Coreless Motor

Abstract

The present invention discloses a coreless cup motor, which comprises a rotor assembly and a stator assembly, wherein the rotor assembly comprises a coil and a motor shaft, and the stator assembly comprises a magnetic steel assembly, wherein the magnetic steel assembly is sleeved on the motor shaft, the motor shaft passes through the coil, and the motor shaft can drive the coil to rotate relative to the magnetic steel assembly with the central axis of the motor shaft as the rotation axis, the polarity of the magnetic steel assembly is arranged according to a Halbach array combination, and the magnetic force lines at both ends of the magnetic steel assembly along the central axis of the motor shaft constrain the magnetic force lines of the magnetic steel assembly in the middle of the central axis of the motor shaft within the effective area cut by the magnetic force lines of the coil; the present invention can effectively improve the performance of the coreless cup motor without increasing the weight of the magnetic steel and the outer diameter of the motor, so as to meet the high-performance manufacturing requirements of the micro motor.

Description

Technical Field

[0001] The invention relates to the technical field of motor manufacturing, and in particular to a coreless cup motor. Background Art

[0002] In the existing hollow cup motor structure, the magnetization method of the magnetic steel is unidirectional magnetization, the direction of its magnetic pole is very single, and the strength of its magnetic field along the axial direction is uniformly distributed. However, the coil itself has magnetic lines of force cutting effective areas and invalid areas. Since the strength of the magnetic field strength of the magnetic steel along the axial direction is uniformly distributed, a considerable part of the magnetic lines of force of the magnetic steel acts on the invalid area, resulting in an excess magnetic field. The excess magnetic field cannot improve the efficiency of the motor, and the part of the magnetic steel that produces invalid magnetic lines of force undoubtedly increases the overall weight of the motor, which seriously restricts the lightweight of the hollow cup motor. And when it is necessary to increase the speed of the motor, it is necessary to increase the volume of the magnetic steel, which will not only increase the overall volume of the hollow cup motor, but also further increase the useless magnetic lines of force of the magnetic steel, and also increase the weight of the magnetic steel, which is easy to cause the instability of the hollow cup motor structure. Summary of the invention

[0003] The purpose of the present invention is to provide a hollow cup motor, which can effectively improve the performance of the hollow cup motor without increasing the weight of the magnetic steel and the outer diameter of the motor, so as to meet the high-performance manufacturing requirements of the micro motor.

[0004] In order to achieve the above purpose, the present invention discloses a hollow cup motor, which includes a rotor assembly and a stator assembly, the rotor assembly includes a coil and a motor shaft, the stator assembly includes a magnetic steel assembly, the magnetic steel assembly is sleeved on the motor shaft, the motor shaft passes through the coil, and the motor shaft can drive the coil to rotate relative to the magnetic steel assembly with the central axis of the motor shaft as the rotation axis, the polarity of the magnetic steel assembly is arranged according to a Halbach array combination, and the magnetic force lines at both ends of the magnetic steel assembly along the central axis of the motor shaft constrain the magnetic force lines of the magnetic steel assembly in the middle of the central axis of the motor shaft within the effective area cut by the magnetic force lines of the coil.

[0005] Compared with the prior art, the polarity of the magnetic steel assembly of the present invention is arranged in a Halbach array combination, and the magnetic lines of force at both ends of the magnetic steel assembly along the central axis of the motor shaft constrain the magnetic lines of force in the middle of the magnetic steel assembly along the central axis of the motor shaft within the effective area cut by the magnetic lines of force of the coil. The magnetic poles of the magnetic steel assembly are arranged in a diversified manner by a Halbach array combination arrangement, so that the magnetic field strength of the magnetic steel assembly is distributed axially and the radial magnetic field is concentrated and constrained within the effective area cut by the magnetic lines of force of the coil, effectively reducing the portion of the magnetic lines of force of the magnetic steel assembly falling into the invalid area cut by the magnetic lines of force of the coil, and effectively reducing the excess magnetic field rate, thereby achieving the performance of the hollow cup motor effectively improved without increasing the weight of the magnetic steel and the outer diameter of the motor, so as to meet the high-performance manufacturing requirements of the micro motor.

[0006] Preferably, the magnetic steel assembly is arranged in an annular cylindrical shape, and the magnetic steel assembly is arranged in multiple sections along the central axis direction of the motor shaft.

[0007] Specifically, the magnetic steel assembly includes a first constrained magnetic steel, an effective magnetic steel, and a second constrained magnetic steel connected in sequence, the first constrained magnetic steel and the second constrained magnetic steel are respectively arranged in a circular ring shape, the effective magnetic steel is arranged in a ring-shaped cylindrical shape, the first constrained magnetic steel includes a first semi-circular ring magnetic steel and a second semi-circular ring magnetic steel, the first semi-circular ring magnetic steel and the second semi-circular ring magnetic steel are butt-connected to form the first constrained magnetic steel, the second constrained magnetic steel includes a third semi-circular ring magnetic steel and a fourth semi-circular ring magnetic steel, the third semi-circular ring magnetic steel and the fourth semi-circular ring magnetic steel are butt-connected to form the second constrained magnetic steel, the first semi-circular ring magnetic steel and the third semi-circular ring magnetic steel are respectively arranged at the two ends of the radial upper half of the effective magnetic steel along the central axis direction of the motor shaft, and the second semi-circular ring magnetic steel and the fourth semi-circular ring magnetic steel are respectively arranged at the two ends of the radial lower half of the effective magnetic steel along the central axis direction of the motor shaft.

[0008] Specifically, the polarity of the radial upper half and the radial lower half of the effective magnetic steel along the central axis of the motor shaft are opposite;

[0009] The polarities of one end of the first semicircular ring magnetic steel and the third semicircular ring magnetic steel close to the radial upper half of the effective magnetic steel along the central axis of the motor shaft are respectively consistent with the polarities of the radial upper half of the effective magnetic steel along the central axis of the motor shaft;

[0010] The polarities of one end of the first semicircular ring magnetic steel and the third semicircular ring magnetic steel away from the radial upper half of the effective magnetic steel along the central axis of the motor shaft are respectively opposite to the polarity of the radial upper half of the effective magnetic steel along the central axis of the motor shaft;

[0011] The polarities of one end of the second semicircular ring magnetic steel and the fourth semicircular ring magnetic steel close to the radial lower half of the effective magnetic steel along the central axis of the motor shaft are respectively consistent with the polarities of the radial lower half of the effective magnetic steel along the central axis of the motor shaft;

[0012] The polarities of one end of the second semicircular ring magnetic steel and the fourth semicircular ring magnetic steel away from the radial lower half of the effective magnetic steel along the central axis of the motor shaft are opposite to the polarity of the radial lower half of the effective magnetic steel along the central axis of the motor shaft.

[0013] Preferably, the projection of the effective magnetic steel along a direction perpendicular to the central axis of the motor shaft completely falls within the effective area cut by the magnetic lines of force of the coil.

[0014] Specifically, the projection of the effective magnetic steel along the direction perpendicular to the central axis of the motor shaft completely falls within the projection of the coil along the direction perpendicular to the central axis of the motor shaft.

[0015] Preferably, the length of the effective magnetic steel along the direction perpendicular to the central axis of the motor shaft is equal to the length of the coil along the direction perpendicular to the central axis of the motor shaft.

[0016] Preferably, the length of the effective magnetic steel along the central axis of the motor shaft is respectively greater than the length of the first constrained magnetic steel and the second constrained magnetic steel along the central axis of the motor shaft;

[0017] The length of the first constrained magnetic steel along the central axis of the motor shaft is equal to the length of the second constrained magnetic steel along the central axis of the motor shaft.

[0018] Preferably, the magnetic steel assembly is arranged in an annular cylindrical shape, and the magnetic steel assembly includes a plurality of magnetic steel monomers, and all the magnetic steel monomers together form the magnetic steel assembly along the radial direction of the motor shaft.

[0019] Preferably, the stator assembly also includes a casing with an opening at one end and an end cover for covering the open end of the casing, the coil is located in the casing, and the rotor assembly also includes a bearing and a bearing sleeve, the bearing is fixedly connected to the casing, at least two of the bearings are sleeved on the motor shaft with intervals, the bearing sleeve is sleeved on the motor shaft through all bearings, the magnetic steel assembly is sleeved on the motor shaft through the bearing sleeve, there is a gap between the magnetic steel assembly and the coil, one end of the motor shaft is rotatably connected to the end cover, and the other end can rotatably pass through the sealed end of the casing, and the motor shaft rotates to drive the coil to rotate synchronously.

[0020] Preferably, the rotor assembly also includes a vibrator, a commutator assembly, a brush assembly and a wire. The vibrator is arranged in an eccentric structure. The vibrator is arranged at one end of the motor shaft passing through the sealed end of the casing. The motor shaft is rotatably connected to the end cover through the commutator assembly. The coil is connected to the commutator assembly. The brush assembly is arranged in the end cover. The two wires pass through the end covers respectively, and one of the two wires is electrically connected to the positive end of the coil, and the other is electrically connected to the negative end of the coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the coreless cup motor of the present invention;

[0022] Figure 2 yes Figure 1 Schematic diagram of the decomposition of

[0023] Figure 3 yes Figure 1 A cross-sectional view of

[0024] Figure 4 is an exploded schematic diagram of the magnetic steel assembly of the present invention;

[0025] Figure 5 is a schematic diagram of the magnetic force line distribution of the magnetic steel assembly of the present invention;

[0026] Figure 6 It is a schematic diagram of the position state of the magnetic steel assembly and the coil of the present invention;

[0027] Figure 7 It is a polarity distribution diagram when the magnetic steel assembly of the present invention is arranged in two sections along the central axis direction of the motor shaft;

[0028] Figure 8 It is a polarity distribution diagram when the magnetic steel assembly of the present invention is arranged in four sections along the central axis direction of the motor shaft;

[0029] Fig. 9 It is a polarity distribution diagram when the magnetic steel assembly of the present invention is arranged in five sections along the central axis direction of the motor shaft. DETAILED DESCRIPTION

[0030] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, the following is a detailed description in conjunction with the implementation methods and the accompanying drawings.

[0031] See also Figure 1-Figure 3As shown, the hollow cup motor of this embodiment includes a stator assembly and a rotor assembly, wherein the rotor assembly includes a coil 11 and a motor shaft 21, and the stator assembly includes a magnetic steel assembly 22, which is sleeved on the motor shaft 21. The motor shaft 21 passes through the coil 11, and the motor shaft 21 can drive the coil 11 to rotate relative to the magnetic steel assembly 22 with the central axis of the motor shaft 21 as the rotation axis. By changing the direction and magnitude of the current flowing through the coil 11, the speed adjustment and forward and reverse rotation adjustment of the hollow cup motor can be achieved.

[0032] It can be understood that the coil 11 of the present embodiment is a coil 11 of a hexagonal annular column structure. Of course, in other embodiments, the coil 11 may be a coil 11 of other polygonal annular column structures, which is not limited here.

[0033] The polarity of the magnetic steel assembly 22 is arranged in a Halbach array, and the magnetic lines of force at both ends of the magnetic steel assembly 22 along the central axis of the motor shaft 21 constrain the magnetic lines of force in the middle of the magnetic steel assembly 22 along the central axis of the motor shaft 21 within the effective area cut by the magnetic lines of force of the coil 11. The Halbach array is a magnetic structure, which is an approximately ideal structure in engineering, and the goal is to use the least amount of magnets to generate the strongest magnetic field. This embodiment uses the Halbach array to concentrate most of the magnetic lines of force of the magnetic steel assembly 22 within the effective area cut by the magnetic lines of force of the coil 11, so as to reduce the magnetic lines of force of the magnetic steel assembly 22 falling into the invalid area cut by the magnetic lines of force of the coil 11, so as to increase the magnetic line efficiency of the magnetic steel assembly 22 under the same volume, thereby effectively improving the performance of the hollow cup motor without increasing the weight of the magnetic steel and the outer diameter of the motor, so as to meet the high-performance manufacturing requirements of the micro motor.

[0034] It should be noted that magnets generally refer to aluminum-nickel-cobalt alloys (AlNiCo is the abbreviation of aluminum-nickel-cobalt in English). Magnets are made of several hard and strong metals, such as iron, aluminum, nickel, cobalt, etc., and sometimes copper, niobium, and tantalum. They are used to make super-hard permanent magnet alloys. Magnets can generate magnetic lines of force (also called magnetic fields). Magnetic lines of force are a virtual physical concept that refers to the field that transmits magnetic forces between real objects. The magnetic field has the radiation characteristics of waves and particles. There is a magnetic field around the magnet, and the interaction between magnets is mediated by the magnetic field, so the two magnets can act without physical contact.

[0035] See also Figure 4 and Figure 5As shown, the magnetic steel assembly 22 of this embodiment is arranged in an annular cylindrical shape, and the magnetic steel assembly 22 is arranged in three sections along the central axis direction of the motor shaft 21. The magnetic steel assembly 22 includes a first constrained magnetic steel 221, an effective magnetic steel 222, and a second constrained magnetic steel 223 connected in sequence. The first constrained magnetic steel 221, the effective magnetic steel 222, and the second constrained magnetic steel 223 are independently manufactured magnetic blocks, and are sequentially bonded to form a magnetic steel assembly 22 of an integrated structure.

[0036] The first constrained magnetic steel 221 and the second constrained magnetic steel 223 are respectively arranged in a circular ring shape, and the effective magnetic steel 222 is arranged in a ring cylindrical shape. The first constrained magnetic steel 221 includes a first semi-circular ring magnetic steel 2211 and a second semi-circular ring magnetic steel 2212. The first semi-circular ring magnetic steel 2211 and the second semi-circular ring magnetic steel 2212 are butt-jointed to form the first constrained magnetic steel 221. Accordingly, the first semi-circular ring magnetic steel 2211 and the second semi-circular ring magnetic steel 2212 are independently manufactured magnetic blocks, and are butt-jointed and bonded to form the first constrained magnetic steel 221 of an integrated structure.

[0037] The second constrained magnetic steel 223 includes a third semi-circular ring magnetic steel 2231 and a fourth semi-circular ring magnetic steel 2232, and the third semi-circular ring magnetic steel 2231 and the fourth semi-circular ring magnetic steel 2232 are butt-jointed to form the second constrained magnetic steel 223. Accordingly, the third semi-circular ring magnetic steel 2231 and the fourth semi-circular ring magnetic steel 2232 are independently manufactured magnetic blocks, and are butt-jointed and bonded to form the second constrained magnetic steel 223 of an integrated structure.

[0038] The first semicircular magnetic steel 2211 and the third semicircular magnetic steel 2231 are respectively arranged at the two ends of the radial upper half of the effective magnetic steel 222 along the central axis direction of the motor shaft 21 by bonding, and the second semicircular magnetic steel 2212 and the fourth semicircular magnetic steel 2232 are respectively arranged at the two ends of the radial lower half of the effective magnetic steel 222 along the central axis direction of the motor shaft 21 by bonding.

[0039] Specifically, the polarity of the radial upper half and the radial lower half of the effective magnetic steel 222 along the central axis of the motor shaft 21 are opposite. In this embodiment, the polarity of the radial upper half of the effective magnetic steel 222 along the central axis of the motor shaft 21 is N pole, and the polarity of the radial lower half of the effective magnetic steel 222 along the central axis of the motor shaft 21 is S pole.

[0040] The polarities of one end of the first semicircular magnetic steel 2211 and the third semicircular magnetic steel 2231 close to the radial upper half of the effective magnetic steel 222 along the central axis of the motor shaft 21 are respectively consistent with the polarity of the radial upper half of the effective magnetic steel 222 along the central axis of the motor shaft 21. In this embodiment, the polarities of one end of the first semicircular magnetic steel 2211 and the third semicircular magnetic steel 2231 close to the radial upper half of the effective magnetic steel 222 along the central axis of the motor shaft 21 are both N poles.

[0041] The polarities of one end of the first semicircular magnetic steel 2211 and the third semicircular magnetic steel 2231 away from the radial upper half of the effective magnetic steel 222 along the central axis of the motor shaft 21 are opposite to the polarity of the radial upper half of the effective magnetic steel 222 along the central axis of the motor shaft 21. In this embodiment, the polarities of one end of the first semicircular magnetic steel 2211 and the third semicircular magnetic steel 2231 away from the radial upper half of the effective magnetic steel 222 along the central axis of the motor shaft 21 are both S poles.

[0042] The polarities of one end of the second semicircular magnetic steel 2212 and the fourth semicircular magnetic steel 2232 close to the radial lower half of the effective magnetic steel 222 along the central axis of the motor shaft 21 are respectively consistent with the polarity of the radial lower half of the effective magnetic steel 222 along the central axis of the motor shaft 21. In this embodiment, the polarities of one end of the second semicircular magnetic steel 2212 and the fourth semicircular magnetic steel 2232 close to the radial lower half of the effective magnetic steel 222 along the central axis of the motor shaft 21 are both S poles.

[0043] The polarities of one end of the second semicircular magnetic steel 2212 and the fourth semicircular magnetic steel 2232 away from the radial lower half of the effective magnetic steel 222 along the central axis of the motor shaft 21 are opposite to the polarity of the radial lower half of the effective magnetic steel 222 along the central axis of the motor shaft 21. In this embodiment, the polarities of one end of the second semicircular magnetic steel 2212 and the fourth semicircular magnetic steel 2232 away from the radial lower half of the effective magnetic steel 222 along the central axis of the motor shaft 21 are both N poles.

[0044] Through the above arrangement, the magnetic force lines distribution of the magnetic steel assembly 22 is as follows: Figure 5 As shown, since the magnetic lines of force have the characteristics of a closed loop and never intersecting, the magnetic lines of force generated by the annular outer wall of the effective magnetic steel 222 at this time can be constrained by the magnetic lines of force generated by the annular outer walls of the first constraining magnetic steel 221 and the second constraining magnetic steel 223, respectively, and then diffuse outward after being concentrated and constrained in the radial direction of the effective magnetic steel 222. Since the coil 11 is generally adjacent to the magnetic steel assembly 22, the relative positions of the magnetic steel assembly 22 and the coil 11 are reasonably set, so that the area where the magnetic lines of force generated by the effective magnetic steel 222 are concentrated and constrained can completely fall into the effective area cut by the magnetic lines of force of the coil 11, thereby theoretically achieving the maximum utilization rate of the magnetic lines of force of the effective magnetic steel 222.

[0045] It is worth noting that in other preferred embodiments, the polarity of the radial upper half of the effective magnetic steel 222 along the central axis of the motor shaft 21 is an S pole, and the polarity of the radial lower half of the effective magnetic steel 222 along the central axis of the motor shaft 21 is an N pole. At this time, the polarities of the first semicircular ring magnetic steel 2211, the second semicircular ring magnetic steel 2212, the third semicircular ring magnetic steel 2231 and each part of the third semicircular ring magnetic steel 2231 need to be modified accordingly, which will not be elaborated here.

[0046] It should be noted that magnetization can magnetize magnetic materials or increase the magnetism of magnets with insufficient magnetism. Generally, the magnetic object to be magnetized is placed in the magnetic field formed by the coil 11 through which direct current passes to perform the magnetization operation. In addition, the magnetization method of all magnetic steels in this embodiment is unidirectional magnetization.

[0047] See also Figure 6 As shown, in order to achieve the maximum utilization rate of the magnetic lines of force of the effective magnetic steel 222 in theory, the relative position of the magnetic steel assembly 22 and the coil 11 is further optimized in this embodiment:

[0048] Specifically, the projection of the effective magnetic steel 222 along the direction perpendicular to the central axis of the motor shaft 21 completely falls within the effective area cut by the magnetic lines of force of the coil 11, so that the area where the magnetic lines of force generated by the effective magnetic steel 222 are concentratedly constrained completely falls within the effective area cut by the magnetic lines of force of the coil 11, thereby theoretically achieving a utilization rate of the magnetic lines of force of the effective magnetic steel 222 close to 100%.

[0049] Furthermore, the projection of the effective magnetic steel 222 along the direction perpendicular to the central axis of the motor shaft 21 completely falls within the projection of the coil 11 along the direction perpendicular to the central axis of the motor shaft 21. It has been experimentally measured that the effective area cut by the magnetic lines of force of the coil 11 made by a specific winding method can be close to 100%. At this time, the effective area cut by the magnetic lines of force of the coil 11 is the projection of the coil 11 along the direction perpendicular to the central axis of the motor shaft 21, and the projection of the effective magnetic steel 222 along the direction perpendicular to the central axis of the motor shaft 21 completely falls within the projection of the coil 11 along the direction perpendicular to the central axis of the motor shaft 21. Specifically, Figure 6 It shows that when the length of the effective magnetic steel 222 along the central axis direction of the motor shaft 21 is equal to the length of the coil 11 along the central axis direction of the motor shaft 21, the beneficial effect of maximizing the utilization rate of the effective area of ​​the magnetic line cutting can be obtained. At this time, the projections of the first constrained magnetic steel 221 and the second constrained magnetic steel 223 along the central axis direction of the motor shaft 21 are respectively located outside the projection of the coil 11 along the central axis direction of the motor shaft 21.

[0050] Furthermore, in order to further reduce the overall length of the coreless motor of this embodiment along the central axis of the motor shaft 21, the length of the effective magnetic steel 222 along the central axis of the motor shaft 21 is respectively greater than the length of the first constrained magnetic steel 221 and the second constrained magnetic steel 223 along the central axis of the motor shaft 21. In fact, the proportion of the length of the effective magnetic steel 222 along the central axis of the motor shaft 21 should be as large as possible. On the premise of ensuring that the first constrained magnetic steel 221 and the second constrained magnetic steel 223 can concentrate the magnetic lines of force generated by the effective magnetic steel 222 in the radial direction of the effective magnetic steel 222 and then diffuse outward, the length of the first constrained magnetic steel 221 and the second constrained magnetic steel 223 along the central axis of the motor shaft 21 should be reduced as much as possible to reduce the overall length of the coreless motor along the central axis of the motor shaft 21.

[0051] See also Figure 1-Figure 3 As shown, the stator assembly of this embodiment also includes a casing 23 with an opening at one end and an end cover 24 for covering the open end of the casing 23. The coil 11 is installed in the casing 23. The rotor assembly also includes a bearing 23 and a bearing sleeve 13. At least two bearings 23 are sleeved on the motor shaft 21 at intervals. The bearing sleeve 13 is arranged on the motor shaft 21 through all the bearing sleeves 13. The magnetic steel assembly 22 is sleeved on the motor shaft 21 through the bearing sleeve 13. There is a gap between the magnetic steel assembly 22 and the coil 11. One end of the motor shaft 21 is rotatably connected to the end cover 24, and the other end can be rotatably passed through the sealed end of the casing 23.

[0052] Preferably, the rotor assembly further includes a vibrator 14, a commutator assembly 15, a brush assembly 16 and a wire 17. The vibrator 14 is arranged in an eccentric structure. The vibrator 14 is arranged at one end of the sealed end of the motor shaft 21 passing through the housing 23 by riveting. The motor shaft 21 is connected to the end cover 24 by rotation through the commutator assembly 15. The coil 11 is bonded and fixed to the commutator assembly 15. When the motor shaft 21 rotates, the coil 11 and the commutator assembly 15 are driven to rotate synchronously. The brush assembly 16 is arranged in the end cover 24 by embedding. Two wires 17 pass through the end cover 24 respectively, and one of the two wires 17 is electrically connected to the positive terminal of the brush assembly 16, and the other is electrically connected to the negative terminal of the brush assembly 16.

[0053] It is worth noting that the magnetic steel assembly 22 of the present embodiment is arranged in three sections along the central axis direction of the motor shaft 21. In other preferred embodiments, the magnetic steel assembly 22 is arranged in two sections, four sections or five sections along the central axis direction of the motor shaft 21. Figure 7-Figure 9Polarity distribution diagrams are given when the magnetic steel assembly 22 is arranged in two sections, four sections and five sections along the central axis of the motor shaft 21. On the premise of ensuring that the magnetic force lines generated by the magnetic steel assembly 22 can concentrate most of the magnetic force lines of the magnetic steel assembly 22 in the effective area cut by the magnetic force lines of the coil 11, so as to reduce the magnetic force lines of the magnetic steel assembly 22 falling into the invalid area cut by the magnetic force lines of the coil 11, and to increase the magnetic force line efficiency of the magnetic steel assembly 22 under the same volume, the number of sections of the magnetic steel assembly 22 along the central axis of the motor shaft 21 is not limited.

[0054] Furthermore, in other preferred embodiments, the magnetic steel assembly 22 is arranged in an annular cylindrical shape, and the magnetic steel assembly 22 includes a plurality of magnetic steel monomers, all of which together form the magnetic steel assembly 22 along the radial direction of the motor shaft 21, so as to produce an effect in which the magnetic lines of force at both ends of the magnetic steel assembly 22 along the central axis direction of the motor shaft 21 constrain the magnetic lines of force in the middle part of the magnetic steel assembly 22 along the central axis direction of the motor shaft 21 to be within the effective area cut by the magnetic lines of force of the coil 11.

[0055] Combination Figure 1-Figure 9 The polarity of the magnetic steel component 22 of the present invention is arranged in a Halbach array combination, and the magnetic lines of force at both ends of the magnetic steel component 22 along the central axis direction of the motor shaft 21 constrain the magnetic lines of force in the middle of the magnetic steel component 22 along the central axis direction of the motor shaft 21 within the effective area cut by the magnetic lines of force of the coil 11. The magnetic poles of the magnetic steel component 22 are arranged in a diversified manner by a Halbach array combination arrangement, so that the magnetic field strength of the magnetic steel component 22 is distributed axially and the radial magnetic field is concentrated and constrained within the effective area cut by the magnetic lines of force of the coil 11, effectively reducing the portion of the magnetic lines of force of the magnetic steel component 22 falling into the invalid area cut by the magnetic lines of force of the coil 11, and effectively reducing the excess magnetic field rate, thereby achieving the performance of the hollow cup motor without increasing the weight of the magnetic steel and the outer diameter of the motor, so as to meet the high-performance manufacturing requirements of the micro motor.

[0056] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A coreless motor, comprising a rotor assembly and a stator assembly, wherein the rotor assembly comprises a coil and a motor shaft, and the stator assembly comprises a magnetic steel assembly, wherein the magnetic steel assembly is sleeved on the motor shaft, the motor shaft passes through the coil, and the motor shaft can drive the coil to rotate relative to the magnetic steel assembly with the central axis of the motor shaft as the rotation axis, characterized in that: The polarity of the magnetic steel assembly is arranged in a Halbach array combination, and the magnetic force lines at both ends of the magnetic steel assembly along the central axis of the motor shaft constrain the magnetic force lines of the magnetic steel assembly in the middle of the central axis of the motor shaft within the effective area cut by the magnetic force lines of the coil; The magnetic steel assembly is arranged in an annular cylindrical shape, and the magnetic steel assembly is arranged in multiple sections along the central axis direction of the motor shaft; The magnetic steel assembly includes a first constrained magnetic steel, an effective magnetic steel, and a second constrained magnetic steel connected in sequence, the first constrained magnetic steel and the second constrained magnetic steel are respectively arranged in a circular ring shape, the effective magnetic steel is arranged in a ring-shaped cylindrical shape, the first constrained magnetic steel includes a first semicircular ring magnetic steel and a second semicircular ring magnetic steel, the first semicircular ring magnetic steel and the second semicircular ring magnetic steel are butt-connected to form the first constrained magnetic steel, the second constrained magnetic steel includes a third semicircular ring magnetic steel and a fourth semicircular ring magnetic steel, the third semicircular ring magnetic steel and the fourth semicircular ring magnetic steel are butt-connected to form the second constrained magnetic steel, the first semicircular ring magnetic steel and the third semicircular ring magnetic steel are respectively arranged at two ends of the radial upper half of the effective magnetic steel along the central axis direction of the motor shaft, and the second semicircular ring magnetic steel and the fourth semicircular ring magnetic steel are respectively arranged at two ends of the radial lower half of the effective magnetic steel along the central axis direction of the motor shaft; The polarity of the radial upper half and the radial lower half of the effective magnetic steel along the central axis of the motor shaft are opposite; The polarities of one end of the first semicircular ring magnetic steel and the third semicircular ring magnetic steel close to the radial upper half of the effective magnetic steel along the central axis of the motor shaft are respectively consistent with the polarities of the radial upper half of the effective magnetic steel along the central axis of the motor shaft; The polarities of one end of the first semicircular ring magnetic steel and the third semicircular ring magnetic steel away from the radial upper half of the effective magnetic steel along the central axis of the motor shaft are opposite to the polarity of the radial upper half of the effective magnetic steel along the central axis of the motor shaft; The polarities of one end of the second semicircular ring magnetic steel and the fourth semicircular ring magnetic steel close to the radial lower half of the effective magnetic steel along the central axis of the motor shaft are respectively consistent with the polarities of the radial lower half of the effective magnetic steel along the central axis of the motor shaft; The polarities of one end of the second semicircular ring magnetic steel and the fourth semicircular ring magnetic steel away from the radial lower half of the effective magnetic steel along the central axis of the motor shaft are opposite to the polarity of the radial lower half of the effective magnetic steel along the central axis of the motor shaft.

2. The coreless motor according to claim 1, characterized in that: The projection of the effective magnetic steel along a direction perpendicular to the central axis of the motor shaft completely falls within the effective area cut by the magnetic lines of force of the coil.

3. The coreless motor according to claim 2, characterized in that: The projection of the effective magnetic steel along the direction perpendicular to the central axis of the motor shaft completely falls within the projection of the coil along the direction perpendicular to the central axis of the motor shaft.

4. The coreless motor according to claim 1, characterized in that: The length of the effective magnetic steel along the central axis of the motor shaft is respectively greater than the length of the first constrained magnetic steel and the second constrained magnetic steel along the central axis of the motor shaft; The length of the first constrained magnetic steel along the central axis of the motor shaft is equal to the length of the second constrained magnetic steel along the central axis of the motor shaft.

5. The coreless motor according to claim 1, characterized in that: The magnetic steel assembly is arranged in an annular cylindrical shape, and the magnetic steel assembly includes a plurality of magnetic steel monomers, and all the magnetic steel monomers together form the magnetic steel assembly along the radial direction of the motor shaft.

6. The coreless motor according to claim 1, characterized in that: The stator assembly also includes a casing with an opening at one end and an end cover for covering the open end of the casing. The coil is located in the casing. The rotor assembly also includes a bearing and a bearing sleeve. The bearing is fixedly connected to the casing. At least two of the bearings are sleeved on the motor shaft at intervals. The bearing sleeve is sleeved on the motor shaft through all the bearings. The magnetic steel assembly is sleeved on the motor shaft through the bearing sleeve. There is a gap between the magnetic steel assembly and the coil. One end of the motor shaft is rotatably connected to the end cover, and the other end can rotatably pass through the sealed end of the casing. The motor shaft rotates to drive the coil to rotate synchronously.

7. The coreless motor according to claim 6, characterized in that: The rotor assembly also includes a vibrator, a commutator assembly, a brush assembly and a conductor. The vibrator is arranged in an eccentric structure. The vibrator is arranged at one end of the motor shaft passing through the sealed end of the housing. The motor shaft is rotatably connected to the end cover through the commutator assembly. The coil is connected to the commutator assembly. The brush assembly is arranged in the end cover. The two conductors pass through the end covers respectively, and one of the two conductors is electrically connected to the positive terminal of the brush assembly, and the other is electrically connected to the negative terminal of the brush assembly.

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