Miniature mute stepping motor

Abstract

The utility model discloses a miniature mute stepping motor, comprising a stator assembly and a rotor assembly, the stator assembly comprises a casing, a coil holder and a pole plate, the rotor assembly comprises a central shaft and a magnetic ring structure fixed on the central shaft, the magnetic ring structure comprises a magnetic ring rack fixed on the central shaft, and the magnetic ring rack is fixed on the central shaft. And the magnetic rings are respectively fixed at two ends of the magnetic ring frame. Through the innovative double-end magnetic ring structure, the design of the integrated pole plate wire frame, the innovative design of the tooth shape and the application of high-performance materials, the problems that a traditional stepping motor is large in noise and unstable in low speed are solved, and the motor has the advantages of being mute, efficient and compact and is suitable for high-precision automatic equipment.

Description

Technical Field

[0001] This utility model relates to a miniature silent stepper motor. Background Technology

[0002] Stepper motors are widely used in various automated control systems. A traditional stepper motor typically consists of a motor coil, motor housing, pole plates, and a circular multi-pole magnetic ring. When the motor coil is energized, it generates a magnetic field, creating different magnetic poles between the housing and pole plates that interact with the circular multi-pole magnetic ring to transmit power. The magnetic ring in a traditional stepper motor is usually a monolithic structure with a uniform magnetic field distribution. This leads to abrupt changes in magnetic resistance when the stator and rotor teeth are aligned, resulting in significant cogging torque, affecting low-speed stability, and often causing substantial vibration and high noise under the same electromagnetic torque, thus impacting the user experience. Utility Model Content

[0003] To address the aforementioned problems, this utility model provides a miniature silent stepper motor. Through the double-headed magnetic ring and a special housing plate tooth profile design, the stator and rotor magnetic fields are smoothly cut, significantly reducing the cogging torque and effectively solving the problems pointed out in the background art.

[0004] The technical solution adopted in this utility model is:

[0005] A miniature silent stepper motor includes a stator assembly and a rotor assembly. The stator assembly includes a housing, a wire frame, and pole plates. The rotor assembly includes a central shaft and a magnetic ring structure fixed on the central shaft. The magnetic ring structure includes a magnetic ring frame fixed on the central shaft and magnetic rings respectively fixed at both ends of the magnetic ring frame.

[0006] Preferably, there are two electrode plates, located on the outer sides of the two magnetic rings respectively, and the bases of the two electrode plates are overlapped and fixed together. The electrode plate teeth face the outer ends of the corresponding magnetic rings respectively. The wire frame includes two wire frame units respectively disposed on the outer sides of the electrode plate teeth. The two wire frame units are fixedly connected together. The bases of the two electrode plates are located between the two wire frame units. The wire frame unit is provided with a coil winding area, and a coil is wound in the coil winding area. There are two housings, located on the outer sides of the two electrode plates respectively, and the interior of both housings is provided with housing teeth that match the inner electrode plate teeth.

[0007] Preferably, the wire frame is made of plastic, the electrode plate is made of metal, and the wire frame and the electrode plate are integrally formed.

[0008] Preferably, the magnetic ring is made of high-performance neodymium iron boron permanent magnet material.

[0009] Preferably, the high-performance neodymium iron boron permanent magnet material has a remanence of 0.6~0.8T, a coercivity of 300~500kA / m, and a maximum energy product of 60~90kJ / m³.

[0010] Preferably, the magnetic ring has 5 to 7 pole pairs, an outer diameter of 5.5 to 7.5 mm, and a thickness of 0.8 to 1.8 mm.

[0011] Preferably, the tooth profiles of the electrode plate teeth and the housing teeth are both multi-segment tooth profiles. The multi-segment tooth profile includes a tooth root, a tooth surface, and a tooth tip. The shape of the tooth surface consists of an arc that bulges outward from the center and straight line segments connecting the two ends of the arc. The arc is tangent to the straight line. The top of the tooth surface is connected to the tooth tip through a tooth surface rounded corner, and the bottom is connected to the tooth root through a tooth surface draft angle.

[0012] The innovative points of this utility model are as follows:

[0013] 1. Double-headed magnetic ring design:

[0014] Traditional stepper motors use an integral magnetic ring, which results in a uniform magnetic field distribution and causes sudden changes in cogging torque, affecting low-speed stability. This invention uses a double-headed magnetic ring structure fixed at both ends of the magnetic ring frame, which makes the magnetic field distribution change in a stepped manner, significantly reducing cogging torque and improving running stability. The layout of the double magnetic rings optimizes the interaction of magnetic fields and reduces sudden changes in magnetic resistance, thereby reducing vibration and noise.

[0015] 2. Integrated design of electrode plate and wire frame:

[0016] The electrode bases are stacked and fixed, and the electrode teeth face the outer end of the corresponding magnetic ring. The wire frame units are set on the outside of the electrode teeth and fixedly connected to form a compact structure. The wire frame and electrode plates are made of plastic and metal in one piece, which simplifies the assembly process, enhances the structural stability, and reduces the additional noise caused by loose parts.

[0017] 3. High-performance neodymium iron boron magnetic ring material:

[0018] The magnetic ring uses neodymium iron boron material with optimized remanence (0.6~0.8T), coercivity (300~500kA / m) and maximum energy product (60~90kJ / m³) to improve magnetic field strength and efficiency. The refined design of the number of pole pairs (5~7 pairs) and outer diameter (5.5~7.5mm) of the magnetic ring further balances torque output and noise control.

[0019] 4. Tooth profile design of electrode plate teeth and housing teeth:

[0020] Traditional stepper motors often have triangular or trapezoidal tooth profiles, resulting in uneven magnetic field distribution, which can easily lead to cogging torque and vibration noise. This technical solution adopts a multi-segment tooth profile, which connects the tooth root, tooth surface and tooth tip with a smooth transition curve to optimize the magnetic field distribution.

[0021] The tooth surface bulges outward in the middle, and the tooth tip is tangentially connected to the tooth surface through the rounded corners of the tooth surface, ensuring a natural transition of the magnetic field and reducing local magnetic field concentration;

[0022] The tooth height is designed to be 0.4 to 0.42 times the air gap diameter, and the tooth width is 1.12 to 1.18 times the width of a single-stage air gap magnetic field. The magnetic field uniformity is further improved through the optimization of geometric parameters.

[0023] The beneficial effects of this utility model are as follows:

[0024] 1. Significantly improved noise reduction performance:

[0025] The stepped magnetic field distribution and double magnetic ring design effectively suppress sudden changes in cogging torque and reduce vibration and noise during operation, making it especially suitable for scenarios with high requirements for quiet operation.

[0026] 2. Smoother operation at low speeds:

[0027] The optimized magnetic field distribution reduces magnetic resistance fluctuations, making the motor's torque output more uniform at low speeds and avoiding the "jerkiness" common in traditional motors.

[0028] 3. Compact and reliable structure:

[0029] The integrated design of the electrode plate and the wire frame reduces the number of parts, lowers the risk of assembly errors, and enhances the overall mechanical strength and extends the service life.

[0030] 4. High-efficiency output:

[0031] High-performance neodymium iron boron materials combined with precise magnetic ring parameters ensure that the motor can still provide high energy density and stable electromagnetic torque under the premise of miniaturization;

[0032] 5. Significantly reduces static cogging torque:

[0033] Multi-segment tooth profile makes the magnetic field distribution more uniform, reduces static cogging torque by more than 40%, and improves the positioning accuracy and stability of the motor.

[0034] Simulation data shows that torque ripple is reduced by 15% to 42% compared to traditional triangular or trapezoidal tooth profiles;

[0035] 6. Reduce operating vibration and noise:

[0036] The smooth tooth design and synchronous rotation mechanism effectively suppress periodic vibrations, reducing the vibration amplitude by 30% to 50%.

[0037] The measured noise reduction is 10dB(A), making it especially suitable for quiet environments such as medical equipment and precision instruments.

[0038] This invention solves the problems of high noise and unstable low speed of traditional stepper motors through innovative double-headed magnetic ring structure, integrated pole plate wire frame design, innovative tooth design, and application of high-performance materials. It is characterized by quietness, high efficiency and compactness, and is suitable for high-precision automated equipment. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of this utility model;

[0040] Figure 2 This is a cross-sectional structural diagram of the present invention;

[0041] Figure 3 This is a schematic diagram of the internal structure of the present invention;

[0042] Figure 4 This is a schematic diagram of the wire frame structure;

[0043] Figure 5 This is a schematic diagram of the pole plate and rotor assembly.

[0044] Figure 6 This is a schematic diagram of the magnetic ring structure;

[0045] Figure 7 This is a schematic diagram of the casing structure;

[0046] Figure 8 The simulated dynamic tooth cogging torque diagram for the triangular tooth profile;

[0047] Figure 9 The simulated dynamic tooth cogging torque diagram for the trapezoidal tooth profile;

[0048] Figure 10 This is a simulated dynamic tooth cogging torque diagram of the multi-segment tooth profile of this utility model. Detailed Implementation

[0049] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0050] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0051] Furthermore, in the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and 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. Therefore, they should not be construed as limitations on this utility model.

[0052] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more, unless otherwise expressly defined.

[0053] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., 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 utility model according to the specific circumstances.

[0054] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0055] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0056] like Figure 1-7 As shown, a miniature silent stepper motor includes a stator assembly and a rotor assembly. The stator assembly includes a housing 1, a wire frame 2, and a pole plate 3. The rotor assembly includes a central shaft 4 and a magnetic ring structure 5 fixed on the central shaft 4. The magnetic ring structure 5 includes a magnetic ring frame 51 fixed on the central shaft 4 and magnetic rings 52 respectively fixed at both ends of the magnetic ring frame 51.

[0057] There are two pole plates 3, which are located on the outside of the two magnetic rings 52 respectively, and the bases of the two pole plates 3 are overlapped and fixed together. The pole plate teeth 31 are respectively facing the outer end of the corresponding magnetic ring 52. The wire frame 2 includes two wire frame units 21 respectively arranged on the outside of the pole plate teeth 31. The two wire frame units 21 are fixedly connected together. The bases of the two pole plates 3 are located between the two wire frame units 21. The wire frame unit 21 is provided with a coil winding area 22, and a coil 23 is wound in the coil winding area 22.

[0058] The wire frame 2 is made of plastic, and the electrode plate 3 is made of metal. The wire frame 2 and the electrode plate 3 are integrally formed.

[0059] The magnetic ring 52 is made of high-performance neodymium iron boron permanent magnet material.

[0060] The high-performance neodymium iron boron permanent magnet material has a remanence of 0.6~0.8T, a coercivity of 300~500kA / m, and a maximum energy product of 60~90kJ / m³.

[0061] The magnetic ring 52 has 5 to 7 pole pairs, an outer diameter of 5.5 to 7.5 mm, and a thickness of 0.8 to 1.8 mm.

[0062] Both the electrode plate tooth 31 and the housing tooth 11 have multi-segment tooth profiles. The multi-segment tooth profile includes a tooth root a, a tooth surface b, and a tooth tip c. The shape of the tooth surface b consists of an arc that bulges outward from the middle and straight line segments connecting the two ends of the arc. The arc is tangent to the straight line. The top of the tooth surface b is connected to the tooth tip c through a tooth surface rounded corner, and the bottom is connected to the tooth root a through a tooth surface draft angle.

[0063] Furthermore, the electrode teeth 31 on the two electrode plates 3 are asymmetrically designed, and the housing teeth 11 on the two housings 1 are asymmetrically designed. The specific design scheme is as follows: the electrode teeth 31 are pre-rotated relative to the housing teeth 11 by a step angle, such as 12.85°, so that the stator and rotor teeth always maintain a smooth magnetic circuit during the movement; after rotation, the gap distribution between the electrode teeth 31 and the housing teeth 11 is more uniform, avoiding sudden changes in local magnetic resistance, thereby suppressing torque fluctuations.

[0064] The tooth root width of the multi-segment linear tooth profile is 1.12 to 1.18 times the width of the single-stage air gap magnetic field.

[0065] The angle of the tooth surface draft angle is: .

[0066] The tooth height of the multi-segment tooth profile is 0.4 to 0.42 times the air gap diameter.

[0067] The arc of the tooth surface b is the maximum outer diameter arc that is tangent to the straight segment of the tooth surface b and connects to the tooth tip c.

[0068] The top of the multi-segment tooth profile is tangent to the tooth surface b with a minimum manufacturable radius.

[0069] The working principle of this utility model:

[0070] 1. Optimization of magnetic field distribution in the double-headed magnetic ring design:

[0071] Traditional problem: The uniform magnetic field distribution of the integral magnetic ring in traditional stepper motors causes a sudden change in magnetic resistance and cogging torque when the stator and rotor teeth are aligned, resulting in vibration and noise, especially causing unstable operation at low speeds.

[0072] Solution:

[0073] It adopts a double-headed magnetic ring structure, fixing two independent magnetic rings at both ends of the magnetic ring frame, replacing the traditional integral magnetic ring.

[0074] The magnetic field distribution of the double magnetic ring varies in a stepped manner rather than a uniform distribution. This design makes the change in magnetic resistance more gradual and significantly reduces the abrupt change in cogging torque.

[0075] Effect:

[0076] Reduce magnetic drag fluctuations, decrease the "jerkiness" during low-speed operation, optimize magnetic field interaction, reduce vibration and noise, and improve quietness performance.

[0077] 2. Integrated design of electrode plate and wire frame:

[0078] Structural design:

[0079] The bases of the two plates are overlapped and fixed, with the plate teeth facing the outer ends of the corresponding magnetic rings, forming a symmetrical layout;

[0080] The wire frame is divided into two units, located on the outside of the electrode teeth, and is connected by a fixed connection to form a compact whole. The electrode base is embedded between the two wire frame units.

[0081] The wire frame and electrode plates are manufactured using a one-piece molding process combining plastic and metal.

[0082] Functional advantages:

[0083] Simplified assembly: Reduces the number of parts and assembly steps, and reduces additional noise caused by loosening;

[0084] Enhanced stability: The integrated design improves mechanical strength and prevents component displacement or vibration during operation;

[0085] Compactness: Suitable for miniaturized applications, such as precision equipment.

[0086] 3. Material and parameter optimization of high-performance NdFeB magnetic rings:

[0087] Material properties:

[0088] The magnetic ring uses neodymium iron boron permanent magnet material, and its specific parameters are as follows:

[0089] Remanence: 0.6~0.8T;

[0090] Coercivity 300~500kA / m;

[0091] Maximum energy product: 60~90 kJ / m³;

[0092] These parameters ensure high magnetic field strength and resistance to demagnetization.

[0093] Geometric design:

[0094] Number of pole pairs: 5~7 pairs, to balance torque output and speed requirements;

[0095] With an outer diameter of 5.5~7.5mm and a thickness of 0.8~1.8mm, the refined design is adapted to miniaturization requirements.

[0096] Effect:

[0097] Improve energy conversion efficiency to achieve high torque output in a small volume;

[0098] The material's high coercivity reduces magnetic field attenuation and extends its service life.

[0099] 4. Overall Operation Process:

[0100] Power-on phase:

[0101] An electric current passes through a coil on a wire frame, generating an alternating magnetic field;

[0102] Magnetic field interaction:

[0103] The magnetic field of the coil interacts with the stepped magnetic field of the double-headed magnetic ring, driving the rotor to rotate;

[0104] Because the magnetic field distribution is gentle and the magnetic resistance changes evenly, the sudden torque changes of traditional motors are avoided.

[0105] Power transmission:

[0106] The rotor outputs a smooth torque through the central shaft, and the integrated structure of the pole plates and the wire frame ensures that the power transmission is smooth and secure.

[0107] Optimization for quiet operation and low speed:

[0108] The dual magnetic ring design suppresses vibration, and the efficient magnetic field of neodymium iron boron material further reduces energy loss and noise.

[0109] Tooth profile comparison experiment:

[0110] Figure 8 Simulate dynamic cogging torque for triangular tooth profile;

[0111] Figure 9 Simulate dynamic cogging torque for trapezoidal tooth profile;

[0112] Figure 10 This utility model provides a simulation of dynamic tooth cogging torque using a multi-segment tooth profile.

[0113] according to Figure 8-10 As can be seen, Ansys Maxwell simulations show that torque ripple is reduced by 15-42%.

[0114] Meanwhile, the measured data shows that, under 12V / 120mA drive, compared with triangular tooth profile and trapezoidal tooth profile, the effective value of vibration velocity of multi-segment tooth profile decreased from 1.2mm / s to 0.7mm / s.

[0115] The core of the tooth profile design lies in optimizing the magnetic field distribution and mechanical structure through multi-segment tooth profile design and synchronous rotation mechanism of pole plate teeth and housing teeth, thereby significantly reducing static cogging torque and operating vibration noise. Its working principle can be divided into the following parts:

[0116] 1. Magnetic field optimization for multi-segment tooth profiles:

[0117] Problems with traditional tooth profiles: Traditional stepper motors use triangular or trapezoidal tooth profiles with sharp or symmetrical tooth surfaces, which leads to uneven distribution of the magnetic field at the tooth tip and root, resulting in localized magnetic flux density concentration. This unevenness generates a large static cogging torque and causes periodic vibration and noise during operation.

[0118] Solution for multi-segment tooth profiles:

[0119] Smoothly transitioning magnetic field distribution: Multi-segment tooth profile passes through a tooth surface that convexes outward from the center (see...) Figure 1-2 The tooth surface 32) achieves a smooth transition of the magnetic field. The tooth surface uses multi-segment lines to connect the tooth root and tooth tip, avoiding the sharp turns of the traditional tooth shape and making the magnetic field lines more evenly distributed.

[0120] Tooth surface rounding optimization: The tooth tip is tangentially connected to the tooth surface through the tooth surface rounding. This design ensures a natural transition of the magnetic field at the tooth tip and reduces abrupt changes in magnetic flux.

[0121] Geometric parameter matching: the tooth height is 0.4 to 0.42 times the air gap diameter; the tooth width is 1.12 to 1.18 times the width of a single-stage air gap magnetic field (single-stage width = tooth root circumference / number of magnetic poles), to ensure magnetic field coverage between adjacent teeth and reduce magnetic leakage;

[0122] Simulation verification: Magnetic field simulation using Ansys Maxwell ( Figure 3-5 As can be seen, the torque fluctuation of the multi-segment tooth profile is reduced by 15% to 42% compared with the traditional tooth profile, and the static tooth cogging torque is reduced by more than 40%.

[0123] 2. Synchronous design of electrode plate teeth and housing teeth:

[0124] The gap distribution between the electrode plate teeth and the housing teeth is more uniform, avoiding sudden changes in local magnetic reluctance and thus suppressing torque fluctuations;

[0125] Dynamic performance improvement: Actual test data shows that the synchronous design reduces the effective value of vibration velocity from 1.2 mm / s to 0.7 mm / s and the noise is reduced by 10 dB(A) (e.g., from 50 dB to 40 dB).

[0126] Finally, it should be noted that the above examples are merely specific embodiments of this utility model. Obviously, this utility model is not limited to the above embodiments and can have many variations. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of this utility model should be considered within the protection scope of this utility model.

Claims

1. A miniature silent stepper motor, characterized in that, The stator assembly includes a stator assembly and a rotor assembly. The stator assembly includes a housing (1), a wire frame (2), and a pole plate (3). The rotor assembly includes a central shaft (4) and a magnetic ring structure (5) fixed on the central shaft (4). The magnetic ring structure (5) includes a magnetic ring frame (51) fixed on the central shaft (4) and magnetic rings (52) fixed at both ends of the magnetic ring frame (51).

2. A miniature silent stepper motor according to claim 1, characterized in that, There are two pole plates (3), located on the outside of the two magnetic rings (52), and the bases of the two pole plates (3) are overlapped and fixed together. The pole plate teeth (31) face the outer end of the corresponding magnetic ring (52). The wire frame (2) includes two wire frame units (21) respectively set on the outside of the pole plate teeth (31). The two wire frame units (21) are fixedly connected together. The bases of the two pole plates (3) are located between the two wire frame units (21). The wire frame unit (21) is provided with a coil winding area (22). A coil (23) is wound in the coil winding area (22). There are two housings (1), located on the outside of the two pole plates (3), and the inside of the two housings (1) is provided with housing teeth (11) that match the inner pole plate teeth (31).

3. A miniature silent stepper motor according to claim 2, characterized in that, The wire frame (2) is made of plastic, and the electrode plate (3) is made of metal. The wire frame (2) and the electrode plate (3) are integrally formed.

4. A miniature silent stepper motor according to claim 3, characterized in that, The magnetic ring (52) is made of high-performance neodymium iron boron permanent magnet material.

5. A miniature silent stepper motor according to claim 4, characterized in that, The high-performance neodymium iron boron permanent magnet material has a remanence of 0.6~0.8T, a coercivity of 300~500kA / m, and a maximum energy product of 60~90kJ / m³.

6. A miniature silent stepper motor according to claim 5, characterized in that, The magnetic ring (52) has 5 to 7 pole pairs, an outer diameter of 5.5 to 7.5 mm, and a thickness of 0.8 to 1.8 mm.

7. A miniature silent stepper motor according to claim 2, characterized in that, The tooth profiles of the electrode plate tooth (31) and the housing tooth (11) are both multi-segment tooth profiles. The multi-segment tooth profile includes a tooth root (a), a tooth surface (b), and a tooth tip (c). The shape of the tooth surface (b) consists of an arc line that bulges outward from the middle and a straight line segment connecting the two ends of the arc line. The arc line is tangent to the straight line. The top of the tooth surface (b) is connected to the tooth tip (c) through a tooth surface rounded corner, and the bottom is connected to the tooth root (a) through a tooth surface draft angle.

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