CN-121977075-A - Self-adaptive magnetic pole extension type magnetic fluid sealing device and magnetic fluid sealing method

CN121977075ACN 121977075 ACN121977075 ACN 121977075ACN-121977075-A

Abstract

The invention discloses a self-adaptive magnetic pole extension type magnetic fluid sealing device and a magnetic fluid sealing method, wherein the self-adaptive magnetic pole extension type magnetic fluid sealing device comprises magnetic poles, permanent magnets, magnetic rotating shafts, magnetic fluid and flexible magnetic rubber; the flexible magnetic rubber wraps the periphery of the magnetic rotating shaft and is filled with Ni particles, the Ni particles are directionally adsorbed at the pole teeth of the magnetic poles under the action of a magnetic field to form flexible extending magnetic poles, the magnetic poles are effectively extended to the vicinity of the surface of the rotating shaft, the magnetic fluid is filled with sealing gaps under the directional constraint to form a dynamic sealing film, and the flexible magnetic constraint sealing with high bearing and low abrasion is realized. According to the invention, by constructing a three-dimensional material system of 'permanent magnet-flexible rubber matrix-magnetic fluid', the flexible extension magnetic pole is formed by utilizing Ni particles, so that the self-adaptive regulation and control of the sealing gap are realized, the contradiction that the bearing capacity is suddenly reduced when the sealing gap is increased in the traditional magnetic fluid sealing technology is effectively solved, and the sealing reliability is remarkably improved.

Inventors

LI ZHENGGUI
LI ZHENYU
FENG XIN
HUANG YICHAO
CHEN QINGYU

Assignees

西华大学
青海理工学院

Dates

Publication Date: 20260505
Application Date: 20260401

Claims (6)

1. An adaptive pole extension type magnetic fluid sealing device, comprising: the magnetic pole (1), the magnetic pole (1) has high magnetic permeability, saturation, magnetization intensity and low coercive force, and is used for constructing a magnetic field loop; The permanent magnet (6) is made of N38H neodymium iron boron material, and is used as a magnetic field source to provide a stable magnetic field; the magnetic rotating shaft (3), the magnetic rotating shaft (3) penetrates through the magnetic pole (1), and a sealing gap is formed between the magnetic rotating shaft (3) and the magnetic pole (1); The magnetic fluid (4) is filled in the sealing gap, and the magnetic fluid (4) consists of nano Fe 3 O 4 magnetic particles, a base carrier liquid and a surfactant; The flexible magnetic rubber (5), the flexible magnetic rubber (5) is wrapped in the magnetic fluid (4), the flexible magnetic rubber (5) comprises a flexible elastic matrix and Ni particles (2) dispersed in the flexible elastic matrix, the Ni particles (2) are directionally adsorbed at the pole teeth of the magnetic pole (1) under the action of the magnetic field of the permanent magnet (6) and extend the pole teeth to form flexible extending magnetic poles, the magnetic fluid (4) is directionally driven to the sealing gap under the action of the Ni particles (2), and the micro pores of the sealing gap are filled with nano Fe 3 O 4 magnetic particles to form a magnetic liquid sealing film; The flexible magnetic rubber (5) is in flexible contact with the magnetic rotating shaft (3), the flexible extending magnetic poles formed by the Ni particles (2) effectively extend the magnetic poles to the vicinity of the surface of the magnetic rotating shaft (3), and the magnetic fluid (4) fills the sealing gap under the directional constraint of the flexible extending magnetic poles to form dynamic sealing.
2. The adaptive pole extension type magnetic fluid sealing device according to claim 1, wherein the flexible elastic matrix is a silicone rubber matrix or a fluororubber matrix.
3. The adaptive pole extension type magnetic fluid sealing device according to claim 2, wherein the base carrier liquid of the magnetic fluid (4) is mineral oil or synthetic ester, and the surfactant is combined to maintain the dispersion stability of the nano-scale Fe 3 O 4 magnetic particles.
4. The adaptive pole extension type magnetic fluid sealing device according to claim 2, wherein the Ni particles (2) have high specific saturation magnetization, temperature stability and corrosion resistance, and are stable against corrosion of corrosive media in a sealed environment in response to the magnetic field of the permanent magnet (4) in a wide temperature range.
5. The adaptive pole extension type magnetic fluid sealing device according to claim 2, wherein the flexible magnetic rubber (5) has elastic deformation capability for adaptively compensating assembly deviation of a sealing surface and micro vibration in operation, and maintaining a dynamically stable sealing film structure.
6. A method of magnetic fluid sealing comprising sealing with an adaptive pole extension magnetic fluid sealing device according to any one of claims 1 to 5, comprising: s1, establishing a stable magnetic field environment through a permanent magnet (6); s2, utilizing the magnetic field gradient effect of the permanent magnet (6) to directionally adsorb Ni particles (2) in the flexible magnetic rubber (5) to the pole teeth of the magnetic pole (1) to form flexible extension magnetic poles; s3, under the action of the Ni particles (2), the magnetic fluid (4) is directionally driven to a sealing gap; S4, filling microscopic holes of the sealing gap through nano-scale Fe 3 O 4 magnetic particles to form a magnetic liquid sealing film, and blocking a medium leakage channel; s5, the runout and micro-vibration of the magnetic rotating shaft (3) are adaptively compensated through the elastic deformation of the flexible magnetic rubber (5), the flexible magnetic rubber (5) and the magnetic rotating shaft (3) form flexible contact, and the magnetic fluid (4) fills a sealing gap under the directional constraint of the flexible extending magnetic pole to form dynamic sealing.

Description

Self-adaptive magnetic pole extension type magnetic fluid sealing device and magnetic fluid sealing method Technical Field The invention relates to the technical field of magnetic fluid sealing, in particular to a self-adaptive magnetic pole extension type magnetic fluid sealing device and a magnetic fluid sealing method. Background The magnetic fluid sealing technology is used as an advanced non-contact sealing mode, forms a controllable liquid sealing film in a sealing gap by utilizing the magnetic response characteristic of magnetic liquid, has the remarkable advantages of zero leakage, low friction loss, high reliability, long service life and the like, and is widely applied to the industrial fields of vacuum equipment, liquid-gas medium sealing equipment, fluid pumps, sealing valves and the like, and becomes a key power transmission sealing support technology in a modern industrial system. However, existing magnetic fluid sealing techniques have many inherent limitations in practical engineering applications. Firstly, the working temperature range of the magnetic fluid is usually limited to a medium-low temperature environment ranging from minus 200 ℃ to 100 ℃, the volatilization of the magnetic fluid carrier liquid and the aggregation of magnetic particles are caused by the overhigh temperature, meanwhile, the demagnetization of the permanent magnet is induced, so that the sealing effect is thoroughly destroyed, secondly, a sealed medium must have good chemical inertness and be mutually insoluble with the magnetic fluid carrier liquid, once the interface is fused or chemically reacted, the instability of a sealing film is induced, so that the sealing performance is rapidly reduced, furthermore, the magnetic fluid must have low vapor pressure characteristic, the permanent magnet must have high coercive force and high Curie temperature, the material selection is strictly limited, and the complexity and the cost of the system design are increased. More importantly, the conventional magnetic fluid sealing technology faces the fundamental contradiction of the design of a sealing gap. On one hand, the bearing capacity of the magnetic fluid seal is closely related to the sealing gap, the sealing pressure is in direct proportion to the magnetic field intensity at the sealing gap according to the magnetic fluid statics theory, the magnetic field intensity is obviously attenuated due to the increase of the gap, so that the bearing capacity is sharply reduced, particularly when the gap is larger than 0.25mm, the sealing performance is difficult to meet the industrial high-pressure working condition requirement, on the other hand, the traditional structure is forced to adopt a tiny sealing gap (usually smaller than 0.15 mm) to realize enough bearing capacity, not only are extremely severe requirements on the machining precision of parts and the assembly process brought about, but also serious reliability problems are exposed in actual operation, namely, the radial runout and vibration of the rotating shaft inevitably exist in the high-speed rotation process, the direct contact friction between a rigid magnetic pole and the rotating shaft is extremely easy to occur, serious abrasion and abnormal heating of the magnetic pole surface are caused, the magnetic fluid volatilization, the permanent magnet demagnetization and other linkage failures are further caused, and finally the sealing life is shortened, and even the sealing function is completely lost. In addition, the above contradiction is further exacerbated by the realization of compact design requirements for design load bearing capacity within a limited axial space. The traditional scheme is difficult to balance between 'small-gap high-pressure-bearing' and 'large-gap low-abrasion', and a novel magnetic fluid sealing structure capable of maintaining high pressure-bearing capacity on the premise of allowing larger assembly gap and simultaneously avoiding rigid friction abrasion is needed to meet urgent requirements of modern industry on high-reliability, long-service life and low-maintenance cost sealing technology. Disclosure of Invention The embodiment of the invention provides a self-adaptive magnetic pole extension type magnetic fluid sealing device and a magnetic fluid sealing method, which are used for solving the technical problems of how to overcome the contradiction that the bearing capacity is suddenly reduced when the sealing gap is increased and how to realize magnetic fluid sealing with high bearing capacity, low abrasion, easy processing and long service life in the prior art. In view of the above technical problems, an embodiment of the present invention provides a magnetic fluid sealing device with adaptive pole extension, including: the magnetic pole is provided with high magnetic permeability, saturation, magnetization intensity and low coercivity and is used for constructing a magnetic field loop; The permanent magnet is made of N38H neodymi