CN218733797U

CN218733797U - Brushless motor

Info

Publication number: CN218733797U
Application number: CN202223030740.9U
Authority: CN
Inventors: 谢小五; 陈亮; 张宏亮; 江远
Original assignee: Guangdong Zhaoqing L&V Co Ltd
Current assignee: Guangdong Zhaoqing L&V Co Ltd
Priority date: 2022-11-15
Filing date: 2022-11-15
Publication date: 2023-03-24
Anticipated expiration: 2032-11-15

Abstract

The utility model discloses a brushless motor, including rotor subassembly, stator module and hall sensor, the rotor subassembly includes rotor core and the permanent magnet of setting on rotor core, and stator module includes stator core and stator winding, and hall sensor sets up towards the axial terminal surface of rotor subassembly, its characterized in that, and the axial dimension of permanent magnet is greater than the axial dimension of stator core and rotor core, surpasss the part and is used for providing the magnetic flux to hall sensor. The rotor permanent magnet is used as the Hall sensor magnet to provide magnetic flux for the Hall sensor, the traditional two magnets of the Hall sensor magnet and the rotor permanent magnet are replaced, the procedures of uniformly magnetizing the Hall sensor magnet and the rotor permanent magnet and adjusting the relative positions of the two magnets are omitted, the process complexity is reduced, the magnetic flux consistency of the rotor magnet is greatly improved, and therefore the rotor position detection accuracy and precision are correspondingly improved. In addition, only one magnet needs to be installed, so that the installation is convenient.

Description

Brushless motor

Technical Field

The utility model relates to a brushless motor field particularly, relates to a simple process, convenient operation and high brushless motor of rotor position detection precision.

Background

The brushless motor mainly comprises a stator assembly, a rotor assembly and a controller. The stator assembly comprises a stator core and a stator winding. The stator core is generally formed by laminating silicon steel sheets, and the inner circular surface of the stator core is provided with slots for arranging stator windings. The rotor assembly of the brushless motor includes a rotor core and a permanent magnet disposed on the rotor core.

After the stator winding of the brushless motor is powered on, the current in the winding coil can generate a corresponding magnetic field, and the magnetic field interacts with the rotor permanent magnet to drive the rotor to rotate. In short, the rotor permanent magnet has a movement tendency that the direction of the magnetic induction line inside the rotor permanent magnet is consistent with the direction of the magnetic induction line outside the rotor permanent magnet as much as possible, that is, the N pole of the rotor permanent magnet and the S pole of the energized winding have a movement tendency of being aligned, and the S pole of the rotor permanent magnet and the N pole of the energized winding have a movement tendency of being aligned, so that a rotation torque is formed on the rotor, and the rotor rotates under the action of the rotation torque.

In order to drive the rotor to rotate continuously, the magnetic field direction of the stator winding needs to be adjusted continuously according to the current position of the rotor. Energizing the coils of the stator windings in a sequence based on the position of the rotor poles relative to the stator windings generates a rotating magnetic field, thereby driving the rotor to rotate continuously. The position of the rotor is usually detected by a position sensor which detects the position of the rotor poles relative to the stator windings and generates position-sensing signals at the determined positions, which are converted for controlling the current switching of the stator windings. Therefore, the control of the brushless motor is characterized in that the position of the rotor is detected, and the phase change point of the brushless motor is obtained according to the position information of the rotor.

At present, the commonly used rotor position detection method includes two modes of hall sensor detection and sensorless detection. Sensors that utilize the hall effect are referred to as hall sensors. When a current passes through the semiconductor perpendicular to an external magnetic field, carriers are deflected, an additional electric field is generated in a direction perpendicular to the current and the magnetic field, so that a potential difference is generated across the semiconductor, the potential difference is called a hall voltage, and the generated phenomenon is called a hall effect. The Hall voltage changes along with the change of the magnetic field intensity, the stronger the magnetic field, the higher the voltage, the weaker the magnetic field, and the lower the voltage. Because the rotor of the brushless motor is a permanent magnet, the change of the magnetic field intensity of the rotor can be obtained through the change of the Hall voltage by only installing the Hall sensor at a proper position, and then the rotating position of the rotor can be obtained.

The rotor structure of the existing brushless motor is that a rotor permanent magnet and a stator iron core are designed to have the same height or the same axial dimension, and then a magnet is additionally arranged on a rotor to be used as a Hall sensor magnet to provide magnetic flux for the Hall sensor. This method and structure suffers from the following disadvantages: the main flux on the rotor permanent magnet and the flux of the magnet providing the flux for the hall sensor have angular deviations, which can lead to a reduction in the accuracy and precision of the rotor position detection. In addition, the additional addition of magnets to the rotor can lead to complexity in the motor assembly process. In order to eliminate the deviation of the installation angle of the two magnets, it is common practice to magnetize both magnets simultaneously or to perform angle compensation and calibration by electronic techniques after magnetizing the magnets separately, which affects the operability of motor assembly and increases the process complexity.

Therefore, there is a need for a brushless motor and a method for detecting a rotor position of a brushless motor, which have a simple process, are convenient to operate, and have high position detection accuracy.

Disclosure of Invention

In order to solve the above problems, the utility model provides a brushless motor and brushless motor rotor position detection method not only reduces the complexity of magnetizing with mounting process, improves rotor permanent magnet's magnetic flux uniformity moreover, improves rotor position detection accuracy and precision.

The purpose of the utility model is realized through the following technical scheme: the brushless motor comprises a rotor assembly, a stator assembly and a Hall sensor, wherein the rotor assembly comprises a rotor core and a permanent magnet arranged on the rotor core, the stator assembly comprises a stator core and a stator winding, and the Hall sensor faces to the axial end face of the rotor assembly.

According to an aspect of the utility model, the axial dimension of permanent magnet is greater than stator core with rotor core's axial dimension, surpass the part be used for to hall sensor provides the magnetic flux.

According to an aspect of the invention, the dimension of the excess portion is 2-8 mm.

According to an aspect of the present invention, the axial dimension of the rotor core is the same as the axial dimension of the stator core.

According to an aspect of the present invention, the permanent magnet is a circular magnet ring. The magnet ring can be arranged in other conventional modes besides the circular magnet ring, such as a magnetic sheet type, a surface-mounted type, a buried type or a built-in type.

According to the utility model discloses an aspect, the mode of magnetizing of permanent magnet is radial magnetization, distance permanent magnet axial terminal surface 2 millimeters department magnetic leakage magnetic flux is not less than 200 gauss.

According to an aspect of the utility model, brushless motor is the three-phase brushless DC motor of inner rotor structure.

According to an aspect of the utility model, brushless motor includes printed circuit board, hall sensor sets up on the printed circuit board.

According to an aspect of the invention, the axial end face distance of the excess part is 1-2.5 mm from the hall sensor.

According to one aspect of the present invention, the stator core has a circular shape, an outer diameter of 20 to 60 mm, and an inner diameter of 10 to 50 mm.

According to one aspect of the present invention, the stator core has a hexagonal shape, the opposite sides of the hexagonal shape have a dimension of 20 to 60 mm, and the inner diameter has a dimension of 10 to 50 mm.

The utility model discloses a brushless motor uses rotor permanent magnet itself to provide the magnetic flux as hall sensor magnet to hall sensor, replaces the hall sensor magnet that adds in addition in the tradition, has saved the process of unified magnetizing and two magnet relative positions of adjustment for hall sensor magnet and rotor permanent magnet, reduces technology complexity. And the consistency of the magnetic flux of the rotor permanent magnet is greatly improved compared with the consistency of the magnetic flux of the two magnets, so that the accuracy and precision of the rotor position detection are correspondingly improved. In addition, only one magnet needs to be installed, so that the installation is convenient.

The utility model discloses still disclose a brushless motor rotor position detection method, brushless motor includes rotor subassembly, stator module and hall sensor, the rotor subassembly includes rotor core and sets up permanent magnet on the rotor core, stator module includes stator core and stator winding, its characterized in that, the method includes: the Hall sensor is arranged facing to the axial end face of the rotor assembly; a portion of the permanent magnet is used to provide magnetic flux to the hall sensor.

According to the utility model discloses an aspect sets up the axial dimension of permanent magnet is greater than stator core with rotor core's axial dimension, surpasss the part and is used for doing hall sensor provides the magnetic flux.

The utility model discloses a brushless motor rotor position detection method provides the magnetic flux to hall sensor through using rotor permanent magnet itself as hall sensor magnet, replaces the hall sensor magnet that adds in addition traditionally, has saved the process of unified magnetizing and two magnet relative positions of adjustment for hall sensor magnet and rotor permanent magnet, reduces the technology complexity. In addition, the consistency of the magnetic flux of the rotor permanent magnet is greatly improved compared with the consistency of the magnetic flux of the two magnets, so that the accuracy and precision of the rotor position detection are correspondingly improved.

Drawings

FIG. 1 is a schematic diagram of a rotor structure and a rotor position detection method of a brushless motor in the prior art;

fig. 2 is a schematic view of a rotor structure of a brushless motor and a rotor position detection method according to an embodiment of the present invention;

FIG. 3 is an end view of the rotor ring of FIG. 2;

fig. 4 is a schematic diagram illustrating axial dimensional relationships of a rotor core and a stator core of a brushless motor according to an embodiment of the present invention;

fig. 5 is an end view of a brushless motor stator core according to an embodiment of the present invention;

fig. 6 is an end view of a brushless motor stator core according to another embodiment of the present invention.

Detailed Description

The brushless motor and the method for detecting the rotor position of the brushless motor according to the present invention will be described in further detail with reference to the accompanying drawings, which show, by way of example, embodiments of the present invention.

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention to a user of ordinary skill in the art. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. Furthermore, it is to be understood that the invention is not to be limited to the specific embodiments described. Rather, any combination of the following features and elements, whether related to different embodiments or not, is contemplated to implement the present invention. Thus, the following aspects, features, embodiments and advantages are merely illustrative and should not be considered elements or limitations of the claims except where explicitly recited in a claim.

Referring to fig. 1, fig. 1 is a schematic diagram of a rotor structure and a rotor position detection method of a brushless motor in the prior art. Wherein the rotor assembly comprises a rotor shaft 1 and a rotor core 2 and rotor permanent magnets 3' arranged on the rotor shaft 1. The hall sensor 5 is disposed on the printed circuit board 4 facing an axial end face of the rotor assembly. In order to provide magnetic flux for detecting the current position of the rotor to the hall sensor 5, a permanent magnet is additionally arranged on the rotor shaft 1 to serve as a hall sensor magnet 6 for providing magnetic flux to the hall sensor 5. A spacer, typically made of stainless steel or the like, is provided between the rotor permanent magnet 3' and the hall sensor magnet 6 to eliminate the mutual influence between the end-face magnetic fields of the two magnets.

Since the main flux on the rotor permanent magnet 3' and the flux of the hall sensor magnet 6 providing the hall sensor 5 with flux have angular deviations, these deviations may cause the rotor position detection accuracy and precision to be degraded. In order to eliminate the deviation of the installation angle of the two magnets, it is common practice to magnetize both magnets simultaneously or to perform angle compensation and calibration by electronic techniques after magnetizing the magnets separately, which affects the operability of motor assembly and increases the process complexity. In addition, the additional addition of magnets and spacers on the rotor can lead to complexity in the motor assembly process.

The utility model discloses a brushless motor can solve above-mentioned problem well. Referring to fig. 2 in particular, fig. 2 is a schematic diagram illustrating a rotor structure and a rotor position detection method of a brushless motor according to an embodiment of the present invention. Wherein the rotor assembly comprises a rotor shaft 1, a rotor core 2 arranged on the rotor shaft 1 and a rotor permanent magnet 3.

As a specific embodiment, the rotor permanent magnet 3 is a magnetic ring disposed on the outer circumferential surface of the rotor core 2 and surrounding the rotor core 2. The rotor magnetic ring is generally circular, the outer diameter of the magnetic ring is 10-40 mm, and the inner diameter of the magnetic ring is 8-38 mm. The rotor magnetic ring is made of bonded neodymium iron boron, and the thickness of the magnetic ring is 1-4 mm. Fig. 3 shows an end view of the rotor permanent magnet 3. The rotor permanent magnet 3 can also be in other conventional arrangement modes besides a circular magnetic ring, such as a magnetic sheet type, a surface-mounted type, a buried type or a built-in type.

The hall sensor 5 is provided on the printed circuit board 4 facing the axial end face of the rotor permanent magnet 3. In order to supply the hall sensor 5 with magnetic flux for detecting the current position of the rotor, the axial dimension of the rotor permanent magnet 3 is set to be larger than the axial dimensions of the rotor core 2 and the stator core, and the excess portion a supplies the hall sensor 5 with magnetic flux for detecting the current position of the rotor, instead of the hall sensor magnet 6 of the related art. The Hall sensor magnet 6 is omitted, so that the procedures of unified magnetizing and adjusting the relative positions of the two magnets are omitted, and the process complexity is reduced. In addition, the magnetic flux consistency of the rotor permanent magnet 3 is superior to that of the two magnets, and therefore the rotor position detection accuracy is correspondingly improved. The mounting is also simplified since only one permanent magnet needs to be mounted.

As a specific embodiment, the dimension of the excess portion a is 2 to 8 mm. The axial end face of the excess part A is 1-2.5 mm away from the Hall sensor 5. Those skilled in the art know that the size of the excess portion a and the distance B of the excess portion a from the hall sensor 5, which satisfy the detection requirements, may be set according to the size of the brushless motor and the amount of magnetization of the rotor permanent magnet 3.

Referring to fig. 4, fig. 4 is a schematic diagram illustrating axial dimension relationships between a rotor core and a stator core of a brushless motor according to an embodiment of the present invention. As a specific embodiment, the axial dimension of the rotor core 2 is the same as the axial dimension C of the stator core 7.

Referring to fig. 5 and 6, two alternatives of a stator core of a brushless motor according to an embodiment of the present invention are shown. As shown in fig. 5, the outer shape of the stator core lamination may be circular, the outer diameter dimension E may be 20-60 mm, and the inner diameter dimension D may be 10-50 mm. As shown in fig. 6, the stator core lamination may have a hexagonal shape with a side dimension E 'of 20-60 mm and an inner diameter dimension D' of 10-50 mm.

As a specific implementation manner, the permanent magnet 3 is magnetized in a radial direction, and the leakage magnetic flux at a position 2 mm away from the axial end face of the permanent magnet 3 is not less than 200 gauss.

In a specific embodiment, the brushless motor is a three-phase brushless dc motor with an inner rotor structure.

Based on the same principle, the utility model also provides a brushless motor rotor position detection method, its realization principle is similar with above-mentioned brushless motor's realization principle, specifically can refer to the description of above-mentioned brushless motor part, and the same part is no longer repeated.

Referring to fig. 2 to 6, in the method for detecting the rotor position of the brushless motor of the present invention, the brushless motor includes a rotor assembly, a stator assembly and a hall sensor 5, the rotor assembly includes a rotor core 2 and a permanent magnet 3 disposed on the rotor core 2, the stator assembly includes a stator core 7 and a stator winding (not shown in the figure), and the method includes: the Hall sensor 5 is arranged facing to the axial end face of the rotor assembly; a part of the permanent magnet 3 is used to provide a magnetic flux to the hall sensor 5. In a specific embodiment, the hall sensor 5 is disposed on the printed circuit board 4, facing the axial end face of the rotor permanent magnet 3, and detects the rotor position by using the leakage magnetic flux of the axial end face of the rotor permanent magnet 3.

As a specific embodiment, the axial dimension of the rotor permanent magnet 3 is set to be larger than the axial dimensions of the rotor core 2 and the stator core, the excess portion a replaces the hall sensor magnet 6 of the prior art, and the hall sensor 5 is provided with magnetic flux for detecting the current position of the rotor.

In a specific embodiment, the dimension of the excess portion a is 2 to 8 mm.

As a specific embodiment, the axial dimension of the rotor core 2 is the same as the axial dimension C of the stator core 7.

In a specific embodiment, the rotor permanent magnet 3 is a circular magnetic ring, and may be disposed in other conventional manners besides the circular magnetic ring, such as a magnetic sheet type, a surface-mounted type, a buried type, or a built-in type. The rotor magnetic ring is made of bonded neodymium iron boron, and the thickness of the magnetic ring is 1-4 mm. The shape of the stator core lamination can be circular, the outer diameter E is 20-60 mm, and the inner diameter D is 10-50 mm. The outer shape of the stator core lamination can also be hexagonal, the dimension E 'of the opposite sides of the hexagon is 20-60 mm, and the dimension D' of the inner diameter is 10-50 mm.

The utility model discloses a brushless motor and brushless motor rotor position detection method uses rotor permanent magnet itself to provide the magnetic flow as hall sensor magnet to hall sensor, replaces two magnets of hall sensor magnet and rotor permanent magnet on the tradition, has saved and has unified the process of magnetizing and adjusting two magnet relative positions for hall sensor magnet and rotor permanent magnet, reduces the technology complexity, and rotor permanent magnet's magnetic flow uniformity improves greatly than two magnetic rings, therefore rotor position detection accuracy and the corresponding improvement of precision. In addition, installation is convenient because only one magnet needs to be installed.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited thereto. Various changes and modifications can be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention is to be determined by the appended claims.

Claims

1. The utility model provides a brushless motor, includes rotor subassembly, stator module and hall sensor, the rotor subassembly includes rotor core and sets up permanent magnet on the rotor core, stator module includes stator core and stator winding, hall sensor towards the axial terminal surface setting of rotor subassembly, its characterized in that, the axial dimension of permanent magnet is greater than stator core with rotor core's axial dimension surpasss the part and is used for to hall sensor provides the magnetic flux.

2. The brushless electric machine of claim 1, wherein the excess portion has a dimension of 2-8 millimeters.

3. The brushless electric machine of claim 2, wherein an axial dimension of the rotor core is the same as an axial dimension of the stator core.

4. A brushless electric machine according to any of claims 1-3, wherein the permanent magnets are circular magnetic rings.

5. The brushless motor according to any one of claims 1 to 3, wherein the permanent magnet is magnetized in a radial direction, and a leakage magnetic flux at a distance of 2 mm from an axial end face of the permanent magnet is not less than 200 gauss.

6. The brushless motor of any one of claims 1-3, wherein the brushless motor is a three-phase brushless DC motor of an inner rotor structure.

7. The brushless electric machine of any of claims 1-3, comprising a printed circuit board, the Hall sensors being disposed on the printed circuit board.

8. The brushless motor of any one of claims 1-3, wherein the axial end surface of the excess portion is at a distance of 1-2.5 mm from the Hall sensor.

9. The brushless motor of any one of claims 1-3, wherein the stator core has a circular outer shape with an outer diameter dimension of 20-60 mm and an inner diameter dimension of 10-50 mm.

10. The brushless electric machine of any of claims 1-3, wherein the stator core has an outer shape that is hexagonal with opposite sides having dimensions of 20-60 mm and an inner diameter having dimensions of 10-50 mm.