Motor

Abstract

The present invention relates to a motor, comprising a housing and, arranged in the housing, a stator assembly and a rotor assembly. The stator assembly comprises a stator and a stator winding, the stator winding being electrically connected at an axial end part to a printed circuit board assembly. The printed circuit board assembly is electrically connected to a motor plug located on the outer side of the housing, and comprises a first printed circuit board and a second printed circuit board which are axially spaced apart from each other and electrically connected to each other. The first printed circuit board and the second printed circuit board each comprise a protruding portion extending into a receiving chamber of the motor plug. The motor of the present invention uses the two printed circuit boards axially spaced apart from each other, and each printed circuit board has the protruding portion extending into the motor plug, such that even if the motor has a small outer diameter size, great power and a larger working current, the space arrangement requirements of various electronic devices can also be met, and wiring can be also made to meet the specification of the automobile industry.

Description

motor Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a motor comprising an improved printed circuit board assembly. Background Art

[0002] With the development of science and technology, in order to meet the needs of automobile users as much as possible and improve the user's comfort, more and more functions are integrated into automobiles. In order to realize these functions, motors, especially brushless motors, are widely used in the automotive field.

[0003] A brushless motor typically consists of a stator assembly and a rotor assembly. The stator assembly includes a stator and stator windings wound around the stator. The stator windings are electrically connected to a printed circuit board assembly (PCBA) to achieve torque output and signal transmission. Most existing brushless motor designs require three-phase winding control. When high-power circuitry is incorporated, not only six relatively large MOSFET transistors are required, but also a large main control chip and external supporting circuitry must be placed on the printed circuit board (PCB). Considering the space required for both, the PCB must provide at least approximately 16mm x 16mm of space. However, when this design requirement arises for a relatively small motor (e.g., one with an outer diameter less than 40mm), high power, and high operating current, and especially when the PCB layout must comply with automotive industry standards and the rotor shaft must pass through the center of the PCB, achieving these functions in a small motor design with a single-layer PCB is difficult.

[0004] In particular, to meet automotive industry regulations and ensure that the EMC testing of brushless motors used in automobiles meets CISPR25 Class 5 requirements, it is usually necessary to place one or even multiple relatively large filter capacitors in the PCBA to meet filtering and EDS requirements, thereby placing greater demands on the wiring space that the PCBA can provide.

[0005] Therefore, it is necessary to propose a new motor structure that can integrate the main control chip and inverter circuit into the motor body even when limited by the small size of the motor, while also allowing the installation of large-capacity filter capacitors and filter circuit designs to achieve the required filtering function. Summary of the Invention

[0006] The present invention is proposed against this background. Specifically, the present invention provides a motor comprising a housing and a stator assembly and a rotor assembly located within the housing. The stator assembly includes a stator and a stator winding wound around the stator. The stator winding is electrically connected to a printed circuit board assembly at one axial end. The printed circuit board assembly is electrically connected to a motor plug located outside the housing and includes a first printed circuit board and a second printed circuit board arranged and electrically connected to each other at a distance in the axial direction. The first printed circuit board and the second printed circuit board each include a protrusion that extends into a receiving cavity of the motor plug.

[0007] According to an embodiment of the present invention, the first printed circuit board and the second printed circuit board each further include a main body portion connected to the protruding portion and located within the housing, wherein the main body portion is provided with a central through hole for the rotor shaft of the rotor assembly to pass through.

[0008] According to one embodiment of the present invention, the first printed circuit board carries a filter circuit; and the second printed circuit board carries a main control circuit and an inverter circuit of the motor.

[0009] According to one embodiment of the present invention, the motor plug includes a plug body defining the receiving cavity, wherein three slots are provided in the receiving cavity, wherein one end of each of the positive pin, the negative pin and the signal pin is press-fitted (for example, interference fit is achieved through an extrusion process) in a corresponding slot among the three slots.

[0010] According to one embodiment of the present invention, the other ends of the positive pin and the negative pin extending from the corresponding slots are respectively inserted through the corresponding receiving holes of the first printed circuit board and are fixedly connected to the first printed circuit board; the other ends of the signal pin extending from the corresponding slots are sequentially inserted through the corresponding receiving holes in the first printed circuit board and the second printed circuit board and are fixedly connected to the first printed circuit board and the second printed circuit board.

[0011] According to one embodiment of the present invention, a first pin and a second pin for conducting current filtered by the filter circuit are further fixed on the first printed circuit board, and the ends of the first pin and the second pin extending from the first printed circuit board are respectively inserted through corresponding receiving holes of the second printed circuit board and fixedly connected to the second printed circuit board.

[0012] According to one embodiment of the present invention, a fixing pin for providing a positioning and fixing function is further fixed on the first printed circuit board, and one end of the fixing pin extending from the first printed circuit board is inserted through the corresponding receiving hole of the second printed circuit board and fixedly connected to the second printed circuit board.

[0013] According to one embodiment of the present invention, the fixing points of the first pin, the second pin, the fixed pin and the signal pin on each printed circuit board are approximately triangular, so that the second printed circuit board can maintain a stable spaced relationship relative to the first printed circuit board.

[0014] According to one embodiment of the present invention, the motor plug further comprises a plug cover, which is snap-fitted to the plug body via a snap-fit ​​structure to encapsulate the protruding portions of the first and second printed circuit boards within the receiving cavity; the main bodies of the first and second printed circuit boards are encapsulated within the housing via the end cover of the motor.

[0015] According to one embodiment of the present invention, a through hole is provided on the first printed circuit, in which a fixed portion of a grounding spring is received, and a flexible portion of the grounding spring located outside the through hole abuts against the housing to achieve grounding.

[0016] Compared with the existing technology, especially in the design of small-sized motors, the technical solution according to the present invention can achieve at least one of the following technical effects: through two PCB boards, the main control chip and the inverter circuit can be integrated into the motor housing. At the same time, by extending the two PCB boards out of the motor housing and entering the receiving cavity of the motor plug, the space of the motor plug can be fully utilized, which not only can realize high-current drive, the selection of large-sized main control units, and reasonable automotive-grade PCB wiring, but also allows the placement of large-capacity filter capacitors and filter circuit designs that can adapt to high power. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other features and advantages of the present invention will become more readily understood through the following description with reference to the accompanying drawings, in which:

[0018] FIG1 shows a schematic structural diagram of a motor according to the present invention;

[0019] 2a and 2b show the structure of a printed circuit board assembly installed in the motor shown in FIG1 in a perspective view and a side view, respectively;

[0020] 3a and 3b are schematic structural diagrams showing a first printed circuit board and a second printed circuit board constituting the printed circuit board assembly in FIG. 2a and FIG. 2b , respectively;

[0021] FIG4 a shows a perspective schematic diagram of the printed circuit board assembly and the motor plug shown in FIG2 a and FIG2 b being assembled together;

[0022] FIG4 b is a partially exploded schematic diagram showing the printed circuit board assembly and the motor plug shown in FIG2 a and FIG2 b when assembled together; and

[0023] FIG5 shows a perspective schematic diagram of a plug body of a motor plug, wherein a positive electrode pin, a negative electrode pin and a signal pin are fixedly arranged in a receiving cavity of the plug body.

[0024] All drawings are only schematic and are not necessarily drawn to scale. In addition, they only show those parts necessary for explaining the present invention, and other parts are omitted or only mentioned. That is, in addition to the parts shown in the drawings, the present invention may also include other parts. DETAILED DESCRIPTION

[0025] In the following description, many specific details are set forth in order to enable those skilled in the art to more fully understand the present invention. However, it will be apparent to those skilled in the art that the present invention may be implemented without some of these specific details. The following various aspects, features, embodiments and advantages are for illustrative purposes only and should not be regarded as elements or limitations of the claims unless expressly set forth in the claims. Terms such as "first" and "second" are used below to describe the elements of the present application. These terms are only used to distinguish between the various elements and are not intended to limit the nature, sequence, order or number of these elements. In addition, it should be noted that in this specification, technical features that are identical and / or functionally identical are referred to by the same or similar figure marks.

[0026] As mentioned in the background technology, in the existing motor design, only a single printed circuit board located in the motor housing is usually provided at one axial end of the stator winding, which usually has a shape that matches the cylindrical shape of the motor housing (such as a circle). However, in small-sized motors (such as motors with an outer diameter of less than 40 mm), when the motor power and operating current are relatively large, the copper layer on the printed circuit board is usually wider, and a larger safety distance needs to be maintained between the electronic components, which undoubtedly increases the difficulty of routing and arranging components in small-sized motors. In addition, in order to be able to integrate the main control chip and the inverter circuit into the interior of the housing at the same time, while also allowing the placement of large-capacity filter capacitors and filter circuit designs that adapt to high power (for example, to meet the requirements of the automotive industry specifications for EMC), the single printed circuit board design in the prior art is obviously unable to meet the layout requirements of electronic components.

[0027] To this end, the present invention proposes an improved solution, which solves the problems of limited space for electronic component layout and difficult wiring by integrating a high-power drive PCBA into a miniature small-sized motor.

[0028] In the motor structure design of the present invention, it is proposed to use two PCB boards arranged at a distance from each other in the axial direction of the motor to jointly perform the functions of driving the motor and filtering. At the same time, by extending both PCB boards out of the motor housing and into the receiving cavity of the motor plug, the space in the motor plug is fully utilized, completing the routing of wires and the layout of electronic components in a small space.

[0029] Specifically, Figure 1 shows a schematic diagram of the structure of a motor according to the present invention. The present invention primarily relates to small-sized motors (particularly brushless motors), for example, motors having an outer diameter A less than 40 mm, such as 20-38 mm, and an axial length B of 40-100 mm. This is not intended to limit the application of the present invention to motors of other sizes.

[0030] The motor 1 includes a housing 10, a stator assembly and a rotor assembly located within the housing 10, and a motor plug 20 located outside the housing 10 and intended to be connected to a customer plug and, in turn, a power source. The stator assembly includes a stator and a stator winding wound around the stator. The stator winding is electrically connected at one axial end to a printed circuit board assembly (not shown in FIG. 1 ), which is electrically connected to the motor plug 20.

[0031] 2a and 2b show the structure of an improved printed circuit board assembly 30 installed in the motor shown in FIG. 1 in a perspective view and a side view, respectively.

[0032] Unlike conventional single-PCB designs, the printed circuit board assembly (PCB) 30 of the present invention comprises two electrically connected PCBs 31 and 32, spaced apart in the axial direction. One PCB can be designed for the motor's main control and inverter circuits, while the other can be designed for filtering circuits meeting CISPR 25 Class 5 requirements. The distance F between the two PCBs (see Figure 2b) is preferably 3-10 mm. This distance can be adjusted based on the specific requirements of the motor design.

[0033] Continuing to refer to Figures 3a and 3b, they respectively show the structural schematic diagrams of the two printed circuit boards constituting the printed circuit board assembly 30 in Figures 2a and 2b. Figure 3a shows a first printed circuit board 31 carrying a filter circuit. As shown in Figure 2a, the filter circuit is provided with three large-capacity filter capacitors 311. Of course, other numbers and sizes of filter capacitors can also be selected according to the power size. Figure 3b shows a second printed circuit board 32 carrying the main control circuit and inverter circuit of the motor. For example, a main control chip and six Mosfet transistors are carried on the surface of the second printed circuit board 32 facing the first printed circuit board 31, and three Hall sensors 321 (see Figure 4b) are carried on the other opposite surface. These Hall sensors 321 can be used to detect the rotational position accuracy of the rotor shaft, etc.

[0034] As can be seen in Figures 3a and 3b, the first and second printed circuit boards have substantially the same appearance. Each printed circuit board comprises a main portion 31a, 32a and protruding portions 31b, 32b extending from the main portion. The main portion is located within the motor housing 10, while the protruding portions extend outside the motor housing and are received in the receiving cavity of the motor plug 20. This fully utilizes the space within the motor plug 20, freeing up more room for the main portion to accommodate a large main control unit and filter circuits, while also meeting automotive-grade wiring requirements.

[0035] As shown in Figures 3a and 3b, to accommodate the cylindrical shape of the motor housing, the main body is preferably roughly circular, with an outer diameter C preferably between 18 and 36 mm. For example, when the motor's outer diameter is 36 mm, the printed circuit board's outer diameter C is approximately 33.8 mm. Furthermore, the main body is provided with a central through-hole for the rotor shaft of the rotor assembly to pass through. The inner diameter C1 of this central through-hole is within 12 mm. Furthermore, the protruding portion connected to the main board is designed to be roughly rectangular, with a width D of 10 to 28 mm. In particular, a width D of 17 mm can generally meet the design requirements of a large 7 mm x 7 mm main control unit and the dimensional space requirements of external circuitry. Furthermore, the height E of the protruding portion's outermost edge from the center of the central through-hole can be selected to be 16 to 30 mm. Of course, these dimensions can be adjusted and selected based on the actual motor structure.

[0036] Figures 4a and 4b respectively illustrate a perspective view of the printed circuit board assembly 30 and the motor plug 20 shown in Figures 2a and 2b assembled together. The motor plug 20 is located outside the housing 10. Referring particularly to Figure 4b, the motor plug 20 includes a plug body 21 defining a receiving cavity 211. As can be seen, the protruding portions of both printed circuit boards are inserted into the receiving cavity 211 of the motor plug 20. The motor plug 20 also includes a plug cover 22, which snaps into engagement with the plug body 21 via a snap-fit ​​structure (see Figure 4a), thereby enclosing the protruding portions of the first and second printed circuit boards 31, 32 within the receiving cavity 211. Furthermore, the main bodies of the first and second printed circuit boards 31, 32 are enclosed within the motor housing 10 via the motor's end caps.

[0037] See Figure 5 in particular, which shows a perspective schematic diagram of the plug body 21 of the motor plug 20. A positive pin 212, a negative pin 213, and a Lin or Can signal pin 214 are fixedly disposed within the receiving cavity 211 of the plug body 21. These pins can be formed as a single component with the motor plug 20 through an overmolding process and then soldered to the two printed circuit boards. Alternatively, these pins can be press-fitted into pre-reserved slots in the motor plug and then soldered to the two printed circuit boards to form a single, integrated component.

[0038] Specifically, during the assembly of the electrode plug 20 and the printed circuit board assembly 30, one end of the positive and negative pins 212 and 213 (intended to mate with the client plug) can first be press-fitted into corresponding slots in the electrode plug 20. The other ends extending from the corresponding slots are then inserted through corresponding receiving holes in the first printed circuit board 31 carrying the filter circuit and fixedly connected to the first printed circuit board 31, for example, by soldering. One end of the Lin or Can signal pin 214 (intended to mate with the client plug) is press-fitted into the corresponding slot in the electrode plug 20. The other ends extending from the corresponding slots are then inserted through corresponding receiving holes in the first printed circuit board 31 and the second printed circuit board 32 carrying the main control circuit, etc., and fixedly connected to the first and second printed circuit boards 31 and 32, for example, by soldering. Ultimately, the assembly shown in Figures 4a and 4b is formed.

[0039] Referring to Figures 2a and 4b , the first printed circuit board 31 is also secured with a first pin 312 and a second pin 313 for conducting the current filtered by the filter circuit. The ends of the first pin 312 and the second pin 313 extending from the first printed circuit board 31 are respectively inserted through corresponding receiving holes in the second printed circuit board 32 and are thus fixedly connected to the second printed circuit board 32. Furthermore, a fixing pin 314 is also secured to the first printed circuit board 31 for positioning and securing the current. The ends of the fixing pin 314 extending from the first printed circuit board 31 are inserted through corresponding receiving holes in the second printed circuit board 32 and are thus fixedly connected to the second printed circuit board 32.

[0040] It should be known that the fixed connection mentioned above can be carried out in a suitable manner known in the prior art, such as soldering connection. Of course, other possible connection methods besides soldering connection can also be used, such as press-fitting of pins with metallized receiving holes.

[0041] To more easily illustrate the relative positional relationship between the various pins secured to the first printed circuit board 31 and the various pins secured to the motor plug 20, FIG2a specifically illustrates the positive pin 212, negative pin 213, and signal pin 214 secured to the receiving cavity 211 of the motor plug 20. As shown in FIG2a, the respective securing points of the first and second pins 312, 313, fixed pin 314, and signal pin 214 on each printed circuit board form a roughly triangular shape (where the first and second pins, since they are adjacent to each other, can be considered a vertex of the triangle). This allows the second printed circuit board 32 to maintain a stable, spaced relationship relative to the first printed circuit board 31.

[0042] In addition, a through hole is provided on the first printed circuit 31 , in which a fixed portion of the grounding spring 315 is received. The flexible portion of the grounding spring 315 outside the through hole abuts against the motor housing 10 to achieve effective grounding.

[0043] When the PCB assembly discussed above is installed in the motor housing, the PCB assembly can be electrically connected to the stator windings, such as the three-phase windings, via a connection structure. For example, the coils of each phase winding are electrically connected to the PCB assembly to achieve torque output and signal transmission. Specifically, as shown in FIG3b , the second PCB 32 carrying the main control circuit is provided with three through-holes 322 spaced 60 degrees apart circumferentially. These three through-holes 322 can be tin-plated holes, designed to press-fit with three contact sections, such as those in the form of fisheye pins, of the corresponding three-phase windings on the connection structure to achieve electrical connection. Furthermore, a separate tin-plated through-hole 323 is provided on the second PCB 32, designed to press-fit with a common terminal contact section, such as those in the form of fisheye pins. When achieving a press-fit connection between the contact sections of the connection structure of the printed circuit board assembly and the stator winding, four radial notches 316 are preferably provided on the first printed circuit board 31, so that a pressing tool can pass through the radial notches and rest against the second printed circuit board 32, thereby pressing it toward the contact section to be connected thereto, and finally completing the electrical connection between the printed circuit board assembly and the stator winding.

[0044] The motor according to the present invention utilizes two printed circuit boards and each printed circuit board has a protruding portion extending into the motor plug. This allows the space requirements for arranging various electronic components to be met, even when the motor outer diameter is relatively small, the motor power is relatively large, and the motor operating current is relatively large. Furthermore, the wiring can comply with automotive industry standards.

[0045] It will be apparent to those skilled in the art that various modifications and variations may be made to the embodiments disclosed above without departing from the scope or spirit of the present invention. Other embodiments of the present invention will be apparent to those skilled in the art from the practice of the invention disclosed in this specification. This specification and the examples disclosed herein should be considered as illustrative only, and the true scope of the present invention is specified by the appended claims and their equivalents.

Claims

1. A motor, comprising a housing and a stator assembly and a rotor assembly located within the housing, the stator assembly including a stator and a stator winding wound around the stator, the stator winding being electrically connected to a printed circuit board assembly at an axial end, characterized in that, The printed circuit board assembly is electrically connected to a motor plug located outside the housing, and includes a first printed circuit board and a second printed circuit board which are electrically connected to each other and arranged at intervals in the axial direction. The first printed circuit board and the second printed circuit board each include a protruding portion extending into a receiving cavity of the motor plug.

2. The motor according to claim 1, characterized in that, The first printed circuit board and the second printed circuit board each further include a main body portion located inside the housing and connected to the protruding portion. The main body portion is provided with a central through hole for the rotor shaft of the rotor assembly to pass through.

3. The motor according to claim 2, characterized in that, The first printed circuit board carries a filter circuit; the second printed circuit board carries a main control circuit and an inverter circuit of the motor.

4. The motor according to claim 3, characterized in that, The motor plug includes a plug body defining the receiving cavity. Three slots are provided in the receiving cavity. One end of each of the positive pin, the negative pin and the signal pin is respectively press-fitted into a corresponding slot of the three slots.

5. The motor according to claim 4, characterized in that The other ends of the positive pin and the negative pin extending out of the corresponding slots are respectively inserted through corresponding receiving holes of the first printed circuit board and fixedly connected to the first printed circuit board; the other end of the signal pin extending out of the corresponding slot is sequentially inserted through corresponding receiving holes of the first printed circuit board and the second printed circuit board and fixedly connected to the first printed circuit board and the second printed circuit board.

6. The motor according to claim 5, characterized in that, A first pin and a second pin for conducting the current filtered by the filter circuit are also fixed on the first printed circuit board. The ends of the first pin and the second pin extending out of the first printed circuit board are respectively inserted through corresponding receiving holes of the second printed circuit board and fixedly connected to the second printed circuit board.

7. The motor according to claim 6, characterized in that, A fixed pin for providing a positioning and fixing function is also fixed on the first printed circuit board. The end of the fixed pin extending out of the first printed circuit board is inserted through a corresponding receiving hole of the second printed circuit board and fixedly connected to the second printed circuit board.

8. The motor according to claim 7, characterized in that, The fixing points of the first pin, the second pin, the fixed pin and the signal pin on each printed circuit board are approximately triangular, so that the second printed circuit board can stably maintain a spaced-apart relationship relative to the first printed circuit board.

9. The electric machine according to any one of claims 4 to 8, characterized in that The motor plug further includes a plug cover. The plug cover is snap-fitted to the plug body through a snap structure to encapsulate the protruding portions of the first printed circuit board and the second printed circuit board in the receiving cavity. The main body portions of the first printed circuit board and the second printed circuit board are encapsulated in the housing by an end cover of the motor.

10. The electric machine according to any one of claims 1 to 8, characterized in that, A through hole is provided in the first printed circuit. A fixed portion of a ground spring is received in the through hole. A flexible portion of the ground spring located outside the through hole abuts against the housing to achieve grounding.

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