Electric tool

Abstract

The utility model discloses an electric tool. The electric tool comprises a motor used for providing power for the electric tool and comprising a stator and a rotor rotating relative to the stator; the power supply device is at least electrically connected with the motor; an output unit driven by the motor; the radial center of the stator is provided with a support member including a rim portion and a spoke portion. The electric tool and the motor thereof have good heat dissipation performance and can reduce weight and cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric power tools, for example to an electric power tool. BACKGROUND

[0002] Electric power tools are more environmentally friendly than engine tools, and thus are widely used. Electric power tools generally use motors to drive work. When the electric power tool is working, the motor generates heat. The greater the working current of the electric power tool, the more heat the motor generates, and the more serious the heating of the winding of the motor. When the temperature of the winding is high, the efficiency of the motor is reduced, the output capacity is insufficient, and other problems occur, so that the motor and the electric power tool cannot work normally.

[0003] This section provides background information relating to the present application, which can not necessarily be prior art. SUMMARY

[0004] An object of the present application is to solve or at least alleviate part or all of the above problems. To this end, the present application provides an electric power tool. In order to achieve the above object, the present application adopts the following technical solution:

[0005] An electric power tool, comprising: a motor for providing power to the electric power tool, the motor comprising a stator and a rotor rotating relative to the stator; a power supply device electrically connected to at least the motor; an output portion driven by the motor; and a support member comprising a rim portion and a spoke portion provided at a radial center of the stator.

[0006] In some embodiments, the electric power tool further comprises a housing formed with an accommodation space, and the output portion comprises a functional member; the motor is arranged in the accommodation space of the housing and drives the functional member to perform a corresponding function.

[0007] In some embodiments, the rotor is sleeved outside the stator, and the support member is arranged inside the stator and supports the stator.

[0008] In some embodiments, the support member is made of metal or modified plastic.

[0009] In some embodiments, the ratio of the outer diameter of the stator to the rotor is greater than or equal to 0.7.

[0010] In some embodiments, the pole arc coefficient of the rotor is greater than or equal to 0.6 and less than 1.

[0011] In some embodiments, the power density of the motor is greater than or equal to 2000W / kg.

[0012] In some embodiments, the stator comprises a stator core and a stator winding, the stator core has a plurality of radially extending teeth, and the stator winding is wound on the teeth; the teeth are not equally wide in the radial direction, wherein the width of the teeth is the width of the teeth in the direction perpendicular to the extension direction thereof.

[0013] In some embodiments, the ratio of the maximum width to the minimum width of the teeth is greater than 1 and less than or equal to 1.8.

[0014] In some embodiments, the rotor comprises a rotor core and a magnetic steel, the magnetic steel is fixed to the rotor core in a plastic-bonded manner.

[0015] In some embodiments, the motor further comprises a bracket, the stator and the rotor are sleeved on the bracket, the support is coaxially arranged with the bracket, and the bracket is formed with an air inlet and an air outlet through which the cooling airflow passes.

[0016] In some embodiments, the electric tool further comprises a fan, and the motor further has a motor housing, the motor housing is integrally formed with the fan.

[0017] In some embodiments, the rotor comprises a rotor core, and an inner wall of the motor housing is formed with a limiting boss for limiting the rotor core in the axial direction.

[0018] A chain saw comprises: a housing; a chain and a guide plate, the chain being arranged around the outer periphery of the guide plate, one end of the guide plate being supported on the housing and the other end extending out of the housing along the longitudinal direction of the housing; a motor for driving the chain to cut; and a position detection assembly for detecting the position of the rotor of the motor, the position detection assembly comprising a magnetic member and a position sensor; the magnetic member is arranged on one end of the output shaft of the motor, the housing has a wind guide portion for guiding the cooling airflow, and the position sensor is arranged on the wind guide portion.

[0019] In some embodiments, the output shaft end is provided with a mounting member on which the magnetic member is mounted, and the magnetic member is connected to the output shaft end through the mounting member.

[0020] In some embodiments, the mounting member is sleeved on the end of the output shaft away from the chain and the guide plate and has a mounting groove in which the magnetic member is embedded.

[0021] In some embodiments, the chain saw further comprises a fan arranged on the output shaft, the fan is located between the magnetic member and the motor in the axial direction of the output shaft, and the magnetic member is located between the position sensor and the fan.

[0022] In some embodiments, the projection of the magnetic member and the position sensor in the axial direction of the output shaft at least partially overlaps.

[0023] In some embodiments, the straight line on which the output shaft is located is substantially perpendicular to the plane on which the guide plate is located.

[0024] In some embodiments, the housing comprises a wind guide cover, and the wind guide portion is located on the wind guide cover.

[0025] In some embodiments, the wind guide cover is formed with a recess away from the motor, and the position sensor is arranged in the recess.

[0026] In some embodiments, the groove of the air guide shroud has openings through which circuit cables and cooling airflow can pass.

[0027] In some embodiments, the end of the output shaft with the magnetic element mounted extends at least partially into the groove.

[0028] In some embodiments, the chainsaw further includes a circuit board assembly and an oil reservoir, wherein the orthographic projections of the motor and the oil reservoir in a plane perpendicular to the guide plate substantially fall within the orthographic projection of the circuit board assembly in a plane perpendicular to the guide plate.

[0029] In some embodiments, the chainsaw's output power is greater than or equal to 1000W.

[0030] In some embodiments, the chain speed of the chainsaw is greater than or equal to 10 m / s.

[0031] In some embodiments, the power density of the motor is greater than 1000 W / kg.

[0032] In some embodiments, the outer diameter of the motor is greater than or equal to 50 mm.

[0033] In some embodiments, the motor includes a stator and a rotor that rotates relative to the stator, and a support member including a rim portion and a spoke portion is provided at the radial center of the stator.

[0034] The technical effects of this application include at least improving the heat dissipation performance of power tools and their motors. Attached Figure Description

[0035] Figure 1 This is a plan view of a chainsaw as one embodiment in this application;

[0036] Figure 2 yes Figure 1 The diagram shown is a plan view of the chainsaw after part of the casing has been removed.

[0037] Figure 3 yes Figure 1 A plan view of the circuit board assembly, oil reservoir, and motor in the chainsaw shown.

[0038] Figure 4 yes Figure 2 A cross-sectional view of part of the structure of the housing, air guide, motor and fan in the chainsaw shown;

[0039] Figure 5 yes Figure 1 The diagram shows a cross-sectional view of the motor, position detection component, and air guide shroud in the chainsaw.

[0040] Figure 6 yes Figure 5 A 3D view of the motor and magnetic components in the chainsaw shown.

[0041] Figure 7is Figure 5 is a plan view of the motor, mounting member, magnetic member, position sensor, and air deflector of the chain saw shown in FIG. 1;

[0042] Figure 8 is Figure 5 is an exploded view of the motor, mounting member, magnetic member, position sensor, and air deflector of the chain saw shown in FIG. 1;

[0043] Figure 9 is a perspective view of an electric power tool according to an embodiment of the present application;

[0044] Figure 10 is Figure 9 is an exploded view of the motor of the electric power tool shown in FIG. 2;

[0045] Figure 11 is Figure 10 is a plan view of the stator, rotor, and motor housing of the motor of the electric power tool shown in FIG. 2;

[0046] Figure 12 is Figure 10 is a sectional view of the rotor core, rotor magnet, and plastic member of the motor of the electric power tool shown in FIG. 2;

[0047] Figure 13 is Figure 10 is a sectional view of the motor housing, fan, and limit boss of the motor of the electric power tool shown in FIG. 2;

[0048] Figure 14 is Figure 10 is a plan view of the stator core and stator winding of the motor of the electric power tool shown in FIG. 2;

[0049] Figure 15 is Figure 10 is a plan view of the rotor, stator, support member, and output shaft of the motor of the electric power tool shown in FIG. 2;

[0050] Figure 16 is Figure 10 is a perspective view of the support member and bracket of the motor of the electric power tool shown in FIG. 2 according to an embodiment;

[0051] Figure 17 is Figure 16 is a sectional view of the base, tube member, support member, and stator core of the motor of the electric power tool shown in FIG. 2;

[0052] Figure 18 is Figure 10 is a perspective view of the bracket of the motor of the electric power tool shown in FIG. 2 according to another embodiment;

[0053] Figure 19 is Figure 18 is a sectional view of the base, tube member, and output shaft of the motor of the electric power tool shown in FIG. 2.

[0054] Figure notes: 100, chain saw; 100a, snow blower; 10, housing; 110, air guide / air guide cover; 111, groove; 112, opening; 20, output / functional part; 21, chain, 22, guide plate; 30, power supply device; 40, circuit board assembly; 51, oil pot; 200, motor; 210, stator; 220, rotor; 221, rotor core; 222, magnetic steel; 226, output shaft; 227, plastic part; 230, motor housing; 231, fan; 232, limiting boss; 240, position detection assembly; 241, magnetic part; 242, position sensor; 243, mounting part; 2431, mounting groove; 250, support part; 251, rim part; 252, spoke part; 260, bracket; 261, base; 2611, air inlet; 262, pipe part; 2621, air outlet. DETAILED DESCRIPTION

[0055] Before any embodiments of the application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the above-described drawings.

[0056] In this application, the terms "including", "containing", "having" or any other similar words are intended to cover a non-exclusive inclusion, so that a process, method, article or device including a series of elements does not only include those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such a process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0057] In this application, the term "and / or", is a description of the association relationship of the associated objects, which means that there can be three kinds of relationships. For example, A and / or B, can represent: A exists alone, A and B exist together, B exists alone, these three cases. In addition, the character " / " in this application generally represents that the front and rear associated objects are in a "and / or" relationship.

[0058] In this application, the terms "connection", "combination", "coupling", "mounting" can be direct connection, combination, coupling or mounting, or indirect connection, combination, coupling or mounting. Among them, for example, direct connection means that two parts or components are connected together without setting intermediate parts, indirect connection means that two parts or components are connected with at least one intermediate part, and the two parts or components are connected through the intermediate part. In addition, "connection" and "coupling" are not limited to physical or mechanical connection or coupling, and can include electrical connection or coupling.

[0059] In this application, those of ordinary skill in the art will understand that the relative terms used in connection with a quantity or a condition (for example, "about", "approximately", "substantially" and the like) include the stated value and have the meaning indicated by the context. For example, the relative terms at least include the degree of error associated with the measurement of a particular value, the tolerance caused by manufacturing, assembly, use, and the like associated with a particular value. Such terms should also be considered to disclose a range defined by the absolute values of the two endpoints. The relative terms can refer to a certain percentage (for example, 1%, 5%, 10% or more) of the indicated value plus or minus. The numerical value without the relative term should also be disclosed as a specific value with a tolerance. In addition, "substantially" when expressing the relative angular positional relationship (for example, substantially parallel, substantially perpendicular), can refer to a certain number of degrees (for example, 1 degree, 5 degrees, 10 degrees or more) plus or minus the indicated angle.

[0060] In this application, those of ordinary skill in the art will understand that the functions performed by the components can be performed by one component, multiple components, one part, or multiple parts. Similarly, the functions performed by the parts can also be performed by one part, one component, or multiple parts in combination.

[0061] In this application, the terms "upper", "lower", "left", "right", "front", "back" and the like are described in the orientation and positional relationship shown in the drawings, and should not be understood as limiting the embodiments of the application. In addition, it is also understood in the context that when referring to one element connected to another element "on" or "under", it can not only be directly connected to another element "on" or "under", but also indirectly connected to another element "on" or "under" through an intermediate element. It should also be understood that the terms "upper", "lower", "left", "right", "front", "back" and the like not only represent the positive direction, but also can be understood as the side direction. For example, the lower side can include the directly below, left below, right below, front below and back below, etc.

[0062] In this application, the terms "controller", "processor", "central processing unit", "CPU", "MCU" can be interchangeable. When a single unit "controller", "processor", "central processing unit", "CPU", or "MCU" is used to perform a specific function, unless otherwise specified, these functions can be performed by a single unit or multiple units.

[0063] In this application, the terms "device", "module" or "unit" can be realized in the form of hardware or software to achieve a specific function.

[0064] In this application, the terms "calculate", "determine", "control", "determine", "identify" and the like refer to the operations and processes of a computer system or similar electronic computing device (for example, controller, processor, etc.).

[0065] The technical solutions proposed in the application will be described in detail below in combination with specific embodiments and drawings.

[0066] Reference Figures 1 to 8 It shows a chain saw 100 as an embodiment in the application. Meanwhile, the figure also defines the front, back, left, right, up and down directions in the application. The chain saw 100 can include a tool body and a power supply device 30 for providing energy for the tool body. In some embodiments, the power supply device 30 can be a battery pack detachably connected with the tool body of the chain saw 100.

[0067] The tool body of the chain saw 100 includes a housing 10, a chain 21 and a guide plate 22. Among them, the housing 10 constitutes the main body of the chain saw 100, and a containing space is formed in the inside of the housing 10, which can support and contain the components to be described below. The chain 21 is a functional part 20 that actually implements cutting when the chain saw 100 works. The guide plate 22 supports and guides the chain 21, one end of which is supported on the housing 10, and the other end extends out of the housing 10 along the longitudinal direction of the housing 10, i.e. the front and back direction.

[0068] In addition to the housing 10, the chain 21 and the guide plate 22, the chain saw 100 also includes a motor 200 and a position detection assembly 240. Among them, the motor 200 is the prime mover of the chain saw 100, which can be arranged in the containing space formed by the housing 10, and it converts the electrical energy provided by the power supply device 30 into mechanical energy of its output shaft 226 rotation, and then directly or indirectly drives the chain 21 to implement cutting around the guide plate 22 through a transmission assembly. The motor 200 includes a stator 210 and a rotor 220 rotating relative to the stator 210, and the motor 200 used in the chain saw 100 in the application is a dynamo. The position detection assembly 240 is also used in the chain saw 100 to detect the position of the rotor 220 of the motor 200. Specifically, the chain saw 100 also includes a controller and a driving circuit, the controller can control the operation of the motor 200, it will receive the data related to the position of the rotor of the motor 200 measured by the position detection assembly 240, call the relevant control program and output the control signal to the driving circuit based on the above data, so that the driving circuit adjusts the driving signal and then changes the magnetic field of the stator 210, drives the rotor 220 and the output shaft 226 of the motor 200 to operate in the expected way.

[0069] In the application, as Figures 4 to 8As shown, the position detection assembly 240 of the chain saw 100 includes a magnetic piece 241 and a position sensor 242, and the position of the rotor 220 can be sensed by electromagnetic induction phenomenon between the magnetic piece 241 and the position sensor 242. The magnetic piece 241 is arranged on one end of the output shaft 226 of the motor 200, and the position sensor 242 is arranged on the air guide part 110 of the housing 10 for guiding the cooling air flow. Specifically, the magnetic piece 241 can be a magnet, and the position sensor 242 can be a magnetic encoder or a Hall sensor, which has a Hall element built-in. The position sensor 242 can sense the size and direction of the rotor 220 magnetic field by the Hall effect between the Hall element and the magnet, so as to obtain the current position of the rotor 220 of the motor 200. The air guide part 110 of the housing 10 in the chain saw 100 is generally adjacent to the motor 200. By arranging the magnetic piece 241 and the position sensor 242 at the above position, the original installation space in the chain saw 100 can be effectively utilized, and the relative position relationship required for the normal cooperation and work of the magnetic piece 241 and the position sensor 242 can be met. In addition, the position sensor 242 located on the air guide part 110 can also achieve effective heat dissipation, which can meet the design requirements of compact structure, high power and high chain speed of the chain saw 100.

[0070] In some embodiments, the magnetic piece 241 is fixed to the non-output end of the output shaft 226 of the motor 200, i.e., the end away from the guide plate 22 and the chain 21. An installation piece 243 for installing the magnetic piece 241 is arranged on the end, and the magnetic piece 241 is connected to the output shaft 226 of the motor 200 through the installation piece 243. In some embodiments, as shown in Figure 8 The installation piece 243 is sleeved on the non-output end of the output shaft 226 of the motor 200, and has an installation groove 2431 for embedding the magnetic piece 241. Specifically, the radial cross section of the installation piece 243 can be in the shape of "H". In some embodiments, the magnetic piece 241 can be in the shape of a disc.

[0071] In some embodiments, the chain saw 100 further includes a fan 231 installed on the output shaft 226 of the motor 200. The fan 231 is located between the magnetic piece 241 and the motor 200 in the axial direction of the output shaft 226, and the magnetic piece 241 is located between the air guide part 110 and / or the position sensor 242 and the fan 231. In other words, as shown in Figures 5 to 8 From the non-output end to the output end of the output shaft 226 of the motor 200, the air guide part 110 of the housing 10, the position sensor 242, the magnetic piece 241, the fan 231, and the stator 210 and the rotor 220 of the motor 200 are arranged in sequence.

[0072] In some embodiments, as shown in Figures 4 to 8As shown, the chain saw 100 housing 10 comprises a wind guide cover 110, and the wind guide 110 is located in the wind guide cover 110. In some embodiments, the chain saw 100 housing 10 comprises an outer housing and an inner housing, and the wind guide cover 110 belongs to the inner housing, which can support and accommodate the motor 200 and can cooperate with the air outlet on the outer housing to guide the heat dissipation airflow flowing through the motor 200 out of the housing 10. In other embodiments, the wind guide cover 110 can also belong to the outer housing, which has an air outlet for the heat dissipation airflow to blow out.

[0073] In some embodiments, as shown in Figure 5 , Figure 7 The wind guide cover 110 has a groove 111 away from the motor 200, and the position sensor 242 is arranged in the groove 111. Specifically, the groove 111 bottom can serve as a mounting surface for the position sensor 242 to be connected by screws or the like. In some embodiments, the groove 111 is also provided with an opening 112 for the circuit cable and the heat dissipation airflow to pass through, so that the data of the position sensor 242 can be output and better heat dissipation can be achieved.

[0074] In some embodiments, the motor 200 output shaft 226 is provided with the magnetic member 241, and at least one end of the magnetic member 241 extends into the groove 111, so that the position sensor 242 can accurately and effectively detect the rotor position of the motor 200 by sensing the magnetic member 241.

[0075] In some embodiments, as shown in Figure 4 , Figure 8 The projection of the magnetic member 241 and the position sensor 242 in the axial direction of the motor 200 output shaft 226 at least partially overlaps. In some embodiments, the position sensor 242 can be a magnetic encoder, and the number thereof can be one, which is located near the position facing the radial center of the motor 200. In other embodiments, the position sensor 242 can be a linear Hall sensor, and the number thereof can be two or three, which are arranged in the circumferential direction facing the motor 200 output shaft 226.

[0076] In some embodiments, the motor 200 and its output shaft 226 extend in the transverse direction of the housing 10, i.e. left and right direction, and the straight line where the output shaft 226 is located is substantially perpendicular to the plane where the guide plate 22 is located. In the foregoing, in some embodiments, the plane where the magnetic member 241 in the shape of a disc or the like is located is substantially parallel to the plane where the guide plate 22 is located. In some embodiments, the groove 111 groove body extends in the left and right direction. In some embodiments, the mounting surface of the groove bottom or the plane where the position sensor 242 is located or the plane where multiple position sensors 242 are located together can be substantially parallel to the plane where the guide plate 22 is located.

[0077] In some embodiments, as shown in Figure 2 , Figure 3As shown, the chain saw 100 further comprises a circuit board assembly 40 and an oil tank 51, and the orthographic projection of the motor 200 and the oil tank 51 in a plane perpendicular to the guide plate 22 substantially falls into the orthographic projection of the circuit board assembly 40 in the plane perpendicular to the guide plate 22, i.e., the projection of the motor 200 and the oil tank 51 in the up-down direction substantially falls into the projection of the circuit board assembly 40 in the up-down direction, so as to make full use of the inside of the chain saw 100 shell and reduce the combined space of the three. In some embodiments, the circuit board assembly 40 is located above the motor 200 and the oil tank 51. In some embodiments, the motor 200 and the oil tank 51 are arranged along the front-rear direction.

[0078] In addition, in the light of the foregoing, the chain saw 100 of the present application has the characteristics of compactness and high power, and in some embodiments, the output power of the chain saw 100 is greater than or equal to 1000W. Preferably, in some embodiments, the output power of the chain saw 100 is greater than or equal to 3000W. Preferably, in some embodiments, the output power of the chain saw 100 is greater than or equal to 5000W. The output power of the power tool can be calculated based on the average working current of the power tool and the power supply device 30 such as the battery pack. The average working current of the power tool generally varies within a numerical range, and the output power thereof can correspondingly vary within a numerical range. In some embodiments, the maximum output power of the chain saw 100 is greater than or equal to 5000W.

[0079] In some embodiments, the chain speed of the chain saw 100 is greater than or equal to 10m / s. Preferably, in some embodiments, the chain speed of the chain saw 100 is greater than or equal to 20m / s. Preferably, in some embodiments, the chain speed of the chain saw 100 is greater than or equal to 40m / s. The chain speed of the chain saw 100 can be the speed of the tooth portion of the chain 21 passing through the cutting object when the chain saw 100 is working.

[0080] In some embodiments, the power density of the motor 200 of the chain saw 100 is greater than or equal to 1000W / kg. Preferably, in some embodiments, the power density of the motor 200 of the chain saw 100 is greater than or equal to 2000W / kg. Preferably, in some embodiments, the power density of the motor 200 of the chain saw 100 is greater than or equal to 3000W / kg. The power density of the motor 200 can be the ratio between its rated power and the mass of its necessary components.

[0081] In some embodiments, the outer diameter of the motor 200 of the chain saw 100 is greater than or equal to 50mm. Preferably, in some embodiments, the outer diameter of the motor 200 of the chain saw 100 is greater than or equal to 70mm.

[0082] In the light of the foregoing, the motor 200 adopted by the chain saw 100 in the present application can also be applied in other categories of power tools, so as to make the power tools have better output and heat dissipation performance. Figure 1 、 Figure 9which shows a chain saw as one of several embodiments of the electric power tool in the present application. It can be understood that Figure 1 The chain saw 100 and Figure 9 The snow blower 100a shown does not constitute a specific limitation on the technical solutions of the electric power tool and its motor to be described later. The electric power tool described below includes not only handheld tools such as chain saws, circular saws, and drills, but also bench tools such as miter saws and table saws, and outdoor power equipment such as snow blowers and lawn mowers.

[0083] As shown in Figure 1 , Figure 9 The electric power tool includes a housing 10, an output portion 20, a motor 200, and a power supply device 30. As mentioned above, the housing 10 forms an accommodation space, and the motor 200 is accommodated in the accommodation space of the housing 10. The housing 10 also generally forms a coupling portion for the power supply device 30 such as a battery pack to be mounted to the electric power tool and to supply power to the electric power tool. The output portion 20 is driven by the motor 200 to perform a corresponding tool function such as cutting, grinding, fastening, etc. The output portion 20 includes a functional piece 20 that actually performs the above-mentioned function. For example, the functional piece 20 can be a saw blade, a chain, a drill bit, etc., which can be directly or indirectly driven by the output shaft 226 of the motor 200 through a transmission assembly.

[0084] Referring to Figures 10 to 19 , the motor 200, i.e., the electric machine, includes a stator 210 and a rotor 220 rotating around the stator 210, and the stator 210 and the rotor 220 are arranged in a nested manner. In the case of an external rotor motor, the stator 210 is on the inside in the radial direction, and the rotor 220 is at least partially arranged on the outside of the stator 210 and rotates relative to the stator 210. In the case of an internal rotor motor, the stator 210 is on the outside in the radial direction, and the rotor 220 is at least partially arranged on the inside of the stator 210 and rotates relative to the stator 210. In some embodiments, the electric machine is a brushless motor. In some embodiments, the electric machine is a permanent magnet synchronous motor. Hereinafter, an external rotor permanent magnet synchronous motor will be mainly described. The rotor 220 includes a rotor core 221 and a magnet 222 fixed to the rotor core 221, and the stator 210 includes a stator core 211 and a stator winding 212 wound on the stator core 211, and the above-mentioned rotor core 221 and magnet 222 of the rotor 220 are sleeved outside the above-mentioned stator core 211 and stator winding 212 of the stator 210.

[0085] In the motor 200 of the electric power tool in the present application, a support 250 in the form of a rim and spoke structure will be added, as shown in Figure 15As shown, the stator 210 is provided with the support 250 at its radial center, which includes a rim portion 251 and a spoke portion 252. The rim portion 251 constitutes the outer edge of the support 250, and the spoke portion 252 is connected to the rim portion 251 within the rim portion 251 and forms a through hole for the output shaft 226 to pass through. In some embodiments, the support 250 supports the stator 210 at its outer periphery, and the rim portion 251 supports the stator core 211. The spoke portion 252 includes a plurality of spokes extending radially inward from the rim portion 251, and the plurality of spokes do not intersect and form a through hole for the output shaft 226 to pass through at the radial center of the stator 210. In some embodiments, the rim portion 251 includes an inner rim and an outer rim. The outer rim supports the stator core 211, and the inner rim forms a through hole for the output shaft 226 to pass through. The plurality of spokes of the spoke portion 252 are connected between the inner rim and the outer rim. The support 250 has a rim and spoke structure, which leaves a large hollow space in the rotor 220 and the stator 210 of the motor 200. Compared with the common bearing support scheme, the support 250 has obvious improvement in heat dissipation performance, and can also reduce weight and cost.

[0086] In some embodiments, the support is made of metal or modified plastic. The metal or modified plastic used has the characteristics of light weight and good heat dissipation, so as to better achieve the improvement effect described above and be easy to process. In some embodiments, the support is made of aluminum. In other embodiments, the support is made of thermoplastic or thermosetting plastic.

[0087] In some embodiments, the motor 200 is an inductive motor, which detects the position of the rotor 220 using a position sensor, such as a magnetic encoder. The position sensor can be installed near the end of the output shaft 226 of the motor 200, for example, as shown above. Alternatively, the position sensor, such as a Hall sensor, can be installed near the teeth or slots of the stator core 211 of the stator 210 of the motor 200.

[0088] In some embodiments, the power density of the motor 200 is greater than or equal to 2000 W / kg. Preferably, in some embodiments, the power density of the motor 200 is greater than or equal to 3000 W / kg. The power density of the motor 200 can be the ratio of its rated power to the mass of its necessary components. In some embodiments, the rated power of the motor 200 is greater than or equal to 3000 W and less than or equal to 7000 W. In other embodiments, the no-load rotating speed of the motor 200 is greater than or equal to 10000 rpm and less than or equal to 17000 rpm. In yet other embodiments, the outer diameter of the motor 200 is greater than or equal to 50 mm. Preferably, in some embodiments, the outer diameter of the motor 200 is greater than or equal to 50 mm and less than or equal to 105 mm. Preferably, in some embodiments, the outer diameter of the motor 200 is greater than or equal to 80 mm and less than or equal to 95 mm.

[0089] In some embodiments, the motor 200 is an external rotor motor, and the ratio of the outer diameter D1 of the stator 210 to the outer diameter D2 of the rotor 220 is greater than or equal to 0.7 and less than 1. In some embodiments, the ratio of the outer diameter D1 of the stator 210 to the outer diameter D2 of the rotor 220 is greater than or equal to 0.8 and less than 1. Figure 11 Figure 12 In some embodiments, the outer diameter D1 of the stator 210 of the motor 200 can be the outer diameter of the stator core 211 of the motor 200, and the outer diameter D2 of the rotor 220 can be the outer diameter of the rotor core 221. Preferably, in some embodiments, the ratio of the outer diameter D1 of the stator 210 to the outer diameter D2 of the rotor 220 is greater than or equal to 0.8 and less than 1, so that the stator 210 and the rotor 220 are more compactly configured to form the motor 200, and the size of the motor 200 is reduced.

[0090] In some embodiments, the pole arc coefficient of the rotor 220 of the motor 200 is greater than or equal to 0.6 and less than 1. In some embodiments, the pole arc coefficient of the rotor 220 of the motor 200 is greater than or equal to 0.7 and less than 1. Figure 12 In some embodiments, the pole arc coefficient of the rotor 220 of the motor 200 is greater than or equal to 0.6 and less than 1. In some embodiments, the pole arc coefficient of the rotor 220 of the motor 200 is greater than or equal to 0.7 and less than 1.

[0091] In some embodiments, the magnetic steel 222 in the rotor 220 is fixed to the rotor core 221 in a plastic-wrapped manner. As shown in Figure 10 Figure 12 Figure 15 In some embodiments, the motor housing 230 is an aluminum part, which is hot-fitted with the rotor core 221. In some embodiments, the inner wall of the motor housing 230 is further formed with a limiting boss 232 for limiting the rotor core 221 in the axial direction, thereby enhancing the fixing effect of the motor housing 230 on the rotor core 221.

[0092] In some embodiments, the motor 200 further comprises a motor housing 230 and a fan 231 integrally formed with the motor housing 230, and the fan 231 is arranged on the output shaft 226 of the motor 200 and located on a plane perpendicular to the output shaft 226 of the motor 200. As shown in Figure 10 Figures 16 to 19 ​​​​As shown, the fan 231 is integrally formed with the motor housing 230, and is arranged on the output shaft 226 of the motor 200, which can be in interference fit with the motor housing 230 to ensure stable connection. From the non-output end to the output end of the motor 200, the motor housing 230 is sequentially provided with the fan 231, a limiting boss 232, a housing main body, and another limiting boss 232, and the rotor core 221 is supported and limited by the limiting boss 232 in the housing main body.

[0093] In some embodiments, the motor 200 further comprises a bracket 260, and the stator 210, the rotor 220, the output shaft 226, the support 250, and the bracket 260 are coaxially arranged, and the stator 210, the rotor 220, the output shaft 226, and the support 250 can be sleeved or penetrated on the bracket 260. In the present embodiment, the bracket 260 further forms or cooperates with the above components to form an air inlet 2611 and an air outlet 2621 through which cooling air flows. Specifically, as shown in Figure 16 The bracket 260 can include a base 261 and a pipe component 262, and the base 261 is connected or integrally formed with the pipe component 262. The plane on which the base 261 is located can be substantially perpendicular to the straight line on which the pipe component 262 is located. The base 261 is axially away from the fan 231, and the pipe component 262 can be sleeved or penetrated by the stator 210, the rotor 220, the output shaft 226, and the support 250. The bracket base 261 is provided with a radially or axially extending air inlet 2611, and the pipe component 262 can form an axially extending air outlet 2621 with the output shaft 226 or the support 250 penetrated therein. The cooling air will be blown into the air inlet 2611, taking away the heat on the surface of the stator 210 and / or the support 250 attached to the bracket 260, and then blown out of the air outlet 2621.

[0094] In some embodiments, the support 250 is connected or integrally formed with the bracket 260, as shown in Figure 17 , Figure 18 The support 250 in the form of a rim and spoke structure is arranged in the pipe component 262 of the bracket 260, the output shaft 226 is penetrated in the support 250, the stator 210 and the rotor 220 are sleeved outside the pipe component 262, and the bracket 260 cooperates with the support 250 to form an axially extending air flow channel to effectively cool the stator 210 attached to the outer periphery of the bracket 260 and the support 250 in the air flow channel. In other embodiments, as shown in Figure 19 , Figure 14As shown, the air inlet 2611 extends radially in the base 261, the tube component 262 cooperates with the output shaft 226 inside which the tube component 262 is arranged to form an air flow channel, and the air outlet 2621 extends axially between the tube component 262 and the output shaft 226. The stator 210, the rotor 220, and the support 250 can be arranged outside the tube component 262 of the bracket 260. In some other embodiments, the projection of the support 250 and the bracket 260 in the axial direction of the motor 200 can partially overlap, and / or the projection of the support 250 and the bracket 260 in the radial direction of the motor 200 can partially overlap or not overlap.

[0095] In some embodiments, the stator core 211 is provided with a plurality of radially extending teeth in the circumferential direction, and the stator winding 212 is wound on the teeth. In addition, the teeth of the stator core 211 have the feature of being of unequal width in the radial direction. For example, Figure 14 As shown, the width W of the tooth of the stator core 211 is the width of the tooth in the direction perpendicular to the extending direction of the tooth. In some embodiments, the teeth of unequal width in the radial direction have a ratio of the maximum value of the width to the minimum value of the width greater than 1 and less than or equal to 1.8. For example, ​ As shown, the maximum value of the width of the tooth of the stator core 211 of the motor 200 is located at the tooth top, i.e., W1, and the minimum value of the width of the tooth is located at the tooth bottom, i.e., W2, and the ratio of the two is in the range of 1 to 1.8. In addition, the tooth top is the end of the tooth away from the yoke of the core, and the tooth bottom is the end of the tooth close to the yoke of the core. Preferably, in some embodiments, the ratio of the maximum value of the width of the tooth to the minimum value of the width is greater than 1 and less than or equal to 1.5.

[0096] In some embodiments, the stator windings 212 wound on different teeth of the stator core 211 are in-phase or out-of-phase relationship. For example, in a three-phase motor, a plurality of windings wound on a plurality of teeth can belong to the A phase of the motor, and a plurality of windings wound on another plurality of teeth can belong to the B phase of the motor. The specific winding sequence and connection relationship can be variable. In the present embodiment, the number of turns of two stator windings 212 belonging to the same phase can be different. The number of turns of the stator winding 212 is the number of wires wound on the tooth. In some embodiments, the motor 200 is a 10-pole 12-slot motor, the number of rotor magnetic steels 222 is 10, and the stator core 211 has 12 teeth. It can be understood that in other embodiments, the number of rotor magnetic steels 222 and the number of stator 210 teeth can also be adjusted according to actual scenarios.

[0097] The numerical settings of the above-mentioned parameters such as the outer diameter ratio of the stator and rotor 210, 220, the pole arc coefficient of the rotor 220, the tooth width of the stator core 211, and the number of turns of the stator winding 212 are aimed at ensuring that the high-power motor 200 operates accurately and efficiently. According to simulation and experiments, the relevant parameters can achieve the effects of improving the slot fill rate, reducing the harmonic distortion rate, stabilizing the torque fluctuation, and reducing the motor noise.

[0098] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the above embodiments do not limit the present application in any form, and any technical solutions obtained by equivalent replacement or equivalent transformation fall within the protection scope of the present application.

Claims

1. An electric tool, comprising: A motor for providing power to the power tool, comprising a stator and a rotor rotating relative to the stator; The power supply device is at least electrically connected to the motor; The output section is driven by the motor; The stator is characterized by having a support member comprising a rim portion and a spoke portion at its radial center.

2. The power tool according to claim 1, characterized in that, The rotor is sleeved outside the stator, and the support member is disposed inside the stator and supports the stator.

3. The power tool according to claim 1, characterized in that, The ratio of the outer diameter of the stator to that of the rotor is greater than or equal to 0.

7.

4. The power tool according to claim 1, characterized in that, The polar arc coefficient of the rotor is greater than or equal to 0.6 and less than 1.

5. The power tool according to claim 1, characterized in that, The power density of the motor is greater than or equal to 2000W / kg.

6. The power tool according to claim 1, characterized in that, The stator includes a stator core and a stator winding. The stator core has a plurality of radially extending teeth, and the stator winding is wound around the teeth. The teeth are of unequal width in the radial direction, wherein the width of the teeth is the width of the teeth in the direction perpendicular to their extension.

7. The power tool according to claim 6, characterized in that, The ratio of the maximum to the minimum width of the tooth is greater than 1 and less than or equal to 1.

8.

8. The power tool according to claim 1, characterized in that, The rotor includes a rotor core and a magnet. The magnet is fixed to the rotor core by plastic coating. The inner wall of the motor housing has a limiting boss that limits the rotor core in the axial direction.

9. The power tool according to claim 1, characterized in that, The power tool also includes a bracket, the stator and the rotor are sleeved on the bracket, the support member is coaxially arranged with the bracket, and the bracket has an air inlet and an air outlet for heat dissipation airflow to pass through.

10. The power tool according to claim 1, characterized in that, The power tool also includes a fan, and the motor has a motor housing that is integrally formed with the fan.

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