Brushless motor for power tool

Abstract

The utility model relates to a brushless motor for a power tool, and belongs to the technical field of tools. The motor comprises a stator and a rotor. The rotor comprises a rotor body embedded with a magnet, and two ends of the rotor body respectively extend out of a rotor shaft; the stator is composed of a cylindrical winding frame made of an insulating material and a stator iron core wrapping the winding frame. One end face of the winding frame is provided with a card inserting structure of at least three wiring terminals and a fixing structure of connecting pieces. One end of the wiring terminal is a tangential power supply wire fixing end, and the other end is a winding wire winding end; the card holder is provided with a card inserting end extending downwards. The motor is simple in structure and convenient to assemble, and an external lead is led out in the tangential direction, so that the axial space is saved.

Description

Technical Field

[0001] This utility model relates to a brushless motor, and more particularly to a brushless motor for power tools, belonging to the field of power tool technology. Background Technology

[0002] US Patent No. 11646626B discloses a brushless motor for power tools, including a stator and a rotor rotatably housed within the stator. The rotor includes a rotor shaft, a rotor body mounted on the rotor shaft and including axial slots, a permanent magnet disposed within the axial slots, and a rotor end cap disposed at the end of the rotor body to axially retain the permanent magnet within the slots. The rotor end cap includes an outer planar portion that contacts the end of the rotor body, and ribs extending at an angle from the outer planar portion toward a central portion, forming an opening therebetween to allow air to pass between adjacent openings that are in thermal contact with the end of the rotor body.

[0003] European Patent EP2675041 also discloses a brushless motor for power tools, comprising a housing and a motor housed within the housing. The motor includes a stator assembly and a rotor pivotally arranged within the stator assembly. The stator assembly includes a lamination stack defining magnetic poles extending radially toward the center of the lamination stack, magnetic pole teeth extending laterally relative to the pole ends, and stator slots formed between adjacent magnetic poles. The stator assembly also includes excitation windings wound on the magnetic poles. Non-conductive tooth damper inserts are longitudinally arranged in the stator slots between adjacent excitation windings, each tooth damper insert including a radially outer end contacting the outer wall of the slot and a radially inner end arranged at the slot opening end and engaging the side edges of two opposing teeth within the slot.

[0004] The aforementioned existing technology not only has a relatively complex lead wiring structure during assembly, but also occupies axial space due to the axial extension of external wires. In addition, the separate assembly of the front and rear winding frames inevitably leaves a certain assembly gap, which poses a safety hazard for BLAC high-voltage appliances with strict electrical distance requirements. Utility Model Content

[0005] The purpose of this utility model is to address the shortcomings of the existing technology by proposing a simple, space-saving brushless motor for power tools through structural improvements.

[0006] To achieve the above objectives, the brushless motor for power tools of this utility model includes:

[0007] Includes a stator and a rotor rotatably housed within the stator;

[0008] The rotor includes a rotor body with embedded magnets, and rotor shafts extend from both ends of the rotor body;

[0009] The stator consists of an insulated cylindrical winding frame and a stator core encased in the winding frame;

[0010] One end face of the winding frame has a plug-in structure with at least three terminals and a fixing structure for the connecting piece;

[0011] One end of the terminal block is a tangential power supply fixed wire end, and the other end is a winding wire end; it also has a downward-extending plug-in end.

[0012] During assembly, one end of each of the three windings of the brushless motor is electrically connected to the connecting piece, and the other end of each of the three windings is electrically connected to the winding end of each of the three terminals, thus facilitating the connection of the three-phase power leads from the circuit board. It is readily apparent that, compared to existing technologies, this invention has a simpler structure, is easier to assemble, and features tangentially led-out external wires, thereby saving axial space.

[0013] A further improvement of this utility model is that the connecting piece is arc-shaped and adapted to the end face of the winding frame, and has at least three winding connection bends. Attached Figure Description

[0014] The present invention will be further described below with reference to the accompanying drawings.

[0015] Figure 1 This is a three-dimensional exploded structural diagram of Embodiment 1 of this utility model.

[0016] Figure 2 yes Figure 1 A three-dimensional schematic diagram of the stator.

[0017] Figure 3 yes Figure 1 A three-dimensional structural diagram of the winding frame.

[0018] Figure 4 yes Figure 1 A three-dimensional structural diagram of the intermediate terminal block.

[0019] Figure 5 yes Figure 1 A three-dimensional structural diagram of the connecting piece.

[0020] Figure 6 yes Figure 1 A cross-sectional view of the rotor in the embodiment. Detailed Implementation Example 1

[0021] The brushless motor used in the power tool in this embodiment is as follows: Figure 1 The device includes a stator 1 and a rotor 2 rotatably housed within the stator. The rotor 2 (see...) Figure 6The rotor body 2-1 in the middle section is inlaid with several magnets 2-2, and rotor shafts 2-3 extend from both ends of the rotor body 2-1. The stator 1 consists of an insulating cylindrical winding frame 1-1 and a stator core 1-2 covering the winding frame 1-1. It is manufactured using an integrated injection molding process, making the core 1-2 and the plastic cylindrical winding frame 1-1 a single unit. Figure 2 The overall design shown completely avoids the security risks present in existing technologies.

[0022] The specific structure of winding frame 1-1 is as follows: Figure 3 As shown, two ends form outward flanges 1.7 that fasten to the ends of the iron core. There are six spacer cylinder wall plates 1.6 connecting the two outward flanges. Between adjacent cylinder wall plates 1.6, an inwardly protruding winding ring 1.3 is formed. The middle of the winding ring 1.3 forms a cavity 1.5 to accommodate the iron core boot teeth 1-3. The inner end of the winding ring 1.3 extends circumferentially outward from the wire-blocking piece 1.2. The opposite ends of adjacent wire-blocking pieces 1.2 are respectively opened with slots for inserting connecting strips 3, so that after the winding of each winding ring is completed, each wire-blocking piece can form a closed inner ring.

[0023] The outer flange 1.7 at one end of the winding frame has three spaced protrusions 1.4, each with a snap-fit ​​hole on its end face, thus forming the snap-fit ​​structure of the terminal 4. In addition, it has three spaced protrusions 1.1, forming a fixing structure corresponding to the small holes on the connecting piece 5.

[0024] Terminal 4, for example Figure 4 As shown, one end is a tangential power supply fixing end 4-2, which has two pairs of inwardly rolled buckles, used to fix the insulation part of the power supply lead 6 and the conductor part after the insulation layer is stripped, respectively, to achieve reliable fixing and electrical connection; the other end is a winding end forming a hook head 4-3, used to wind one end of the winding to achieve electrical connection; in addition, the terminal also has a downwardly extending insertion end 4-1 with a tapered trapezoidal outer end, used to insert into the insertion hole of the winding frame for positioning.

[0025] Connecting piece 5, as Figure 5 As shown, it is an arc shape adapted to the end face of the winding frame, with three small holes corresponding to the protrusions, and three necked bend ends 5-1 for connecting the windings, which facilitates the electrical connection of the other end of each winding.

[0026] During assembly, use three terminals to secure the insulation and conductors of the three power leads, then insert them into the locking holes of the winding frame for positioning; snap the small hole of the connecting piece into the protrusion of the winding frame for positioning. Next, wind one end of each of the three windings of the brushless motor around the winding end of the hook, soldering if necessary to establish an electrical connection. Then, wind the other end of each winding around the necked section of the bend, soldering if necessary; this easily completes the required assembly and wiring.

[0027] Experiments show that this embodiment has the following advantages:

[0028] 1. The wire exit direction is parallel to the motor end face, which greatly saves the axial space of the motor;

[0029] 2. The terminal face is offset from the wire lead to facilitate the application of normal pressure and fixation of the lead;

[0030] 3. The wiring terminals and winding frame are interlocked for easy assembly and reliable positioning;

[0031] 4. The inward-rolling snap-fit ​​structure of the terminal block facilitates automatic crimping of the wires and terminals, achieving a reliable electrical connection without the need for spot welding or soldering.

[0032] 5. The winding structure of the terminals and connecting pieces facilitates the electrical connection of the winding leads.

[0033] In addition to the embodiments described above, this utility model may have other implementations. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by this utility model.

Claims

1. A brushless motor for power tools, comprising a stator (1) and a rotor (2) rotatably housed within the stator; The rotor comprises a rotor body (2-1) inlaid with magnets (2-2), and rotor shafts (2-3) extend from both ends of the rotor body; characterized in that: The stator consists of an insulating cylindrical winding frame (1-1) and a stator core (1-2) covering the winding frame; One end face of the winding frame has a plug-in structure with at least three terminals (4) and a fixing structure for the connecting piece (5); One end of the terminal block is a tangential power supply fixed wire end (4-2), and the other end is a winding wire end; it also has a downward-extending plug-in end (4-1).

2. The brushless motor for a power tool according to claim 1, characterized by: The connecting piece is arc-shaped to fit the end face of the winding frame and has at least three winding connection bends.

3. The brushless motor for power tools according to claim 2, characterized in that: The winding frame has outward flanges at both ends that fasten to the ends of the iron core. There are several spacer cylinder plates connecting the outward flanges at both ends, and inwardly protruding winding rings are formed between adjacent cylinder plates.

4. The brushless motor for a power tool according to claim 3, characterized by: The inner end of the winding ring extends circumferentially to form a wire-blocking piece. The opposite ends of adjacent wire-blocking pieces are respectively provided with slots for inserting connecting strips. After the winding of each winding ring is completed, each wire-blocking piece forms a closed inner ring.

5. The brushless motor for a power tool according to claim 4, characterized by: The tangential power supply fixing end of the terminal block is provided with two pairs of inward-rolling clips, which are used to fix the insulation part and the conductor part of the power supply lead, respectively.

6. The brushless motor for a power tool according to claim 5, characterized by: The winding end of the terminal block forms a hook, which is used to wind one end of the winding to achieve electrical connection.

7. The brushless motor for power tools according to claim 6, characterized by: The outer end of the insertion card of the terminal block is tapered trapezoidal, which is used for positioning when inserted into the insertion card hole of the winding frame.

8. The brushless motor for power tools according to claim 7, characterized by: The bent end of the connecting piece has a necked-down bent end, which is used to achieve an electrical connection with the winding.

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