Air duct system and power tool

Abstract

The present application relates to a kind of air duct systems, including shell, motor assembly housed in shell and the air duct mechanism of cooling motor assembly, motor assembly has fixed stator in shell and the rotor of passing in stator, air duct mechanism has the drive fan installed in rotor, drive fan rotation generates cooling gas, air duct mechanism includes by the flow guide member rotated by cooling gas, first air duct formed between stator and shell and the second air duct independent of first air duct, second air duct is at least partially downstream of flow guide member, and, angle grinder using the air duct system has excellent heat dissipation performance and dustproof performance.

Description

[Technical Field]

[0001] This invention relates to the field of power tool technology, and in particular to an air duct system and a power tool using the air duct system. [Background Technology]

[0002] Power tools are a type of tool that uses a motor to drive an output accessory to perform operations on a workpiece. During the machining process of power tools, the control components and motor components generate a large amount of heat. This heat can be carried away by the cooling airflow generated by the rotating drive fan and discharged from the machine. However, the cooling airflow will also bring in dust generated by the tool operation when it enters the machine. Furthermore, in grinding tools with permanent magnet rotors, when the dust-laden cooling air flows through the motor, the dust will be attracted by the rotor, affecting the motor efficiency and even causing the motor to fail. In addition, the dust can also impact the stator coil, posing a risk of puncturing the coil and further leading to short circuits and / or open circuits.

[0003] Currently, the method to prevent dust from entering the motor of power tools is to add a dust filter at the air inlet. The dust filter has a certain blocking effect on larger dust particles. However, the dust filter is less effective at blocking dust particles smaller than the mesh size. These smaller dust particles can still enter the motor and cause damage to the motor.

[0004] Therefore, it is necessary to provide a new type of air duct system and a power tool using the air duct system to overcome the deficiencies of the prior art. [Summary of the Invention]

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide an air duct system and an electric tool using the air duct system, which enables the electric tool to have excellent heat dissipation and dust prevention performance.

[0006] The present invention addresses the problems of the prior art by adopting the following technical solution: a duct system, comprising a housing, a motor assembly housed within the housing, and a duct mechanism for cooling the motor assembly, wherein the motor assembly has a stator fixed to the housing and a rotor passing through the stator, the duct mechanism having a drive fan mounted on the rotor, the drive fan rotating to generate cooling gas, and the duct mechanism including a guide member driven to rotate by the cooling gas, a first duct formed between the stator and the housing, and a second duct independent of the first duct, the second duct being at least partially located downstream of the guide member.

[0007] A further improvement is as follows: the cooling gas flows through the first air duct and the second air duct, and the dust entrained in the cooling gas is guided into the first air duct by the guide component.

[0008] A further improvement is as follows: the housing has a grid connected to the inner wall, the rotor is supported on the grid by a second bearing, the first air duct is formed between the outer wall of the grid, the outer wall of the stator and the inner wall of the housing, and the second air duct is formed between the guide member and the grid.

[0009] A further improvement is as follows: the guide component includes a hub, a ring slope extending from the hub, and a baffle ring connected to the ring slope; the grille has an inner ring, an outer ring connected to the inner ring, and a grille vent disposed between the inner and outer rings; the baffle ring and the outer ring form a labyrinthine channel; the labyrinthine channel is the inlet section of the second air duct; and the grille vent communicates with the labyrinthine channel.

[0010] A further improvement is as follows: the guide member is provided with a combined blade on the surface of the annular slope. The combined blade has a first blade connected to the root of the annular slope, a first blade extending from the root in a bent manner and deviating from the axial direction, and a second blade extending along the axial direction. The surface area of ​​the first blade is larger than the surface area of ​​the second blade.

[0011] A further improvement is as follows: the first blade is the force-receiving end of the cooling gas driving the guide to rotate, and the second blade is the force-applying end of the guide throwing the dust.

[0012] A further improvement is that the rotation center of the guide element coincides with the rotation center of the rotor.

[0013] A further improvement is as follows: the stator has a stator core, an end plate abutting against the end face of the stator core, and a cover plate abutting against the end face of the end plate. The outer ring of the grille abuts against the end face of the cover plate. The end plate forms an end plate gap. The cover plate has a cover plate vent. The grille vent, the cover plate vent, and the end plate gap are connected.

[0014] The present invention can also solve the problems of the prior art by adopting the following technical solution: an electric tool, including a housing, a motor assembly housed in the housing, a control assembly for driving the motor assembly, and an air duct mechanism for cooling the motor assembly and the control assembly. The motor assembly has a stator fixed to the housing and a rotor passing through the stator. The air duct mechanism has a drive fan installed on the rotor. The drive fan rotates to generate cooling gas. The cooling gas flows through the control assembly and the motor assembly. The air duct mechanism includes a guide member disposed between the motor assembly and the control assembly, a first air duct formed between the stator and the housing, and a second air duct independent of the first air duct. The second air duct is at least partially located downstream of the guide member.

[0015] A further improvement is as follows: the cooling gas flows through the first air duct and the second air duct, and the dust entrained in the cooling gas is guided into the first air duct by the guide component.

[0016] A further improvement is as follows: the housing has a grid connected to the inner wall, the rotor is supported on the grid by a second bearing, the flow guide is located between the grid and the control component, the first air duct is formed between the outer wall of the grid, the outer wall of the stator and the inner wall of the housing, and the second air duct is formed between the flow guide and the grid.

[0017] A further improvement is as follows: the guide component includes a hub, a ring slope extending from the hub, and a baffle ring connected to the ring slope; the grille has an inner ring, an outer ring connected to the inner ring, and a grille vent disposed between the inner and outer rings; the baffle ring and the outer ring form a labyrinthine channel; the labyrinthine channel is the inlet section of the second air duct; and the grille vent communicates with the labyrinthine channel.

[0018] A further improvement is as follows: the guide member is provided with a combined blade on the surface of the annular slope. The combined blade has a first blade connected to the root of the annular slope, a first blade extending from the root in a bent manner and deviating from the axial direction, and a second blade extending along the axial direction. The surface area of ​​the first blade is larger than the surface area of ​​the second blade.

[0019] A further improvement is as follows: the first blade is the force-receiving end of the cooling gas driving the guide to rotate, and the second blade is the force-applying end of the guide throwing the dust.

[0020] A further improvement is that the rotation center of the guide component coincides with the rotation center of the rotor. A further improvement is that the power tool is an angle grinder.

[0021] Compared with the prior art, the present invention has the following beneficial effects: by applying an air duct system with an air duct mechanism to an angle grinder, the angle grinder can have excellent heat dissipation and dust prevention performance. Specifically:

[0022] 1. The air duct mechanism has a guide component located between the motor assembly and the control assembly. While the cooling gas drives the guide component to rotate, the guide component can also throw the dust entrained in the cooling gas to the outside of the motor assembly, which can effectively prevent dust from entering the interior of the motor assembly.

[0023] 2. The first blade of the guide is configured as an arc-shaped blade that deviates from the axial direction and extends in a bent manner, which can improve the guiding effect of the guide on the cooling gas; the second blade of the guide is constructed as an upright blade that extends along the axial direction, which can ensure the dust throwing effect of the guide.

[0024] 3. The guide vane is equipped with a counterweight ridge on the hub and blade ribs on the retaining ring, which can improve the balance of the guide vane during rotation.

[0025] 4. The air duct mechanism forms a first air duct between the outer wall of the grille, the outer wall of the stator, and the inner wall of the main housing, and a second air duct between the guide and the grille. The dual air duct structure of the first and second air ducts can ensure the heat dissipation performance of the motor assembly.

[0026] 5. The labyrinthine channel formed by the guide and the grille, together with the grille window formed by the grille, constitutes a second air duct. Dust can only enter the motor assembly through the second air duct, thus further reducing the probability of dust entering the motor assembly.

[0027] 6. A dustproof component is provided between the motor assembly and the grille. Even if dust enters the motor assembly through the second air duct, the dustproof component can throw the dust away when the rotor drives it to rotate, preventing it from entering the air gap between the rotor and the stator. [Image Description]

[0028] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings:

[0029] Figure 1 This is a perspective view of a power tool according to a preferred embodiment of the present invention;

[0030] Figure 2 yes Figure 1 The diagram shown is a schematic of the air duct system for power tools.

[0031] Figure 3 yes Figure 2 A schematic diagram of the structure of the second cylindrical part in the power tool shown;

[0032] Figure 4 yes Figure 2 The diagram shows the structure of the motor assembly and air guide in the air duct system shown.

[0033] Figure 5 yes Figure 4 A schematic diagram of the internal structure of the flow guide shown;

[0034] Figure 6 yes Figure 2 The diagram shows the assembly of the control components and the flow guide.

[0035] Figure 7 yes Figure 3 The diagram shows the assembly of the second cylindrical section and the guide component.

[0036] Figure 8 yes Figure 2 The diagram shows the operation of the air duct system. [Detailed Implementation]

[0037] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. For example, terms such as "upper," "lower," "front," and "rear" that 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, 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 a limitation of the invention.

[0038] Please refer to Figures 1 to 2 This invention relates to an electric tool 100 equipped with an air duct system 200. In this embodiment, the electric tool 100 is preferably an angle grinder 100, which is an AC brushless angle grinder adapted to a 220V power supply. A control component 3 housed within a housing 1 drives a motor assembly 2, which in turn drives a transmission assembly 5, causing the tip assembly 6 to work on the workpiece. During operation, the grinding operation of the tip assembly 6 generates a large amount of dust and other contaminants. These contaminants can enter the motor assembly 2 and damage it. Furthermore, the operation of the control component 3 and the motor assembly 2 generates a large amount of heat. If this heat is not dissipated in time, it can burn out the angle grinder 100. Therefore, the purpose of equipping the angle grinder 100 with the air duct system 200 is to dissipate heat and prevent dust accumulation.

[0039] The housing 1 includes a main housing 11, a rear cover 12, a gearbox 13, and a gearbox cover 14. The main housing 11 has two parts: a first cylindrical part 111 and a second cylindrical part 112. The inner diameter of the first cylindrical part 111 is larger than the inner diameter of the second cylindrical part 112. The motor assembly 2 is installed inside the second cylindrical part 112. When the user operates the angle grinder 100, he can grasp the outer surface of the second cylindrical part 112 with his palm and rest the back of his hand against the first cylindrical part 111, which can prevent the angle grinder 100 from being thrown off.

[0040] Please refer to Figure 3The inner surface of the second cylindrical portion 112 is defined as the mounting wall 113, and the grille 114 is fixed to the right side of the mounting wall 113. Specifically, the grille 114 has an inner ring 114a and an outer ring 114b. The inner ring 114a is annular, and a central hole 114g is formed inside it. The outer ring 114b is composed of an outer ring base 114h and an outer ring side ring 114i. The outer ring base 114h is connected to the mounting wall 113 through an outer grid bar 114d, and the outer grid bar 114d... The annular space between the two is divided into several regions, which are defined as ventilation gaps 114f; the outer ring side ring 114i of the grille extends axially from the right end face of the outer ring base 114h of the grille, and the outer ring side ring 114i of the grille and the inner ring 114a of the grille have the same center. The outer ring side ring 114i of the grille and the inner ring 114a of the grille are connected by an inner grid 114c, which divides the annular space between the two into several regions, which are defined as grille vents 114e.

[0041] On the right side of the grille 114, the mounting wall 113 is provided with a guide mechanism 115. Preferably, there are three guide mechanisms 115. Each guide mechanism 115 includes a first rib 115a and a second rib 115b extending from the rightmost end of the mounting wall 113 to the left. The first rib 115a and the second rib 115b are spaced apart by a certain gap. Furthermore, both the first rib 115a and the second rib 115b have a slot 115c extending through their right end faces. Further, the guide mechanism 115 is equipped with a limiting mechanism 116, which includes a base 116a and a side portion 116b. The base 116a has a width in the front-to-back direction equal to the distance between the first rib 115a and the second rib 115b. There are two side portions 116b, which are perpendicular to the base 116a. The support portion 116c is perpendicular to the side portions 116b and extends in a direction away from the side portions 116b. The radial thickness of the support portion 116c is equal to the radial depth of the slot 115c. When the limiting mechanism 116 is installed onto the guide mechanism 115, the support portion 116c can be aligned with the slot 115c. Then, the limiting mechanism 116 is fully pushed in to complete the installation.

[0042] Please continue to refer to Figure 1 and Figure 2The rear cover 12 is the place to house the control component 3, which is installed at the right end of the main housing 11. Air inlets 121 are opened on both the front and rear end faces, and a switch hole 122 and a power hole 123 are opened on the right end face. The switch hole 122 is located above the power hole 123. The head cover is used to install the transmission component 5 and is divided into three spaces: the first cavity 131, the middle cavity 132, and the second cavity 133. The first cavity 131 is located at the right end of the gearbox 13 and is connected to the main housing 11. An air outlet 134 is passed through the left end face of the first cavity 131. The second cavity 133 is located at the lower left end of the first cavity 131. The middle cavity 132 connects the first cavity 131 and the second cavity 133.

[0043] A transmission assembly 5 is installed inside the gearbox 13. The transmission assembly 5 includes a first bevel gear 51 installed in the intermediate cavity 132, a second bevel gear 52 installed in the second cavity 133, and an output shaft 53 passing through the second bevel gear 52. A gearbox cover 14 is installed at the lower end of the gearbox 13. A top assembly 6 is installed at the lower end of the gearbox cover 14. The top assembly 6 includes a working disc 61 fixed to the output shaft 53 and a pressure plate 62 for clamping the working disc 61. A protective cover 63 is installed on the outside of the gearbox cover 14. The protective cover 63 covers at least part of the circumference of the working disc 61. When the user operates the angle grinder 100 by hand, the protective cover 63 can effectively protect the user's hand safety.

[0044] Please refer to Figures 2 to 4 Next, the motor assembly 2 is described. The motor assembly 2 includes a stator 21 and a rotor 22. The stator 21 is mainly composed of a stator core 211 and a coil 212. The stator core 211 is held in the mounting wall 113 and has multiple storage holes 211a through it. Each storage hole 211a is equipped with an insulating bracket 211b. The coil 212 is formed by winding enameled wire between multiple insulating brackets 211b.

[0045] The right end of the stator core 211 is connected to an end plate 213. The end plate 213 includes an end plate base 213a that fits against the right end face of the stator core 211, an end plate side ring 213b that extends to the right perpendicularly to the end plate base 213a, and an end plate inner ring 213c. The outer diameter of the end plate base 213a, the outer diameter of the stator core 211, and the outer diameter of the grid outer ring base 114h are approximately equal. The right end face of the end plate base 213a has several evenly distributed end plate protrusions 213d. An end plate gap 213e is provided between the end plate side ring 213b and the end plate inner ring 213c, which can be used to accommodate the part of the coil 212 that is exposed in the stator core 211. An end plate center hole 213f is formed inside the end plate inner ring 213c, which can be used to place the rotor 22.

[0046] A cover plate 214 is installed on the right end of the end plate 213. The cover plate 214 has an inner ring 214a and an outer ring 214b in a circular shape. The outer diameter of the outer ring 214b is equal to the outer diameter of the end plate base 213a. The inner ring 214a and the outer ring 214b are connected by a rib 214c, which divides the annular space between them into several regions, which are defined as cover plate vents 214d. A central hole 214e is provided in the center of the inner ring 214a. The outer ring 214b... The circumferential surface of 14b has several spaced cover plate notches 214f; when the cover plate 214 is installed to the right end of the end plate 213, the inner ring 213c of the end plate passes through the inner ring 214a of the cover plate, and the end plate protrusion 213d passes through the cover plate notch 214f. At this time, the stator core 211, end plate 213, cover plate 214 and grid 114 are in close contact with each other, that is, the outer circumferential surface formed by the four is a closed circle. In the internal space formed by the four, the grid window 114e, the cover plate window 214d and the end plate gap 213e are connected.

[0047] The rotor 22 is fixed inside the stator 21 and mainly includes a rotor shaft 221 and a rotor core 222 installed on the outside of the rotor shaft 221. The left end of the rotor shaft 221 is installed in the intermediate cavity 132 of the gearbox 13 through a first bearing 223, and the right end of the rotor shaft 221 is installed in the internal space formed by the inner ring 114a of the grille through a second bearing 224. An air gap 24 is formed between the rotor core 222 and the stator core 211. The air gap 24, the end plate center hole 213f, the cover plate center hole 214e, and the grille vent 214d are connected. Between the cover plate 214 and the grille 114, a dustproof component 23 is installed on the rotor shaft 221. The dustproof component 23 is constructed as a centrifugal fan. The maximum outer diameter of the dustproof component 23 is smaller than the diameter of the inner ring 214a of the cover plate and the diameter of the inner ring 114a of the grille.

[0048] Please refer to Figure 2 , Figure 6 and Figure 7 The control component 3 is installed at the right end of the grille 114 and is held in place by the encapsulation box 31 on the inner wall of the rear cover 12. The encapsulation box 31 is roughly a hollow cuboid with an opening 311 on its lower side. The left end face of the encapsulation box 31 has a circular recess 312. A flange 313 concentric with the recess 312 is provided on the inner side of the recess 312. A boss 314 concentric with the flange 313 extends to the left from the surface of the flange 313. A threaded hole 314a is passed through the inside of the boss 314.

[0049] A push-button switch 32 is located near the top of the right end face of the encapsulation box 31, and the push-button switch 32 is exposed through the switch hole 122 on the rear cover 12. A circuit board 33 is mounted on the upper inner wall of the encapsulation box 31, and the circuit board 33 is connected to the push-button switch 32. In addition, the power cord can pass through the power hole 123 on the rear cover 12 and connect to the circuit board 33. Furthermore, in order to ensure the stable and efficient operation of the motor assembly 2, the control component 3 and the motor assembly 2 should have excellent electrical connectivity. In this embodiment, the connection between the control component 3 and the motor assembly 2 is ensured by connecting wires 215 between the three phases of the stator 21 and the circuit board 33. In order to receive the current from the power supply, the lower surface of the circuit board 33 is provided with electronic components such as inductor 37, capacitor 36 and IGBT 35 from right to left. When the current passes through these electronic components, a large amount of heat will be generated. In order to remove this heat, a heat sink 34 is provided between the field effect transistors 35.

[0050] Please refer to Figure 2 , Figures 4 to 8 During the operation of the angle grinder 100, the air duct system 200 operates in coordination. The air duct system 200 is defined as including the main housing 11, the motor assembly 2, and the air duct mechanism 4. The air duct mechanism 4 is described below. A drive fan 41 is provided in the first chamber 131 within the gearbox 13. The rotation of the rotor 22 causes the drive fan 41 to rotate accordingly, drawing in cooling gas 45 from the outside of the housing 1 through the air inlet 121. It is worth noting that the cooling gas 45 drawn into the housing 1 may carry dust 46 generated by the angle grinder 100. When the cooling gas 45 dissipates heat from the control assembly 3 and the motor assembly 2, the dust 46 can easily enter the coil 212 and the air gap 24, thereby damaging the motor assembly 2. Therefore, in this embodiment, the air duct mechanism 4 is equipped with a guide 43 to prevent the above phenomenon.

[0051] The flow guide 43 is constructed in a fan-like structure, with its main shape defined by a hub 431, annular slope 432, and retaining ring 433. The hub 431 is cylindrical, with a flat hub protrusion 431a on its left end face, through which a hub center hole 431b is passed. The annular slope 432 is an arc-shaped surface extending radially outward from the circumference of the hub 431, and the retaining ring 433 extends to the left from the end of the annular slope 432. Furthermore, the flow guide 43 has a combined blade 435 that evenly divides the circumference of the annular slope 432 and the circumference of the retaining ring 433. The combined blade 435 has a root 435a extending radially outward from the circumference of the annular slope 432, a first blade 435b extending from the root 435a off-axis and in an arc-shaped bend, and a second blade 435b extending axially and perpendicular to the annular slope 432 and the retaining ring 433. The guide vane 435c has two blades, and both the first blade 435b and the second blade 435c are attached to the circumferential surface of the annular slope 432 and the circumferential surface of the retaining ring 433. In terms of radial direction, both the first blade 435b and the second blade 435c have extensions that extend beyond the retaining ring 433. To increase the balance of the guide vane 43 during installation, a blade rib 435d is added to the circumferential surface of the retaining ring 433 between the first blade 435b and the second blade 435c. The radial outer end face of the blade rib 435d, the radial outer end face of the first blade 435b, and the radial outer end face of the second blade 435c are located on the same circumference. In addition to the blade rib 435d, the guide vane 43 has a counterweight ridge 434 on the outer circumferential surface of the hub 431, so as to achieve the internal and external double balance of the hub 431 and the combined blades 435 in the guide vane 43.

[0052] When installing the guide member 43, first align the rotation center of the guide member 43 with the rotation center of the rotor 22. Then, place the third bearing 436 inside the hub center hole 431b. It should be noted that the guide member 43 is rotatable relative to the third bearing 436. Next, install the third bearing 436 onto the boss 314 and abut it against the flange 313. Finally, drive the fastening screw into the threaded hole 314a. It is important to note that the diameter of the hub center hole 431b should be larger than the outer diameter of the flange 313, and the outer diameter of the hub 431 should be smaller than the inner diameter of the recess 312. The right end face of the hub 431 does not fit into the recess 312, but partially enters the space where the recess 312 is located. The purpose of this arrangement is to ensure that the rotation of the guide 43 is not interfered with by the encapsulation box 31. In addition to the interference of the encapsulation box 31 on the operation of the guide 43, the wire 215 led out from the stator 21 will also interfere with the guide 43. Therefore, the guide mechanism 115 and the limiting mechanism 116 are combined to form a receiving cavity 117 to receive the wire 215 and restrict the movement of the wire 215, which can effectively prevent the wire 215 from crossing the guide 43 due to loosening.

[0053] After entering the angle grinder 100, the cooling gas 45 first carries the dust 46 through the rear cover air duct 441 and passes through the control component 3, thereby removing the heat accumulated on the radiator 34. When flowing through the guide member 43, since the surface area of ​​the first blade 435b is larger than that of the second blade 435c, most of the cooling gas 45 acts on the first blade 435b, thereby driving the rotation of the guide member 43. In other words, the first blade 435b is the force-bearing end of the cooling gas 45 driving the rotation of the guide member 43.

[0054] Due to the cooperation between the guide element 43 and the grille 114, the space inside the main housing 11 for the flow of cooling gas 45 is divided into a first air duct 442 and a second air duct 443. The first air duct 442 and the second air duct 443 are also components of the air duct mechanism 4. The construction of the first air duct 442 and the second air duct 443 will be described below; please refer to Figure 2 and Figure 8 As shown, the first air duct 442 is the space formed between the outer wall of the stator 21, the outer wall of the grille outer ring base 114h, and the mounting wall 113, and the ventilation gap 114f is the inlet of the first air duct 442; the second air duct 443 is the internal space formed by the grille 114 and the guide member 43. Specifically, the baffle ring 433 on the guide member 43 and the grille outer ring 114b form a labyrinth channel 443a, which is the inlet section of the second air duct 443. The grille window 114e and the labyrinth channel 443a are connected, that is, the grille window 114e and the labyrinth channel 443a together form the second air duct 443.

[0055] While the cooling gas 45 drives the guide vane 43 to rotate, the second blade 435c strikes the dust 46 entrained in the cooling gas 45. Under the action of centrifugal force and striking force, the dust 46 is thrown into the first air duct 442. That is to say, the second blade 435c is the force-applying end of the guide vane 43 that throws the dust 452. At the same time, the cooling gas 45 continues to flow in the main housing 11 under the guidance of the first blade 435b, the second blade 435c, the annular slope 432 and the baffle ring 433. During this process, the cooling gas 45 is divided into two airflows: a first branch airflow 451 flowing in the first air duct 442 and a second branch airflow 452 flowing in the second air duct 443. The first branch airflow 451 carries away the dust 46 within the first air duct 442 and, guided by the air guide shroud 42, flows out from the air outlet 134. The second branch airflow 452 enters through the labyrinthine channel 443a and then flows through the grille window 114e towards the motor assembly 2. Due to the labyrinthine channel... The opening of 443a is relatively small, and the airflow of the first branch airflow 451 is greater than that of the second branch airflow 452, further preventing dust 46 from entering the second air duct 443. After leaving the second air duct 443, the second branch airflow 452 flows in two directions within the motor assembly 2. Specifically, the first direction is the space formed by the cover plate vent 214d, the end plate gap 213e, and the receiving hole 211a on the stator core 211, where a portion of the second branch airflow 452 dissipates heat from the coil 212. The second direction is the space formed by the cover plate center hole 214e, the end plate center hole 213f, and the air gap 24, where another portion of the second branch airflow 452 dissipates heat from the rotor 22 and the stator 21. Finally, the second branch airflow 452 flows out of the motor assembly 2 and merges with the first branch airflow 451, eventually being discharged together from the outlet 134. Thanks to the presence of the first air duct 442 and the second air duct 443, the motor assembly 2 possesses both excellent heat dissipation and dust prevention performance.

[0056] In this embodiment, a labyrinth structure is also formed between the inner ring 114a of the grille and the hub protrusion 431a. Even if the second branch airflow 452 carries dust 46, the dust 46 will be blocked and cannot enter the inner ring 114a of the grille through the center hole 114g of the grille to damage the second bearing 224. Furthermore, even if the dust 46 enters the grille window 114e with the second branch airflow 452, since the dustproof component 23 rotates with the rotor shaft 221, the dust 46 will be flung away when it comes into contact with the dustproof component 23 and will not flow into the air gap 24 under the action of the second branch airflow 452.

[0057] This invention is not limited to the specific embodiments described above. Those skilled in the art will readily understand that many alternative solutions exist for the air duct system and power tool of this invention without departing from the principles and scope of the invention. The scope of protection of this invention is defined by the claims.

Claims

1. A duct system comprising a housing and a duct mechanism for cooling a motor assembly housed within the housing, the motor assembly having a stator fixed to the housing and a rotor passing through the stator, the duct mechanism having a drive fan mounted on the rotor, the drive fan rotating to generate cooling gas; characterized in that: The air duct mechanism includes a guide member driven to rotate by the cooling gas, a first air duct formed between the stator and the housing, and a second air duct independent of the first air duct, the second air duct being at least partially located downstream of the guide member; the cooling gas flows through the first air duct and the second air duct, and dust entrained in the cooling gas is guided into the first air duct by the guide member; the housing has a grid supporting the rotor, the grid being connected to the inner wall of the housing, and the guide member and the grid surrounding to form the second air duct; the second air duct includes a labyrinthine channel and a grid vent, the grid vent... The window and the labyrinthine passage are connected, and the grille window extends along the axial direction of the grille; the grille includes an inner ring and an outer ring connected to the inner ring, and the grille window is located between the inner ring and the outer ring; the guide has a baffle that covers at least a portion of the outer ring, and the labyrinthine passage is located between the baffle and the outer ring; the guide has a first blade that extends in an arc shape off-axis and a second blade that extends axially, the first blade being the force-receiving end of the cooling gas driving the guide to rotate, and the second blade being the force-applying end of the guide throwing the dust.

2. The air duct system according to claim 1, characterized in that: The rotor is supported on the grid by a second bearing, and the first air duct is formed between the outer wall of the grid, the outer wall of the stator, and the inner wall of the housing.

3. The air duct system according to claim 2, characterized in that: The airflow guide includes a hub, a ring slope extending from the hub, a retaining ring connected to the ring slope, and the labyrinthine channel is the inlet section of the second air duct.

4. The air duct system according to claim 3, characterized in that: The guide member is provided with a combined blade on the surface of the ring slope. The combined blade includes a first blade and a second blade. The first blade is connected to the root of the ring slope, and the surface area of ​​the first blade is larger than the surface area of ​​the second blade.

5. The air duct system according to claim 1, characterized in that: The rotation center of the guide element coincides with the rotation center of the rotor.

6. The air duct system according to claim 1, characterized in that: The stator has a stator core, an end plate abutting against the end face of the stator core, and a cover plate abutting against the end face of the end plate. The outer ring of the grille abuts against the end face of the cover plate. The end plate forms an end plate gap. The cover plate has a cover plate vent. The grille vent, the cover plate vent, and the end plate gap are connected.

7. A power tool, comprising a housing, a motor assembly housed within the housing, a control assembly for driving the motor assembly, and a cooling duct mechanism for cooling the motor assembly and the control assembly, the housing and the cooling duct mechanism forming a cooling duct system; characterized in that: The air duct system is the air duct system according to any one of claims 1-6; the control component has an encapsulation box connected to the housing, and the air guide is installed on the end face of the encapsulation box facing the motor assembly.

8. The power tool according to claim 7, characterized in that: The power tool mentioned is an angle grinder.

Images