sealing device

Abstract

This suppresses wear on the sealing material while preventing a decrease in sealing performance. [Solution] The sealing device 1 comprises a sealing member 10, a backup ring 20, and a holding member 30. The sealing member 10 is an annular member. The backup ring 20 is an annular member. The holding member 30 is an annular member that holds the sealing member 10 and the backup ring 30. The sealing member 10 is configured to contact the shaft 120 at its inner circumference end 10a. The backup ring 20 is configured to contact the sealing member 10 when a force that releases this contact is applied to the sealing member 10 that is in contact with the shaft 120.

Description

Technical Field

[0001] The present invention relates to a sealing device, and particularly to a sealing device having a resin seal member.

Background Art

[0002] Conventionally, for sealing around a rotating shaft in a fluid mechanism such as an air compressor, a sealing device having a resin seal member with better wear resistance than a rubber seal member has been used. In such a sealing device, in order to improve the durability of the resin seal member, there is a device provided with a leaf spring for pressing the seal member. (For example, refer to Patent Document 1.).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the above-described sealing device is used in a mechanism where a high-pressure fluid acts, such as an air compressor, the high-pressure fluid may act and the seal member may move away from the rotating shaft, resulting in a decrease in sealing performance. On the other hand, when trying to prevent the seal member from moving away from the rotating shaft by increasing the pressing force of the leaf spring, the wear of the seal member is promoted. Therefore, for a conventional sealing device, a configuration that can prevent wear of the seal member while preventing a decrease in sealing performance is required.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a sealing device capable of suppressing wear of the seal member while suppressing a decrease in sealing performance.

Means for Solving the Problems

[0006] To achieve the above objective, the sealing device according to the present invention is a sealing device for sealing an annular gap between a through hole and a shaft passing through the through hole, comprising: a sealing member which is an annular member around the axis; a backup ring which is an annular member around the axis; and a holding member which is an annular member around the axis that holds the sealing member and the backup ring, wherein the sealing member is in contact with the shaft at its inner circumference end, and the backup ring is in contact with the sealing member when a force that releases the contact is applied to the sealing member that is in contact with the shaft.

[0007] In a sealing device according to one aspect of the present invention, the backup ring is configured to contact the sealing member when the sealing member is deformed by the force.

[0008] In a sealing device according to one aspect of the present invention, the backup ring is positioned to contact the sealing member so that the sealing member does not deform due to the force.

[0009] In a sealing device according to one aspect of the present invention, the backup ring is in contact with the sealing member on which the force is not acting, such that a reaction force of a predetermined magnitude is generated with respect to the backup ring.

[0010] In a sealing device according to one aspect of the present invention, the backup ring is configured such that the sealing member on which the force is not applied does not generate a reaction force with respect to the backup ring.

[0011] In a sealing device according to one aspect of the present invention, the backup ring is configured to contact the tip end of the inner circumference end of the sealing member.

[0012] In a sealing device according to one aspect of the present invention, the backup ring is configured to contact the portion of the inner circumference end of the sealing member that is on the outer circumference side rather than the tip end.

[0013] In a sealing device according to one aspect of the present invention, the backup ring is provided on one side in the axial direction relative to the sealing member.

[0014] In a sealing device according to one aspect of the present invention, the backup ring has a root portion which is an annular part and a support portion which is an annular part extending from the root portion toward the axis, wherein the support portion is tapered toward one side in the axial direction.

[0015] In a sealing device according to one aspect of the present invention, the tip end of the support portion of the backup ring is radially opposed from the outer circumference to the tip end of the inner circumference end of the sealing member, which is deformed to one side in the axial direction and whose inner circumference end is in contact with the shaft.

[0016] In a sealing device according to one aspect of the present invention, the tip end of the support portion of the backup ring is deformed to one side in the axial direction and faces, radially from the outer side, the portion of the inner circumference end of the sealing member that is in contact with the shaft, which is on the outer circumference side than the tip end.

[0017] In a sealing device according to one aspect of the present invention, the backup ring is harder than the sealing member.

[0018] In a sealing device according to one aspect of the present invention, the backup ring is elastic. [Effects of the Invention]

[0019] The sealing device according to the present invention can suppress wear of the sealing member while suppressing a decrease in sealing performance. [Brief explanation of the drawing]

[0020] [Figure 1] This is a cross-sectional view showing a plane containing an axis, illustrating the schematic configuration of a sealing device according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view showing one side with respect to the axis of the sealing device shown in FIG. 1. [Figure 3] It is a partial cross-sectional view showing the sealing device in a use state attached between the through-hole of the housing of the air compressor and the shaft. [Figure 4] It is a partial cross-sectional perspective view showing a part of the backup ring cut along a plane along the axis. [Figure 5] It is a partial cross-sectional view showing an example of a state in which the tip of the backup ring is in contact with the inner peripheral end of the seal member under the action of a high-pressure object to be sealed. [Figure 6] It is a partial cross-sectional view showing another example of a state in which the tip of the backup ring is in contact with the inner peripheral end of the seal member under the action of a high-pressure object to be sealed. [Figure 7] It is a partial cross-sectional view showing still another example of a state in which the tip of the backup ring is in contact with the inner peripheral end of the seal member under the action of a high-pressure object to be sealed. [Figure 8] It is a partially enlarged cross-sectional view showing the use state of the sealing device according to the first modification. [Figure 9] It is a partially enlarged cross-sectional view showing the use state of the sealing device according to the second modification. [Figure 10] It is a partially enlarged cross-sectional view showing the use state of the sealing device according to the third modification. [Figure 11] It is a partially enlarged cross-sectional view showing another modification of the sealing device. [Figure 12] It is a partially enlarged cross-sectional view showing still another modification of the sealing device.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, not all of the plurality of components are labeled, and the labels of some of the plurality of components may be omitted. <00​​The sealing device according to the present invention is a sealing device that seals an annular gap between a through hole and a shaft passing through the through hole. The sealing device according to the present invention is applied to fluid mechanisms and fluid machines such as air compressors, for example. Specifically, for example, in fluid mechanisms and fluid machines, it is used between a through hole formed in a housing and a rotating shaft passing through the through hole. The sealing device according to the present invention is installed between a through hole formed in a housing and a shaft passing through the through hole to seal the gap between the shaft and the through hole. However, the application of the sealing device according to the present invention is not limited to this. The sealing device according to the present invention can be applied to various devices and mechanisms. Below, as an example, the sealing device according to an embodiment of the present invention will be described with an air compressor as the target application.

[0023] Figure 1 is a cross-sectional view showing a schematic configuration of a sealing device 1 according to an embodiment of the present invention, with respect to a plane including axis x. Figure 2 is a cross-sectional view showing one side of the sealing device 1 shown in Figure 1 with respect to axis x. Figure 3 is a partial cross-sectional view showing the sealing device 1 in use, installed between the through hole 111 of the housing 110 of the air compressor 100 and the shaft 120.

[0024] As shown in Figures 1-3, the sealing device 1 comprises a sealing member 10, a backup ring 20, and a holding member 30. The sealing member 10 is an annular member around axis x. The backup ring 20 is an annular member around axis x. The holding member 30 is an annular member around axis x that holds the sealing member 10 and the backup ring 30. The sealing member 10 is configured to contact the shaft 120 at its inner circumference end 10a, which is the inner circumference end. The backup ring 20 is configured to contact the sealing member 10 when a force that releases this contact with the shaft 120 is applied to the sealing member 10. The configuration of the sealing device 1 will be described in detail below. Note that in the operating state shown in Figure 3, no force that releases contact with the shaft 120 is applied to the sealing member 10.

[0025] In the x-axis direction, one side (the side in the direction of arrow a in Figure 1) is, for example, the atmospheric side, which is open to the atmosphere, and the other side (the side in the direction of arrow b in Figure 1) is the side opposite to the atmospheric side, which is the side where the object to be sealed by the sealing device 1 is located. Furthermore, the radial direction is perpendicular to the x-axis direction, and the side in the radial direction away from the x-axis (the side in the direction of arrow c in Figure 1) is the outer circumference side, and the side in the radial direction approaching the x-axis (the side in the direction of arrow d in Figure 1) is the inner circumference side.

[0026] As described above, the sealing member 10 is an annular member around axis x. The sealing member 10 is an annular plate-shaped member around axis x, as shown in Figures 1 and 2, and has a pair of annular surfaces, a contact side 11 and a back side 12, which are opposite each other in the direction of axis x. The sealing member 10 has an annular inner end 13 at the inner circumference side and an annular outer end 14 at the outer circumference side. The inner end 13 defines a space (through hole) that penetrates the sealing member 10 in the direction of axis x on the inner circumference side. The inner end 13 extends, for example, along a circle centered on axis x. Similarly, the outer end 14 extends, for example, along a circle centered on axis x.

[0027] The sealing member 10 is elastically deformable or capable of elastic deformation, and in its undeformed state, as shown in Figures 1 and 2, it extends along a plane perpendicular to the axis x. The contact side 11 faces the object to be sealed, and the back surface 12 faces the atmosphere. As shown in Figure 3, the sealing member 10 is inserted into the inner circumference end 13 toward the object to be sealed, deforms toward the atmosphere, and the inner circumference end 10a comes into contact with the shaft 120 at the contact side 11. Specifically, the tip 15 of the sealing member 10 comes into contact with the shaft 120. The tip 15 is a part of the tip side of the inner circumference end 13a, including the inner circumference end 13 and its vicinity. In other words, the diameter D1 of the inner circumference end 13 is larger than the diameter of the outer circumference surface 121 of the shaft 120. The contact side 11 is, for example, a surface extending on a plane or substantially plane. Similarly, the back surface 12 is, for example, a surface extending on a plane or substantially plane. Furthermore, the contact surface 11 is not limited to a surface extending on a flat plane. The contact surface 11 may, for example, be a surface extending on a curved surface. Similarly, the back surface 12 is not limited to a surface extending on a flat plane. The back surface 12 may, for example, be a surface extending on a curved surface.

[0028] The sealing member 10 has the configuration described above, and when the shaft 120 enters the space defined by the inner circumferential end 13, the inner circumferential end 10a deforms, generating a predetermined clamping force F1 toward the outer circumferential surface 121 of the shaft 120 (radially). In other words, the diameter (diameter D1) of the inner circumferential end 13 is set, the overlap of the sealing member 10 relative to the shaft 120 is set, and the thickness T1 of the sealing member 10 is also set so that this predetermined clamping force F1 is generated. The thickness T1 of the sealing member 10 is the distance between the contact surface 11 and the back surface 12 in the axial x direction. In particular, the thickness T1 of the sealing member 10 is the thickness at the inner circumferential end 10a.

[0029] As described above, the sealing member 10 is elastically deformable or capable of elastic deformation, and possesses flexibility and stretchability. The sealing member 10 is made of resin, for example. Examples of resin materials for the sealing member 10 include PTFE (polytetrafluoroethylene), POM (polyacetal), PPS (polyphenylene sulfide), PA (polyamide), PEEK (polyetheretherketone), etc. However, the resin material for the sealing member 10 is not limited to these. Furthermore, the sealing member 10 is not limited to resin and may be formed from other materials such as rubber.

[0030] As described above, the backup ring 20 is an annular member around the axis x, and when a contact release force P, which is a force that releases contact between the seal member 10 and the shaft 120, acts on the seal member 10 that is in contact with the shaft 120 as shown in Figure 3, the backup ring 20 contacts the seal member 10 to suppress deformation of the seal member 10. Specifically, as shown in Figure 3, when high-pressure fluid pressure (contact release force P) acts on the seal member 10 that is in contact with the shaft 120 on the side of the object to be sealed, and the inner circumferential end 10a of the seal member 10 tries to move away from the shaft 120, or when the seal member 10 deforms and the inner circumferential end 10a moves away from the shaft 120, the backup ring 20 contacts the seal member 10 to suppress deformation of the seal member 10.

[0031] Thus, the backup ring 20 is configured to contact the sealing member 10 when the sealing member 10 is deformed by the contact release force P, for example. Alternatively, the backup ring 20 is configured to contact the sealing member 10 in such a way that the sealing member 10 is not deformed by the contact release force P, for example.

[0032] Furthermore, the backup ring 20 is configured such that the sealing member 10, on which the contact release force P is not acting, does not generate a reaction force against the backup ring 20. Specifically, in the operating state, the backup ring 20 is not in contact with the sealing member 10 on which the contact release force P is not acting. Or, specifically, in the operating state, the backup ring 20 is in contact with the sealing member 10 on which the contact release force P is not acting, but no force is being applied to the sealing member 10. Or, specifically, in the operating state, the backup ring 20 is in contact with the sealing member 10 on which the contact release force P is not acting, but the contact is such that the reaction force of the sealing member 10 against the backup ring 20 is of a predetermined magnitude. This predetermined magnitude of the reaction force is, for example, such that the tightening force F1 of the sealing member 10 is within an acceptable range with respect to wear of the sealing member 10.

[0033] Furthermore, the backup ring 20 is positioned to contact the portion of the sealing member 10 that is on the outer circumference side of the tip portion 15. Alternatively, the backup ring 20 is positioned to contact the tip portion 15 of the sealing member 10. As described above, the tip portion 15 of the sealing member 10 is a part of the tip side of the inner circumference end portion 13a, including the inner circumference end 13 and its vicinity, and is the portion of the sealing member 10 that contacts the shaft 120 in the operating state.

[0034] The configuration of the backup ring 20 will be described in more detail below. Figure 4 is a partial cross-sectional perspective view showing a portion of the backup ring 20 cut along a plane parallel to axis x.

[0035] As shown in Figures 1, 2, and 4, the backup ring 20 has a base portion 21 which is an annular portion around axis x, and a support portion 22 which is an annular portion around axis x that extends from the base portion 21 toward axis x. The support portion 22 is tapered toward one side in the direction of axis x (the atmospheric side) and is inclined toward the atmospheric side.

[0036] As shown in Figures 1, 2, and 4, the base portion 21 is the part held by the holding member 30 and extends, for example, along a circle or approximately circle with axis x as its central axis or approximately central axis. The cross-sectional shape of the base portion 21 is, for example, approximately rectangular, as shown in Figures 1, 2, and 4. Note that the cross-sectional shape of the base portion 21 is not limited to the illustrated shape and may be other shapes. The base portion 21 has side surfaces 21a and 21b, which are a pair of annular surfaces facing away from each other in the direction of axis x. The base portion 21 also has an outer circumferential surface 21c and an inner circumferential surface 21d, which are a pair of annular surfaces facing away from each other in the radial direction. The side surfaces 21a and 21b extend, for example, along a plane perpendicular to axis x, and the outer circumferential surface 21c and inner circumferential surface 21d extend, for example, along a cylindrical surface with axis x as its central axis. Side surface 21a faces the object to be sealed, and side surface 21b faces the atmosphere. Furthermore, the outer circumferential surface 21c faces the outer circumferential side, and the inner circumferential surface 21d faces the inner circumferential side. The base portion 21 also has a projection portion 21e, which is an annular portion that protrudes inward from the inner circumferential surface 21d. The side surface 21a extends to the projection portion 21e.

[0037] As shown in Figures 1, 2, and 4, the support portion 22 extends inward from the protruding portion 21e of the base portion 21. The support portion 22 is inclined toward the atmosphere from the outer peripheral end 26 toward the tip portion 25. The tip portion 25 is the inner peripheral end of the support portion 22, and the outer peripheral end 26 is the outer peripheral end of the support portion 22, and is also the end that connects to the base portion 21 of the support portion 22. Furthermore, the diameter of the support portion 22 decreases toward the atmosphere in the axial x direction from the side of the object to be sealed. The support portion 22 also has a pair of annular surfaces, the contact side 23 and the opposite side 24, which are facing away from each other in the radial direction. The contact side 23 and the opposite side 24 extend between the tip portion 25 and the outer peripheral end 26.

[0038] As shown in Figures 1, 2, and 4, the contact surface 23 is a cylindrical surface that tapers in diameter from the object to be sealed towards the atmosphere in the direction of axis x, and is, for example, a conical or substantially conical cylindrical surface with axis x as the central axis or substantially the central axis. However, the contact surface 23 is not limited to a conical or substantially conical cylindrical surface. That is, the contour drawn by the contact surface 23 in a cross-section including axis x is not limited to a straight line or substantially straight line inclined with respect to axis x, but may be a curve such as an arc or circular arc projecting to the inner or outer circumference, or a line that is a combination of one or more straight lines and one or more curves. The back surface 24 is a cylindrical surface that extends along the contact surface 23, and is, for example, a conical or substantially conical cylindrical surface with axis x as the central axis or substantially the central axis. As shown in Figures 1 and 2, in cross-section, the support portion 22 is, for example, thinner towards the tip portion 25, and the back surface 24 is inclined more towards the inner circumference than the contact surface 23. Furthermore, the support portion 22 does not necessarily have to become thinner towards the tip portion 25; for example, the contact side surface 23 and the back surface 24 may be parallel, and the support portion 22 may become thicker towards the tip portion 25 in cross-section.

[0039] The backup ring 20 has the shape described above, with the tip 25 of the support portion 22 located on the innermost circumference. As an example, as shown in Figure 3, in the stopped-use state, the tip 25 of the support portion 22 of the backup ring 20 faces the portion of the inner circumference end 10a of the seal member 10 that is on the outer circumference side in the radial direction, from the outer circumference side. In other words, the length in the extension direction of the support portion 22 and the angle of the extension direction of the support portion 22 with respect to the axis x are set so that the tip 25 of the support portion 22 faces the portion of the seal member 10 that is on the outer circumference side in the radial direction, from the outer circumference side in the sealed device 1 in the stopped-use state. The stopped-use state is a state in which the tip 15 of the seal member 10 is in contact with the shaft 120 and the inner circumference end 10a is bent and deformed toward the atmosphere, and no contact release force P is acting on the seal member 10 from the side of the object to be sealed.

[0040] Furthermore, as shown in Figure 3, for example, the backup ring 20 does not contact the sealing member 10 when stopped in use. As shown in Figure 3, the tip 25 of the backup ring 20 faces the outermost portion of the tip 15 of the sealing member 10 in the radial direction, but does not contact the sealing member 10. As shown in Figure 3, in the radial direction, an annular gap G1 is formed between the tip 25 of the backup ring 20 and the back surface 12 of the sealing member 10. The radial width of the gap G1 is width W1. The width W1 of the gap G1 is set to a size such that the inner circumferential end 10a of the sealing member 10, which receives a contact release force P, undergoes a predetermined deformation. The predetermined deformation of the inner circumference end 10a includes, for example, deformation in which the tip portion 15 separates from the outer circumference surface 121 of the shaft 120, creating a gap between the sealing member 10 and the shaft 120; deformation in which the tip portion 15 maintains contact with the outer circumference surface 121 of the shaft 120, but the tightening force F1 of the sealing member 10 becomes 0 (F1=0) or approximately 0; and deformation in which the tip portion 15 maintains contact with the outer circumference surface 121 of the shaft 120, but the tightening force F1 of the sealing member 10 becomes a value within an acceptable range with respect to wear. Specifically, for example, the width W1 of the gap G1 is 0.2 mm or less. In this way, the backup ring 20 controls the deformation of the inner circumference end 10a of the sealing member 10 that receives the contact release force P during use, thereby controlling the fastening force F1 and sealing performance of the sealing member 10.

[0041] The backup ring 20 is harder than the sealing member 10. In other words, the backup ring 20 is less prone to deformation than the sealing member 10. The backup ring 20 may be highly rigid or elastic. The backup ring 20 is made of resin, for example. Examples of resin materials for the backup ring 20 include PA (polyamide), PPS (polyphenylene sulfide), TPE (thermoplastic elastomer), etc. However, the resin material for the backup ring 20 is not limited to these. Furthermore, the backup ring 20 is not limited to resin and may be formed from other materials such as metal.

[0042] As described above, the retaining member 30 is an annular member around the axis x that holds the seal portion 10 and the backup ring 20. The retaining member 30 is, for example, made of metal. However, the retaining member 30 is not limited to metal and may be formed from other materials other than metal, such as resin.

[0043] As shown in Figures 1 and 2, the retaining member 30 specifically comprises an inner retaining member 31 located on the inside and an outer retaining member 35 located on the outside. The inner retaining member 31 and the outer retaining member 35 are annular members around the axis x, and are configured to hold the sealing member 10 between them, and also to hold the sealing member 10 and the backup ring 20 overlapping each other.

[0044] As shown in Figure 2, the internal retaining member 31 has, for example, a fitting portion 32 which is an annular portion around axis x, and a retaining portion 33 which is an annular portion around axis x. The fitting portion 32 is a cylindrical portion extending along axis x, and the retaining portion 33 is a disc-shaped portion extending inward from the end of the fitting portion 12 on the side of the object to be sealed. The fitting portion 32 is, for example, cylindrical or substantially cylindrical with axis x as its central axis or substantially its central axis. The retaining portion 33 has, for example, an outer annular portion 33a which is the annular portion on the outer circumference, an inner annular portion 33b which is the annular portion on the inner circumference, and a stepped portion 33c which is a cylindrical portion extending along axis x between the outer annular portion 33a and the inner annular portion 33b.

[0045] As shown in Figure 2, the outer annular portion 33a extends inward from the end of the fitting portion 32 on the side of the object to be sealed. The stepped portion 33c is, for example, cylindrical or substantially cylindrical with axis x as its central axis or substantially as its central axis, and extends towards the atmosphere along axis x from the end of the outer annular portion 33a on the inner side. The inner annular portion 33b extends inward from the end of the stepped portion 33c on the atmosphere side. The inner annular portion 33b is located on the atmosphere side of the outer annular portion 33a, and the inner annular portion 33b and the stepped portion 33c form an annular recess that is recessed toward the atmosphere from the outer annular portion 33a.

[0046] As shown in Figure 2, the outer retaining member 35 has, for example, a fitting portion 36 which is an annular portion around axis x, and a retaining portion 37 which is an annular portion around axis x. The fitting portion 36 is a cylindrical portion extending along axis x, and the retaining portion 37 is an annular portion extending inward from the end of the fitting portion 36 on the side of the object to be sealed. The fitting portion 36 is, for example, cylindrical or substantially cylindrical with axis x as its central axis or substantially its central axis.

[0047] As shown in Figures 1 and 2, the inner retaining member 31 and the outer retaining member 35 are fitted together. Specifically, for example, the diameter of the outer peripheral surface 32a of the fitting portion 32 of the inner retaining member 31 is larger than the diameter of the inner peripheral surface 36a of the fitting portion 36 of the outer retaining member 35, and the fitting portion 32 of the inner retaining member 31 is press-fitted into the inner peripheral side of the fitting portion 36 of the outer retaining member 35, so that the fitting portion 32 of the inner retaining member 31 and the fitting portion 36 of the outer retaining member 35 are fitted together. The outer peripheral surface 32a of the fitting portion 32 is an annular surface facing the outer peripheral side of the fitting portion 32, and the inner peripheral surface 36a of the fitting portion 36 is an annular surface facing the inner peripheral side of the fitting portion 36. Furthermore, as shown in Figures 1 and 2, when the fitting portion 32 of the inner retaining member 31 and the fitting portion 36 of the outer retaining member 35 are fitted together, the retaining portion 33 of the inner retaining member 31 and the retaining portion 37 of the outer retaining member 35 have portions that face each other in the axial x direction.

[0048] For example, as shown in Figure 2, the diameter D3 of the inner circumferential end 37a, which is the inner circumferential end of the holding portion 37 of the outer holding member 35, is smaller than the diameter D2 of the inner circumferential end 33d, which is the inner circumferential end of the inner annular portion 33b of the holding portion 33 of the inner holding member 31. As a result, when the fitting portion 32 of the inner holding member 31 and the fitting portion 36 of the outer holding member 35 are fitted together, the entire holding portion 33 of the inner holding member 31 faces the holding portion 37 of the outer holding member 35 in the axial x direction. On the other hand, the inner circumferential end 37b of the holding portion 37 of the outer holding member 35 and a portion extending from the inner circumferential end 37b are located radially inward from the inner circumferential end 33b of the holding portion 33 of the inner holding member 31. Note that the diameter D3 of the inner circumferential end 37a of the holding portion 37 of the outer holding member 35 and the diameter D2 of the inner circumferential end 33d of the holding portion 33 of the inner holding member 31 may be the same. Also, the diameter D3 of the inner circumferential end 37a of the holding portion 37 of the outer holding member 35 may be larger than the diameter D2 of the inner circumferential end 33d of the holding portion 33 of the inner holding member 31.

[0049] Furthermore, as shown in Figures 1 and 2, when the inner retaining member 31 and the outer retaining member 35 are fitted together, the outer annular portion 33a of the retaining portion 33 of the inner retaining member 31 and the retaining portion 37 of the outer retaining member 35 face each other in the axial x direction, with the outer peripheral end 10b, which is the outer peripheral end of the seal member 10, in between. Specifically, the back surface 12 of the outer peripheral end 10b of the seal member 10 faces the outer annular portion 33a of the retaining portion 33 of the inner retaining member 31, and the contact surface 11 of the outer peripheral end 10b of the seal member 10 faces the retaining portion 37 of the outer retaining member 35, so that the seal member 10 is sandwiched between the outer annular portion 33a and the retaining portion 37 of the retaining portion 33.

[0050] Also, as shown in FIGS. 1 and 2, in a state where the inner holding member 31 and the outer holding member 35 are fitted to each other, the inner annular portion 33b of the holding portion 33 of the inner holding member 31 and the holding portion 37 of the outer holding member 35 face each other in the axial direction x with the seal member 10 and the backup ring 20 overlapped with each other in the axial direction x. In the sealing device 1, as shown in FIG. 2, the seal member 10 is overlapped with the backup ring 20 at the intermediate portion 10c. The backup ring 20 is located on the atmosphere side in the axial direction x with respect to the seal member 10, and the back surface 12 at the intermediate portion 10c of the backup ring 20 and the side surface 21a of the backup ring 20 are in contact with each other. The intermediate portion 10c of the seal member 10 is a portion between the inner peripheral end portion 10a and the outer peripheral end portion 10b of the seal member 10. Specifically, the side surface 21b of the base portion 21 of the backup ring 20 faces the inner annular portion 33b of the holding portion 33 of the inner holding member 31, and the contact side surface 11 at the intermediate portion 10c of the seal member 10 faces the holding portion 37 of the outer holding member 35, and the seal member 10 and the backup ring 20 are sandwiched between the inner annular portion 33b of the holding portion 33 and the holding portion 37. Also, specifically, in the holding portion 33 of the inner holding member 31, the distance L1 in the axial direction x between the side surface 33e, which is the surface on the sealing object side of the outer annular portion 33a, and the side surface 33f, which is the surface on the sealing object side of the inner annular portion 33b, is smaller than the width W2 of the backup ring 20 (L1 < W2). The width W2 of the backup ring 20 is the width of the base portion 21 of the backup ring 20 in the axial direction x and is the distance between the side surface 21a and the side surface 21b in the axial direction x.

[0051] As shown in Figures 1 and 2, when the inner retaining member 31 and the outer retaining member 35 are fitted together and the sealing member 10 and the backup ring 20 are sandwiched between the inner retaining member 31 and the outer retaining member 35, the inner circumferential end 10a of the sealing member 10 is positioned on the inner side of the inner circumferential end 37b of the retaining portion 37 of the outer retaining member 35. Also, as shown in Figures 1 and 2, when the inner retaining member 31 and the outer retaining member 35 are fitted together and the sealing member 10 and the backup ring 20 are sandwiched between the inner retaining member 31 and the outer retaining member 35, the tip 25 of the support portion 22 of the backup ring 20 is positioned on the inner side of the inner circumferential end 33d of the inner annular portion 33b of the retaining portion 33 of the inner retaining member 31.

[0052] Furthermore, as described above, in the stopped-operation state, the tip 25 of the support portion 22 of the backup ring 20 is positioned radially opposite to the portion on the outer circumference side of the tip 15 of the inner circumference end 10a of the seal member 10, from the outer circumference side. Also, in the stopped-operation state, a gap G1 is formed radially between the tip 25 of the backup ring 20 and the back surface 12 of the seal member 10. For this reason, as shown in Figures 1 and 2, when the inner holding member 31 and the outer holding member 35 are fitted together and the seal member 10 and backup ring 20 are sandwiched between the inner holding member 31 and the outer holding member 35, the inner circumference end 13 of the seal member 10 is positioned on the inner circumference side of the tip 25 of the support portion 22 of the backup ring 20. In other words, in the sealing device 1, the sealing member 10 extends inward from the support portion 22 of the backup ring 20, and the diameter D1 of the inner end 13 of the sealing member 10 is smaller than the diameter D4 of the tip portion 25 of the support portion 22 of the backup ring 20. Furthermore, in the stopped operating state, the diameter D1 of the inner end 13 of the sealing member 10 and the diameter D4 of the tip portion 25 of the support portion 22 of the backup ring 20 are set such that the tip portion 25 of the support portion 22 of the backup ring 20 faces radially from the outer side of the portion of the support portion 22 of the sealing member 10 that is on the outer side of the tip portion 15 of the inner end 10a of the sealing member 10.

[0053] As shown in Figure 2, the inner retaining member 31 and the outer retaining member 35 are fitted together, and the sealing member 10 is pressed in the axial x direction by being sandwiched between the outer annular portion 33a of the retaining portion 33 of the inner retaining member 31 and the retaining portion 37 of the outer retaining member 35 at its outer peripheral end 10b. Also, the overlapping sealing member 10 and backup ring 20 are pressed in the axial x direction by being sandwiched between the inner annular portion 33b of the retaining portion 33 of the inner retaining member 31 and the retaining portion 37 of the outer retaining member 35 at their intermediate portion 10c and root portion 21, respectively. A pressing portion 38 is formed on the fitting portion 36 of the outer retaining member 35, and the inner retaining member 31 is fixed to the outer retaining member 35. The pressing portion 38 of the outer retaining member 35 is the part that contacts the fitting portion 32 of the inner retaining member 31 and fixes the fitting portion 32 in the axial x direction. The retaining portion 38 may be formed in advance, or it may be formed by crimping or the like after the fitting portion 32 and the fitting portion 36 are fitted together. In this way, the overlapping sealing member 10 and the backup ring 20 are fixed between the inner holding member 31 and the outer holding member 35 (hereinafter also referred to as the "assembled state").

[0054] Each component of the sealing device 1 has the configuration described above, and when assembled, it becomes the sealing device 1 shown in Figures 1 and 2. In the sealing device 1, the fitting portion 32 of the inner holding member 31 is fitted into the fitting portion 36 of the outer holding member 35, and the fitting portion 32 of the inner holding member 31 is pushed toward the front by the pressing portion 38 of the fitting portion 36 of the outer holding member 35. The seal member 10 is sandwiched at its outer peripheral end 10b between the outer annular portion 33a of the holding portion 33 of the inner holding member 31 and the holding portion 37 of the outer holding member 35. The backup ring 20 is superimposed on the intermediate portion 10c of the seal member 10 from the atmospheric side and sandwiched between the inner annular portion 33b of the holding portion 33 of the inner holding member 31 and the holding portion 37 of the outer holding member 35. Furthermore, the outer circumferential surface 21c of the base portion 21 of the backup ring 20 is in contact with the stepped portion 33b of the inner holding member 31 and is supported in the radial direction. In this way, the inner holding member 31 is fixed to the outer holding member 35, and the seal member 10 and the backup ring 20 are held and fixed between the inner holding member 31 and the outer holding member 35. The seal member 10 also extends inward so as to contact the shaft 120 when stopped and in use. In addition, when stopped and in use, the support portion 22 of the backup ring 20 extends such that the tip portion 25 of the support portion 22 of the backup ring 20 faces the portion of the inner circumferential end portion 10a of the seal member 10 from the outer circumferential side in the radial direction, relative to the tip portion 15 of the inner circumferential end portion 10a of the seal member 10. Furthermore, the width W1 of the gap G1 between the tip portion 25 of the backup ring 20 and the back surface 12 of the seal member 10 is such that the inner circumferential end portion 10a of the seal member 10, upon receiving the contact release force P, undergoes the predetermined deformation described above. The width W1 of the gap G1 is set based on, for example, the diameter D1 and thickness T1 of the sealing member 10, the diameter D4 of the support portion 22 of the backup ring 20, and the position of the tip portion 25 of the support portion 22.

[0055] Next, the operation of the sealing device 1 will be explained. As shown in Figure 3, the sealing device 1 is installed between the through hole 111 of the housing 110 of the air compressor 100 and the shaft 120 to enter the operating state. Specifically, the fitting portion 36 of the outer holding portion 35 of the holding member 30 is fitted into the through hole 111, fixing the sealing device 1 to the housing 110, and the shaft 120 is passed through the inner circumferential end 13 of the sealing member 10 from the side of the object to be sealed, so that the sealing device 1 enters the stopped operating state. In the stopped operating state, the inner circumferential end 10a of the sealing member 10 is bent and deformed toward the atmosphere, and the tip portion 15 is in contact with the outer circumferential surface 121 of the shaft 120. In this way, the fitting portion 36 of the holding member 30 is fitted into and in contact with the through hole 111, and the tip portion 15 of the sealing member 10 is in contact with the shaft 120, thus sealing the object to be sealed.

[0056] As described above, as shown in Figure 3, in the stopped operating state, the tip 25 of the support portion 22 of the backup ring 20 faces the portion of the inner circumference end 10a of the sealing member 10 that is on the outer circumference side, radially from the outer circumference side. In addition, a gap G1 with a radial width W1 is formed between the tip 25 of the backup ring 20 and the back surface 12 of the sealing member 10.

[0057] As the shaft 120 rotates, the fluid to be sealed on the object being sealed side, such as air, is compressed. This causes the sealing device 1 to change from a stopped state to a driven state. In the driven state, the fluid to be sealed on the object being sealed side is compressed, the space on the object being sealed side becomes high pressure, and pressure acts on the sealing member 10 from the object being sealed side. In the driven state, as the rotation of the shaft 120 increases, the space on the object being sealed side becomes even higher pressure, and when the pressure in the space on the object being sealed side becomes high enough to exert a contact release force P on the inner circumferential end 10a of the sealing member 10, the inner circumferential end 10a of the sealing member 10 begins to deform away from the shaft 120. Then, as the inner circumferential end 10a deforms further due to the contact release force P, the width of the gap G1 decreases, and as the back surface 12 of the inner circumferential end 10a moves radially toward the tip 25 of the support portion 22 of the backup ring 20 by a distance of width W1, the tip 25 of the backup ring 20 comes into contact with the sealing member 10. As a result, even if the space on the side of the object being sealed becomes more high pressure and the contact release force P acting on the inner circumferential end 10a of the sealing member 10 becomes even larger, further deformation of the inner circumferential end 10a is prevented or suppressed.

[0058] Figure 5 is a partial cross-sectional view showing an example of a state in which the tip 25 of the backup ring 20 is in contact with the inner circumferential end 10a of the seal member 10 in the driving operation state. As shown in Figure 5, as an example, in the state in which the tip 25 of the backup ring 20 is in contact with the inner circumferential end 10a of the seal member 10 (hereinafter also referred to as the contact state), the tip 15 maintains contact with the outer circumferential surface 121 of the shaft 120. Furthermore, although the tip 15 maintains contact with the outer circumferential surface 121 of the shaft 120, the clamping force F1 of the seal member 10 is 0 (F1=0) or approximately 0. Therefore, even if the space on the side of the object to be sealed becomes more high pressure and the seal member 10 deforms, the sealing performance of the seal member 10 maintains the sealing performance in the stopped operation state, or the decrease in the sealing performance of the seal member 10 from the sealing performance in the stopped operation state is suppressed. On the other hand, wear of the seal member 10 at high rotation speeds of the shaft 120 is reduced.

[0059] Furthermore, at low rotational speeds of the shaft 120 before the sealing member 10 makes contact, the backup ring 20 is not in contact with the sealing member 10, and the fastening force F1 of the sealing member 10 is not due to the force applied by the backup ring 20. For this reason, at low rotational speeds of the shaft 120, the amount of wear on the sealing member 10 due to the backup ring 20 does not increase.

[0060] Figure 6 is a partial cross-sectional view showing another example of the contact state of the seal member 10 in the driving operation state. As shown in Figure 6, as an example, in the contact state of the seal member 10, the tip portion 15 maintains contact with the outer circumferential surface 121 of the shaft 120. Furthermore, although the clamping force F1 of the seal member 10 is greater than 0, it is within an acceptable range in terms of wear of the seal member 10. Therefore, even if the space on the side of the object to be sealed becomes more high pressure and the seal member 10 deforms, the sealing performance of the seal member 10 maintains the sealing performance in the stopped operation state, or the decrease in the sealing performance of the seal member 10 from the sealing performance in the stopped operation state is suppressed. On the other hand, wear of the seal member 10 at high rotation speeds of the shaft 120 is reduced.

[0061] Furthermore, at low rotational speeds of the shaft 120 before the sealing member 10 makes contact, the backup ring 20 is not in contact with the sealing member 10, and the fastening force F1 of the sealing member 10 is not due to the force applied by the backup ring 20. For this reason, at low rotational speeds of the shaft 120, the amount of wear on the sealing member 10 due to the backup ring 20 does not increase.

[0062] Figure 7 is a partial cross-sectional view showing another example of the contact state of the seal member 10 in the driving operation state. As shown in Figure 7, as an example, in the contact state of the seal member 10, the tip portion 15 is not in contact with the outer circumferential surface 121 of the shaft 120. In the contact state of the seal member 10, an annular gap, or gap G2, is formed between the tip portion 15 and the outer circumferential surface 121 of the shaft 120. The radial width of the gap G2 is W3. The width W3 is very small. The tip portion 15 of the seal member 10 is separated from the outer circumferential surface 121 of the shaft 120 before the seal member 10 comes into contact. Therefore, the seal member 10 does not wear down when the shaft 120 is rotating at high speeds. On the other hand, although the sealing performance of the seal member 10 decreases when the shaft 120 is rotating at high speeds, by making the width W3 of the formed gap G2 very small, the decrease in the sealing performance of the seal member 10 from the sealing performance in the stopped operation state is suppressed.

[0063] Furthermore, at low rotational speeds of the shaft 120 before the sealing member 10 makes contact, the backup ring 20 is not in contact with the sealing member 10, and the fastening force F1 of the sealing member 10 is not due to the force applied by the backup ring 20. For this reason, at low rotational speeds of the shaft 120, the amount of wear on the sealing member 10 due to the backup ring 20 does not increase.

[0064] As described above, the backup ring 20 can control the deformation of the sealing member 10 when a contact release force P is applied to the sealing member 10, thereby suppressing or preventing wear of the sealing member 10, and also suppressing or preventing a decrease in the sealing performance of the sealing member 10.

[0065] Thus, according to the sealing device 1 of the present invention, it is possible to suppress wear of the sealing member 10 while suppressing a decrease in sealing performance.

[0066] Next, a first modified example of the sealing device 1 according to an embodiment of the present invention will be described. Figure 8 is a partially enlarged cross-sectional view showing the sealed device 1 according to the first modified example in a stopped-use state. As shown in Figure 8, in the sealed device 1 according to the first modified example, in the stopped-use state, the tip 25 of the support portion 22 of the backup ring 20 is in contact with the back surface 12 of the inner circumference end portion 10a of the sealing member 10. The tip 25 of the backup ring 20 is in contact with the portion of the inner circumference end portion 10a of the sealing member 10 that is on the inner circumference side than the tip 15.

[0067] For example, in a stopped-operation state, the tip 15 of the backup ring 20 is in contact with the sealing member 10, but no force is being applied to the sealing member 10. In other words, in a stopped-operation state, the fastening force F1 of the sealing member 10 is not due to the force applied by the backup ring 20. Therefore, in a stopped-operation state, the amount of wear on the sealing member 10 due to the backup ring 20 does not increase.

[0068] Furthermore, in the first modified example, the sealing member 10 is in contact with the seal member 10 from the stopped operating state, and even when the seal member 10 receives a contact release force P in the driven operating state, deformation of the seal member 10 is prevented or suppressed. For this reason, even in the driven operating state, the tip portion 15 of the backup ring 20 is in contact with the seal member 10, but no force is applied to the seal member 10, and the fastening force F1 of the seal member 10 does not change from the stopped operating state. Alternatively, in the driven operating state, the inner circumferential end portion 10a of the seal member 10 undergoes a small deformation, and as a result, for example, the fastening force F1 of the seal member 10 is slightly reduced.

[0069] Thus, in this example of the sealing device 1 according to the first modification, even if the space on the side of the object to be sealed becomes high pressure, the sealing performance of the sealing member 10 maintains the sealing performance in the stopped operating state, or the decrease in the sealing performance of the sealing member 10 from the sealing performance in the stopped operating state is suppressed. On the other hand, the fastening force F1 of the sealing member 10 when the shaft 120 is rotating at high pressure is maintained at the fastening force F1 in the stopped operating state, or is reduced to the fastening force F1 in the stopped operating state. Therefore, even if the space on the side of the object to be sealed becomes high pressure, the sealing performance of the sealing member 10 maintains the sealing performance in the stopped operating state, or the decrease in the sealing performance of the sealing member 10 from the sealing performance in the stopped operating state is suppressed. On the other hand, the increase in wear of the sealing member 10 when the shaft 120 is rotating at high pressure is prevented or reduced.

[0070] As another example, in the stopped-use state, the tip 15 of the backup ring 20 is in contact with the sealing member 10, but the contact is such that the reaction force of the sealing member 10 against the backup ring 20 is of a predetermined magnitude. This predetermined magnitude of reaction force is, for example, such that the tightening force F1 of the sealing member 10 is within an acceptable range with respect to wear of the sealing member 10. In other words, in the stopped-use state, the fastening force F1 of the sealing member 10 is the force applied from the backup ring 20. However, this fastening force F1 is within an acceptable range of fastening force, and in the stopped-use state, the amount of wear of the sealing member 10 is prevented or suppressed from exceeding the acceptable range.

[0071] Furthermore, in the first modified example, the sealing member 10 is in contact with the sealing member 10 from the stopped operating state, and even when the sealing member 10 receives a contact release force P in the driven operating state, deformation of the sealing member 10 is prevented or suppressed. For this reason, even in the driven operating state, the tip portion 15 of the backup ring 20 is in contact with the sealing member 10. Also, in this example, the backup ring 20 applies force to the sealing member 10, but the fastening force F1 increased by the force from the backup ring 20 is within the range of the allowable fastening force. Alternatively, in the driven operating state, the inner circumference end portion 10a of the sealing member 10 undergoes slight deformation, and as a result, for example, the fastening force F1 of the sealing member 10 is slightly reduced.

[0072] Thus, in this example of the sealing device 1 according to the first modification, even if the space on the side of the object to be sealed becomes high pressure, the sealing performance of the sealing member 10 maintains the sealing performance in the stopped operating state, or the decrease in the sealing performance of the sealing member 10 from the sealing performance in the stopped operating state is suppressed. On the other hand, the fastening force F1 of the sealing member 10 when the shaft 120 is rotating at high pressure is maintained at the fastening force F1 in the stopped operating state, or is reduced to the fastening force F1 in the stopped operating state. Therefore, even if the space on the side of the object to be sealed becomes high pressure, the sealing performance of the sealing member 10 maintains the sealing performance in the stopped operating state, or the decrease in the sealing performance of the sealing member 10 from the sealing performance in the stopped operating state is suppressed. On the other hand, the increase in wear of the sealing member 10 when the shaft 120 is rotating at high pressure is prevented or reduced. Furthermore, even if the fastening force F1 increases due to the force from the backup ring 20, the fastening force F1 will be within the range of the allowable fastening force, and excessive wear of the sealing member 10 is prevented or suppressed.

[0073] Next, a second modified example of the sealing device 1 according to an embodiment of the present invention will be described. Figure 9 is a partially enlarged cross-sectional view showing the sealing device 1 according to the second modified example in a stopped-use state. As shown in Figure 9, in the sealing device 1 according to the second modified example, in the stopped-use state, the tip 25 of the support portion 22 of the backup ring 20 faces the tip 15 of the inner circumferential end portion 10a of the sealing member 10 with a gap G1 in the radial direction. The sealing device 1 according to the second modified example also operates in the same manner as the sealing device 1 according to the embodiment of the present invention described above, and produces the same effects.

[0074] Next, a third modified example of the sealing device 1 according to an embodiment of the present invention will be described. Figure 10 is a partially enlarged cross-sectional view showing the sealing device 1 according to the third modified example in a stopped-use state. As shown in Figure 10, in the sealing device 1 according to the third modified example, in the stopped-use state, the tip 25 of the support portion 22 of the backup ring 20 is radially opposite the tip 15 of the inner circumferential end portion 10a of the sealing member 10. Also, the tip 25 of the backup ring 20 is in contact with the back surface 12 of the inner circumferential end portion 10a of the sealing member 10. The sealing device 1 according to the third modified example operates in the same manner as the sealing device 1 according to the first modified example described above and produces the same effects.

[0075] Although the present invention has been described above through the embodiments described above, the technical scope of the present invention is not limited to the scope described in the embodiments above. It will be obvious to those skilled in the art that various modifications or improvements can be made to the embodiments described above. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.

[0076] The embodiments described above are for the purpose of facilitating understanding of the present invention and are not intended to limit its interpretation. Furthermore, the embodiments described above do not limit the scope of application of the present invention, and the present invention may encompass anything as its target application. The components of the above embodiments, as well as their arrangement, materials, conditions, shapes, and sizes, are not limited to those exemplified and can be modified as appropriate. For example, the present invention includes differences that arise in the implementation of manufacturing tolerances, etc. Furthermore, components shown in different embodiments can be partially substituted or combined to the extent that they do not contradict each other in a technical sense. In addition, each configuration can be selectively combined as appropriate to achieve at least some of the problems and effects described above.

[0077] For example, the shape of the base portion 21 of the backup ring 20 is not limited to the shape described above. Also, the shape of the inner annular portion 33b and the stepped portion 33c of the holding portion 33 of the inner holding member 31 is not limited to the shape described above. The shape of the base portion 21 of the backup ring 20, and the shape of the inner annular portion 33b and the stepped portion 33c of the inner holding member 31, may be any shape that holds the backup ring 20, as described above. The shape of the base portion 21 of the backup ring 20, and the shape of the inner annular portion 33b and the stepped portion 33c of the inner holding member 31 may be, for example, the shapes shown in Figures 11 and 12.

[0078] Furthermore, the backup ring 20 is not limited to contacting the sealing member 10 at its tip 25, but may also contact it at other points. For example, the backup ring 20 may contact the sealing member 10 at a contact surface 23 on the outer peripheral end 26 side of the tip 25. Also, the backup ring 20 may contact the sealing member 10 at multiple points. For example, part or all of the contact surface 23 of the backup ring 20 may be shaped to conform to part or all of the back surface 12 of the inner peripheral end 10a of the sealing member 10 in the stopped operating state, and may contact part or all of the back surface 12 of the sealing member 10. Also, for example, part or all of the contact surface 23 of the backup ring 20 may be shaped to conform to part or all of the back surface 12 of the inner peripheral end 10a of the sealing member 10 when it is deformed in the driven operating state, and may contact part or all of the back surface 12 of the sealing member 10. Furthermore, the backup ring 20 is not limited to an endless annular shape, but may be a substantially tubular (arc-shaped) shape with a slit, or a ring formed by multiple arc-shaped or circular arc-shaped parts spaced apart and arranged circumferentially. Also, for example, only the support portion 22 of the backup ring 20 may be a substantially tubular shape with a slit, or a ring formed by multiple arc-shaped or circular arc-shaped parts spaced apart and arranged circumferentially. [Explanation of symbols]

[0079] 1 Sealing device, 10 Sealing member, 10a Inner circumferential end, 10b Outer circumferential end, 10c Middle part, 11 Contact side, 12 Back, 13 Inner circumferential end, 14 Outer circumferential end, 15 Tip, 20 Backup ring, 21 Base, 21a, 21b Side, 21c Outer circumferential surface, 21d Inner circumferential surface, 21e Protruding part, 22 Support part, 23 Contact side, 24 Back, 25 Tip, 26 Outer circumferential end, 30 Support member, 31 Inner holding member, 32 Fitting part, 32a Outer circumferential surface, 33 Holding part, 33a Outer ring part, 33b Inner ring part, 33c Stepped part, 33d Inner circumferential end, 33e, 33f Side, 35 Outer holding member, 36 Fitting part, 36a Inner circumferential surface, 37 Holding part, 37b Inner circumference, 100 Air compressor, 110 Housing, 111 Through hole, 120 Shaft, 121 Outer circumference, D1, D2, D3, D4 Diameter, F1 Clamping force, G1, G2 Gap, L1 Distance, P Contact release force, T1 Thickness, W1, W2, W3 Width, x Axis

Claims

1. A sealing device for sealing the annular gap between a through hole and a shaft passing through the through hole, A sealing member which is an annular member around the axis, A backup ring, which is an annular member, is positioned around the aforementioned axis. The system comprises a retaining member which is an annular member around the axis that holds the sealing member and the backup ring, The sealing member is configured to contact the shaft at its inner circumference end, The backup ring is configured to contact the sealing member when a force that releases the contact is applied to the sealing member that is in contact with the shaft. Sealing device.

2. The backup ring is configured to contact the sealing member when the sealing member is deformed by the force. The sealing device according to claim 1.

3. The backup ring is positioned to contact the sealing member so that the sealing member does not deform due to the force. The sealing device according to claim 1.

4. The backup ring is in contact with the sealing member, which is not subjected to the aforementioned force, such that it generates a reaction force of a predetermined magnitude relative to the backup ring. A sealing device according to any one of claims 1 to 3.

5. The backup ring is configured such that the sealing member on which the force is not acting does not generate a reaction force against the backup ring. A sealing device according to any one of claims 1 to 3.

6. The backup ring is configured to contact the tip end of the inner circumference end of the sealing member. The sealing device according to claim 1.

7. The backup ring is configured to contact the portion of the inner end of the sealing member that is on the outer side rather than the tip end. The sealing device according to claim 1.

8. The backup ring is provided on one side in the axial direction relative to the sealing member. The sealing device according to claim 1.

9. The backup ring has a base portion which is an annular part, and a support portion which is an annular part extending from the base portion toward the axis, The support portion is tapered toward one side in the axial direction. The sealing device according to claim 1.

10. The tip end of the support portion of the backup ring is deformed to one side in the axial direction, and the tip end of the inner circumference end of the sealing member, whose inner circumference end is in contact with the shaft, is facing the outer circumference end in the radial direction. The sealing device according to claim 9.

11. The tip end of the support portion of the backup ring is deformed to one side in the axial direction, and the portion of the inner circumference end of the sealing member that is in contact with the shaft is radially opposed to the outer circumference side of the inner circumference end of the sealing member, which is further outward than the tip end. The sealing device according to claim 9.

12. The backup ring is harder than the sealing member. The sealing device according to claim 1.

13. The backup ring is elastic, The sealing device according to claim 12.

Images