Torque motor

Abstract

The invention relates to a torque motor which comprises a stator and a rotor which are separated by a single-layer air gap. The stator comprises a stator iron core, a stator concentrated winding and stator permanent magnets, the stator iron core is composed of stator teeth and a stator yoke, the stator concentrated winding is wound on the stator teeth, and a plurality of stator permanent magnets are embedded in the surface, close to the single-layer air gap, of each stator tooth; the rotor comprises a rotor iron core, a rotor concentrated winding and rotor permanent magnets, the rotor iron core is composed of rotor teeth and a rotor yoke, the rotor concentrated winding is wound on the rotor teeth, and a plurality of rotor permanent magnets are embedded in the surface, close to the single-layer air gap, of each rotor tooth; the magnetizing directions of all the stator permanent magnets are the same, and the magnetizing directions of all the rotor permanent magnets are the same. The number of pole pairs of the permanent magnets of the torque motor is large, the magnetic field modulation effect can be fully utilized to generate torque, the magnetic pole structure of the consequent poles can reduce the number of the permanent magnets, the concentrated winding is adopted to reduce the loss and volume of the end winding, and the torque density and the permanent magnet utilization rate are improved.

Description

Technical Field

[0001] The present invention relates to the field of motors, and particularly to a torque motor. Background Art

[0002] Compared with the traditional drive scheme with a speed-changing gearbox, the direct drive technology can eliminate the intermediate transmission mechanism, directly connect the moving parts and the motor rotor, improve the control accuracy and dynamic response, and has broad application prospects. In some application scenarios such as high-end numerical control machine tools and flight test platforms, a type of direct drive turntable motor is required to drive the platform to rotate precisely and slowly. This requires the motor to have the output characteristics of low speed and high torque. At the same time, to reduce the volume of the entire platform, the motor needs to have a flat structure with a larger diameter and a shorter axial length. However, since the direct drive motor does not have a reduction gearbox and cannot obtain the torque amplification gain brought by the gearbox, the motor output torque is the platform drive torque. As the requirements for the drive torque in the above application scenarios are getting higher and higher, the torque density of the direct drive motor needs to be further improved to adapt to the industry development.

[0003] In the existing improved motor design scheme, a set of permanent magnets and a set of armature windings are respectively arranged on the stator and the rotor to increase the torque density of the motor. For example, the invention patent with the publication number of CN111463939A discloses a magnetic field modulation permanent magnet motor with double permanent magnets and double armature windings on the stator and rotor, including a stator and a rotor both of which are salient pole structures, the rotor and the stator rotate relative to each other, an annular air gap is formed between the stator and the rotor, the rotor includes a rotor core, a rotor armature winding and a rotor permanent magnet, the rotor core includes rotor teeth and a rotor yoke, the rotor armature winding is a two-phase armature winding wound on the rotor teeth, the rotor permanent magnet is arranged in the slot between two rotor teeth, the stator includes a stator core, a stator armature winding and a stator permanent magnet, the stator core includes stator teeth and a stator yoke, the stator armature winding is a three-phase armature winding wound on the stator teeth, and the stator permanent magnet is arranged in the slot between two stator teeth.

[0004] The above-mentioned stator-rotor dual permanent magnet dual armature winding magnetic field modulation permanent magnet motor has two sets of permanent magnets and two sets of armature windings, which effectively improves the electrical load and magnetic load of the motor and increases the output torque of the motor. At the same time, although the rotor armature winding needs to be powered by brushes and slip rings, the speed of the turntable motor is low, and the introduction of brushes and slip rings has little effect on the life of the motor. However, the number of stator permanent magnet pole pairs (the number of repeated periods of the permanent magnet arrangement on the circumference) of the motor is equal to the number of stator teeth, and the number of rotor permanent magnet pole pairs is equal to the number of rotor teeth. The formula for calculating the pitch coefficient of the stator armature winding is cos[(360°÷number of stator teeth×number of rotor permanent magnet pole pairs×winding coil span+180°)÷2], and the formula for calculating the pitch coefficient of the rotor armature winding is cos[(360°÷number of rotor teeth×number of stator permanent magnet pole pairs×winding coil span+180°)÷2], where winding coil span = 1 indicates concentrated winding, and winding coil span > 1 indicates distributed winding. In this case, in order to obtain a larger winding pitch coefficient to increase the motor torque, both the stator armature winding and the rotor armature winding need to adopt a distributed winding structure, and the winding coil span > 3, which will result in a large amount of cross-overlap at the ends of each winding coil. For flat structure motors such as turntable motors, the use of distributed windings will significantly increase the end size and loss of the motor, thereby reducing the torque density of the motor. The invention patent with publication number CN118646189A discloses a frame servo motor, which also has a similar problem and is not suitable for the application of turntable motors.

[0005] Among the existing schemes aimed at improving torque density, there are also motor design schemes using concentrated windings. For example, the invention patent with publication number CN110112852A discloses a doubly-fed permanent magnet motor, including a primary and a secondary both of which are salient pole structures, wherein the primary includes a primary iron core, a bipolar permanent magnet and a primary winding, the primary iron core includes primary iron core teeth and a primary iron core yoke, the primary winding is arranged in a primary iron core slot formed between the primary iron core teeth, the bipolar permanent magnet is arranged between the primary iron core teeth of two adjacent primary iron core blocks, the secondary iron core includes secondary iron core teeth and a secondary iron core yoke, and the secondary winding is arranged in a secondary iron core slot formed between the secondary iron core teeth.

[0006] The stator and rotor armature windings of the above-mentioned doubly-fed permanent magnet motor can both adopt the form of concentrated windings to avoid the problem of oversized motor ends. At the same time, the design of two sets of armature windings can increase the electrical load of the motor. However, the motor has only one set of stator bipolar permanent magnets, and the number of pole pairs of the permanent magnets is small, which cannot fully utilize the magnetic field modulation effect to generate electromagnetic torque. At the same time, the amount of permanent magnets used is large, resulting in the motor's torque density and permanent magnet utilization rate (average torque ÷ amount of permanent magnets used) being lower than traditional motors. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a torque motor, which can reduce the end losses and size of the motor, reduce the amount of permanent magnets used, and ultimately improve the torque density and utilization rate of permanent magnets of the motor while increasing the electrical load and magnetic load of the motor.

[0008] The technical solution adopted by the present invention is a torque motor, which includes a stator and a rotor. The stator and the rotor are separated by a single-layer air gap. The stator includes a stator core, a stator concentrated winding, and a stator permanent magnet. The stator core is composed of stator teeth and a stator yoke. The stator concentrated windings are respectively wound on each stator tooth, and the current in the stator concentrated windings is polyphase alternating current. The stator permanent magnets are embedded in the surface of the stator teeth close to the single-layer air gap. The number Npms of the stator permanent magnets satisfies: Npms = ks × Ns; where Ns is the number of stator teeth, and ks is an integer greater than 1. The rotor includes a rotor core, a rotor concentrated winding, and a rotor permanent magnet. The rotor core is composed of rotor teeth and a rotor yoke. The rotor concentrated windings are respectively wound on each rotor tooth, and the current in the rotor concentrated windings is polyphase alternating current. The rotor permanent magnets are embedded in the surface of the rotor teeth close to the single-layer air gap. The number of the rotor permanent magnets satisfies Npmr = kr × Nr, where Nr is the number of rotor teeth, and kr is an integer greater than 1. The magnetization directions of all the stator permanent magnets are the same. The magnetization directions of all the rotor permanent magnets are the same.

[0009] The beneficial effects of the present invention are as follows: The above torque motor has two sets of permanent magnets and two sets of armature windings, which helps to increase the magnetic load and electrical load of the motor, and thus increases the electromagnetic torque of the motor. And, since the magnetization directions of all the stator permanent magnets are the same, the number of pole pairs of the stator permanent magnets is equal to the number of stator permanent magnets (the same is true for the rotor permanent magnets). On this premise, by adjusting the multiple (i.e., ks) between the number of stator permanent magnets and the number of stator teeth and the multiple (i.e., kr) between the number of rotor permanent magnets and the number of rotor teeth, the pitch factor of the motor winding can be changed, so that the motor still has a high pitch factor when using the stator concentrated winding and the rotor concentrated winding, ensuring the output torque while reducing the end winding losses and size, and achieving the purpose of increasing the torque density of the motor. In addition, since the number of stator permanent magnets and rotor permanent magnets of the above torque motor is much higher than that of the existing motors, the magnetic field modulation effect can be more fully utilized to generate electromagnetic torque, and at the same time, the magnetic pole structure of the alternating poles (i.e., the magnetization directions of all the stator permanent magnets are the same, and the magnetization directions of all the rotor permanent magnets are the same) helps to greatly reduce the amount of permanent magnets used and achieve the purpose of increasing the utilization rate of the permanent magnets of the motor.

[0010] Preferably, the magnetization direction of the stator permanent magnet is the same as that of the rotor permanent magnet; with this structure, the stator permanent magnetic field and the rotor permanent magnetic field are in series, which helps to increase the magnetomotive force of the main magnetic circuit and thus improve the torque density of the motor.

[0011] Preferably, the magnetization direction of the stator permanent magnet is opposite to that of the rotor permanent magnet; with this structure, the stator permanent magnetic field forms a closed loop through the rotor teeth, and the rotor permanent magnetic field forms a closed loop through the stator teeth. The two magnetic paths can produce a superimposed effect, increasing the magnetomotive force and magnetic flux of the main magnetic circuit, and thus improving the torque density of the motor.

[0012] Preferably, the ks and the kr are equal. In this case, the current frequencies in the stator concentrated winding and the rotor concentrated winding are relatively close, and the hardware requirements for the two windings on the converter are relatively similar. The same specification converter can be used for power supply, reducing the adaptation cost of the converter.

[0013] Preferably, the ks and the kr are not equal. In this case, the winding coefficients of the two windings can be adjusted more flexibly, so that the stator winding and the rotor winding can simultaneously have higher winding coefficients, thereby improving the torque density of the motor.

[0014] Preferably, the Ns is a multiple of 8, and the Nr is a multiple of 9. In this case, the stator winding is a two-phase winding, and the rotor winding is a three-phase winding, so that both windings can be powered by the most common three-phase full-bridge converter, thus reducing the adaptation cost of the converter.

[0015] Preferably, the Ns is a multiple of 9, and the Nr is a multiple of 8. In this case, the stator winding is a three-phase winding, and the rotor winding is a two-phase winding, so that both windings can be powered by the most common three-phase full-bridge converter, thus reducing the adaptation cost of the converter.

[0016] Preferably, the stator is located outside the rotor. With this structure, the motor rotor can be connected to the platform rotating shaft to drive the platform to rotate, which is suitable for the occasion where the platform moving part is a slender rotating shaft.

[0017] Preferably, the stator is located inside the rotor. With this structure, the motor rotor can be sleeved inside the platform hub to drive the platform to rotate, which is suitable for the occasion where the platform moving part is a flat hub.

[0018] Preferably, both the stator and the rotor are of linear structure. With this structure, the torque motor can be applied to the occasion of linear motion. Description of the Drawings

[0019] Figure 1 Schematic structural diagram of a torque motor described in Embodiment 1 of the present invention; Figure 2 Schematic structural diagram of a torque motor described in Embodiment 2 of the present invention; Figure 3 Schematic structural diagram of a torque motor described in Embodiment 3 of the present invention; Figure 4 Schematic structural diagram of a doubly-fed permanent magnet motor of the prior art used in three-dimensional finite element simulation calculation of electromagnetic field; Figure 5 Schematic diagram of torque waveforms of the doubly-fed permanent magnet motor of the prior art and the torque motor of Embodiment 3 in three-dimensional finite element simulation calculation of electromagnetic field; Figure 6 Schematic diagram of performance comparison between the motor of Embodiment 3 of the present invention and the doubly-fed permanent magnet motor of the prior art; As shown in the figure: 1. Stator; 2. Rotor; 3. Single-layer air gap; 11. Stator core; 12. Stator concentrated winding; 13. Stator permanent magnet; 111. Stator tooth; 112. Stator yoke; 21. Rotor core; 22. Rotor concentrated winding; 23. Rotor permanent magnet; 211. Rotor tooth; 212. Rotor yoke. Detailed implementation manners

[0020] The following further describes the invention with reference to the accompanying drawings and in combination with specific implementation manners, so that those skilled in the art can implement it according to the text of the specification. The protection scope of the present invention is not limited to this specific implementation manner.

[0021] Those skilled in the art should understand that in the disclosure of the present invention, the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting the present invention.

[0022] In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0023] In the description of the embodiments of the present application, it should also be noted that, unless otherwise clearly specified and limited, the terms "arrangement", "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0024] Embodiment 1: The present invention relates to a torque motor, as Figure 1 shown, which includes a stator 1 and a rotor 2. The stator 1 and the rotor 2 are separated by a single-layer air gap 3. The stator 1 includes a stator core 11, a stator concentrated winding 12, and a stator permanent magnet 13; the stator core 11 is composed of stator teeth 111 and a stator yoke 112; the stator concentrated winding 12 is wound around each stator tooth 111, and the current in the stator concentrated winding 12 is polyphase alternating current; the stator permanent magnet 13 is embedded in the surface of the stator tooth 111 close to the single-layer air gap 3; the number of stator teeth 111 is Ns = 8, and the number of stator permanent magnets 13 is Npms = 24, satisfying Npms = ks × Ns, where ks is an integer greater than 1 (value = 3); the rotor 2 includes a rotor core 21, a rotor concentrated winding 22, and a rotor permanent magnet 23; the rotor core 21 is composed of rotor teeth 211 and a rotor yoke 212; the rotor concentrated winding 22 is wound around each rotor tooth 211, and the current in the rotor concentrated winding 22 is polyphase alternating current; the rotor permanent magnet 23 is embedded in the surface of the rotor tooth 211 close to the single-layer air gap 3; the number of rotor teeth 211 is Nr = 9, and the number of rotor permanent magnets 23 is Npmr = 27, satisfying Npmr = kr × Nr, where kr is an integer greater than 1 (value = 3); the magnetization directions of all the stator permanent magnets 13 are the same; the magnetization directions of all the rotor permanent magnets 23 are the same.

[0025] Figure 1The torque motor therein has two sets of permanent magnets and two sets of armature windings, which helps to increase the magnetic load and electric load of the motor, thereby increasing the electromagnetic torque of the motor. Moreover, the magnetization directions of all the stator permanent magnets are the same. Therefore, the number of stator permanent magnet pole pairs is equal to the number of stator permanent magnets (the same applies to the rotor permanent magnets). On this premise, there is a multiple relationship between the number of stator permanent magnets and the number of stator teeth, and there is a multiple relationship between the number of rotor permanent magnets and the number of rotor teeth. In this way, the pitch factor of the motor winding can be changed by changing the multiple, so that when the stator concentrated winding and the rotor concentrated winding are adopted, the motor still has a high pitch factor, ensuring the output torque while reducing the end winding loss and size, achieving the purpose of increasing the torque density of the motor. Since the number of stator permanent magnets and the number of rotor permanent magnets of this torque motor are much higher than those of existing motors, the magnetic field modulation effect can be more fully utilized to generate electromagnetic torque. At the same time, the magnetic pole structure of the alternating poles (that is, the magnetization directions of all the stator permanent magnets are the same, and the magnetization directions of all the rotor permanent magnets are the same) helps to significantly reduce the amount of permanent magnets used, achieving the purpose of increasing the utilization rate of the permanent magnets of the motor.

[0026] As Figure 1 shown, the magnetization directions of the stator permanent magnet 13 and the rotor permanent magnet 23 are also the same, making the stator permanent magnetic field and the rotor permanent magnetic field in series, which helps to increase the magnetomotive force of the main magnetic circuit, thereby increasing the torque density of the motor.

[0027] As Figure 1 shown, ks = kr = 3, making the current frequencies in the stator concentrated winding and the rotor concentrated winding relatively close, and the hardware requirements for the two windings on the converter are relatively similar. The same specification of converter can be used for power supply, reducing the adaptation cost of the converter.

[0028] As Figure 1 shown, Ns = 8, which is a multiple of 8, and Nr = 9, which is a multiple of 9. Then the stator concentrated winding 12 is a two-phase winding, and the rotor concentrated winding 22 is a three-phase winding, making both windings can be powered by the most common three-phase full-bridge converter, thus reducing the adaptation cost of the converter.

[0029] As Figure 1 shown, the stator 1 is located outside the rotor 2, and the rotor 2 is used to internally connect the rotating shaft of the driving platform. This motor structure is suitable for the occasion where the platform moving part is a slender rotating shaft.

[0030] Embodiment 2: The present invention relates to a torque motor, as Figure 2As shown in the figure, it includes a stator 1 and a rotor 2, and the stator 1 and the rotor 2 are separated by a single-layer air gap 3. The stator 1 includes a stator core 11, a stator concentrated winding 12 and a stator permanent magnet 13; the stator core 11 is composed of stator teeth 111 and a stator yoke 112; the stator concentrated winding 12 is wound around each stator tooth 111, and the current in the stator concentrated winding 12 is polyphase alternating current; the stator permanent magnet 13 is embedded on the surface of the stator tooth 111 close to the single-layer air gap 3; the number of stator teeth 111 is Ns = 9, and the number of stator permanent magnets 13 is Npms = 27, satisfying Npms = ks × Ns, where ks is an integer greater than 1 (value = 3); the rotor 2 includes a rotor core 21, a rotor concentrated winding 22 and a rotor permanent magnet 23; the rotor core 21 is composed of rotor teeth 211 and a rotor yoke 212; the rotor concentrated winding 22 is wound around each rotor tooth 211, and the current in the rotor concentrated winding 22 is polyphase alternating current; the rotor permanent magnet 23 is embedded on the surface of the rotor tooth 211 close to the single-layer air gap 3; the number of rotor teeth 211 is Nr = 8, and the number of rotor permanent magnets 23 is Npmr = 24, satisfying Npmr = kr × Nr, where kr is an integer greater than 1 (value = 3); the magnetization directions of the stator permanent magnets 13 are all the same; the magnetization directions of the rotor permanent magnets 23 are all the same.

[0031] As Figure 2 shown, the magnetization direction of the stator permanent magnet 13 is opposite to that of the rotor permanent magnet 23, so that the magnetic field of the stator permanent magnet 13 forms a closed loop through the rotor tooth 211, and the magnetic field of the rotor permanent magnet 23 forms a closed loop through the stator tooth 111, thereby causing the two magnetic paths to produce a superimposed effect, increasing the magnetomotive force and magnetic flux of the main magnetic path (the magnetic path passing through the stator core 11, the single-layer air gap 3 and the rotor core 21 completely), and further improving the torque density of the motor.

[0032] As Figure 2 shown, ks = kr = 3, so that the current frequencies in the stator concentrated winding and the rotor concentrated winding are relatively close, and the hardware requirements for the two windings for the converter are relatively similar. The same specification of converter can be used for power supply, reducing the adaptation cost of the converter.

[0033] As Figure 2 shown, Ns = 9, which is a multiple of 9, while Nr = 8, which is a multiple of 8. The stator concentrated winding 12 is a three-phase winding, and the rotor concentrated winding 22 is a two-phase winding, so that both windings can be powered by the most common three-phase full-bridge converter, thereby reducing the adaptation cost of the converter.

[0034] As Figure 2 shown, the stator 1 is located inside the rotor 2, and the rotor 2 is used for the hub of the external drive platform. This motor structure is applicable to the occasion where the platform moving part is a flat hub.

[0035] Embodiment 3: The present invention relates to a torque motor, as Figure 3 shown, which includes a stator 1 and a rotor 2. The stator 1 and the rotor 2 are separated by a single-layer air gap 3. The stator 1 includes a stator core 11, a stator concentrated winding 12, and a stator permanent magnet 13. The stator core 11 is composed of stator teeth 111 and a stator yoke 112. The stator concentrated winding 12 is wound around each stator tooth 111, and the current in the stator concentrated winding 12 is polyphase alternating current. The stator permanent magnet 13 is embedded in the surface of the stator tooth 111 close to the single-layer air gap 3. The number of stator teeth 111 is Ns = 8, and the number of stator permanent magnets 13 is Npms = 32, satisfying Npms = ks × Ns, where ks is an integer greater than 1 (value = 4). The rotor 2 includes a rotor core 21, a rotor concentrated winding 22, and a rotor permanent magnet 23. The rotor core 21 is composed of rotor teeth 211 and a rotor yoke 212. The rotor concentrated winding 22 is wound around each rotor tooth 211, and the current in the rotor concentrated winding 22 is polyphase alternating current. The rotor permanent magnet 23 is embedded in the surface of the rotor tooth 211 close to the single-layer air gap 3. The number of rotor teeth 211 is Nr = 9, and the number of rotor permanent magnets 23 is denoted as Npmr = 27, satisfying Npmr = kr × Nr, where kr is an integer greater than 1 (value = 3). The magnetization directions of the stator permanent magnets 13 are all the same. The magnetization directions of the rotor permanent magnets 23 are all the same.

[0036] As Figure 3 shown, the magnetization directions of the stator permanent magnets 13 and the rotor permanent magnets 23 are also the same, so that the stator permanent magnetic field and the rotor permanent magnetic field are in series, which helps to increase the magnetomotive force of the main magnetic circuit and thus improve the torque density of the motor.

[0037] As Figure 3 shown, ks ≠ kr, which can more flexibly adjust the winding coefficients of the two sets of windings, so that the stator concentrated winding 12 and the rotor concentrated winding 22 can simultaneously have higher winding coefficients, thereby improving the torque density of the motor. In this embodiment, the pitch factor of the stator concentrated winding 12 is 0.92, and the pitch factor of the rotor concentrated winding 22 is 0.98.

[0038] As Figure 3 shown, Ns = 8, which is a multiple of 8, and Nr = 9, which is a multiple of 9. The stator concentrated winding 12 is a two-phase winding, and the rotor concentrated winding 22 is a three-phase winding, so that both sets of windings can be powered by the most common three-phase full-bridge converter, thereby reducing the adaptation cost of the converter.

[0039] As Figure 3 shown, the stator 1 is located outside the rotor 2, and the rotor 2 can be internally connected to the rotating shaft of the driving platform. This motor structure is suitable for the occasion where the platform moving part is a slender rotating shaft.

[0040] The advantages of a torque motor according to the present invention are illustrated below by comparison with a doubly-fed permanent magnet motor in the prior art. The data are obtained through three-dimensional finite element simulation of the electromagnetic field and actual measurement of the performance of a prototype.

[0041] In the three-dimensional finite element simulation of the electromagnetic field, the outer diameter of the doubly-fed permanent magnet motor in the prior art used is 100 mm, the axial length is 50 mm, the winding loss is 20 W. The simulation model includes the end windings of the motor and the air region within 50 mm outside the motor to fully evaluate the influence of the magnetic leakage of the motor on the torque performance. A tetrahedral pyramid mesh is used for finite element meshing, the maximum side length of the mesh is set to 5 mm, and a double-layer mesh is used for meshing at the air gap. The number of meshes in the entire model is approximately 1.3 million. The torque waveform diagram of the doubly-fed permanent magnet motor obtained by simulation is as Figure 5 shown; similarly, for a torque motor described in Embodiment 3 used, the outer diameter is 100 mm, the axial length is 50 mm, and the winding loss is 20 W. The simulation model includes the end windings of the motor and the air region within 50 mm outside the motor to fully evaluate the influence of the magnetic leakage of the motor on the torque performance. A tetrahedral pyramid mesh is used for finite element meshing, the maximum side length of the mesh is set to 5 mm, and a double-layer mesh is used for meshing at the air gap. The number of meshes in the entire model is approximately 1.3 million. The torque waveform diagram obtained by simulation is as Figure 5 shown. It can be seen from Figure 5 that for a torque motor described in Embodiment 3, the average torque is 5.51 N·m and the permanent magnet volume is 31.7 cm³, while for the doubly-fed permanent magnet motor in the prior art, the average torque is 4.34 N·m and the permanent magnet volume is 51.1 cm³. It can be obtained that as Figure 6 shown, taking the doubly-fed permanent magnet motor in the prior art as the comparison object, when a torque motor described in Embodiment 3 and the doubly-fed permanent magnet motor have the same outer dimensions and losses of the motor, the average torque of the torque motor described in Embodiment 3 is 27% higher than that of the doubly-fed permanent magnet motor in the prior art, and the permanent magnet volume of the torque motor described in Embodiment 3 is 38% lower than that of the doubly-fed permanent magnet motor in the prior art, making the utilization rate of the permanent magnet (average torque ÷ permanent magnet volume) of the torque motor described in Embodiment 3 105% higher than that of the doubly-fed permanent magnet motor in the prior art.

[0042] A torque motor described in Embodiment 3 is made into an actual prototype, whose size is exactly the same as the motor model in the three-dimensional finite element simulation calculation of the electromagnetic field. The torque motor prototype is connected to a standard servo motor through a torque sensor. The same rated current is applied to the torque motor using a hardware-in-the-loop simulation platform, and the winding voltage, current, speed, and torque information of the torque motor are collected through an oscilloscope and a torque sensor. By adjusting the current in the torque motor and the load torque provided by the servo motor, the torque performance of the torque motor under different currents is obtained. The experimental results are compared with the results of the three-dimensional finite element simulation calculation of the electromagnetic field, and it is found that the data are in agreement, which can verify the correctness and effectiveness of the results of the three-dimensional finite element simulation calculation of the electromagnetic field.

Claims

1. A torque motor, comprising a stator (1) and a rotor (2), the stator (1) and the rotor (2) being separated by a single-layer air gap (3); characterized in that: The stator (1) includes a stator core (11), a stator concentrated winding (12), and a stator permanent magnet (13); the stator core (11) is composed of stator teeth (111) and a stator yoke (112); the stator concentrated winding (12) is wound around each stator tooth (111), and the current in the stator concentrated winding (12) is polyphase alternating current; the stator permanent magnet (13) is embedded in the surface of the stator tooth (111) close to the single-layer air gap (3); the number Npms of the stator permanent magnets (13) satisfies: Npms = ks × Ns; where Ns is the number of stator teeth (111), and ks is an integer greater than 1; the rotor (2) includes a rotor core (21), a rotor concentrated winding (22), and a rotor permanent magnet (23); the rotor core (21) is composed of rotor teeth (211) and a rotor yoke (212); the rotor concentrated winding (22) is wound around each rotor tooth (211), and the current in the rotor concentrated winding (22) is polyphase alternating current; the rotor permanent magnet (23) is embedded in the surface of the rotor tooth (211) close to the single-layer air gap (3); the number of the rotor permanent magnets (23) satisfies Npmr = kr × Nr, where Nr is the number of rotor teeth (211), and kr is an integer greater than 1; the magnetization directions of the stator permanent magnets (13) are all the same; the magnetization directions of the rotor permanent magnets (23) are all the same.

2. The torque motor according to claim 1, characterized in that: The magnetization direction of the stator permanent magnet (13) is the same as that of the rotor permanent magnet (23).

3. A torque motor according to claim 1, characterized in that: The magnetization direction of the stator permanent magnet (13) is opposite to that of the rotor permanent magnet (23).

4. A torque motor according to claim 1 or 2 or 3, characterized in that: The ks and the kr are equal.

5. A torque motor according to claim 1 or 2 or 3, characterized in that: The ks and the kr are not equal.

6. A torque motor according to claim 1 or 2 or 3, characterized in that: The Ns is a multiple of 8, and the Nr is a multiple of 9.

7. A torque motor according to claim 1 or 2 or 3, characterized in that: The Ns is a multiple of 9, and the Nr is a multiple of 8.

8. A torque motor according to claim 1, wherein: The stator (1) is located outside the rotor (2).

9. A torque motor according to claim 1, characterized in that: The stator (1) is located inside the rotor (2).

10. A torque motor according to claim 1, characterized in that: The stator (1) and the rotor (2) are both of linear structures.

Images