power tools

Abstract

This utility model relates to an electric tool, comprising: a first housing, a receiving cavity enclosed by the first housing, and a motor assembly received in the receiving cavity. The motor assembly includes a drive shaft extending axially, a second housing sleeved on the drive shaft, and a plurality of magnets located on the inner wall of the second housing. The electric tool includes a first fan rotating with the drive shaft. The first fan is located inside the second housing and includes a plurality of fan blades, a support portion connecting the plurality of fan blades, and a plurality of magnetic shielding portions extending from the support portion. Each magnet is located between two adjacent magnetic shielding portions in a circumferential direction perpendicular to the axial direction. The first fan of this utility model is located inside the second housing, and the fan blades are integrally formed with the support portion and the magnetic shielding portions, which is beneficial for improving the heat dissipation efficiency of the motor assembly, reducing the number of parts inside the working assembly, and simplifying the assembly process.

Description

Technical Field

[0001] This utility model relates to an electric tool, and more particularly to an electric tool with fewer motor parts and better heat dissipation. Background Technology

[0002] Currently, the motors of front-mounted power tools on the market are located inside the working head. When mowing, dust and grass clippings fly around, which puts higher demands on the heat dissipation of the core power component - the motor. In addition, the motor assembly has many internal parts and is complicated to assemble, making it inconvenient for users to operate and resulting in a poor user experience.

[0003] In view of the above problems, it is indeed necessary to provide a power tool to overcome the shortcomings of the prior art. Utility Model Content

[0004] In view of the shortcomings of the prior art, the purpose of this utility model is to provide an electric tool that can effectively improve the heat dissipation of the motor and reduce the number of parts in the motor assembly, thus simplifying the assembly process.

[0005] The present invention solves the existing technical problems by adopting the following technical solution: an electric tool, comprising: a first housing, a receiving cavity enclosed by the first housing, and a motor assembly received in the receiving cavity, the motor assembly comprising a drive shaft extending axially, a second housing sleeved on the drive shaft, and a plurality of magnets located on the inner wall of the second housing; the electric tool comprising a first fan rotating with the drive shaft, the first fan being located inside the second housing and comprising fan blades, a support portion connecting the plurality of fan blades, and a plurality of magnetically shielding portions extending from the support portion, each of the magnets being located between two adjacent magnetically shielding portions in a circumferential direction perpendicular to the axial direction.

[0006] A further improvement is that several of the magnetic shielding parts are spaced apart in the circumferential direction and are attached to the inner sidewall of the second housing.

[0007] A further improvement is that the magnetic shielding part extends from the support part toward the side away from the fan blade, and the fan blade, the support part, and the magnetic shielding part are integrally formed.

[0008] A further improvement is as follows: the support part is connected to the radial outer periphery of the fan blade and forms a ring-shaped structure, and the outer peripheral wall of the support part is fitted to the inner side wall of the second housing.

[0009] A further improvement is that each magnet abuts against the bottom side of the support in the axial direction and against the magnetically shielding part in the circumferential direction.

[0010] A further improvement is as follows: the second housing includes a fixed post connected to the drive shaft, and the first fan includes a mounting part sleeved on the fixed post and a plurality of fan blades arranged circumferentially along the mounting part, with one end of the plurality of fan blades connected to the mounting part and the other end connected to the support part.

[0011] A further improvement is that the magnetic shielding part, the support part, the mounting part, and the fan blade are formed into an integrated structure.

[0012] A further improvement is as follows: the motor assembly includes a stator support and a coil winding connected to the stator support; the magnetic shielding part and the magnet are spaced apart in the circumferential direction to surround the outer periphery of the coil winding; and there is a gap between the coil winding and the magnetic shielding part.

[0013] A further improvement is as follows: the stator support includes a base, a baffle integrally formed with the base, and an air outlet formed by the base and the baffle. The baffle extends into the interior of the second housing, and the air outlet is in fluid communication with the gap.

[0014] A further improvement is as follows: the first housing includes a first air inlet communicating with the outside, the second housing includes a second air inlet communicating with the first air inlet, and the fan blade, magnet and magnetic shielding part are located axially between the second air inlet and the air outlet.

[0015] Compared with the prior art, the present invention has the following advantages: The first fan of the present invention is located in the second housing and includes several fan blades and several magnetic shielding parts integral with the fan blades. On the one hand, it is beneficial to improve the heat dissipation efficiency of the motor assembly. On the other hand, it is beneficial to reduce the number of parts of the whole machine and simplify the assembly process. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the power tool of this utility model;

[0017] Figure 2 yes Figure 1 A cross-sectional view of the working components of the power tool shown;

[0018] Figure 3 yes Figure 1 A cross-sectional view of the working components of the power tool shown from another angle;

[0019] Figure 4 yes Figure 1 The diagram shows a partial disassembly of the working components of the power tool.

[0020] Figure 5 yes Figure 4 The diagram shows the structure of the motor assembly.

[0021] Figure 6 yes Figure 5 A cross-sectional view of the motor assembly shown;

[0022] Figure 7 yes Figure 4 The diagram shows the structure of the first fan.

[0023] Figure 8 yes Figure 5 A cross-sectional view of the stator support of the motor assembly shown;

[0024] Figure 9 yes Figure 8 The top view of the stator support shown;

[0025] Figure 10 yes Figure 4 A schematic diagram of the structure of the second fan.

[0026] Meaning of the reference numerals in the diagram:

[0027] 100 power tools, 10 working components Execution component 11 Cut-off component 12 Connection component 20; Handle component 30 Main controller 31, Auxiliary controller 32 Adjustment button 33 Power supply component 40 Battery pack mounting section 41 First housing 101 Receiving cavity 102 Connecting part 103 First air inlet 104, guide section 105 Motor assembly 13 Drive shaft 131 Second housing 132 Stator support / base 133 Baffle 134 Magnet 135 Second air inlet 136, air inlet side 137 Air outlet side 138, air outlet 139 First Fan 14 Installation Unit 141 Fan blade 142 Support part 143 Magnetic shielding part 144 Second fan 15 Air guide section 151 Extension section 152 Part 153 Centrifugal fan blade 154

[0028] Shaft lock part 155 First bearing 16

[0029] Second bearing 17 Detailed Implementation

[0030] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. In the following description, reference is made to the accompanying drawings, which illustrate several embodiments of the invention. It should be understood that other embodiments may also be used, and changes in mechanical composition, structure, electrical, and operation may be made without departing from the spirit and scope of the invention. Although the terms first, second, etc., are used herein to describe various elements in some embodiments, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. Furthermore, as used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context indicates otherwise. For example, terms indicating orientation or positional relationship, such as “upper,” “lower,” “front,” and “rear,” are based solely on the orientation or positional relationship shown in the drawings and are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device / element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0031] Please see Figure 1 The diagram shows the structure of the power tool 100 of this utility model. The power tool 100 of this utility model includes a working component 10, a handle assembly 30 disposed opposite to the working component, and a connecting component 20 for connecting the working component and the handle assembly. The handle assembly 20 includes a main handle 31 away from the working component and an auxiliary handle 32 close to the working component. The main handle is provided with a control component for user operation, and the control component includes an adjustment button 33 for user operation.

[0032] The rear end of the main handle 31 of the power tool 100 also includes a power supply component 40 for providing power to the working component 10. The power supply component 40 includes two battery packs (not shown) connected in series and a battery pack mounting part 41 for vertically placing the battery packs. The two battery packs are vertically inserted into both sides of the battery pack mounting part 41, which is conducive to miniaturizing the power supply component 40 of the power tool 100.

[0033] The power tool also includes an execution component 11 located below the working component 10 and a cutting component 12 for operation. In this embodiment, the power tool 100 is a lawnmower, the execution component 11 is a trimmer head and the cutting component 12 is a trimmer rope; in other embodiments, the power tool may be a brush cutter, in which case the execution component is a cutting blade.

[0034] Please see Figures 2 to 3As shown, this utility model provides an electric tool, which may be a lawnmower, brush cutter, etc. The working component 10 is located at the front end of the lawnmower 100. The working component 10 includes a first housing 101, a receiving cavity 102 surrounded by the first housing 101, a motor assembly 13 housed in the receiving cavity 102, and a fan assembly driven by the motor assembly 13 to generate cooling airflow.

[0035] In this embodiment, the first housing 101 of the lawnmower 100 is a split design, which includes an upper housing and a lower housing. The two are fixedly connected by screws to form the receiving cavity 102. The upper housing is configured as a cover plate and the lower housing is configured as an upwardly open cylinder. The lower housing has a connecting part 103 extending outward from its outer peripheral wall. The connecting part 103 is used to connect with the connecting assembly 20.

[0036] The motor assembly 13 includes a drive shaft 131 extending axially, a second housing 132 sleeved on the drive shaft 131, and a stator bracket 133 connected to the first housing 101. The motor assembly 13 also includes stator windings sleeved on the stator bracket 133. In this embodiment, the drive motor located in the working assembly 10 at the front end of the lawnmower 100 is an external rotor motor, and the second housing 132 is the rotor housing sleeved on the drive shaft 131.

[0037] When assembling the front working component 10 of the lawnmower 100, the user first separates the upper and lower housings that are fixed by screws, then places the stator bracket 133 from the open end of the lower housing into the receiving cavity 102, and fixes the stator bracket 133 to the bottom of the lower housing by driving downward screws.

[0038] In this embodiment, the stator support 133 is directly fixed to the bottom of the lower housing. The connection between the stator support 133 and the first housing 101 can refer to either a direct or indirect connection. In other embodiments, a reduction gear may be provided below the motor assembly 13. In this case, the stator support 133 is directly fixed to the reduction gear, and the reduction gear is fixed to the first housing 101 by screws. Therefore, the stator support 133 is indirectly fixed to the first housing 101. Even in this indirect case, the stator support 133 is still within the scope of protection of this invention.

[0039] The working assembly 10 includes a baffle 134 located between the stator support 133 and the second housing 132. The baffle 134 extends at least partially axially into the second housing 132, and in a radial direction perpendicular to the axial direction, the baffle 134 partially overlaps with the second housing 132. The baffle 134 is configured as a ring of stiffeners extending from the stator support 133 toward the top of the second housing 132, and the baffle 134 is circumferentially disposed on the stator support 133.

[0040] When the lawnmower 100 performs lawnmowing operations, the motor assembly 13 in the working component 10 at its front end operates at high speed. The heat dissipation efficiency of the motor assembly 13 is low. Therefore, in order to improve the heat dissipation efficiency of the motor assembly 13, the present invention optimizes the structure of the heat dissipation air path of the motor assembly 13.

[0041] Regarding the stator support 133 of the motor assembly 13, the present invention provides a baffle 134 extending axially into the second housing 132 on the outer ring of the stator support 133. The baffle may be connected to the stator support 133 or may be integrally formed with the stator support 133.

[0042] Since the stator support 133 is a fixed component and the second housing 132, i.e. the rotor housing, is a movable component, the stator support 133 and the second housing 132 are spaced apart axially in the structure design to prevent interference between the two when the motor assembly 13 is in place, which would affect the normal operation of the motor assembly.

[0043] In this embodiment, the baffle 134 extends axially into the second housing 132, and the distance between the baffle 134 and the inner wall of the second housing 132 is small, so that most of the cooling airflow flows through the interior of the baffle 134. The baffle at least partially fills the gap between the stator support 133 and the second housing 132, which is used to prevent the cooling airflow entering the motor assembly 13 from flowing from the gap between the stator support 133 and the second housing 132 to the outer periphery of the stator support 133, thereby reducing the loss of cooling airflow and improving the heat dissipation efficiency of the motor assembly 13.

[0044] In this embodiment, the baffle 134 partially overlaps with the second housing 132 in the radial direction, and the distance between the baffle 134 and the inner wall of the second housing 132 in the radial direction perpendicular to the axial direction is 0.2-2mm. This distance is designed to be as small as possible so that when the cooling airflow flows from top to bottom through the inside of the motor assembly, most of it enters the interior of the baffle 134, thereby reducing the airflow loss from the gap between the baffle 134 and the second housing 132.

[0045] The stator support 133 includes a base, which is axially spaced from the second housing 1332 to prevent interference between the stator support 133 and the second housing 132 during the operation of the motor assembly 13, thereby affecting the normal operation of the motor. The base is configured as a ring of ribs extending axially from the bottom of the stator support 133, and the base is circumferentially disposed on the outer periphery of the stator support 133.

[0046] The baffle 134 is integrally formed with the base and extends axially from the base. The radial dimension of the baffle 134 is smaller than that of the base. The baffle 134 extends axially from the base toward the second housing 132 to cover the gap in the radial direction to prevent the cooling airflow flowing through the motor assembly 13 from flowing out of the gap and causing the loss of cooling airflow.

[0047] Please see Figure 4 As shown, the lawnmower 100 includes a fan assembly, which includes a first fan 14 for generating the cooling airflow and a second fan 15 located at least partially outside the first housing 101 for discharging the cooling airflow from the first housing 101. The first housing 101 includes a connecting portion 103 extending outward from its outer peripheral wall and a first air inlet 104 communicating with the receiving cavity 102. The first air inlet 104 communicates with the outside and is located at the connection between the connecting portion 103 and the first housing 101, for allowing the cooling airflow to enter the receiving cavity 102.

[0048] The second housing 132 has a second air inlet 136 at one end away from the stator support 133, which allows the cooling airflow to enter. The second air inlet 136 communicates with the first air inlet 104. The outer wall of the second housing 132, the base, the baffle 134, and the inner wall of the first housing 101 together form an airflow path between the first air inlet 104 and the second air inlet 136.

[0049] The cooling airflow enters the receiving cavity 102 enclosed by the first housing 101 from the first air inlet 104, then flows upward through the space defined by the base, baffle 134, outer wall of the second housing 132, and inner wall of the first housing 101 to the top of the second housing 132, and enters the interior of the motor assembly 13 from the second air inlet 136 of the second housing 132, thereby dissipating heat from the motor assembly 13. The baffle 134 extending axially from the stator support 133 prevents the cooling airflow entering the receiving cavity 102 from the first air inlet 104 from being directly sucked away by the second fan 15 through the gap between the stator support 133 and the second housing 132 before being discharged from the first housing 101, thus reducing cooling airflow loss.

[0050] The connecting assembly 20 of the lawnmower 100 forms a hollow channel. Several through holes (not shown) are provided below the connecting assembly 20 near the working assembly 13, communicating with the first air inlet 104. These through holes connect the hollow channel, the first air inlet 104, and the receiving cavity 102. By providing several through holes below the connecting assembly 20, the air intake volume is increased, thereby improving the cooling efficiency of the motor assembly.

[0051] The cooling airflow enters the hollow channel of the connecting component 20 through several through holes located below the connecting component 20, flows to the first air inlet 104 formed at the connecting part 103, the first air inlet 104 is connected to the receiving cavity 102 that houses the motor assembly 13, the cooling airflow enters the receiving cavity 102 from the first air inlet 104, and flows into the interior of the motor assembly 13 from the second air inlet 136 under the action of the first fan 14, thereby forming an airflow channel for cooling the motor assembly 13 in the second housing 132.

[0052] In this embodiment, the first fan 14 is an axial fan. The first fan 14 rotates with the drive shaft 131. The first fan 14 is located inside the second housing 132 and includes fan blades 142 and several magnetic shielding parts 144 integrally formed with the fan blades 142.

[0053] The fan blades 142 are designed to draw air from top to bottom when the motor assembly 13 rotates. The cooling airflow flows from the first air inlet 104 to the top of the motor assembly 13 under the negative pressure of the axial fan, and then enters the motor assembly 13 to cool it. In addition, the second fan 15 is a centrifugal fan. The cooling airflow flowing through the motor assembly 13 is orderly discharged from the first housing 101 under the action of the centrifugal fan, thereby improving the cooling efficiency of the motor assembly 13.

[0054] Please see Figures 5 to 6 As shown, the motor assembly 13 includes a stator support 133 and a coil winding connected to the stator support 133. The motor assembly 13 also includes a drive shaft 131 extending axially and at least partially located outside the first housing 101, and a second housing 132 rotating with the drive shaft 131, the second housing 132 being sleeved on the drive shaft 131.

[0055] The motor assembly 13 further includes a plurality of magnets 135 connected to the second housing 132. The magnets 135 are located on the inner wall of the second housing 132, and are correspondingly arranged with respect to the coil windings. The magnets 135 are adhered to the inner wall of the second housing 132 by adhesive, and are spaced apart on the inner side of the second housing 132. Each magnet 135 is located between two adjacent magnetic isolation portions 144 in the circumferential direction perpendicular to the axial direction. The magnetic isolation portions 144 and the magnets 135 are spaced apart in the circumferential direction to surround the outer periphery of the coil windings, and a gap exists between the coil windings and the magnetic isolation portions 144.

[0056] The baffle 134 is located axially on the bottom side of the magnet 135 and is nearly flush with the bottom side of the magnet 135. The radial distance between the magnet 135 and the drive shaft 132 is less than or equal to the radial distance between the baffle 134 and the drive shaft 131. This allows the cooling airflow to enter the motor assembly 13 from the second air inlet 136 at the top of the second housing 132, and after passing the inside of the magnet 135, it can be directly guided into the interior of the baffle 134, reducing airflow loss from the gap between the baffle 134 and the second housing 132.

[0057] The drive shaft 131 of the motor assembly 13 is provided with bearing support at both the upper and lower ends. The drive shaft 131 is provided with a first bearing 16 at the end near the first fan 14. The first bearing 16 is located outside the second housing 132 and near the upper housing of the first housing 101. The first bearing 16 abuts against the top wall of the first housing 101 to support the drive shaft 131.

[0058] A second bearing 17 is provided at one end of the drive shaft 131 near the second fan 15. The second bearing 17 is located between the stator bracket 133 and the second fan 15 to support the drive shaft 131. The second bearing 17 abuts against the mating part 153 of the second fan 15. The mating part 153 is used to cooperate with the drive shaft 131 and rotate together with the drive shaft 131. The interior of the mating part 153 is provided with a square keyway to cooperate with the flat square on the drive shaft 131. The second fan 15 rotates together with the drive shaft 131 through the mating part 153, which helps to improve the heat dissipation efficiency of the motor assembly 13.

[0059] Please see Figure 7As shown, the fan assembly includes a first fan 14 located within the second housing 132. The second housing 132 includes a fixing post connected to the drive shaft 131. The first fan 14 includes a mounting portion 141 sleeved on the fixing post and a plurality of fan blades 142 arranged circumferentially along the mounting portion 141. One end of each fan blade 142 is connected to the mounting portion 141, and the other end is connected to the support portion 143. Pressing the first fan 14 into the second housing 132 simplifies the installation process inside the motor assembly 13, facilitates user disassembly and assembly of the motor assembly 13, and improves user convenience.

[0060] The first fan 14 includes several fan blades 142, a support portion 143 connecting the fan blades, and several magnetic shielding portions 144 extending from the outer wall of the support portion 143 toward the baffle 134. The fan blades 142, support portion 143, magnetic shielding portions 144, and mounting portion 141 form an integral structure. The fan blades 142, magnet 135, and magnetic shielding portions 144 are axially located between the second air inlet and the air outlet 139. The support portion 143 and the magnetic shielding portions 144 together form a magnet bracket. In this embodiment, the magnet bracket and the first fan 14 that generates cooling airflow are an integral structure, which helps to reduce the design and installation steps of the magnet bracket, thereby saving manufacturing costs and simplifying the assembly process.

[0061] The support portion 143 is connected to the radial outer periphery of the fan blade 142 and is configured as a ring structure. The outer peripheral wall of the support portion 143 is disposed in close contact with the inner sidewall of the second housing 132. The support portion 143 is configured as a ring of ribs surrounding the outer periphery of the fan blade 142. One end of the fan blade 142 is connected to the mounting portion 141 and the fan blade 142 is circumferentially distributed on the outer periphery of the mounting portion 141. The other end of the fan blade 142 is connected to the support portion 143. The support portion 143 surrounds the outer periphery of the fan blade 142, that is, the fan blade 142 is circumferentially distributed on the inner wall of the support portion 143.

[0062] The magnetic shielding part 144 is spaced apart in the circumferential direction of the support part 143. The magnetic shielding part 144 extends from the support part 143 toward the side away from the fan blade 142. The magnetic shielding part 144 is configured as a plurality of extended ribs spaced apart on the outer peripheral wall of the support part 143. There is a certain distance between the bottom end of the magnetic shielding part 144 and the top end of the baffle 134. The magnetic shielding part 144 and the support part 143 constitute a magnetic steel bracket and are attached to the inner wall of the second housing 132. Therefore, the magnetic shielding part 144 is attached to the inner side wall of the second housing 132.

[0063] When the cooling airflow enters the second housing 132 under the action of the first fan 14, since the magnetic shielding part 144 is attached to the inner wall of the second housing 132, the cooling airflow flows from top to bottom along the inner wall of the magnetic shielding part 144. Therefore, the cooling airflow will not flow away from other gaps and cause airflow loss during the process of flowing inside the motor assembly 13.

[0064] Each of the magnetically shielding portions 144 is located circumferentially between two adjacent magnets 135, meaning that each magnet 135 is located circumferentially between two adjacent magnetically shielding portions 144. Each magnet 135 abuts against the bottom side of the support portion 143 axially and against the magnetically shielding portion 144 circumferentially. The magnets 135 abut against the magnetically shielding portions 144 on both sides circumferentially to prevent the plurality of magnets 135 from moving toward the top of the second housing 101 during rotation of the motor assembly 13; that is, the support portion 143 serves to support the magnets 135.

[0065] The support 143, the magnetic shielding 144, the magnet 135, and the baffle 134 together define an airflow channel for the cooling airflow, and the radial dimension of the baffle 134 is greater than or equal to the radial dimension of the fan blade.

[0066] When the cooling airflow enters the receiving cavity 102 from the first air inlet 104, under the negative pressure of the first fan 14, the cooling airflow is drawn to the top of the second housing 132 and enters the interior of the second housing 132 from top to bottom to cool the motor assembly 13. In order to reduce the loss of cooling airflow, the present invention follows the path of cooling airflow from top to bottom and tries not to hit the internal parts, that is, the inner diameter of the lower part is greater than or equal to the inner diameter of the upper part.

[0067] After the cooling airflow enters the interior of the second housing 132, the cooling airflow is guided downward by the support part 143 because the support part 143 is attached to the inner wall of the second housing 132. Since the magnetic shielding part 144 extends downward from the support part 143, the cooling airflow continues to flow downward along the magnetic shielding part 144. Since the magnet 135 is located between the two magnetic shielding parts 144, and the two side walls of the magnet 135 are in contact with the magnetic shielding parts 144, there is no gap between them for the cooling airflow to flow out, so the cooling airflow continues to flow downward.

[0068] The inner diameter of the baffle 134 around the stator support 133 is designed to be greater than or equal to the inner diameter of the magnet 135. The radial dimension of the baffle 134 is also greater than or equal to the radial dimension of the fan blade 142 of the first fan 14. This ensures that the cooling airflow will not encounter the baffle 134 and be lost during its downward flow. Furthermore, most of the cooling airflow flows from the inside of the baffle 134 and will not flow out of the outer periphery of the stator support 133 through the gap between the baffle 134 and the second housing 132, which also reduces the loss of cooling airflow.

[0069] After the cooling airflow enters the interior of the baffle 134, it flows out from the air outlet 139 at the bottom of the stator bracket 133. As the cooling airflow flows from top to bottom inside the second housing 132, the inner diameter of the internal parts gradually increases, so that the cooling airflow can smoothly flow out of the motor assembly 13 within the cooling airflow channel defined by the support 143, the magnetic shielding part 144, the magnet 135 and the baffle 134, and the loss is minimized so that most of the cooling airflow can effectively cool the motor assembly 13, thereby improving the heat dissipation effect of the motor assembly 13.

[0070] Please see Figures 8 to 9 As shown, the stator bracket 133 includes a through hole through which the drive shaft 131 passes. The through hole penetrates the stator bracket 133, and the stator bracket 133 includes a support column for mounting the stator winding of the motor. The support column extends toward the top of the second housing 132. The support column is located in the middle of the stator bracket 133, and the axial height of the support column is less than the axial height of the stator winding. The top end of the stator winding abuts against a fixing post on the second housing 132. The first fan 14 is mounted on the fixing post of the second housing 132. The first fan 14 is press-fitted between the second housing 132 and the stator winding to simplify the installation process of the motor assembly 13 and facilitate user operation.

[0071] The stator support 133 further includes a baffle 134 extending toward the first fan 14 and located within the second housing 132. The baffle 134 is arranged circumferentially along the stator support 133. The baffle 134 may extend upward from the stator support 133, i.e., the baffle 134 and the stator support 133 are an integral structure. The baffle 134 may also be a part fixed to the stator support 133 and extending upward. The baffle 134 is located between the stator support 133 and the second housing 132 to prevent cooling airflow from flowing out through the gap between them. In addition, as mentioned above, the radial dimension of the baffle 134 is greater than or equal to the radial dimension of the fan blade 142 of the first fan 14, so that the cooling airflow can fall into the interior of the baffle 134 with almost no loss and flow out from the bottom of the stator support 133, avoiding cooling airflow loss.

[0072] The stator support 133 includes an air inlet side 137 formed by the baffle 134 for the cooling airflow to enter, and an air outlet side 138 located at the bottom of the stator support 133 for the cooling airflow to exit. The bottom of the stator support 133 also includes several air outlets 139, which are formed by the base and the baffle 134.

[0073] The air outlet 139 is configured as an oblong air outlet, the baffle 134 extends into the interior of the second housing 132, and the air outlet 139 is in fluid communication with the gap between the coiled winding and the magnetic shielding part 144. The present invention designs the diameter of the air outlet 139 to be relatively large so that most of the cooling airflow flows out from the bottom of the motor assembly 13.

[0074] The air outlet 139 is configured as a hollow portion between the base of the stator bracket 133 and the support column. The stator bracket 133 also includes a boss located in the middle. The support column extends upward from the boss, and a plurality of air outlets 139 are formed between the boss and the base of the stator bracket 133.

[0075] The base of the stator bracket 133 is designed to be larger in the radial direction than the baffle 134, thereby increasing the diameter of the air outlet 139, which helps to increase the airflow channel of the cooling airflow and thus improve the cooling efficiency of the motor assembly 13.

[0076] The top of the second housing 132 includes several second air inlets 136 for the flow of cooling air. Each second air inlet 136 is a waist-shaped ventilation hole. These waist-shaped ventilation holes are spaced apart around the drive shaft 131 in the circumferential direction of the second housing 132, facilitating the flow of cooling air into the motor assembly 13 for cooling. The second air inlets 136 correspond to the locations of the stator bracket's air outlets 139 to allow for airflow. Specifically, the second air inlets 136 consist of three waist-shaped ventilation holes, and the air outlets 139 consist of four waist-shaped ventilation holes. In other embodiments, the number of ventilation holes can be two, four, or more. This invention does not limit the number of ventilation holes; the purpose of these ventilation holes is to facilitate the flow of cooling air within the second housing for effective cooling of the motor.

[0077] The side of the stator support 133 with a baffle 134 is the air inlet side 137. The baffle 134 can prevent the cooling airflow from flowing out of the stator support 133 through the gap between the stator support 133 and the second housing 132, so that most of the cooling airflow falls into the air inlet side 137 and flows out from the air outlet side 138. Similarly, the present invention follows the principle of minimizing the loss of cooling airflow, and designs the radial dimension of the air outlet side 138 to be greater than or equal to the radial dimension of the air inlet side 137, so that the cooling airflow will not hit the internal parts when flowing from top to bottom, thus avoiding the loss of cooling airflow, and effectively utilizing the cooling airflow to dissipate heat from the motor assembly 13.

[0078] Please see Figures 2 to 3 As shown, the second housing 132 encloses a downwardly open chamber. A fixing post is provided in the middle of the second housing 132 for assembly with the mounting portion 141 of the first fan 14, thereby forming the first fan 14 within the second housing 132. Unlike other embodiments where the first fan 14, i.e., the axial fan, is located outside the second housing 132, i.e., the rotor housing, the present invention designs the first fan 14 to be press-fitted into the second housing 132, which simplifies the assembly process and reduces production costs.

[0079] The second housing 132 and the stator support 13 are spaced apart in the axial direction to prevent interference between the second housing 132, which is a movable part, and the stator support 133, which is a fixed part, during rotation. Therefore, in order to fill the gap formed in the axial direction between the stator support 133 and the second housing 132, the stator support 133 includes a base that at least partially covers the chamber, and the baffle 134 extends from the base of the stator support 133 toward the first fan 14 to prevent the cooling airflow from flowing out of the gap.

[0080] The stator bracket 133 is also provided with an air outlet 139 that penetrates the base. The radial dimension of the air outlet 139 from the drive shaft 131 is greater than or equal to the radial dimension of the baffle 134 from the drive shaft 131, so that the cooling airflow will not touch the parts inside the second housing 132 during the downward flow, thus avoiding the loss of cooling airflow. This allows for greater utilization of the cooling airflow to cool the motor assembly 13.

[0081] The first housing 101 includes a connecting portion 103 extending outward from its outer peripheral wall and a first air inlet 104 communicating with the receiving cavity 102. The second housing 132 has a second air inlet 136 at one end away from the stator support 133 for the cooling airflow to enter. The outer wall of the second housing, the base, the baffle 134 and the inner wall of the first housing 101 together form an airflow path between the first air inlet and the second air inlet.

[0082] The cooling airflow enters the receiving cavity 102 through the first air inlet 104, forming an airflow channel between the second housing 132 and the first housing 101. This airflow channel is defined by the outer wall of the second housing 132, the baffle 134, and the inner wall of the first housing 101. Under the action of the first fan 14, the cooling airflow flows to the top of the second housing 132 and flows from the second air inlet 136 located at the top of the second housing 132 into the interior of the motor assembly 13. After passing through the motor assembly 13, the cooling airflow exits from the air outlet side 138 at the bottom of the stator bracket 133.

[0083] Please see Figure 10 The second fan 15 is located between the motor assembly 13 and the actuation assembly 11, and the second fan 15 is at least partially located outside the first housing 101. The second fan 15 and the actuation assembly 11 rotate together with the drive shaft 131, and there is no direct connection between the second fan 15 and the drive shaft 131. The second fan 15 is press-fitted between the first housing 101 and the actuation assembly 11.

[0084] Specifically, the second fan 15 includes an air guide portion 151 located inside the first housing 101 and near the air outlet side 138, an extension portion 152 located inside the first housing 101 and at a lower axial height than the air guide portion 151, a mating portion 153 located at least partially inside the first housing 101 and through which the drive shaft 131 passes, and a plurality of centrifugal fan blades 154 protruding from the first housing, the centrifugal fan blades being capable of generating centrifugal airflow to exhaust the cooling airflow from the first housing 101.

[0085] The lawnmower 100 includes a handle assembly 30 disposed opposite to the working component 10 and a connecting assembly 20 for connecting the working component and the handle assembly. One end of the connecting assembly 20 is connected to the working component 10, and the other end of the connecting assembly is connected to the handle assembly 30. A hollow channel is formed inside the connecting assembly 20. Several through holes communicating with the receiving cavity are provided on the lower part of the connecting assembly 20 near the working component 10. The through holes also communicate with the first air inlet 104 and the hollow channel. The number of through holes is not limited here. The through holes are opened below the connecting assembly 20 and are at a certain distance from the working component 10 to prevent grass clippings and other debris from entering the working component 10 through the through holes during the operation of the lawnmower 100, thereby affecting the normal operation of the working component 10.

[0086] When the lawnmower 100 is working, the first fan 14 rotates together with the drive shaft 131 to generate negative pressure. At this time, the cooling airflow enters the hollow channel through several through holes on the connecting assembly and enters the receiving cavity 102 through the first air inlet 104. Under the action of the first fan 14, the cooling airflow is drawn to the top of the second housing 132 and enters the interior of the motor assembly 13 through the second air inlet 136 located at the top of the second housing 132 to cool the motor assembly 13. Subsequently, under the action of the baffle 134 of the stator bracket 133, most of the cooling airflow flows out from the air outlet side 138 of the stator bracket 133. Under the action of the air guide 151 of the second fan 15, the cooling airflow after flowing through the motor assembly 13 is guided to the negative pressure area of ​​the second fan 15. Then, under the action of the centrifugal fan blade 154, the cooling airflow is discharged from the first housing 101, thereby improving the heat dissipation efficiency of the motor assembly 13.

[0087] This utility model integrates the advantages and disadvantages of existing heat dissipation methods and structures of handheld power tools / brush cutters with voltages of 12V and above, as well as their motors. It simplifies and optimizes the key structures in the motor cooling path, achieving a compact layout, lightweight appearance, and most importantly, efficient heat dissipation while ensuring simple manufacturing and assembly. This directly reduces the temperature of the motor components and improves their overcurrent and overload capacity, thereby improving the overall overload capacity and service life of the machine, and enhancing user work efficiency and operating experience.

[0088] This utility model is not limited to the specific embodiments described above. Those skilled in the art will readily understand that many alternative solutions exist for the power tools described in this application without departing from the principles and scope of this utility model. The scope of protection of this utility model is determined by the claims.

Claims

1. A power tool comprising: A first housing, a receiving cavity enclosed by the first housing, and a motor assembly received in the receiving cavity, the motor assembly including a drive shaft extending axially, a second housing sleeved on the drive shaft, and a plurality of magnets located on the inner wall of the second housing; characterized in that: the power tool includes a first fan rotating with the drive shaft, the first fan being located inside the second housing and including fan blades, a support portion connecting a plurality of fan blades, and a plurality of magnetically shielding portions extending from the support portion, each of the magnets being located between two adjacent magnetically shielding portions in a circumferential direction perpendicular to the axial direction.

2. The power tool of claim 1, wherein: Several of the magnetic shielding parts are spaced apart in the circumferential direction and are attached to the inner sidewall of the second housing.

3. The power tool of claim 1, wherein: The magnetic shielding part extends from the support part toward the side away from the fan blade, and the fan blade, the support part and the magnetic shielding part are integrally formed.

4. The power tool of claim 3, wherein: The support portion is connected to the radial outer periphery of the fan blade and forms a ring-shaped structure, and the outer peripheral wall of the support portion is fitted to the inner side wall of the second housing.

5. The power tool of claim 3, wherein: Each of the magnets abuts against the bottom side of the support in the axial direction and against the magnetically shielded part in the circumferential direction.

6. The power tool of claim 3, wherein: The second housing includes a fixed post connected to the drive shaft, and the first fan includes a mounting portion sleeved on the fixed post and a plurality of fan blades arranged circumferentially along the mounting portion, with one end of the plurality of fan blades connected to the mounting portion and the other end connected to the support portion.

7. The power tool of claim 6, wherein: The magnetic shielding part, the support part, the mounting part, and the fan blade are integrated into a single structure.

8. The power tool of claim 1, wherein: The motor assembly includes a stator support and a coil winding connected to the stator support. The magnetic shielding part and the magnet are spaced apart in the circumferential direction to surround the outer periphery of the coil winding, and there is a gap between the coil winding and the magnetic shielding part.

9. The power tool of claim 8, wherein: The stator support includes a base, a baffle integrally formed with the base, and an air outlet formed by the base and the baffle. The baffle extends into the interior of the second housing, and the air outlet is in fluid communication with the gap.

10. The power tool of claim 9, wherein: The first housing includes a first air inlet communicating with the outside, and the second housing includes a second air inlet communicating with the first air inlet. The fan blade, magnet and magnetic shield are located axially between the second air inlet and the air outlet.

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