Brushless direct current motor

Abstract

The embodiment of the utility model discloses a brushless direct current motor, which relates to the technical field of motors and comprises a casing, a circuit board, a first cover body and a second cover body. The machine shell is provided with a first spigot, a second spigot and a third spigot, and the first spigot and the second spigot are located on the same side of the machine shell. The first cover body is connected with the first spigot, the circuit board is connected with the second spigot, and the second cover body is connected with the third spigot; the machine shell is made of soft magnetic composite materials and is formed at a time through die casting of a metal die. The brushless direct current motor is free of a stator iron core, the casing structure has a protection function of the casing and a magnetic function of the iron core, and the casing can be formed at one time through die casting, so that the casing processing precision is improved, the motor power is improved, and the qualified rate of finished products is further improved.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, in particular to a brushless DC motor. Background Art

[0002] The hollow cup winding motor can reduce the weight of the motor, simplify the structure, make the motor smaller, and increase the power density because the winding does not use an iron core. At the same time, it can save the eddy current and hysteresis loss caused by the iron core, improve the motor efficiency, reduce the winding inductance, and make the mechanical characteristic curve tend to be linear. The electromagnetic time constant is smaller than that of traditional motors with the same power. Without an iron core, there is no cogging torque, the speed fluctuation is small, the motor runs smoothly, and the control response is fast and accurate. Therefore, it is increasingly used in high-tech fields such as drones, aerospace, high-precision instruments, autonomous flight control systems, and especially humanoid robots.

[0003] However, the hollow cup winding motor also has disadvantages. Its structural strength is weak, the power cannot be too large, the manufacturing process is relatively complex, and the production cost is high. The assembly of the motor housing and the front / rear end cover should meet the rotor runout tolerance design value and be easy to assemble. The hollow cup winding should be able to be smoothly installed into the housing and ensure a uniform gap between the rotor and the winding. The PCBA board should be easy to install and fix. There are usually stoppers for installing the front / rear end covers at both ends of the housing, and there are PCBA board installation and fixing positions inside the housing. If it is processed by machining or stamping or a combination of the two, it is often difficult to make molds and fixtures due to the small parts, and the precision is difficult to guarantee due to the large number of production processes, which affects the production efficiency of the motor and the qualified rate of the finished product. Utility Model Content

[0004] The technical problem to be solved by the embodiments of the utility model is that the machining precision of the motor housing is low, resulting in low motor power and low qualified rate of finished products.

[0005] In order to solve the above problems, the embodiment of the utility model discloses a brushless DC motor. The brushless DC motor has no stator core, and the housing structure includes the protection function of the housing and the magnetic function of the core. The housing can be formed by die casting in one step to improve the processing accuracy of the housing, increase the motor power, and thus improve the qualified rate of finished products.

[0006] The utility model provides a brushless DC motor, which includes a casing, a circuit board, a stator assembly, a first cover body and a second cover body; the casing is provided with a first stopper, a second stopper and a third stopper, and the first stopper and the second stopper are on the same side of the casing; the stator assembly is arranged in the casing, between the second stopper and the third stopper; the first cover body is connected to the first stopper, the circuit board is connected to the second stopper, and the second cover body is connected to the third stopper; the casing is formed in one step by die-casting with a metal mold.

[0007] A further technical solution is that the housing is further provided with a positioning groove, the circuit board is provided with a positioning portion that cooperates with the positioning groove, and the positioning groove is on the second stop.

[0008] A further technical solution is that it also includes a mover assembly, and the stator assembly is arranged around the mover assembly.

[0009] Its further technical solution is that it also includes a first bearing and a second bearing, the first bearing is arranged on the first cover body, and the second bearing is arranged on the second cover body; the mover assembly includes a shaft body and a magnetic ring, the magnetic ring is arranged around the shaft body, and the shaft body is respectively connected to the first bearing and the second bearing.

[0010] A further technical solution is that it also includes a limit ring, which is sleeved on the shaft.

[0011] A further technical solution is that it also includes an elastic member, which is connected to the limiting ring and the first cover body respectively, and is between the limiting ring and the first cover body.

[0012] A further technical solution is that the first cover body is also provided with a wire hole.

[0013] A further technical solution is that it also includes a wire sleeve, which can pass through the wire hole.

[0014] A further technical solution is that the housing is further provided with a void avoidance groove, the void avoidance groove is on the second stop, and the wire sleeve is connected to the void avoidance groove.

[0015] A further technical solution is that the stator assembly is bonded to the inner wall of the casing.

[0016] Compared with the prior art, the technical effects achieved by the embodiments of the present invention include:

[0017] The first stop, the second stop and the third stop are formed by die-casting the casing in one time. The die-casting process has high production efficiency and the inner wall of the casing has high precision. The first stop fits tightly with the first cover body, the second stop fits tightly with the circuit board, and the third stop fits tightly with the third cover body. A stator assembly is provided between the second stop and the third stop. The casing is formed by complex parts in one time, and the insulating layer between the stator assembly and the casing can be omitted, thereby further saving wire materials and simplifying the process. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0019] Figure 1 A schematic diagram of the structure of a brushless DC motor provided in an embodiment of the utility model;

[0020] Figure 2 A schematic diagram of another brushless DC motor structure provided by an embodiment of the utility model;

[0021] Figure 3 A cross-sectional view of a brushless DC motor structure provided by an embodiment of the utility model;

[0022] Figure 4 A schematic diagram of another brushless DC motor structure provided by an embodiment of the utility model;

[0023] Figure 5 A schematic diagram of another brushless DC motor structure provided by an embodiment of the utility model;

[0024] Figure 6 A schematic diagram of another brushless DC motor structure provided by an embodiment of the utility model;

[0025] Figure 7 A cross-sectional view of another brushless DC motor structure provided by an embodiment of the utility model;

[0026] Figure 8 A schematic diagram of a casing structure provided by an embodiment of the utility model;

[0027] Fig. 9 A schematic diagram of another casing structure provided for an embodiment of the utility model.

[0028] Reference numerals

[0029] Casing 1, circuit board 2, stator assembly 3, first cover body 4, second cover body 5, first stopper 11, second stopper 12, third stopper 13, positioning groove 14, positioning part 21, mover assembly 6, first bearing 71, second bearing 72, shaft 61, magnetic ring 62, limit ring 8, elastic member 9, wire hole 41, wire sleeve 10, and air avoidance groove 15. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments. Similar component numbers in the drawings represent similar components. Obviously, the embodiments to be described below are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0031] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0032] It should also be understood that the terms used in this utility model embodiment specification are only for the purpose of describing specific embodiments and are not intended to limit the utility model embodiments. As used in the utility model embodiment specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0033] See also Figure 1-9 , an embodiment of the utility model provides a brushless DC motor. The brushless DC motor includes a housing 1, a circuit board 2, a stator assembly 3, a first cover body 4 and a second cover body 5; the housing 1 is provided with a first stopper 11, a second stopper 12 and a third stopper 13, and the first stopper 11 and the second stopper 12 are on the same side of the housing 1; the stator assembly 3 is arranged in the housing 1, between the second stopper 12 and the third stopper 13; the first cover body 4 is connected to the first stopper 11, the circuit board 2 is connected to the second stopper 12, and the second cover body 5 is connected to the third stopper 13; the housing 1 is made of a soft magnetic composite material, and the housing 1 is formed in one step by die-casting with a metal mold. The specific introduction of each component is as follows:

[0034] In this embodiment, the housing of the brushless DC motor is formed by covering the housing 1, the first cover body 4 and the second cover body 5. The housing 1 is hollow and cylindrical. The first cover body 4 covers the first opening of the housing 1, and the second cover body 5 covers the second opening of the housing 1. The housing 1 is formed by a one-time molding to obtain a first stopper 11, a second stopper 12 and a third stopper 13. The first stopper 11, the second stopper 12 and the third stopper 13 are respectively parts of different inner diameters of the inner wall of the housing 1. The first stopper 11 and the second stopper 12 are at the first opening of the housing 1. The diameter of the first stopper 11 is greater than the diameter of the second stopper 12. The first stopper 11 fits the first opening, and the second stopper 12 fits the first stopper 11. A stepped inner wall channel is formed on one side of the housing 1 through the first stopper 11 and the second stopper 12. The third stopper 13 is at the second opening of the housing 1, and a stepped inner wall channel is formed on the other side of the housing 1 through the third stopper 13. The circuit board 2 includes a PCBA board. In one embodiment, the circuit board 2 is annularly attached to the second stop 12 of the housing 1. The stator assembly 3 includes a winding (also called enameled wire), which is a coil arranged and connected according to a certain rule. In one embodiment, the stator assembly 3 is arranged on the inner wall of the housing 1.

[0035] Soft magnetic composite materials, including a new generation of soft magnetic composite materials (Soft Magnetic Composite, SMC), can achieve good results by changing the manufacturing process of the casing 1. SMC material is a new type of soft magnetic material that uses powder metallurgy technology to form workpieces of various required shapes after the surface of high-purity iron powder particles is coated with an insulating medium. The casing 1 made of soft magnetic composite materials has the advantages of high saturation magnetic induction, high Curie temperature, extremely low high-frequency eddy current loss, and a wider operating temperature range. The casing structure includes the protection function of the shell and the magnetic function of the iron core.

[0036] The technical effects that the brushless DC motor can achieve are as follows:

[0037] The first stop 11, the second stop 12 and the third stop 13 are obtained by die-casting the housing 1 in one step. The die-casting process has high production efficiency and the inner wall of the housing 1 has high precision. The first stop 11 fits tightly to the first cover 4, the second stop 12 fits tightly to the circuit board 2, and the third stop 13 fits tightly to the third cover. A stator assembly 3 is provided between the second stop 12 and the third stop 13. The housing 1 is formed by a complex part in one step, and the insulating layer between the stator assembly 3 and the housing 1 can be omitted, further saving wire and simplifying the process. The motor has no iron core, and there is no cogging torque. The motor saves the eddy current and hysteresis losses caused by the iron core. The housing includes the protection function of the shell and the magnetic function of the iron core, which can improve the power of the motor.

[0038] Continue to see Figure 1-9In this embodiment, the housing 1 is further provided with a positioning groove 14 , and the circuit board 2 is provided with a positioning portion 21 that cooperates with the positioning groove 14 , and the positioning groove 14 is on the second stop 12 .

[0039] Specifically, the positioning groove 14 is a recessed portion at the second stop 12, and the positioning portion 21 is a protruding portion on the circuit board 2. The positioning portion 21 is fitted into the positioning groove 14. The positioning groove 14 and the positioning portion 21 are used to indicate the direction in which the circuit board 2 is installed in the housing 1, further increasing the fitting area between the circuit board 2 and the second stop 12, and preventing the circuit board 2 from loosening.

[0040] Furthermore, it also includes a mover assembly 6 , and the stator assembly 3 is arranged around the mover assembly 6 .

[0041] Specifically, the mover assembly 6 includes a permanent magnet, which cooperates with the stator assembly 3. After the stator assembly 3 is energized, the mover assembly 6 installed in the stator assembly 3 rotates.

[0042] Furthermore, it also includes a first bearing 71 and a second bearing 72, the first bearing 71 is arranged on the first cover body 4, and the second bearing 72 is arranged on the second cover body 5; the mover assembly 6 includes a shaft body 61 and a magnetic ring 62, the magnetic ring 62 is arranged around the shaft body 61, and the shaft body 61 is respectively connected to the first bearing 71 and the second bearing 72.

[0043] Specifically, the magnetic ring 62 is a permanent magnet. In one embodiment, the magnetic ring 62 is fixed on the shaft 61, and the stator assembly 3 surrounds the magnetic ring 62. The shaft 61 passes through the first bearing 71 of the first cover body 4, and the shaft 61 passes through the second bearing 72 of the second cover body 5. After the stator assembly 3 is energized, the magnetic ring 62 installed in the stator assembly 3 drives the shaft 61 to rotate, and the first bearing 71 and the second bearing 72 prevent the shaft 61 from jumping.

[0044] Furthermore, it also includes a limiting ring 8 , and the limiting ring 8 is sleeved on the shaft body 61 .

[0045] Specifically, there are usually multiple limiting rings 8 which are sleeved on the shaft body 61 . The limiting rings 8 of the shaft body 61 abut between the first cover body 4 and the second cover body 5 to prevent the shaft body 61 from moving in the vertical direction.

[0046] Furthermore, it also includes an elastic member 9, which is connected to the limiting ring 8 and the first cover body 4 respectively, and is between the limiting ring 8 and the first cover body 4.

[0047] Specifically, the elastic member 9 includes a spring, and the elastic member 9 is sleeved on the shaft body 61 and between the limiting ring 8 and the first cover body 4, so as to play a buffering role when the shaft body 61 moves in the vertical direction.

[0048] Furthermore, the first cover body 4 is also provided with a wire hole 41 .

[0049] Specifically, the circuit board 2 is provided with a connection terminal, and the first cover body 4 is provided with a wire hole 41 , and the wire can pass through the wire hole 41 to be connected with the connection terminal on the circuit board 2 .

[0050] Furthermore, it also includes a wire sleeve 10 , and the wire sleeve 10 can pass through the wire hole 41 .

[0051] Specifically, the wire sleeve 10 is made of a soft material, is sleeved on the wire, and is embedded in the wire hole 41 to prevent the wire from directly contacting the first cover 4 and to prevent the wire from bending and breaking at the wire hole 41 .

[0052] Furthermore, the housing 1 is further provided with a space-avoiding groove 15 , the space-avoiding groove 15 is on the second stop 12 , and the wire sleeve 10 is connected to the space-avoiding groove 15 .

[0053] Specifically, the housing 1 is formed by one-step die-casting with a metal mold, and is preset with an air avoidance groove 15. The air avoidance groove 15 is a recessed portion at the second stop 12, which is used to abut the wire sleeve 10 to increase the contact area between the housing 1 and the wire sleeve 10. The wire sleeve 10 is made of a soft material. Increasing the contact area between the housing 1 and the wire sleeve 10 can improve the sealing of the brushless DC motor.

[0054] Furthermore, the stator assembly 3 is bonded to the inner wall of the casing 1 .

[0055] The stator assembly 3 includes a hollow cup winding. In one embodiment, the stator assembly 3 can be directly bonded to the inner wall of the casing 1, and an insulating layer is omitted between the stator assembly 3 and the casing 1, thereby reducing costs.

[0056] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0057] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element 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 invention.

[0058] 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. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0059] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0060] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0061] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0062] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include these modifications and variations.

[0063] The above is a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the utility model, and these modifications or replacements should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A brushless DC motor, characterized in that: It includes a housing, a circuit board, a stator assembly, a first cover body and a second cover body; The housing is provided with a first stopper, a second stopper and a third stopper, wherein the first stopper and the second stopper are on the same side of the housing; The stator assembly is disposed in the housing between the second stop and the third stop; The first cover is connected to the first stopper, the circuit board is connected to the second stopper, and the second cover is connected to the third stopper; The housing is made of a soft magnetic composite material and is formed in one step by die-casting with a metal mold.

2. The brushless DC motor according to claim 1, characterized in that: The housing is also provided with a positioning groove, and the circuit board is provided with a positioning portion matched with the positioning groove, and the positioning groove is on the second stop.

3. The brushless DC motor according to claim 1, characterized in that: It also includes a mover assembly, and the stator assembly is arranged around the mover assembly.

4. The brushless DC motor according to claim 3, characterized in that: It also includes a first bearing and a second bearing, the first bearing is arranged on the first cover body, and the second bearing is arranged on the second cover body; the movable subassembly includes a shaft body and a magnetic ring, the magnetic ring is arranged around the shaft body, and the shaft body is connected to the first bearing and the second bearing respectively.

5. The brushless DC motor according to claim 4, characterized in that: It also includes a limiting ring, which is sleeved on the shaft body.

6. The brushless DC motor according to claim 5, characterized in that: It also includes an elastic member, which is respectively connected to the limiting ring and the first cover body, and is between the limiting ring and the first cover body.

7. The brushless DC motor according to claim 1, characterized in that: The first cover body is also provided with a wire hole.

8. The brushless DC motor according to claim 7, characterized in that: Also included is a wire sleeve, which can pass through the wire hole.

9. The brushless DC motor according to claim 8, characterized in that: The housing is also provided with a space-avoiding groove, the space-avoiding groove is on the second stop, and the wire sleeve is connected to the space-avoiding groove.

10. The brushless DC motor according to claim 1, characterized in that: The stator assembly is bonded to the inner wall of the casing.

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