each other through the space between the shaft and the shaft hole, In a cross section of the sealing device along the axis, a portion located at the position farthest from the axis in a direction orthogonal to the axis of the inner peripheral concave surface is provided on one side in the axial direction of the inner peripheral concave surface, In a cross section of the sealing device along the axis, a portion located at the position closest to the axis in a direction orthogonal to the axis of the outer peripheral concave surface is provided on one side in the axial direction of the outer peripheral concave surface, One side in the axial direction is the side of the object to be sealed, characterized in that it is a sealing device.

2. By the inner peripheral concave surface, a pair of inner peripheral protruding surfaces which are annular surfaces protruding toward the inner peripheral side around the axis are formed at both ends of the inner peripheral surface in the axial direction, By the outer peripheral concave surface, a pair of outer peripheral protruding surfaces which are annular surfaces protruding toward the outer peripheral side around the axis are formed at both ends of the outer peripheral surface in the axial direction, characterized in that it is the sealing device according to Claim 1.

3. The sealing device according to claim 1, wherein the shaft or the shaft hole is characterized by performing rotational movement in both directions.

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