CN108061163A - A kind of staged device for sealing magnetic fluid - Google Patents

Abstract

The invention discloses a stepped magnetic fluid sealing device, which comprises a shaft, a casing, a pole shoe, a magnetic fluid and a permanent magnet. The shaft passes through and extends beyond both ends of the casing, and the shaft includes a stepped shaft part located inside the casing. , the diameter of the middle step of the stepped shaft part is the largest, and the diameters of the steps on the left and right sides decrease successively. The stepped shaft part has a plurality of first sides parallel to the axis of the shaft and a plurality of second sides perpendicular to the axis. The inner surface of the shell There are at least two pole shoes, and an annular permanent magnet is arranged between two adjacent pole shoes. The pole shoes have radial pole teeth protruding toward the first side and axial pole teeth protruding toward the second side. , both the radial pole teeth and the axial pole teeth are ring-shaped, and a magnetic fluid is provided between the radial pole teeth and the first side and between the axial pole teeth and the second side. The invention greatly enhances the pressure resistance capacity of the magnetic fluid seal, and overcomes the problem that the existing sealing device cannot meet the high sealing performance requirements under special working conditions such as high speed and heavy load.

Description

A stepped magnetic fluid sealing device

technical field

The invention belongs to the field of mechanical engineering sealing, and in particular relates to a stepped magnetic fluid sealing device capable of maintaining good sealing performance under high-speed and heavy-load working conditions.

Background technique

Compared with traditional sealing technology, magnetic fluid sealing technology has the advantages of zero leakage rate, no solid friction, long life, high reliability, etc., and has been widely used in various industries. When the magnetic fluid sealing technology is applied in a large diameter, high speed and heavy-duty sealing environment, the magnetic fluid in the sealing gap often fails because the sealing gap is too large, so improving the pressure resistance of the magnetic fluid seal under the condition of large gap is the current research One of the hot issues.

One of the methods to improve the pressure resistance performance of the magnetic fluid seal under large gaps is to increase the number of magnetic sources in the magnetic circuit of the magnetic fluid seal and improve the shape of the pole piece, as described in reference 1 (patent publication number CN 205663888U) Sealing device and the sealing device described in reference 2 (publication number is the patent of CN205877200U). Although the sealing performance of the two sealing devices described in the above documents has been greatly improved compared with ordinary magnetic fluid, there is still room for further improvement in the sealing performance of the existing sealing structure.

The magnetic fluid seal uses permanent magnets to generate a magnetic field force in the sealing gap to firmly fix the magnetic fluid in the sealing gap and resist the pressure difference on both sides, thereby achieving the effect of sealing; the purpose of the present invention is to provide a stepped magnetic fluid The sealing device solves the problem of low pressure resistance existing in the existing single magnetic source magnetic fluid sealing device and multi-magnetic source magnetic fluid sealing device, making this sealing technology successfully applied to high-speed and heavy-duty fields.

Contents of the invention

The purpose of the present invention is to provide a stepped magnetic fluid sealing device, so as to solve the problem of low pressure resistance existing in the existing sealing device, so that the sealing technology can be successfully applied in the fields of high speed and heavy load.

A stepped magnetic fluid sealing device, including a shaft, a housing, a pole piece, a magnetic fluid and a permanent magnet, is characterized in that the shaft passes through and extends beyond both ends of the housing, and the shaft includes a The stepped shaft part in the casing, the middle step diameter of the stepped shaft part is the largest, and the diameters of the steps on the left and right sides decrease successively, and the stepped shaft part has a plurality of first sides parallel to the axis of the shaft and a plurality of The second side perpendicular to the axis, at least two pole pieces are arranged on the inner surface of the housing, and a ring-shaped permanent magnet is arranged between two adjacent pole pieces, and the pole pieces are in a ring-shaped structure , the pole piece has radial pole teeth protruding toward the first side and axial pole teeth protruding toward the second side, the radial pole teeth and the axial pole teeth are ring-shaped, There is a sealing gap between the radial pole teeth and the first side and between the axial pole teeth and the second side, and the magnetic fluid is arranged in the sealing gap.

Further, a sealing ring is provided in the groove on the outer surface of the pole piece, and the sealing ring is used to seal the gap between the outer surface of the pole piece and the inner surface of the casing.

Further, the stepped shaft part is a symmetrical stepped shaft, separated by the middle step, and left and right symmetrical.

Further, it also includes two bearings and two magnetic isolation rings, the two magnetic isolation rings are respectively arranged on the left end surface of the leftmost pole piece and the right end surface of the rightmost pole piece, and the two bearings Installed on the shaft, they 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 the bearing is in contact with the inner surface of the housing.

Further, the number of the permanent magnets is 2-10, the permanent magnets are axially magnetized permanent magnets, and the directions of the magnetic force lines of two adjacent permanent magnets are opposite.

Further, the size of the sealing gap is 0.05-5mm.

Further, the cross-sections of the axial pole teeth and radial pole teeth are square or rectangular, respectively.

Further, 2-10 axial pole teeth and radial pole teeth of the pole shoe are respectively arranged side by side.

The present invention designs a stepped shaft and a stepped pole shoe structure. Pole teeth are evenly distributed on the inner ring surface and the side of the stepped pole shoe, and permanent magnets are embedded between the pole shoes. Ferrofluid is injected into the radial and axial sealing gaps to realize a stepped magnetic fluid seal. On the basis of the stepped magnetic fluid seal, the present invention greatly enhances the pressure resistance of the magnetic fluid seal by setting multi-level magnetic sources and improving the distribution of the pole teeth on the pole shoe; the stepped sealing structure can reduce the pressure of the magnetic fluid. The loss increases the secondary pressure bearing capacity and self-repairing capacity of the sealing device. The pressure resistance and sealing reliability of the magnetic fluid seal under the condition of a large gap are further improved, and its safe working range is expanded.

Description of drawings

FIG. 1 is a schematic structural diagram of a stepped magnetic fluid sealing device of the present invention.

In the figure: shaft 1, housing 2, bearing 3, magnetic isolation ring 4, end cover 5, pole shoe 6, sealing ring 7, permanent magnet 8, first side 9, second side 10, radial pole teeth 11, shaft 12 to the pole teeth.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Referring to FIG. 1 , a stepped magnetic fluid sealing device includes a shaft 1 , a casing 2 , a sealing ring 7 , a pole piece 6 , a magnetic fluid and a permanent magnet 8 , and the shaft 1 passes through and extends to both ends of the casing 2 In addition, the shaft 1 includes a stepped shaft part located in the housing 2. The middle step diameter of the stepped shaft part is the largest, and the diameters of the steps on the left and right sides decrease successively. The stepped shaft part has multiple The first side 9 of the axis of the shaft 1 and a plurality of second sides 10 perpendicular to the axis, the inner surface of the housing 2 is provided with at least two pole shoes 6, between two adjacent pole shoes 6 An annular permanent magnet 8 is arranged between them, the pole shoe 6 is a circular ring structure, the sealing ring 7 is installed in the groove on the outer surface of the pole shoe 6, and the pole shoe 6 has The radial pole teeth 11 protruding toward the first side 9 and the axial pole teeth 12 protruding toward the second side 10, the radial pole teeth 11 and the axial pole teeth 12 are both annular, There is a sealing gap between the radial pole teeth 11 and the first side 9, and between the axial pole teeth 12 and the second side 10, and the magnetic fluid (not shown in the figure) is arranged in the sealing gap. ). The inner diameter of the pole piece 6 changes adaptively with the change of the stepped diameter of the stepped shaft. Each pole piece 6 forms two kinds of magnetic fluid seals with the shaft 1 through radial pole teeth 11, axial pole teeth 12, as shown in Fig. 1 The manner in which the pole piece 6 is arranged correspondingly to the two surfaces of the stepped shaft's negative angle is shown, but the pole piece 6 may also be arranged in a manner corresponding to the two surfaces of the stepped shaft's male angle. The material of the shaft 1 is preferably 2cr13 stainless steel, the material of the shell 2 is preferably non-magnetic stainless steel, and the material of the pole piece 6 is preferably 2cr13 stainless steel. The present invention forms multiple magnetic fluid seals through multiple pole pieces and multiple permanent magnets, and each pole piece forms magnetic fluid seals in two directions, which greatly enhances the effect of sealing, thereby greatly enhancing the pressure resistance of the magnetic fluid seal .

Further, the stepped shaft part is a symmetrical stepped shaft, separated by the middle step, and left and right symmetrical.

Further, it also includes two bearings 3 and two magnetic isolation rings 4, and the two magnetic isolation rings 4 are respectively arranged on the left end surface of the leftmost pole piece 6 and the right end surface of the rightmost pole piece 6 Above, two bearings 3 are installed on the shaft 1, respectively set on the left side of the left magnetic isolation ring 4 and the right side of the right magnetic isolation ring 4, and the outer ring of the bearing 3 is in contact with the inner surface of the housing 2.

Further, the number of the permanent magnets 8 is 2-10.

Further, the size of the sealing gap is 0.05-5mm.

Further, the cross-sections of the radial pole teeth 11 and the axial pole teeth 12 are square or rectangular, respectively.

Further, 2-10 radial pole teeth 11 and axial pole teeth 12 of the pole shoe 6 are respectively arranged side by side.

The installation process of the stepped magnetic fluid sealing device of the present invention is as follows: the sealing ring 7 is installed in the groove on the outer surface of the pole piece 6, and the plurality of pole pieces 6 and permanent magnets 8 are respectively corresponding to the steps of the stepped shaft. Install it on the shaft 1 in sequence, inject the magnetic fluid into the sealing gap formed by the pole shoe 6 and the shaft 1, install the magnetic isolation ring 4 and the bearing 3 on the outside of the pole shoe 6 on the left and right sides respectively to form a sealing assembly, and put the sealing assembly Installed in the casing 2, the outer ring of the bearing 3 on the left abuts against the positioning part of the casing 2, the outer ring of the bearing 3 on the right abuts against the end cover 5, and the end cover 5 is screwed to the inner surface of the casing 2, A stepped magnetic fluid seal is realized.

Finally, it should be noted that: in the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. For the convenience of description, if the words "up", "down", "left" and "right" appear in the following, it only means that the directions of up, down, left and right are consistent with the drawings themselves, and do not limit the structure. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be described in the foregoing embodiments Modifications are made to the recorded technical solutions, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (8)

1. A stepped magnetic fluid sealing device, comprising a shaft, a housing, a pole piece, a magnetic fluid and a permanent magnet, characterized in that the shaft passes through and extends beyond the two ends of the housing, and the shaft includes a In the stepped shaft part in the housing, the middle step diameter of the stepped shaft part is the largest, and the diameters of the steps on the left and right sides decrease successively, and the stepped shaft part has a plurality of first sides parallel to the axis of the shaft and A plurality of second side surfaces perpendicular to the axis, at least two pole pieces are provided on the inner surface of the housing, and a ring-shaped permanent magnet is arranged between two adjacent pole pieces, and the pole pieces are circular rings structure, the pole shoe has radial pole teeth protruding toward the first side and axial pole teeth protruding toward the second side, and both the radial pole teeth and the axial pole teeth are rings shape, between the radial pole teeth and the first side and between the axial pole teeth and the second side are sealing gaps, and the magnetic fluid is arranged in the sealing gaps. 2. A stepped magnetic fluid sealing device according to claim 1, characterized in that a sealing ring is arranged in the groove on the outer surface of the pole piece, and the sealing ring is used to seal the outer surface of the pole piece. The gap between the circular face and the inner surface of the housing. 3 . The stepped magnetic fluid sealing device according to claim 1 , wherein the stepped shaft part is a symmetrical stepped shaft, separated by a middle step, and left and right symmetrical. 4 . 4. A stepped magnetic fluid sealing device according to claim 1, characterized in that it further comprises two bearings and two magnetic isolation rings, and the two magnetic isolation rings are respectively arranged at the leftmost pole On the left end face of the shoe and the right end face of the rightmost pole shoe, two bearings are installed on the shaft, which are respectively arranged on the left side of the left magnetic isolation ring and the right side of the right magnetic isolation ring. The outer ring of the bearing and the The inner surface of the housing is in contact. 5. A stepped ferrofluid sealing device according to claim 1, wherein the number of said permanent magnets is 2-10, said permanent magnets are axially magnetized permanent magnets, and adjacent The magnetic field lines of the two permanent magnets are in opposite directions. 6 . The stepped magnetic fluid sealing device according to claim 1 , wherein the size of the sealing gap is 0.05-5 mm. 7 . The stepped magnetic fluid sealing device according to claim 1 , wherein the cross-sections of the axial pole teeth and the radial pole teeth are square or rectangular, respectively. 8 . 8 . The stepped ferrofluid seal device according to claim 1 , wherein 2-10 axial pole teeth and radial pole teeth of the pole shoe are respectively arranged side by side.