Magnetic fluid seal using stator winding pole piece

Abstract

The application relates to a magnetic fluid seal using a stator winding type pole shoe, comprising a shell, a stator type pole shoe ring, winding coils and a rotating shaft. The application applies a motor stator winding structure to a magnetic liquid seal, adjusts the size of winding coil current, realizes the adjustment of the size of the magnetic field of the sealing gap, and solves the problems of difficult magnetization, difficult processing, easy demagnetization and uncontrollable magnetic field of the commonly used permanent magnet of the magnetic liquid seal.

Description

Technical Field

[0001] This invention belongs to the field of mechanical engineering sealing, and specifically relates to a magnetohydrodynamic seal using stator winding pole shoes. Background Technology

[0002] Magnetofluid sealing utilizes the magnetic force generated by a permanent magnet within the sealing gap to firmly fix the magnetofluid within the gap, resisting the pressure difference on both sides, thereby achieving a sealing effect.

[0003] The permanent magnets commonly used in magnetic fluid seals are generally sintered neodymium iron boron (NdFeB) materials, which are difficult to process and are brittle and hard. Once the structure is determined, the magnetic field it generates cannot be controlled, and it suffers from severe demagnetization in extreme environments, affecting pressure resistance and seal stability. Furthermore, while the columnar structure of magnetic particles at the sealing gap does improve pressure resistance under static and steady-state magnetic field conditions—explaining how the pressure resistance of magnetic fluid seals increases over time under static sealing—it also results in a significant increase in starting torque under dynamic sealing conditions. This severely hinders the starting of the sealing spindle, and once forced to start, the increased pressure resistance due to the columnar structure of the magnetic fluid particles disappears. Therefore, in dynamic sealing applications, the presence of the columnar structure of magnetic particles presents disadvantages such as high starting torque and inaccurate pressure resistance, making it largely meaningless and should be avoided. Summary of the Invention

[0004] The purpose of this invention is to provide a magnetic fluid sealing device using stator winding pole shoes. By applying the stator winding structure of a motor to magnetic fluid sealing, the magnitude of the magnetic field in the sealing gap can be adjusted by regulating the current of the winding coil. This solves the problems of large starting torque, inaccurate pressure resistance, and difficulty in magnetizing, processing, demagnetizing, and uncontrollable magnetic field of permanent magnets in magnetic fluid sealing.

[0005] This patent presents finite element simulations of numerous magnetic fluid sealing examples, analyzes the simulation results, and proposes a reasonable design scheme for magnetic fluid sealing using stator winding pole shoes.

[0006] The technical solution of the present invention is as follows: A magnetohydrodynamic seal using stator winding pole shoes includes a shaft, a magnetic ring, a stator pole shoe ring, a non-magnetic ring, a winding coil, and a housing; characterized in that: the magnetic ring and the stator pole shoe ring are disposed on the inner wall of the housing, a gap is left between the inner circular surface of the stator pole shoe ring and the outer circular surface of the shaft, and the non-magnetic ring is disposed between the two stator pole shoe rings; the outer circular surface of the shaft is provided with pole teeth, the pole teeth being radially directed towards the inner surface of the stator pole shoe ring. The outer circular surface extends with a gap, which is filled with magnetic fluid for sealing. To ensure that the gap between the outer circular surface of the shaft and the inner circular surface of the stator pole shoe ring forms a uniform magnetic field along the circumference, the stator core has several pole phase slots inside. The distance between the smallest diameter of the pole phase slot and the outer circular surface of the shaft is 0.05 to 3 mm. The coil is embedded in the pole phase slot using a slotted wire embedding structure, with 12 to 36 slots. After the winding coil wiring is completed, the pole phase slots of the stator pole shoe ring are installed together with the magnetic ring.

[0007] The magnetohydrodynamic seal using stator winding type pole shoes is characterized in that: the number of pole teeth on the outer circular surface of the shaft is 2 to 20.

[0008] The magnetic fluid seal using stator winding pole shoes is characterized in that the gap between the outer circular surface of the pole teeth of the shaft and the inner circular surface of the stator pole shoe ring (3) is 0.05 to 3 mm.

[0009] The magnetic fluid seal using stator winding pole shoes is characterized in that: the winding coil is copper wire covered with enamel, powered by a DC power supply, and the windings in different pole shoe rings are supplied with DC current in opposite directions. The magnetic field generated at the center of the winding coil enters the center of another winding coil through the magnetic pole shoe and shaft to form a magnetic circuit.

[0010] The magnetohydrodynamic seal using stator winding pole shoes is characterized in that: the total number of pole phase slots per phase of the stator core of the stator pole shoe ring is even, and a sealing ring groove is provided on the outer circumferential surface of the stator pole shoe ring. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of a magnetohydrodynamic seal using stator winding pole shoes proposed in this invention; Figure 2 This is a structural distribution diagram of the radial cross-section polar phase groove of the present invention; Figure 3 This is a diagram showing the magnetic induction intensity distribution in the sealed gap. Figure 4 Magnetic induction intensity curve of the sealing gap. The serial numbers and their corresponding names in the figure are as follows: 1-shaft, 2-magnetic ring, 3-stator pole shoe ring, 4-non-magnetic ring, 5-winding coil, 6-sealing ring groove, 7-outer shell, 8-pole phase groove. Detailed Implementation

[0012] The invention will now be further described with reference to the accompanying drawings.

[0013] The technical solution of the present invention is as follows: A magnetohydrodynamic seal using stator winding pole shoes includes a shaft, a magnetic ring, a stator pole shoe ring, a non-magnetic ring, a winding coil, and a housing; characterized in that: the magnetic ring and the stator pole shoe ring are disposed on the inner wall of the housing, a gap is left between the inner circular surface of the stator pole shoe ring and the outer circular surface of the shaft, and the non-magnetic ring is disposed between the two stator pole shoe rings; the outer circular surface of the shaft is provided with pole teeth, the pole teeth being radially directed towards the inner circle of the stator pole shoe ring. The outer surface of the shaft extends outwards, leaving a gap filled with a magnetic fluid for sealing. To ensure a uniform circumferential magnetic field between the outer surface of the shaft and the inner surface of the stator pole shoe ring, the stator core contains several pole phase slots. The minimum diameter of each pole phase slot is 0.05–3 mm from the outer surface of the shaft. The coils are embedded in the pole phase slots using a slotted wire embedding structure, with 12–36 slots. After the winding coil wiring is completed, the pole phase slots of the stator pole shoe ring are installed together with the magnetic ring. Figure 1 , Figure 2 As shown.

[0014] The magnetohydrodynamic seal using stator winding type pole shoes is characterized in that: the number of pole teeth on the outer circular surface of the shaft is 2 to 20.

[0015] The magnetic fluid seal using stator winding pole shoes is characterized in that the gap between the outer circular surface of the pole teeth of the shaft and the inner circular surface of the stator pole shoe ring (3) is 0.05 to 3 mm.

[0016] The magnetic fluid seal using stator winding pole shoes is characterized in that: the winding coil is copper wire covered with enamel, powered by a DC power supply, and the windings in different pole shoe rings are supplied with DC current in opposite directions. The magnetic field generated at the center of the winding coil enters the center of another winding coil through the magnetic pole shoe and shaft to form a magnetic circuit.

[0017] The magnetohydrodynamic seal using stator winding pole shoes is characterized in that: the total number of pole phase slots per phase of the stator core of the stator pole shoe ring is even, and a sealing ring groove is provided on the outer circumferential surface of the stator pole shoe ring.

[0018] like Figure 3 , 4 As shown, the magnetic fluid seal using stator winding pole shoes can generate a certain magnetic field gradient in the sealing gap, enabling the magnetic fluid seal to have corresponding pressure resistance.

Claims

1. A magnetohydrodynamic seal using stator winding pole shoes, comprising a shaft (1), a magnetic ring (2), a stator pole shoe ring (3), a non-magnetic ring (4), a winding coil (5), and a housing (7); characterized in that: The magnetic ring (2) and stator pole shoe ring (3) are located on the inner wall of the outer shell (7). A gap is left between the inner circular surface of the stator pole shoe ring (3) and the outer circular surface of the shaft (1). The non-magnetic ring (4) is located between the two stator pole shoe rings (3). The outer circular surface of the shaft (1) is provided with pole teeth. The pole teeth extend radially toward the inner circular surface of the stator pole shoe ring (3) and are left with a gap. The gap is filled with magnetic fluid for sealing. In order to make the outer circular surface of the shaft (1) and the stator pole shoe ring (3) fit together, the magnetic ring (4) is positioned in a certain way. The gap between the inner circular surfaces of the stator pole shoe ring (3) forms a uniform magnetic field along the circumference. The stator core of the stator pole shoe ring (3) has several pole phase slots (8) along the axial direction. The distance between the smallest diameter of the pole phase slot (8) and the outer circular surface of the shaft (1) is 0.05~3mm. The coil is embedded in the pole phase slot using a slotted wire embedding structure. The number of inner slots is 12-36. After the winding coil wiring is completed, the pole phase slot (8) of the stator pole shoe ring (3) is installed together with the magnetic ring (2).

2. A magnetohydrodynamic seal using stator winding pole shoes as described in claim 1, characterized in that: The number of pole teeth on the outer circular surface of the shaft (1) is 2 to 20.

3. A magnetohydrodynamic seal using stator winding pole shoes as described in claim 1, characterized in that: The gap between the outer circular surface of the pole teeth of the shaft (1) and the inner circular surface of the stator pole shoe ring (3) is 0.05~3mm.

4. A magnetohydrodynamic seal using stator winding pole shoes as described in claim 1, characterized in that: The winding coil (5) is a copper wire covered with enamel and powered by a DC power supply. The windings in different pole shoe rings are powered by DC current in opposite directions. The magnetic field generated at the center of the winding coil enters the iron core of another winding coil through the iron core and shaft of the stator pole shoe ring to form a magnetic circuit.

5. A magnetohydrodynamic seal using stator winding pole shoes as described in claim 1, characterized in that: The total number of pole slots for each phase of the stator core of the stator type pole shoe ring (3) is even, and a sealing ring groove (6) is provided on the outer circular surface of the stator type pole shoe ring (3).

Images