Self-replenishing magnetic liquid seal

Abstract

The self-supplemental magnetic liquid sealing device comprises a shell, a rotating shaft and at least one pole shoe. The rotating shaft is internally provided with at least one supplement groove for accommodating standby magnetic liquid. The rotating shaft is provided with an opening in communication with the supplement groove on the peripheral surface. The magnetic property of the multiple pole teeth of the pole shoe increases in a stepped manner in the direction away from the supplement groove. When the rotating shaft rotates, the magnetic liquid in the supplement groove flows out from the opening under the action of centrifugal force and is supplemented into the sealing gap of the multiple pole teeth under the attraction of the pole teeth. The device uses the magnetic field strength gradient to make the magnetic liquid fill the sealing gap. The magnetic liquid can be automatically supplemented or replaced without disassembling or opening the sealing device, thereby reducing the maintenance cost and downtime, effectively solving the problem of evaporation of the magnetic liquid, and improving the sealing reliability and service life of the magnetic liquid sealing device.

Description

Technical Field

[0001] This invention belongs to the field of mechanical engineering sealing technology, and in particular relates to a self-replenishing magnetic liquid sealing device. Background Technology

[0002] A magnetic liquid sealing device is a device that utilizes the properties of magnetic liquids to achieve a dynamic seal between a rotating shaft and a sealed container. Magnetic liquid is a colloidal liquid composed of nanoscale magnetic solid particles, surfactants, and a carrier liquid, capable of forming a liquid "O"-ring seal under the influence of a magnetic field. Magnetic liquid sealing devices offer advantages such as zero leakage, high vacuum, long lifespan, low torque loss, pressure differential resistance, high temperature resistance, and corrosion resistance, and are widely used in many fields.

[0003] However, the magnetic liquid sealing devices in related technologies suffer from the problem of magnetic liquid evaporation. Because the carrier liquid of the magnetic liquid has a certain degree of volatility, the amount of magnetic liquid decreases over time, affecting sealing performance and service life. This evaporation is particularly severe under extreme conditions such as high temperature, high pressure, and high speed, requiring regular replenishment or replacement of the magnetic liquid, increasing maintenance costs and downtime. Furthermore, due to the complex structure and strong sealing properties of the magnetic liquid sealing device, replenishing or replacing the magnetic liquid requires disassembling or opening the sealing device, exposing the rotating shaft and sealing container, which may cause leakage or contamination of the sealing medium, affecting the sealing effect and equipment safety. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a self-replenishing magnetic liquid sealing device, which improves the sealing performance and service life of the magnetic liquid sealing device.

[0005] The self-replenishing magnetic liquid sealing device of this invention includes: a housing; a rotating shaft that passes through the housing and is rotatable relative to the housing, the rotating shaft having at least one replenishment groove for accommodating spare magnetic liquid, and an opening communicating with the replenishment groove on the circumferential surface of the rotating shaft; at least one pole shoe that is fitted onto the rotating shaft and located within the cavity of the housing, the pole shoe being connected to the housing, and the inner circumferential surface of the pole shoe having a plurality of pole teeth spaced apart along the axial direction of the rotating shaft, with a tooth groove formed between adjacent pole teeth, and a sealing gap formed between the pole teeth and the outer circumferential surface of the rotating shaft, the pole teeth being magnetic and magnetic liquid being adsorbed within the sealing gap; wherein, the magnetism of the plurality of pole teeth of the pole shoe increases in a stepped manner away from the replenishment groove, and when the rotating shaft rotates, the magnetic liquid in the replenishment groove flows out from the opening under the action of centrifugal force and replenishes the sealing gap of the plurality of pole teeth under the attraction of the pole teeth.

[0006] The self-replenishing magnetic liquid sealing device of this invention can automatically replenish the magnetic liquid in the sealing gap, effectively solving the problem of magnetic liquid evaporation and improving the sealing reliability and service life of the magnetic liquid sealing device. This device utilizes a magnetic field strength gradient to fill the sealing gap with magnetic liquid, reducing the number of replenishment tanks required, lowering manufacturing difficulty, and improving device reliability. The device can automatically replenish the magnetic liquid in the sealing gap without the need for external sensors, further enhancing reliability. Designing the magnetic liquid replenishment tank on the rotating shaft saves axial installation space and allows for automatic replenishment or replacement of the magnetic liquid without disassembling or opening the sealing device, reducing maintenance costs and downtime, and improving sealing effect and equipment safety.

[0007] In some embodiments, the width of the sealing gap between the plurality of pole teeth of the pole shoe and the rotating shaft decreases sequentially in the direction away from the replenishment groove.

[0008] In some embodiments, the width of the plurality of pole teeth of the pole shoe decreases sequentially in the direction away from the supplementary groove.

[0009] In some embodiments, the height of the plurality of grooves formed by the plurality of pole teeth of the pole shoe in the radial direction of the rotating shaft increases sequentially in the direction away from the supplementary groove.

[0010] In some embodiments, the tooth end faces of the plurality of pole teeth of the pole shoe are inclined surfaces, and the distance between the tooth end faces of the plurality of pole teeth and the rotating shaft in the radial direction of the rotating shaft decreases sequentially in the direction away from the supplementary groove.

[0011] In some embodiments, there are multiple replenishment slots, and at least some of the multiple replenishment slots are spaced apart in the circumferential direction of the rotating shaft.

[0012] In some embodiments, the pole shoe includes a first pole shoe and a second pole shoe, and the supplementary groove is located between the first pole shoe and the second pole shoe in the axial direction of the rotating shaft. The magnetism of the plurality of pole teeth of the first pole shoe increases in a stepwise manner away from the supplementary groove, and the magnetism of the plurality of pole teeth of the second pole shoe increases in a stepwise manner away from the supplementary groove.

[0013] In some embodiments, there are multiple pole shoes, which are spaced apart along the axial direction of the rotating shaft. There are multiple sets of replenishment slots, each set of replenishment slots including at least one replenishment slot. The multiple sets of replenishment slots correspond one-to-one with the multiple pole shoes, and the replenishment slots are arranged adjacent to the corresponding pole shoes.

[0014] In some embodiments, the supplementary groove is radially opposite to the pole tooth at the center of the corresponding pole shoe.

[0015] In some embodiments, the diameter of the opening is 0.4mm-2mm. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the self-replenishing magnetic liquid sealing device according to an embodiment of the present invention.

[0017] Figure 2 yes Figure 1 Enlarged diagram of point A in the middle.

[0018] Figure 3 This is a schematic diagram of the structure of a self-replenishing magnetic liquid sealing device according to another embodiment of the present invention.

[0019] Figure 4 yes Figure 3 Enlarged diagram of point B in the middle.

[0020] Figure 5 This is a schematic diagram of the structure of a self-replenishing magnetic liquid sealing device according to another embodiment of the present invention.

[0021] Figure 6 yes Figure 5 Enlarged diagram of point C in the middle.

[0022] Figure 7 This is a schematic diagram of the structure of a self-replenishing magnetic liquid sealing device according to another embodiment of the present invention.

[0023] Figure 8 yes Figure 7 Enlarged diagram of point D in the middle.

[0024] Figure 9 This is a schematic diagram of the structure of a self-replenishing magnetic liquid sealing device according to another embodiment of the present invention.

[0025] Figure 10 This is a cross-sectional view (AA) of the rotating shaft according to an embodiment of the present invention.

[0026] Figure 11 This is a cross-sectional view of the rotating shaft according to another embodiment of the present invention.

[0027] Figure label:

[0028] Self-replenishing magnetic liquid sealing device 100

[0029] Shell 1, Chamber 11

[0030] Rotating shaft 2, replenishment groove 21, first replenishment groove 211, second replenishment groove 212, opening 22,

[0031] Polar shoe 3, first polar shoe 31, second polar shoe 32, polar tooth 33, tooth groove 331, magnetic fluid 34.

[0032] Permanent magnet 4, first bearing 51, second bearing 52, first sleeve 61, second sleeve 62 Detailed Implementation

[0033] 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.

[0034] like Figure 1-9 As shown, the self-replenishing magnetic liquid sealing device 100 of this embodiment of the invention includes a housing 1, a rotating shaft 2, and at least one pole shoe 3.

[0035] The housing 1 has a chamber 11. A rotating shaft 2 passes through the chamber 11 and is rotatable relative to the housing 1. The two ends of the rotating shaft 2 extend from both sides of the chamber 11. The rotating shaft 2 is provided with at least one replenishment groove 21 for containing spare magnetic liquid. The circumferential surface of the rotating shaft 2 is provided with an opening 22 communicating with the replenishment groove 21.

[0036] The pole shoe 3 is fitted onto the rotating shaft 2 and located within the chamber 11. The pole shoe 3 is connected to the housing 1. The inner circumferential surface of the pole shoe 3 is provided with multiple pole teeth 33 spaced apart along the axial direction of the rotating shaft 2. A tooth groove 331 is formed between adjacent pole teeth 33, and a sealing gap is formed between the pole teeth 33 and the outer circumferential surface of the rotating shaft 2. The pole teeth 33 are magnetic, and a magnetic liquid 34 is adsorbed within the sealing gap. The magnetic liquid 34 is adsorbed onto the tooth end face of the pole teeth 33 and contacts the outer circumferential surface of the rotating shaft 2, thereby achieving a sealing function.

[0037] In this design, the magnetism of the multiple pole teeth 33 of the pole shoe 3 increases in a stepped manner towards the direction away from the replenishment tank 21. When the shaft 2 rotates, the magnetic liquid in the replenishment tank 21 flows out from the opening 22 under the action of centrifugal force and is replenished into the sealing gap of the multiple pole teeth 33 under the attraction of the pole teeth 33. In other words, the magnetism of the multiple pole teeth 33 of the pole shoe 3 increases in a stepped manner, and the magnetism of the pole teeth 33 away from the replenishment tank 21 is greater than that of the pole teeth 33 relatively close to the replenishment tank 21. When the magnetic liquid in the sealing gap decreases, under the action of centrifugal force, the magnetic liquid flows out from the replenishment tank 21. Under the action of the gradient magnetic field force, the magnetic liquid is preferentially attracted to the sealing gap of the pole tooth 33 furthest from the replenishment tank 21, that is, the sealing gap of the pole tooth 33 with the strongest magnetism, until the magnetic liquid in the sealing gap reaches a saturated state. Then, the sealing gaps of the remaining pole teeth 33 of the pole shoe 3 are gradually filled in sequence until a saturated state is reached.

[0038] The self-replenishing magnetic liquid sealing device of this invention can automatically replenish the magnetic liquid in the sealing gap, effectively solving the problem of magnetic liquid evaporation and improving the sealing reliability and service life of the magnetic liquid sealing device. This device utilizes a magnetic field strength gradient to fill the sealing gap with magnetic liquid, reducing the number of replenishment tanks required, lowering manufacturing difficulty, and improving device reliability. The device can automatically replenish the magnetic liquid in the sealing gap without the need for external sensors, further enhancing reliability. Designing the magnetic liquid replenishment tank on the rotating shaft saves axial installation space and allows for automatic replenishment or replacement of the magnetic liquid without disassembling or opening the sealing device, reducing maintenance costs and downtime, and improving sealing effect and equipment safety.

[0039] The following is based on Figures 1-11 Specific embodiments of the present invention are described below.

[0040] exist Figure 1 and Figure 2 In the illustrated embodiment, the self-replenishing magnetic fluid sealing device 100 has two pole shoes 3, including a first pole shoe 31 and a second pole shoe 32. The first pole shoe 31 and the second pole shoe 32 are spaced apart axially on the rotating shaft 2, with the first pole shoe 31 located to the left of the second pole shoe 32. Both the first pole shoe 31 and the second pole shoe 32 are annular, with their outer circumferential surfaces connected to the housing 1 and relatively stationary. When the rotating shaft 2 rotates, relative movement occurs between the rotating shaft 2 and the first pole shoe 31 and the second pole shoe 32, and the magnetic fluid is maintained in the sealing gap between the first pole shoe 31 and the rotating shaft 2, and in the sealing gap between the second pole shoe 32 and the rotating shaft 2.

[0041] The self-replenishing magnetic liquid sealing device 100 includes a permanent magnet 4, which is located axially between the first pole piece 31 and the second pole piece 32 of the rotating shaft 2. Since the first pole piece 31 and the second pole piece 32 are made of magnetically conductive materials, the magnetic field lines of the permanent magnet 4 pass through the first pole piece 31 and the second pole piece 32, making both the first pole piece 31 and the second pole piece 32 magnetic. As a result, the magnetic liquid 34 used for sealing can be adsorbed at the pole teeth 33 of the first pole piece 31 and the second pole piece 32.

[0042] Specifically, the permanent magnet 4 has a first end (left end) and a second end (right end) opposite each other along the axial direction of the rotating shaft 2. The first end of the permanent magnet 4 abuts against the first pole piece 31, making the first pole piece 31 magnetic. The second end of the permanent magnet 4 abuts against the second pole piece 32, making the second pole piece 32 magnetic. In other words, a magnetic circuit is formed between the permanent magnet 4, the first pole piece 31, the second pole piece 32, and the rotating shaft 2. Under the action of the magnetic field, the magnetic fluid is adsorbed into the sealed gap.

[0043] Optionally, the permanent magnet 4 is ring-shaped, or the permanent magnet 4 is multiple permanent magnet blocks arranged sequentially around the circumference of the rotating shaft 2, and each permanent magnet block abuts against each of the first pole piece 31 and the second pole piece 32 to provide magnetism to the pole piece 3.

[0044] In other alternative embodiments, the number of pole shoes 3 and their arrangement with the permanent magnets 4 can be different, and the present invention does not limit this.

[0045] Furthermore, such as Figure 1 As shown, the self-replenishing magnetic liquid sealing device 100 also includes a first bearing 51, a second bearing 52, a first sleeve 61, and a second sleeve 62. The first bearing 51, the second bearing 52, the first sleeve 61, and the second sleeve 62 are all located within the chamber 11 of the housing 1.

[0046] The first bearing 51 and the second bearing 52 are both supported between the housing 1 and the rotating shaft 2, supporting the rotation of the rotating shaft 2 relative to the housing 1. Each of the first pole shoe 31, the permanent magnet 4, and the second pole shoe 32 is located axially between the first bearing 51 and the second bearing 52 on the rotating shaft 2, with the second bearing 52 located away from the sealed container relative to the first bearing 51.

[0047] like Figure 1 As shown, the first sleeve 61 is axially supported between the first pole shoe 31 and the first bearing 51 on the rotating shaft 2, and the first sleeve 61 is made of a non-magnetic material. The second sleeve 62 is axially supported between the second pole shoe 32 and the second bearing 52 on the rotating shaft 2, and the second sleeve 62 is also made of a non-magnetic material. The arrangement of the first sleeve 61 and the second sleeve 62 prevents the first bearing 51 and the second bearing 52 from affecting the magnetic field and causing magnetic field leakage.

[0048] exist Figure 1 and Figure 2 In the illustrated embodiment, there are two replenishment slots 21: a first replenishment slot 211 and a second replenishment slot 212, which are spaced apart axially from the rotating shaft 2. The first replenishment slot 211 is adjacent to the first pole shoe 31 and located to the left of the first pole shoe 31, while the second replenishment slot 212 is adjacent to the second pole shoe 32 and located to the right of the second pole shoe 32.

[0049] The width of the sealing gap formed between the multiple pole teeth 33 of the first pole shoe 31 and the rotating shaft 2 decreases sequentially in the direction away from the first replenishing groove 211. The width of the sealing gap refers to the radial dimension of the sealing gap on the rotating shaft 2. Figure 1As shown, the width of the sealing gap formed by the multiple pole teeth 33 of the first pole shoe 31 gradually decreases from left to right. The smaller the width of the sealing gap, the greater the magnetic field strength generated at the sealing gap. Therefore, a gradient magnetic field with gradually increasing magnetic field strength is generated between the first pole shoe 31 and the rotating shaft 2 from left to right. In the axial direction of the rotating shaft 2, the width of the sealing gap formed between the pole tooth 33 furthest from the first replenishment groove 211 (the rightmost pole tooth 33 of the first pole shoe 31) and the rotating shaft 2 is the smallest, and the magnetic field strength generated at this sealing gap is the largest. When the magnetic fluid in the sealing gap between the first pole shoe 31 and the rotating shaft 2 decreases, the magnetic fluid in the first replenishment groove 211 flows out from the opening 22 of the first replenishment groove 211 under the action of centrifugal force. Under the action of the gradient magnetic field of the first pole shoe 31, the magnetic fluid flows from left to right, ensuring that the sealing gap of each pole tooth 33 is filled with magnetic fluid.

[0050] The width of the sealing gap formed between the multiple pole teeth 33 of the second pole shoe 32 and the rotating shaft 2 decreases sequentially away from the second replenishment groove 212. The width of the sealing gap formed by the multiple pole teeth 33 of the second pole shoe 32 gradually decreases from right to left, generating a gradient magnetic field between the second pole shoe 32 and the rotating shaft 2 with a gradually increasing magnetic field strength from right to left. Along the axial direction of the rotating shaft 2, the width of the sealing gap formed between the pole tooth 33 furthest from the second replenishment groove 212 (the leftmost pole tooth 33 of the second pole shoe 32) and the rotating shaft 2 is the smallest, and the magnetic field strength generated at this sealing gap is the largest. When the magnetic fluid in the sealing gap between the second pole shoe 32 and the rotating shaft 2 decreases, the magnetic fluid in the second replenishment groove 212 flows out from the opening 22 of the second replenishment groove 212 under the action of centrifugal force. Under the action of the gradient magnetic field of the second pole shoe 32, the magnetic fluid flows from right to left, ensuring that the sealing gap of each pole tooth 33 is filled with magnetic fluid.

[0051] exist Figure 1 and Figure 2 In the embodiment shown, there is one first replenishment slot 211 and one second replenishment slot 212, as shown. Figure 10 As shown.

[0052] In other embodiments, the number of first replenishment slots 211 and second replenishment slots 212 can be multiple, such as... Figure 11 As shown, there can be multiple first replenishment slots 211, and the multiple first replenishment slots 211 are arranged at circumferential intervals around the rotating shaft 2.

[0053] The number of second supplementary slots 212 can also be multiple, and the multiple second supplementary slots 212 are arranged at circumferential intervals around the rotating shaft 2.

[0054] It should be noted that in other embodiments, the number of pole shoes 3 and the number of replenishing grooves 21 can be different, such as one, three, four, etc. When there are multiple pole shoes 3, the multiple pole shoes 3 are spaced apart in the axial direction of the rotating shaft 2, and there are multiple sets of replenishing grooves 21, each set of replenishing grooves 21 including at least one replenishing groove 21. The multiple sets of replenishing grooves 21 correspond one-to-one with the multiple pole shoes 3, and the replenishing grooves 21 are set adjacent to the corresponding pole shoes 3. The width of the sealing gap between the multiple pole teeth 33 of the pole shoe 3 and the rotating shaft 2 decreases sequentially in the direction away from the corresponding replenishing groove 21.

[0055] exist Figure 3 and Figure 4 In the illustrated embodiment, the self-replenishing magnetic liquid sealing device 100 has two pole shoes 3, including a first pole shoe 31 and a second pole shoe 32, and the replenishment groove 21 includes a first replenishment groove 211 and a second replenishment groove 212. The arrangement of the internal components of the housing 1 of the self-replenishing magnetic liquid sealing device 100 can be referred to the above description. Figure 1 The description of the illustrated embodiments is omitted here; only the differences are described.

[0056] In this embodiment, the widths of the plurality of pole teeth 33 of the first pole shoe 31 decrease sequentially in the direction away from the first replenishment groove 211. The widths of the plurality of pole teeth 33 of the second pole shoe 32 decrease sequentially in the direction away from the second replenishment groove 212. The width of the pole tooth 33 refers to the dimension of the pole tooth 33 in the axial direction of the rotating shaft 2.

[0057] Specifically, such as Figure 4 As shown, the width of the multiple pole teeth 33 of the first pole shoe 31 gradually decreases from left to right. The smaller the width of the pole teeth 33, the greater the magnetic field strength generated at the sealing gap. Therefore, a gradient magnetic field with gradually increasing magnetic field strength is generated between the first pole shoe 31 and the rotating shaft 2 from left to right. In the axial direction of the rotating shaft 2, the pole tooth 33 furthest from the first replenishment groove 211 (the rightmost pole tooth 33 of the first pole shoe 31) has the smallest width, and the magnetic field strength generated at this sealing gap is the largest. When the magnetic fluid in the sealing gap between the first pole shoe 31 and the rotating shaft 2 decreases, the magnetic fluid in the first replenishment groove 211 flows out from the opening 22 of the first replenishment groove 211 under the action of centrifugal force. Under the action of the gradient magnetic field of the first pole shoe 31, the magnetic fluid flows from left to right, ensuring that the sealing gap of each pole tooth 33 is filled with magnetic fluid.

[0058] The width of the multiple pole teeth 33 of the second pole shoe 32 gradually decreases from right to left, generating a gradient magnetic field between the second pole shoe 32 and the rotating shaft 2 with the magnetic field strength gradually increasing from right to left. The leftmost pole tooth 33 of the second pole shoe 32 has the smallest width, and the magnetic field strength generated at this sealing gap is the largest.

[0059] It should be noted that in other embodiments, the number of pole shoes 3 and the number of replenishment grooves 21 can be different, such as one, three, four, etc. The width of the multiple pole teeth 33 of the pole shoes 3 decreases sequentially in the direction away from the corresponding replenishment grooves 21. A gradient magnetic field with progressively increasing magnetic field strength is generated between the pole shoes 3 and the rotating shaft 2 in the direction away from the corresponding replenishment grooves 21, causing the magnetic fluid to flow in the direction away from the corresponding replenishment grooves 21, so as to ensure that the sealing gap of each pole tooth 33 is filled with magnetic fluid.

[0060] exist Figure 5 and Figure 6 In the illustrated embodiment, the self-replenishing magnetic liquid sealing device 100 has two pole shoes 3, including a first pole shoe 31 and a second pole shoe 32, and the replenishment groove 21 includes a first replenishment groove 211 and a second replenishment groove 212. The arrangement of the internal components of the housing 1 of the self-replenishing magnetic liquid sealing device 100 can be referred to the above description. Figure 1 The description of the illustrated embodiments is omitted here; only the differences are described.

[0061] In this embodiment, the height of the plurality of grooves 331 formed by the plurality of pole teeth 33 of the first pole shoe 31 increases sequentially in the direction away from the first supplementary groove 211. The height of the plurality of grooves 331 formed by the plurality of pole teeth 33 of the second pole shoe 32 increases sequentially in the direction away from the second supplementary groove 212. The height of the groove 331 is its radial dimension on the rotating shaft 2.

[0062] Specifically, such as Figure 6 As shown, the height of the multiple grooves 331 of the first pole piece 31 gradually increases from left to right. Therefore, the center height of the multiple pole teeth 33 of the first pole piece 31 gradually increases from left to right. The higher the height of the pole teeth 33, the greater the magnetic field strength generated at the sealing gap. Thus, a gradient magnetic field with progressively increasing magnetic field strength is generated between the first pole piece 31 and the rotating shaft 2. In the axial direction of the rotating shaft 2, the pole tooth 33 furthest from the first replenishment groove 211 (the rightmost pole tooth 33 of the first pole piece 31) has the highest height, and the magnetic field strength generated at this sealing gap is the greatest. When the magnetic fluid in the sealing gap between the first pole piece 31 and the rotating shaft 2 decreases, the magnetic fluid in the first replenishment groove 211 flows out from the opening 22 of the first replenishment groove 211 under the action of centrifugal force. Under the action of the gradient magnetic field of the first pole piece 31, the magnetic fluid flows from left to right, ensuring that the sealing gap of each pole tooth 33 is filled with magnetic fluid.

[0063] The height of the multiple grooves 331 of the second pole shoe 32 gradually increases from right to left, generating a gradient magnetic field between the second pole shoe 32 and the rotating shaft 2 with the magnetic field strength gradually increasing from right to left. The center height of the leftmost pole tooth 33 of the second pole shoe 32 is the highest, and the magnetic field strength generated at this sealing gap is the greatest.

[0064] It should be noted that in other embodiments, the number of pole shoes 3 and the number of replenishment grooves 21 can be different, such as one, three, four, etc. The height of the multiple grooves 331 formed by the multiple pole teeth 33 of the pole shoe 3 increases sequentially in the radial direction away from the corresponding replenishment groove 21. A gradient magnetic field with progressively increasing magnetic field strength is generated between the pole shoe 3 and the rotating shaft 2 in the direction away from the corresponding replenishment groove 21, so that the magnetic fluid flows away from the corresponding replenishment groove 21, thereby ensuring that the sealing gap of each pole tooth 33 is filled with magnetic fluid.

[0065] exist Figure 7 and Figure 8 In the illustrated embodiment, the self-replenishing magnetic liquid sealing device 100 has two pole shoes 3, including a first pole shoe 31 and a second pole shoe 32, and the replenishment groove 21 includes a first replenishment groove 211 and a second replenishment groove 212. The arrangement of the internal components of the housing 1 of the self-replenishing magnetic liquid sealing device 100 can be referred to the above description. Figure 1 The description of the illustrated embodiments is omitted here; only the differences are described.

[0066] In this embodiment, the tooth end faces of the plurality of pole teeth 33 of the first pole shoe 31 are inclined surfaces, and the distance between the tooth end faces of the plurality of pole teeth 33 and the rotating shaft 2 in the radial direction of the rotating shaft 2 decreases sequentially away from the first supplementary groove 211. The tooth end faces of the plurality of pole teeth 33 of the second pole shoe 32 are inclined surfaces, and the distance between the tooth end faces of the plurality of pole teeth 33 and the rotating shaft 2 in the radial direction of the rotating shaft 2 decreases sequentially away from the second supplementary groove 212. In other words, the width (radial dimension of the rotating shaft 2) of the sealing gap formed between the pole teeth 33 and the rotating shaft 2 decreases sequentially away from the corresponding supplementary groove 21. The smaller the width, the greater the magnetic field strength generated at the sealing gap. Therefore, a gradient magnetic field with gradually increasing magnetic field strength is generated between the first pole shoe 31 and the rotating shaft 2 from left to right, and a gradient magnetic field with gradually increasing magnetic field strength is generated between the second pole shoe 32 and the rotating shaft 2 from right to left.

[0067] It should be noted that in other embodiments, the number of pole shoes 3 and the number of supplementary grooves 21 can be different, such as one, three, four, etc. The tooth end faces of the multiple pole teeth 33 of the pole shoe 3 are inclined surfaces, and the distance between the tooth end faces of the multiple pole teeth 33 and the rotating shaft 2 in the radial direction of the rotating shaft decreases sequentially in the direction away from the corresponding supplementary groove 21.

[0068] In some embodiments, there are multiple replenishment slots 21, and at least some of the multiple replenishment slots 21 are spaced apart in the circumferential direction of the rotating shaft 2.

[0069] In some embodiments, such as Figure 9As shown, the pole piece 3 includes a first pole piece 31 and a second pole piece 32. The supplementary groove 21 is located between the first pole piece 31 and the second pole piece 32 in the axial direction of the rotating shaft 2. The magnetism of the plurality of pole teeth 33 of the first pole piece 31 increases in a stepwise manner away from the supplementary groove 21, and the magnetism of the plurality of pole teeth 33 of the second pole piece 32 also increases in a stepwise manner away from the supplementary groove 21. The first pole piece 31 and the second pole piece 32 can form a gradient magnetic field using any of the methods described in the above embodiments.

[0070] In some embodiments, there are multiple pole shoes 3, which are spaced apart axially on the rotating shaft 2. There are multiple sets of replenishment grooves 21, each set including at least one replenishment groove 21. Each set of replenishment grooves 21 corresponds one-to-one with a single pole shoe 3, and the replenishment groove 21 is positioned adjacent to its corresponding pole shoe 3. The replenishment groove 21 is radially opposite to the pole teeth 33 at the center of the corresponding pole shoe 3. A portion of the pole teeth 33 of the pole shoe 3 is located on the left side of the replenishment groove 21, and a portion is located on the right side. The pole teeth 33 on the left side of the replenishment groove 21 form a gradient magnetic field that increases progressively from right to left, while the pole teeth 33 on the right side of the replenishment groove 21 form a gradient magnetic field that increases progressively from left to right. A portion of the magnetic fluid flowing from the replenishment groove 21 flows from left to right, and another portion flows from right to left, ultimately filling the various sealing gaps of the pole shoes 3, thus achieving self-replenishment of the magnetic fluid.

[0071] Optionally, the diameter of the opening 22 on the rotating shaft 2 is 0.4mm-2mm. If the diameter of the opening 22 is too large, for example, greater than 2mm, the outflow velocity of the magnetic liquid will be too high, and the loss will be too fast. The outflow rate of the magnetic liquid from the replenishment tank 21 will be greater than the flow rate of the magnetic liquid along the axial direction of the rotating shaft 2, which may lead to the loss of magnetic liquid. If the diameter of the opening 22 is too small, for example, less than 0.4mm, the outflow of the magnetic liquid from the replenishment tank 21 will be restricted, which may affect the self-replenishment effect.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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 self-replenishing magnetic liquid sealing device, characterized in that, include: case; A rotating shaft passes through the housing and is rotatable relative to the housing. The rotating shaft has at least one replenishment groove for holding spare magnetic liquid. The rotating shaft has an opening on its circumferential surface that communicates with the replenishment groove. At least one pole shoe is provided, which is fitted onto the rotating shaft and located in the cavity of the housing. The pole shoe is connected to the housing. The inner circumferential surface of the pole shoe is provided with a plurality of pole teeth spaced apart in the axial direction of the rotating shaft. A tooth groove is formed between adjacent pole teeth. A sealing gap is formed between the pole teeth and the outer circumferential surface of the rotating shaft. The pole teeth are magnetic and magnetic liquid is adsorbed in the sealing gap. The magnetism of the multiple pole teeth of the pole shoe increases in a stepwise manner away from the replenishment groove. When the shaft rotates, the magnetic liquid in the replenishment groove flows out from the opening under the action of centrifugal force and is replenished into the sealing gap of the multiple pole teeth under the attraction of the pole teeth. At least one of the following methods is used to make the magnetism of the plurality of pole teeth of the pole shoe increase in a stepwise manner away from the replenishment groove: The width of the sealing gap between the plurality of pole teeth of the pole shoe and the rotating shaft decreases sequentially in the direction away from the replenishment groove; The width of the plurality of pole teeth of the pole shoe decreases sequentially in the direction away from the supplementary groove; The height of the multiple grooves formed by the multiple pole teeth of the pole shoe in the radial direction of the rotating shaft increases sequentially in the direction away from the supplementary groove; The tooth end faces of the plurality of pole teeth of the pole shoe are inclined, and the distance between the tooth end faces of the plurality of pole teeth and the rotating shaft in the radial direction of the rotating shaft decreases sequentially in the direction away from the supplementary groove.

2. The self-replenishing magnetic liquid sealing device according to claim 1, characterized in that, There are multiple replenishment slots, and at least some of the multiple replenishment slots are spaced apart in the circumferential direction of the rotating shaft.

3. The self-replenishing magnetic liquid sealing device according to any one of claims 1-2, characterized in that, The pole piece includes a first pole piece and a second pole piece. The supplementary groove is located between the first pole piece and the second pole piece in the axial direction of the rotating shaft. The magnetism of the multiple pole teeth of the first pole piece increases in a stepwise manner away from the supplementary groove, and the magnetism of the multiple pole teeth of the second pole piece increases in a stepwise manner away from the supplementary groove.

4. The self-replenishing magnetic liquid sealing device according to any one of claims 1-2, characterized in that, There are multiple pole shoes, which are spaced apart along the axial direction of the rotating shaft. There are multiple sets of replenishment slots, each set of replenishment slots including at least one replenishment slot. The multiple sets of replenishment slots correspond one-to-one with the multiple pole shoes, and the replenishment slots are set adjacent to the corresponding pole shoes.

5. The self-replenishing magnetic liquid sealing device according to claim 4, characterized in that, The supplementary groove is opposite to the pole tooth at the center of the corresponding pole shoe in the radial direction of the rotating shaft.

6. The self-replenishing magnetic liquid sealing device according to claim 1, characterized in that, The diameter of the opening is 0.4mm-2mm.

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