Shaft seal device

Abstract

This invention provides a shaft sealing device capable of maintaining high lubricity between sliding surfaces. A shaft sealing device includes: a housing having a drive space for receiving a drive unit; a rotating shaft passing through the housing and disposed from the drive space to a space on the side of a sealed fluid; and a sealing assembly disposed between the housing and the rotating shaft, having a pair of sliding members that rotate relative to each other, each pair of sliding members having one of a pair of opposing and sliding surfaces, wherein at least one of the pair of sliding surfaces has a liquid introducing mechanism for introducing liquid from the drive space into the space between the pair of sliding surfaces, wherein the liquid introducing mechanism has a groove formed in at least one of the pair of sliding surfaces, the drive space having a sealing side space divided by the housing and the sealing assembly, and a communication path connecting the sealing side space to provide liquid from the outside to the sealing side space.

Description

[0001] This application is a divisional application of the invention patent application with application number 202280019475.8 (international application number PCT / JP2022 / 009707), application date March 7, 2022, entitled "shaft sealing device". Technical Field

[0002] This invention relates to a shaft sealing device for sealing the shaft between the rotating shaft and the housing of rotating machinery. Background Technology

[0003] As a shaft sealing device used in rotating machinery to prevent leakage of sealed fluid around a rotating shaft, shaft sealing devices using, for example, mechanical seals are known, which consist of a pair of annular sliding members that rotate relative to each other and whose sliding surfaces slide against each other.

[0004] For example, as shown in Patent Document 1, a shaft sealing device for a submersible pump can be described. The shaft sealing device of Patent Document 1 includes: a housing having a closed drive space in which a motor is disposed; a rotating shaft passing through the housing and disposed from the drive space on the leakage side to the water space on the sealed fluid side; and a mechanical seal disposed between the rotating shaft and the housing. By using the motor to drive the rotating shaft to rotate, a pump impeller located at one end of the rotating shaft is driven to rotate, causing water to flow in the water space, and preventing the pair of sliding members constituting the mechanical seal from rotating and sliding relative to each other, thus preventing water from entering the drive space from the water space.

[0005] In a shaft sealing device using a mechanical seal, as described in Patent Document 1, although a liquid film is formed between the sliding surfaces of a pair of sliding parts by water flowing into the space in the water, thereby improving the lubrication between the sliding surfaces during relative rotational sliding, the lubrication performance depends on the type of liquid and it is difficult to achieve stable lubrication.

[0006] Therefore, in shaft sealing devices like the one described above, the following techniques are sometimes employed: a fluid introduction mechanism, such as a spiral groove, is provided to guide fluid from the drive space to between a pair of sliding surfaces. The fluid introduction mechanism causes the fluid in the drive space to move toward the space on the side of the sealed fluid and introduce it between the sliding surfaces, thereby forming a fluid film between the sliding surfaces, ensuring lubrication, and suppressing leakage of the sealed fluid into the drive space.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2016-186297 (page 4) Figure 1 ) Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] When a fluid introduction mechanism as described above is provided between the sliding surfaces of a shaft sealing device like Patent Document 1, although leakage of the sealed fluid into the drive space can be suppressed, since the drive space is a closed space, the fluid in the drive space decreases as the sliding surfaces rotate and slide relative to each other. As a result, it may be impossible to introduce fluid into the sliding surfaces and maintain high lubricity between the sliding surfaces.

[0012] This invention was made in view of such a problem, and its purpose is to provide a shaft seal device that can maintain high lubricity between the sliding surfaces.

[0013] Methods for solving problems

[0014] To address the aforementioned issues, the shaft sealing device of the present invention comprises: a housing having a drive space for accommodating a drive unit; a rotating shaft passing through the housing and disposed from the drive space to a space on the side of the sealed fluid; and a sealing element disposed between the housing and the rotating shaft, the sealing element having a pair of opposing and sliding surfaces, wherein at least one of the pair of sliding surfaces is provided with a fluid introduction mechanism for introducing fluid from the drive space into the space between the pair of sliding surfaces, wherein a communication path communicating with an external space is connected to the drive space.

[0015] Therefore, when the fluid in the drive space is introduced into the space between a pair of sliding surfaces through the fluid introduction mechanism, fluid is replenished from the external space into the drive space through the connecting path. This prevents the fluid in the drive space from decreasing as the sliding surfaces rotate relative to each other, thus maintaining high lubricity between the sliding surfaces.

[0016] Alternatively, the outer casing may be provided with a flow obstruction portion, and the drive space may be divided by the flow obstruction portion into a space on the sealing element side and a space on the drive element side, with the connecting passage connected to the space on the sealing element side.

[0017] Therefore, by replenishing fluid from the external space to the space on the sealing element side through the connecting passage, fluid can be replenished from the external space to the drive space without passing through the flow obstruction, allowing for uninterrupted fluid supply to the fluid introduction mechanism without any obstruction. Furthermore, the pressure difference between the space on the sealing element side and the space on the sealed fluid side can be reduced. Moreover, the sealing element is cooled by the fluid, maintaining good sealing performance.

[0018] Alternatively, the flow obstruction part can be a bearing.

[0019] Therefore, by connecting a connecting passage at a position closer to the sealing element than the bearing, fluid supply to the fluid introduction mechanism can be carried out without interruption.

[0020] Alternatively, the sealing element may be a mechanical seal having a pair of sliding parts that rotate relative to each other.

[0021] Therefore, it is easy to control the amount of fluid introduced into the drive space between the sliding surfaces based on the relative rotation of a pair of sliding components.

[0022] Alternatively, the shaft sealing device can be used for equipment immersed in water, and the communication path has a pipe connected to a communication hole provided in the housing and extending to the external space.

[0023] Therefore, even when the submersible pump is submerged in water, fluid can be supplied from the external space to the drive space through the internal space of the connecting holes and pipes.

[0024] Alternatively, the fluid in the driving space may be gas, and the fluid in the sealed fluid side space may be liquid. The outer shell may have a through hole for the rotating shaft to be inserted through, and a liquid storage tank may be formed at a position closer to the outer diameter of the through hole. The connecting passage may be connected to the driving space at a position higher than the liquid storage tank.

[0025] Therefore, even if liquid leaks from the sealed fluid side into the drive space, the liquid will accumulate in the liquid storage tank, thus maintaining the connection between the drive space and the external space through the communication path configured above the liquid storage tank. Attached Figure Description

[0026] Figure 1 This is a partial cross-sectional view illustrating a shaft sealing device according to an embodiment of the present invention.

[0027] Figure 2 This is an enlarged sectional view of the main part of the shaft sealing device.

[0028] Figure 3 This is a schematic diagram of the sliding surface of the stationary sealing ring viewed from the axial direction.

[0029] Figure 4 (a) is a schematic diagram showing the movement of the fluid in the dynamic pressure generating groove when the rotating sealing ring and the stationary sealing ring rotate relative to each other from the axial direction. Figure 4 (b) is the same schematic cross-sectional view. Detailed Implementation

[0030] Hereinafter, the method of implementing the shaft sealing device of the present invention will be described based on embodiments.

[0031] Example

[0032] Reference Figures 1 to 4 The shaft sealing device of the embodiment will be described. This embodiment illustrates a submersible pump used with the pump body submerged in water, but it can also be applied to other rotating machinery. Additionally, for ease of explanation, grooves and other markings formed on the sliding surface are sometimes indicated in the drawings.

[0033] like Figure 1 As shown, the shaft sealing device 1 is provided for sealing the liquid inflow space W, which is the space on the sealed fluid side, and the motor-side drive space A (hereinafter, sometimes simply referred to as drive space A), which is the space on the leakage side. An impeller 16 is disposed in the liquid inflow space W at the lower end of the rotating shaft 15 of the motor 12, which is the drive unit.

[0034] The shaft sealing device 1 mainly includes: a first housing component 10a, which mainly constitutes the housing of the motor 12; a rotating shaft 15 that passes through the first housing component 10a; and a mechanical seal 30 as a sealing element, which is disposed between the first housing component 10a and the rotating shaft 15.

[0035] The housing 10 of the submersible pump P has a first housing component 10a that divides the drive space A and a second housing component 10b that divides the liquid inflow space W. The first housing component 10a and the second housing component 10b are connected in a sealed manner by fastening the flanges 10c and 10d with bolts and nuts 11.

[0036] The drive space A of the first housing component 10a is an enclosed space, having a lower space A1, which is a space on the sealing element side disposed on the mechanical seal 30 side, and an upper space A2, which is a space on the drive unit side disposed on the motor 12 side. The motor 12 is fixedly installed in the upper space A2 of the first housing component 10a. The motor 12 is controlled by power input from the outside via cable 19 and control signals, etc.

[0037] The first housing component 10a has: a first partition wall 10e that extends horizontally and divides a lower space A1 and an upper space A2; and a second partition wall 10f that extends horizontally and divides the lower space A1 and a liquid inflow space W disposed below it.

[0038] Through holes 10g and 10h are formed in the first partition wall portion 10e and the second partition wall portion 10f, respectively, which allow the rotating shaft 15 extending in the vertical direction to be inserted through.

[0039] The upper part of the through hole 10g in the first partition wall 10e is a large-diameter hole, and the lower part is a small-diameter hole. A stepped portion 10j is formed on the inner diameter side of the first partition wall 10e through the large-diameter hole and the small-diameter hole. A bearing 14, which serves as a flow obstruction and keeps the rotating shaft 15 rotatable, is fixed to the stepped portion 10j. Alternatively, the flow obstruction can be composed of components other than the bearing 14. For example, a sealing device such as an oil seal or a lip seal can be provided as a single unit, and the sealing device and the bearing can be arranged axially.

[0040] In this embodiment, the bearing 14 is a rolling bearing, and the lower space A1 and the upper space A2 are connected by a small gap between the components constituting the bearing 14. That is, the lower space A1 and the upper space A2 are throttled by the bearing 14, i.e., the flow obstruction part, and are divided in a state where fluid movement is difficult.

[0041] An annular liquid storage tank 18 is formed at a position on the second partition wall 10f that is further away from the outer diameter side than the through hole 10h. The inner diameter side of this liquid storage tank 18 is a conical surface that expands from the upper surface of the second partition wall 10f toward the lower outer diameter side. Therefore, even if liquid flowing into the space W enters the lower space A1, the liquid can be guided toward the outer diameter side. In addition, the liquid storage tank 18 is not limited to annular shape, and multiple tanks can be provided circumferentially.

[0042] Furthermore, a through hole 10k is formed in the lower part of the side wall of the first housing component 10a, communicating with the lower space A1, and the through hole 10k is connected to one end of the pipe 13. The other end of the pipe 13 extends to the external space (hereinafter also referred to as the atmospheric space). That is, the through hole 10k and the pipe 13 form a communication path connecting the lower space A1 with the atmospheric space, driving space A to fill with air. In addition, the external space refers to the space different from the water space in which the submersible pump P is immersed.

[0043] In addition, the connecting hole 10k is located above the upper surface of the second partition wall 10f, i.e., above the liquid storage tank 18.

[0044] In addition, a filter 2 is provided at the connecting hole 10k to prevent foreign objects from entering the lower space A1.

[0045] In addition, a moisture-absorbing material 3 is provided on the inner wall of the lower space A1 (more specifically, the upper inner wall) to absorb moisture inside the lower space A1. The moisture-absorbing material 3 can be a material that absorbs moisture from the gas, such as potassium chloride, silicon dioxide, or quicklime.

[0046] Furthermore, a temperature-changing mechanism 4 is installed inside the lower space A1, capable of altering the temperature within the lower space A1. The temperature-changing mechanism 4 can cause surrounding moisture to condense by heating or cooling. The condensed moisture is then removed by the moisture-absorbing material 3.

[0047] The second housing component 10b internally forms a liquid inflow space W and serves as a housing for the impeller 16, which is disposed at the lower end of the rotating shaft 15. The second housing component 10b is provided with an inlet 10m communicating with the underwater space where the submersible pump P is located, and an outlet 10n connected to a pipe (not shown). The impeller 16, through rotational drive, imparts a moving force to the liquid (i.e., water) in the liquid inflow space W, directing it from the inlet 10m toward the outlet 10n, thus functioning as a pump.

[0048] A mechanical seal 30 is provided between the through hole 10h of the first housing component 10a and the rotating shaft 15. The mechanical seal 30 seals the liquid inflow space W and the drive space A along the rotating shaft 15. In other words, the mechanical seal 30 seals the gap between the outer peripheral surface of the rotating shaft 15 and the inner peripheral surface of the through hole 10h of the first housing component 10a.

[0049] Reference Figure 2 The mechanical seal 30 mainly comprises: a rotary sealing ring 31 as a sliding member, having a rotary sliding surface 31s; and a stationary sealing ring 32 as a sliding member, having a stationary sliding surface 32s that slides with the rotary sliding surface 31s.

[0050] In detail, the mechanical seal 30 includes a rotating sealing ring 31, a stationary sealing ring 32, a stationary ring sleeve 33, a bellows 34, a clamping ring 35, a spring 37, a mounting accessory 38, and a collar 39.

[0051] The rotating sealing ring 31 and the stationary sealing ring 32 are typically formed from a combination of SiC (hard material) and SiC (hard material) or a combination of SiC (hard material) and carbon (soft material), but are not limited to these. Any sliding material that can be used as a sliding material for mechanical seals can be applied. Furthermore, SiC can be materials composed of two or more phases with different compositions, such as sintered bodies using boron, aluminum, carbon, etc., as sintering aids. Examples include SiC with dispersed graphite particles, reaction-sintered SiC composed of SiC and Si, SiC-TiC, SiC-TiN, etc. As for carbon, resin-molded carbon and sintered carbon, represented by carbonaceous and graphitic mixtures, can be used. In addition to the above-mentioned sliding materials, metallic materials, resin materials, surface-modified materials (coating materials), composite materials, etc., can also be used.

[0052] The rotating side sliding surface 31s of the rotating sealing ring 31 is formed with a radial width smaller than that of the stationary side sliding surface 32s of the stationary sealing ring 32. Multiple hydrodynamic grooves 40, which serve as a fluid introduction mechanism and will be described later, are formed on the stationary side sliding surface 32s of the stationary sealing ring 32. Figure 3 Furthermore, the specific structure of the dynamic pressure generating groove 40 will be described in detail later.

[0053] The bellows 34 is made of a material capable of elastic deformation, such as rubber. The bellows 34 has: a cylindrical portion 34a, which is tightly and sealingly mounted to the outer peripheral surface of the rotating shaft 15; and an annular portion 34b, which bends outward from the end of the cylindrical portion 34a on the drive space A side. A clamping ring 35 is disposed on the outer peripheral surface of the cylindrical portion 34a, and the cylindrical portion 34a is fastened to the outer peripheral surface of the rotating shaft 15 by the clamping ring 35.

[0054] Furthermore, regarding the annular portion 34b, the outer periphery of the annular portion 34b and the outer periphery of the rotary sealing ring 31 are fixed in a sealed manner by riveting based on the mounting fitting 38.

[0055] Spring 37 is disposed on the outer periphery of bellows 34. The upper end of spring 37 abuts against the lower surface of mounting fitting 38, and the lower end of spring 37 abuts against spring bearing member. The collar 39, disposed below spring bearing member and fixedly mounted on rotating shaft 15, is subjected to reaction force. The spring force of spring 37 exerts a force on rotating sealing ring 31 towards stationary sealing ring 32 via mounting fitting 38.

[0056] The stationary ring sleeve 33 is made of a highly elastic rubber material or synthetic resin. The through hole 10h of the first housing component 10a has a small-diameter hole at the top and a large-diameter hole at the bottom. A stepped portion 10p is formed on the inner diameter side of the second partition wall portion 10f. The stationary ring sleeve 33 is held in a compressed state between the stepped portion 10p of the second partition wall portion 10f and the rotary sealing ring 31. That is, the stationary ring sleeve 33 seals the space between the second partition wall portion 10f and the rotary sealing ring 31.

[0057] Next, based on Figure 3 and Figure 4 The structures of the rotating side sliding surface 31s of the rotating sealing ring 31 and the stationary side sliding surface 32s of the stationary sealing ring 32 will be described. Hereinafter, the rotating side sliding surface 31s and the stationary side sliding surface 32s will be simply referred to as sliding surfaces 31s and 32s.

[0058] like Figure 3 and Figure 4As shown in (a), the rotating sealing ring 31 slides relative to the stationary sealing ring 32 in a counterclockwise direction as indicated by the arrow. On the sliding surface 32s of the stationary sealing ring 32, a plurality of (eight in this embodiment) dynamic pressure generating grooves 40 are evenly distributed circumferentially on the inner diameter side.

[0059] Furthermore, the sliding surface 31s of the rotary sealing ring 31 is larger in the radial direction than the dynamic pressure generating groove 40, and the radial width of the sliding surface 31s is smaller than the radial width of the sliding surface 32s. Additionally, the number of dynamic pressure generating grooves 40 can be freely varied. Moreover, the sliding surface 31s is formed as a flat surface.

[0060] Furthermore, the portion of the sliding surface 32s other than the dynamic pressure generating groove 40 forms a flat land section 41. In detail, the land section 41 has a portion between the circumferentially adjacent dynamic pressure generating grooves 40 and an annular portion disposed on the outer diameter side of each dynamic pressure generating groove 40. These portions are disposed in the same plane as the surface of the sliding surface 32s side of the land section 41 (hereinafter also referred to as the flat surface of the land section 41).

[0061] The inner diameter end of the dynamic pressure generating groove 40, i.e., the relative rotation start end 40A, is connected to the drive space A. From the start end 40A toward the outer diameter side, the dynamic pressure generating groove 40 extends in an arc shape while tilting toward the rotation end side of the rotary sealing ring 31. The outer diameter end of the dynamic pressure generating groove 40, i.e., the relative rotation end 40B, is closed by the wall portion 40b, thus becoming non-connected with the liquid inflow space W. This dynamic pressure generating groove 40 is an arc shape that bulges toward the outer diameter side.

[0062] Specifically, the dynamic pressure generating groove 40 has: a bottom surface 40a, which is flat from the beginning end 40A to the end end 40B and parallel to the flat surface of the land portion 41; a wall portion 40b, which extends vertically from the end edge of the end end 40B of the bottom surface 40a toward the sliding surface 32s; and side wall portions 40c and 40d, which extend vertically from both sides of the bottom surface 40a toward the sliding surface 32s.

[0063] In addition, the angle between the wall portion 40b and the side wall portion 40c is an obtuse angle, and the angle between the wall portion 40b and the side wall portion 40d is an acute angle. The acute angle portion of the side wall portion 40d of the wall portion 40b is located closer to the rotating end side of the rotating sealing ring 31 than the obtuse angle portion of the side wall portion 40c of the wall portion 40b.

[0064] These dynamic pressure generating grooves 40 are configured such that adjacent dynamic pressure generating grooves 40 overlap radially when viewed from the axial direction.

[0065] In addition, such as Figure 4 As shown in (b), the dynamic pressure generating groove 40 starts from the beginning end 40A (refer to...). Figure 3 and Figure 4(a) has a constant depth D to terminal 40B. Additionally, Figure 4 (b) is a schematic cross-sectional view of a 1-hydrodynamic pressure generating groove 40 after being cut along its length.

[0066] Furthermore, in this embodiment, the dynamic pressure generating groove 40 is shown to be formed with a constant depth D, but it is not limited to this. For example, it may be inclined in a way that it becomes shallower from the beginning to the end, or it may be formed with multiple steps in a way that it becomes shallower from the beginning to the end. In addition, the bottom of the dynamic pressure generating groove is not limited to a planar shape, and may also be curved. That is, as long as fluid can be introduced into the sliding surface by rotating the sealing ring, and pressure can be generated in the sliding surface, it is acceptable.

[0067] Next, use Figure 4 The operation of the stationary sealing ring 32 and the rotating sealing ring 31 when they rotate relative to each other will be explained. First, when the submersible pump P is not operating and the rotating sealing ring 31 is not rotating, air in the drive space A flows into the dynamic pressure generating groove 40. In addition, the rotating sealing ring 31 is forced towards the stationary sealing ring 32 by the pressure of the spring 37 and the liquid flowing into the liquid-inflow space W. Therefore, the sliding surfaces 31s and 32s are in contact with each other, and the amount of liquid flowing into the liquid-inflow space W (hereinafter referred to as the sealed fluid) entering between the sliding surfaces 31s and 32s is almost zero.

[0068] When the rotating sealing ring 31 rotates relative to the stationary sealing ring 32, as Figure 4 As indicated by the white arrow, the air in the dynamic pressure generating groove 40 moves in the direction of rotation of the rotating sealing ring 31 due to friction with the sliding surface 31s, and the air in the driving space A is introduced into the dynamic pressure generating groove 40. That is, within the dynamic pressure generating groove 40, the air in the driving space A moves from the beginning end 40A toward the end end 40B.

[0069] The air moving toward the terminal 40B experiences increased pressure at and near the acute angle of the terminal 40B of the dynamic pressure generating groove 40. That is, positive pressure is generated at and near the acute angle.

[0070] The sliding surfaces 31s and 32s are slightly separated by the force F generated by the positive pressure generated at and near the acute angle. As a result, air, primarily from the dynamic pressure generating groove 40, flows into the space between the sliding surfaces 31s and 32s. This air presence between the sliding surfaces 31s and 32s improves lubrication (so-called gas lubrication) and suppresses wear between them. Additionally, the air flowing into the space between the sliding surfaces 31s and 32s can also leak slightly into the liquid inflow space W.

[0071] Furthermore, at this time, due to the slight separation between the sliding surfaces 31s and 32s, the sealed fluid flows into the acute angle of the dynamic pressure generating groove 40 and its vicinity. However, since positive pressure is generated in the acute angle of the dynamic pressure generating groove 40 and its vicinity, the sealed fluid, as the liquid flowing into the space W side, hardly enters the position closer to the inner diameter side, i.e., the drive space A side, than the acute angle and its vicinity.

[0072] return Figure 1 When the rotating sealing ring 31 and the stationary sealing ring 32 rotate relative to each other, although the air in the driving space A is introduced into the dynamic pressure generating groove 40, the amount of air introduced into the dynamic pressure generating groove 40 can be replenished from the atmospheric space through the connecting hole 10k and the pipe 13 that are connected to the lower space A1 of the driving space A.

[0073] Thus, when the rotating sealing ring 31 and the stationary sealing ring 32 rotate relative to each other, and air from the drive space A is introduced between the sliding surfaces 31s and 32s using the dynamic pressure generating groove 40, air is replenished into the drive space A from the external atmospheric space through the connecting hole 10k and the pipe 13. This prevents the air in the drive space A from decreasing drastically due to the relative rotation and sliding of the sliding surfaces 31s and 32s, suppressing poor lubrication between the sliding surfaces 31s and 32s caused by insufficient air, and maintaining high lubricity. Furthermore, since the air in the drive space A moves towards the liquid inflow space W, the sealed fluid in the liquid inflow space W is less likely to leak into the drive space A.

[0074] Furthermore, it can prevent the gas pressure in the drive space A from decreasing due to a reduction in gas, thus avoiding a near-vacuum state.

[0075] Furthermore, the fluid within the drive space A is air, allowing air to flow from the atmospheric space into the drive space A. Therefore, there is no need to install pumps or similar equipment in the external space or connecting passages to replenish air from the atmospheric space into the drive space A, enabling a simpler construction.

[0076] Furthermore, since the fluid in the driving space A is at atmospheric pressure, it is possible to prevent the force generated by the fluid pressure in the driving space A from affecting the sliding pressure between the sliding surfaces 31s and 32s.

[0077] Furthermore, the drive space A is divided by the bearing 14 that guides the rotation of the rotating shaft 15 into a lower space A1 on the mechanical seal 30 side and an upper space A2 on the motor 12 side, and the connecting hole 10k communicates with the lower space A1.

[0078] Therefore, by supplying air from the atmospheric space to the lower space A1 through the connecting hole 10k and the pipe 13, the pressure drop in the lower space A1 can be suppressed, thereby reducing the pressure difference between the lower space A1 and the upper space A2 and suppressing the movement of air between the lower space A1 and the upper space A2. Thus, it is possible to prevent dust or lubricating oil from the bearing 14 from entering the lower space A1 along with the movement of air between the lower space A1 and the upper space A2, thereby preventing it from affecting the mechanical seal 30.

[0079] In addition, the sealing element is a mechanical seal 30 having a rotating sealing ring 31 and a stationary sealing ring 32. The fluid introduction mechanism that introduces air from the drive space A into the sliding surface is a dynamic pressure generating groove 40 provided on the sliding surface 32s of the stationary sealing ring 32. Since the rotating shaft 15 and the housing 10 are not used as sliding surfaces, it is easy to control the amount of air introduced into the drive space A between the sliding surfaces 31s and 32s according to the relative rotation speed of the rotating sealing ring 31 and the stationary sealing ring 32.

[0080] Furthermore, the shaft seal device 1 is used for the submersible pump P, and the pipe 13 extends from the connecting hole 10k to the atmospheric space. Therefore, even when the submersible pump P is immersed in water, air can be supplied from the atmospheric space to the drive space A through the connecting hole 10k and the internal space of the pipe 13. Additionally, the pipe 13 can be either a flexible pipe made of resin or the like, or a non-flexible pipe such as a metal conduit.

[0081] Furthermore, the drive space A is positioned vertically above the liquid inflow space W. The first housing component 10a has a through hole 10h for the vertical insertion of the rotating shaft 15 and a liquid storage tank 18 positioned on the outer diameter side above the through hole 10h. A connecting hole 10k communicates with the lower space A1 of the drive space A at a position above the liquid storage tank 18. Therefore, even if the sealed fluid leaks from the liquid inflow space W into the lower space A1, it will accumulate in the liquid storage tank 18. Thus, the connecting hole 10k positioned above the liquid storage tank 18 will not be blocked by the sealed fluid, maintaining communication between the lower space A1 and the atmosphere.

[0082] In addition, in the embodiment, a second partition wall 10f dividing the lower space A1 and the liquid inflow space W is provided on the first housing member 10a, but it is not limited to this. It may also be provided on the second housing member 10b, or the lower space A1 and the liquid inflow space W may be divided by a component different from the first housing member 10a and the second housing member 10b.

[0083] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the specific structure is not limited to these embodiments, and changes and additions that do not depart from the spirit of the present invention are also included in the present invention.

[0084] For example, in the above embodiment, a motor was exemplified as the driving unit, but it is not limited to this; any device that performs the driving function is acceptable.

[0085] In addition, in the above embodiment, a filter 2 is provided at the connecting hole 10k, but it is not limited to this. A filter can also be provided at the pipe 13. Furthermore, it is not limited to a filter. It can be a cyclone separator or other component that prevents foreign objects from entering the lower space A1.

[0086] In addition, in the above embodiment, a moisture-absorbing material is provided on the inner wall of the lower space A1, but it is not limited to this. The moisture-absorbing material can also be provided in the same location as the filter. Furthermore, if the moisture-absorbing material can be used to prevent foreign objects from entering, the moisture-absorbing material can be provided instead of the filter.

[0087] Furthermore, in the above embodiment, the communication route connecting the drive space A to the external space is illustrated as consisting of the communication hole 10k and the pipe 13, but it is not limited to this. For example, the communication route may also consist of only the communication hole 10k. In this case, the communication hole 10k only needs to be directly connected to the external space without communicating with the space on the sealed fluid side.

[0088] Furthermore, in the above embodiment, the pipe 13 and the cable 19 are provided separately, but this is not a limitation. For example, the cable can pass through the interior of the pipe, forming the pipe and cable integrally. For example, a passageway for the cable to pass through and a connecting path for connecting the drive space with the external space can be provided inside the pipe. Alternatively, the drive space can be connected to the external space through a connecting path provided inside the cable.

[0089] In addition, in the above embodiment, the fluid in the drive space A is illustrated as being at atmospheric pressure, but the fluid in the external space can also be pressurized by a pump or fan and forcibly sent into the drive space A.

[0090] Furthermore, in the above embodiments, a method of connecting the drive space A with the external space is illustrated, but it is not limited to this. For example, instead of connecting the external space, a tank containing a sufficient amount of fluid inside may be connected to the drive space A.

[0091] Furthermore, in the above embodiment, an inner-type mechanical seal 30 is illustrated for sealing fluid that is to be leaked from the outer diameter side of the sliding surface toward the inner diameter side. However, it is not limited to this; an outer-type mechanical seal can also be used to seal fluid that is to be leaked from the inner diameter side of the sliding surface toward the outer diameter side. In this case, it is sufficient that the rotating sealing ring is disposed on the lower space A1 side and the stationary sealing ring is disposed on the liquid inflow space W side.

[0092] Furthermore, in the above embodiment, an example of providing the dynamic pressure generating groove 40 on the stationary sealing ring 32 was described, but the dynamic pressure generating groove can also be provided on the rotating sealing ring 31, or on both the stationary sealing ring 32 and the rotating sealing ring 31.

[0093] Furthermore, the dynamic pressure generating groove 40 in the above embodiment extends in an arc shape from the driving space A side toward the liquid inflow space W, but is not limited to this. For example, it may also extend in a straight line from the driving space A side toward the liquid inflow space W, as long as it has a closed terminal portion for generating dynamic pressure. In addition, the dynamic pressure generating groove may not have acute or obtuse angle portions, or the corners of the dynamic pressure generating groove may be curved when viewed from the axial direction.

[0094] Alternatively, the beginning 40A of the dynamic pressure generating groove 40 may not be open in a manner that connects to the drive space A, and the dynamic pressure generating groove may also be a recess surrounded by a land area. In this case, it is sufficient as long as the recess is positioned close to the drive space A, or the fluid pressure in the drive space A is slightly higher than the fluid pressure in the liquid flowing into the space W.

[0095] In addition, the fluid introduction mechanism is not limited to the dynamic pressure generating groove, but can also be a structure that can only introduce fluid in the drive space A into the sliding surface without generating almost no dynamic pressure.

[0096] In addition, in the above embodiment, the fluid pressure in the drive space A is shown to be lower than the fluid pressure in the liquid inflow space W. The fluid pressure in the drive space A may also be the same as or slightly higher than the fluid pressure in the liquid inflow space W.

[0097] In addition, in the above embodiment, the drive space A is illustrated as being divided into a lower space A1 and an upper space A2 by the bearing 14, but it is not limited to this. The bearing 14 may also be disposed outside the drive space A, and the drive space A is a single space.

[0098] Furthermore, in the above embodiment, the connecting path is illustrated as being connected to the lower space A1, but it can also be connected to the upper space A2. In this case, fluid moves from the lower space A1 to the upper space A2 via the bearing 14.

[0099] Furthermore, in the above embodiments, the fluid in the drive space A is illustrated as compressed air, but it is not limited to this and may also be other gases, liquids, or a mist of liquid and gas mixture.

[0100] In addition, in the above embodiments, the fluid in the space on the sealed fluid side is illustrated as water, but it is not limited to this, and can also be other liquids, gases, or a mist of liquid and gas mixture.

[0101] Furthermore, in the above embodiments, the shaft sealing device 1 for the submersible pump P has been described, but it is not limited thereto. The shaft sealing device can also be used in rotating machinery such as automobiles and general industrial machinery.

[0102] Furthermore, in the above embodiment, the rotation axis 15 is illustrated as extending in the vertical direction, but for example, the rotation axis 15 may also be configured to extend in the horizontal direction. In this case, the lower space A1 and the upper space A2 are arranged horizontally.

[0103] Label Explanation

[0104] 1: Shaft sealing device; 10: Housing; 10a: First housing component (outer shell); 10g, 10h: Through hole; 10k: Connecting hole (connecting path); 12: Motor (drive unit); 13: Pipe (connecting path); 14: Bearing; 15: Rotating shaft; 18: Liquid storage tank; 30: Mechanical seal (sealing element); 31: Rotary sealing ring (sliding component); 31s: Rotating side sliding surface; 32: Stationary sealing ring (sliding component); 32s: Stationary side sliding surface; 40: Dynamic pressure generating groove (fluid introduction mechanism); A: Motor side drive space; A1: Lower space (space on the sealing element side); A2: Upper space (space on the drive unit side); P: Submersible pump (equipment); W: Liquid inflow space (space on the sealed fluid side).

Claims

1. A shaft sealing device, comprising: The outer casing has a drive space for housing the drive unit; A rotating shaft, which passes through the housing and is configured from the drive space to the sealed fluid side space; and A sealing assembly, disposed between the housing and the rotating shaft, has a pair of sliding members that rotate relative to each other. Each sliding member has one of a pair of opposing and sliding surfaces. At least one of the sliding surfaces is provided with a liquid introduction mechanism for introducing liquid from the drive space into the space between the sliding surfaces. in, The liquid introduction mechanism has a groove formed in at least one of the pair of sliding surfaces. The drive space has a sealed side space defined by the housing and the sealing assembly. A connecting passage is provided to the sealed side space to supply the liquid from the outside to the sealed side space.

2. The shaft sealing device according to claim 1, wherein, A flow obstruction portion is provided in the outer casing. The drive space is divided into the sealing side space and the drive side space by the flow obstruction portion.

3. The shaft sealing device according to claim 2, wherein, The flow obstruction part is a bearing.

4. The shaft sealing device according to claim 1, wherein, The shaft sealing device is used in equipment immersed in water. The connecting passage has a pipe that connects to a connecting hole disposed in the housing and extends into the external space.

5. The shaft sealing device according to claim 1, wherein, The fluid in the space on the sealed fluid side is a liquid.

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