Electric tool

Abstract

The utility model relates to an electric tool, which comprises a shell, a motor accommodated in the shell, a controller for driving the motor, a battery pack connected to the controller and supplying energy to the motor, a motor stator, a rotor and a fan, the shell is provided with an air inlet and an air outlet, and the air outlet is positioned on the front side of the air inlet. The fan sucks cooling airflow from the air inlet and discharges the cooling airflow from the air outlet, the cooling airflow flows through the controller and the motor, and the controller comprises a driving module for sending a driving instruction to the operation of the motor and a power module for executing the driving instruction; the power module comprises a power device, a control circuit board for mounting the power device, and a radiator connected to the control circuit board and in thermal contact with the power device, the control circuit board is connected with a capacitor, the radiator is provided with a mounting part connected to the control circuit board and a fin group extending from the mounting part to the shell, and the power device is fixed on the mounting part; and the capacitor is positioned between the at least two power devices and extends in a manner of being vertical or parallel to the mounting part.

Description

Technical Field

[0001] The utility model relates to the field of power tools, and particularly to a power tool for grinding and polishing processing scenarios.

Background Art

[0002] Power tools, especially DC tools, are often powered by a battery pack to enable a controller to drive a motor and a transmission component to operate, and then drive a top tool to perform processing operations. Among them, the controller usually has a control circuit board and power components such as IGBT or FET. These power components can execute instructions to drive the motor, and have the advantages of compact structure and high efficiency.

[0003] Furthermore, a large amount of heat is generated when the power components operate. This heat can be removed by a radiator arranged in cooperation with the power components to ensure the stable operation of the tool. However, since the internal space defined by the tool housing is relatively narrow, the area reserved for the radiator arrangement becomes relatively limited. At the same time, the controller also includes components such as capacitors that occupy the heat dissipation space. Therefore, how to obtain sufficient heat dissipation area in a narrow space is an important factor affecting the heat dissipation performance of the tool.

[0004] In view of this, it is necessary to provide an improved power tool to overcome the defects of the prior art.

Content of the Utility Model

[0005] Aiming at the deficiencies of the prior art, the purpose of the utility model is to provide a power tool with a compact overall structure while being able to fully dissipate heat and cool the control circuit board and power components of the controller.

[0006] This utility model solves the existing technical problems by adopting the following technical solution: An electric tool includes a housing, a motor housed in the housing, a controller for driving the motor, and a battery pack connected to the controller and supplying power to the motor. The housing has an axially spaced air inlet and an air outlet, with the air outlet located in front of the air inlet. The motor has a stator and a rotor connected to each other, and a fan connected to the rotor. The fan draws in cooling airflow from the air inlet and discharges the cooling airflow from the air outlet. The cooling airflow flows through the controller and the motor. The controller includes components connected to the battery pack and... A drive module that sends drive commands to the operation of the motor and a power module that executes the drive commands. The power module includes power devices that couple the stator to the battery pack, a control circuit board that mounts the power devices, and a heat sink that is connected to the control circuit board and in thermal contact with the power devices. The control circuit board is connected to a capacitor. The heat sink has a mounting portion connected to the control circuit board and a fin assembly extending from the mounting portion toward the housing. The power devices are fixed to the mounting portion. The capacitor is located between at least two of the power devices and extends perpendicularly or parallel to the mounting portion.

[0007] A further improvement is as follows: the mounting portion extends perpendicularly to the control circuit board, at least two of the power devices are located between a pair of mounting portions, the capacitor is located between a pair of mounting portions, and the extension direction of the capacitor is parallel to the mounting portion.

[0008] A further improvement is as follows: the fin assembly includes a first fin extending at an angle toward the corresponding side of the housing from each of the mounting portions and a plurality of second fins extending away from the control circuit board from the first fins. The extension direction of the second fins is parallel to the extension direction of the mounting portion. The mounting portion, the first fin, and the second fins have corrugated surfaces.

[0009] A further improvement is as follows: the fin assembly includes a plurality of third fins extending at an angle from each of the mounting portions toward the corresponding side of the housing, the plurality of third fins being parallel to each other, and the mounting portions and the third fins having corrugated surfaces.

[0010] A further improvement is as follows: the mounting part is a single unit, the mounting part has a through notch, and the capacitor is housed in the notch in the extending direction of the housing.

[0011] A further improvement is as follows: the mounting portion extends parallel to the control circuit board, at least two of the power devices are located between the control circuit board and the mounting portion, and the extension direction of the capacitor is perpendicular to the mounting portion.

[0012] A further improvement is as follows: the fin assembly includes a pair of fourth fins extending perpendicularly to the mounting portion, a plurality of fifth fins extending at an angle from each of the fourth fins toward the corresponding side of the housing, and a sixth fin extending at an angle from each of the fourth fins toward the capacitor. The extension length of the sixth fin is not greater than the extension length of the fifth fin. The mounting portion, the fourth fins, the fifth fins, and the sixth fin have corrugated surfaces.

[0013] A further improvement is that the fin assembly includes a plurality of seventh fins extending perpendicularly to the mounting portion and away from the control circuit board, each of the seventh fins having a different extension length.

[0014] A further improvement is that the power module has a package housing the control circuit board and the fin assembly, and the end of the fin assembly extends no more than the edge of the package housing.

[0015] A further improvement is as follows: the housing is equipped with a speed control knob for adjusting the speed of the motor, the speed control knob is connected to the drive module via a third signal line, each heat sink has at least two fin groups, and at least a portion of the third signal line is located between at least two fin groups.

[0016] Compared with the prior art, the present invention has the following advantages: by setting the controller into two parts, namely the drive module that sends drive commands and the power module that executes drive commands, the problem of insufficient heat dissipation efficiency of integrated controllers can be solved, and the heat dissipation performance of the tool controller can be improved; the power module includes a power device, a control circuit board for mounting the power device, and a heat sink connected to the control circuit board and in thermal contact with the power device, and the capacitor on the control circuit board is located between a pair of mounting parts of the heat sink, so that the capacitor will not affect the installation of the heat sink, improving the ease of assembly and also realizing the overall compactness of the power module. [Attached Image Description]

[0017] Figure 1 This is a perspective view of a power tool according to a preferred embodiment of the present invention;

[0018] Figure 2 yes Figure 1 The diagram shows the internal structure of the power tool.

[0019] Figure 3 yes Figure 1 A schematic diagram of the internal structure of the power tool shown from another perspective;

[0020] Figure 4 yes Figure 3 The diagram shows the wiring diagram of the internal components of the power tool.

[0021] Figure 5 yes Figure 1 The diagram shows the structure of the power module in the power tool shown.

[0022] Figure 6 yes Figure 5 A structural schematic diagram of the power module from another perspective;

[0023] Figure 7 This is a schematic diagram of the power module in the power tool according to the second embodiment of this utility model;

[0024] Figure 8 yes Figure 7 A structural schematic diagram of the power module from another perspective;

[0025] Figure 9 This is a schematic diagram of the power module in the power tool according to the third embodiment of this utility model;

[0026] Figure 10 yes Figure 9 An exploded view of the power module shown.

[0027] Figure 11 yes Figure 9 A schematic diagram of the power module from another perspective;

[0028] Figure 12 This is a schematic diagram of the power module in the power tool according to the fourth embodiment of this utility model;

[0029] Figure 13 yes Figure 12 An exploded view of the power module shown.

[0030] Figure 14 yes Figure 12 A schematic diagram of the power module from another perspective;

[0031] Figure 15 yes Figure 1 An exploded view of the transmission assembly in the power tool shown.

[0032] Figure 16 yes Figure 15 A schematic diagram of the output mechanism in the transmission assembly shown;

[0033] Figure 17 yes Figure 16 A schematic diagram of the output mechanism from another perspective;

[0034] Figure 18 yes Figure 16 A schematic diagram of the output mechanism from another perspective;

[0035] Figure 19This is a schematic diagram of the transmission assembly of the power tool according to the fifth embodiment of the present invention;

[0036] Figure 20 yes Figure 19 A schematic diagram of the output mechanism in the transmission assembly shown;

[0037] Figure 21 yes Figure 20 A schematic diagram of the output mechanism from another perspective;

[0038] Figure 22 yes Figure 20 The output mechanism shown is a structural schematic diagram from another perspective.

Detailed Implementation Methods

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0040] The terminology used in this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. For example, terms such as "upper," "lower," "front," "rear," "left," and "right," which indicate orientation or positional relationship, are based solely on the orientation or positional relationship shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device / component 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.

[0041] Please refer to Figures 1 to 3 This utility model relates to an electric tool 100 for polishing and grinding workpieces, with a polishing machine 100 being a preferred embodiment. As shown in the figures, the polishing machine 100 has a housing 1 extending along a first direction (front-back direction). The housing 1 consists of a first housing 11 accommodating a transmission assembly 6 and a second housing 12 accommodating a motor 2, a controller 3, and a switch assembly 5. The second housing 12 is further divided into a cylindrical portion 121 located at the front, a grip portion 122 connected to the rear of the cylindrical portion 121, and a battery mounting portion 123. The battery mounting portion 123 can be integrally formed with the grip portion 122 or detachably connected to the grip portion 122, thus changing the insertion direction of the battery pack 4 and providing the user with diverse gripping methods.

[0042] Please continue reading. Figures 1 to 3The motor 2 includes a stator 21 supported within the cylindrical portion 121 and a rotor 22 passing through the stator 21. The rotor 22 has a motor shaft 221 that extends into the first housing 11 along a first direction and has a fan 25 mounted at its front end. The motor 2 is driven by a controller 3. Since the polishing machine 100 generates a large amount of heat during operation, the controller 3 in this embodiment is a split type, consisting of a drive module 31 disposed within the battery mounting portion 123 and a power module disposed within the cylindrical portion 121. The power module 32 extends in the first direction, and the drive module 31 extends in a second direction (vertical direction) perpendicular to the first direction.

[0043] Furthermore, the drive module 31 is connected to the battery pack 4. A main control switch 51 and an operation switch 52 are respectively provided inside and outside the grip portion 122, forming a switch assembly 5. The power module 32 is located between the motor 2 and the main control switch 51. When the user presses the operation switch 52, the main control switch 51 receives a start signal. Subsequently, the drive module 31 sends a drive command to the power module 32 and simultaneously transmits current from the battery pack 4 to the power module 32. The power module 32 can then execute the aforementioned drive command to make the motor 2 run. The operation switch 51 does not extend beyond the edge of the battery mounting portion 123 in the second direction, so that the operation switch 51 will not be accidentally triggered when the polisher 100 is placed on a flat surface.

[0044] In addition, a Hall effect circuit board 23 is connected to the rear end of the stator 21. The Hall effect circuit board 23 is connected to the drive module 31 via a first signal line 231 to transmit the rotational information of the rotor 22 to the drive module 31. The drive module 31 can then control the rotor 22 to run at the required speed via the power module 32. Furthermore, the stator 21, the power module 32, the main control switch 51, and the drive module 31 are all connected by motor wires 2a to maintain a stable and reliable electrical connection.

[0045] Furthermore, if the user wants to manually change the speed of the motor 2, this utility model also provides a speed adjustment knob 24 on the cylindrical part 121. Specifically, the cylindrical part 121 has a base cylindrical part 121b and a first convex cylindrical part 121a and a second convex cylindrical part 121c respectively disposed on both sides of the base cylindrical part 121b. The first convex cylindrical part 121a is connected to the first housing 11, and the second convex cylindrical part 121c is connected to the gripping part 122. The diameter of the first convex cylindrical part 121a and the diameter of the second convex cylindrical part 121c are larger than the diameter of the base cylindrical part 121b. The speed adjustment knob 24 protrudes to the outside of the second convex cylindrical part 121c along the second direction.

[0046] The primary requirement for users operating the handheld polisher 100 is that it be compact and portable, and these characteristics are often determined by the arrangement of the components inside the polisher 100. In this embodiment, most of the components of the polisher 100 are concentrated in the cylindrical part 121, so the guiding arrangement within the cylindrical part 121 needs to be reorganized.

[0047] Please refer to Figures 1 to 4 The motor 2 is located within the base cylinder 121b and the first convex cylinder 121a in the first direction, and the power module 32 is located within the base cylinder 121b and the second convex cylinder 121c in the first direction. Therefore, the space within the entire cylindrical portion 121 becomes very limited. Before sorting out the wiring arrangement between the components, the structure of the power module 32 needs to be disassembled. Please refer to [reference needed]. Figures 2 to 3 The power module 32 is provided with an encapsulation box 327 with the opening facing upward. Inside the encapsulation box 327, a control circuit board 322 extending in the first direction is fixed by resin. A heat sink 323a and a power device 321a are mounted on the upper side of the control circuit board 322. The power device 321a and the control circuit board 322 are in thermal contact and execute motor drive commands from the drive module 31.

[0048] Further, turn to Figure 5 and Figure 6 In the power module 32 of this embodiment, there are two heat sinks 323a. Each heat sink 323a has a mounting portion 325a extending perpendicularly to the control circuit board 322, and the two mounting portions 325a are spaced apart from each other. Each mounting portion 325a has a fin assembly 326a extending toward the inner wall of the cylindrical portion 121, and the end of the fin assembly 326a does not exceed the edge of the encapsulation box 327. In addition, the fin assembly 326a includes a first fin 326a1 extending at an angle from the mounting portion 325a toward the corresponding side of the housing 1, and a plurality of second fins 326a2 extending from the first fin 326a1 away from the control circuit board 322. The extending direction of the second fins 326a2 is parallel to the extending direction of the mounting portion 325a. The mounting portion 325a, the first fin 326a1 and the second fins 326a2 have corrugated surfaces, which help to increase the heat dissipation area of ​​the heat sink 323a.

[0049] Furthermore, in this power module 32, the power devices 321a are IGBT or FET transistors, and there are six of them, arranged in two rows. Each power device 321a is fixed to the mounting portion 325a perpendicular to the control circuit board 322. There are three of them in each mounting portion 325a, meaning that all the power devices 321a are located between a pair of mounting portions 325a. In addition, the power module 32 has a capacitor 324 for protecting the power devices 321a disposed in the gap between the two fin groups 326a. The capacitor 324 extends perpendicular to the control circuit board 322 toward the inner wall of the cylindrical portion 121. The capacitor 324 is disposed between the two rows of power devices 321a, which enables the power module 32 to be compact.

[0050] Combination Figures 1 to 4 The wiring within the cylindrical portion 121 is described below, defined as follows: the power module 32 and the housing 1 form a first wiring space 1c in the second direction; the main control switch 51 and the grip portion 122 form a second wiring space 1d in the third direction (left-right direction); and the main control switch 51 and the grip portion 122 form a third wiring space 1e in the second direction. Therefore, in the path from the first signal line 231 on the Hall circuit board 23 to the drive module 31, the first signal line 231 passes through the first wiring space 1c and the second wiring space 1d. The control circuit board 322 within the power module 32 is connected to the drive module 31 via a second signal line 322a, which passes through the first wiring space 1c and the third wiring space 1e. The speed control knob 24 is connected to the drive module 31 via a third signal line 24a, at least a portion of which is located between the two fin groups 326a. Additionally, the motor wire 2a of the stator 21 passes through the third wiring space 1e. In the above structure, by defining the first wiring 1c, the second wiring space 1d, and the third wiring space 1e within the second housing 12, the crossover of wires between various electronic and mechanical components is avoided, ensuring the stable operation of the controller 3 and the motor 2.

[0051] Please continue reading. Figures 1 to 6 Because the power devices 321a and motor 2 on the drive module 32 generate a large amount of heat during the operation of the polishing machine 100, this utility model is equipped with an air inlet 1a and an air outlet 1b. (Continue to...) Figures 1 to 3 The air inlet 1a penetrates the second protruding cylindrical part 121c along the third direction, and its air inlet surface is directly opposite the heat sink 323a of the power module 32. The air outlet 1b penetrates the first housing 11 along the third direction, and its air outlet surface is directly opposite the fan 25. The air inlet area of ​​the air inlet 1a is larger than the exhaust area of ​​the air outlet 1b.

[0052] When the polishing machine 100 is running, the fan 25 rotates under the drive of the rotor 22. The cold airflow outside the housing 1 enters through the air inlet 1a and blows directly onto the power device 321a and the heat sink 323a, thereby carrying away the heat on the power device 321a and the heat sink 323a. Then the cooling airflow flows through the motor 2, further carrying away the heat on the motor 2. Finally, the cooling airflow is discharged from the exhaust port 1b. The air inlet surface of the air inlet 1a and the air outlet surface of the exhaust port 1b are set on the same side of the housing 1, which allows the airflow to flow in an "I" shape between the air inlet 1a and the exhaust port, thereby ensuring that the power device 321a, the heat sink 323a and the motor 2 are adequately cooled.

[0053] In addition, the battery mounting section 123 is provided with an auxiliary air inlet 1c, and the first housing 11 is provided with an auxiliary air outlet 1d. At least a portion of the drive module 51 is opposite to the air inlet surface of the auxiliary air inlet 1c, and the exhaust surface of the auxiliary air outlet 1d is perpendicular to the exhaust surface of the exhaust port 1b. The air inlet area of ​​the auxiliary air inlet 1c is smaller than the air inlet area of ​​the air inlet 1a. By providing the auxiliary air inlet 1c and the auxiliary air outlet 1d, the heat inside the housing 1 of the polishing machine 100 can be further discharged, thereby improving the tool's efficiency and lifespan.

[0054] Please see Figures 15 to 18 As shown, the transmission assembly of the polishing machine includes an output shaft 61, an output mechanism 62, and an offset output shaft 624. The output shaft defines a first rotation axis X1 and is connected to the motor shaft 221 via a bevel gear system. The output mechanism 62 is connected between the output shaft 61 and the offset output shaft 624 to transmit the torque of the motor 2 to the tip tool 7 connected to the offset output shaft 624, so that the tip tool 7 moves in one or more ways, either in a rotational or orbital manner. The tip tool is preferably a polishing pad or a polishing disc.

[0055] The output mechanism 62 includes a sleeve 621a that receives the output shaft 61, a cam 622a connected to the sleeve 621a and extending toward the top tool 7, and a first balancing portion 623a extending radially from the cam 622a. The sleeve 621a has a first receiving space 621a1, the cam has a second receiving space 622a1, the first receiving space 621a1 and the second receiving space (622a1) are in communication, the output shaft 61 is mounted in the first receiving space 621a1, and the biased output shaft 624 is pivotally mounted in the second receiving space 622a1 by a bearing and defines a second rotation axis X2, which is parallel to the first rotation axis X1.

[0056] The output mechanism 62 also includes a base plate 62a1 connected to the sleeve 621a and the cam. The sleeve 621a is located on the surface of the base plate 62a1 facing the output shaft 61, and the cam 622a is located on the surface of the base plate 62a1 facing the top tool 7. In addition, the first balancing part 623a has a balancing mounting part 625a connected to the circumferential surface of the cam 622a and a balancing block 626a extending from the balancing mounting part 625a. The balancing mounting part 625a, the base plate 62a1, and the cam 622a are integrally formed. The balancing block 626a is fan-shaped, and the projections of the balancing mounting part 625a and the sleeve 621a onto the first housing 11 along the direction of the first rotation axis X1 at least partially overlap.

[0057] Furthermore, the balance block 626a and the substrate 62a1 are spaced apart in the extension direction of the first rotation axis X1. Simultaneously, the distance from the radial outer end of the substrate 62a1 to the first rotation axis X1 is approximately equal to the distance from the radial outer end of the balance block 626a to the first rotation axis X1. This allows the output mechanism 62 to have a certain degree of balance in both the axial and radial directions. Additionally, the balance block 626a has through holes 62a2, with at least two rows of through holes 62a2. The line connecting the centers of each row of through holes 62a2 is an arc, thus eliminating excess counterweight on the balance block 626a.

[0058] In addition, since no balancing element is provided on the side of the cam 622a away from the balance block 626a in this embodiment, and the balancing measures are only carried out by the base plate 62a1 and the balance block 626a, the second rotation axis X2 is extended through the sleeve 621a in order to further stabilize the balance of the output mechanism 62.

[0059] When the polishing machine 100 is started, the output shaft 61 rotates around the first rotation axis X1, and the output mechanism 62, driven by the output shaft 61, also rotates around the first rotation axis X1. At this time, the offset output shaft 624, under the action of the output shaft 61 and the output mechanism 62, will drive the tip tool 7 to exhibit two forms of motion: one is the rotational motion of the tip tool 7 itself around the second rotation axis X2; the other is the orbital motion of the tip tool 7 around the first rotation axis X1 in an approximately elliptical trajectory. Based on the above two motions, the tip tool can perform efficient and precise polishing and grinding operations.

[0060] Please see Figure 1 , Figure 7 and Figure 8As shown, in the second embodiment of this utility model, the overall structure of the polishing machine 100 is roughly the same as that of the polishing machine 100 in the first embodiment. There are two heat sinks 323b in the power module 32, and the mounting part 325b extends perpendicularly to the control circuit board 322 and is spaced apart from each other. The style and mounting method of the power device 312a and the capacitor 324 are the same as those in the first embodiment.

[0061] The difference lies in the fact that, in the second embodiment, each fin group 326b of the power module 32 includes a plurality of third fins 326b1 extending from the mounting portion 325b toward the corresponding side of the housing 1 at an angle. The plurality of third fins 326b1 are parallel to each other, and the tilt angle is preferably 30 degrees to 80 degrees. In addition, the mounting portion 325b and the third fins 326b1 have corrugated surfaces.

[0062] Please see Figure 1 , Figures 9 to 11 In the third embodiment of this utility model, the overall structure of the polishing machine 100 is roughly the same as that of the polishing machine 100 in the first embodiment. The difference is that in the power module 32 of this embodiment, the heat sink 323c is an integral structure, including a mounting part 325c extending parallel to the control circuit board 322 and a pair of fin groups 326c arranged from the mounting part 325c toward the interior of the housing 1.

[0063] Specifically, the fin assembly 326c includes a pair of fourth fins 326c1 extending perpendicularly to the mounting portion 325c, a plurality of fifth fins 326c2 extending at an angle from the fourth fins 326c1 toward the corresponding side of the housing 1, and a sixth fin 326c3 extending at an angle from the fourth fins 326c1 toward the capacitor 324. Each fifth fin 326c2 is parallel to each other, and each sixth fin 326c3 is also parallel to each other. The mounting portion 325c, the fourth fins 326c1, the fifth fins 326c2, and the sixth fin 326c3 all have corrugated surfaces.

[0064] Furthermore, the extension length of the sixth fin 326c3 is no greater than the extension length of the fifth fin 326c2. This is because sufficient space needs to be reserved between the two rows of sixth fins 326c3 for the installation of capacitor 324. In addition, the extension angle of the sixth fin 326c3 and the extension angle of the fifth fin 326c2 should be basically equal, so that the cooling airflow can have basically the same flow characteristics when flowing through the fifth fin 326c2 and the sixth fin 326c3, and further carry away basically the same amount of heat.

[0065] Furthermore, in this embodiment, the power device 321b is a surface-mount IGBT or FET, which is mounted on the control circuit board 322 parallel to the mounting portion 325c and abuts against the lower surface of the mounting portion 325c. It is worth noting that the mounting portion 325c has a through-hole 328 between the two fin groups 326c. The capacitor 324 mounted on the control circuit board 322 extends through the through-hole 328 and is perpendicular to the mounting portion 325c. Additionally, viewed from the first direction, the capacitor 324 is housed within the through-hole 328. Furthermore, the power devices 321b are distributed in two rows on either side of the through-hole 328 and the capacitors 324, with three or more power devices per row. This arrangement ensures stable operation of the power module 32 without increasing its size.

[0066] Please see Figure 1 , Figures 12 to 14 In the fourth embodiment of this utility model, the overall structure of the polishing machine 100 is roughly the same as that of the polishing machine 100 in the first embodiment, with the only difference being the structure of the power module 32. Furthermore, in the power module 32 of this embodiment, the structural forms of the mounting portion 325d of the heat sink 323d, the power device 321b, the capacitor 324, and the notch 328 of the control circuit board 322, as well as the arrangement of the components, are the same as in the third embodiment described above. Additionally, the two sets of fins 326d of the heat sink 323d are also spaced apart on both sides of the notch 328.

[0067] The power module 32 in this embodiment differs from that in the third embodiment in that the fin group 326d has multiple seventh fins 326d1 extending perpendicularly to the mounting portion 325d. The extension length of each seventh fin 326d1 is different. Optionally, the middle seventh fin 326d1 has a longer extension length, while the extension length of the seventh fins 326d1 on both sides is shorter.

[0068] Please refer to Figures 19 to 22 In the fifth embodiment of this utility model, the overall structure of the polishing machine 100 is roughly the same as that of the polishing machine 100 in the first embodiment, and the output mechanism 62 also has the following similarities with the first embodiment.

[0069] The output mechanism 62 includes a sleeve 621b that receives the output shaft 61, a cam 622b connected to the sleeve 621b and extending toward the tip tool 7, and a first balancing portion 623b extending radially from the cam 622b. The projections of the sleeve 621b and the first balancing portion 623b on the first housing 11 at least partially overlap, and a second rotation axis X2 extends through the sleeve 621b. Further, the first balancing portion 623b has a balancing mount 625b connected to the circumferential surface of the cam 622b and a balancing block 626b extending from the balancing mount 625b, the balancing block 626b being fan-shaped.

[0070] The difference between the output mechanism 62 in this embodiment and the first embodiment is that: the sleeve 621b and the cam 622b are integrally formed, the sleeve 621b is at least partially located on the radially outer side of the cam 622b, the balance mounting part 625b extends radially outward from the outer surface of the sleeve 621b and the cam 622b, the balance mounting part 625b is fan-shaped, the balance block 626b and the balance mounting part 625b are integrally formed, and the axial end face of the balance block 626b facing the output shaft 61 is flush with the axial end face of the cam 622b facing the output shaft 61 in the extension direction of the first rotation axis X1.

[0071] In addition, a second balancing part 62b1 is integrally connected to the axial end face of the cam 622b facing the output shaft 61. The second rotation axis X2 passes through the second balancing part 62b1. The second balancing part 62b1 extends beyond the sleeve 621b in the extension direction of the second rotation axis X2. The second balancing part 62b1 protrudes radially to the outside of the cam 622b.

[0072] Furthermore, the second balancing part 62b1 is fan-shaped, and the central angle of the second balancing part 62b1 is not greater than the central angle of the balancing block 626b. Preferably, the central angles of the two are equal. At the same time, the balancing block 626b and the second balancing part 62b1 are respectively disposed on both sides of the first rotation axis (X1). The axial end face of the balancing block 626b facing the output shaft 61 and the axial end face of the second balancing part 62b1 facing away from the output shaft 61 are flush in the extension direction of the first rotation axis X1.

[0073] This utility model is not limited to the specific embodiments described above. Those skilled in the art will readily understand that many other alternative solutions exist for the power tool of this utility model 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. An electric tool, comprising a housing, a motor housed within the housing, a controller for driving the motor, and a battery pack connected to the controller and supplying power to the motor, the housing having an axially spaced air inlet and an air outlet, the air outlet being located in front of the air inlet, the motor having a stator and a rotor interconnected thereto, and a fan connected to the rotor, the fan drawing in cooling airflow from the air inlet and discharging the cooling airflow from the air outlet, the cooling airflow flowing through the controller and the motor; characterized in that: The controller includes a drive module connected to the battery pack and sending drive commands to the motor, and a power module executing the drive commands. The power module includes power devices that couple the stator to the battery pack, a control circuit board that mounts the power devices, and a heat sink connected to the control circuit board and in thermal contact with the power devices. The control circuit board is connected to a capacitor. The heat sink has a mounting portion connected to the control circuit board and a fin assembly extending from the mounting portion toward the housing. The power devices are fixed to the mounting portion, and the capacitor is located between at least two of the power devices, extending perpendicularly or parallel to the mounting portion.

2. The power tool according to claim 1, characterized in that: The mounting portion extends perpendicular to the control circuit board, at least two of the power devices are located between a pair of the mounting portions, the capacitor is located between a pair of the mounting portions, and the extension direction of the capacitor is parallel to the mounting portion.

3. The power tool according to claim 2, characterized in that: The fin assembly includes a first fin extending at an angle toward a corresponding side of the housing from each of the mounting portions and a plurality of second fins extending away from the control circuit board from the first fins. The extension direction of the second fins is parallel to the extension direction of the mounting portions. The mounting portions, the first fins, and the second fins have corrugated surfaces.

4. The power tool according to claim 2, characterized in that: The fin assembly includes a plurality of third fins extending at an angle toward a corresponding side of the housing from each of the mounting portions, the plurality of third fins being parallel to each other, and the mounting portions and the third fins having corrugated surfaces.

5. The power tool according to claim 1, characterized in that: The mounting portion is a single unit, which has a through notch, and the capacitor is housed in the notch in the extending direction of the housing.

6. The power tool according to claim 5, characterized in that: The mounting portion extends parallel to the control circuit board, at least two of the power devices are located between the control circuit board and the mounting portion, and the extension direction of the capacitor is perpendicular to the mounting portion.

7. The power tool according to claim 6, characterized in that: The fin assembly includes a pair of fourth fins extending perpendicularly to the mounting portion, a plurality of fifth fins extending at an angle from each of the fourth fins toward a corresponding side of the housing, and a sixth fin extending at an angle from each of the fourth fins toward the capacitor. The extension length of the sixth fin is not greater than the extension length of the fifth fin. The mounting portion, the fourth fins, the fifth fins, and the sixth fin have corrugated surfaces.

8. The power tool according to claim 6, characterized in that: The fin assembly includes a plurality of seventh fins extending perpendicular to the mounting portion and away from the control circuit board, each of the seventh fins having a different extension length.

9. The power tool according to claim 1, characterized in that: The power module has a package housing the control circuit board and the fin assembly, the ends of the fin assembly extending beyond the edge of the package housing.

10. The power tool according to claim 1, characterized in that: The housing is equipped with a speed control knob for adjusting the speed of the motor. The speed control knob is connected to the drive module via a third signal line. Each heat sink has at least two fin groups, and at least a portion of the third signal line is located between at least two fin groups.

Images