A miniature motor

Abstract

This utility model relates to the field of motor technology, specifically to a micro motor, which includes a housing with an internal cavity; a stator fixed within the cavity of the housing; an outer rotor rotatably connected to the outer periphery of the stator; a magnetic ring constructed as a circular ring structure and fixed to the inner periphery of the outer rotor, with a gap between the inner periphery of the magnetic ring and the outer periphery of the stator; and a drive shaft coaxially fixedly connected to the outer rotor and rotatably connected to the housing. This application uses a circular magnetic ring instead of sheet-like silicon steel sheets. In the micro motor, the magnetic ring is directly fitted to the inner periphery of the outer rotor during installation, greatly reducing the installation accuracy requirements and operational difficulty in a limited space. This makes it easier to achieve precise positioning and fixation during installation, preventing the magnetic ring from falling off or shifting, thereby ensuring the uniformity of the rotor's magnetic field.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to a micro motor. Background Technology

[0002] In the field of motor technology, the rotor, as a key component for converting electrical energy into mechanical energy, directly affects the overall operation of the motor. Silicon steel sheets, as an important part of traditional rotors, can be installed and fixed in conventionally sized motors using certain processes to meet basic operational requirements. However, with the continuous miniaturization of motors, the dimensions of components within micromotors have significantly decreased, increasing the precision requirements and operational difficulty of silicon steel sheet installation. Traditional installation methods struggle to accurately position and fix silicon steel sheets within limited space. Furthermore, due to the higher operating speeds of micromotors and space constraints, the centrifugal forces and vibrations experienced by the silicon steel sheets are more pronounced, making them prone to detachment and displacement. This detachment and displacement directly disrupts the uniformity of the rotor's magnetic field, leading to increased torque fluctuations, operational instability, and reduced efficiency, severely restricting the performance and reliable operation of micromotors. Utility Model Content

[0003] The purpose of this invention is to provide a micro motor to solve the problem in the prior art that silicon steel sheets are difficult to assemble, which affects the uniformity of the rotor magnetic field.

[0004] The technical solution of this utility model is: a micro motor, comprising: The shell has an internal cavity; The stator is fixedly disposed within the receiving cavity of the housing; The outer rotor is rotatably connected to the outer periphery of the stator; A magnetic ring, constructed as a circular ring structure, is fixed to the inner peripheral wall of the outer rotor, and a gap is formed between the inner peripheral side of the magnetic ring and the outer peripheral side of the stator. A drive shaft is coaxially fixedly connected to the outer rotor, and the drive shaft is rotatably connected to the housing.

[0005] Preferably, the housing includes a top cover and a base, the top cover and the base are detachably connected and enclose a receiving cavity, the top cover has a first mounting hole communicating with the receiving cavity, the base has a second mounting hole coaxial with the first mounting hole, and the drive shaft is rotatably supported on the housing through the first mounting hole and the second mounting hole respectively.

[0006] Preferably, the upper cover extends into the receiving cavity with a support cylinder, and the stator is fixed to the outer periphery of the support cylinder.

[0007] Preferably, the drive shaft includes a first shaft segment, a second shaft segment, a third shaft segment, and a fourth shaft segment along its axis, with the diameters of the second shaft segment, the third shaft segment, and the fourth shaft segment decreasing progressively to form a stepped shaft structure.

[0008] Preferably, the outer rotor includes a rotor flange and a rotor yoke. The rotor yoke is constructed as a ring structure. The rotor yoke is fixed to the edge of the end face of the rotor flange. The magnetic ring is fixed to the inner sidewall of the rotor yoke. The rotor flange is interference-fitted with the third shaft segment.

[0009] Preferably, the rotor flange is provided with a hollow reinforcing cylinder, the outer contour of which is inclined and tapered, and the inner wall of which is interference-fitted with the third shaft segment.

[0010] Preferably, the diameter of the first shaft segment is smaller than the diameter of the second shaft segment, the first shaft segment is rotatably connected to the first mounting hole, and the fourth shaft segment is rotatably connected to the second mounting hole.

[0011] Compared with the prior art, the advantages of this utility model are: By replacing the sheet-like silicon steel sheets with a circular magnetic ring, the magnetic ring can be directly fitted to the inner circumferential wall of the outer rotor during installation in the micro motor. This greatly reduces the installation accuracy requirements and operational difficulties in a limited space, making it easier to achieve precise positioning and fixation during installation. Compared with silicon steel sheets, the magnetic ring has higher overall structural strength and stability. When the micro motor is running at high speed and is significantly affected by centrifugal force and vibration due to space constraints, the micro motor can effectively resist centrifugal force and vibration generated during operation, preventing the magnetic ring from falling off or shifting, thereby ensuring the uniformity of the rotor magnetic field. Attached Figure Description

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the structure of a micro motor according to the present invention; Figure 2 This is a cross-sectional view of a micro motor according to the present invention. Figure 3 This is a schematic diagram of the structure of the external rotor described in this utility model; Figure 4 This is a schematic diagram of the structure of the transmission shaft described in this utility model.

[0013] Explanation of reference numerals in the attached figures: 1. Housing; 11. Receiving cavity; 12. Top cover; 121. First mounting hole; 13. Base; 131. Second mounting hole; 14. Support cylinder; 2. Stator; 3. Outer rotor; 31. Rotor flange; 32. Rotor yoke; 33. Reinforcing cylinder; 4. Magnetic ring; 5. Drive shaft; 51. First shaft section; 52. Second shaft section; 53. Third shaft section; 54. Fourth shaft section; 6. First bearing; 7. Second bearing. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0015] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0016] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", 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.

[0017] like Figure 1 and Figure 2As shown, a micro motor includes a housing 1, a stator 2, and an outer rotor 3. The housing 1 has an internal cavity 11 to accommodate the stator 2 and the outer rotor 3. The stator 2 is fixed within the cavity 11 of the housing 1. The outer rotor 3 is rotatably connected to the outer periphery of the stator 2. A magnetic ring 4 is fixedly mounted on the outer rotor 3. The magnetic ring 4 is constructed as a circular ring, with a gap between its inner periphery and the outer periphery of the stator 2. The integral structure provided by the magnetic ring 4 provides a continuous and uniform circumferential magnetic field, effectively eliminating the problem of magnetic field inhomogeneity caused by splicing multiple silicon steel sheets, thereby significantly reducing motor torque fluctuations and making the motor run more smoothly. The magnetic ring 4, as a complete rigid body, is fixed to the inner periphery of the outer rotor 3, and its integrity and concentricity are far superior to those of individually glued silicon steel sheet assemblies. This not only avoids the problem of small silicon steel sheets falling off or shifting due to centrifugal force or vibration under high-speed rotation, but also significantly reduces the risk of uneven air gap, performance degradation, or even rotor rubbing caused by magnetic pole misalignment, improving the reliability and lifespan of the micro motor under long-term high-speed operation.

[0018] The housing 1 is rotatably connected to a drive shaft 5, which is coaxially fixed to the outer rotor 3. The outer rotor 3 and the stator 2 interact electromagnetically, thereby driving the drive shaft 5 to rotate.

[0019] The housing 1 includes a top cover 12 and a base 13. The top cover 12 is constructed as a flat plate structure, and the base 13 is recessed to form an accommodating space. The top cover 12 and the base 13 are detachably connected by bolts and enclose each other to form an accommodating cavity 11. Preferably, the outer surface of the housing 1 has a cubic contour structure, which greatly improves the engineering practicality and integrability of the micro motor.

[0020] The top cover 12 has a first mounting hole 121 that communicates with the receiving cavity 11. The bottom of the housing 1 has a second mounting hole 131 that communicates with the receiving cavity 11. The first mounting hole 121 and the second mounting hole 131 are coaxially arranged. The drive shaft 5 is rotatably connected to the first mounting hole 121 and the second mounting hole 131. One end of the drive shaft 5 is rotatably connected to the first mounting hole 121 through a bearing, and the other end of the drive shaft 5 extends out of the base 13 for driving external components.

[0021] A support cylinder 14 extends from the upper cover 12 toward the receiving cavity 11. The support cylinder 14 is coaxially connected with the first mounting hole 121, and the stator 2 is fixed to the outer periphery of the support cylinder 14. Preferably, the support cylinder 14 and the upper cover 12 are integrally formed to ensure that the central axis of the stator 2 is coaxial with the rotational central axis of the drive shaft 5.

[0022] like Figure 2 and Figure 3As shown, the drive shaft 5 includes a first shaft segment 51, a second shaft segment 52, a third shaft segment 53, and a fourth shaft segment 54 along its axis. The diameter of the first shaft segment 51 is smaller than that of the second shaft segment 52, and the diameters of the second shaft segment 52, the third shaft segment 53, and the fourth shaft segment 54 decrease progressively, forming a stepped shaft structure. Shaft segments of different diameters are matched with parts of different sizes to achieve precise axial positioning and reliable radial support, simplifying the assembly process. Specifically, the first shaft segment 51 is rotatably connected to the first mounting hole 121 via the first bearing 6. Preferably, the end of the first shaft segment 51 is located inside the first mounting hole 121, so that the output end of the drive shaft 5 on the base 13 side of the micro motor is a single-end output, while the top cover 12 side forms a complete and flat closed surface. This greatly reduces the axial size of the micro motor, making the structure more compact and facilitating installation and integration in space-constrained applications. At the same time, it effectively prevents external dust, impurities, liquids, etc., from entering the first bearing 6 and the electromagnetic air gap area inside the motor, extending the motor's lifespan.

[0023] The second shaft segment 52 is rotatably connected to the support cylinder 14. Optionally, a gap is formed between the second shaft segment 52 and the support cylinder 14. Optionally, the third shaft segment 53 is partially built into the support cylinder 14, and a portion of the outer rotor 3 is fixedly connected to the third shaft segment 53 in the support cylinder 14. The fourth shaft segment 54 is rotatably connected to the base 13 via the second bearing 7. The end face of the third shaft segment 53 is axially positioned by the second bearing 7. Preferably, the end face of the third shaft segment 53 is flush with the end face inside the base 13. The end face of the second shaft segment 52 is axially positioned by the first bearing 6. That is, the second shaft segment 52 and the third shaft segment 53 are confined within the receiving cavity 11 along their axes. The radial runout of the drive shaft 5 is controlled within a controllable range, ensuring that the air gap between the outer rotor fixed thereon and the stator 2 fixed to the housing 1 remains uniform and effectively resisting the radial force from the fourth shaft segment 54, which is the output end, preventing the shaft from bending and deforming.

[0024] The outer rotor 3 includes a rotor flange 31 and a rotor yoke 32. The rotor flange 31 is constructed in a disc shape and is coaxially fixed to the third shaft section 53. Preferably, the rotor flange 31 and the third shaft section 53 are interference-fitted. The rotor yoke 32 is constructed in a ring structure and is fixed to the edge of the end face of the rotor flange 31, thus surrounding the outer periphery of the stator 2. Preferably, the inner sidewall of the rotor yoke 32 has an inwardly recessed annular groove, and the magnetic ring 4 is fixed in the groove. The constraint effect of the rotor yoke 32 resists the centrifugal force on the magnetic ring 4. The uniform magnetic field generated by the magnetic ring 4 makes the output of the micro motor smooth during rotation, thereby avoiding torque fluctuations caused by assembly gaps and magnetic flux errors between multiple silicon steel sheets.

[0025] like Figure 4As shown, the rotor flange 31 is provided with a hollow reinforcing cylinder 33. The outer contour of the reinforcing cylinder 33 is inclined and tapered. The inner wall of the reinforcing cylinder 33 is interference-fitted with the third shaft section 53. Part of the reinforcing cylinder 33 is located inside the support cylinder 14, which improves the compactness of the overall structure. At the same time, it can reduce the mass of the rotor flange 31, strengthen the connection structure in the critical connection parts, reduce the rotational inertia of the rotor flange 31, improve the acceleration and deceleration response speed of the micro motor, and improve the initial dynamic balance performance of the rotor.

[0026] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. It is obvious to those skilled in the art that this utility model is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and therefore, all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within this utility model.

Claims

1. A micromotor, characterized by comprising: include: The shell (1) has an internal cavity (11). The stator (2) is fixedly disposed in the receiving cavity (11) of the housing (1); The outer rotor (3) is rotatably connected to the outer periphery of the stator (2); The magnetic ring (4) is constructed as a circular ring structure and is fixed to the inner peripheral wall of the outer rotor (3). The inner peripheral side of the magnetic ring (4) forms a gap with the outer peripheral side of the stator (2). The drive shaft (5) is coaxially fixedly connected to the outer rotor (3), and the drive shaft (5) is rotatably connected to the housing (1).

2. The micromotor according to claim 1, wherein: The housing (1) includes a top cover (12) and a base (13). The top cover (12) and the base (13) are detachably connected and enclose a cavity (11). The top cover (12) has a first mounting hole (121) communicating with the cavity (11). The base (13) has a second mounting hole (131) coaxial with the first mounting hole (121). The drive shaft (5) is rotatably supported on the housing (1) through the first mounting hole (121) and the second mounting hole (131) respectively.

3. A micromotor according to claim 2, wherein: The upper cover (12) extends into the cavity (11) with a support cylinder (14), and the stator (2) is fixed to the outer periphery of the support cylinder (14).

4. The micromotor of claim 2, wherein: The drive shaft (5) includes a first shaft segment (51), a second shaft segment (52), a third shaft segment (53) and a fourth shaft segment (54) along its axis. The diameters of the second shaft segment (52), the third shaft segment (53) and the fourth shaft segment (54) decrease step by step to form a stepped shaft structure.

5. A micromotor according to claim 4, wherein: The outer rotor (3) includes a rotor flange (31) and a rotor yoke (32). The rotor yoke (32) is constructed as a ring structure. The rotor yoke (32) is fixed to the edge of the end face of the rotor flange (31). The magnetic ring (4) is fixed to the inner side wall of the rotor yoke (32). The rotor flange (31) is interference-fitted with the third shaft segment (53).

6. A micromotor according to claim 5, wherein: The rotor flange (31) is provided with a hollow reinforcing cylinder (33), the outer contour of which is inclined and tapered, and the inner wall of which is interference-fitted with the third shaft section (53).

7. A micromotor according to claim 4, wherein: The diameter of the first shaft segment (51) is smaller than the diameter of the second shaft segment (52). The first shaft segment (51) is rotatably connected to the first mounting hole (121), and the fourth shaft segment (54) is rotatably connected to the second mounting hole (131).

Images