CN113757384B - Magnetic fluid sealing device with axial through hole structure magnetic source - Google Patents

Abstract

The invention relates to a magnetic fluid seal with an axial through-hole structure magnetic source, which comprises a casing, a left pole shoe ring, a right pole shoe ring and a permanent magnet ring. The invention solves the problems of data collection, positioning, communication, and difficult processing of permanent magnet rings, which are commonly used in magnetic liquid sealing, and can place data monitoring devices, such as temperature sensors, speed sensors, etc. Collect; or process threads at the through holes to meet the fixing needs of the ring magnet, so that the magnetic liquid seal can well solve the above problems in engineering on the one hand, and on the other hand, it makes the permanent magnet structure lighter and reduces the friction of the rotating shaft. load.

Description

Magnetic fluid sealing device with magnetic source with axial through-hole structure

technical field

The invention belongs to the field of mechanical engineering sealing, in particular to a magnetic fluid sealing device with an axial through-hole structure magnetic source.

Background technique

Magnetic fluid seal is to use permanent magnets to generate magnetic field force in the sealing gap to firmly fix the magnetic fluid in the sealing gap to resist the pressure difference on both sides, so as to achieve the sealing effect.

In some sealing occasions, in addition to the need to seal the sealed chamber and the external environment, there are also the problems of adding magnetic liquid, data collection, positioning, and connection. Referring to the field of mechanical engineering, the first method that comes to mind is to process the connection on the permanent magnet. Through hole, but because the through hole structure on the permanent magnet will weaken the pressure resistance of the magnetic liquid sealing device to a certain extent, and the commonly used rubidium iron boron magnet is a brittle and hard material that is difficult to process, its excessive processing is easy to cause The permanent magnets are broken, so the magnetic fluid seal has never had a similar structure.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a magnetic fluid sealing device with an axial through-hole structure magnetic source, the through-hole structure can be used as the placement position of the magnetic field, temperature, speed measuring device and the addition channel of the magnetic liquid during operation, and can also be processed The thread not only reduces the weight of the sealing device and the load on the rotating shaft, but also solves the problems of adding magnetic liquid, data collection, positioning and communication existing in the existing sealing device.

In this patent, finite element simulation is carried out for a large number of magnetic liquid sealing examples, the simulation results are analyzed, and a reasonable design scheme for the size and position of the through-hole structure is proposed.

The technical scheme of the present invention is as follows: the magnetic fluid seal with an axial through-hole magnetic source includes a casing, a left pole shoe ring, a right pole shoe ring and a permanent magnet; the left pole shoe ring, the right pole The shoe ring and the permanent magnet are arranged on the inner wall of the casing, and there is a space between the inner circular surface of the left pole shoe ring and the right pole shoe ring and the outer circular surface of the shaft; the outer circular surface of the shaft is provided with pole teeth , the pole teeth extend radially to the inner circular surfaces of the left pole shoe ring and the right pole shoe ring, leaving a gap therebetween, and the gap is filled with magnetic fluid for sealing. The permanent magnet is made of sintered NdFeB, and there are axially communicating through holes on it. When the diameter of the through hole is greater than two-thirds of the radial width of the permanent magnet, the withstand voltage value will drop significantly. Sintered NdFeB materials are brittle and hard materials that are difficult to process. The large size of the through hole will lead to difficult processing and the permanent magnet is easy to break. In order to provide sufficient withstand voltage value for the magnetic liquid seal, the axial communication through hole should be set far away from At the radial edge of the permanent magnet, the diameter of the axial communication through hole is less than two-thirds of the radial width of the permanent magnet.

The magnetic fluid seal with an axial through-hole structure magnetic source is characterized in that the number of pole teeth provided on the outer circular surface of the shaft is 4-10.

The magnetic fluid seal with an axial through-hole structure magnetic source is characterized in that the size of the gap between the pole teeth and the inner circular surfaces of the left pole shoe ring and the right pole shoe ring is 0.05-3 mm .

The magnetic fluid seal with an axial through-hole structure magnetic source is characterized in that: the permanent magnet is an axially magnetized permanent magnet.

The magnetic fluid seal with an axial through-hole structure magnetic source is characterized in that: the outer circular surface of the left pole shoe ring and the right pole shoe ring is provided with a ring groove, and the ring groove is provided with a ring groove. Has sealing ring.

The magnetic fluid seal with an axial through-hole structure magnetic source is characterized in that: it further includes a left magnetic isolation ring and a right magnetic isolation ring; the left magnetic isolation ring and the right magnetic isolation ring are arranged on the inner wall of the casing Above, the left magnetic isolation ring is located on the left side of the left pole shoe ring, and the right magnetic isolation ring is located on the right side of the right pole shoe ring.

The magnetic fluid seal with an axial through-hole magnetic source is characterized in that it further includes a left bearing and a right bearing, the left bearing and the right bearing are respectively sleeved on the shaft, and the left bearing is arranged on the shaft. The left side of the left magnetic isolation ring is in contact with the left magnetic isolation ring; the right bearing is arranged on the right side of the right magnetic isolation ring and is in contact with the right magnetic isolation ring.

The present invention uses the classic magnetic liquid sealing structure in which the left pole shoe ring, the permanent magnet and the right pole shoe ring are sequentially arranged on the inner wall of the casing, so that the magnetic force line of the permanent magnet forms a loop through the pole shoe and the shaft, and under the action of the pole teeth , through the design of the structure of the left pole shoe ring, the permanent magnet and the right pole shoe ring, the magnetic field lines generated by the permanent magnet can pass through the pole shoe as far as possible through the pole teeth to reach the magnetic liquid ring, which can greatly reduce the The occurrence of magnetic flux leakage. The through hole is arranged at a position away from the rotating shaft, and its diameter is smaller than the radial width of the magnet. Such a structural design can ensure that the magnetic liquid seal has a sufficient withstand voltage value.

Description of drawings

1 is a schematic structural diagram of a multi-magnetic source square magnetic fluid sealing device provided by an embodiment of the present invention; each serial number in the figure and the corresponding names are as follows: 1-shaft, 2-shell, 3-left pole shoe ring, 4- Permanent magnet, 5-axial through hole, 6-right pole shoe ring, 7-pole tooth, 8-right bearing, 9-right magnetic isolation ring, 10-sealing ring, 11-left magnetic isolation ring, 12-right Bearing, 13-end cover.

Detailed ways

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

As shown in Figure 1, the described magnetic fluid seal with an axial through-hole magnetic source includes a housing, a left pole shoe ring, a right pole shoe ring and a permanent magnet; the left pole shoe ring, right The pole shoe ring and the permanent magnet are arranged on the inner wall of the casing, and there is a space between the inner circular surface of the left and right pole shoe rings and the outer circular surface of the shaft; the outer circular surface of the shaft is provided with a pole The pole teeth extend radially toward the inner circular surfaces of the left pole shoe ring and the right pole shoe ring, leaving a gap therebetween, and the gap is filled with magnetic fluid for sealing. The permanent magnet is made of sintered NdFeB, and there are axially communicating through holes on it. When the diameter of the through hole is greater than two-thirds of the radial width of the permanent magnet, the withstand voltage value will drop significantly. Sintered NdFeB materials are brittle and hard materials that are difficult to process. Excessive through-hole size will lead to difficult processing and permanent magnets are easy to break. In order to provide sufficient withstand voltage for the magnetic liquid seal, the communicating through-holes should be placed far away from the permanent magnets. At the radial edge, the diameter of the communicating through hole should be less than two-thirds of the radial width of the permanent magnet.

The magnetic fluid seal with an axial through-hole structure magnetic source is characterized in that the number of pole teeth provided on the outer circular surface of the shaft is 4-10.

The magnetic fluid seal with an axial through-hole structure magnetic source is characterized in that the size of the gap between the pole teeth and the inner circular surfaces of the left pole shoe ring and the right pole shoe ring is 0.05-3 mm .

The magnetic fluid seal with an axial through-hole structure magnetic source is characterized in that: the permanent magnet is an axially magnetized permanent magnet.

The magnetic fluid seal with an axial through-hole structure magnetic source is characterized in that: the outer circular surface of the left pole shoe ring and the right pole shoe ring is provided with a ring groove, and the ring groove is provided with a ring groove. Has sealing ring.

The magnetic fluid seal with an axial through-hole structure magnetic source is characterized in that: it further includes a left magnetic isolation ring and a right magnetic isolation ring; the left magnetic isolation ring and the right magnetic isolation ring are arranged on the inner wall of the casing Above, the left magnetic isolation ring is located on the left side of the left pole shoe ring, and the right magnetic isolation ring is located on the right side of the right pole shoe ring. The magnetic isolation ring is located to the right of the right pole shoe ring.

The magnetic fluid seal with an axial through-hole magnetic source is characterized in that it further includes a left bearing and a right bearing, the left bearing and the right bearing are respectively sleeved on the shaft, and the left bearing is arranged on the shaft. The left side of the left magnetic isolation ring is in contact with the left magnetic isolation ring; the right bearing is arranged on the right side of the right magnetic isolation ring and is in contact with the right magnetic isolation ring.

Claims (7)

1. A magnetic fluid seal with an axial through-hole structure magnetic source, comprising a housing (2), a left pole shoe ring (3), a permanent magnet (4) and a right pole shoe ring (6); it is characterized in that: The left pole shoe ring (3), the permanent magnet (4) and the right pole shoe ring (6) are arranged on the inner wall of the housing (2). There is a space between the inner circular surface and the outer circular surface of the shaft (1); the outer circular surface of the shaft (1) is provided with pole teeth (7), and the pole teeth (7) are radially leftward The inner circular surfaces of the pole shoe ring (3) and the right pole shoe ring (6) extend, leaving a gap therebetween, the gap is filled with magnetic fluid for sealing, and the permanent magnet (4) is made of sintered NdFeB , there is an axial communication through hole (5) on it. When the diameter of the through hole is greater than two-thirds of the radial width of the permanent magnet, the withstand voltage value will drop significantly, and the sintered NdFeB material is difficult to process. Brittle and hard materials, if the size of the through hole is too large, it will be difficult to process, and the permanent magnet is easy to break. In order to provide sufficient pressure resistance for the magnetic liquid seal, the axial communication through hole should be set away from the radial edge of the permanent magnet. The diameter of the communicating through hole is smaller than two-thirds of the radial width of the permanent magnet. 2 . The magnetic fluid seal with an axial through-hole magnetic source according to claim 1 , wherein the number of pole teeth ( 7 ) provided on the outer circular surface of the shaft ( 1 ) ranges from 4 to 4 . 10. 3. The magnetic fluid seal with an axial through-hole structure magnetic source according to claim 1, characterized in that: the pole teeth (7) are connected with the left pole shoe ring (3) and the right pole shoe ring (6). ), the size of the gap between the inner circular surfaces is 0.05 to 3 mm. 4. The magnetic fluid seal with an axial through-hole magnetic source according to claim 1, wherein the permanent magnet (4) is an axially magnetized permanent magnet. 5. The magnetic fluid seal with an axial through-hole structure magnetic source according to claim 1, characterized in that: the outer circular surfaces of the left pole shoe ring (3) and the right pole shoe ring (6) A ring groove is provided, and a sealing ring (10) is arranged in the ring groove. 6. The magnetic fluid seal with an axial through-hole structure magnetic source according to claim 1, characterized in that: further comprising a left magnetic isolation ring (11) and a right magnetic isolation ring (9); The magnetic ring (11) and the right magnetic isolation ring (9) are arranged on the inner wall of the casing (2), the left magnetic isolation ring (11) is located on the left side of the left pole shoe ring (3), and the right magnetic isolation ring (9) is located on the left Right side of right pole shoe ring (6). 7. The magnetic fluid seal with an axial through-hole structure magnetic source according to claim 1, characterized in that it further comprises a left bearing (12) and a right bearing (8), the left bearing (12) and the The right bearing (8) is respectively sleeved on the shaft (1), the left bearing (12) is arranged on the left side of the left magnetic isolation ring (11), and is in contact with the left magnetic isolation ring (11); the right bearing (12) 8) It is located on the right side of the right magnetic isolation ring (9), and is in contact with the right magnetic isolation ring (9).

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