Fan assembly and electric tool

Abstract

The utility model discloses a fan assembly and an electric tool, the fan assembly comprises a driving shaft and a centrifugal wind wheel, the centrifugal wind wheel is coaxially connected with the driving shaft and can rotate towards a first direction under the driving of the driving shaft, and the centrifugal wind wheel comprises a plurality of blades distributed at intervals along the circumferential direction. Each blade extends from the inner circumference of the centrifugal wind wheel to the outer circumference of the centrifugal wind wheel and is provided with an air inlet end relatively close to the driving shaft and an air outlet end relatively far away from the driving shaft, and each blade is at least partially bent in the direction opposite to the first direction from the air inlet end to the air outlet end. According to the utility model, as the blades are bent along the direction opposite to the rotating direction, airflow can flow from the air inlet end to the air outlet end more smoothly under the guidance of the blades, so that the friction frequency between the blades and air is effectively reduced, the probability of occurrence of high-frequency squeal sound is reduced, and the use experience of operators is improved. And meanwhile, smoother air outlet is beneficial to improving the heat dissipation efficiency of the fan assembly.

Description

Technical Field

[0001] This utility model relates to the field of power tool technology, specifically to a fan assembly and a power tool. Background Technology

[0002] Power tools are widely used in modern industry and daily life. As the performance of power tools continues to improve, motor speeds are also increasing. For example, the motor speed of a diamond drilling machine can reach 25,000 rpm. While high speeds bring powerful working efficiency, they also present the problem of motor heat dissipation. To solve this problem, incorporating fan assemblies into power tools has become a common solution. These fan assemblies use forced airflow to remove the heat generated by the motor, ensuring stable operation within a suitable temperature range and preventing performance degradation, shortened lifespan, or even damage due to overheating.

[0003] The applicant discovered that the blade structure used in existing wind turbine components has significant defects in practical applications. Specifically, when the wind turbine rotates, the contact area and friction frequency between the blades and the air are high. Each rotation of the blades generates intense friction with the surrounding air, leading to high-frequency vibrations and producing a high-frequency whistling sound. This piercing sound not only causes discomfort to the operator's hearing but also reflects the low efficiency of the wind turbine components, as some energy is consumed in generating noise rather than being effectively used to propel airflow for heat dissipation. Utility Model Content

[0004] The present invention aims to provide a fan assembly and power tool that can reduce the probability of high-frequency whistling noise when the fan assembly is rotating to dissipate heat, thereby improving the user experience.

[0005] To solve the above-mentioned technical problems, this utility model provides a fan assembly, comprising:

[0006] drive shaft; and,

[0007] A centrifugal impeller is coaxially connected to the drive shaft and can rotate in a first direction under the drive of the drive shaft. The centrifugal impeller includes a plurality of blades spaced apart circumferentially. Each blade extends from the inner circumference to the outer circumference of the centrifugal impeller. Each blade has an air inlet end relatively close to the drive shaft and an air outlet end relatively far from the drive shaft. Each blade is at least partially bent in a direction opposite to the first direction from the air inlet end to the air outlet end.

[0008] Optionally, in each of the blades, the angle between the line L1 connecting the air inlet end and the air outlet end and the diameter extension line L2 passing through the air inlet end is α, where α is greater than or equal to 16 degrees and less than or equal to 24 degrees.

[0009] Optionally, the centrifugal impeller further includes a chassis, the drive shaft passing through the chassis, a plurality of blades disposed on one side of the chassis, and the air outlet ends of the plurality of blades extending radially beyond the outer periphery of the chassis; and / or,

[0010] The centrifugal impeller has 20 or fewer blades.

[0011] Optionally, the fan assembly further includes an air guide ring, which is coaxial with and arranged side by side with the centrifugal impeller and located on the air inlet side of the centrifugal impeller. An air inlet is provided on the air guide ring, and the diameter of the air inlet is smaller than the outer diameter of the centrifugal impeller.

[0012] Optionally, each of the blades has a first segment and a second segment arranged sequentially from the inner circumference to the outer circumference. In a projection view along the axial direction, each first segment is located inside the air inlet, and each second segment is located outside the air inlet; wherein,

[0013] The axial dimensions of each of the first segments gradually increase from the inner circumference to the outer circumference; and / or,

[0014] In each of the blades, at least the second segment bends from the inner periphery to the outer periphery in a direction opposite to the first direction.

[0015] Optionally, the air guide ring includes an air outlet ring, which has an air inlet that is axially away from the centrifugal impeller and an air outlet that is axially close to the centrifugal impeller. The inner diameter of the air outlet ring gradually increases from the air inlet to the air outlet, and an air guide gap is defined between the inner side of the air outlet ring and the air inlet side of the centrifugal impeller.

[0016] Optionally, the axial dimensions of each of the second segments gradually decrease from the inner circumference to the outer circumference, so that the air guide gap extends obliquely from the inner circumference to the outer circumference towards the centrifugal impeller; and / or,

[0017] The air guide ring also includes an air inlet ring, which protrudes from the side of the air outlet ring facing away from the centrifugal impeller and is arranged around the outer periphery of the air inlet. The inner diameter of the air inlet ring is larger than that of the air inlet and smaller than that of the air outlet.

[0018] To solve the above-mentioned technical problems, this utility model provides an electric tool, comprising:

[0019] A housing, wherein an installation cavity is formed within the housing;

[0020] The output shaft is rotatably mounted on the housing;

[0021] As described above, the fan assembly is disposed within the mounting cavity; and...

[0022] A motor is disposed within the mounting cavity. The motor shaft of the motor constitutes the drive shaft of the fan assembly. Alternatively, the motor is driven by the drive shaft of the centrifugal impeller through a transmission mechanism, and the drive shaft is driven by the output shaft.

[0023] Optionally, the fan assembly further includes an air guide ring, which is coaxial with and arranged side by side with the centrifugal impeller, and is located on the air inlet side of the centrifugal impeller;

[0024] The air guide ring divides the mounting cavity into an air inlet cavity and an air outlet cavity arranged sequentially along the axial direction. The rotor of the motor is installed in the air inlet cavity, and the centrifugal impeller is installed in the air outlet cavity. An air passage gap is defined between the outer periphery of the air guide ring and the inner side of the housing.

[0025] Optionally, the housing includes a first housing, a second housing, and a third housing that are detachably connected in sequence along the axial direction. The air guide ring is press-fitted onto the first housing, and the output shaft is installed on the third housing. The first housing and the air guide ring form the air inlet cavity, and the second housing and the air guide ring form the air outlet cavity. The second housing has a housing air outlet that is radially spaced from the blades.

[0026] The technical solution provided by this utility model has the following advantages:

[0027] The fan assembly provided by this utility model includes a drive shaft and a centrifugal impeller. The centrifugal impeller is coaxially connected to the drive shaft and can rotate in a first direction under the drive of the drive shaft. The centrifugal impeller includes a plurality of blades spaced apart circumferentially. Each blade extends from the inner circumference to the outer circumference of the centrifugal impeller and has an air inlet end relatively close to the drive shaft and an air outlet end relatively far from the drive shaft. Each blade is at least partially bent in a direction opposite to the first direction from the air inlet end to the air outlet end.

[0028] In the embodiments provided by this utility model, when the drive shaft drives the centrifugal impeller to rotate, the airflow, guided by the blades in the opposite direction to the rotation direction of the drive shaft, can flow more smoothly from the inlet to the outlet, achieving radial airflow. Compared with traditional impeller blades, the reverse-bent blades effectively reduce the friction frequency between the blades and the air, reducing high-frequency vibrations caused by friction, thereby reducing the probability of high-frequency whistling sounds and improving the user experience for operators. Simultaneously, smoother airflow helps improve the heat dissipation efficiency of the fan components. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 A three-dimensional structural diagram of an embodiment of the power tool provided by this utility model;

[0031] Figure 2 for Figure 1 A partial three-dimensional structural diagram of a Chinese power tool;

[0032] Figure 3 for Figure 1 Assembly diagram of the second housing and the fan assembly;

[0033] Figure 4 for Figure 3 Cross-sectional view of the second housing and the fan assembly;

[0034] Figure 5 for Figure 4 Exploded view of the three-dimensional structure of the wind turbine components;

[0035] Figure 6 for Figure 5 A three-dimensional structural diagram of a centrifugal fan.

[0036] Figure 7 for Figure 6 A front view of the centrifugal impeller along the axial direction;

[0037] Figure 8 for Figure 5 A three-dimensional structural diagram of the central air guide ring;

[0038] Figure 9 for Figure 8 A three-dimensional structural diagram of the central wind guide ring from another perspective.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1-Power tool; 100-Fan assembly; 10-Centrifugal impeller; 11-Blade; 111-Air inlet; 112-Air outlet; 113-First section; 114-Second section; 12-Chassis; 20-Air guide ring; 21-Air inlet; 22-Air outlet; 23-Air inlet ring; 24-Air outlet ring; 25-Air guide gap; 26-Air passage gap; 30-Drive shaft; 200-Housing; 201-Mounting cavity; 2011-Air inlet cavity; 2012-Air outlet cavity; 202-First housing; 203-Second housing; 204-Third housing; 205-Housing outlet; 206-Housing inlet; 300-Output shaft; 400-Motor; 401-Rotor. Detailed Implementation

[0041] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. The present utility model will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this utility model can be combined with each other.

[0042] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0043] Please see Figures 1 to 9 This utility model provides a fan assembly 100 and an electric tool 1 including the fan assembly 1.

[0044] Please see Figure 1 and Figure 2 The power tool 1 includes a housing 200, an output shaft 300, a motor 400, and a fan assembly 100. The housing 200 contains a mounting cavity 201, providing mounting space and protection for the various components. The material of the housing 200 can be selected as needed; however, the housing 200 should be lightweight, have good insulation properties, and strong impact resistance, and is preferably made of high-strength engineering plastics.

[0045] The output shaft 300 is rotatably mounted on the housing 200 and operates on the target workpiece under the drive of the motor 400 located in the mounting cavity 201. The structure and operation of the output shaft 300 depend on the type of power tool 1. Taking an electric drilling machine as an example, the output shaft 300 transmits the torque output by the motor 400 to drive the drill bit to rotate and perform the drilling operation. The motor 400 and the output shaft 300 can be coaxially arranged or connected by a transmission mechanism instead of being coaxially arranged.

[0046] In this embodiment, the motor 400 is preferably a high-speed motor 400, which has high heat dissipation requirements. For details, please refer to the following references. Figures 3 to 5 The mounting cavity 201 is also equipped with a fan assembly 100, which includes a drive shaft 30 and a centrifugal impeller 10. The drive shaft 30 drives the centrifugal impeller 10 to rotate, thereby driving airflow to flow in the mounting cavity 201 and through the motor 400 to achieve heat dissipation of the motor 400.

[0047] Optionally, the motor shaft of the motor 400 constitutes the drive shaft 30 of the fan assembly 100, meaning the motor shaft directly drives the centrifugal impeller 10 to rotate. Alternatively, the motor 400 can be connected to the drive shaft 30 of the fan via a transmission mechanism to drive the centrifugal impeller 10 to rotate. In this embodiment, it is preferable to use the method of directly driving the centrifugal impeller 10 to rotate the centrifugal impeller 10 to achieve high-speed rotation of the centrifugal impeller 10. This method is simple and reliable, and also achieves efficient heat dissipation of the motor 400 while it is working.

[0048] In this embodiment, the centrifugal impeller 10 and the drive shaft 30 are coaxially connected, and this coaxial connection can be achieved in several ways. Specifically, the centrifugal impeller 10 and the drive shaft 30 can be integrally formed. Alternatively, the centrifugal impeller 10 can have a shaft hole in its center, and the drive shaft 30 can be coaxially connected and fixed to the centrifugal impeller 10 by welding or interference fit. Another option is that the centrifugal impeller 10 and the drive shaft 30 can be circumferentially fixedly connected by a key or other means.

[0049] Please continue reading. Figure 6 and Figure 7 The centrifugal impeller 10 can rotate in a first direction under the drive of the drive shaft 30. The centrifugal impeller 10 includes a plurality of blades 11 distributed circumferentially, each blade 11 extending from the inner circumference to the outer circumference of the centrifugal impeller 10. Each blade 11 has an air inlet end 111 relatively close to the drive shaft 30 and an air outlet end 112 relatively far from the drive shaft 30. Each blade 11 is at least partially bent in a direction opposite to the first direction from the air inlet end 111 to the air outlet end 112.

[0050] In this embodiment, when the drive shaft 30 drives the centrifugal impeller 10 to rotate, the blades 11 rotate in the same direction as the drive shaft 30 (e.g., along the rotation direction of the drive shaft 30). Figure 7 The first direction in the middle) the opposite direction (e.g.) Figure 7 The second direction of the bend makes the air flow on the surface of the blade 11 smoother. Under the guidance of the blade 11, the airflow can flow more smoothly from the air inlet 111 to the air outlet 112, realizing axial air inlet and radial air outlet.

[0051] Compared to traditional wind turbine blades, the reverse-curved blades 11 effectively reduce the friction frequency between the blades 11 and the air, reducing friction and turbulence between the air and the blades 11, and decreasing high-frequency vibrations caused by friction between the blades 11 and the air. This reduces the probability of high-frequency whistling sounds and improves the user experience for operators. Simultaneously, smoother airflow improves the heat dissipation efficiency of the fan assembly 100.

[0052] The degree of curvature of blade 11 can be set as needed. Generally speaking, such as... Figure 7 As shown, the angle between the line L1 connecting the air inlet end 111 and the air outlet end 112 of each blade 11 and the diameter extension line L2 passing through the air inlet end 111 is α, where α is greater than or equal to 16 degrees and less than or equal to 24 degrees.

[0053] The applicant discovered that when the blade 11 is excessively curved, the airflow is significantly reduced, adversely affecting the working efficiency of the fan assembly 100. Conversely, when the blade 11 is too slightly curved, the effect of reducing high-frequency vibration caused by friction between the blade 11 and the air is not significant, and high-frequency whistling noise still occurs during operation. Therefore, the curvature of the blade 11 needs to be designed according to the size of the power tool 1 itself and the specific airflow and air pressure requirements of different types of power tools 1. The applicant found that if α is greater than or equal to 16 degrees and less than or equal to 24 degrees, within this range, the airflow of the fan assembly 100 during operation can meet the heat dissipation requirements of the motor 400, while significantly reducing the high-frequency vibration caused by friction between the blade 11 and the air, reducing or even eliminating the probability of high-frequency whistling noise, and improving the user experience for operators.

[0054] Alternatively, please continue reading Figure 6 and Figure 7 The centrifugal impeller 10 also includes a chassis 12, with a drive shaft 30 passing through the chassis 12. Multiple blades 11 are disposed on one side of the chassis 12, and the outlet ends 112 of the blades 11 extend radially beyond the outer periphery of the chassis 12. The chassis 12 provides stable support for the blades 11, ensuring that the blades 11 do not deform due to rotation when the centrifugal impeller 10 rotates at high speed, thus preventing performance degradation. Simultaneously, the chassis 12 acts to block the axial flow of air, ensuring that airflow towards the centrifugal impeller 10 enters axially and exits radially outwards.

[0055] The design of the air outlets 112 of each blade 11 extending beyond the outer periphery of the chassis 12 effectively increases the exhaust space near the air outlets 112, preventing situations where the space at the air outlets 112 of each blade is too small, leading to increased local airflow compression and turbulence, and hindering smooth airflow. In other words, the design of multiple blades 11 extending radially beyond the outer periphery of the chassis 12 helps to increase the exhaust volume, while also reducing the high-frequency vibration caused by friction between the air outlets 112 of the blades and the air, reducing or even eliminating the probability of high-frequency whistling noise, and improving the user experience for operators.

[0056] The applicant discovered that the number of blades 11 also significantly affects the generation of high-frequency whistling noise. When there are too many blades 11, the frequency of friction between the blades 11 and the air is too high, easily generating high-frequency whistling noise. With the motor speed remaining constant at 400 rpm, reducing the number of blades 11 can significantly reduce the frequency of friction between the blades 11 and the air. In this example, it is preferable that the number of blades 11 of the centrifugal impeller 10 is less than or equal to 20, thereby reducing the phenomenon of high-frequency vibration generated by friction between the air outlet end 112 of the blades 11 and the air, reducing or even eliminating the probability of high-frequency whistling noise, and improving the user experience for operators.

[0057] Based on any of the above embodiments, please refer to the following: Figures 1 to 4 The fan assembly 100 also includes an air guide ring 20, which is coaxial with and side-by-side with the centrifugal impeller 10, and located on the air inlet side of the centrifugal impeller 10. The air guide ring 20 divides the mounting cavity 201 into an air inlet cavity 2011 and an air outlet cavity 2012 arranged sequentially along the axial direction. The rotor 401 of the motor 400 is installed in the air inlet cavity 2011, and the centrifugal impeller 10 is installed in the air outlet cavity 2012. The housing 200 is also provided with a housing air inlet 206 and a housing air outlet 205. The housing air inlet 206 is directly connected to the air inlet cavity 2011, and the housing air outlet 205 is directly connected to the air outlet cavity 2012. In other words, external air flows into the air inlet 2011 from the air inlet 206 of the housing, and after being cooled by the motor 400, it flows axially into the air outlet 2012 under the guidance of the air guide ring 20, flows to the center of the centrifugal impeller 10, and then flows radially towards the air outlet 205 of the housing under the drive of the centrifugal impeller 10, towards the outside of the housing 200.

[0058] Please continue to refer to the following: Figure 8 and Figure 9The air guide ring 20 has an air inlet 21, the diameter of which is smaller than the outer diameter of the centrifugal impeller 10, serving a concentrating function. In other words, the main function of the air guide ring 20 is to guide air into the centrifugal impeller 10 more concentratedly, improving air intake efficiency and compensating for airflow loss caused by the design of the impeller structure and number. Specifically, because the diameter of the air inlet 21 is smaller than the outer diameter of the centrifugal impeller 10, the air accelerates upon entering the impeller, creating a negative pressure zone that attracts more air, thereby increasing the airflow and effectively enhancing heat dissipation. Simultaneously, the air guide ring 20 also plays a role in rectifying airflow, reducing air turbulence and further lowering noise levels. In different types of power tools 1, the size, shape, and material of the air guide ring 20 can be adjusted according to actual needs. For some power tools 1 with extremely high noise requirements, such as small electric drills used for electronic equipment repair, the air guide ring 20 can be made of sound-absorbing materials, such as polyurethane foam, to absorb some noise while guiding air. For power tools 1 that work in harsh environments, such as electric rock drills for mining, the air guide ring 20 can be made of more wear-resistant and corrosion-resistant metal materials, such as stainless steel, to adapt to high-intensity working environments.

[0059] Preferably, please refer to the following: Figures 5 to 7 Each blade 11 has a first segment 113 and a second segment 114 arranged sequentially from the inner circumference to the outer circumference. In the axial projection view, each first segment 113 is located inside the air inlet 21, and each second segment 114 is located outside the air inlet 21. Optionally, the axial dimension of each first segment 113 gradually increases from the inner circumference to the outer circumference, and / or, in each blade 11, at least the second segment 114 is bent from the inner circumference to the outer circumference in a direction opposite to the first direction.

[0060] In this embodiment, the segmented design of the blades 11 better adapts to the airflow characteristics in different areas. During fan operation, the gradually increasing axial dimension of the first segment 113 of the blades 11 within the air inlet 21 helps guide air smoothly into the channel between the blades 11, reducing air impact and turbulence. When air enters the second segment 114 of the blades 11, the reverse-bending design of the second segment 114 further guides the air, allowing it to be ejected more efficiently under centrifugal force. From an energy conversion perspective, this design enables the fan assembly 100 to more effectively convert the mechanical energy of the motor 400 into the kinetic energy of the air, improving the fan's efficiency. Simultaneously, the reverse-bending blade structure also reduces high-frequency vibrations caused by friction between the second segment 114 of the blades 11 and the air, reducing or even eliminating the probability of high-frequency whistling noise and improving the operator's experience.

[0061] Preferably, such as Figure 2As shown, an air passage gap 26 is formed between the outer periphery of the air guide ring 20 and the inner side of the casing 200. This means that more airflow space is provided at the outlet end 112 of each blade 11, preventing insufficient space at the outlet end 112 of each blade 11, which could lead to increased local airflow compression and turbulence, hindering smooth airflow. This design not only improves exhaust volume but also reduces high-frequency vibrations caused by friction between the outlet end 112 of the blades 11 and the air, lowering or even eliminating the probability of high-frequency whistling noise and improving the operator's experience. The air passage gap 26 extends circumferentially, guiding airflow more evenly, resulting in smoother airflow and lower noise.

[0062] Please continue reading. Figure 4 In one embodiment, the air guide ring 20 includes an air outlet ring 24. The air outlet ring 24 has an air inlet 21 that is axially away from the centrifugal impeller 10 and an air outlet 22 that is axially closer to the centrifugal impeller 10. The inner diameter of the air outlet ring 24 gradually increases from the air inlet 21 to the air outlet 22. An air guide gap 25 is defined between the inner side of the air outlet ring 24 and the air inlet side of the centrifugal impeller 10. The existence of the air guide gap 25 ensures that air can flow smoothly between the air outlet ring 24 and the centrifugal impeller 10, avoiding air blockage due to the air guide gap 25 being too small, or a reduction in fan airflow due to the air guide gap 25 being too large. The gradually expanding structure of the air outlet ring 24 plays an important role in the airflow process. It can cause the air velocity to gradually decrease, thereby increasing the wind pressure, which is beneficial to improving the working efficiency of the fan assembly 100.

[0063] For further recommendations, please refer to the following: Figure 6 and Figure 7 As mentioned earlier, each blade 11 has a first segment 113 and a second segment 114 arranged sequentially from the inner circumference to the outer circumference. Each second segment 114 is located outside the air inlet 21, that is, each second segment 114 is arranged opposite to the inner side of the air outlet ring 24. In this embodiment, the axial dimensions of each second segment 114 gradually decrease from the inner circumference to the outer circumference, and the shape of the air outlet ring 24 is correspondingly changed so that the air guide gap 25 extends obliquely from the inner circumference to the outer circumference towards the centrifugal impeller 10. This design allows the airflow to be guided more smoothly to the air outlet 205 of the housing along the air guide gap 25, improving the air delivery efficiency of the fan assembly 100 while also providing a larger airflow space, avoiding air blockage due to insufficient air outlet space and increased friction between the air and the blades 11.

[0064] Optionally, the air guide ring 20 also includes an air inlet ring 23, which protrudes from the air outlet ring 24 on the side facing away from the centrifugal impeller 10 and is arranged around the outer periphery of the air inlet 21. The inner diameter of the air inlet ring 23 is larger than that of the air inlet 21 and smaller than that of the air outlet 22. The design of the air inlet ring 23 further optimizes the path of air entering the air guide ring 20. When the fan assembly 100 is working, the air inlet ring 23 can guide the outside air to converge more smoothly into the air inlet 21, reducing the resistance when the air enters. While guiding the air, the air inlet ring 23 can also play a certain pre-acceleration role, making the speed of the air entering the air inlet 21 more uniform. This not only improves the air intake efficiency, but also improves the air flow state in the centrifugal impeller 10, thereby improving the overall performance of the fan assembly 100. In different power tools 1, the size and other parameters of the air inlet ring 23 can be adjusted according to the structure and performance requirements of the power tool 1 to maximize the air intake efficiency.

[0065] Based on the above embodiments, please continue to refer to... Figure 1 and Figure 2 The housing 200 includes a first housing 202, a second housing 203, and a third housing 204 that are detachably connected sequentially along the axial direction. A guide ring 20 is press-fitted onto the first housing 202, and an output shaft 300 is mounted on the third housing 204. The first housing 202 and the guide ring 20 enclose an air inlet chamber 2011, and the second housing 203 and the guide ring 20 enclose an air outlet chamber 2012. The second housing 203 has a housing outlet 205 that is radially spaced from the blades 11. The radially spaced housing outlet 205 on the second housing 203 avoids interference from the airflow generated by the rotation of the blades 11, ensuring smooth air discharge. Preferably, the drive shaft 30 is rotatably supported in the second housing 203 by a bearing seat located within the second housing 203, with one end extending into the third housing 204 and connected to the output shaft 300, and the other end extending into the first housing 202. During the production process, the first housing 202, the second housing 203, and the third housing 204 can be processed and pre-treated separately before assembly, improving production efficiency. During use, if the fan assembly 100 or other components malfunction, the user or maintenance personnel can easily disassemble the corresponding first housing 202, second housing 203, and / or third housing 204 for repair or replacement.

[0066] Obviously, the embodiments described above are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, those skilled in the art can make other variations or modifications without creative effort, and all such variations or modifications should fall within the protection scope of this utility model.

Claims

1. A fan assembly comprising: Comprising: a drive shaft; and, a centrifugal fan wheel coaxially connected with the drive shaft and rotatable in a first direction under the drive of the drive shaft, the centrifugal fan wheel comprising a plurality of circumferentially spaced blades, each of the blades extending from an inner circumference to an outer circumference of the centrifugal fan wheel, each of the blades having an air inlet end relatively close to the drive shaft and an air outlet end relatively far away from the drive shaft, each of the blades being at least partially curved from the air inlet end to the air outlet end in a direction opposite to the first direction.

2. The fan assembly of claim 1, wherein, In each of the blades, an included angle between a line L1 connecting the air inlet end and the air outlet end and a diameter extension line L2 passing through the air inlet end is a, a being greater than or equal to 16 degrees and less than or equal to 24 degrees.

3. The fan assembly of claim 1, wherein, The centrifugal fan wheel further comprises a base plate, the drive shaft being arranged in the base plate, the plurality of blades being arranged on one side of the base plate, the air outlet ends of the plurality of blades extending radially beyond an outer circumference of the base plate; and / or, The number of the blades of the centrifugal fan wheel is less than or equal to 20.

4. The fan assembly of any one of claims 1 to 3, wherein, The fan assembly further comprises a wind guide ring, the wind guide ring being coaxial with and arranged side by side with the centrifugal fan wheel and located on an air inlet side of the centrifugal fan wheel, the wind guide ring being provided with an air inlet opening, a diameter of the air inlet opening being less than an outer diameter of the centrifugal fan wheel.

5. The fan assembly of claim 4, wherein, Each of the blades has a first section and a second section arranged in sequence from the inner circumference to the outer circumference, each of the first sections being located within the air inlet opening and each of the second sections being located outside the air inlet opening in an axial projection view; wherein, The size of each of the first sections in the axial direction gradually increases from the inner circumference to the outer circumference; and / or, In each of the blades, at least the second section is curved from the inner circumference to the outer circumference in a direction opposite to the first direction.

6. The fan assembly of claim 5, wherein, The wind guide ring comprises an air outlet ring having an air outlet opening relatively far away from the air inlet opening of the centrifugal fan wheel in the axial direction and an air inlet opening relatively close to the centrifugal fan wheel in the axial direction, an inner diameter of the air outlet ring gradually increasing from the air inlet opening to the air outlet opening, a gap between an inner side of the air outlet ring and the air inlet side of the centrifugal fan wheel defining a wind guide gap.

7. The fan assembly of claim 6, wherein, The size of each of the second sections in the axial direction gradually decreases from the inner circumference to the outer circumference, so that the wind guide gap extends in a direction close to the centrifugal fan wheel from the inner circumference to the outer circumference; and / or, The wind guide ring further comprises an air inlet ring, the air inlet ring being convexly arranged on a side of the air outlet ring away from the centrifugal fan wheel and annularly arranged on an outer circumference of the air inlet opening, an inner diameter of the air inlet ring being greater than the air inlet opening and less than the air outlet opening.

8. A power tool characterized by comprising: Comprising: a housing, an installation cavity being formed in the housing; an output shaft rotatably mounted in the housing; the fan assembly according to any one of claims 1 to 7, the fan assembly being arranged in the installation cavity; and, a motor arranged in the installation cavity, a motor shaft of the motor constituting a drive shaft of the fan assembly, or the motor being in transmission connection with the drive shaft of the centrifugal fan wheel through a transmission mechanism, the drive shaft being in transmission connection with the output shaft.

9. The power tool of claim 8, wherein, The fan assembly further comprises a wind guide ring coaxial with and parallel to the centrifugal fan wheel and located at the air inlet side of the centrifugal fan wheel; The wind guide ring divides the mounting cavity into an air inlet cavity and an air outlet cavity arranged in sequence along the axial direction, the rotor of the motor is mounted in the air inlet cavity, the centrifugal fan wheel is mounted in the air outlet cavity, and an air passing gap is defined between the outer periphery of the wind guide ring and the inner side of the casing.

10. The power tool of claim 9, wherein, The casing comprises a first casing, a second casing and a third casing detachably connected in sequence along the axial direction, the wind guide ring is press-fitted to the first casing, the output shaft is mounted to the third casing, the first casing and the wind guide ring enclose the air inlet cavity, the second casing and the wind guide ring enclose the air outlet cavity, and the second casing is provided with a casing air outlet opening spaced from the blades in the radial direction.

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