A magnetic liquid composite sealing device for centrifugal-assisted heat dissipation

Abstract

This invention belongs to the field of mechanical engineering sealing technology, specifically relating to a magnetic liquid composite sealing device with centrifugal-assisted heat dissipation. The device includes: a housing, a limiting ring I, a bearing, a rotating shaft, a bushing I, a magnet, a bushing II, a limiting ring II, and an end cap. The bushing and the magnet are fixed to the rotating shaft by an interference fit and rotate synchronously with the shaft; the pole shoe is fixed inside the housing, forming a sealing gap with the bushing, and the magnetic liquid fills this gap. This invention utilizes the principle of centrifugal sealing, using centrifugal force to press the magnetic liquid into the sealing gap at high speeds, ensuring sealing capability; simultaneously, the centrifugal sealing structure can expand the volume and heat exchange area of ​​the annular flow channel, enhancing heat dissipation capacity and adapting to high-temperature or high-speed operating conditions. This invention has a compact structure, good heat dissipation effect, and high sealing reliability, and is suitable for high-temperature and high-speed sealing applications such as aero-engines and high-speed rotating machinery.

Description

Technical Field

[0001] This invention belongs to the field of mechanical engineering sealing technology, specifically relating to a magnetic liquid composite sealing device with centrifugal assisted heat dissipation, which is particularly suitable for rotating shaft sealing under high temperature and high speed conditions such as aero-engines and high-speed rotating machinery. Background Technology

[0002] Magnetic liquid sealing is an advanced sealing technology that utilizes magnetic liquids to form a dynamic sealing layer under the action of a magnetic field. It has advantages such as zero leakage, long service life, and no solid contact wear, and is widely used in high-end equipment fields such as aerospace, nuclear energy, and semiconductors.

[0003] However, as equipment develops towards higher speeds and higher power densities, magnetic fluid seals face severe thermal management challenges. On the one hand, the viscous friction between the magnetic fluid and the shaft and pole shoes at high speeds generates a large amount of heat; on the other hand, excessively high ambient temperatures can also cause the magnetic fluid temperature to rise. Increased temperature reduces the saturation magnetization and viscosity of the magnetic fluid, accelerates the evaporation of the base fluid, and leads to a decrease in the seal's pressure resistance, or even seal failure.

[0004] In related technologies, there are solutions to enhance heat dissipation by opening cooling water tanks on the pole shoes or outer shell. However, in these solutions, the volume of the cooling water tanks is limited by the size of the pole shoes, the heat exchange area is limited, and the heat dissipation effect is difficult to meet the requirements of ultra-high speed operating conditions.

[0005] Furthermore, centrifugal force at high speeds can cause the magnetic fluid to be ejected, potentially reducing the amount of magnetic fluid within the sealing gap and affecting sealing performance. How to utilize the advantages of high speeds while avoiding their negative impacts is a pressing technical problem that needs to be solved in this field. Summary of the Invention

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

[0007] To address this, embodiments of the present invention propose a magnetic liquid composite sealing device with centrifugal-assisted heat dissipation. This device utilizes the centrifugal sealing principle to force the magnetic liquid into the sealing gap through centrifugal force at high speeds, ensuring sealing capability. Simultaneously, the centrifugal sealing structure can expand the volume and heat exchange area of ​​the annular flow channel, enhancing heat dissipation capability and adapting to high-temperature and high-speed operating conditions.

[0008] The centrifugally assisted heat dissipation magnetic liquid composite sealing device of this invention includes:

[0009] The outer casing has an inner cavity;

[0010] A rotating shaft, which can rotate about a central axis;

[0011] A bearing, disposed between the rotating shaft and the housing, is used to support the rotating shaft;

[0012] Bushing I and bushing II are both sleeved on the rotating shaft and rotate synchronously with the rotating shaft. A protrusion is provided on the left side of the rotating shaft to axially limit bushing I.

[0013] A magnet is sleeved on the rotating shaft and fixed between bushing I and bushing II by an interference fit.

[0014] The pole shoe has its inner circumferential surface facing the outer circumferential surfaces of bushing I and bushing II in the radial direction, and a sealing gap is formed between them;

[0015] A magnetic fluid, which fills the sealed gap;

[0016] End cap, the end cap being connected to the axial end of the housing;

[0017] Two annular flow channels are provided, located on opposite sides of the pole shoe along the axial direction; two inlets and two outlets are provided, located on opposite sides of the outer casing along the circumference.

[0018] Limiting ring I and limiting ring II are provided. The two limiting rings I are located on the inner side of the outer shell and are used to axially position the two sides of the pole shoe. The limiting ring II is sleeved on the rotating shaft by interference fit and rotates synchronously with the rotating shaft to axially limit the bushing I, the magnet and the bushing II.

[0019] In this embodiment of the invention, a magnetic liquid composite sealing device for centrifugal-assisted heat dissipation has a bushing and a magnet fixed to a rotating shaft by an interference fit, rotating synchronously with the shaft. At high speeds, the centrifugal force generated by the rotation acts on the magnetic liquid within the sealing gap, causing it to fill the sealing gap between the pole shoe and the bushing more tightly, thereby enhancing the sealing capability and overcoming the technical challenge of centrifugal force ejecting the magnetic liquid at high speeds.

[0020] Meanwhile, because the bushing rotates with the shaft, a larger annular flow channel can be set between the outer shell and the pole shoe. The volume and heat exchange area of ​​the annular flow channel are significantly larger than those of the traditional pole shoe cooling water tank. Cooling water enters the annular flow channel from the inlet, flows through the channel, and exits from the outlet, effectively removing heat and ensuring that the magnetic fluid operates within a suitable temperature range.

[0021] Two annular flow channels are provided, located on the axial sides of the pole shoe respectively; two inlets and two outlets are provided, located on the circumferential sides of the outer shell respectively.

[0022] The outer circumferential surfaces of bushing I and bushing II are provided with pole teeth, which are arranged at intervals along the radial and axial directions, and a sealing gap is formed between the pole teeth and the inner circumferential surface of the pole shoe.

[0023] The radial pole teeth have a right-angled trapezoidal cross-section, which facilitates the flow of magnetic fluid to the sealing gap of the centrifugal seal at high speeds, ensuring sealing capability. The axial pole teeth are rectangular in shape, with all pole teeth protruding outwards, which facilitates the use of the high centrifugal force generated by the high speed to ensure that the magnetic fluid and pole teeth are tightly adhered, thereby ensuring sealing capability. There are no pole teeth on the outer circumference of the bushings I and II directly above the magnet; this gap is used to collect magnetic fluid during centrifugal sealing.

[0024] Four sealing rings I are provided between the pole shoe and the outer shell to seal the cooling water; a sealing ring II is provided at the connection between the bushing I and the bushing II to prevent magnetic liquid from entering the connection.

[0025] The outer shell, rotating shaft, limiting ring I, limiting ring II, and end cap are all made of non-magnetic materials; the bushing I, bushing II, and pole shoe are all made of magnetic materials.

[0026] The magnet is a ring-shaped permanent magnet with its magnetic poles arranged along the axial direction, forming N poles and S poles respectively.

[0027] The annular flow channel has a rectangular cross-section. Due to the cooperation of centrifugal seals, the annular flow channel can increase the heat exchange area while still ensuring the sealing capability.

[0028] The bearings are rolling bearings or sliding bearings, and there are two of them, which are respectively located on the left side of bushing I and the right side of bushing II.

[0029] The two limiting rings I are disposed on the inner side of the outer shell to axially position the two sides of the pole shoe; the limiting ring II is sleeved on the rotating shaft by interference fit and rotates synchronously with the rotating shaft to axially limit the bushing I, the magnet and the bushing II. Beneficial effects

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. Centrifugal Assisted Sealing: By utilizing centrifugal force at high speed, the magnetic fluid is more tightly filled into the sealing gap, overcoming the technical challenge of centrifugal force throwing out the magnetic fluid at high speed and improving the sealing reliability under high speed conditions.

[0032] 2. Enhanced heat dissipation: Through the centrifugal sealing structure design, a larger annular flow channel can be set between the outer shell and the pole shoe, significantly expanding the heat exchange area, enhancing the cooling effect, ensuring that the magnetic fluid operates within a suitable temperature range, and extending the seal life.

[0033] 3. Compact structure: The bushing and magnet are fixed to the rotating shaft by interference fit and rotate synchronously with the rotating shaft. No additional connection structure is required. The axial dimensions are compact and easy to install and maintain.

[0034] 4. Wide range of applications: This invention can simultaneously solve the centrifugal force problem under high speed conditions and the heat dissipation problem under high temperature conditions, and is particularly suitable for applications with stringent sealing performance requirements such as aero engines and high-speed rotating machinery. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of the magnetic liquid composite sealing device for centrifugal assisted heat dissipation according to an embodiment of the present invention; Figure 2 This is a partial view of the pole teeth of the bushing.

[0036] Figure reference numerals:

[0037] 1-Inlet; 2-Annular flow channel; 3-Sealing ring I; 4-Magnetic fluid; 5-Outer shell; 6-Limiting ring I; 7-Bearing; 8-Shaft; 9-Sleeve I; 10-Pole shoe; 11-Sealing ring II; 12-Outlet; 13-Magnet; 14-Sleeve II; 15-Limiting ring II; 16-End cap. Detailed Implementation

[0038] 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.

[0039] like Figure 1 As shown, the centrifugal assisted heat dissipation magnetic liquid composite sealing device of the present invention includes a shell (5), a rotating shaft (8), bushing I (9), bushing II (14), a magnet (13), a pole shoe (10), a magnetic liquid (4), an end cap (16), an annular flow channel (2), a bearing (7), a limiting ring I (6) and a limiting ring II (15).

[0040] The outer shell (5) has an inner cavity, and the rotating shaft (8) can rotate around the central axis. The rotating shaft (8) is arranged coaxially with the outer shell (5).

[0041] Both bushing I (9) and bushing II (14) are fitted onto the rotating shaft (8) and rotate synchronously with it. Magnet (13) is fitted onto the rotating shaft (8) and is located between bushing I (9) and bushing II (14). Magnet (13) is fixed to bushing I (9) and bushing II (14) by an interference fit to ensure that no relative slippage occurs at high speeds.

[0042] The pole shoe (10) is installed inside the outer casing (5). The inner circumferential surface of the pole shoe (10) is radially opposite to the outer circumferential surfaces of bushing I (9) and bushing II (14), and a sealing gap is formed between them. The bushing I (9) and bushing II (14) are designed with pole teeth, specifically as follows: Figure 2 As shown. Magnetic fluid (4) fills the sealing gap and is adsorbed at the sealing gap under the action of the magnetic field formed by the magnet (13), forming a magnetic fluid sealing ring.

[0043] The end cap (16) is connected to the axial end of the outer shell (5) to close the inner cavity.

[0044] An annular flow channel (2) is located between the outer shell (5) and the pole shoe (10). The two ends of the annular flow channel (2) are respectively provided with an inlet (1) and an outlet (12). Cooling water enters the annular flow channel (2) from the inlet (1), flows through the flow channel and is discharged from the outlet (12), carrying away the heat generated by the sealing device.

[0045] The bearing (7) is located between the rotating shaft (8) and the housing (5) to support the rotating shaft (8) and ensure its rotational accuracy. In this embodiment, there are two bearings (7), which are located on the left side of the bushing I (9) and the right side of the bushing II (14).

[0046] Two limiting rings I (6) are set on the inner side of the outer shell (5) to axially position the two sides of the pole shoe (10); the limiting ring II (15) is fitted on the rotating shaft (8) by interference fit and rotates synchronously with the rotating shaft (8) to axially limit the bushing I (9), the magnet (13) and the bushing II (14).

[0047] To ensure sealing, four sealing rings I (3) are provided between the pole shoe (10) and the outer shell (5) to seal the cooling water; sealing ring II (11) is provided at the connection between the bushing I (9) and the bushing II (14) to prevent magnetic liquid (4) from entering the connection.

[0048] In this embodiment, there are two inlets (1) and two outlets (12), which are respectively located on the circumferential sides of the outer shell (5), and two annular flow channels (2) are respectively located on the axial sides of the pole shoe (10). This symmetrical arrangement makes the cooling water flow channel more uniform and the heat dissipation effect better.

[0049] Part of the outer circumferential surface of bushing I (9) and bushing II (14) is provided with pole teeth, which are arranged at intervals along the radial and axial directions respectively. A sealing gap is formed between the pole teeth and the inner circumferential surface of the pole shoe (10). The position and shape of the pole teeth are as follows: Figure 2As shown. The pole tooth structure can enhance the magnetic field gradient and improve the sealing pressure resistance. The cross-sectional shape of the radial pole tooth is a right trapezoid, which facilitates the flow of magnetic liquid (4) to the sealing gap of centrifugal seal at high speed, thus ensuring the sealing capacity; the axial pole tooth is rectangular in shape, and the pole tooth direction protrudes outward, which facilitates the use of the high centrifugal force generated by the high speed to ensure that the magnetic liquid (4) is tightly attached to the pole tooth, thereby ensuring the sealing capacity; there are no pole teeth on the outer circumference of the bushing I (9) and bushing II (14) directly above the magnet (13), and this gap is used to collect magnetic liquid (4) during centrifugal sealing.

[0050] In terms of material selection, the outer shell (5), rotating shaft (8), limiting ring I (6), limiting ring II (15), and end cap (16) are all non-magnetic materials, such as 304 stainless steel. Bushing I (9), bushing II (14), and pole shoe (10) are all magnetic materials, such as 2Cr13. The magnet (13) is a toroidal permanent magnet, preferably made of neodymium iron boron material, with its magnetic poles arranged axially to form closed magnetic circuits with bushing I (9) and bushing II (14), respectively.

[0051] The working principle of the embodiments of the present invention is explained below:

[0052] Magnetic circuit composition: The magnetic field lines emitted from the N pole of the magnet (13) pass through the bushing I (9), the magnetic fluid (4) in the sealed gap, the pole shoe (10), and then through the magnetic fluid (4) in the sealed gap on the other side and the bushing II (14), returning to the S pole of the magnet (13). The magnetic field lines form a magnetic field gradient at the pole teeth, which binds the magnetic fluid in the sealed gap.

[0053] Centrifugal Assisted Sealing: When the shaft (8) rotates at high speed, bushing I (9) and bushing II (14) rotate synchronously with the shaft. The centrifugal force generated by the rotation acts on the magnetic fluid (4) in the sealing gap, making it fill the gap between the pole shoe (10) and the pole teeth more tightly. The higher the rotation speed, the greater the centrifugal force, and the tighter the magnetic fluid fills, thus ensuring the sealing ability. At the same time, some magnetic fluid will enter the sealing gap on the outer circumference of bushing I (9) and bushing II (14) above the magnet (13) where there are no pole teeth, along the radial right-angled trapezoidal pole teeth, to accumulate magnetic fluid (4) when used for centrifugal sealing, thus providing a second layer of protection for the seal.

[0054] Heat dissipation process: Cooling water enters the annular flow channel (2) from the inlet (1), flows through the pole shoe (10), carries away the heat generated by the friction of the magnetic fluid through heat conduction, and then is discharged from the outlet (12). Since the annular flow channel (2) has a large volume and sufficient heat exchange area, it can effectively control the working temperature of the magnetic fluid (4), ensure its stable performance, and thus maintain the sealing performance under high speed conditions.

[0055] This invention combines the centrifugal sealing principle with magnetic liquid sealing, achieving the dual effects of enhanced sealing and enhanced heat dissipation at high speeds. It is particularly suitable for high-temperature and high-speed operating conditions with stringent sealing requirements, such as aero engines and high-speed rotating machinery.

[0056] Although embodiments of the present invention have been shown and described above, it is understood that these 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. Without departing from the scope of the present invention, any simple modifications, equivalent substitutions, and improvements made to the above embodiments based on the technical essence of the present invention and within the spirit and principles of the present invention, without departing from the scope of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A magnetic liquid composite sealing device for centrifugal assisted heat dissipation, comprising a housing (5), a limiting ring I (6), a bearing (7), a rotating shaft (8), a bushing I (9), a magnet (13), a bushing II (14), a limiting ring II (15), and an end cap (16). The rotating shaft (8) is disposed in the inner cavity of the housing (5) and can rotate around a central axis. The bearing (7) is disposed between the rotating shaft (8) and the housing (5) to support the rotating shaft (8). Bushing I (9) and bushing II (14) are both sleeved on the rotating shaft (8) and rotate synchronously with the rotating shaft (8). A protrusion is provided on the left side of the rotating shaft (8) to axially limit bushing I (9). The magnet (13) is sleeved on the rotating shaft (8) and fixed between bushing I (9) and bushing II (14) by interference fit. The end cap (16) is connected to the axial end of the housing (5). The device is characterized in that: An pole shoe (10) is provided inside the outer shell (5). The inner circumferential surface of the pole shoe (10) is radially opposite to the outer circumferential surfaces of bushing I (9) and bushing II (14), and a sealing gap is formed between them. The sealing gap is filled with magnetic liquid (4). An annular flow channel (2) is provided between the outer shell (5) and the pole shoe (10). The two ends of the annular flow channel (2) are respectively provided with an inlet (1) and an outlet (12).

2. The magnetic liquid composite sealing device for centrifugal assisted heat dissipation according to claim 1, characterized in that, The annular flow channel (2) is configured in two, located on the axial sides of the pole shoe (10); the inlet (1) and the outlet (12) are both two, respectively located on the circumferential sides of the outer shell (5).

3. The magnetic liquid composite sealing device for centrifugal assisted heat dissipation according to claim 1, characterized in that, The outer peripheral surfaces of bushing I (9) and bushing II (14) are provided with pole teeth, which are arranged at intervals along the radial and axial directions respectively, and a sealing gap is formed between the pole teeth and the inner peripheral surface of the pole shoe (10).

4. The magnetic liquid composite sealing device for centrifugal assisted heat dissipation according to claim 3, characterized in that, The radial pole teeth have a right-angled trapezoidal cross-section, which facilitates the flow of magnetic liquid (4) to the sealing gap of centrifugal seal at high speed, thus ensuring sealing capability. The axial pole teeth are rectangular in shape, with the pole teeth protruding outwards, which facilitates the use of the high centrifugal force generated by the high speed to ensure that the magnetic liquid (4) is tightly attached to the pole teeth, thereby ensuring sealing capability. There are no pole teeth on the outer circumference of bushing I (9) and bushing II (14) directly above the magnet (13), and this gap is used to collect magnetic liquid (4) during centrifugal sealing.

5. The magnetic liquid composite sealing device for centrifugal assisted heat dissipation according to claim 1, characterized in that, Four sealing rings I (3) are provided between the pole shoe (10) and the outer shell (5) to seal the cooling water; a sealing ring II (11) is provided at the connection between the bushing I (9) and the bushing II (14) to prevent magnetic liquid (4) from entering the connection.

6. The magnetic liquid composite sealing device for centrifugal assisted heat dissipation according to claim 1, characterized in that, The outer shell (5), rotating shaft (8), limiting ring I (6), limiting ring II (15) and end cap (16) are all made of non-magnetic materials; the bushing I (9), bushing II (14) and pole shoe (10) are all made of magnetic materials.

7. The magnetic liquid composite sealing device for centrifugal assisted heat dissipation according to claim 1, characterized in that, The bearing (7) is a rolling bearing or a sliding bearing, and there are two of them, which are respectively located on the left side of the bushing I (9) and the right side of the bushing II (14).

8. The magnetic liquid composite sealing device for centrifugal assisted heat dissipation according to claim 1, characterized in that, The two limiting rings I (6) are set on the inner side of the outer shell (5) to axially position the two sides of the pole shoe (10); the limiting ring II (15) is sleeved on the rotating shaft (8) by interference fit and rotates synchronously with the rotating shaft (8) to axially limit the bushing I (9), the magnet (13) and the bushing II (14).

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