Mixed type magnetic source magnetic fluid sealing device
Technical Field
The invention belongs to the field of mechanical engineering sealing, and particularly relates to a hybrid magnetic source magnetic fluid sealing device capable of keeping good sealing performance under a high-speed heavy-load working condition.
Background
In the magnetic fluid sealing device, the performance of the magnetic fluid gradually loses efficacy along with the increase of the sealing gap, so the pressure resistance of the sealing device is reduced, and although the current magnetic fluid sealing technology is applied to the environment with large diameter and high speed heavy load sealing, the problem to be solved at present is to improve the pressure resistance of the magnetic fluid sealing under the large gap.
One of the methods for improving the pressure resistance of the magnetic fluid seal under a large gap is to improve the magnetic fluid seal structure such as the seal device described in reference 1 (patent publication No. CN 205663888U) and the seal device described in reference 2 (patent publication No. CN 205877200U). Although the sealing performance of the two sealing devices disclosed in the above documents is greatly improved compared with that of a common magnetic fluid, the sealing performance of the two sealing devices still cannot meet the requirement of high sealing performance under special working conditions such as high speed and heavy load.
The magnetic fluid seal is characterized in that magnetic field force generated by a permanent magnet in a seal gap is utilized to firmly fix the magnetic fluid in the seal gap and resist the pressure difference at two sides, so that the sealing effect is achieved; the invention aims to provide a sealing device of a mixed magnetic source magnetic fluid, which can solve the problem of low pressure resistance of the magnetic fluid seal, so that the sealing technology can play a good role in the field of high speed and heavy load.
Disclosure of Invention
The invention aims to provide a hybrid magnetic source magnetic fluid sealing device, so that the problem of low pressure resistance of the existing sealing device is solved, and the sealing technology is successfully applied to the fields of high speed and heavy load and the like.
A hybrid magnetic source magnetic fluid sealing device comprises a shaft, a shell, pole shoes, magnetic fluid and permanent magnets, and is characterized in that the shaft penetrates through and extends out of two ends of the shell, at least two pole shoes are arranged on the inner surface of the shell, annular first permanent magnets are arranged between every two adjacent pole shoes, the pole shoes are of an annular structure, the shaft penetrates through inner holes of the pole shoes, annular radial pole teeth protruding towards the shaft are arranged on the inner circular surfaces of the pole shoes, annular second permanent magnets are arranged on positions, corresponding to the radial pole teeth, of the shaft, a sealing gap is formed between each second permanent magnet and the corresponding radial pole teeth, the magnetic fluid is arranged in the sealing gap, the first permanent magnets are axial magnetizing permanent magnets, the second permanent magnets are radial magnetizing permanent magnets, and the magnetic force lines of the two adjacent first permanent magnets are opposite, the magnetic lines of force of the two adjacent second permanent magnets are opposite, and the magnetic poles of the first permanent magnet and the second permanent magnet facing the same pole shoe are opposite.
Further, the second permanent magnet is arranged in the annular groove of the shaft, and the outer diameter of the second permanent magnet is the same as the diameter of the shaft.
Furthermore, a step is arranged between two adjacent second permanent magnets on the shaft, the diameter of the step is larger than that of the shaft, annular axial pole teeth are arranged on the pole shoe corresponding to the shaft shoulder of the step, a sealing gap is formed between the axial pole teeth and the shaft shoulder, and the magnetic fluid is arranged in the sealing gap.
Furthermore, the second permanent magnet is a split permanent magnet and is composed of a plurality of equal-size splits.
Further, a sealing ring is arranged in a groove in the outer circular surface of the pole shoe and used for sealing a gap between the outer circular surface of the pole shoe and the inner surface of the shell.
The magnetic isolation device is characterized by further comprising two bearings and two magnetic isolation rings, wherein the two magnetic isolation rings are respectively arranged on the left end face of the leftmost pole shoe and the right end face of the rightmost pole shoe, the two bearings are arranged on the shaft and are respectively arranged on the left side of the left magnetic isolation ring and the right side of the right magnetic isolation ring, and the outer ring of each bearing is in contact with the inner surface of the shell.
Further, the number of the first permanent magnets is 2-6, and the number of the second permanent magnets is one more than that of the first permanent magnets.
Further, the size of the sealing gap is 0.05-3 mm.
Further, the cross sections of the axial pole teeth and the radial pole teeth are respectively square or rectangular.
Furthermore, 2-6 axial pole teeth and radial pole teeth of the pole shoe are respectively arranged in parallel.
The invention realizes the hybrid magnetic source magnetic fluid seal by arranging pole teeth on the inner circle surface and the end surface of the stepped pole shoe, arranging a groove on the shaft, arranging the split permanent magnet, corresponding to the pole teeth on the pole shoe and injecting magnetic fluid into the radial and axial seal gaps formed by the pole teeth and the stepped shaft. The invention can greatly reduce the length of the magnetic circuit, increase the magnetic field intensity in the sealing gap, reduce the loss amount of the magnetic fluid, greatly improve the pressure resistance and the sealing reliability of the magnetic fluid seal and enlarge the safe working range of the magnetic fluid seal.
Drawings
Fig. 1 is a schematic structural diagram of a hybrid magnetic source magnetic fluid sealing device according to the present invention.
In the figure: the magnetic field generator comprises a shaft 1, a shell 2, a bearing 3, a magnetism isolating ring 4, an end cover 5, a pole shoe 6, a sealing ring 7, a first permanent magnet 8, a second permanent magnet 9, a step 10, a radial pole tooth 11, an axial pole tooth 12 and a shaft shoulder 13.
Detailed Description
The present invention is described in further detail below with reference to the attached drawing figures.
Referring to fig. 1, a hybrid magnetic source magnetic fluid sealing device includes a shaft 1, a housing 2, pole shoes 6, a magnetic fluid and a first permanent magnet 8, the shaft 1 penetrates and extends to the outside of two ends of the housing 2, at least two pole shoes 6 are arranged on the inner surface of the housing 2, an annular first permanent magnet 8 is arranged between two adjacent pole shoes 6, the pole shoes are of an annular structure, the shaft penetrates through an inner hole of the pole shoe 6, an inner circular surface of the pole shoe 6 is provided with an annular radial pole tooth 11 protruding toward the shaft 1, an annular second permanent magnet 9 is arranged at a position of the shaft 1 corresponding to the radial pole tooth 11, a sealing gap is formed between the second permanent magnet 9 and the radial pole tooth 11, the magnetic fluid is arranged in the sealing gap, the first permanent magnet 8 is an axial magnetizing type permanent magnet, the second permanent magnet 9 is a radial magnetizing type permanent magnet, the magnetic lines of force of two adjacent first permanent magnets 8 are opposite, the magnetic lines of force of two adjacent second permanent magnets 9 are opposite, and the magnetic poles of the first permanent magnets 8 and the magnetic poles of the second permanent magnets 9 facing to the same pole shoe 6 are opposite. Fig. 1 shows a case where two pole pieces 6 and one first permanent magnet 8 are provided, but the pole pieces 6 and the first permanent magnet 8 are each provided with two or more in the axial direction, and the first permanent magnet 8 is provided between adjacent two pole pieces 6. The material of the shaft 1 is preferably 2cr13 stainless steel, the material of the housing 2 is preferably non-magnetic stainless steel, and the material of the pole piece 6 is preferably 2cr13 stainless steel.
Furthermore, a step 10 is arranged between two adjacent second permanent magnets 9 on the shaft 1, the diameter of the step 10 is larger than that of the shaft 1, the pole shoe 6 is provided with an annular axial pole tooth 12 corresponding to a shaft shoulder 13 of the step 10, a sealing gap is formed between the axial pole tooth 12 and the shaft shoulder 13, and the magnetic fluid is arranged in the sealing gap. According to the invention, multiple magnetic fluid seals are formed by the plurality of pole shoes and the plurality of permanent magnets, and each pole shoe forms magnetic fluid seals in two directions, so that the sealing effect is greatly enhanced, and the pressure resistance of the magnetic fluid seal is greatly enhanced.
Further, the second permanent magnet 9 is arranged in the annular groove of the shaft 1, and the outer diameter of the second permanent magnet 9 is the same as the diameter of the shaft 1.
Further, the second permanent magnet 9 is a split permanent magnet and is composed of a plurality of equal-sized split pole shoes, and the pole shoe 6 is a split pole shoe and is composed of a plurality of equal-sized split pole shoes.
Further, a sealing ring 7 is arranged in a groove on the outer circular surface of the pole shoe 6, and the sealing ring 7 is used for sealing a gap between the outer circular surface of the pole shoe 6 and the inner surface of the shell 2.
Further, the hybrid magnetic source magnetic fluid sealing device further comprises two bearings 3 and two magnetism isolating rings 4, the two magnetism isolating rings 4 are respectively arranged on the left end face of the leftmost pole shoe 6 and the right end face of the rightmost pole shoe 6, the two bearings 3 are arranged on the shaft 1 and are respectively arranged on the left side of the left magnetism isolating ring 4 and the right side of the right magnetism isolating ring 4, and the outer rings of the bearings 3 are in contact with the inner surface of the shell 2.
Further, the number of the first permanent magnets 8 is 2-6, and the number of the second permanent magnets 9 is one more than that of the first permanent magnets.
Further, the size of the sealing gap is 0.05-3 mm.
Further, the axial teeth 12 and the radial teeth 11 have square or rectangular cross sections respectively.
Furthermore, 2 to 6 axial pole teeth 12 and radial pole teeth 11 of the pole shoe 6 are respectively arranged in parallel.
The mixed magnetic source magnetic fluid sealing device of the invention has the following installation process: installing a sealing ring 7 in a groove on the outer circular surface of a pole shoe 6, installing a second permanent magnet 9 in an annular groove on a shaft 1, installing a plurality of pole shoes 6 and a plurality of first permanent magnets 8 on the shaft 1 corresponding to steps 10 respectively, injecting magnetic fluid into a sealing gap formed by the pole shoes 6, the shaft 1 and an axial pole tooth 12 and a shaft shoulder, installing a magnetism isolating ring 4 and a bearing 3 on the outer sides of the pole shoes 6 on the left side and the right side respectively to form a sealing assembly, installing the sealing assembly in a shell 2, abutting the outer ring of the left bearing 3 against the positioning part of the shell 2, abutting the outer ring of the right bearing 3 against an end cover 5, and connecting the end cover 5 with the inner surface of the shell 2 in a threaded manner, thereby realizing the multi-magnetic.
Finally, it should be noted that: the embodiments and features of the embodiments of the present invention may be combined with each other without conflict. For convenience of description, the words "upper", "lower", "left" and "right" in the following description are used only to indicate the correspondence between the upper, lower, left and right directions of the drawings themselves, and do not limit the structure. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.