Direct-current brushless motor and electric appliance

Abstract

The utility model provides a direct-current brushless motor and an electric appliance. The direct-current brushless motor comprises a stator assembly and a rotor assembly, the upper end cover and the lower end cover clamp the stator assembly in the axial direction; the two ends of the control panel are fixedly connected with the upper end cover and the lower end cover respectively, the arrangement direction of the control panel is parallel to the axis direction of the stator assembly, gaps are formed between the control panel and the peripheral walls of the upper end cover and the lower end cover, and the control panel can control and adjust the rotating speed of the direct-current brushless motor. According to the direct-current brushless motor provided by the invention, a motor shell is omitted, the weight and the axial length of the whole motor are reduced, and heat of the stator assembly can be directly dissipated from the exposed part between the two end covers; the control panel and the motor are integrated, the control panel can be cooled through the end covers on the two sides, the rotating speed of the motor is adjusted and changed through the control panel, the motor is made to be suitable for different application scenes, the purposes of the motor are expanded, a frequency converter needed for adjusting the rotating speed is omitted, and the single motor can be suitable for different purposes and is wide in applicability.

Description

Technical Field

[0001] The present application belongs to the field of motor technology, and more specifically, to a brushless DC motor and an electrical appliance. Background Art

[0002] With the development of microelectronics technology and automatic control technology, brushless DC motors are being used more and more widely, for example in fans, range hoods and various household appliances. Due to the single function of the motor, in order to be suitable for high-speed, medium-speed and low-speed application scenarios, multiple models of motors are generally produced and manufactured, and a single motor cannot meet the needs of various application scenarios. If the speed needs to be adjusted, the motor needs to be equipped with a frequency converter, but the frequency converter is expensive. At the same time, the existing brushless DC motors are large in size and weight, and take up a lot of space. Utility Model Content

[0003] The purpose of the embodiments of the present application is to provide a brushless DC motor and an electrical appliance to solve the technical problems existing in the prior art that the motor has a single function and is large in size and weight.

[0004] To achieve the above purpose, the technical solution adopted in this application is: to provide a brushless DC motor, comprising:

[0005] A stator assembly and a rotor assembly rotatably disposed within the stator assembly;

[0006] An upper end cover and a lower end cover, wherein the upper end cover and the lower end cover clamp the stator assembly in an axial direction;

[0007] A control board, both ends of which are respectively connected and fixed to the upper end cover and the lower end cover, the arrangement direction of the control board is parallel to the axial direction of the stator assembly, and there is a gap between the control board and the outer peripheral walls of the upper end cover and the lower end cover, and the control board can control and adjust the rotation speed of the DC brushless motor.

[0008] In one embodiment, the upper end cover is provided with a first extension portion extending radially outward, the lower end cover is provided with a second extension portion extending radially outward, and both ends of the control board are respectively fixed to the first extension portion and the second extension portion by screws.

[0009] In one embodiment, both the first extension portion and the second extension portion are L-shaped structures, and a plurality of heat sinks are provided on a side of the second extension portion facing away from the control board.

[0010] In one embodiment, the end surfaces of the upper end cover and the lower end cover are respectively provided with a plurality of first ventilation holes spaced circumferentially, and / or the side walls of the upper end cover and the lower end cover are respectively provided with a plurality of second ventilation holes circumferentially.

[0011] In one embodiment, the rotor assembly includes a rotor chip and a plurality of magnetic tiles arranged on or near the outer circumferential surface of the rotor chip in a circumferential direction, and a rotating shaft coaxially fixed to the rotor chip; the stator assembly includes a stator chip and a winding, the stator chip is provided with stator slots and stator teeth in an annular ring, the winding is wound on the stator teeth, and each of the stator teeth forms a accommodating space for accommodating the rotor chip.

[0012] In one embodiment, the number of the stator slots is 12 and the number of the magnetic tiles is 14.

[0013] In one embodiment, the number of the stator slots is set to 9, 15 or 18, and the number of the magnetic tiles is set to 8, 10, 12, 16 or 20.

[0014] In one embodiment, the outer diameter of the stator core piece is in the range of 66-140 mm; the outer diameter of the rotor core piece is in the range of 34.8-78.8 mm.

[0015] In one embodiment, the brushless DC motor further includes a magnetic encoder, which includes a magnetic encoder circuit board and a permanent magnet. The magnetic encoder circuit board is fixed to a side of the lower end cover away from the rotor assembly. A linear Hall sensor is provided on a side of the magnetic encoder circuit board facing the rotor assembly. The permanent magnet is coaxially fixed to the rotating shaft through a collar. The magnetic encoder circuit board is communicatively connected to the control board, and the magnetic encoder circuit board sends a position signal of the rotor assembly to the control board.

[0016] An electrical appliance comprises the above-mentioned brushless DC motor.

[0017] The beneficial effects of the brushless DC motor provided by the present application are as follows: compared with the prior art, the brushless DC motor of the present application, the upper end cover and the lower end cover clamp and support the stator assembly, eliminating the motor housing, reducing the weight and axial length of the whole machine, and most of the peripheral side of the stator assembly is exposed, and heat can be directly dissipated from the exposed part between the two end covers; the control board is connected and fixed to one side of the upper end cover and the lower end cover, on the one hand, the control board and the motor are integrated into one, and the control board can be cooled through the end covers on both sides, and on the other hand, the motor speed is changed by adjusting the control board, so that the motor is suitable for different application scenarios, expanding its use, eliminating the frequency converter required for adjusting the speed, and having a low cost. A single motor can be suitable for different uses, and has a wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 A three-dimensional diagram of a brushless DC motor provided in an embodiment of the present application;

[0020] Figure 2 for Figure 1 A side view of the brushless DC motor shown;

[0021] Figure 3 for Figure 1 A partial structural schematic diagram of a brushless DC motor is shown;

[0022] Figure 4 for Figure 3 Another angle schematic diagram of the structure of the brushless DC motor shown;

[0023] Figure 5 for Figure 1 A partial exploded view of the brushless DC motor shown;

[0024] Figure 6 for Figure 3 A top view of a partial structure of a brushless DC motor is shown;

[0025] Figure 7 For along Figure 6 Sectional view along line AA;

[0026] Figure 8 for Figure 7 The enlarged schematic diagram of the middle part B;

[0027] Fig. 9 for Figure 8 Schematic diagram of the structure of the permanent magnet;

[0028] Fig.10 It is a schematic diagram of the assembly structure of the stator assembly and the rotor assembly;

[0029] Fig.11 It is a schematic diagram of the partial assembly structure of the stator assembly and the rotor assembly;

[0030] Fig.12 for Fig.11 A top view of the stator chip;

[0031] Fig.13 for Fig.11 Top view of the middle rotor chip;

[0032] Fig.14 for Fig.13 A magnified top view of the middle magnetic tile;

[0033] Fig.15 for Fig.14 A three-dimensional image of the middle magnetic tile;

[0034] Fig.16 for Fig.14 Side view of the center magnetic tile.

[0035] Among them, the reference numerals in the figure are:

[0036] 10- stator assembly; 20- rotor assembly; 30- upper end cover; 40- lower end cover; 50- control board; 60- magnetic encoder; 11- stator chip; 12- winding; 121- lead wire; 110- stator slot; 111- stator tooth; 13- skeleton; 131- upper skeleton; 132- lower skeleton; 133- winding tooth; 21- rotor chip; 22- magnetic tile; 23- rotating shaft; 210- slot body; 24- feeding plate; 31- first extension; 32- screw; 33- bearing; 41- second extension; 410- heat sink; 42- first ventilation hole; 43- second ventilation hole; 44- through hole; 45- connecting column; 61- magnetic encoder circuit board; 62- permanent magnet; 63- linear Hall sensor; 64- magnetic encoder circuit board lead wire; 65- collar; 66- screw. DETAILED DESCRIPTION

[0037] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0038] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0039] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0041] Please also read Figures 1 to 5 , the brushless DC motor provided by the embodiment of the present application is now described. The brushless DC motor includes a stator assembly 10, a rotor assembly 20, an upper end cover 30, a lower end cover 40 and a control board 50. The rotor assembly 20 is rotatably arranged in the stator assembly 10, the stator assembly 10 has a winding 12, the control board 50 and the winding 12 are electrically connected through a lead 121, and a rectifier bridge for converting AC into DC is provided on the control board 50. The upper end cover 30 and the lower end cover 40 clamp the stator assembly 10 in the axial direction, and the upper end cover 30 and the lower end cover 40 clamp and support the stator assembly 10, eliminating the iron core shell of the traditional motor, reducing metal materials, saving costs, and reducing the weight and axial length of the whole machine. There is a gap between the open end of the upper end cover 30 and the open end of the lower end cover 40, and at least a part of the stator chip 11 of the stator assembly 10 is exposed, so that heat can be directly dissipated from the exposed part between the two end covers.

[0042] The two ends of the control board 50 are respectively connected and fixed to the upper end cover 30 and the lower end cover 40, and can be fixed to the two end covers by screws, clamps or connectors. In this embodiment, the upper end cover 30 is connected and fixed to the lower end cover 40 by a plurality of screws 32, such as Figures 3 to 5 As shown, the upper end cover 30 and the lower end cover 40 are respectively provided with connection holes at positions equally divided on the circumference of the outer circumference thereof, and the upper end cover 30 and the lower end cover 40 are connected and fixed by three screws 32, and the outer circumferential surface of the stator chip 11 of the stator assembly 10 is provided with an escape groove for escaping the screws 32. The upper end cover 30 and the lower end cover 40 can be made of aluminum or aluminum alloy, which has good thermal conductivity, can meet the heat dissipation requirements of the control board 50, and are light in weight, cost-saving, compact in structure, and small in space.

[0043] The layout direction of the control board 50 is parallel to the axial direction of the stator assembly 10, and there is a gap between the control board 50 and the outer peripheral wall of the upper end cover 30, and between the control board 50 and the outer peripheral wall of the lower end cover 40. The control board 50 can control and adjust the speed of the DC brushless motor. For different application scenarios, the corresponding parameters can be set through the control board 50 to change the speed of the motor. The control board 50 can control the motor speed to switch between 40-8000rpm or higher speeds at will, expand its use, and eliminate the need for a frequency converter for adjusting the speed. A single motor can be suitable for different uses, with wide applicability and good versatility, which can enhance the competitiveness of the product.

[0044] When the brushless DC motor provided in this embodiment is applied to a food processor, the motor speed can be adjusted to 40 rpm through the control panel 50 to squeeze juice, 500 rpm for slicing, 400 rpm for silent dough kneading, 800 rpm for cutting vegetables, 1600 rpm for dough kneading, and higher than 1600 rpm for mincing meat. A single motor can be adapted to the processing requirements of different foods, making it a multifunctional food processor. When a higher motor speed is adjusted through the control panel 50, it can be applied to other electrical appliances, such as the power part of washing machines, oil pumps, water pumps, air conditioner outdoor units, range hoods, large fans, stirring appliances, etc., greatly increasing the scope of application.

[0045] Compared with the prior art, the brushless DC motor provided in the present application has an upper end cover 30 and a lower end cover 40 that clamp and support the stator assembly 10, eliminating the motor housing, reducing the weight and axial length of the whole machine, and most of the outer peripheral side of the stator assembly 10 is exposed, and heat can be directly dissipated from the exposed portion between the two end covers; the control board 50 is connected and fixed to one side of the upper end cover 30 and the lower end cover 40, on the one hand, the control board 50 and the motor are integrated into one, and the control board 50 can be dissipated through the end covers on both sides. On the other hand, the motor speed can be adjusted by the control board 50 to make the motor suitable for different application scenarios, expand its use, eliminate the frequency converter required for adjusting the speed, have a low cost, and a single motor can be suitable for different uses, with wide applicability.

[0046] See also Figures 1 to 3 , the upper end cover 30 is provided with a first extension portion 31 extending radially outward, and the lower end cover 40 is provided with a second extension portion 41 extending radially outward, the first extension portion 31 is integrally formed with the upper end cover 30, and the second extension portion 41 is integrally formed with the lower end cover 40. Specifically, the first extension portion 31 and the second extension portion 41 are both L-shaped plates, and the two ends of the control board 50 are respectively fixed to the axially extending plates of the first extension portion 31 and the second extension portion 41 by screws. Connecting columns are respectively provided near each corner of the control board 50, and screws are passed through the control board 50 and the connecting columns to connect with the first extension portion 31 and the second extension portion 41, thereby connecting and fixing the control board 50, so that the control board 50 is integrated with the motor. Figure 3 , Figure 4 and Figure 6 As shown, the first extension portion 31 extends radially outward from the outer circumferential wall of the upper end cover 30, and the width of the first extension portion 31 can be set to be less than or equal to the diameter of the upper end cover 30. The second extension portion 41 extends radially outward along the end surface of the lower end cover 40, and the width of the second extension portion 41 can be set to be greater than or equal to the diameter of the lower end cover 40.

[0047] See also Figure 1 , Figure 3 and Figure 4 A plurality of heat sinks 410 are provided on the side of the second extension portion 41 away from the control board 50, that is, a heat sink 410 is provided on a plate in the second extension portion 41 parallel to the axis direction of the motor, and the heat sink 410 and the control board 50 are located on opposite sides of the plate. In this way, the heat sink 410 provided on the second extension portion 41 forms a radiator, further improving the heat dissipation performance, cleverly using the end cover to dissipate heat for the control board 50, eliminating the aluminum alloy heat sink dedicated to the traditional motor, saving costs, and at the same time reducing the axial length and occupying less space.

[0048] See also Figure 1 and Figure 3 , the end faces of the upper end cover 30 and the lower end cover 40 are respectively provided with a plurality of first ventilation holes 42 spaced circumferentially, and / or, the side walls of the upper end cover 30 and the lower end cover 40 are respectively provided with a plurality of second ventilation holes 43 circumferentially. In this embodiment, the end faces of the upper end cover 30 and the lower end cover 40 are respectively provided with six first ventilation holes 42, and the first ventilation holes 42 are roughly fan-shaped. The lead wire 121 connected to the winding 12 in the stator assembly 10 passes through one of the first ventilation holes 42 and is electrically connected to the control board 50. The side walls of the upper end cover 30 and the lower end cover 40 are respectively provided with six second ventilation holes 43, and the second ventilation holes 43 are roughly rectangular. In this way, the end faces and side faces of the two end covers can be ventilated and heat dissipated through these holes, which further improves the heat dissipation performance of the motor and can meet the heat dissipation requirements.

[0049] See also Figure 5 , Figure 7 and Figure 8 The rotor assembly 20 includes a rotor core 21, a plurality of magnetic tiles 22 and a rotating shaft 23. The plurality of magnetic tiles 22 are arranged on the outer peripheral surface of the rotor core 21 or near the outer peripheral surface along the circumferential direction, and the pairs of magnetic tiles 22 are arranged circumferentially at intervals. In this embodiment, the magnetic tiles 22 are rectangular magnetic blocks, and the magnetic tiles 22 are arranged at a position close to the outer peripheral surface of the rotor core 21, that is, a groove adapted to the magnetic tiles 22 is arranged at a position close to the outer peripheral edge of the rotor core 21, and the magnetic tiles 22 are fixed in the groove. The rotating shaft 23 is coaxially fixed to the rotor core 21, and the upper end cover 30 and the lower end cover 40 are respectively provided with a bearing 33 chamber, and the bearing 33 is fixed in the bearing 33 chamber. The two ends of the rotating shaft 23 are respectively fixed to the bearings 33 on both sides, and one end of the rotating shaft 23 extends from the rotor core 21 and has a gap with the lower end cover 40, and the other end of the rotating shaft 23 extends from the center of the upper end cover 30.

[0050] See also Figure 5 , Fig.11 , Fig.12The stator assembly 10 includes a stator core 11 and a winding 12. Both the rotor core 21 and the stator core 11 can be made of laminated silicon steel sheets. The stator core 11 is provided with stator slots 110 and stator teeth 111. The winding 12 is wound on the stator teeth 111. Each stator tooth 111 forms a storage space for the rotor core 21. The outer surface of the stator core 11 is provided with a clearance groove for escaping the screws 32, so that the whole machine is more compact after assembly; since the motor housing is omitted, most or all of the outer surface of the stator core 11 is exposed, and the heat generated by the stator core 11 can be quickly dissipated from the exposed part.

[0051] See also Figure 5 , Figure 7 , Fig.10 and Fig.11 The axial end surface of the stator chip 11 is provided with a skeleton 13 made of insulating material. The skeleton 13 includes an upper skeleton 131 and a lower skeleton 132 arranged opposite to each other. The winding 12 is wound on the skeleton 13. The upper end cover 30 is sleeved with the upper skeleton 131, and the lower end cover 40 is sleeved with the lower skeleton 132. The upper end cover 30 and the lower end cover 40 are both against the corresponding end surface of the stator chip 11, and the outer peripheral surface of the stator chip 11 is completely exposed. A plurality of winding teeth 133 are evenly spaced along the circumferential direction on the inner side wall of the skeleton 13. The plurality of winding teeth 133 are sleeved on the outside of each stator tooth 111 of the stator chip 11 one by one. During installation, the upper skeleton 131 and the lower skeleton 132 are sleeved on the stator chip 11, and then the winding 12 is formed by winding on the winding teeth 133. After the winding 12 is completed, it is electrically connected to the control board through the lead 121.

[0052] See also Figures 11 to 13 , the outer diameter D of the stator core 11 1 The range is 66-140mm, and the inner diameter D of the stator core 11 2 The range of the outer diameter D of the rotor core piece 21 is 36-80 mm. 3 The range is 34.8-78.8mm. The DC brushless motor can reduce the overall volume by about 45% while outputting the same torque. It can be understood that the outer diameters of the stator chip 11 and the rotor chip 21 can be increased or decreased in the same proportion.

[0053] The rotor core 21 is provided with a plurality of slots 210 arranged at intervals along the circumferential direction. The number and position of the slots 210 can be set one-to-one with the number and position of each magnetic tile 22. The shape of the slots 210 is approximately fan-shaped. The rotor core 21 is provided with a plurality of slots 210, which can reduce the weight of the rotor core 21, thereby reducing the overall moment of inertia of the rotor core 21, and is conducive to improving the starting and response speed of the motor. The diameter D of the circumscribed circle of each slot 210 is 4 Than D 3The difference between the two can be set to 2-20 mm. The diameter D of the inscribed circle of each slot body 210 is 5 Than D 4 Since the motor housing is omitted, the extended parts of the end covers on both sides are fully utilized for heat dissipation, and the rotor chip 21 is hollowed out to form a plurality of slots 210, the overall weight of the motor can be reduced by 45%.

[0054] The number of stator slots 110 on the stator core 11 can be set to 9, 12, 15 or 18, and the number of magnetic tiles 22 on the rotor core 21 can be set to 8, 10, 12, 14, 16 or 20.

[0055] See also Figures 12 to 16 In this embodiment, there are 12 stator slots 110 and 14 magnetic tiles 22, that is, the motor is a 12-slot 14-pole DC brushless motor. Under the condition of outputting the same torque, the volume is smaller than that of a traditional motor. The width L of the magnetic tile 22 is 2 The range is 8-16 mm, and the slot width L of the stator slot 110 is 3 The range is 2-6mm, the width L of the stator tooth 111 at the root 1 In this embodiment, the outer diameter D of the stator core 11 is 4-12 mm. 1 125mm, inner diameter D 2 The outer diameter D of the rotor core 21 is 76 mm. 3 The width L of the magnetic tile 22 is 74.4 mm. 2 is 13 mm, and the length L of the magnetic tile 22 is 4 The thickness H of the magnetic tile 22 is 35 mm, and the thickness H of the magnetic tile 22 is 2.6 mm. Along the thickness direction of the magnetic tile 22, one side is the N pole and the other side is the S pole. The corners of the two adjacent faces of the magnetic tile 22 and the corners of the three adjacent faces are all smooth transitions. The radius R of the corners of the two adjacent faces can be set to 0.5 mm. The slot width L of the stator slot 110 is 3 The width L of the root of the stator tooth 111 is 5 mm. 1 The axial length of the center of the two end covers is about 60mm, while the axial length of the traditional motor is more than 100mm. Under the condition of outputting the same torque, the volume and weight are reduced by about 45%. At a low speed such as 40rpm, it can output 80 to 100kg·m. Low speed can output high torque, which can realize the function of mixing and processing food quietly.

[0056] It is understandable that the number of stator slots 110 and magnetic tiles 22 may also be other combinations, such as 12 slots with 10 poles or 16 poles, and 15 slots with 14 poles, 16 poles or 20 poles.

[0057] See also Figure 1 , Figure 5 , Figure 8 and Fig. 9 , the brushless DC motor also includes a magnetic encoder 60. The magnetic encoder 60 includes a magnetic encoder circuit board 61 and a permanent magnet 62. A linear Hall sensor 63 is provided on the magnetic encoder circuit board 61, and the linear Hall sensor 63 is located on the side of the magnetic encoder circuit board 61 facing the rotor assembly 20. The permanent magnet 62 of the magnetic encoder 60 is coaxially fixed to one end of the rotating shaft 23 through a sleeve ring 65. The permanent magnet 62 is in a flat cylindrical shape, and its N pole and S pole are arranged oppositely and are both semicircular. The diameter of the permanent magnet 62 is slightly smaller than the diameter of the corresponding end of the rotating shaft 23, and the end face of the permanent magnet 62 is parallel to the end face of the rotating shaft 23. The sleeve ring 65 can be, but is not limited to, a copper sleeve ring, and can also be made of other non-magnetic materials, such as an aluminum alloy sleeve ring. The top surface of the sleeve ring 65 has a fixing groove adapted to accommodate and fix the permanent magnet 62. There is a gap between the permanent magnet 62 and the linear Hall sensor 63, and there is a gap between the permanent magnet 62 and the rotating shaft 23. The magnetic encoder circuit board 61 is connected to the control board 50 through the magnetic encoder circuit board lead 64. The magnetic encoder 60 converts the position signal of the rotor assembly 20 into an electrical signal and transmits it to the control board 50. The control board 50 controls the winding 12 on the stator assembly 10. The lower end cover 40 is provided with a through hole 44 for the collar 65 to pass through at the position corresponding to the rotating shaft 23. One end of the collar 65 extends into the through hole 44, and the other end of the collar 65 extends out of the lower end cover 40. Three connecting posts 45 are provided in the circumferential direction of the outer surface of the lower end cover 40 at the periphery of the through hole 44. The magnetic encoder circuit board 61 is in the shape of a large cut circle as a whole, and one side of it is a straight edge. Two connecting posts 45 are respectively located near the two ends of the straight edge. The magnetic encoder circuit board 61 is connected to the connecting posts 45 by screws 66, thereby fixing the magnetic encoder circuit board 61 on the lower end cover 40. The magnetic encoder 60 is easy to install. One end of the magnetic encoder circuit board lead 64 is provided with a terminal for connecting to the control board 50.

[0058] Compared with the switch Hall sensor, the linear Hall sensor 63 can output different voltages according to the change of magnetic field strength. The output voltage is continuous and linearly related to the magnetic field strength, with high accuracy and resolution. The existing motor uses a switch Hall sensor, which outputs a digital signal with only two output states. When the motor rotates at a low speed, it is difficult to effectively detect due to the small rotation angle. Its accuracy and resolution are relatively low, which leads to unstable output torque. For example, when the motor speed is 40rpm, a switch Hall sensor is used, which can only detect the conversion of its magnetic poles, which is difficult to detect effectively, easy to jam and jitter, and the torque output is unstable. The linear Hall sensor 63 can realize precise control of the motor, and can effectively detect when the motor rotates at high and low speeds, with smooth rotation and stable torque output.

[0059] See also Figure 7 , Figure 8 , Fig.10 The axial length of the rotor chip 21 is set to be equal to or close to the axial length of the stator chip 11, and the end face of the rotor chip 21 is flush or substantially flush with the corresponding end face of the stator chip 11. Feeding plates 24 are fixed to the two axial end faces of the rotor chip 21, respectively, and the outer diameter of the feeding plate 24 is equal to the outer diameter of the rotor chip 21. The feeding plate 24 is hollowed out to form a grid-like structure, which is lighter as a whole. The feeding plates 24 are arranged at both axial ends of the rotor chip 21 to reduce the shaking of the rotor assembly 20 when it rotates, avoid shaking, reduce the loss caused by imbalance when the rotor assembly 20 rotates, and improve the efficiency of the motor.

[0060] The electrical appliance of the embodiment of the present application includes the brushless DC motor described in the above embodiment. The electrical appliance may be, but is not limited to, a food processor, a washing machine, an oil pump, a water pump, an air conditioner outdoor unit, a range hood, a large fan, or a blender or an ice-smoothie crusher. When the brushless DC motor is applied to a food processor, since its speed is adjustable and the adjustment range is large, the motor can be used for juicing, slicing, kneading noodles silently, chopping vegetables or mincing meat, thus forming a multifunctional food processor. One motor can be suitable for different application scenarios, and there is no need to purchase multiple different motors with low, medium and high speeds, thus broadening the scope of application.

[0061] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A brushless DC motor, characterized in that: include: A stator assembly and a rotor assembly rotatably disposed within the stator assembly; An upper end cover and a lower end cover, wherein the upper end cover and the lower end cover clamp the stator assembly in an axial direction; A control board, both ends of which are respectively connected and fixed to the upper end cover and the lower end cover, the arrangement direction of the control board is parallel to the axial direction of the stator assembly, and there is a gap between the control board and the outer peripheral walls of the upper end cover and the lower end cover, and the control board can control and adjust the rotation speed of the DC brushless motor.

2. The brushless DC motor according to claim 1, characterized in that: The upper end cover is provided with a first extension portion extending radially outward, the lower end cover is provided with a second extension portion extending radially outward, and two ends of the control board are respectively fixed to the first extension portion and the second extension portion by screws.

3. The brushless DC motor according to claim 2, characterized in that: The first extension portion and the second extension portion are both L-shaped structures, and a plurality of heat sinks are provided on a side of the second extension portion away from the control board.

4. The brushless DC motor according to claim 1, wherein: The end surfaces of the upper end cover and the lower end cover are respectively provided with a plurality of first ventilation holes spaced circumferentially, and / or the side walls of the upper end cover and the lower end cover are respectively provided with a plurality of second ventilation holes circumferentially.

5. The brushless DC motor according to claim 1, characterized in that: The rotor assembly includes a rotor chip and a plurality of magnetic tiles arranged on or near the outer circumferential surface of the rotor chip in a circumferential direction, and a rotating shaft coaxially fixed to the rotor chip; the stator assembly includes a stator chip and a winding, the stator chip is provided with stator slots and stator teeth in an annular ring, the winding is wound on the stator teeth, and each of the stator teeth forms a accommodating space for accommodating the rotor chip.

6. The brushless DC motor according to claim 5, characterized in that: The number of stator slots is 12, and the number of magnetic tiles is 14.

7. The brushless DC motor according to claim 5, characterized in that: The number of the stator slots is set to 9, 15 or 18, and the number of the magnetic tiles is set to 8, 10, 12, 16 or 20.

8. The brushless DC motor according to claim 5, characterized in that: The outer diameter of the stator core is in the range of 66-140 mm; the outer diameter of the rotor core is in the range of 34.8-78.8 mm.

9. The brushless DC motor according to claim 5, characterized in that: The brushless DC motor also includes a magnetic encoder, which includes a magnetic encoder circuit board and a permanent magnet. The magnetic encoder circuit board is fixed to a side of the lower end cover away from the rotor assembly. A linear Hall sensor is provided on a side of the magnetic encoder circuit board facing the rotor assembly. The permanent magnet is coaxially fixed to the rotating shaft through a collar. The magnetic encoder circuit board is communicatively connected to the control board, and the magnetic encoder circuit board sends a position signal of the rotor assembly to the control board.

10. An electrical appliance, characterized in that: A brushless DC motor comprising any one of claims 1 to 9.

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