CN101645644B - Permanent magnetic compound type asynchronous coupling - Google Patents

Abstract

The invention provides a permanent magnet composite asynchronous shaft coupling. It includes three parts: a built-in tangential permanent magnet pole active rotor, a composite driven rotor, and an isolation cover. The invention realizes transmission through magnetic field coupling, and is a permanent magnet asynchronous coupling with slip between the driving side and the driven side. In particular, a permanent magnet asynchronous coupling in which the driving side rotor adopts a built-in tangential permanent magnet structure, the driven side rotor adopts a composite structure, and relies on eddy currents to form a magnetic field of the driven side rotor. The invention overcomes the shortcomings of the existing permanent magnet asynchronous coupling, improves performance, expands the scope of application, and can be used in the full slip range, whether it is light load, heavy load, or low speed, high speed and other transmission occasions and stable Both state and dynamic process have excellent mechanical properties.

Description

Permanent magnet composite asynchronous coupling

(1) Technical field

The invention relates to a shaft coupling. Especially a permanent magnet asynchronous coupling.

(2) Background technology

With the development of permanent magnet materials, electrical materials and other technologies, as well as the improvement of electromagnetic field analysis methods and means, permanent magnet couplings, as a new type of mechanical transmission device, have begun to be widely used in environments with special requirements for sealing, such as Petroleum, chemical, vacuum, cryogenic, pharmaceutical, food, aviation and other fields. According to the speed relationship between the driving rotor and the driven rotor, permanent magnet couplings can be divided into permanent magnet synchronous couplings and permanent magnet asynchronous couplings. Permanent magnet synchronous coupling, such as patent 93112868.4, there are permanent magnet poles made of permanent magnet materials on the surface of both the driving rotor and the driven rotor, so the speed of the driven rotor must be kept in sync with the speed of the driving rotor in order to work stably. The structure of the permanent magnet coupling is only suitable for occasions that require high speed accuracy. The eddy current permanent magnet asynchronous coupling uses the permanent magnet poles to form a magnetic field on one side (the driving side or the driven side), and at the same time uses the eddy current to form a magnetic field on the other side (the driven side or the driving side). The two magnetic fields interact to realize the transmission . The existing eddy current permanent magnet asynchronous couplings can be classified into two types according to the structure of the rotor on the eddy current magnetic field side: the first type, the eddy current circuit and the magnetic circuit are in the same structural component during operation, for example, the publication number is In the patent document of GR3026455 (T3), the performance of the coupling with this structure is similar to that of a solid rotor motor, and it can provide a large electromagnetic torque when the slip is running, but when the slip decreases The torque drops rapidly, the mechanical properties are too soft, and the heat is serious, and the transmission efficiency is low; the second type is that the eddy current circuit and the magnetic circuit are in different structural components during operation, such as the patent document with the publication number GB719303(A), which has The performance of the coupling with this structure is similar to that of a squirrel-cage rotor motor, and its mechanical characteristics are better when the slip is small, but when the slip is greater than a certain value (critical slip), the slip The torque decreases rapidly, the mechanical characteristics deteriorate, and it cannot even meet the requirements of stable operation with load, and it cannot start with heavy load. In addition, whether the existing permanent magnet couplings are synchronous or asynchronous, most of the permanent magnets adopt a surface-mounted structure, which is not conducive to the improvement of the magnetic flux density of the coupling magnetic field, and cannot meet the needs of high-speed transmission.

(3) Contents of the invention

The purpose of the present invention is to provide a permanent magnet composite asynchronous coupling with excellent mechanical characteristics and wide application range, whether it is light load, heavy load, low speed, high speed and other transmission occasions, as well as in steady state and dynamic process. .

The purpose of the present invention is achieved like this:

The permanent magnet composite asynchronous coupling of the present invention includes three parts: a built-in tangential permanent magnet pole active rotor, a composite driven rotor, and an isolation cover; the built-in tangential permanent magnet pole active rotor consists of a magnetic isolation sleeve 1, The permanent magnetic pole 2 and the first iron core 3 are composed of the magnetic isolation sleeve 1 for connecting the output shaft of the prime mover. The first iron core 3 is made of solid ferromagnetic material. The first iron core 3 and the magnetic isolation sleeve 1 The permanent magnetic poles 2 are made of permanent magnetic materials and placed in the axial slots in the first iron core 3; the composite driven rotor consists of a sleeve 4, a first end ring 5, and a second end ring 13 , guide bar 6, second iron core 7, base 8, and second end cover 12. The sleeve 4 is made of ferromagnetic material, and the second iron core 7 is made of laminated silicon steel sheets. In the second iron core 7 The inner surface is provided with axial grooves evenly distributed along the circumference, and guide bars 6 are placed in the grooves. The guide bars 6 are made of metal conductors with good electrical conductivity. The two ends of each guide bar 6 pass through the first end ring 5 and the second ring respectively. The end rings 13 are shorted together, and the first end ring 5 and the second end ring 13 are also made of a metal conductor with good electrical conductivity. The sleeve 4, the first end ring 5, the second end ring 13, the guide bar 6 and The second iron core 7 is fixed by the base 8, and the base 8 is used to connect with the driven shaft; the isolation cover 9 is made of non-ferromagnetic material, and is fixed on other equipment through the mounting hole 10; between the driving rotor and the isolation cover 9 There is a first air gap 14 between them, and a second air gap 15 is between the driven rotor and the isolation cover 9 .

The present invention may also include:

1. The magnetization direction of the first iron core 3 is the tangential direction of the circumference, that is, the magnetization direction is perpendicular to the radial direction of the rotor, and the number of permanent magnet poles 2 is an even number, and is uniform along the circumference direction inside the first iron core 3 Placed so that two adjacent permanent magnet poles are opposite to the surface of the same polarity.

2. A first end cover 11 is provided on the left side of the active rotor, and the first end cover 11 is made of a non-magnetic material.

3. The magnetic permeability of the sleeve 4 is lower than that of the silicon steel sheet forming the second iron core 7 .

4. The axial effective length of the guide bar 6 in the composite driven rotor, that is, the length between the two end rings is equal to the axial length of the permanent magnet pole 2 in the active rotor, and is in the same direction as the permanent magnet pole 2 in the axial direction. align.

5. A second end cover 12 is provided on the left side of the driven rotor.

working principle:

The permanent magnetic poles on the active rotor form the active rotor magnetic field, which is coupled with the driven rotor through the isolation cover 9 . The output shaft of the prime mover and the magnetic isolation bushing 1 on the driving rotor of the coupling are fixed together by key connection or tight fit. When the prime mover drives the driving rotor to rotate, the magnetic field formed by the driving rotor rotates with it.

When running with a large slip rate, such as heavy load, initial stage of starting, etc., the depth of the magnetic field of the active rotor penetrating into the driven rotor is smaller than the thickness of the sleeve 4, and cannot enter the iron core 7. At this time, the path of working magnetic flux is: N pole of permanent magnet pole 2→iron core 3→air gap 14→isolation cover 9→air gap 15→sleeve 4→air gap 15→isolation cover 9→air gap 14→iron core 3 →S pole of permanent magnet pole 2. Due to the relative motion between the driven rotor and the active rotor magnetic field, the active rotor magnetic field generates eddy currents (ie induced currents) inside the sleeve 4 . According to the electromagnetic characteristics of ferromagnetic materials, in the equivalent circuit of eddy current, the resistance value is similar to the leakage reactance value, and the impedance value is very large when the slip is large. Therefore, although the induced electromotive force is large at this time, the amplitude of the eddy current is effectively limited, and at the same time, its active current component can generate a large enough electromagnetic torque to drive the driven rotor, driven shaft and load to rotate to achieve transmission.

When operating with a small slip, the depth of the active rotor magnetic field penetrating into the driven rotor is greater than the thickness of the sleeve 4 and enters the iron core 7 . Since the silicon steel sheet constituting the iron core 7 has a higher magnetic permeability than the sleeve 4, the main working flux path is: N pole of the permanent magnet pole 2 → iron core 3 → air gap 14 → isolation cover 9 → air gap 15 → sleeve Barrel 4→iron core 7→sleeve 4→air gap 15→isolation cover 9→air gap 14→iron core 3→S pole of permanent magnetic pole 2. At this time, the leakage reactance in the equivalent circuit of the driven rotor is very small, and the distribution of the induced current mainly depends on the resistance parameters, because the iron core 7 and the sleeve 4 are respectively composed of silicon steel sheets laminated and ferromagnetic materials, and their equivalent resistance is very large Due to the resistance of the loop formed by the guide bar 6, the end ring 5, and the end ring 13, the induced current inside the driven rotor is mainly located in the loop formed by the guide bar 6, the end ring 5, and the end ring 13, and the The leakage reactance value is much smaller than the resistance value. Therefore, when the small slip is running, although the induced electromotive force inside the driven rotor is very small, the value of the induced current generated is significantly lower than that of the large slip running, but the active current component does not change much, and it can still be generated. The similar electromagnetic torque during slip operation drives the driven rotor, driven shaft and load to rotate to realize transmission.

Beneficial effect:

(1) Since the existing permanent magnet asynchronous coupling only has a single eddy current circuit, when the slip rate changes, the active current component changes greatly, and the electromagnetic torque fluctuates obviously, resulting in too soft mechanical properties, which cannot meet the full requirements. Transmission within the slip range. When the permanent magnet asynchronous coupling proposed by the present invention is running at a large slip rate, the steel sleeve 4 forms an eddy current circuit; when it is running at a small slip rate, the guide bar 6, the end ring 5, and the end ring 13 form an eddy current circuit. The structural form of the eddy current circuit with different electrical characteristics makes the active current component less affected by the change of the slip rate and always maintains a sufficiently large value. Therefore, the permanent magnet composite asynchronous coupling proposed by the present invention has a small change in the electromagnetic torque within the full-slip operating range and has very hard mechanical characteristics. When the load changes, the speed fluctuation is small, which effectively overcomes the existing The shortcomings of the mechanical characteristics of the permanent magnet asynchronous coupling are too soft, which greatly improves the mechanical performance of the permanent magnet asynchronous coupling and expands its application range.

(2) The permanent magnet composite asynchronous coupling proposed by the present invention can effectively suppress the reactive current component and reduce the eddy current loss by utilizing the electrical characteristics of different eddy current circuits on the driven rotor when operating at different slip rates. Improve transmission efficiency.

(3) In the existing permanent magnet couplings, the permanent magnet poles all adopt a surface-adhesive structure, which provides a radial magnetic field, and the magnetic flux of each pole of the magnetic field is generated by only one permanent magnet pole. In the present invention, the permanent magnet pole 2 of the active rotor is located inside the iron core 3, and adopts a built-in tangential structure to provide a tangential magnetic field. The magnetic flux of each pole of the magnetic field is jointly provided by two adjacent permanent magnet poles, which can be greatly improved. The magnitude increases the magnetic flux density of the active rotor magnetic field, so the permanent magnet composite asynchronous coupling proposed by the present invention has the outstanding advantage of high power density. When transmitting the same power, the volume of the permanent magnet composite asynchronous coupling is smaller than that of the existing permanent magnet asynchronous coupling.

(4) For various existing permanent magnet couplings, the permanent magnet poles all adopt a surface-mounted structure, which cannot meet the needs of high-speed and ultra-high-speed operation. In the permanent magnet composite asynchronous coupling proposed by the present invention, in its active rotor structure, the permanent magnet pole 2 is placed in the installation groove inside the iron core 3 and fixed by gluing, and the iron core 3 is made of integral ferromagnetic material The surface is smooth, and the end cover 11 is fastened on the iron core 3 by means of screws or welding; Inside, the end cover 12 is fastened on the base 8 by means of screws or welding. Therefore, the permanent magnet composite asynchronous coupling can operate reliably under high-speed and ultra-high-speed conditions.

(4) Description of drawings

Fig. 1 Schematic diagram of the axial section of the structure of the permanent magnet composite asynchronous coupling;

Figure 2 is a schematic diagram of the radial section of the structure of the permanent magnet composite asynchronous coupling.

(5) Specific implementation methods

The present invention is described in more detail below in conjunction with accompanying drawing example:

The permanent magnet composite asynchronous shaft coupling proposed by the present invention includes three parts: a built-in tangential permanent magnet magnetic pole active rotor, a composite driven rotor, and an isolation cover.

(1) The active rotor with built-in tangential permanent magnet poles is composed of a magnetic isolation sleeve 1, a permanent magnet pole 2, an iron core 3, and an end cover 11. The magnetic isolation sleeve 1 is used to connect the output shaft of the prime mover and the driving rotor together, and at the same time, the magnetic isolation sleeve 1 also plays the role of magnetic isolation, preventing the magnetic field lines from passing through the shaft to form a loop. The permanent magnet pole 2 is made of permanent magnet material, such as NdFeB, magnetized and placed in the axial slot in the iron core 3. The magnetized direction is tangential to the circumference, that is, the magnetized direction is perpendicular to the rotor radius direction. In order to ensure the symmetry of the magnetic field, the number of permanent magnet poles 2 must be an even number, and they are evenly placed inside the core 3 along the circumferential direction. The specific number is determined by the actual design. The iron core 3 is made of solid ferromagnetic material, and its function is firstly to form the main magnetic circuit on the active rotor side, and secondly to install and fix the permanent magnet pole 2 . The iron core 3 and the magnetic isolation sleeve 1 can be fixed by means of tight fit or key connection. In order to facilitate processing and installation, the left side of the active rotor is the end cover 11, and the end cover 11 also plays the role of fixing the permanent magnet pole 2 in the axial direction. In order to prevent the magnetic flux from forming a closed circuit through the end cover 11, the end cover 11 is made of Made of magnetic material.

(2) The composite driven rotor consists of a sleeve 4, an end ring 5, an end ring 13, a guide bar 6, an iron core 7, a base 8, and an end cover 12. The sleeve 4 is made of ferromagnetic material, its magnetic permeability is lower than that of the silicon steel sheets constituting the core 7 , and the optimal value of its magnetic permeability can be obtained through electromagnetic field calculation in actual design. The iron core 7 is made of laminated silicon steel sheets to form a magnetic circuit on the side of the driven rotor. On the inner surface of the iron core 7, there are axial grooves evenly distributed along the circumference. Guide bars 6 are placed in the slots. The guide bars 6 are made of metal conductors with good electrical conductivity, such as copper bars and aluminum bars. The number of slots is the guide bar. The number of 6 depends on the specific design. The two ends of these guide bars 6 are short-circuited together by the end ring 5 and the end ring 13 respectively, and the end ring 5 and the end ring 13 are also made of metal conductors with good electrical conductivity. The axial effective length of the guide bar 6 (that is, the length between the two end rings) is equal to the axial length of the permanent magnet pole 2 in the driving rotor, and is aligned with the permanent magnet pole 2 in the axial direction. The function of the base 8 is not only to install and fix the sleeve 4, the end ring 5, the end ring 13, the guide bar 6, the iron core 7 and other components, but also the base 8 can be connected with the driven shaft by keying or tight fit. join together. In order to facilitate processing and installation, the left side of the driven rotor is an end cover 12, and the end cover 12 also plays the role of axially fixing the sleeve 4, end ring 5, end ring 13, guide bar 6, and iron core 7.

(3) The isolation cover 9 is made of non-ferromagnetic material and can be fixed on other equipment through the installation hole 10 . The isolation cover 9 can realize the space isolation between the driving shaft side and the driven shaft side, so that the coupling can meet the transmission requirements under conditions such as sealing, such as underwater propulsion and other occasions.

(4) There is an air gap 14 between the driving rotor and the isolation cover 9 , and an air gap 15 between the driven rotor and the isolation cover 9 .

(5) During operation, the rotation axes of the driving rotor and the driven rotor coincide.

Claims (1)

1. A permanent magnet composite asynchronous shaft coupling, comprising three parts of a driving rotor, a driven rotor, and an isolation cover; it is characterized in that: the driving rotor is a built-in tangential permanent magnet magnetic pole driving rotor, and the magnetic isolation shaft sleeve (1), permanent magnet pole (2), and the first iron core (3), the magnetic isolation sleeve (1) is used to connect the output shaft of the prime mover, and the first iron core (3) is made of solid ferromagnetic material The first iron core (3) is fixed between the magnetic isolation sleeve (1), and the permanent magnetic pole (2) is made of permanent magnetic material, and is placed in the axial groove in the first iron core (3); The driven rotor is a composite driven rotor, which consists of a sleeve (4), a first end ring (5), a second end ring (13), a guide bar (6), a second iron core (7), a base The seat (8), the second end cover (12), the sleeve (4) is made of ferromagnetic material, the second iron core (7) is made of laminated silicon steel sheets, on the inner surface of the second iron core (7) There are axial grooves evenly distributed along the circumference, and guide bars (6) are placed in the grooves. The guide bars (6) are made of metal conductors with good electrical conductivity, and the two ends of each guide bar (6) pass through the first end ring respectively. (5) and the second end ring (13) are short-circuited together, the first end ring (5) and the second end ring (13) are also made of metal conductors with good electrical conductivity, the sleeve (4), the first The end ring (5), the second end ring (13), the guide bar (6) and the second iron core (7) are fixed by the base (8), and the base (8) is used to connect with the driven shaft; isolation The cover (9) is made of non-ferromagnetic material and fixed on other equipment through the installation hole (10); there is a first air gap (14) between the active rotor and the isolation cover (9), and the first air gap (14) between the driven rotor and the isolation cover Between (9) is the second air gap (15); The magnetization direction of the first iron core (3) is the tangential direction of the circumference, that is, the magnetization direction is perpendicular to the radial direction of the rotor, and the number of permanent magnet poles (2) is an even number, and inside the first iron core (3) Evenly placed along the circumferential direction, two adjacent permanent magnet poles face the same polarity surface; A first end cover (11) is arranged on the left side of the driving rotor, and the first end cover (11) is made of a non-magnetic material; The magnetic permeability of the sleeve (4) is lower than that of the silicon steel sheet forming the second iron core (7); The axial effective length of the guide bar (6) in the composite driven rotor, that is, the length between the two end rings is equal to the axial length of the permanent magnet pole (2) in the driving rotor, and is equal to the permanent magnet pole (2) ) are axially aligned; A second end cover (12) is arranged on the left side of the driven rotor.

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