Magnetic liquid seal device

Abstract

This invention discloses a magnetic liquid sealing device, comprising: a housing, a shaft, a sealing unit, a bushing, and a connecting member. The housing has a cavity, the shaft rotatably extends through the housing, at least a portion of the shaft is located within the cavity, the sealing unit is disposed within the cavity and extends through the shaft, the bushing is sleeved on the shaft and located between the sealing unit and the shaft, the sealing unit and the bushing are spaced apart along the radial direction of the shaft to form a sealing gap, the sealing gap being suitable for filling with magnetic liquid, the bushing having an installation cavity suitable for filling with magnetic liquid, and a first through hole extending radially through the bushing, one end of the first through hole communicating with the installation cavity and the sealing gap, the connecting member being disposed within the first through hole. The magnetic liquid sealing device of this invention has advantages such as simple structure and the ability to replenish or recover the magnetic liquid within the sealing unit.

Description

Technical Field

[0001] This invention relates to the field of mechanical engineering sealing technology, and more specifically, to a magnetic liquid sealing device. Background Technology

[0002] With the increasing complexity of mechanical equipment, sealing technology plays a crucial role in mechanical engineering. Especially in fields requiring high sealing performance, such as high-temperature, high-pressure, or highly corrosive environments, traditional mechanical seals often fail to effectively meet these challenges. Magnetic fluid sealing, as an emerging sealing technology, is gradually being applied to various high-end mechanical sealing systems due to its advantages such as non-contact operation, wear-free operation, and corrosion resistance.

[0003] In related technologies, magnetic liquid sealing devices are troublesome to replenish and recycle, cumbersome to operate, and have low maintenance efficiency. Summary of the Invention

[0004] This invention is based on the inventor's discoveries and understanding of the following facts and problems: In related technologies, the injection method for magnetic fluid sealing devices mostly relies on syringes. This injection method is difficult to replenish the magnetic fluid in the sealing gap, making effective maintenance impossible. Furthermore, due to the high cost of magnetic fluid, after the magnetic fluid is injected into the sealing gap using traditional methods, it becomes unusable as the sealed component is damaged, making it impossible to recover the magnetic fluid in the sealing gap and resulting in resource waste.

[0005] Furthermore, the liquid injection method typically requires a large space and involves a relatively cumbersome process, making it unsuitable for use in compact structures or under special operating conditions. Additionally, because the injection volume cannot be precisely controlled, excessive magnetic fluid can increase the equipment's starting torque, while insufficient injection volume cannot form an effective sealing ring, affecting the sealing effect and the reliability of equipment operation.

[0006] The present invention aims to at least partially solve one of the technical problems in the related art.

[0007] Therefore, embodiments of the present invention provide a magnetic liquid sealing device that is convenient to replenish and recycle and easy to operate.

[0008] A magnetic liquid sealing device according to an embodiment of the present invention includes: a housing having a chamber; a shaft and a sealing unit, the shaft being rotatably passed through the housing, at least a portion of the shaft being located within the chamber, the sealing unit being disposed within the chamber and passing through the shaft; a bushing and a connecting member, the bushing being sleeved on the shaft and located between the sealing unit and the shaft, the sealing unit and the bushing being spaced apart along the radial direction of the shaft to form a sealing gap, the sealing gap being adapted to be filled with a magnetic liquid, the bushing having a mounting cavity adapted to be filled with the magnetic liquid, the bushing having a through hole extending through the bushing in its radial direction, one end of the through hole communicating with the mounting cavity and the sealing gap. The connecting member is disposed within the through hole. The magnetic liquid sealing device has a first state, a second state, and a third state. In the first state, the connecting member is in the open state, the sealing gap and the mounting cavity are connected through the through hole, and the magnetic liquid in the mounting cavity flows into the sealing gap to replenish the sealing gap with magnetic liquid. In the second state, the connecting member is in the open state, the sealing gap and the mounting cavity are connected through the through hole, and the magnetic liquid in the sealing gap flows into the mounting cavity to recover the magnetic liquid in the sealing gap. In the third state, the connecting member is in the closed state, the sealing gap and the mounting cavity are disconnected to ensure the stability of the magnetic liquid in the sealing gap.

[0009] The magnetic liquid sealing device of this invention includes a bushing and a connecting component, enabling directional replenishment of magnetic liquid from the mounting cavity to the sealing gap. This is suitable for scenarios where the amount of magnetic liquid in the sealing gap decreases due to evaporation or leakage, improving the replenishment efficiency of the magnetic liquid and allowing maintenance without disassembly. Furthermore, the magnetic liquid in the sealing gap is returned to the mounting cavity via a suction through-hole, enabling secondary use and reducing the cost of the magnetic liquid. The sealing gap isolates the magnetic liquid from the mounting cavity, preventing its flow and ensuring stable sealing performance. Simultaneously, the bushing's synchronous rotation with the shaft reduces the risk of dynamic leakage, enhancing the reliability, ease of operation, and engineering application value of the magnetic liquid sealing device.

[0010] In some embodiments, the connecting member includes: a sealing plate disposed within the through hole and having elastic deformation capability, the outer peripheral surface of the sealing plate being in contact with the inner peripheral surface of the through hole and one side of the sealing plate being connected to the through hole; and an elastic member disposed within the through hole and located between the sealing plate and the mounting cavity, the two ends of the elastic member being connected to the inner peripheral surfaces of the sealing plate and the mounting cavity, respectively.

[0011] In some embodiments, in the first state, the magnetic fluid is injected into the mounting cavity, and the magnetic fluid in the mounting cavity squeezes the sealing plate against the elastic force of the elastic member to squeeze the sealing plate. The sealing plate rotates away from the mounting cavity to open the sealing plate so that the magnetic fluid in the mounting cavity flows into the sealing gap. In the second state, the sealing fluid in the mounting cavity is extracted, and a negative pressure is formed in the through hole to drive the sealing plate to rotate towards the side adjacent to the mounting cavity to open the sealing plate so that the magnetic fluid in the sealing gap flows into the mounting cavity.

[0012] In some embodiments, the sealing unit includes: at least two pole shoes, the at least two pole shoes being disposed on the bushing and spaced apart along the axial direction of the bushing, the inner circumferential surface of the pole shoes being spaced apart from the outer circumferential surface of the bushing along the radial direction of the bushing, and a magnetic fluid filling the space between the bushing and the pole shoes; and a permanent magnet, the permanent magnet being sleeved on the bushing and disposed between adjacent pole shoes.

[0013] In some embodiments, the inner circumferential surface of the pole shoe is provided with a plurality of pole teeth, the plurality of pole teeth are spaced apart along the axial direction of the shaft, and each pole tooth and the outer circumferential surface of the bushing are spaced apart along the radial direction of the shaft to form the sealing gap. There are a plurality of through holes and a plurality of connecting members. One end of each of the plurality of through holes is connected to the mounting cavity, and the other end of each of the plurality of through holes is connected to the sealing gap. The plurality of through holes and the plurality of pole teeth are arranged opposite each other at intervals along the radial direction of the shaft, and the plurality of connecting members are arranged correspondingly in the through holes.

[0014] In some embodiments, the outer circumferential surface of the bushing is provided with a plurality of grooves, the plurality of grooves are spaced apart along the axial direction of the bushing, each groove extends circumferentially along the bushing, and the plurality of grooves and the plurality of pole teeth are spaced apart in a one-to-one correspondence along the axial direction of the shaft.

[0015] In some embodiments, the projection of the pole tooth is located within the groove in a projection plane orthogonal to the axis.

[0016] In some embodiments, one end of the mounting cavity has a liquid inlet communicating with the mounting cavity, and a plurality of pole teeth are spaced apart from the bushing to form a plurality of sealing gaps, the size of the plurality of sealing gaps gradually decreasing in the direction away from the liquid inlet.

[0017] In some embodiments, there are multiple through holes, which are spaced apart in multiple rows along the axial direction of the shaft. Each row includes several through holes spaced apart circumferentially along the bushing. There are multiple connecting members, which are correspondingly arranged in the bushing.

[0018] In some embodiments, the magnetic liquid sealing device further includes a seal disposed between the bushing and the shaft. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the magnetic liquid sealing device according to an embodiment of the present invention.

[0020] Figure 2 yes Figure 1 A magnified view of part A in the image.

[0021] Figure 3 This is a schematic diagram of the second state of the magnetic liquid sealing device according to an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of the structure of the bushing of the magnetic liquid sealing device according to an embodiment of the present invention in its first state.

[0023] Figure 5 yes Figure 4 A magnified view of part B in the image.

[0024] Figure 6 This is a schematic diagram of the structure of the bushing of the magnetic liquid sealing device in the second state according to an embodiment of the present invention.

[0025] Figure 7 yes Figure 6 A magnified view of part C.

[0026] Figure 8 This is a schematic diagram of the structure of the bushing of the magnetic liquid sealing device in the third state according to an embodiment of the present invention.

[0027] Figure 9 yes Figure 8 A magnified view of part of D.

[0028] 100. Magnetic liquid sealing device; 1. Housing; 2. Shaft; 3. Sealing unit; 31. Pole shoe; 311. Pole tooth; 32. Permanent magnet; 33. Magnetic liquid; 4. Bushing; 41. Mounting cavity; 42. Through hole; 43. Groove; 44. First protrusion; 45. Second protrusion; 46. Liquid inlet; 5. Connecting element; 51. Sealing plate; 52. Elastic element. Detailed Implementation

[0029] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0030] The magnetic liquid sealing device 100 according to an embodiment of the present invention is described below with reference to the accompanying drawings.

[0031] like Figures 1-9 As shown, the magnetic liquid sealing device 100 according to an embodiment of the present invention includes a housing 1, a shaft 2, a sealing unit 3, a bushing 4, and a connecting member 5.

[0032] The housing 1 has a cavity, and a shaft 2 rotatably passes through the housing 1, with at least a portion of the shaft 2 located within the cavity. A sealing unit 3 is disposed within the cavity and passes through the shaft 2. Specifically, as shown... Figure 1 and Figure 3 As shown, the chamber of the housing 1 is cylindrical and can be installed on external equipment (e.g., a reactor and a reaction vessel). The shaft 2 is a rotating shaft extending in the left and right direction and is rotatably supported in the housing 1 by bearings. The sealing unit 3 is installed in the chamber of the housing 1 and passes through the shaft 2.

[0033] A bushing 4 is fitted onto the shaft 2 and located between the sealing unit 3 and the shaft 2. The sealing unit 3 and the bushing 4 are spaced apart along the radial direction of the shaft 2 to form a sealing gap. The sealing gap is suitable for filling with magnetic liquid 33. The bushing 4 has an installation cavity 41, which is also suitable for filling with magnetic liquid 33. The bushing 4 has a through hole 42 that penetrates the bushing 4 along its radial direction. One end of the through hole 42 communicates with the installation cavity 41 and the sealing gap. A connecting piece 5 is provided in the through hole 42. The bushing 4 is fitted onto the shaft 2 and rotates synchronously with the shaft 2, and is located between the sealing unit 3 and the shaft 2. The sealing unit 3 and the bushing 4 are spaced apart along the inner and outer directions to form a sealing gap. Magnetic liquid 33 can be filled into the sealing gap. The sealing unit 3 can generate a magnetic field, causing the magnetic liquid 33 to be adsorbed between the sealing unit 3 and the bushing 4, thereby effectively preventing external media (such as gas, liquid, etc.) from entering the interior of external equipment and forming a liquid sealing barrier under the action of the magnetic field.

[0034] The bushing 4 has an internal mounting cavity 41 filled with magnetic liquid 33. The through hole 42 extends in the inward and outward directions and its two ends are connected to the mounting cavity 41 and the sealing gap, respectively. The connecting piece 5 is provided in the through hole 42 to control the opening and closing of the mounting cavity 41 and the sealing gap.

[0035] The magnetic liquid sealing device 100 has a first state, a second state, and a third state. In the first state, the connecting member 5 is in the open state, and the sealing gap and the mounting cavity 41 are connected through the through hole 42. The magnetic liquid 33 in the mounting cavity 41 flows into the sealing gap to replenish the sealing gap. In the second state, the connecting member 5 is in the open state, and the sealing gap and the mounting cavity 41 are connected through the through hole 42. The magnetic liquid 33 in the sealing gap flows into the mounting cavity 41 to recover the magnetic liquid 33 in the sealing gap. In the third state, the connecting member 5 is in the closed state, and the sealing gap and the mounting cavity 41 are disconnected to ensure the stability of the magnetic liquid 33 in the sealing gap. Specifically, as shown... Figures 1-9As shown, after the initial installation of the magnetic liquid sealing device 100, it is necessary to fill the sealing gap with magnetic liquid 33. Alternatively, if the magnetic liquid 33 evaporates or leaks during operation, resulting in insufficient filling, the magnetic liquid sealing device 100 is in its first state, with the connecting member 5 in the open state. The sealing gap and the mounting cavity 41 are connected through the through hole 42. Thus, magnetic liquid 33 can flow into the sealing gap through the mounting cavity 41 and the through hole 42 to replenish the magnetic liquid 33 within the sealing gap, ensuring that a sufficient amount of magnetic liquid 33 is always maintained in the sealing gap, thereby maintaining the sealing performance of the sealing gap.

[0036] When the magnetic liquid 33 needs to be recovered, the magnetic liquid sealing device 100 enters the second state. The connecting part 5 remains open, and the sealing gap and the mounting cavity 41 continue to be connected through the through hole 42. By drawing the magnetic liquid 33 outward through the through hole 42, the magnetic liquid 33 in the sealing gap can flow back into the mounting cavity 41 along the through hole 42, thus realizing the recovery of the magnetic liquid 33 in the sealing gap. This not only avoids the waste of the magnetic liquid 33, but also allows for the reallocation of the magnetic liquid 33 when needed, providing flexible support for the subsequent operation of the device.

[0037] When in normal sealing operation, the magnetic liquid sealing device 100 enters the third state, and the connecting member 5 is in the closed state. At this time, the through hole 42 is blocked by the connecting member 5, the communication channel between the sealing gap and the mounting cavity 41 is cut off, and the two are in an independent state, preventing the magnetic liquid 33 between the mounting cavity 41 and the sealing gap from flowing to each other, thereby ensuring the stability of the magnetic liquid 33 in the sealing gap and ensuring the sealing performance of the magnetic liquid sealing device 100.

[0038] The magnetic liquid sealing device 100 of this invention includes a bushing 4 and a connecting member 5. The bushing 4 has an internal mounting cavity 41 for storing magnetic liquid 33. The connecting member 5 controls the opening and closing of the through hole 42. In the first state, the magnetic liquid 33 is replenished from the mounting cavity 41 to the sealing gap, preventing insufficient magnetic liquid 33. This is particularly suitable for scenarios where the amount of magnetic liquid 33 in the sealing gap is reduced due to evaporation or leakage. Compared with related technologies, it facilitates the replenishment of magnetic liquid 33 to the sealing gap, improves the replenishment efficiency, and allows maintenance to be completed without disassembling the device. In the second state, the magnetic liquid 33 in the sealing gap is returned to the mounting cavity 41 by suction through the through hole 42, achieving secondary utilization, reducing the cost of magnetic liquid 33, and solving the resource waste problem of magnetic liquid 33 being discarded when the seal is damaged in related technologies. Finally, in the third state, the through hole 42 is blocked, the sealing gap is isolated from the mounting cavity 41, preventing the magnetic liquid 33 from flowing and ensuring stable sealing performance. At the same time, the design of the bushing 4 rotating synchronously with the shaft 2 reduces the risk of dynamic leakage. Together with the magnetic field effect of the sealing unit 3, a reliable liquid sealing barrier is formed, improving the reliability, ease of operation and engineering application value of the magnetic liquid sealing device 100.

[0039] In some embodiments, the connecting member 5 includes a sealing plate 51 and an elastic member 52.

[0040] The sealing plate 51 is disposed within the through hole 42 and has elastic deformation capability. The outer peripheral surface of the sealing plate 51 is in contact with the inner peripheral surface of the through hole 42, and one side of the sealing plate 51 is connected to the through hole 42. Specifically, as shown... Figure 7 As shown, the sealing plate 51 is a rubber plate with elastic deformation capability. One side of the sealing plate 51 is fixed in the through hole 42 and the outer peripheral surface of the sealing plate 51 is in contact with the inner peripheral surface of the through hole 42, so that the sealing plate 51 can block the through hole 42 and effectively prevent the leakage of magnetic liquid 33 in the non-connected state.

[0041] The elastic element 52 is disposed within the through hole 42 and located between the sealing plate 51 and the mounting cavity 41. Both ends of the elastic element 52 are connected to the inner circumferential surfaces of the sealing plate 51 and the mounting cavity 41, respectively. Specifically, as shown... Figure 7 As shown, the elastic element 52 is a spring. The elastic element 52 is disposed in the through hole 42 and its two ends are connected to the inner circumferential surfaces of the sealing plate 51 and the mounting cavity 41, respectively.

[0042] In some embodiments, in a first state, magnetic fluid 33 is injected into the mounting cavity 41. The magnetic fluid 33 in the mounting cavity 41 compresses the sealing plate 51 against the elastic force of the elastic member 52, causing the sealing plate 51 to rotate away from the mounting cavity 41 to open the sealing plate 51, so that the magnetic fluid 33 in the mounting cavity 41 flows into the sealing gap. Specifically, as Figure 4 and Figure 5As shown, in the first state, the magnetic fluid 33 is injected into the mounting cavity 41, and the magnetic fluid 33 accumulates rapidly in the mounting cavity 41, causing its internal pressure to rise sharply. As the pressure continues to increase, the magnetic fluid 33 exerts a squeezing effect on the sealing plate 51 located in the through hole 42. Under the squeezing of the magnetic fluid 33, the sealing plate 51 overcomes the elastic force generated by the elastic element 52, and the sealing plate 51 begins to deform outward. When the sealing plate 51 deforms to a certain extent, the sealing plate 51 separates from the through hole 42, causing the through hole 42 to open. The magnetic fluid 33 in the mounting cavity 41 can then flow into the sealing gap along the through hole 42, thereby realizing the directional flow of the magnetic fluid 33 between the mounting cavity 41 and the sealing gap.

[0043] In some embodiments, in the second state, the sealing liquid in the mounting cavity 41 is extracted, and a negative pressure is formed in the through hole 42 to drive the sealing plate 51 to rotate toward the side adjacent to the mounting cavity 41, thereby opening the sealing plate 51 so that the magnetic liquid 33 in the sealing gap flows into the mounting cavity 41. Specifically, as Figure 6 and Figure 7 As shown, in the second state, the magnetic fluid 33 is extracted from the mounting cavity 41. As the sealing fluid is gradually extracted from the mounting cavity 41, the pressure in the mounting cavity 41 and the through hole 42 decreases accordingly to form a negative pressure, causing the sealing plate 51 to deform inward. When the sealing plate 51 deforms to a certain extent, the sealing plate 51 separates from the through hole 42, opening the through hole 42 and providing a channel for the magnetic fluid 33 in the sealing gap to flow into the mounting cavity 41. Since the pressure in the sealing gap does not change significantly, a pressure difference is created with the low-pressure environment formed in the mounting cavity 41. Driven by this pressure difference, the magnetic fluid 33 in the sealing gap flows into the mounting cavity 41, completing the transfer process of the magnetic fluid 33 in the second state and realizing the recovery of the magnetic fluid 33.

[0044] In some embodiments, such as Figures 1-3 As shown, the sealing unit 3 includes at least two pole shoes 31 and permanent magnets 32.

[0045] At least two pole shoes 31 are mounted on the bushing 4 and spaced apart along the axial direction of the bushing 4. The inner circumferential surface of the pole shoes 31 and the outer circumferential surface of the bushing 4 are spaced apart along the radial direction of the bushing 4. Magnetic fluid 33 is filled between the bushing 4 and the pole shoes 31. A permanent magnet 32 ​​is mounted on the bushing 4 and positioned between adjacent pole shoes 31. Thus, the magnet, pole shoes 31, and bushing 4 form a closed magnetic circuit. The permanent magnet 32 ​​generates a non-uniform magnetic field with alternating strong and weak magnetic fields between the pole shoes 31 and the bushing 4, attracting the magnetic fluid 33 between the pole teeth 311 and the bushing 4. This allows the magnetic fluid 33 to fill the gap, generating pressure resistance and achieving a seal.

[0046] In some embodiments, the inner circumferential surface of the pole shoe 31 is provided with a plurality of pole teeth 311, which are spaced apart along the axial direction of the shaft 2. Each pole tooth 311 and the outer circumferential surface of the bushing 4 are spaced apart along the radial direction of the shaft 2 to form a sealing gap. There are multiple through holes 42 and multiple connecting members 5. One end of each through hole 42 is connected to the mounting cavity 41, and the other end of each through hole 42 is connected to the sealing gap. The multiple through holes 42 and the multiple pole teeth 311 are arranged opposite each other at intervals along the radial direction of the shaft 2. The multiple connecting members 5 are correspondingly arranged in the through holes 42. Specifically, as shown in Figure 2 As shown, each pole piece 31 is provided with multiple pole teeth 311, which are spaced apart on the inner circumferential surface of the pole piece 31 in the left-right direction. Each pole tooth 311 is spaced apart in the circumferential direction of the pole piece 311. Each pole tooth 311 and the bushing 4 are spaced apart in the inward and outward directions to form a sealing gap. Magnetic fluid 33 is filled between the pole tooth 311 and the bushing 4. There are multiple through holes 42 and multiple connecting parts 5. The number of through holes 42, the number of connecting parts 5 and the number of pole teeth 311 are all equal. One through hole 42 and one pole tooth 311 are arranged opposite each other in the inward and outward directions. When it is necessary to replenish the pole tooth 311 with magnetic fluid 33, the magnetic fluid 33 in the mounting cavity 41 can flow into the sealing gap between the pole tooth 311 and the bushing 4 through the corresponding through hole 42. When the magnetic fluid 33 in the pole tooth 311 needs to flow back to the mounting cavity 41, it can also flow back through the through hole 42, realizing the bidirectional flow of magnetic fluid 33. Each through hole 42 is provided with a connecting member 5. When the connecting member 5 opens the through hole 42, the magnetic liquid 33 can flow freely between the mounting cavity 41 and the pole teeth 311. When the connecting member 5 closes the through hole 42, the fluid channel between the two is cut off, preventing the flow of the magnetic liquid 33. This allows the magnetic liquid sealing device 100 to flexibly adjust the distribution of the magnetic liquid 33 according to different working conditions and sealing requirements, thereby improving the sealing performance and adaptability of the device.

[0047] In some embodiments, the outer circumferential surface of the bushing 4 is provided with a plurality of grooves 43, the plurality of grooves 43 being spaced apart along the axial direction of the bushing 4, each groove 43 extending circumferentially along the bushing 4, and the plurality of grooves 43 and the plurality of pole teeth 311 being spaced apart in a one-to-one correspondence along the axial direction of the shaft 2. Specifically, as Figure 2 As shown, the outer circumferential surface of the bushing 4 is provided with a plurality of grooves 43, the number of grooves 43 being equal to the number of pole teeth 311. The grooves 43 are spaced apart in the left-right direction and extend along the circumference of the bushing 4. The grooves 43 and the pole teeth 311 are spaced apart in the inward-outward direction to form a sealing gap, thereby allowing the magnetic liquid 33 to be adsorbed between the grooves 43 and the pole teeth 311, reducing the cost of the magnetic liquid sealing device 100. The through hole 42 communicates with the grooves 43, allowing the magnetic liquid 33 in the mounting cavity 41 to flow into the grooves 43, or the magnetic liquid 33 in the grooves 43 to flow into the mounting cavity 41.

[0048] In some embodiments, such as Figure 2 As shown, the magnetic liquid sealing device 100 also includes a plurality of first protrusions 44 and a plurality of second protrusions 45. The plurality of first protrusions 44 and the plurality of second protrusions 45 are alternately arranged on the outer peripheral surface of the bushing 4 in the left-right direction. The first protrusions 44 and the second protrusions 45 extend in the circumferential direction of the bushing 4. A first protrusion 44 and a second protrusion 45 and the bushing 4 define a groove 43. The number of grooves 43 is equal to the number of pole teeth 311. Each groove 43 and each pole tooth 311 are spaced apart in the inward and outward directions to define a sealing gap. Thus, the grooves 43 are arranged more reasonably.

[0049] In some embodiments, the projection of the pole tooth 311 is located within the groove 43 in a projection plane orthogonal to axis 2. Specifically, as shown... Figure 2 As shown, the dimension of the pole tooth 311 in the left-right direction is smaller than that of the groove 43 in the left-right direction. The groove 43 provides sufficient space for the magnetic liquid 33, so that the magnetic liquid 33 can exist stably in the groove 43. The size difference between the pole tooth 311 and the groove 43 makes the distribution of the magnetic liquid 33 at the sealing interface more reasonable, which can more effectively prevent the leakage of external media (such as gas or liquid) and improve the reliability of the seal.

[0050] In some embodiments, one end of the mounting cavity 41 has a liquid inlet 46 communicating with the mounting cavity 41, and a plurality of pole teeth 311 are spaced apart from the bushing 4 to form a plurality of sealing gaps, the size of the plurality of sealing gaps gradually decreasing in the direction away from the liquid inlet 46. Specifically, the right end of the bushing 4 is provided with a liquid inlet 46 that communicates with the mounting cavity 41. The height of the multiple pole teeth 311 gradually increases from right to left, causing the dimensions of the multiple sealing gaps to gradually decrease from right to left in the internal and external directions. The right sealing gap is larger, resulting in low flow resistance of the magnetic liquid 33, allowing for rapid filling. Although the magnetic field strength is lower, it is sufficient to attract the magnetic liquid 33 and maintain its stability, preventing premature loss. The left sealing gap is smaller, resulting in high flow resistance of the magnetic liquid 33, but the magnetic field strength is higher, leading to a stronger attraction for the magnetic liquid 33. This compensates for the flow resistance, ensuring that the magnetic liquid 33 gradually fills to the depth of the gap. Therefore, as injection proceeds, the magnetic liquid 33 gradually moves to the left under the action of the magnetic field gradient. However, the right gap, due to its larger size, can still continuously absorb the magnetic liquid 33; the left gap, due to its high magnetic field strength, can quickly stabilize the filled magnetic liquid 33. Ultimately, the filling speed of the magnetic liquid 33 in the two gaps tends to be consistent, achieving synchronous injection and avoiding the injection of excessive magnetic liquid 33.

[0051] In some embodiments, there are multiple through holes 42, which are arranged in multiple rows along the axial direction of the shaft 2. Each row includes several through holes 42 arranged circumferentially along the bushing 4. There are multiple connecting members 5, which are arranged one-to-one in the bushing 4. Specifically, the through holes 42 are arranged in multiple rows along the left-right direction. Each row includes through holes 42 arranged circumferentially along the bushing 4. The number of rows of through holes 42 is equal to the number of grooves 43. Each groove 43 is provided with one row of through holes 42. The number of connecting members is equal to the number of through holes 42. Each through hole 42 is provided with a connecting member 5. Thus, each groove 43 can be simultaneously injected with magnetic liquid 33 through several through holes 42, or the magnetic liquid 33 in the groove 43 can be discharged from the groove 43 through several through holes 42.

[0052] In some embodiments, the magnetic liquid sealing device 100 further includes a sealing element (not shown in the figure), which is disposed between the bushing 4 and the shaft 2. Specifically, the inner circumferential surface of the bushing 4 is provided with an annular groove, the outer ring of the sealing element is installed in the annular groove, and the inner ring of the sealing element is in contact with the outer circumferential surface of the shaft 2, thereby ensuring the sealing performance of the magnetic liquid sealing device 100.

[0053] The structure and operation of the magnetic liquid sealing device 100 according to an embodiment of the present invention are described in detail below: The housing 1 has a cavity. A shaft 2 passes through the cavity and is rotatable relative to the housing 1, with both ends of the shaft 2 extending from opposite sides of the cavity. A bushing 4 is fitted onto the shaft 2 and rotates with it. A pole shoe 31 is fitted onto the bushing 4 and located within the cavity. The pole shoe 31 is connected to the housing 1. The inner circumferential surface of the pole shoe 31 has multiple pole teeth 311 spaced apart axially from the bushing 4. Grooves are formed between adjacent pole teeth 311. The pole teeth 311 at different positions have different tooth heights; the pole teeth 311 closer to the inner sealing side have larger tooth heights. A sealing gap is formed between the pole teeth 311 and the outer circumferential surface of the bushing 4. The pole teeth 311 are magnetic, and a magnetic liquid 33 is adsorbed within the sealing gap. The magnetic liquid 33 is axially confined between the first protrusion 44 and the second protrusion 45, and is adsorbed onto the tooth end face of the pole teeth 311, contacting the outer circumferential surface of the bushing 4 to form an "O" ring, thus achieving a sealing function.

[0054] The bushing 4 includes a mounting cavity 41 for storing magnetic liquid 33, an injection port, first protrusions 44 and second protrusions 45 (equal in number to the O-rings), a through hole 42, a sealing plate 51, and an elastic element 52. The bushing 4 has a mounting cavity 41 for storing magnetic liquid 33. An injection port is located on the right end face of the bushing 4, communicating with the mounting cavity 41. Magnetic liquid 33 can be injected into the mounting cavity 41 through the injection port, and the mounting cavity 41 can be pressurized through the injection port. The outer circumferential surface of the bushing 4 has a number of first protrusions 44 and second protrusions 45 (equal in number to the O-rings). The first protrusions 44 and second protrusions 45 are located on both sides of the O-rings, restricting the axial movement of the magnetic liquid 33. The outer circumferential surface of the bushing 4 also has a number of... The sleeve 4 has a through hole 42, which is radially opposite to the pole teeth 311. Magnetic liquid 33 is injected through the through hole 42 into the sealing gap between the pole teeth 311 and the bushing 4. A sealing plate 51 is provided on the upper side of the through hole 42 of the bushing 4. The sealing plate 51 seals the through hole 42, ensuring that the magnetic liquid 33 is stably stored in the mounting cavity 41 of the bushing 4 without leakage, and preventing backflow of the injected magnetic liquid 33. An elastic element 52 is provided in the mounting cavity 41 of the bushing 4. One end of the elastic element 52 is connected to the inner side of the sealing plate 51, and the other end is fixed to the bottom of the mounting cavity 41 of the bushing 4, where the magnetic liquid 33 is stored. When the magnetic liquid 33 is injected through the injection port and fills the mounting cavity 41, the elastic element 52 is in a stretched state, tightly fitting the sealing plate 51 and the through hole 42 of the bushing 4, ensuring that the magnetic liquid 33 does not leak. During the initial injection, to ensure a precise amount of magnetic liquid 33 is injected into the sealing gap, the injection port is pressurized to a predetermined pressure. Once the predetermined pressure is reached, the internal pressure of the chamber exceeds the tensile force of the elastic element 52 with the maximum elastic coefficient, causing the sealing plate 51 of the bushing 4 to open. Since the tooth heights of different pole teeth 311 are different, the amount of magnetic liquid 33 required for their sealing gaps is also different. The larger the tooth height, the less magnetic liquid 33 is required. By adjusting the injection pressure, the magnetic liquid 33 for different sealing gaps is injected simultaneously. The magnetic liquid 33 is injected through the through hole 42 into the sealing gap between the pole teeth 311 of the pole shoe 31 and the bushing 4 to form a sealing ring. After the predetermined amount of magnetic liquid 33 has been injected, the pressurization is stopped, and the sealing plate 51 is pulled back under the tension of the elastic element 52, sealing the through hole 42 of the bushing 4 and ensuring that the magnetic liquid 33 does not flow back or leak. The first protrusion 44 and the second protrusion 45 restrict the axial movement of the magnetic fluid 33, keeping it stably positioned within the sealing gap between the pole teeth 311 and the bushing 4. When the sealing device is operating normally, the elastic element 52 ensures that the sealing plate 51 is tightly fitted against the through hole 42 of the bushing 4 under the influence of centrifugal force, gravity, etc. By controlling the pressure at the injection port and the preload of the elastic element 52, the volume of the magnetic fluid 33 added to the sealing gap can be controlled.

[0055] When the sealing device is in normal operation, the magnetic liquid 33 in the sealing gap will decrease in volume due to factors such as evaporation, especially on the side closer to the external medium where the evaporation is more obvious. In addition, under certain special working conditions, some O-rings on the side closer to the external medium may be broken, while others remain intact. During maintenance, the injection port is pressurized, and by adjusting the injection pressure, the sealing plate 51 under the sealing gap where the O-rings are broken is opened. The tension of the elastic element 52 controls the opening degree of the sealing plate 51, and the replenished magnetic liquid 33 flows into the sealing gap through the through hole 42. This allows for automatic replenishment of magnetic liquid 33 without disassembling or opening the sealing device, reducing maintenance costs and downtime, and improving sealing effect and equipment safety.

[0056] When the sealing device is damaged or reaches the end of its service life, air is pumped out of the mounting cavity 41 through the injection port, creating a negative pressure inside the cavity. This compresses the elastic element 52, driving the sealing plate 5184 to open inwards into the mounting cavity 41. At this time, the magnetic fluid 33 in the sealing gap flows back into the mounting cavity 41 under the pressure difference, while the original magnetic fluid 33 in the mounting cavity 41 is discharged through the injection port. This method achieves effective recovery and reuse of the magnetic fluid 33, reducing maintenance costs and improving resource utilization efficiency.

[0057] The magnetic liquid sealing device 100 of this invention can achieve quantitative injection of magnetic liquid 33 into the sealing gap, effectively solving the problems of over- or under-injection and improving the reliability and service life of the sealing device. Through the injection structure on the bushing 4, the magnetic liquid 33 can be precisely replenished without disassembling the sealing device, saving maintenance costs and time, and improving the sealing effect and equipment operation safety. Simultaneously, when the sealing device is damaged or reaches its service life, negative pressure can be created by evacuating air through the injection port, causing the magnetic liquid 33 in the sealing gap to flow back into the chamber and be discharged, thereby completing the recovery and reuse of the magnetic liquid 33, further improving resource utilization efficiency and system maintenance convenience.

[0058] In related technologies, replenishing the magnetic liquid 33 typically requires disassembling and reassembling external devices and using a syringe for replenishment. Furthermore, syringe injection is not feasible in compact or confined spaces, making the injection process cumbersome and maintenance complex. This invention, by integrating an injection channel into the bushing 4, simplifies the injection operation and enables rapid maintenance, thereby reducing the overall maintenance difficulty and cost of the equipment.

[0059] In related technologies, the devices cannot achieve secondary utilization of the magnetic fluid 33 in the sealing gap. This invention utilizes an injection channel integrated on the bushing 4, adjusting the balance between the preload of the elastic element 52 and the mounting cavity 41 through the injection port, thereby changing the opening degree of the sealing plate 51. This allows the magnetic fluid 33 to flow back from the sealing gap to the mounting cavity 41, achieving a recycling effect. This structure not only improves the utilization efficiency of the magnetic fluid 33 but also reduces operating costs, showing promising prospects for engineering applications.

[0060] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0062] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0063] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0064] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0065] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A magnetic liquid sealing device, characterized in that, include: A housing having a chamber; A shaft and a sealing unit, wherein the shaft rotatably passes through the housing, at least a portion of the shaft is located within the cavity, and the sealing unit is disposed within the cavity and passes through the shaft; A bushing and a connecting member are provided. The bushing is fitted onto the shaft and located between the sealing unit and the shaft. The sealing unit and the bushing are spaced apart along the radial direction of the shaft to form a sealing gap. The sealing gap is suitable for filling with a magnetic fluid. The bushing has a mounting cavity suitable for filling with the magnetic fluid. The bushing has a through hole extending radially through it. One end of the through hole communicates with the mounting cavity and the sealing gap. The connecting member is disposed within the through hole. The magnetic liquid sealing device has a first state, a second state, and a third state. In the first state, the connecting member is in the open state, the sealing gap and the mounting cavity are connected through the through hole, and the magnetic liquid in the mounting cavity flows into the sealing gap to replenish the sealing gap with magnetic liquid. In the second state, the connecting member is in the open state, the sealing gap and the mounting cavity are connected through the through hole, and the magnetic liquid in the sealing gap flows into the mounting cavity to recover the magnetic liquid in the sealing gap. In the third state, the connecting member is in the closed state, the sealing gap and the mounting cavity are disconnected to ensure the stability of the magnetic liquid in the sealing gap.

2. The magnetic liquid sealing device according to claim 1, characterized in that, The connecting element includes: A sealing plate is disposed within the through hole and has elastic deformation capability. The outer peripheral surface of the sealing plate is in contact with the inner peripheral surface of the through hole, and one side of the sealing plate is connected to the through hole. An elastic element is disposed within the through hole and located between the sealing plate and the mounting cavity, with its two ends connected to the inner circumferential surfaces of the sealing plate and the mounting cavity, respectively.

3. The magnetic liquid sealing device according to claim 2, characterized in that, In the first state, the magnetic fluid is injected into the mounting cavity. The magnetic fluid in the mounting cavity compresses the sealing plate, overcoming the elastic force of the elastic element, thus squeezing the sealing plate. The sealing plate rotates away from the mounting cavity to open it, allowing the magnetic fluid in the mounting cavity to flow into the sealing gap. In the second state, the sealing liquid in the mounting cavity is extracted, and a negative pressure is formed in the through hole to drive the sealing plate to rotate toward the side adjacent to the mounting cavity so that the sealing plate opens, allowing the magnetic liquid in the sealing gap to flow into the mounting cavity.

4. The magnetic liquid sealing device according to claim 1, characterized in that, The sealing unit includes: At least two pole shoes are provided on the bushing and spaced apart along the axial direction of the bushing. The inner circumferential surface of the pole shoes and the outer circumferential surface of the bushing are spaced apart along the radial direction of the bushing. Magnetic fluid is filled between the bushing and the pole shoes. A permanent magnet is sleeved on the bushing and disposed between adjacent pole shoes.

5. The magnetic liquid sealing device according to claim 4, characterized in that, The inner circumferential surface of the pole shoe is provided with a plurality of pole teeth, which are spaced apart along the axial direction of the shaft. Each pole tooth is radially spaced from the outer circumferential surface of the bushing to form the sealing gap. There are multiple through holes and multiple connecting elements. One end of each through hole is connected to the mounting cavity, and the other end of each through hole is connected to the sealing gap. The multiple through holes and multiple pole teeth are arranged radially opposite to each other along the shaft, and the multiple connecting elements are arranged correspondingly in the through holes.

6. The magnetic liquid sealing device according to claim 5, characterized in that, The outer circumferential surface of the bushing is provided with a plurality of grooves, the plurality of grooves are spaced apart along the axial direction of the bushing, each groove extends circumferentially along the bushing, and the plurality of grooves and the plurality of pole teeth are spaced apart in a one-to-one correspondence along the axial direction of the shaft.

7. The magnetic liquid sealing device according to claim 6, characterized in that, In a projection plane orthogonal to the axis, the projection of the pole tooth is located within the groove.

8. The magnetic liquid sealing device according to claim 5, characterized in that, One end of the mounting cavity has a liquid inlet communicating with the mounting cavity, and the multiple pole teeth are spaced apart from the bushing to form multiple sealing gaps, the size of the multiple sealing gaps gradually decreasing in the direction away from the liquid inlet.

9. The magnetic liquid sealing device according to claim 1, characterized in that, There are multiple through holes, which are arranged in multiple rows along the axial direction of the shaft. Each row includes several through holes arranged circumferentially along the bushing. There are multiple connecting members, which are arranged one-to-one in the bushing.

10. The magnetic liquid sealing device according to claim 1, characterized in that, It also includes a seal disposed between the bushing and the shaft.

Images