Sealing device

Abstract

The present application provides a sealing device which can stably exert a sealing function even in the case where the rotational speed of a rotating shaft is high. A sealing device (10) is characterized by being a device that seals an annular gap between a rotating shaft (50) and a cover (60) having a shaft hole into which the rotating shaft (50) is inserted, and the sealing device includes: a housing (100) that is fixed with respect to the shaft hole; and a seal ring (200) that is configured to be held on the housing (100) in a state in which movement in a rotational direction is limited inside the housing (100) and separates a high-pressure side (H) that is high in pressure during use of the device and a low-pressure side (L) on the opposite side thereof, the seal ring (200) being provided in a state in which an annular gap is provided between an outer peripheral surface of the rotating shaft (50), and the annular gap being set by a size at which a Lomakin effect is achieved by a fluid pressure of a sealing object fluid that enters from the high-pressure side (H) toward the low-pressure side (L).

Description

Technical Field

[0001] This invention relates to a sealing device for sealing the annular gap between a rotating shaft and a cover. Background Technology

[0002] Typically, sealing devices that seal the annular gap between a rotating shaft and a cover include a sealing ring or similar device that makes contact while sliding on the rotating shaft. However, such contact-type sealing devices have a limited range of coverage for the rotational speed of the rotating shaft.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 2662720 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] The purpose of this invention is to provide a sealing device that can stably perform its sealing function even when the rotational speed of the rotating shaft is high.

[0008] Solution for solving the problem

[0009] To address the aforementioned issues, the present invention employs the following solution.

[0010] That is, the sealing device of the present invention is characterized in that it seals the annular gap between the rotating shaft and the cover having a shaft hole for insertion of the rotating shaft.

[0011] The sealing device has the following features:

[0012] A housing, which is fixed relative to the shaft hole;

[0013] A sealing ring is configured to be held on the housing within the housing in a state of restricted movement in the rotational direction, and to separate the high-pressure side (where the device operates under high pressure) from the low-pressure side (where the device operates under high pressure).

[0014] The sealing ring is configured with an annular gap between it and the outer circumferential surface of the rotating shaft, and the size of the annular gap is set by the fluid pressure of the sealing fluid entering from the high-pressure side to the low-pressure side to achieve the Lomakin effect.

[0015] According to the present invention, an annular gap is provided between the sealing ring and the outer peripheral surface of the rotating shaft, and an alignment effect can be obtained between the rotating shaft and the sealing ring through the Lomakin effect, thus the annular gap can remain stable. This prevents the sealing ring from contacting (slipping) with the rotating shaft. Furthermore, the annular gap, set according to the size required to achieve the Lomakin effect, can be made into a very small gap, thus enabling a sealing function.

[0016] Preferably, at least one of the following is provided on the inner circumferential surface of the sealing ring: a labyrinth groove with a labyrinth sealing structure and a screw pump groove that functions as a screw pump, wherein the screw pump function refers to the function of the sealed fluid entering the annular gap returning towards the high-pressure side.

[0017] Therefore, combined with the alignment effect described above, the sealing function can be stably maintained. Moreover, as mentioned above, stability is maintained through the annular gap, thereby suppressing the influence of the rotational speed of the rotating shaft on the sealing function.

[0018] Preferably, the inner circumferential surface of the sealing ring has a cylindrical surface region composed of cylindrical surfaces, and at least one of the labyrinth groove and the screw pump groove is disposed closer to the low-pressure side than the cylindrical surface region. Furthermore, the inner diameter of the cylindrical surface region can be set to be the same as or different from the inner diameter of the region where the labyrinth groove and the screw pump groove are provided.

[0019] By setting up such a cylindrical region, the Lomakin effect (alignment effect) can be performed more reliably and stably.

[0020] Preferably, the sealing device further comprises:

[0021] A vibration damping ring is provided within the housing, having an annular gap between itself and the rotating shaft, and is positioned closer to the low-pressure side than the sealing ring, and is held on the housing in contact with the sealing ring;

[0022] An elastic ring that seals the annular gap between the housing and the vibration damping ring, and holds the vibration damping ring onto the housing; and

[0023] The pressing component presses the sealing ring toward the vibration-suppressing ring.

[0024] By employing this configuration, friction is generated between the sealing ring and the vibration-damping ring when the rotating shaft vibrates, and due to the alignment effect, the sealing ring moves radially, thereby suppressing the movement of the sealing ring. Thus, the alignment effect of the sealing ring suppresses the vibration of the rotating shaft itself. Furthermore, the vibration-damping ring is held by an elastic ring, and the vibration absorption effect of the elastic ring suppresses the vibration of each component. Moreover, by pressing the sealing ring against the vibration-damping ring, the formation of a gap between the sealing ring and the vibration-damping ring is prevented, thereby suppressing leakage of the fluid from the sealed area.

[0025] Preferably, the sealing ring is made of a material with lower hardness compared to the vibration damping ring. For example, it is suitable for the sealing ring to be made of carbon material, and the vibration damping ring to be made of metal or ceramic material.

[0026] In addition, it is also suitable to have a retaining member that is mounted on the housing and holds the pressing member.

[0027] Furthermore, the above components can be combined and used as much as possible.

[0028] Invention Effects

[0029] As explained above, according to the present invention, the sealing function can still be stably performed even when the rotational speed of the rotating shaft is high. Attached Figure Description

[0030] Figure 1 This is a partially disconnected cross-sectional view of the sealing device according to Embodiment 1 of the present invention.

[0031] Figure 2 This is a schematic cross-sectional view of the sealing structure according to Embodiment 1 of the present invention.

[0032] Figure 3 This is a schematic cross-sectional view of the sealing device according to Embodiment 1 of the present invention.

[0033] Figure 4 This is a partially disconnected cross-sectional view of the sealing device according to Embodiment 2 of the present invention.

[0034] Figure 5 This is a schematic cross-sectional view of the sealing structure according to Embodiment 2 of the present invention.

[0035] Figure 6 This is a front view of the sealing device according to Embodiment 3 of the present invention.

[0036] Figure 7 This is a schematic cross-sectional view of the sealing device according to Embodiment 3 of the present invention. Detailed Implementation

[0037] The following detailed description of methods for implementing the present invention is based on the accompanying drawings and exemplary embodiments. However, unless otherwise stated, the dimensions, materials, shapes, relative arrangements, etc., of the constituent components described in this embodiment are not intended to limit the scope of the invention.

[0038] (Example 1)

[0039] Reference Figures 1-3 The sealing device according to Embodiment 1 of the present invention will be described. Figure 1 This is a partially disconnected cross-sectional view of the sealing device according to Embodiment 1 of the present invention. The upper side of the figure shows a cross-sectional view of the sealing device after a portion of the surface including the central axis of the sealing device has been cut off, as viewed from the outer peripheral surface of the sealing device. Figure 2 This is a schematic cross-sectional view of the sealing structure according to Embodiment 1 of the present invention. With respect to the sealing device, a cross-sectional view is shown after cutting the sealing device on the surface including the central axis. Figure 3 This is a schematic cross-sectional view of the sealing device according to Embodiment 1 of the present invention, showing a cross-sectional view after the sealing device has been cut off on a surface perpendicular to the aforementioned central axis. Furthermore, the sealing device is rotationally symmetric, with a few exceptions.

[0040] <Sealing Structure>

[0041] Especially refer to Figure 2 The sealing structure using the sealing device described in this embodiment will be described. The sealing structure of this embodiment includes: a rotating shaft 50, a cover 60 having a shaft hole for insertion of the rotating shaft 50, and a sealing device 10 for sealing the annular gap between the rotating shaft 50 and the cover 60. The sealing device 10 is configured to be fixed to the cover 60 and have a gap between it and the rotating shaft 50. By separating the annular gap between the rotating shaft 50 and the cover 60 using the sealing device 10, leakage of the fluid to be sealed can be suppressed. Furthermore, in Figure 2 In this embodiment, the fluid to be sealed is sealed on the left side relative to the sealing device 10, and the device operates at high pressure. Hereinafter, the left side relative to the sealing device 10 will be referred to as the high-pressure side (H), and the opposite side (right side) will be referred to as the low-pressure side (L). Furthermore, the sealing device 10 described in this embodiment can be appropriately used, for example, as a gas seal (where the fluid to be sealed is high-pressure gas) in automotive parts.

[0042] <Sealing device>

[0043] The sealing device 10 according to this embodiment will be described in more detail. The sealing device 10 includes: a housing 100; a sealing ring 200 and a vibration damping ring 300 held on the housing 100; an elastic ring 400 for holding the vibration damping ring 300 on the housing 100; and a coil spring 500, which serves as a pressing member for pressing the sealing ring 200 toward the vibration damping ring 300. The sealing ring 200 is made of a material with lower hardness than the vibration damping ring 300.

[0044] The housing 100 is a ring-shaped component made of metal or the like. The housing 100 includes a large-diameter portion 110 that is fixed to the inner circumferential surface of the shaft hole of the cover 60 by pressing or the like; and a small-diameter portion 120 that is located further down the low-pressure side (L) than the large-diameter portion 110 and has a smaller outer diameter than the large-diameter portion 110. Furthermore, an inward flange portion 111 is provided at the end of the large-diameter portion 110, and a protrusion 112 for preventing rotation and limiting the movement of the sealing ring 200 in the rotational direction is provided at least at one location in the circumferential direction of the large-diameter portion 110. Also, an inward flange portion 121 is provided at the end of the small-diameter portion 120.

[0045] The sealing ring 200 is a ring-shaped component made of carbon material or the like. An annular protrusion 210 protruding radially outward is provided on the outer circumferential surface of the sealing ring 200. At least one location on the circumferential surface of the annular protrusion 210 is provided with a recess 211 into which a protrusion 112 provided on the housing 100 is pressed. Thus, by the protrusion 112 pressing into the recess 211, the rotational movement of the sealing ring 200 can be restricted. Furthermore, in... Figure 3 The figure shows a cross-sectional view of the portion where the protrusion 112 is inserted into the recess 211. This figure shows a configuration where the protrusion 112 and the recess 211 are provided at only one location in the circumferential direction. However, multiple protrusions and recesses can also be provided in the circumferential direction.

[0046] The sealing ring 200 is configured with an annular gap between it and the outer peripheral surface of the rotating shaft 50. This annular gap is determined by the size of the Lomakin effect achieved by the fluid pressure of the sealing fluid entering from the high-pressure side (H) to the low-pressure side (L). Furthermore, a cylindrical surface region 220, composed of cylindrical surfaces, is provided on the inner peripheral surface of the sealing ring 200. This cylindrical surface region 220 is located on the high-pressure side (H) of the inner peripheral surface of the sealing ring 200. Moreover, at least one groove 230 is provided on the inner peripheral surface of the sealing ring 200, closer to the low-pressure side (L) than the cylindrical surface region 220. Additionally, although... Figure 1 , 2The inner diameter of the portion between adjacent grooves 230 in the diagram is the same as the inner diameter of the cylindrical region 220, but these inner diameters may be the same or different. The groove 230 is composed of at least one of a labyrinth groove with a labyrinth seal structure and a screw pump groove that functions as a screw pump, meaning the sealing fluid entering the aforementioned annular gap returns towards the high-pressure side (H). Regarding the labyrinth structure, since it is known technology, its detailed description is omitted, but for example, a labyrinth structure called a straight-through type can be used. That is, by providing at least one groove of appropriate depth, vortices are generated inside the groove, thereby suppressing leakage of the sealing fluid. Furthermore, regarding the screw pump groove, since it is known technology, its detailed description is also omitted, but by providing at least one helical groove or at least one groove inclined relative to the axial direction, dynamic pressure can be generated such that the sealing fluid returns towards the high-pressure side (H) depending on the rotation direction of the rotating shaft 50.

[0047] In addition, the sealing ring 200 also has an annular protrusion 240 that protrudes toward the low-pressure side (L). The front end of the protrusion 240 is configured to contact the surface of the vibration damping ring 300.

[0048] The sealing ring 200, constructed as described above, is configured to remain on the housing 100 in a state where movement in the rotational direction is restricted, and to separate the high-pressure side (H) which is under high pressure during device use from the low-pressure side (L) on the opposite side, thereby performing a sealing function.

[0049] The vibration damping ring 300 is a ring-shaped component made of a metal material, ceramic material, or the like. This vibration damping ring 300 has an annular gap between itself and the rotating shaft 50, and is positioned on the lower pressure side (L) than the sealing ring 200. It is held on the housing 100 in contact with the sealing ring 200. The inner circumferential surface of the vibration damping ring 300 does not perform a sealing function. Therefore, the gap between the sealing ring 200 and the rotating shaft 50 is small, and the annular gap between the vibration damping ring 300 and the rotating shaft 50 does not need to be small. Furthermore, the contact surface between the vibration damping ring 300 and the sealing ring 200 is made flat and has a smooth surface finish, so that when the sealing ring 200 vibrates, frictional resistance is generated between the sealing ring 200 and the vibration damping ring 300, and the fluid to be sealed does not leak from the gap between them. Therefore, to obtain such a surface, it is preferable to use the same material for the vibration damping ring 300 and to perform surface finishing.

[0050] The vibration damping ring 300, constructed as described above, is held in place by an elastic ring 400 made of an elastomer such as rubber. Furthermore, it is configured such that the annular gap between the housing 100 and the vibration damping ring 300 is sealed by the elastic ring 400. Specifically, the elastic ring 400 has a cylindrical portion 410 disposed in the gap between the outer peripheral surface of the vibration damping ring 300 and the inner peripheral surface of the small-diameter portion 120 in the housing 100. Additionally, an annular protrusion 411 is provided on the outer peripheral surface of the cylindrical portion 410, which is disposed when pressed against the inner peripheral surface of the small-diameter portion 120. Furthermore, the elastic ring 400 has an inward flange portion 420 disposed in the gap between the vibration damping ring 300 and the end face of the inward flange portion 121 in the housing 100. The vibration suppression ring 300 is held in place by the elastic ring 400 constructed in this way, so that the vibration suppression ring 300 is held in the housing 100 in both the axial and radial directions.

[0051] The helical spring 500 is made of metal or the like. One end of the helical spring 500 is connected to the inward flange 111 in the housing 100, and the other end is connected to the high-pressure side (H) end face of the annular protrusion 210 in the sealing ring 200. Thus, the sealing ring 200 is pressed against the low-pressure side (L), i.e., against the vibration-damping ring 300. This provides axial positioning of the sealing ring 200. Furthermore, the sealing ring 200 is also positioned radially by the frictional resistance acting between it and the vibration-damping ring 300, combined with the pressure from the helical spring 500, thereby suppressing downward displacement due to its own weight.

[0052] <Advantages of the sealing device involved in this embodiment>

[0053] According to the sealing device 10 of this embodiment, an annular gap is provided between the sealing ring 200 and the outer peripheral surface of the rotating shaft 50. Through the Lomakin effect, an alignment effect is achieved between the rotating shaft 50 and the sealing ring 200, thus keeping the annular gap stable. That is, when the fluid to be sealed flows from the high-pressure side (H) to the low-pressure side (L) through the aforementioned annular gap, a pressure loss occurs. Furthermore, when centrifugal force is generated on the rotating shaft 50 relative to the sealing ring 200, a widening and narrowing portion of the gap is generated circumferentially within the annular gap. In the widening portion, the pressure loss increases and the pressure decreases; in the narrowing portion, the pressure loss decreases and the pressure increases. Therefore, the tilt of the rotating shaft 50 relative to the sealing ring 200 in the direction of eliminating centrifugal force can be adjusted to achieve an alignment effect. Furthermore, even if the rotating shaft 50 does not rotate, such an alignment effect can still be achieved as long as a pressure difference is generated.

[0054] Thus, the sealing device 10 according to this embodiment can utilize the Lomakin effect (alignment effect), thereby preventing the sealing ring 200 from contacting (slipping) with the rotating shaft 50. Furthermore, since the annular gap, set according to the size required to achieve the Lomakin effect, can be made into a very small gap, a sealing function can be achieved.

[0055] Furthermore, at least one of a labyrinth groove and a screw pump groove is provided on the inner circumferential surface of the sealing ring 200. Therefore, combined with the alignment effect described above, the sealing function can be stably performed. Moreover, as described above, stability is maintained by the annular gap, thereby suppressing the influence of the rotational speed of the rotating shaft 50 on the sealing function. Therefore, according to the sealing device 10 of this embodiment, the sealing function can be stably performed even when the rotational speed of the rotating shaft 50 is high.

[0056] Furthermore, the inner circumferential surface of the sealing ring 200 in this embodiment has a cylindrical surface region 220 composed of cylindrical surfaces. Therefore, the Lomage effect (alignment effect) can be performed more reliably and stably. That is, in the sealing ring 200 of this embodiment, the Lomage effect can be performed by the inner circumferential surface as a whole, but the Lomage effect can be performed more reliably by the cylindrical surface region 220, and the groove 230 can more reliably suppress leakage of the fluid of the sealed object.

[0057] Furthermore, in the sealing device 10 of this embodiment, when the rotating shaft 50 vibrates and the sealing ring 200 needs to move radially due to the alignment effect, friction is generated between the sealing ring 200 and the vibration suppression ring 300, thereby suppressing the movement of the sealing ring 200. Thus, the vibration of the rotating shaft itself can be suppressed through the alignment effect of the sealing ring 200. In other words, even if the sealing ring 200 intends to move relative to the rotating shaft 50, this movement is restricted through the alignment effect; conversely, the vibration of the rotating shaft 50 can be suppressed by the alignment effect of the sealing ring 200 on the rotating shaft 50.

[0058] Furthermore, the vibration damping ring 300 is held by the elastic ring 400, so the vibration of each component can also be suppressed through the vibration absorption effect of the elastic ring 400. In addition, since the sealing ring 200 is pressed against the vibration damping ring 300 by the helical spring 500, the formation of a gap between the sealing ring 200 and the vibration damping ring 300 can be suppressed, thereby suppressing the leakage of fluid from the sealed object from the gap.

[0059] Furthermore, to improve the sealing function, the longer the axial length of the inner circumferential surface of the sealing ring 200, the better. In this embodiment, an annular protrusion 210 is provided near the center of the sealing ring 200 in the axial direction, and the helical spring 500 is in contact with the high-pressure side (H) end face of the protrusion 210. Thus, by effectively utilizing the configuration space, the axial length of the inner circumferential surface of the sealing ring 200 is made as long as possible.

[0060] (Example 2)

[0061] Figure 4 and Figure 5 Embodiment 2 of the present invention is shown. Although Embodiment 1 above showed a configuration with a groove on the inner circumferential surface of the sealing ring, this embodiment shows a configuration without such a groove. Furthermore, this embodiment shows a configuration with a retaining member for holding the pressing member. Regarding other configurations and functions, since they are the same as in Embodiment 1, the same reference numerals are used for the same components, and their descriptions are omitted as appropriate.

[0062] Figure 4 This is a partially disconnected cross-sectional view of the sealing device according to Embodiment 2 of the present invention. Viewed from the outer peripheral side of the sealing device, the top side of the figure shows a cross-sectional view after the surface of the sealing device, including the central axis, has been partially cut off. Figure 5 This is a schematic cross-sectional view of the sealing structure according to Embodiment 1 of the present invention. Regarding the sealing device, a cross-sectional view showing the sealing device cut along a surface including the aforementioned central axis is shown. Furthermore, the sealing device has a rotationally symmetric shape, except for a few exceptions.

[0063] <Sealing Structure>

[0064] Especially refer to Figure 5 The sealing structure using the sealing device described in this embodiment will be described. The sealing structure of this embodiment includes a rotating shaft 50; a cover 60 having a shaft hole into which the rotating shaft 50 is inserted; and a sealing device 10A for sealing the annular gap between the rotating shaft 50 and the cover 60. The sealing device 10A is configured to be fixed to the cover 60 and have a gap between it and the rotating shaft 50. By separating the annular gap between the rotating shaft 50 and the cover 60 using the sealing device 10A, leakage of the fluid to be sealed can be suppressed. Furthermore, in Figure 5 In this embodiment, the fluid to be sealed is sealed on the left side relative to the sealing device 10A, and the device operates at high pressure. Hereinafter, the left side of the sealing device 10A will be referred to as the high-pressure side (H), and the opposite side (right side) will be referred to as the low-pressure side (L). In addition, the sealing device 10A according to this embodiment can be appropriately used, for example, as a gas seal (the fluid to be sealed is high-pressure gas) in automotive parts.

[0065] <Sealing device>

[0066] The sealing device 10A according to this embodiment will be described in more detail. The sealing device 10A includes a housing 100; a sealing ring 200A held on the housing 100 and a vibration damping ring 300; an elastic ring 400 for holding the vibration damping ring 300 on the housing 100; and a spring 500A, which serves as a pressing member for pressing the sealing ring 200A toward the vibration damping ring 300. Furthermore, in this embodiment, a retaining member 150 is also included, which is mounted on the housing 100 and holds the spring 500A. Additionally, the sealing ring 200A is made of a material with lower hardness than the vibration damping ring 300.

[0067] The configuration of the housing 100, vibration damping ring 300, and elastic ring 400 is the same as in Embodiment 1 described above, so its description is omitted. Furthermore, the retaining member 150 is mounted on the inner circumferential surface of the large-diameter portion 110 by means of fitting or other methods along the inward flange portion 111 in the housing 100. A cylindrical portion is provided on the inner circumferential surface side of the retaining member 150, through which the spring 500A can be retained (positioned).

[0068] The sealing ring 200A is a ring-shaped component made of carbon material or the like. Similar to Embodiment 1, the sealing ring 200A has an annular protrusion 210 that protrudes radially outward on its outer peripheral surface. At least one location on the outer peripheral surface of the annular protrusion 210 in the circumferential direction has a recess 211 into which a protrusion 112 provided in the housing 100 is pressed. Thus, by pressing the protrusion 112 into the recess 211, the rotational movement of the sealing ring 200 can be restricted.

[0069] The sealing ring 200A is configured with an annular gap between it and the outer peripheral surface of the rotating shaft 50. This annular gap is sized to achieve the Lomakin effect based on the fluid pressure of the sealing fluid entering from the high-pressure side (H) to the low-pressure side (L). Furthermore, in this embodiment, the inner peripheral surface of the sealing ring 200A is formed by a cylindrical surface region 220A, and the groove 230 as in Embodiment 1 is not provided.

[0070] Furthermore, similar to Embodiment 1, the sealing ring 200A also has an annular protrusion 240 protruding toward the low-pressure side (L). The front end of the protrusion 240 is configured to contact the surface of the vibration damping ring 300.

[0071] The sealing ring 200A, constructed as described above, is configured to remain on the housing 100 in a state where movement in the rotational direction is restricted, and to separate the high-pressure side (H) which is under high pressure during device use from the low-pressure side (L) on the opposite side, thereby performing a sealing function.

[0072] Spring 500A is made of metal or the like. One end of spring 500A is held on retaining member 150, and the other end is in contact with the high-pressure side (H) end face of the annular protrusion 210 in sealing ring 200A. Thus, sealing ring 200A is pressed against the low-pressure side (L), i.e., vibration-damping ring 300. This positions sealing ring 200A along its axial direction. Furthermore, sealing ring 200A is also positioned radially by the frictional resistance acting between it and vibration-damping ring 300, combined with the pressure from spring 500A, thereby suppressing downward displacement due to its own weight.

[0073] The sealing device 10A of this embodiment, configured as described above, can achieve the same effect as in Embodiment 1. However, the portion of the inner circumferential surface of the sealing ring 200A in this embodiment without the labyrinth groove and screw pump groove has lower sealing performance compared to Embodiment 1. Nevertheless, since the processing cost of the sealing ring 200A can be controlled only for the portion without grooves, the sealing device 10A of this embodiment is effective when the required sealing performance is not as high. Furthermore, the Lomakin effect is higher than in Embodiment 1.

[0074] Furthermore, since the retaining member 150 is provided in this embodiment, the spring 500A, which serves as the pressing member, can be positioned more accurately. Alternatively, in this embodiment, an annular protrusion 210 can be provided near the center of the sealing ring 200A in the axial direction, and the spring 500A can contact the high-pressure side (H) end face of this protrusion 210. Thus, by effectively utilizing the configuration space, the axial length of the inner circumferential surface of the sealing ring 200A can be made as long as possible.

[0075] (Example 3)

[0076] Figure 6 and Figure 7 Embodiment 3 of the present invention is shown. This embodiment shows a configuration that restricts the movement of the sealing ring relative to the housing in the rotational direction, a configuration different from that of Embodiment 1 described above. Furthermore, this embodiment shows a configuration in which a retaining portion for holding the pressing member is provided on the housing. Regarding other basic configurations and functions, since they are the same as in Embodiment 1, the same reference numerals are used for the same components, and their descriptions are omitted as appropriate.

[0077] Figure 6This is a front view of the sealing device according to Embodiment 3 of the present invention. Figure 7 This is a schematic cross-sectional view of the sealing device according to Embodiment 3 of the present invention, equivalent to... Figure 6 The diagram shows the AA section. Additionally, the sealing device is rotationally symmetrical, except for a portion.

[0078] Regarding the sealing structure of the sealing device 10B involved in this embodiment, it is the same as that in Embodiments 1 and 2 above. The sealing device 10B is configured to be fixed to the cover 60 and have a gap between it and the rotating shaft 50.

[0079] The sealing device 10B according to this embodiment will be described. The sealing device 10B includes: a housing 100B; a sealing ring 200B and a vibration damping ring 300 held in the housing 100B; an elastic ring 400 for holding the vibration damping ring 300 in the housing 100B; and a spring 500B, which serves as a pressing member for pressing the sealing ring 200B toward the vibration damping ring 300. Furthermore, the sealing ring 200B is made of a material with lower hardness than the vibration damping ring 300.

[0080] The configuration of the vibration damping ring 300 and the elastic ring 400 is the same as that in Embodiment 1 above, so the description is omitted.

[0081] Similar to the embodiments described above, the housing 100B is an annular component made of metal or the like. This housing 100B includes a cylindrical large-diameter portion 110 that is fixed to the inner circumferential surface of the shaft hole of the cover 60 by pressing or other means. This embodiment differs from the previous embodiments in that it does not include a small-diameter portion in the housing 100B. Furthermore, in the housing 100B of this embodiment, inward flange portions 111 and 113 are provided at one end and the other end, respectively, of the large-diameter portion 110. In use, the sealing device 10B is positioned within the annular gap between the rotating shaft 50 and the cover 60, such that the inward flange portion 111 becomes the high-pressure side (H) and the inward flange portion 113 becomes the low-pressure side (L).

[0082] Furthermore, in this embodiment, the front end of the inward flange portion 111 of the housing 100B is provided with three bends 111a. These bends 111a serve to retain the spring 500B. That is, this embodiment adopts the structure shown in Embodiment 2, in which the retaining member 150 is integrally formed with the housing 100B. Moreover, in this embodiment, the front end of the inward flange portion 111 of the housing 100B is provided with three recesses 111b for preventing rotation and limiting the movement of the sealing ring 200B in the rotational direction.

[0083] The sealing ring 200B is a ring-shaped component made of carbon material or the like. Similar to Embodiment 1, the sealing ring 200B has an annular protrusion 210B that protrudes radially outward on its outer peripheral surface, and an annular protrusion 240B that protrudes towards the low-pressure side (L) during use. The front end of this protrusion 240B, as in the above embodiment, is configured to contact the vibration-damping ring 300 surface.

[0084] Furthermore, in the sealing ring 200B of this embodiment, three recesses 251B are provided on the opposite side of the protrusion 240B and spaced apart circumferentially. As a result, the protrusions 252B, which are spaced apart between adjacent recesses 251B, react and squeeze into the three recesses 111b at the front end of the inward flange portion 111 provided in the housing 100B, thereby restricting the rotational movement of the sealing ring 200B relative to the housing 100B.

[0085] Furthermore, in this embodiment, the sealing ring 200B is also configured with an annular gap between it and the outer peripheral surface of the rotating shaft 50. This annular gap is determined by the size of the Lomakin effect achieved by the fluid pressure of the sealing fluid entering from the high-pressure side (H) to the low-pressure side (L). Additionally, in this embodiment, the inner peripheral surface of the sealing ring 200B is formed by a cylindrical surface region 220B composed of cylindrical surfaces, and the groove 230 as in Embodiment 1 is not provided.

[0086] The sealing ring 200B, constructed as described above, is configured to remain on the housing 100B in a state where movement in the rotational direction is restricted, and to separate the high-pressure side (H) which is under high pressure during the use of the device from the low-pressure side (L) on the opposite side, thereby performing a sealing function.

[0087] Spring 500B is made of metal or the like. One end of spring 500B is held in the bent portion 111a of the inward flange portion 111 in the housing 100B, and the other end is in contact with the high-pressure side (H) end face of the annular protrusion 210B in the sealing ring 200B. Thus, the sealing ring 200B is pressed against the low-pressure side (L), i.e., the vibration-damping ring 300. This provides axial positioning of the sealing ring 200B. Furthermore, the sealing ring 200B is also positioned radially by the frictional resistance acting between it and the vibration-damping ring 300, combined with the pressure from the spring 500B, thereby suppressing downward displacement due to its own weight.

[0088] The sealing device 10B of this embodiment, configured as described above, can achieve the same effect as in the above embodiment. Furthermore, similar to Embodiment 1 above, this embodiment can also employ a structure with a labyrinth groove and a screw pump groove.

[0089] Label Explanation

[0090] 10, 10A, 10B sealing devices;

[0091] 50 rotating axis;

[0092] 60 masks;

[0093] 100, 100B housing;

[0094] 110 large diameter part;

[0095] 111 Inward flange section;

[0096] 111a Bent section;

[0097] 111b concave part;

[0098] 112 convex part;

[0099] 113 Inward flange section;

[0100] 120mm small diameter section;

[0101] 121 Inward flange section;

[0102] 150 retaining components;

[0103] 200, 200A, 200B sealing rings;

[0104] 210, 210B protrusions;

[0105] 211 concavity;

[0106] Cylindrical regions 220, 220A, and 220B;

[0107] 230 slots;

[0108] 240, 240B protrusions;

[0109] 251B concave part;

[0110] 252B convex part;

[0111] 300 vibration suppression ring;

[0112] 400 elastic ring;

[0113] 410 Cylindrical part;

[0114] 411 Annular protrusion;

[0115] 420 inward flange section;

[0116] 500 helical spring;

[0117] 500A spring.

Claims

1. A sealing device, characterized in that, The sealing device seals the annular gap between the rotating shaft and the cover having a shaft hole for insertion of the rotating shaft. The sealing device has the following features: A housing, which is fixed relative to the shaft hole; A sealing ring is configured to be held on the housing in a state of restricted movement in the rotational direction within the housing, and to separate the high-pressure side, which is under high pressure when the device is in use, from the low-pressure side on the opposite side. A vibration damping ring is positioned closer to the low-pressure side than the sealing ring and is held on the housing in contact with the sealing ring. The pressing component directly presses the sealing ring toward the vibration damping ring; as well as An elastic ring having a cylindrical portion radially located between the outer circumferential surfaces of the housing and the vibration damping ring, and an inwardly facing flange portion axially located between the housing and the vibration damping ring, the elastic ring sealing the annular gap between the housing and the vibration damping ring, and retaining the vibration damping ring relative to the housing. The cylindrical portion has a protrusion on its outer peripheral surface that contacts the inner peripheral surface of the housing. The vibration damping ring contacts the cylindrical portion and the inward flange portion, and the housing contacts the protrusion and the inward flange portion, thereby holding the vibration damping ring within the housing. The sealing ring is configured with an annular gap between it and the outer circumferential surface of the rotating shaft, and the size of the annular gap is set by the fluid pressure of the sealing fluid entering from the high-pressure side to the low-pressure side to achieve the Lomakin effect.

2. The sealing device according to claim 1, characterized in that, The inner circumferential surface of the sealing ring is provided with at least one of a labyrinth groove having a labyrinth sealing structure and a screw pump groove that functions as a screw pump, wherein the screw pump function refers to the function of the sealed fluid entering the annular gap returning towards the high-pressure side.

3. The sealing device according to claim 2, characterized in that, The inner circumferential surface of the sealing ring has a cylindrical surface region composed of cylindrical surfaces, and at least one of the labyrinth groove and the screw pump groove is configured closer to the low-pressure side than the cylindrical surface region.

4. The sealing device according to claim 1, characterized in that, The sealing ring is made of a material with lower hardness compared to the vibration damping ring.

5. The sealing device according to claim 1, characterized in that, The sealing ring is made of carbon material, and the vibration damping ring is made of metal or ceramic material.

6. The sealing device according to any one of claims 1 to 5, characterized in that, It includes a retaining member that is mounted on the housing and retains the pressing member.

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