Multi-layer magnetic fluid sealing device based on planet wheel speed reduction structure

Abstract

The invention relates to the technical field of mechanical sealing, in particular to a multi-layer magnetic fluid sealing device based on a planet wheel speed reduction structure, which comprises a controller, a motor, a sealing seat and a shaft sleeve, the inner side wall of the shaft sleeve is fixedly connected with a motor output shaft, bearings are fixedly connected to the sides, close to the sealing seat, of the top and the bottom of the shaft sleeve, and the sides, away from the shaft sleeve, of the bearings are fixedly connected with the sealing seat. Sealing assemblies are arranged between the bearings, and speed reduction assemblies are arranged on the tops of the bearings. The first planetary gear and the second planetary gear are applied to the device, and a four-layer four-point contact ball bearing structure is adopted, so that the problem that the advantages of a conventional magnetic fluid sealing device are difficult to play under the condition that the axial size is not large is solved.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical seals, and in particular to a multi-layer magnetic fluid sealing device based on a planetary gear reduction structure. Background Art

[0002] Magnetic fluid, also known as magnetic liquid or ferrofluid, is a colloidal material composed of two phases: solid and liquid. The solid phase mainly refers to magnetic solid nanoparticles, and the liquid phase refers to the liquid that can carry solid magnetic nanoparticles. Magnetic fluid has the fluidity, lubricity and sealing properties of liquid carriers, and the strong magnetism of solid nanoparticles. Magnetic fluid can show the characteristics of fluid fluidity on the one hand, and the magnetic action characteristics of magnetic materials on the other hand, so it is widely used in many fields, especially in the field of sealing, where magnetic fluid seals are playing an increasingly important role.

[0003] At present, conventional magnetic fluid sealing devices are difficult to exert their advantages when the axial size is not large, and thus cannot meet the harsh working conditions required by large-diameter centrifuges.

[0004] In summary, conventional magnetic fluid sealing devices are difficult to exert their advantages when the axial size is not large, and thus are difficult to meet the harsh working conditions required by large-diameter centrifuges. This has become a difficult problem that needs to be solved urgently in this field. Therefore, it is necessary to propose a multi-layer magnetic fluid sealing device based on a planetary gear reduction structure. Summary of the invention

[0005] To solve the above problems, the present invention provides a multi-layer magnetic fluid sealing device based on a planetary gear reduction structure. By applying a first planetary gear and a second planetary gear to the device and adopting a four-layer four-point contact ball bearing structure, the problem that conventional magnetic fluid sealing devices are difficult to exert their advantages when the axial size is not large is solved.

[0006] In order to achieve the above-mentioned purpose, the technical solution of the present invention is as follows: a multilayer magnetic fluid sealing device based on a planetary gear reduction structure, including a controller, a motor, an annular sealing seat and an annular sleeve, the motor is electrically connected to the controller, and the controller is used to control the start and stop of the motor.

[0007] The shaft sleeve is located on the inner side of the sealing seat, and the inner wall of the shaft sleeve is coaxially fixedly connected to the motor output shaft, and the top and bottom of the shaft sleeve are fixedly connected to the sealing seat, and the side of the bearing away from the shaft sleeve is fixedly connected to the sealing seat; a sealing assembly for magnetic fluid sealing is provided between the bearings, and a reduction assembly is provided on the top of the bearing; the reduction assembly includes a plurality of racks and a plurality of first planetary gears, and the first planetary gears and the racks are staggered between the shaft sleeve and the sealing seat, and the first planetary gears are meshed with the racks adjacent to them, and a plurality of second planetary gears are fixedly connected to the top of the rack located at the center between the shaft sleeve and the sealing seat, and the second planetary gears are meshed with the racks adjacent to them, and the shaft sleeve and the sealing seat are fixedly connected to the racks adjacent to them.

[0008] The technical principles of the above scheme are as follows:

[0009] The controller controls the motor to start, at which time the motor output shaft rotates, and the motor output shaft drives the shaft sleeve to rotate together, and the shaft sleeve drives the adjacent and fixedly connected rack to rotate, and then the rack drives the first planetary gear and the second planetary gear meshing with it to make a circular motion around the motor output shaft.

[0010] Since the plurality of first planetary gears and the plurality of racks are staggered between the shaft sleeve and the sealing seat, and the plurality of second planetary gears are fixedly connected to the top of the rack at the center position between the shaft sleeve and the sealing seat, when the first planetary gears and the second planetary gears make circular motions around the output shaft of the motor, the racks meshing with the first planetary gears and the second planetary gears are respectively driven to rotate by the first planetary gears and the second planetary gears.

[0011] When the shaft sleeve rotates, the shaft sleeve drives the annular rack fixedly connected thereto to rotate, and then drives the first planetary gear meshing with the annular rack to rotate. During the rotation process, the first planetary gear decelerates the rack driven by the first planetary gear, thereby decelerating the other first planetary gears driven by the decelerated rack, and realizing the step-by-step reduction of the rotation speed of the first planetary gear and the rack from the motor output shaft to the sealing seat, thereby realizing the multi-layer magnetic fluid sealing device to cope with high-speed working conditions.

[0012] While the second planetary gear is driven to rotate by the rack, since the second planetary gear is fixedly connected to the rack at the center position between the sleeve and the sealing seat, the second planetary gear will decelerate the rack fixedly connected to it during rotation, thereby further enhancing the deceleration effect of the deceleration assembly.

[0013] At the same time, when the motor output shaft rotates, the sleeve will rotate with the motor output shaft, and the sealing component will rotate with the sleeve. At this time, the sealing component operates to seal the multi-layer magnetic fluid sealing device.

[0014] The above scheme has the following beneficial effects:

[0015] 1. This solution optimizes the power transmission path and reduces energy loss by applying the first planetary gear and the second planetary gear to the device, thereby improving the overall transmission efficiency. At the same time, the multi-layer magnetic fluid sealing device can also play its advantages even when the axial size is not large.

[0016] 2. This solution uses multiple first planetary gears at the same time, and combined with the design of the second planetary gear, it can achieve more complex transmission control and speed regulation by adjusting the transmission ratio and arrangement of different first planetary gears and second planetary gears.

[0017] 3. In this solution, the sealing assembly adopts a magnetic fluid seal design, which can effectively reduce the jitter and shaking of the multi-layer magnetic fluid sealing device when rotating at high speed, thereby improving the operating stability and safety of the multi-layer magnetic fluid sealing device. This helps to reduce equipment failures and downtime caused by vibration and extend the service life of the equipment.

[0018] Furthermore, the sealing assembly includes a plurality of sleeves and a plurality of pole shoe assemblies spaced apart between the shaft sleeve and the sealing seat. The pole shoe assembly includes a pole shoe, each of which is fixedly connected to a permanent magnet. The inner side walls of the pole shoes are fixedly connected to a pole shoe shaft, both ends of the pole shoe shaft are rotatably matched with adjacent bearings, and the sealing seat and the shaft sleeve are slidably matched with adjacent pole shoes.

[0019] Beneficial effects: The multiple magnetic fluid sealing barriers formed by the interval arrangement of sleeves and pole shoe assemblies can more effectively reduce medium leakage, improve the reliability and safety of sealing, and the multiple magnetic fluid sealing structures can well cope with the working conditions of various media. At the same time, the design of multiple pole shoe assemblies helps to disperse the load between the sleeve and the sealing seat, reduce local stress concentration, and improve the stability and durability of the overall structure.

[0020] Furthermore, a plurality of pole teeth are fixedly connected to the inner side wall of the pole shoe, grooves are provided between adjacent pole teeth, and the grooves are filled with magnetic fluid.

[0021] Beneficial effects: The presence of pole teeth can enhance the magnetic induction intensity in the sealing gap, and the groove design between adjacent pole teeth helps to optimize the distribution of magnetic fluid in the sealing gap. The groove can guide the magnetic fluid to form a more stable flow pattern between the pole teeth, reducing the risk of magnetic fluid leakage.

[0022] Furthermore, a plurality of inlet holes for the magnetic fluid to enter are opened at the top of the pole shoe.

[0023] Beneficial effects: The design of the entry hole helps to ensure that the magnetic fluid fully fills the sealing gap, thereby improving the strength and reliability of the seal. At the same time, during use, when the magnetic fluid is reduced due to evaporation, leakage, etc., the magnetic fluid can be conveniently replenished through the entry hole to maintain the normal operation of the sealing device.

[0024] Furthermore, the inlet holes are all connected to electric one-way valves, and the electric one-way valves are all electrically connected to a controller, and the controller is used to control the opening and closing of the electric one-way valves.

[0025] Beneficial effects: Through the precise control of the electric one-way valve by the controller, the flow of magnetic fluid can be dynamically adjusted under different working conditions. This helps to ensure that the magnetic fluid can quickly enter the sealing gap when needed to form a stable sealing layer, and at the same time, the flow can be cut off in time when it is not needed, reducing the waste and leakage of magnetic fluid.

[0026] Furthermore, a top cover is detachably connected to the top of the sealing seat, and the top cover is slidably matched with the shaft sleeve.

[0027] Beneficial effects: The sliding fit mechanism between the top cover and the sleeve allows the top cover to slide on the sleeve surface without causing excessive friction and wear, thereby ensuring the sealing effect of the multi-layer magnetic fluid sealing device. At the same time, the presence of the top cover can effectively prevent external impurities and contaminants from entering the interior of the sealing component, thereby protecting the sealing component from damage and extending its service life.

[0028] Furthermore, a plurality of fixing holes are formed on the sealing seat.

[0029] Beneficial effect: The sealing seat is tightly connected to other components through the fixing hole, which helps to reduce the risk of medium leakage caused by loose or falling parts. This tight connection relationship helps to maintain the sealing performance of the sealing assembly, prevent medium leakage and protect the equipment from damage.

[0030] Further, the first planetary gear and the second planetary gear are both made of carbon steel.

[0031] Beneficial effect: Carbon steel is not only high in strength but also has a certain toughness, which enables the first planetary gear and the second planetary gear to absorb part of the energy when impacted or vibrated, thereby reducing the risk of overall damage to the device.

[0032] Furthermore, the bearings are all four-point contact ball bearings.

[0033] Beneficial effects: The internal structure of the four-point contact ball bearing has high rigidity and can maintain low deformation under high load, which helps to reduce vibration and noise of the bearing during operation and improve the overall operation quality of the equipment.

[0034] Furthermore, the racks are all ring-shaped.

[0035] Beneficial effects: Due to its unique annular design, the annular rack can provide a longer transmission path in a limited space, thereby improving space utilization, and the contact between the annular rack and the first planetary gear and the second planetary gear is continuous, which helps to reduce impact and vibration during the transmission process and make the transmission smoother.

[0036] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is an axonometric schematic diagram of a multilayer magnetic fluid sealing device based on a planetary gear reduction structure in an embodiment of the present invention.

[0038] Figure 2 It is a top view and cross-sectional schematic diagram of a multi-layer magnetic fluid sealing device based on a planetary gear reduction structure in an embodiment of the present invention.

[0039] Figure 3 It is a side cross-sectional schematic diagram of a multi-layer magnetic fluid sealing device based on a planetary gear reduction structure in an embodiment of the present invention.

[0040] Figure 4 It is a front cross-sectional view of a pole shoe assembly in an embodiment of the present invention.

[0041] The figure marks in the drawings of the specification include: 1, sealing seat; 2, sleeve; 3, bearing; 4, sleeve; 5, pole shoe; 6, first planetary gear; 601, second planetary gear; 7, rack; 8, top cover; 9, fixing hole; 10, permanent magnet; 11, pole shoe shaft; 12, pole tooth. DETAILED DESCRIPTION

[0042] The following is further described in detail through specific implementation methods:

[0043] Embodiment 1:

[0044] As attached Figure 1 , Figure 2 and Figure 3 As shown: a multi-layer magnetic fluid sealing device based on a planetary gear reduction structure, including a controller, a motor, a sealing seat 1 and a ring-shaped sleeve 2, the motor is electrically connected to the controller, and the controller is used to control the start and stop of the motor.

[0045] The shaft sleeve 2 is located inside the sealing seat 1, and the inner wall of the shaft sleeve 2 is coaxially fixedly sleeved with the motor output shaft. Figure 3As shown, bearings 3 are welded to the top and bottom of the sleeve 2, and the side of the bearing 3 away from the sleeve 2 is welded to the sealing seat 1. In this embodiment, four-point contact ball bearings are used for the bearings 3; sealing components for magnetic fluid sealing are provided between the bearings 3, and a reduction component is provided on the top of the bearing 3.

[0046] The sealing assembly includes a plurality of sleeves 4 and a plurality of pole shoe assemblies which are spaced apart between the shaft sleeve 2 and the sealing seat 1. The pole shoe assemblies include pole shoes 5, each of which is integrally formed with a permanent magnet 10, each of which is integrally formed with a pole shoe shaft 11 on the inner wall of the pole shoe 5, each of which is integrally formed with a plurality of pole teeth 12 on the inner wall of the pole shoe 5, each of which is integrally formed with grooves between adjacent pole teeth 12, each of which is filled with magnetic fluid.

[0047] Both ends of the pole shoe shaft 11 are rotationally matched with the bearings 3 adjacent thereto, and both the sealing seat 1 and the shaft sleeve 2 are slidingly matched with the pole shoe 5 adjacent thereto.

[0048] The reduction assembly includes a plurality of racks 7 and a plurality of first planetary gears 6. The racks 7 are all annular in shape. The first planetary gears 6 and the racks 7 are staggered between the shaft sleeve 2 and the sealing seat 1. The first planetary gears 6 are meshed with the racks 7 adjacent thereto. The top of the rack 7 located at the center position between the shaft sleeve 2 and the sealing seat 1 is bolted and fixed with a plurality of second planetary gears 601. The first planetary gears 6 and the second planetary gears 601 are both made of carbon steel. The second planetary gears 601 are meshed with the racks 7 adjacent thereto. The shaft sleeve 2 and the sealing seat 1 are welded to the racks 7 adjacent thereto.

[0049] The specific implementation process is as follows: In this embodiment, the reduction assembly uses the NGW72 planetary reducer. The operator operates the controller to start the motor. At this time, the output shaft of the motor rotates, driving the shaft sleeve 2 coaxially fixedly sleeved therewith to rotate together. When the shaft sleeve 2 rotates, the shaft sleeve 2 drives the annular rack 7 welded thereto to rotate, thereby driving the first planetary gear 6 and the second planetary gear 601 meshed with the annular rack 7 to rotate. During the rotation process, the first planetary gear 6 decelerates the rack 7 driven by the first planetary gear 6, thereby decelerating the other first planetary gears 6 driven by the decelerated rack 7, realizing the step-by-step reduction of the rotation speed of the first planetary gear 6 and the rack 7 from the motor output shaft to the sealing seat 1, thereby realizing the response of the multi-layer magnetic fluid sealing device to high-speed working conditions.

[0050] At the same time, when the second planetary gear 601 is driven by the rack 7, it will decelerate the rack 7 that is bolted to it, thereby further enhancing the deceleration effect of the deceleration assembly.

[0051] When the motor output shaft rotates, since the sleeve 2 will rotate together with the motor output shaft, the pole shoe 5 that is slidably matched with the sleeve 2 will also rotate with the rotation of the sleeve 2, thereby driving the pole shoe shaft 11 that is integrally formed with the pole shoe 2 to rotate. When the pole shoe 5 rotates, the magnetic fluid inside the pole shoe 5 is adsorbed on the pole teeth 12 and the groove surface to achieve a sealing effect. At the same time, since the pole shoe shaft 11 is rotated in coordination with the bearing 3, when the motor output shaft drives the sleeve 2 to rotate, the bearing 3 welded to the sleeve 2 will also rotate with the sleeve 2, thereby further driving the pole shoe 5 to rotate, further enhancing the sealing effect of the magnetic fluid inside the pole shoe 5. In this embodiment, the structure of the bearing 3 adopts a four-layer four-point contact ball bearing.

[0052] Embodiment 2:

[0053] As attached Figure 4 As shown, the difference from Example 1 is that a plurality of inlet holes for magnetic fluid to enter are opened at the top of the pole shoe 5, and the inlet holes are connected to electric one-way valves, and the electric one-way valves are electrically connected to the controller, and the controller is used to control the opening and closing of the electric one-way valves.

[0054] The specific implementation process is as follows: when the magnetic fluid in the pole shoe 5 is insufficient, the operator operates the controller to open the electric one-way valve, and then magnetic fluid can be added to the pole shoe 5 through the electric one-way valve to ensure the normal operation of the multi-layer magnetic fluid sealing device.

[0055] When the operator operates the controller to control the operation of the motor, the operator first operates the controller to close the electric one-way valve to reduce the damage to the multi-layer magnetic fluid sealing device caused by the backflow of the magnetic fluid and ensure that the magnetic fluid flows along a preset path, thereby improving the sealing performance of the multi-layer magnetic fluid sealing device.

[0056] Embodiment 3:

[0057] As attached Figure 1 As shown, the difference from Example 2 is that the top of the sealing seat 1 is detachably connected to a top cover 8 by bolts, and the top cover 8 is slidably matched with the shaft sleeve 2.

[0058] The specific implementation process is as follows: when the motor output shaft rotates, the motor output shaft drives the sleeve 2 to rotate. At this time, since the top cover 8 is detachably connected to the top bolt of the sealing seat 1, the top cover 8 is bolted to the top of the sealing seat 1 and slides with the sleeve 2. This connection method reduces the friction between the top cover 8 and the sleeve 2, thereby reducing the wear of the top cover 8 and the sleeve 2. At the same time, since the top cover 8 is located above the sealing seat 1 and the sleeve 2, it can effectively reduce the entry of impurities into the multi-layer magnetic fluid sealing device, thereby increasing the service life of the multi-layer magnetic fluid sealing device.

[0059] Embodiment 4:

[0060] As attached Figure 1 , Figure 2 and Figure 3 As shown, the difference from embodiment 3 is that a plurality of fixing holes 9 are provided on the sealing seat 1 .

[0061] The specific implementation process is as follows: the design of the fixing hole 9 enables the operator to conveniently install or disassemble the multi-layer magnetic fluid sealing device through bolts when the multi-layer magnetic fluid sealing device needs to be installed or disassembled. The sealing seat 1 and other components are firmly installed through the fixing hole 9, which can reduce the risk of medium leakage caused by loose or falling components, maintain the sealing performance of the sealing assembly, and reduce the risk of medium leakage and equipment damage.

[0062] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A multi-layer magnetic fluid sealing device based on a planetary gear reduction structure, characterized in that: It comprises a controller, a motor, a sealing seat (1) and a shaft sleeve (2) of an annular design, wherein the motor is electrically connected to the controller, and the controller is used to control the start and stop of the motor; The shaft sleeve (2) is located inside the sealing seat (1), the inner wall of the shaft sleeve (2) is coaxially fixedly connected to the motor output shaft, the top and bottom of the shaft sleeve (2) are fixedly connected to the bearing (3), and the side of the bearing (3) away from the shaft sleeve (2) is fixedly connected to the sealing seat (1); a sealing component for magnetic fluid sealing is provided between the bearings (3), and a reduction component is provided on the top of the bearing (3); the reduction component comprises a plurality of racks (7) and a plurality of first planetary gears (6), the first planetary gears (6) and the racks (7) are staggeredly arranged between the shaft sleeve (2) and the sealing seat (1), the first planetary gears (6) are meshed with the racks (7) adjacent thereto, a plurality of second planetary gears (601) are fixedly connected to the top of the rack (7) located at the center position between the shaft sleeve (2) and the sealing seat (1), the second planetary gears (601) are meshed with the racks (7) adjacent thereto, and the shaft sleeve (2) and the sealing seat (1) are fixedly connected to the racks (7) adjacent thereto.

2. The multi-layer magnetic fluid sealing device based on the planetary gear reduction structure according to claim 1 is characterized in that: The sealing assembly comprises a plurality of sleeves (4) and a plurality of pole shoe assemblies which are arranged at intervals between a shaft sleeve (2) and a sealing seat (1). The pole shoe assembly comprises a pole shoe (5). A permanent magnet (10) is fixedly connected to each pole shoe (5). The inner side wall of the pole shoe (5) is fixedly connected to a pole shoe shaft (11). Both ends of the pole shoe shaft (11) are rotatably matched with a bearing (3) adjacent thereto. The sealing seat (1) and the shaft sleeve (2) are slidably matched with the pole shoe (5) adjacent thereto.

3. The multi-layer magnetic fluid sealing device based on the planetary gear reduction structure according to claim 2 is characterized in that: A plurality of pole teeth (12) are fixedly connected to the inner side wall of the pole shoe (5), and grooves are provided between adjacent pole teeth (12), and the grooves are filled with magnetic fluid.

4. The multi-layer magnetic fluid sealing device based on the planetary gear reduction structure according to claim 3 is characterized in that: The top of the pole shoe (5) is provided with a plurality of inlet holes for the magnetic fluid to enter.

5. The multi-layer magnetic fluid sealing device based on the planetary gear reduction structure according to claim 4 is characterized in that: The inlet holes are all connected to electric one-way valves, and the electric one-way valves are all electrically connected to a controller, and the controller is used to control the opening and closing of the electric one-way valves.

6. The multi-layer magnetic fluid sealing device based on the planetary gear reduction structure according to claim 5 is characterized in that: A top cover (8) is detachably connected to the top of the sealing seat (1), and the top cover (8) is slidably matched with the shaft sleeve (2).

7. The multi-layer magnetic fluid sealing device based on the planetary gear reduction structure according to claim 6 is characterized in that: The sealing seat (1) is provided with a plurality of fixing holes (9).

8. The multi-layer magnetic fluid sealing device based on the planetary gear reduction structure according to claim 7 is characterized in that: The first planetary gear (6) and the second planetary gear (601) are both made of carbon steel.

9. The multi-layer magnetic fluid sealing device based on the planetary gear reduction structure according to claim 8, characterized in that: The bearings (3) are all four-point contact ball bearings.

10. The multi-layer magnetic fluid sealing device based on the planetary gear reduction structure according to claim 9, characterized in that: The racks (7) are all in the shape of a ring.

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