Double-dispersion magnetorheological fluid sealing structure with adjustable sealing state

Abstract

The invention discloses a double-dispersion magnetorheological fluid sealing structure with an adjustable sealing state. The double-dispersion magnetorheological fluid sealing structure comprises a sealing structure used for conducting magnetism and constructing a magnetic path, a magnetic source structure used for providing a magnetic field and an auxiliary structure used for auxiliary sealing. The double-dispersion magnetorheological fluid is formed by mixing the nano-scale magnetic particles and the micron-scale magnetic particles, and the defects that when the nano-scale magnetic particles act independently, the pressure resistance and controllability are poor, and when the micron-scale magnetic particles act independently, the leakproofness is poor are overcome; the coil provides a variable magnetic field, the permanent magnet provides a basic magnetic field, it can be guaranteed that magnetorheological fluid is bound in the sealing structure through the permanent magnet, a sealing ring is formed, the direction and size of the magnetic field at a sealing gap are changed by controlling the current of the coil, the aggregation state of magnetic particles is controlled, and therefore the pressure intensity difference of different intensities is dealt with; the combined magnetic source mode of the permanent magnets and the coils ensures that the magnetic field is adjustable on the basis of a basic sealed magnetic field, and the applicability of magnetorheological fluid sealing equipment is improved.

Description

Technical Field

[0001] This invention relates to a sealing structure, specifically a dual-dispersion magnetorheological fluid sealing structure with adjustable sealing state, belonging to the field of magnetorheological fluid sealing technology. Background Technology

[0002] Generally, rotary shaft seals include packing seals, mechanical seals, labyrinth seals, dry gas seals, and magnetorheological fluid (MRF) seals. Among these, MRF seals utilize a magnetic circuit design to confine the MRF between the pole piece and the rotating shaft under the influence of a magnetic field, thus achieving a sealing effect. MRF is a novel composite material mainly composed of magnetic particles, a base fluid, and a dispersant. MRF exhibits excellent controllability; under the influence of a magnetic field, it rapidly exhibits controllable changes in viscosity and shear stress, the magnitude of which is related to the strength of the applied magnetic field. After the magnetic field is removed, it quickly transforms from a solid-like state into a Newtonian fluid. This change is reversible and responsive, completing within milliseconds. Compared to other sealing methods, MRF seals offer advantages such as non-contact sealing with low wear, long lifespan, simple structure, cleanliness, and bidirectional sealing capabilities, gradually becoming a preferred choice in the field of rotary seals.

[0003] Existing technologies for magnetorheological fluids prepared from traditional magnetic particles still have some shortcomings: nanoscale particles have high sealing performance, but are essentially liquid, resulting in poor pressure resistance and controllability; micron-sized particles have good pressure resistance and controllability, but under the influence of a magnetic field, they form clustered magnetic brush structures along the magnetic field lines, resulting in large gaps between magnetic chains and poor sealing under high pressure. Furthermore, changes in the sealing gap between the pole piece and the rotating shaft significantly affect the sealing performance; nanoscale magnetic particles are highly sensitive to changes in this gap, and even slight changes can lead to seal failure. Therefore, it is necessary to develop a novel magnetorheological fluid to compensate for the performance differences between the two types of magnetic particles.

[0004] In addition, since magnetorheological fluid seals are dynamic seals, the equipment is prone to fatigue aging due to rotational friction, which leads to a decline in sealing performance. Furthermore, when the equipment is in extreme environments such as high or low temperatures, thermal expansion and contraction can occur, causing changes in the sealing gap. For example, when the equipment is subjected to violent vibration and impact, the pole shoe and the rotating shaft may vibrate or become misaligned, which can also cause changes in the gap and lead to leakage. Summary of the Invention

[0005] The purpose of this invention is to provide a dual-dispersion magnetorheological fluid sealing structure with adjustable sealing state to solve at least one of the above-mentioned technical problems. This structure can effectively solve the problems of poor controllability of the state of nanoscale magnetic particles and high leakage rate of micron-scale magnetic particles. It can also compensate and control the magnetorheological fluid in special situations such as equipment aging and wear, extreme environments, and violent impacts, to ensure stable operation of the equipment.

[0006] To achieve the above objectives, the present invention employs the following technical solution: a dual-dispersion magnetorheological fluid sealing structure with adjustable sealing state, the dual-dispersion magnetorheological fluid sealing structure comprising: A sealing structure for conducting magnetism and constructing magnetic pathways, comprising a rotating shaft, pole shoes, and a bidispersed magnetorheological fluid filling the space between them; A magnetic source structure used to provide a magnetic field, comprising a coil and a permanent magnet; The auxiliary structure used for auxiliary sealing includes an end cap, bearing, magnetic shielding ring, O-ring, internal threaded ring, and housing; The housing is fitted onto the outside of the rotating shaft, while the pole shoes, coil, permanent magnet, bearing, and magnetic shielding ring are all fitted onto the rotating shaft. The pole shoes, coil, permanent magnet, internal thread ring, bearing, and magnetic shielding ring are all located in the gap between the housing and the rotating shaft, and an end cap is fixedly connected to the end of the housing.

[0007] As a further embodiment of the present invention: the pole shoe includes a first pole shoe and a second pole shoe, the first pole shoe and the second pole shoe surround the rotating shaft to form a sealed gap, and the sealed gap is filled with a bidispersed magnetorheological fluid; The bidispersed magnetorheological fluid is composed of nanoscale magnetic particles, micrometer-scale magnetic particles, a base liquid, and a dispersant.

[0008] As a further embodiment of the present invention: the first pole shoe, the second pole shoe, and the rotating shaft are all made of magnetic materials, including but not limited to 2Cr13 and iron.

[0009] As a further aspect of the present invention, pole teeth are provided at the positions corresponding to the first pole shoe and the second pole shoe on the rotating shaft.

[0010] As a further aspect of the present invention: the bidispersed magnetorheological fluid forms a sealing ring structure similar to an O-ring under the action of a magnetic field, and the number of sealing ring structures depends on the number of pole teeth opened on the rotating shaft.

[0011] As a further embodiment of the present invention: the magnetic source structure is located between the first pole shoe and the second pole shoe, the coil and the permanent magnet are in parallel contact, and the contact surface between the coil and the first pole shoe is smooth and flat, and the contact surface between the permanent magnet and the second pole shoe is smooth and flat.

[0012] As a further embodiment of the present invention: the housing has a through hole for placing the wire on the inner wall in contact with the coil.

[0013] As a further embodiment of the present invention: the magnetic shielding ring includes a first magnetic shielding ring and a second magnetic shielding ring, wherein the first magnetic shielding ring is located above the first pole shoe and the second magnetic shielding ring is located below the second pole shoe; The first magnetic shielding ring, the second magnetic shielding ring, the internal threaded ring, and the housing are all made of non-magnetic materials, including but not limited to 304 stainless steel and titanium alloy.

[0014] As a further embodiment of the present invention: the bearing located outside the magnetic shielding ring includes a first bearing and a second bearing, and both the first bearing and the second bearing are grooved bearings, with the inner and outer rings of the first bearing and the second bearing respectively tightly attached to the rotating shaft and the housing.

[0015] As a further embodiment of the present invention: the O-ring includes a first O-ring and a second O-ring, wherein the first O-ring is fitted in the outer groove of the first bearing, the second O-ring is fitted in the outer groove of the second bearing, and both the first O-ring and the second O-ring are tightly attached to the inner wall of the housing. The end cap is located on the outside of the second bearing and is connected to the housing.

[0016] The beneficial effects of this invention are: 1) The bidisperse magnetorheological fluid proposed in this invention is composed of a thorough mixture of nano-sized magnetic particles and micro-sized magnetic particles, which solves the shortcomings of poor pressure resistance and controllability when nano-sized magnetic particles act alone and poor tightness when micro-sized magnetic particles act alone. 2) The coil of the magnetic source structure of this invention provides a variable magnetic field, and the permanent magnet of the magnetic source structure provides a basic magnetic field. The permanent magnet can ensure that the magnetorheological fluid is "bound" in the sealed structure to form a sealing ring. By controlling the coil current, the direction and magnitude of the magnetic field at the sealing gap can be changed, and the aggregation state of the magnetic particles can be controlled to cope with pressure differences of different intensities. The combination of permanent magnet and coil magnetic source method ensures the basic sealing magnetic field and realizes the adjustment of the magnetic field, which improves the applicability of magnetorheological fluid sealing equipment. Compared with the working mode of single coil operation, it realizes the dynamic adjustment of the sealing state. At the same time, it can also compensate and control the magnetorheological fluid under special conditions, ensuring stable operation of the equipment and extending the service life of the equipment. Attached Figure Description

[0017] Figure 1 A schematic diagram of a dual-dispersion magnetorheological fluid sealing structure with adjustable sealing conditions; Figure 2 A control framework diagram for the sealing state under different conditions; Figure 3 A microscopic mechanism diagram of a magnetorheological fluid sealing structure; In the diagram: 1. Housing, 2. First bearing, 3. First magnetic shielding ring, 4. First pole shoe, 5. Coil, 6. Permanent magnet, 7. Second pole shoe, 8. Second bearing, 9. Rotating shaft, 10. First O-ring, 11. Internal threaded ring, 12. Through hole, 13. Second magnetic shielding ring, 14. Second O-ring, 15. End cap. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1, as Figures 1 to 3 As shown, this embodiment provides a dual-dispersion magnetorheological fluid sealing structure with adjustable sealing state. The dual-dispersion magnetorheological fluid sealing structure includes a sealing structure for conducting magnetism and constructing a magnetic path, a magnetic source structure for providing a magnetic field, and an auxiliary structure for assisting sealing. The sealing structure includes a rotating shaft 9, pole shoes, and dual-dispersion magnetorheological fluid filling the space between them. The magnetic source structure includes a coil 5 and a permanent magnet 6. The auxiliary structure includes an end cap 15, a bearing, a magnetic isolation ring, an O-ring, an internal threaded ring 11, and a housing 1. In addition, the housing 1 is fitted on the outside of the shaft of the rotating shaft 9; the pole shoe, coil 5, permanent magnet 6, bearing and magnetic shielding ring are all fitted on the shaft of the rotating shaft 9, and the pole shoe, coil 5, permanent magnet 6, internal thread ring 11, bearing and magnetic shielding ring are all located in the gap between the housing 1 and the rotating shaft 9; an end cap 15 is fixedly connected to the end of the housing 1.

[0020] Example 2: In addition to all the technical features in Example 1, this example also includes: the pole shoe includes a first pole shoe 4 and a second pole shoe 7, the first pole shoe 4 and the second pole shoe 7 surround the rotating shaft 9 to form a sealed gap, and the sealed gap is filled with a bidispersed magnetorheological fluid.

[0021] The pressure resistance of the dual-dispersed magnetorheological fluid seal consists of two parts: one part is the magnetization pressure generated by the magnetic properties of the magnetorheological fluid, and the other part is the yield stress generated by the elastoplastic characteristics of the magnetorheological fluid.

[0022] like Figure 3 As shown, the bidispersed magnetorheological fluid is composed of nanoscale magnetic particles, micrometer-scale magnetic particles, a base liquid, and a dispersant.

[0023] Furthermore, the first pole piece 4, the second pole piece 7, and the rotating shaft 9 are all made of magnetic materials, including but not limited to 2Cr13 and iron.

[0024] The rotating shaft 9 has pole teeth at the corresponding positions of the first pole shoe 4 and the second pole shoe 7, which serve to concentrate and guide magnetism. The shape and size of the pole teeth can be changed according to different application scenarios.

[0025] Example 3: In addition to all the technical features in Example 2, this example also includes: the bidispersed magnetorheological fluid filling the sealing gap forms a sealing ring structure similar to an O-ring under the action of a magnetic field, thereby playing a sealing role. The number of sealing ring structures depends on the number of pole teeth opened on the rotating shaft 9. This number is not unique and can be changed depending on different application scenarios.

[0026] The magnetic source structure is located between the first pole shoe 4 and the second pole shoe 7, and the coil 5 and the permanent magnet 6 of the magnetic source structure are in parallel contact. The contact surface between the coil 5 and the first pole shoe 4 is smooth and flat, and the contact surface between the permanent magnet and the second pole shoe 7 is also smooth and flat, which can effectively reduce magnetic leakage.

[0027] The coil 5 of the magnetic source structure provides a variable magnetic field, and the permanent magnet 6 of the magnetic source structure provides a basic magnetic field. The permanent magnet can ensure that the magnetorheological fluid is "bound" in the sealed structure to form a sealing ring, and the coil can change the magnitude and direction of the magnetic field in the sealing gap. The housing 1 has a through hole 12 on its inner wall that contacts the coil 5, which is used to place the coil wire and to allow the wire to pass through the through hole 12 and be connected to an external power source.

[0028] Example 4: In addition to all the technical features in Example 2, this example also includes: the magnetic isolation ring of the auxiliary structure includes a first magnetic isolation ring 3 and a second magnetic isolation ring 13. The first magnetic isolation ring 3 is close to the top of the first pole shoe 4, and the second magnetic isolation ring 13 is close to the bottom of the second pole shoe 7, so as to isolate the magnetic path. The first magnetic shielding ring 3, the second magnetic shielding ring 13, the internal threaded ring 11, and the housing 1 are all made of non-magnetic materials, including but not limited to 304 stainless steel and titanium alloy.

[0029] The internal threaded ring 11 of the auxiliary structure is tightly screwed together with the protruding threaded portion of the first pole shoe 4 and the second pole shoe 7, which can play an auxiliary sealing role and prevent the sealing medium from leaking from the through hole 12.

[0030] The auxiliary structure bearing is located on the outside of the magnetic shielding ring. The bearing includes a first bearing 2 and a second bearing 8. Both the first bearing 2 and the second bearing 8 are grooved bearings. The inner and outer rings of the first bearing 2 and the second bearing 8 are tightly attached to the rotating shaft 9 and the housing 1, respectively.

[0031] The auxiliary structure includes a first O-ring 10 and a second O-ring 14. The first O-ring 10 is fitted in the outer groove of the first bearing 2, and the second O-ring 14 is fitted in the outer groove of the second bearing 8. Both the first O-ring 10 and the second O-ring 14 are tightly attached to the inner wall of the housing 1, which can play an auxiliary sealing role and prevent the sealing medium from leaking from the housing 1.

[0032] The end cap 15 of the auxiliary structure is located on the outside of the second bearing 14 and is connected to the housing 1 by screws.

[0033] like Figure 2 As shown, when the ambient pressure or sealing gap changes, the coil current precisely controls the aggregation state of magnetic particles by adjusting the magnetic field strength and direction at the sealing gap. For example, when the ambient temperature decreases or the sealing gap increases due to equipment aging and wear, the coil current increases to compensate; when the temperature rises and the gap decreases, the current decreases accordingly. Under the influence of the magnetic field change caused by the current change, the micron-sized magnetic particles respond rapidly due to their excellent controllability; simultaneously, the nano-sized magnetic particles move collaboratively under the influence of the micron-sized particles, and fill the gaps between the micron-sized particles with their excellent fluidity, significantly reducing the leakage rate when a single micron-sized particle is involved.

[0034] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0035] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A dual-dispersion magnetorheological fluid sealing structure with adjustable sealing state, characterized in that, include: A sealing structure for conducting magnetism and constructing magnetic pathways, the sealing structure comprising a rotating shaft (9), pole shoes, and a bidispersed magnetorheological fluid filling the space between them; A magnetic source structure for providing a magnetic field, the magnetic source structure including a coil (5) and a permanent magnet (6). An auxiliary structure for auxiliary sealing, the auxiliary structure including an end cap (15), a bearing, a magnetic shielding ring, an O-ring, an internal threaded ring (11), and a housing (1). The housing (1) is sleeved on the outside of the rotating shaft (9). The pole shoe, coil (5), permanent magnet (6), bearing and magnetic shielding ring are all sleeved on the rotating shaft (9). The pole shoe, coil (5), permanent magnet (6), internal thread ring (11), bearing and magnetic shielding ring are all located in the gap between the housing (1) and the rotating shaft (9). An end cap (15) is fixedly connected to the end of the housing (1).

2. The dual-dispersed magnetorheological fluid sealing structure according to claim 1, characterized in that: The pole shoe includes a first pole shoe (4) and a second pole shoe (7), the first pole shoe (4) and the second pole shoe (7) surround the rotating shaft (9) to form a sealed gap, and the sealed gap is filled with a bidisperse magnetorheological fluid; The bidispersed magnetorheological fluid is composed of nanoscale magnetic particles, micrometer-scale magnetic particles, a base carrier liquid, and a dispersant.

3. The dual-dispersed magnetorheological fluid sealing structure according to claim 2, characterized in that: The first pole piece (4), the second pole piece (7), and the rotating shaft (9) are all made of magnetic materials, including but not limited to 2Cr13 and iron.

4. The dual-dispersed magnetorheological fluid sealing structure according to claim 2, characterized in that: The rotating shaft (9) has pole teeth at the positions corresponding to the first pole shoe (4) and the second pole shoe (7).

5. The dual-dispersed magnetorheological fluid sealing structure according to claim 4, characterized in that: The bidispersed magnetorheological fluid forms a sealing ring structure similar to an O-ring under the action of a magnetic field, and the number of the sealing ring structures depends on the number of pole teeth opened on the rotating shaft (9).

6. The dual-dispersed magnetorheological fluid sealing structure according to claim 2, characterized in that: The magnetic source structure is located between the first pole shoe (4) and the second pole shoe (7). The coil (5) and the permanent magnet (6) are in parallel contact. The contact surface between the coil (5) and the first pole shoe (4) is smooth and flat, and the contact surface between the permanent magnet (6) and the second pole shoe (7) is smooth and flat.

7. The dual-dispersed magnetorheological fluid sealing structure according to claim 1, characterized in that: The housing (1) has a through hole (12) for placing wires on the inner wall that contacts the coil (5).

8. The dual-dispersed magnetorheological fluid sealing structure according to claim 2, characterized in that: The magnetic shielding ring includes a first magnetic shielding ring (3) and a second magnetic shielding ring (13), wherein the first magnetic shielding ring (3) is located above the first pole shoe (4), and the second magnetic shielding ring (13) is located below the second pole shoe (7); The first magnetic shielding ring (3), the second magnetic shielding ring (13), the internal thread ring (11) and the shell (1) are all made of non-magnetic materials, and the non-magnetic materials include, but are not limited to, 304 stainless steel and titanium alloy.

9. The dual-dispersed magnetorheological fluid sealing structure according to claim 1, characterized in that: The bearings located outside the magnetic shielding ring include a first bearing (2) and a second bearing (8), and both the first bearing (2) and the second bearing (8) are grooved bearings. The inner and outer rings of the first bearing (2) and the second bearing (8) are respectively in close contact with the rotating shaft (9) and the housing (1).

10. The dual-dispersed magnetorheological fluid sealing structure according to claim 9, characterized in that: The O-rings include a first O-ring (10) and a second O-ring (14), wherein the first O-ring (10) is fitted in the outer groove of the first bearing (2), and the second O-ring (14) is fitted in the outer groove of the second bearing (8), and both the first O-ring (10) and the second O-ring (14) are tightly attached to the inner wall of the housing (1). The end cap (15) is located on the outside of the second bearing (14) and is connected to the housing (1).

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