Electric power tool and method of mounting motor thereof

Abstract

The present application provides a kind of electric tool, comprising: motor, including stator, rotor and fan, motor extends along first axis, stator includes stator core and stator winding wound on stator core, rotor includes motor shaft, rotor core and rotor winding wound on rotor core, fan is driven by motor shaft;Output shaft, motor drives output shaft output;Shell assembly;Power supply device for providing power supply for electric tool;Electric tool further includes heat conduction device that is sleeved to motor shaft, heat conduction device includes the first heat conduction part and the second heat conduction part being arranged at both ends thereof, first heat conduction part is arranged between motor shaft and fan, and first heat conduction part at least partially and fan surface is fitted, second heat conduction part is arranged between motor shaft and rotor winding, and rotor winding is wound on second heat conduction part.The present application also provides the motor installation method of the electric tool, and the electric tool effectively improves the heat dissipation efficiency and improves the heat dissipation stability.

Description

Technical Field

[0001] This invention relates to power tools and methods for installing their motors. Background Technology

[0002] Power tools, as commonly used auxiliary tools, play an important role in people's daily lives. However, the heat dissipation of the motor is a significant factor affecting the performance of power tools. When the motor is running, the heat generated causes the motor structure to heat up. When the internal temperature of the motor is too high, it will affect the magnetism of the internal magnets, thereby causing the motor to fail and resulting in the electronic equipment becoming inoperable or partially damaged.

[0003] During operation, the rotor of an electric motor generates a significant amount of heat that is difficult to dissipate. The relatively internal position of the rotor further complicates heat dissipation, causing heat to accumulate inside and exacerbating temperature rise. Traditional rotor structures result in a small effective heat dissipation area, and additional heat sinks can negatively impact rotor performance. Furthermore, due to the high speed of operation, these additional heat sinks are prone to detaching or separating from the rotor, affecting heat dissipation and interfering with normal motor operation. The traditional rotor structure and arrangement exacerbate heat dissipation difficulties, leading to excessively high internal temperatures and impacting machine performance. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the main objective of the present invention is to provide an electric tool that can improve heat dissipation efficiency and has stable heat dissipation performance, as well as a method for installing the motor of the electric tool.

[0005] To achieve the above-mentioned main objectives, an electric tool is provided, comprising: a motor including a stator, a rotor, and a fan, the motor extending along a first axis, the stator including a stator core and a stator winding wound around the stator core, the rotor including a motor shaft, a rotor core, and a rotor winding wound around the rotor core, the fan being driven by the motor shaft; an output shaft, the motor driving the output shaft to output; a housing assembly, the motor being disposed inside the housing assembly; a power supply device for providing power to the electric tool; the electric tool further comprising a heat-conducting device sleeved on the motor shaft, the heat-conducting device including a first heat-conducting part and a second heat-conducting part disposed at its two ends, the first heat-conducting part being disposed between the motor shaft and the fan, and the first heat-conducting part being at least partially in contact with the fan surface, the second heat-conducting part being disposed between the motor shaft and the rotor winding, and the rotor winding being wound around the second heat-conducting part.

[0006] Optionally, the motor also includes an insulating bracket that surrounds the motor shaft and is positioned between the motor shaft and the heat-conducting device.

[0007] Optionally, the fan includes: a fan shaft that passes through the fan and forms a mounting hole, and a first heat-conducting part that is fixedly connected to the fan shaft through the mounting hole; and fan blades disposed around the fan shaft.

[0008] Optionally, the length of the second heat-conducting part on the first axis is greater than or equal to 10 mm and less than or equal to 14 mm.

[0009] Optionally, the first and second heat-conducting parts are axial and sleeved on the outside of the insulating support, and the outer diameter of the first heat-conducting part is larger than the outer diameter of the second heat-conducting part.

[0010] Optionally, the wall thickness of the second heat-conducting part is greater than or equal to 0.8 mm and less than or equal to 1.2 mm.

[0011] Optionally, the first heat-conducting part and the insulating bracket extend through the fan shaft in the first axial direction.

[0012] Optionally, the length of the first heat-conducting part on the first axis is greater than or equal to 10.5 mm and less than or equal to 13.5 mm.

[0013] Optionally, the motor may also include a heat dissipation bracket partially disposed between the stator core and the stator windings, the heat dissipation bracket extending at least partially beyond the stator core and the stator windings.

[0014] To achieve the above-mentioned main invention objectives, a method for installing a motor in an electric tool is provided, comprising: installing an insulating bracket outside the motor shaft; assembling a rotor core and fitting a heat-conducting device onto the insulating bracket on the motor shaft; winding a rotor winding around a second heat-conducting portion of the heat-conducting device; assembling a stator core with stator windings and installing a commutator; and configuring a fan to fit around a first heat-conducting portion of the heat-conducting device, such that at least a portion of the fan contacts the first heat-conducting portion.

[0015] This invention provides an installation method for an electric tool and its motor. The heat-conducting device is partially installed inside a fan and partially wound around a rotor winding. Part of the heat generated by the motor rotor can be transferred to the fan through the heat-conducting device via thermal conduction. This increases the effective heat dissipation area of ​​the motor, and the airflow generated by the fan driven by the rotor disperses the heat inside the fan and the motor, thereby effectively improving heat dissipation efficiency, reducing the temperature rise inside the electric tool, and improving the stability of the electric tool's heat dissipation. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of the power tool according to the first embodiment of the present invention.

[0017] Figure 2 This is a cross-sectional view of the power tool according to the first embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of the structure of the motor according to the first embodiment of the present invention.

[0019] Figure 4 This is an exploded schematic diagram of the motor according to the first embodiment of the present invention.

[0020] Figure 5 This is a schematic diagram of the cooperation relationship between the fan and the heat conduction device according to the first embodiment of the present invention.

[0021] Figure 6 This is a schematic flowchart of the motor assembly method according to the first embodiment of the present invention.

[0022] Figure 7 This is a schematic diagram of the motor structure according to the second embodiment of the present invention. Detailed Implementation

[0023] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting the invention.

[0024] In the first preferred embodiment of the present invention, referring to Figure 1 This is a three-dimensional structural diagram of a power tool according to the first embodiment of the present invention. The present invention provides a power tool 100, which has good heat dissipation capabilities. The power tool 100 can be a lawnmower, mower, electric drill, angle grinder, hammer drill, pruning machine, chainsaw, etc., and is not limited to the above-mentioned types of power tools 100. The present invention also provides a motor 200 structure that can be applied to the above-mentioned power tool 100.

[0025] Figure 2 This is a cross-sectional view of a power tool according to the first embodiment of the present invention. In this embodiment, reference is made to... Figure 2The power tool 100 includes a motor 200, an output shaft 110, a housing assembly 120, and a power supply unit. The motor 200 is housed within the housing assembly 120 and drives the output shaft 110 to output workpieces. The power supply unit provides power to the power tool 100. Optionally, the power supply unit can be a battery pack, supplying power to the power tool 100 through a drive circuit connected to the motor 200. Alternatively, the power supply unit can be a power cord connected to the drive circuit, which will not be detailed here. Depending on its type, the power tool 100 may also include a tool chuck for holding tool accessories. For example, if the power tool 100 is an electric screwdriver, it includes a tool chuck for mounting various drill bits to match different fastening operations. If the power tool 100 is an angle grinder, it also includes a tool chuck for mounting grinding discs, which are rotated by the output shaft 110 to cut and grind workpieces. The specific working principle of the invention is explained below using an angle grinder as an example.

[0026] Figure 3 This is a schematic diagram of the structure of the motor according to the first embodiment of the present invention. Figure 4 This is an exploded view of the motor according to the first embodiment of the present invention. Please refer to... Figure 3 and Figure 4 The motor 200 includes a stator 210, a rotor 220, and a fan 230. The rotor 220 includes a rotor core 221, a rotor winding 222 wound around the rotor core 221, and a motor shaft 223. The motor shaft 223 extends along a first axis 101. The stator 210 includes a stator core 212 and a stator winding 211 wound around the stator core 212. In this embodiment, the rotor 220 is disposed within the stator 210 and sleeved on the motor shaft 223, and is fixedly connected to the motor shaft 223. A rotating magnetic field is generated by the stator 210 and acts on the rotor 220 to form a rotational torque. When the power tool 100 is running, it drives the motor shaft 223 to rotate. The fan 230 is mounted on the motor shaft 223. When the motor shaft 223 rotates, it drives the fan 230 mounted on the motor shaft 223 to rotate, generating a cooling airflow to dissipate heat from the motor 200 and the interior of the power tool 100.

[0027] The housing assembly 120 includes at least a grip for holding; if necessary, it also includes a motor housing for housing the motor 200. The power tool also includes a switch connected to a drive circuit for controlling the opening and closing of the drive circuit to control the operation of the power tool. Some power tools, such as angle grinders, also include a transmission mechanism connected to the output shaft 110 and connected via the transmission mechanism to the motor shaft 223 of the motor 200. The transmission mechanism is used to reduce the speed of the output shaft and includes a first gear and a second gear meshing with each other, the first gear and the second gear having a different gear ratio to allow the transmission mechanism to reduce speed.

[0028] The power tool 100 also includes a heat-conducting device 300 sleeved on the motor shaft 223. The heat-conducting device 300 includes a first heat-conducting part 310 and a second heat-conducting part 320 disposed at its two ends. The first heat-conducting part 310 is disposed between the motor shaft 223 and the fan 230, and at least partially in contact with the surface of the fan 230. The second heat-conducting part 320 is disposed between the motor shaft 223 and the rotor winding 222, and the rotor winding 222 is wound around the second heat-conducting part 320. The heat-conducting device 300 connects the fan 230 and the rotor 220 of the motor 200, so that when the power tool 100 is running, part of the heat generated by the motor 200 is transferred to the fan 230 through the heat-conducting device 300, thereby transferring the heat of the rotor 220 to the fan 230 through the heat-conducting device 300. The high-speed airflow around the surface of the fan 230 carries away the heat on the fan 230, thereby improving the heat dissipation power of the motor 200.

[0029] Figure 5 This is a schematic diagram illustrating the fit between a fan and a heat-conducting device according to a first embodiment of the present invention. The fan 230 includes a fan shaft 232 and fan blades 233 extending around the fan shaft 232. Preferably, the fan shaft 232 and fan blades 233 are integrally formed and made of the same material. The fan shaft 232 passes through the fan 230 and forms a mounting hole 234. The mounting hole 234 matches the shape of the heat-conducting device 300, thus fixing the heat-conducting device 300 and the fan 230 together. In one fit, the first heat-conducting part 310 is a non-cylindrical shaft shape. For example, the first heat-conducting part 310 has at least one flat surface on its sidewall, and the corresponding mounting hole 234 is designed to correspond to the structure of the first heat-conducting part 310. This allows the first heat-conducting part 310 to be inserted into the mounting hole 234, fixing the two together, and allowing them to rotate in unison at least in the direction of rotation around the first axis 101. See [reference needed] for details. Figure 5 The mounting hole 234 and the heat-conducting device 300 are fixedly connected by a flat fit. It is understood that the first heat-conducting part 310 and the fan 230 can also be fixedly connected by other methods, such as screw connection, other snap-fit ​​methods, or interference fit, which will not be detailed here. The arrangement ensures that the fan shaft 232 and the first heat-conducting part 310 are in close contact, thereby ensuring that the fan 230 can effectively receive the heat generated by the rotor 220. There are multiple fan blades 233, and there is a certain gap between the fan blades 233. The multiple fan blades 233 increase the effective heat dissipation area of ​​the fan 230 and increase the volume of the fan 230, so that the large amount of heat generated by the rotor 220 can be transferred into the fan 230 and quickly dissipated through the multiple fan blades 233.

[0030] The motor 200 also includes an insulating bracket 224, which surrounds the motor shaft 223 and is positioned between the motor shaft 223 and the heat-conducting device 300. The insulating bracket 224 at least partially covers the motor shaft 223, isolating the motor shaft 223 from the rotor 220 and thus preventing short circuits in the internal circuitry of the motor 200. The insulating bracket 224 includes an insulating shaft surrounding the motor shaft 223 and an extension bracket 2241 mounted on the insulating shaft. The extension bracket 2241 is used to fix and support the rotor core 221, allowing the rotor 220 to be mounted on the insulating bracket 224 and rotate integrally with the motor shaft 223. A fan 230 is mounted to one end of the motor shaft 223, and the heat-conducting device 300 is positioned between the fan 230 and the rotor 220. The first heat-conducting part 310 of the heat-conducting device 300 is located within the fan shaft 232, and the second heat-conducting part 320 of the heat-conducting device 300 extends towards the rotor 220 and is located within the rotor 220.

[0031] Specifically, the second heat-conducting part 320 is disposed between the rotor winding 222 and the insulating support 224, and the rotor winding 222 is wound around the second heat-conducting part 320. Thus, when the power tool 100 is running, the heat generated by the rotor winding 222 can be directly and quickly transferred to the second heat-conducting part 320, and then transferred to the fan 230 through the first heat-conducting part 310, which is in direct contact with the fan 230. The heat is then dissipated by the cooling airflow generated by the fan 230, thereby effectively improving heat dissipation efficiency. Furthermore, the connection between the fan 230 and the rotor 220 indirectly increases the heat dissipation surface area of ​​the rotor 220, increasing the heat exchange area between the rotor 220 and the air, thereby improving the heat exchange power of the rotor 220.

[0032] The stator core 212 includes a core base and a winding portion connected to the core base. The winding portion is used to wind the stator winding 211. The core base is preferably a hollow cylinder. The winding portions extend inward from the inner surface of the core base, and multiple winding portions are symmetrically distributed inside the core base. Specifically, the winding portion includes a winding section and a protective end. The protective end is formed at the end of the winding section and extends to both sides from the end of the winding section, so that the width of the protective end is greater than the width of the cross-section of the winding section. When the stator winding 211 is wound onto the core base, the protective end is used to intercept and fix the stator winding 211, and to protect the stator winding 211.

[0033] Preferably, a high heat dissipation material is used as the manufacturing material for the fan 230, such as some metallic materials like aluminum alloy and copper. Other high heat dissipation non-metallic materials such as graphite and carbon fiber can also be used. Materials with a heat dissipation coefficient higher than 110 W / (m·K) are selected as the main body material or part of the manufacturing material for the fan 230 to meet the heat dissipation requirements of the power tool 100, especially high-power power tools 100, during operation. Similarly, the heat conduction device 300 can also be made of a high heat dissipation material, such as metallic materials or carbon fiber, so that the heat generated by the rotor 220 can be transferred to the fan 230 in a timely manner through the heat conduction device 300, thereby further improving the heat dissipation efficiency of the motor 200. Optionally, a fan end cover 231 is also provided at one end of the fan 230 for relatively fixing the fan 230, and the fan end cover 231 is located at the other end of the fan relative to the first heat conduction part 210.

[0034] Specifically, to ensure that the heat generated by the rotor winding 222 and the rotor core 221 can be effectively transferred to the heat-conducting device 300, the length of the second heat-conducting part 320 on the first axis 101 is greater than or equal to 10 mm and less than or equal to 14 mm. The rotor winding 222 is wound around the second heat-conducting part 320, thereby increasing the contact area between the rotor winding 222 and the second heat-conducting part 320, and fully transferring the heat generated by the rotor winding 222 to the motor 200. To shorten the overall length of the motor 200 and prevent the power tool 100 from becoming too large due to the size of the motor 200, the length of the second heat-conducting part 320 on the first axis 101 does not exceed 14 mm, thus making the motor 200 compact. Preferably, the length of the second heat-conducting part 320 is 11 mm to 12 mm, ensuring the heat dissipation efficiency of the motor 200 while maintaining its compactness.

[0035] Furthermore, the first heat-conducting part 310 and the second heat-conducting part 320 are shaft-shaped and sleeved on the outside of the insulating bracket 224. The outer diameter of the first heat-conducting part 310 is larger than the outer diameter of the second heat-conducting part 320. Because the rotor core 221 is wound around the second heat-conducting part 320, the outer diameter of the second heat-conducting part 320 cannot be too large to prevent the rotor winding 222 wound around the second heat-conducting part 320 from protruding beyond the rotor 220 position, or causing the rotor 220 to collide with the stator 210 during rotation, thus damaging the structure of the motor 200. Specifically, the wall thickness L of the second heat-conducting part 320 is greater than or equal to 0.8 mm and less than or equal to 1.2 mm. Under the premise of ensuring the strength and heat transfer performance of the second heat-conducting part 320, the installation of the second heat-conducting part 320 inside the rotor 220 will not affect the performance of the motor 200, and effectively improves the heat dissipation efficiency inside the motor 200 and the power tool 100.

[0036] The insulating bracket 224 is directly sleeved on the motor shaft 223. The first heat-conducting part 310 is fixedly connected to the outside of the insulating bracket 224, and the fan 230 is fixed through the first heat-conducting part 310, so that the fan 230, the first heat-conducting part 310, the motor shaft 223, and the insulating bracket 224 rotate synchronously when the motor 200 is running. Preferably, the first heat-conducting part 310 and the insulating bracket 224 pass through the fan shaft 232 in the direction of the first axis 101, so that the first heat-conducting part 310 and the insulating bracket 224 are provided between the fan shaft 232 and the motor shaft 223, thereby ensuring that the fan 230 and the heat-conducting device 300 are in full contact, so that the heat generated by the rotor 220, especially the heat generated by the rotor winding 222, can be effectively transferred to the fan 230. Furthermore, the length of the first heat-conducting part 310 on the first axis 101 is greater than or equal to 10.5 mm and less than or equal to 13.5 mm, thereby ensuring the effective contact area between the first heat-conducting part 310 and the fan 230, so that the fan 230 can receive the heat transferred by the heat-conducting device 300 in a timely manner, thereby ensuring the heat dissipation effect of the power tool 100.

[0037] This invention improves the heat dissipation performance of the motor 200. Since the motor 200 of a high-power power tool 100 experiences a higher temperature rise during operation, it has a greater demand for efficient heat dissipation. The heat dissipation method of this invention effectively increases the heat dissipation rate of the motor 200, thereby ensuring the smooth operation of the high-power power tool 100. The motor 200 provided by this invention, while reducing its size, still meets the heat dissipation requirements of motors with a power rating of 2200W or less, thus improving the operating performance of the power tool 100.

[0038] Figure 6 This is a schematic flowchart of the motor assembly method according to the first embodiment of the present invention. (Refer to...) Figure 6 This invention provides an electric motor 200 and its assembly method. The electric motor 200 includes a stator 210, a rotor 220, and a fan 230. The rotor 220 includes a rotor core 221, a rotor winding 222 wound around the rotor core 221, and a motor shaft 223. The motor shaft 223 extends along a first axis 101. The stator 210 includes a stator core 212 and a stator winding 211 wound around the stator core 212. In this embodiment, the rotor 220 is disposed within the stator 210 and sleeved on the motor shaft 223, and is fixedly connected to the motor shaft 223. A rotating magnetic field is generated by the stator 210 and acts on the rotor 220 to form a rotational torque. When the power tool 100 is running, it drives the motor shaft 223 to rotate. The fan 230 is mounted on the motor shaft 223. When the motor shaft 223 rotates, it drives the fan 230 mounted on the motor shaft 223 to rotate, generating a cooling airflow to dissipate heat from the inside of the electric motor 200 and the power tool 100.

[0039] The power tool 100 also includes a heat-conducting device 300 sleeved on the motor shaft 223. The heat-conducting device 300 includes a first heat-conducting part 310 and a second heat-conducting part 320 disposed at both ends thereon. The first heat-conducting part 310 is disposed between the motor shaft 223 and the fan 230, and the first heat-conducting part 310 is at least partially in contact with the fan 230. The second heat-conducting part 320 is disposed between the motor shaft 223 and the rotor winding 222, and the rotor winding 222 is wound around the second heat-conducting part 320.

[0040] The following assembly method for the motor 200 is provided: S1: Install an insulating bracket 224 on the outside of the motor shaft 223; S2: Assemble the rotor core 221 and sleeve the heat-conducting device 300 on the outside of the insulating bracket 224 on the motor shaft 223; S3: Wind the rotor winding 222 around the heat-conducting device 300, specifically around the second heat-conducting part 320; S4: Assemble the stator core 212 with the stator winding 211 wound on it and install the commutator 225; S5: Install the fan 230 onto the motor shaft 223, such that the fan 230 sleeves and at least partially contacts the heat-conducting device 300. Specifically, the fan is arranged to sleeve the first heat-conducting part 310 of the heat-conducting device 300, and the fan at least partially contacts the first heat-conducting part 310.

[0041] Through the above steps, the heat-conducting device 300 is installed inside the rotor winding 222, allowing the heat generated by the rotor winding 222 during motor 200 operation to be transferred to the fan 230 through the wound heat-conducting device 300, effectively reducing the temperature drop of the motor 200 during operation. By installing and fixing the first heat-conducting part 310 of the heat-conducting device 300 inside the fan shaft 232, and using the second heat-conducting part 320 as the winding object of the rotor winding 222, the heat-conducting device 300 is stably connected and in close contact with both the fan 230 and the rotor 220, thereby ensuring a stable heat dissipation effect of the heat-conducting device 300. It will not easily detach or separate from the fan 230 and the rotor 220, avoiding a reduction in heat dissipation effect and a weakening of motor 200 performance.

[0042] In a second preferred embodiment of the present invention, a power tool is provided. Figure 7 This is a schematic diagram of the motor structure according to the second embodiment of the present invention, with reference to... Figure 7 The motor 200a includes a stator, a rotor, and a fan. The rotor includes a rotor core, a rotor winding wound around the rotor core, and a motor shaft extending along a first axis. The stator includes a stator core 211a and a stator winding 212a wound around the stator core 211a. A heat dissipation bracket 330 is disposed between the stator winding 212a and the stator core 211a to solve the problem of low thermal conductivity of the stator core affecting the heat dissipation of the stator winding and the stator core.

[0043] This embodiment is the same as the first preferred embodiment. The power tool also includes a heat-conducting device (not shown) sleeved on the motor shaft. The heat-conducting device includes a first heat-conducting part and a second heat-conducting part disposed at both ends thereon. The first heat-conducting part is disposed between the motor shaft and the fan, and at least partially in contact with the fan surface. The second heat-conducting part is disposed between the motor shaft and the rotor winding, and the rotor winding is wound around the second heat-conducting part. The heat-conducting device connects the fan and the motor rotor, so that when the power tool is running, a portion of the heat generated by the motor is transferred to the fan through the heat-conducting device 300.

[0044] A heat sink bracket 330 is inserted into and fixed to the stator core to improve the stator's heat dissipation efficiency. The stator core has at least one heat dissipation slot, which is adapted to the structure of the heat sink bracket 330, allowing the heat sink bracket 330 to be inserted into the stator core through the heat dissipation slot. The stator core has a first surface and a second surface, which are formed opposite to each other on both sides of the stator core, with the winding portion extending inward from the first surface. The heat dissipation slot is correspondingly disposed on the first surface and the second surface. The heat sink bracket 330 is correspondingly placed into the heat dissipation slot, such that the surface of the heat sink bracket 330 contacts the stator core and the coil winding.

[0045] The heat dissipation bracket 330 is located inside the heat dissipation slot and contacts the coil winding. During the operation of the motor 200, the high-temperature coil winding transfers heat to the heat dissipation bracket 330 through thermal conduction. Part of the heat dissipation bracket 330 is exposed to the air. When the motor 200 is running, the fan generates a high-speed airflow to dissipate the heat of the heat dissipation bracket 330, thereby quickly dissipating the heat generated by the stator core and stator winding.

[0046] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0047] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the present invention. The objectives of the present invention have been fully and effectively achieved. The functional and structural principles of the present invention have been shown and explained in the embodiments, and any modifications or variations of the embodiments of the present invention may be made without departing from the principles.

Claims

1. An electric tool, comprising: An electric motor includes a stator, a rotor, and a fan. The stator includes a stator core and a stator winding wound around the stator core. The rotor includes a motor shaft rotating along a first axis, a rotor core, and a rotor winding wound around the rotor core. The fan is driven by the motor shaft. The motor drives the output shaft to output; A housing assembly, wherein the motor is disposed inside the housing assembly; Power supply unit, used to provide power to power tools; The power tool is characterized in that: the power tool further includes a heat-conducting device sleeved on the motor shaft, the heat-conducting device includes a first heat-conducting part and a second heat-conducting part disposed at both ends thereon, the first heat-conducting part is disposed between the motor shaft and the fan, and the first heat-conducting part is at least partially in contact with the fan surface, the second heat-conducting part is disposed between the motor shaft and the rotor winding, and the rotor winding is wound around the second heat-conducting part; The length of the second heat-conducting part on the first axis is greater than or equal to 10 mm and less than or equal to 14 mm. The rotor winding is in direct contact with the circumferential surface of the second heat-conducting part so that the heat generated by the rotor winding is directly transferred to the second heat-conducting part.

2. The power tool as described in claim 1, characterized in that: The motor also includes an insulating bracket that surrounds the motor shaft and is disposed between the motor shaft and the heat-conducting device.

3. The power tool as described in claim 2, characterized in that: The fan includes: A fan shaft passes through the fan and forms a mounting hole, and the first heat-conducting part is fixedly connected to the fan shaft through the mounting hole; Fan blades are disposed on the circumference of the fan shaft.

4. The power tool as described in claim 3, characterized in that: The first and second heat-conducting parts are axial and sleeved on the outside of the insulating bracket, and the outer diameter of the first heat-conducting part is larger than the outer diameter of the second heat-conducting part.

5. The power tool as described in claim 4, characterized in that: The wall thickness of the second heat-conducting part is greater than or equal to 0.8 mm and less than or equal to 1.2 mm.

6. The power tool as described in claim 5, characterized in that: The first heat-conducting part and the insulating bracket extend through the fan shaft in the first axial direction.

7. The power tool as described in claim 6, characterized in that: The length of the first heat-conducting part on the first axis is greater than or equal to 10.5 mm and less than or equal to 13.5 mm.

8. The power tool as described in claim 3, characterized in that: The motor also includes a heat dissipation bracket partially disposed between the stator core and the stator winding, the heat dissipation bracket extending at least partially beyond the stator core and the stator winding.

9. A method for installing a motor in an electric tool, characterized in that: Install an insulating bracket on the outside of the motor shaft; The rotor core is assembled and the heat-conducting device is sleeved on the insulating bracket on the motor shaft, wherein the heat-conducting device includes a first heat-conducting part and a second heat-conducting part disposed at both ends thereon; The rotor winding is wound around the second heat-conducting part of the heat-conducting device, and the second heat-conducting part is disposed between the motor shaft and the rotor winding; Assemble a stator core with stator windings and install a commutator; The fan is configured such that it is sleeved outside the first heat-conducting part of the heat-conducting device, and the fan is at least partially in contact with the first heat-conducting part, wherein the first heat-conducting part is disposed between the motor shaft and the fan; The length of the second heat-conducting part on the first axis is greater than or equal to 10 mm and less than or equal to 14 mm. The rotor winding is in direct contact with the circumferential surface of the second heat-conducting part so that the heat generated by the rotor winding is directly transferred to the second heat-conducting part.

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