An electro-permanent magnet magnetic liquid sealing device and a method for installing a magnetic liquid sealing spindle.

Abstract

This invention discloses an electro-permanent magnet magnetic liquid sealing device, characterized by comprising a shell, an excitation coil, an outer permanent magnet, a left pole shoe, an inner permanent magnet, a right pole shoe, magnetic liquid, and an end cap. This invention achieves flexible switching of the magnetic circuit within the sealing device by changing the magnetic pole direction of the electro-permanent magnet, thus solving problems such as unstable axial force and easy leakage of magnetic liquid during the spindle installation process of existing magnetic liquid sealing devices.

Description

Technical Field

[0001] This invention relates to the field of mechanical engineering sealing technology, and in particular to an electro-permanent magnet magnetic liquid sealing device and a method for installing a magnetic liquid sealing spindle. Background Technology

[0002] Magnetic fluid rotary shaft dynamic seals are a novel type of non-contact seal. Due to the fluidity and magnetic properties of the magnetic fluid itself, the magnetic circuit design in the magnetic fluid sealing device creates a "liquid O-ring" within the magnetic field gap. Based on the balance between non-uniform magnetic field force and pressure within the magnetic fluid, a stable seal can be achieved under certain pressures. However, during the installation of the magnetic fluid spindle, the permanent magnet's magnetic field exerts an axial attraction or repulsion on the conductive spindle, causing instability during installation and leading to potential leakage and uneven distribution of the magnetic fluid. To address these issues, the magnetic circuit in the magnetic fluid sealing device needs to be flexibly adjusted to ensure that the spindle installation process is unaffected by the magnetic field force. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, the purpose of this invention is to propose an electro-permanent magnet magnetic liquid sealing device and a magnetic liquid sealing spindle installation method. It changes the magnetic circuit design of existing magnetic liquid seals and achieves the switching between the inner and outer circulation magnetic circuits by changing the magnetic pole direction of the low coercivity permanent magnet, thus realizing the smooth installation of the sealing spindle. This device can solve the problems of unstable installation process of the magnetic liquid sealing device spindle and easy loss of magnetic liquid.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] An electro-permanent magnet magnetic liquid sealing device, characterized in that it includes a shell, an excitation coil, an outer permanent magnet, a left pole shoe, an inner permanent magnet, a right pole shoe, and an end cap;

[0007] The connections between the various parts constituting this sealing device are as follows:

[0008] Two sealing rings are installed on the left and right pole shoes, and the excitation coil is installed in the groove of the outer shell. The inner permanent magnet, the magnetic shielding ring, and the outer permanent magnet are concentrically fitted together radially from the inside to the outside to form the first mounting assembly. The left bearing, the left magnetic shielding washer, the left pole shoe, the first mounting assembly, the right pole shoe, the right magnetic shielding washer, and the right bearing are installed in sequence inside the outer shell to form the second mounting assembly. Then, the second mounting assembly is fixed to the end cover with bolts.

[0009] In addition, an electro-permanent magnet magnetic liquid sealing device according to the above embodiments of the present invention may also have the following additional technical features:

[0010] In one embodiment of the present invention, the inner permanent magnet adopts a ring structure, is axially magnetized, and is made of neodymium iron boron.

[0011] In one embodiment of the present invention, the external permanent magnet adopts a ring structure, is axially magnetized, and is made of AlNiCo.

[0012] A method for installing a magnetic fluid-sealed spindle involves energizing the excitation coil of the electro-permanent magnet magnetic fluid sealing device as described in claim 1. This magnetizes the outer permanent magnet, causing it to have a polarity opposite to that of the inner permanent magnet, forming an internal circulation magnetic circuit. Magnetic fluid is then injected into the root portion of the pole teeth. The electro-permanent magnet magnetic fluid sealing device is fitted onto the shaft, with the shaft and left and right bearings in a transition fit. The excitation coil is then energized, causing the magnetic pole direction of the outer permanent magnet to align with that of the inner permanent magnet, forming an external circulation magnetic circuit. Under the influence of a non-uniform magnetic field, the magnetic fluid enters the gap at the end of the pole teeth, completing the installation of the sealed spindle.

[0013] In one embodiment of the present invention, the magnetic fluid has low viscosity and magnetoviscosity and high saturation magnetization. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the magnetic liquid sealing structure of the present invention;

[0015] Figure 2 This is a schematic diagram of the internal circulation magnetic circuit of the present invention;

[0016] Figure 3 This is a schematic diagram of the external circulation magnetic circuit of the present invention;

[0017] Explanation of reference numerals in the attached figures:

[0018] 1-Outer shell, 2-Left bearing, 3-Left magnetic isolation washer, 4-Excitation coil, 5-Outer permanent magnet, 6-Sealing ring, 7-Right magnetic isolation washer, 8-Bolt, 9-Right bearing, 10-Left pole shoe, 11-Magnetic isolation ring, 12-Inner permanent magnet, 13-Right pole shoe, 14-Magnetic fluid, 15-End cap, 16-Shaft; Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings.

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, embodiments of the invention are described in detail below, providing further elaboration. It should be understood that the following embodiments are intended to explain the invention but are not intended to limit it.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] The following description, with reference to the accompanying drawings, describes a series-connected electro-permanent magnet magnetic liquid sealing device according to an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of the internal circulation magnetic circuit of the present invention.

[0024] The excitation coil 4 magnetizes the outer permanent magnet 5, causing the magnetic poles of the inner permanent magnet 12 and the outer permanent magnet 5 to be opposite. The magnetic lines of force originate from the N pole of the outer permanent magnet 5, pass through the right pole shoe 13 to the S pole of the inner permanent magnet 12, and then originate from the N pole of the inner permanent magnet 12, pass through the left pole shoe 10 to the S pole of the outer permanent magnet 5, forming an inner circulation magnetic circuit. At this time, the insertion shaft 16 does not affect the magnetic circuit distribution within the sealing device.

[0025] Figure 3 This is a schematic diagram of the internal circulation magnetic circuit of the present invention.

[0026] After the sealed spindle is installed, the excitation coil 4 changes the direction of the magnetic poles of the outer permanent magnet 5 through electrical pulses, aligning the outer permanent magnet 5 with the inner permanent magnet 12. Magnetic field lines originate from the N poles of the inner permanent magnet 12 and the outer permanent magnet 5, pass through the left pole shoe 10, the magnetic fluid 14, the shaft, and the right pole shoe 13, and return to the S poles of the inner permanent magnet 12 and the outer permanent magnet 5, forming an external circulating magnetic circuit distribution. At this time, the magnetic fluid 14 is evenly distributed under the pole tooth gap, achieving the designed pressure resistance performance.

Claims

1. An electro-permanent magnet magnetic liquid sealing device, characterized in that, It includes a housing (1), an excitation coil (4), an outer permanent magnet (5), a left pole shoe (10), an inner permanent magnet (12), a right pole shoe (13), and an end cap (15); The connections between the various parts constituting this sealing device are as follows: Two sealing rings (6) are installed on the left pole shoe (10) and the right pole shoe (13), and the excitation coil (4) is installed in the groove of the outer shell (1); the inner permanent magnet (12), the magnetic shielding ring (11), and the outer permanent magnet (5) are concentrically fitted together radially from the inside to the outside to form the first mounting assembly; the left bearing (2), the left magnetic shielding washer (3), the left pole shoe (10), the first mounting assembly, the right pole shoe (13), the right magnetic shielding washer (7), and the right bearing (9) are installed in sequence inside the outer shell (1) to form the second mounting assembly, and then the second mounting assembly is fixed to the end cover (15) with bolts (8).

2. The electro-permanent magnet magnetic liquid sealing device according to claim 1, characterized in that, The external permanent magnet (5) adopts a ring structure, is axially magnetized, and is made of neodymium iron boron.

3. The electro-permanent magnet magnetic liquid sealing device according to claim 1, characterized in that, The inner permanent magnet (12) adopts a ring structure, is axially magnetized, and is made of AlNiCo.

4. The electro-permanent magnet magnetic liquid sealing device according to claim 1, characterized in that, The internal permanent magnet (12) is not fully magnetized.

5. A method for installing a magnetic liquid-sealed spindle, wherein the excitation coil (4) of the electro-permanent magnet magnetic liquid sealing device of claim 1 is energized to magnetize the outer permanent magnet (5) and make its polarity opposite to that of the inner permanent magnet (12), forming an inner circulation magnetic circuit, and the magnetic liquid (14) is injected into the root of the pole teeth; the electro-permanent magnet magnetic liquid sealing device is fitted onto the shaft (16), the shaft (16) is transitionally fitted with the left bearing (2) and the right bearing (9), and then the excitation coil (4) is energized to make the magnetic pole direction of the outer permanent magnet (5) be converted to be consistent with the magnetic pole direction of the inner permanent magnet (12), forming an outer circulation magnetic circuit, and the magnetic liquid (14) enters the gap at the end of the pole teeth under the influence of the non-uniform magnetic field force, thus completing the installation of the sealed spindle.

6. According to claim 5, the magnetic fluid sealing spindle installation method has a low viscosity, a low magnetoviscosity effect, and a high saturation magnetization intensity.

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