A claw-pole magnetic levitation torque motor based on an auxiliary slot and its design method

Abstract

A claw-pole magnetic levitation torque motor based on an auxiliary slot and its design method are disclosed. The motor includes a stator assembly and a rotor assembly. The rotor assembly includes a rotor core and permanent magnets. The permanent magnets are circumferentially and uniformly distributed on the outer circumferential surface of the rotor core. The permanent magnets are magnetized radially, with adjacent permanent magnets magnetized in opposite directions. The stator assembly includes claw poles, a coil frame, coils, and a housing. The claw poles include upper and lower claw poles arranged axially opposite each other. Each claw pole has multiple claw pole teeth on its opposite surface, which are evenly spaced circumferentially, forming a tooth groove between adjacent claw pole teeth. The upper and lower claw poles close together, with the claw pole teeth of one claw pole inserting into the tooth groove of the other claw pole, thus surrounding the rotor assembly. This invention utilizes the circumferential restoring torque between the stator assembly and the rotor assembly for zero-point positioning, eliminating the need for mechanical springs. Each claw pole tooth 120 is provided with an auxiliary slot 110 to enhance the circumferential restoring torque.

Description

Technical Field

[0001] This invention relates to a claw-pole magnetic levitation torque motor based on an auxiliary slot and its design method. Background Technology

[0002] Hydraulic systems are among the most common energy conversion and transmission systems in industry, and electro-hydraulic directional valves are key fundamental components. As the bridge connecting the electrical and hydraulic parts of the electro-hydraulic directional valve, the electro-mechanical converter plays a decisive role in its performance. The claw-pole magnetic levitation torque motor is a valve electro-mechanical converter that utilizes the magnetic force between the stator and rotor for zero-point positioning and power-off reset. Although the claw-pole magnetic levitation torque motor has advantages such as simple structure, large output angular displacement, convenient zero-point positioning, and high power-to-weight ratio, its zero-point positioning suffers from significant errors due to insufficient stiffness of the circumferential positive magnetic spring at the zero point. Summary of the Invention

[0003] The present invention aims to overcome the above-mentioned shortcomings of the prior art and provides a claw-pole magnetic levitation torque motor based on an auxiliary slot and its design method.

[0004] The first aspect of the present invention is to provide a claw-pole magnetic levitation torque motor based on an auxiliary slot, wherein the zero-point circumferential positive magnetic spring has high stiffness and accurate zero-point positioning.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A claw-pole magnetic levitation torque motor based on an auxiliary slot, comprising a stator assembly and a rotor assembly;

[0007] The rotor assembly consists of a rotor core and permanent magnets;

[0008] The rotor core is fixed to external components through the rotor connection port, and outputs torque and angular displacement outward; permanent magnets are evenly distributed on the outer circumferential surface of the rotor core; the magnetization direction of the permanent magnets is radial, and the magnetization direction of adjacent permanent magnets is opposite.

[0009] The stator assembly consists of two claw poles, a coil frame, coils, and a housing;

[0010] Coils are distributed on the coil frame; the claw poles and coil frame are fixedly connected to the outer shell, and the outer shell is fixedly connected to external components through the outer shell threaded holes; the claw poles include upper claw poles and lower claw poles arranged opposite each other along the axial direction, each claw pole has multiple claw pole teeth on its opposite surface, the claw pole teeth are evenly spaced along the circumference, and a tooth groove is formed between two adjacent claw pole teeth; the upper claw poles and lower claw poles close up and down, the claw pole teeth of the claw poles are inserted into the tooth grooves of the other claw poles, and the upper claw pole teeth and lower claw pole teeth surround the rotor assembly;

[0011] Each claw tooth is provided with an auxiliary groove; the auxiliary groove is located on the center line of the claw tooth, so that the claw tooth is symmetrical about the auxiliary groove; the auxiliary groove extends along the axial direction of the claw tooth and thus runs through the entire claw tooth.

[0012] Preferably, the permanent magnet can be rectangular or tile-shaped;

[0013] Preferably, the pole arc coefficient of the rotor assembly is 0.8-1;

[0014] The number of claw teeth can be arbitrary, as long as it is greater than 2;

[0015] Preferably, the claw teeth can be trapezoidal or rectangular;

[0016] Preferably, the number of permanent magnets is equal to the number of claw pole teeth;

[0017] Preferably, two sets of coils are used;

[0018] When the rotor assembly is in the zero position, each permanent magnet is directly opposite two claw pole teeth, and the areas of the opposite pole teeth are equal.

[0019] This torque motor utilizes the circumferential restoring torque between the stator and rotor assemblies for zero-point positioning, eliminating the need for mechanical springs.

[0020] To achieve precise positioning of the claw-pole magnetic levitation torque motor at zero point and improve the stiffness of the circumferential positive magnetic spring at zero point, a second aspect of the present invention is to provide a method for improving the stiffness of the circumferential positive magnetic spring of the claw-pole magnetic levitation torque motor based on an auxiliary slot.

[0021] To achieve this object, the present invention adopts the following technical solutions:

[0022] A design method for a claw-pole magnetic levitation torque motor based on an auxiliary slot, wherein the positive magnetic spring torque is the magnetic torque used for zero-point positioning and power-off reset between the stator and rotor assemblies of the claw-pole magnetic levitation torque motor, includes the following steps:

[0023] S1: Determine the basic structural parameters of the torque motor;

[0024] According to the design requirements, determine the outer diameter Rr of the permanent magnet, the inner diameter Rs1 of the claw pole teeth, the outer diameter Rs2 of the claw pole teeth, the thickness Lp of the permanent magnet, the height Hp of the permanent magnet, the width Wp of the permanent magnet, the number N of the permanent magnet and claw pole teeth, the maximum single-sided axial working stroke Y of the torque motor, and the working air gap g of the torque motor.

[0025] S2: Determine the initial dimensions of the claw pole teeth;

[0026] The method for determining the initial dimensions of the claw pole teeth includes: the recommended range for the claw pole tooth height Hc is as follows: The recommended range for the claw tooth inclination angle α is 65° ≤ α ≤ 85°, and the recommended range for the claw tooth spacing is t > 1 mm.

[0027] S3: Calculate the circumferential restoring torque and electromagnetic torque;

[0028] A finite element simulation model was constructed to calculate the restoring torque at different angular displacements and the electromagnetic torque at zero position at different excitation currents, and the angular displacement-restoring torque curve was plotted. The gain of the angular displacement-restoring torque curve at each position is the circumferential positive magnetic spring stiffness at that position. If the zero-point gain is negative, it indicates that the torque motor has circumferential positive magnetic spring stiffness.

[0029] S4: Optimize electromagnetic torque;

[0030] While ensuring the torque motor has circumferential positive magnetic spring stiffness, an optimization design method is adopted, with electromagnetic torque as the optimization target. Within the suggested value range described in step S2, the claw pole tooth height Hc, claw pole tooth tilt angle α, and claw pole tooth spacing t are used as adjustable parameters for simulation analysis. The optimal claw pole tooth height Hc, claw pole tooth tilt angle α, and claw pole tooth spacing t are then selected.

[0031] S5: Open an auxiliary groove on the center line of the claw pole teeth and determine the initial size;

[0032] Based on the optimal design parameters selected in step S4, a 3D model of the torque motor is drawn, and an auxiliary groove is created on the center line of the claw pole teeth. The initial dimensions of the auxiliary groove are determined as follows: the suggested range for the auxiliary groove width Wa is g ≤ W. a For tanks ≤2t, the recommended value range for the auxiliary tank depth Da is D. a ≤g;

[0033] S6: Calculate the circumferential restoring torque and electromagnetic torque, and optimize the circumferential restoring torque;

[0034] A finite element simulation model was constructed to calculate the restoring torque at different angular displacements and the electromagnetic torque at zero position under different excitation currents. An optimization design method was adopted, with the positive circumferential magnetic spring stiffness at zero point as the optimization objective. Within the suggested value range described in S5, the auxiliary slot width Wa and auxiliary slot depth Da were used as adjustable parameters for simulation analysis. The optimal auxiliary slot width Wa and auxiliary slot depth Da were then selected.

[0035] The working principle of this invention is:

[0036] When the claw-pole magnetic levitation torque motor is not powered, it uses the circumferential restoring torque between the claw teeth and the permanent magnet for zero-point positioning, eliminating the need for a zero-adjustment spring. The circumferential restoring torque of the claw-pole magnetic levitation torque motor changes due to the relative displacement between the stator and rotor, functioning similarly to and similarly to a spring; therefore, the claw-pole magnetic levitation torque motor is said to possess a circumferential positive magnetic spring. The gain of the circumferential restoring torque is called the circumferential positive magnetic spring stiffness.

[0037] The circumferential restoring torque of a claw-pole magnetic levitation torque motor is caused by the tangential component of the interaction force between the permanent magnet and the claw pole slots. This restoring torque still exists when the coil is not energized. This force always attempts to align the centerline of the permanent magnet with the centerline of the slot between the two claw pole teeth. Since most of the energy change in the claw-pole magnetic levitation torque motor occurs at the position where the permanent magnet passes through the air gap space corresponding to the slot between the two claw pole teeth, adding auxiliary slots appropriately to the claw pole teeth will increase the magnetic reluctance at the slot openings, preventing magnetic flux from entering the claw pole teeth from these openings. This is equivalent to increasing the number of claw pole slots in the torque motor, changing the pole-slot fit, and effectively improving the restoring torque. The purpose of adding auxiliary slots is essentially to reduce the harmonic order of the main restoring torque and increase its amplitude.

[0038] This invention improves the circumferential positive magnetic spring stiffness of the claw pole magnetic levitation torque motor by reasonably adding auxiliary slots.

[0039] The beneficial effects of the present invention are:

[0040] (1) The present invention provides a method for improving the stiffness of the circumferential positive magnetic spring of a torque motor. While ensuring the stiffness of the positive circumferential positive magnetic spring, an auxiliary groove is opened on the claw pole teeth to improve the stiffness of the circumferential positive magnetic spring and increase the accuracy of zero-point positioning.

[0041] (2) The present invention provides a claw pole magnetic levitation torque motor based on an auxiliary slot, which has high output torque and high positive circumferential positive magnetic spring stiffness, and can accurately perform zero-point positioning without the need for a mechanical spring. Attached Figure Description

[0042] Figure 1 This is an exploded view of the assembly of the present invention.

[0043] Figure 2 This is a diagram of the rotor assembly of the present invention.

[0044] Figure 3 This is a cross-sectional view of the stator assembly of the present invention.

[0045] Figure 4 This is a schematic diagram of the basic structure of the present invention.

[0046] Figure 5This is a schematic diagram showing the engagement of the claw teeth on the two claw poles.

[0047] Figure 6 This is a schematic diagram of the auxiliary tank parameters.

[0048] Explanation of reference numerals in the attached diagram: 100, claw pole; 100A, lower claw pole; 100B, upper claw pole; 110, auxiliary slot; 120, claw pole tooth; 120A, lower claw pole tooth; 120B, upper claw pole tooth; 200, permanent magnet; 200A, permanent magnet A; 200B, permanent magnet B; 300A, coil A; 300B, coil B; 400, outer casing; 410, threaded hole in the outer casing; 500, coil frame; 600, rotor core; 610, rotor connection port; Rr, outer diameter of the permanent magnet; Rs1, inner diameter of the claw pole tooth; Rs2, outer diameter of the claw pole tooth; Hp, height of the permanent magnet; Wp, width of the permanent magnet; Hc, height of the claw pole tooth; α, tilt angle of the claw pole tooth; t, distance between claw pole teeth; Wa, width of the auxiliary slot; Da, depth of the auxiliary slot. Detailed Implementation

[0049] The technical solution of the invention patent will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0050] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0052] Example 1

[0053] The following is for reference. Figures 1-3 The structure of a claw-pole magnetic levitation torque motor based on an auxiliary slot is described in a specific embodiment of the present invention.

[0054] This implementation example provides a structure for a claw-pole magnetic levitation torque motor based on an auxiliary slot, such as... Figure 1 As shown.

[0055] The torque motor consists of claw poles 100, permanent magnets 200, coils 300, housing 400, coil frame 500, and rotor core 600.

[0056] The rotor assembly consists of a rotor core 600 and a permanent magnet 200.

[0057] The rotor core 600 is fixed to external components through the rotor connection port 610, and outputs torque and angular displacement outward; the permanent magnets 200 are evenly distributed on the outer circular surface of the rotor core 600 in the circumferential direction; the magnetization direction of the permanent magnets 200 is radial magnetization, and the magnetization directions of adjacent permanent magnets 200A and permanent magnets 200B are opposite.

[0058] The stator assembly consists of claw pole 100, coil frame 500, coil 300, and housing 400; two sets of coils 300 are distributed on the coil frame, namely coil A 300A and coil B 300B; claw pole 100 and coil frame 500 are fixedly connected to housing 400, and housing 400 is fixedly connected to external components through threaded hole 410.

[0059] The claw pole 100 includes an upper claw pole 100B and a lower claw pole 100A arranged axially opposite each other. Each claw pole 100 has multiple claw pole teeth 120 on its opposite surface. The upper claw pole 100B and the lower claw pole 100A close together, and the claw pole teeth of one claw pole are inserted into the tooth grooves of the other claw pole, so that the upper claw pole teeth 120B and the lower claw pole teeth 120A surround the rotor assembly. The claw pole teeth 120 are evenly spaced circumferentially so that a tooth groove is formed between two adjacent claw pole teeth 120A and 120B. Each claw pole tooth 120 is provided with an auxiliary groove 110. The auxiliary groove 110 is located on the center line of the claw pole tooth 120, so that the claw pole tooth 120 is symmetrical about the auxiliary groove 110. The auxiliary groove 110 extends axially along the claw pole tooth 120 and thus penetrates the entire claw pole tooth 120.

[0060] The permanent magnet 200 can be rectangular or tile-shaped; in this embodiment, the tile shape is selected.

[0061] The pole arc coefficient of the rotor assembly is not fixed and can range from 0.8 to 1. In this implementation case, the pole arc coefficient selected is 0.9.

[0062] The number of claw pole teeth 120 can be arbitrary, as long as it is greater than 2. In this implementation case, the number of claw pole teeth is 18.

[0063] The claw tooth 120 can be trapezoidal or rectangular. In this embodiment, the claw tooth 120 is trapezoidal.

[0064] The number of permanent magnets 200 is equal to the number of claw pole teeth 120;

[0065] When the rotor assembly is in the zero position, each permanent magnet 200 is directly opposite to the two claw pole teeth 120, and the areas of the opposite sides are equal.

[0066] This torque motor utilizes the circumferential restoring torque between the stator and rotor assemblies for zero-point positioning, eliminating the need for mechanical springs.

[0067] Example 2

[0068] This implementation example provides a method for improving the circumferential stiffness of a claw-pole magnetic levitation torque motor based on an auxiliary slot. The method specifically includes the following steps:

[0069] S1. Determine the basic structural parameters of the torque motor.

[0070] Based on the design requirements, determine the following parameters for the claw-pole magnetic levitation torque motor based on the auxiliary slot: outer diameter Rr of the permanent magnet 200, inner diameter Rs1 and Rs2 of the claw-pole teeth 120, thickness Lp, height Hp, width Wp, number N of the permanent magnet 200 and claw-pole teeth 120, working air gap g between the permanent magnet 200 and claw-pole teeth 120, and maximum axial working stroke Y of the torque motor. Specifically, as follows: Figure 1 , Figure 4 As shown;

[0071] S2. Determine the initial dimensions of the claw pole teeth.

[0072] According to the formula Determine the height Hc of the claw pole teeth 120; determine the inclination angle α of the claw pole teeth 120 according to the suggested value range of 65°≤α≤85°; determine the spacing t of the claw pole teeth 120 according to the suggested value range of t>1mm. Specifically, as follows... Figure 5 As shown;

[0073] S3: Calculate the circumferential restoring torque and electromagnetic torque

[0074] A finite element simulation model was constructed to calculate the restoring torque at different angular displacements and the electromagnetic torque at zero position at different excitation currents, and the angular displacement-restoring torque curve was plotted. The gain of the angular displacement-restoring torque curve at each position is the circumferential positive magnetic spring stiffness at that position. If the zero-point gain is negative, it indicates that the torque motor has a positive circumferential positive magnetic spring stiffness.

[0075] S4: Optimize electromagnetic torque

[0076] Based on ensuring the torque motor has positive circumferential magnetic spring stiffness, the Taguchi method is adopted, with electromagnetic torque as the optimization objective. Within the suggested value range described in S2, the height Hc, tilt angle α, and spacing t of the claw pole teeth 120 are used as adjustable parameters, and an orthogonal array is constructed for experimental analysis. The optimal height Hc, tilt angle α, and spacing t of the claw pole teeth 120 are then selected using signal-to-noise ratio analysis.

[0077] S5: Open an auxiliary groove 110 on the center line of the claw tooth 120 and determine the initial size.

[0078] Based on the optimal design parameters selected from S4, a three-dimensional model of the torque motor was drawn, and an auxiliary groove 110 was created on the center line of the claw pole tooth 120. The recommended value range is g ≤ W. a ≤2t determines the width Wa of the auxiliary groove 110, and according to the suggested value range, it is D. a ≤g determines the depth Da of the auxiliary slot 110, specifically as follows: Figure 6 As shown;

[0079] S6: Calculate the circumferential restoring torque and electromagnetic torque, and optimize the circumferential restoring torque.

[0080] A finite element simulation model was constructed to calculate the restoring torque at different angular displacements and the electromagnetic torque at zero position under different excitation currents. Using the Taguchi method, with the positive circumferential magnetic spring stiffness at zero point as the optimization objective, and within the suggested value range described in S5, the width Wa and depth Da of the auxiliary groove 110 were used as adjustable parameters. An orthogonal array was constructed for experimental analysis. The optimal width Wa and depth Da of the auxiliary groove 110 were selected using signal-to-noise ratio analysis.

[0081] The embodiments described in this specification are merely examples of implementations of the inventive concept. The scope of protection of this invention should not be considered as limited to the specific forms stated in the embodiments. The scope of protection of this invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims

1. A claw-pole magnetic levitation torque motor based on an auxiliary slot, comprising a stator assembly and a rotor assembly, characterized in that: The rotor assembly consists of a rotor core and permanent magnets; The rotor core is fixed to external components through the rotor connection port, and outputs torque and angular displacement outward; permanent magnets are evenly distributed on the outer circumferential surface of the rotor core; the magnetization direction of the permanent magnets is radial, and the magnetization direction of adjacent permanent magnets is opposite. The stator assembly consists of two claw poles, a coil frame, coils, and a housing; Coils are distributed on the coil frame; the claw poles and coil frame are fixedly connected to the outer shell, and the outer shell is fixedly connected to external components through the outer shell threaded holes; the claw poles include upper claw poles and lower claw poles arranged opposite each other along the axial direction, each claw pole has multiple claw pole teeth on its opposite surface, the claw pole teeth are evenly spaced along the circumference, and a tooth groove is formed between two adjacent claw pole teeth; the upper claw poles and lower claw poles close up and down, the claw pole teeth of the claw poles are inserted into the tooth grooves of the other claw poles, and the upper claw pole teeth and lower claw pole teeth surround the rotor assembly; Each claw tooth is provided with an auxiliary groove; the auxiliary groove is located on the center line of the claw tooth, so that the claw tooth is symmetrical about the auxiliary groove; the auxiliary groove extends along the axial direction of the claw tooth and thus runs through the entire claw tooth; The design method of a claw-pole magnetic levitation torque motor includes the following steps: S1: Determine the basic structural parameters of the torque motor; According to the design requirements, determine the outer diameter Rr of the permanent magnet, the inner diameter Rs1 of the claw pole teeth, the outer diameter Rs2 of the claw pole teeth, the thickness Lp of the permanent magnet, the height Hp of the permanent magnet, the width Wp of the permanent magnet, the number N of the permanent magnet and claw pole teeth, the maximum single-sided axial working stroke Y of the torque motor, and the working air gap g of the torque motor. S2: Determine the initial dimensions of the claw pole teeth; The method for determining the initial dimensions of the claw pole teeth includes: the value range of the claw pole tooth height Hc is as follows: The range of the claw pole tooth inclination angle α is 65°≤α≤85°, and the range of the claw pole tooth spacing is t>1mm; S3: Calculate the circumferential restoring torque and electromagnetic torque; A finite element simulation model was constructed to calculate the restoring torque at different angular displacements and the electromagnetic torque at zero position at different excitation currents, and the angular displacement-restoring torque curve was plotted. The gain of the angular displacement-restoring torque curve at each position is the circumferential positive magnetic spring stiffness at that position. If the zero-point gain is negative, it indicates that the torque motor has circumferential positive magnetic spring stiffness. S4: Optimize electromagnetic torque; Based on ensuring that the torque motor has circumferential positive magnetic spring stiffness, an optimization design method is adopted, with electromagnetic torque as the optimization target. Within the suggested value range described in step S2, the claw pole tooth height Hc, claw pole tooth tilt angle α, and claw pole tooth spacing t are used as adjustable parameters for simulation analysis; the optimal claw pole tooth height Hc, claw pole tooth tilt angle α, and claw pole tooth spacing t are selected. S5: Open an auxiliary groove on the center line of the claw pole teeth and determine the initial size; Based on the optimal design parameters selected in step S4, a three-dimensional model of the torque motor is drawn, and an auxiliary groove is opened on the center line of the claw pole teeth. The method for determining the initial size of the auxiliary groove of the claw pole teeth includes: the value range of the auxiliary groove width Wa is g≤W a ≤2t, the range of values ​​for the auxiliary groove depth Da is D a ≤g; S6: Calculate the circumferential restoring torque and electromagnetic torque, and optimize the circumferential restoring torque; A finite element simulation model was constructed to calculate the restoring torque at different angular displacements and the electromagnetic torque at zero position at different excitation currents. An optimization design method was adopted, with the positive circumferential magnetic spring stiffness at zero point as the optimization target. Within the suggested value range described in step S5, the auxiliary slot width Wa and auxiliary slot depth Da were used as adjustable parameters for simulation analysis. The optimal auxiliary slot width Wa and auxiliary slot depth Da were selected.

2. The claw-pole magnetic levitation torque motor based on an auxiliary slot as described in claim 1, characterized in that, When the rotor assembly is in the zero position, each permanent magnet is directly opposite two claw pole teeth, and the areas of the opposite pole teeth are equal.

3. A claw-pole magnetic levitation torque motor based on an auxiliary slot as described in claim 1, characterized in that, Permanent magnets are rectangular or tile-shaped.

4. A claw-pole magnetic levitation torque motor based on an auxiliary slot as described in claim 1, characterized in that, The polar arc coefficient of the rotor assembly is 0.8-1.

5. A claw-pole magnetic levitation torque motor based on an auxiliary slot as described in claim 1, characterized in that, The claw teeth are trapezoidal or rectangular.

6. A claw-pole magnetic levitation torque motor based on an auxiliary slot as described in claim 1, characterized in that, The number of permanent magnets is equal to the number of claw pole teeth.

7. A claw-pole magnetic levitation torque motor based on an auxiliary slot as described in claim 1, characterized in that, Two sets of coils are used.

Images