CN117967586A

CN117967586A - Centrifugal fan, outer rotor motor and electric tool

Info

Publication number: CN117967586A
Application number: CN202211310098.1A
Authority: CN
Inventors: 储微; 刘正伟; 卢惠
Original assignee: Positec Power Tools Suzhou Co Ltd
Current assignee: Positec Power Tools Suzhou Co Ltd
Priority date: 2022-10-25
Filing date: 2022-10-25
Publication date: 2024-05-03
Also published as: WO2024088305A1

Abstract

The invention relates to a centrifugal fan, an outer rotor motor and an electric tool, wherein in the heat dissipation process, a fixed part rotates along with the starting of a motor body to drive blades arranged circumferentially to rotate, so that heat in the motor body is driven to enter an air duct along with air flow, and the heat is discharged out of the centrifugal fan from the air duct, so that the heat dissipation of the motor body is realized. Because be provided with in the centrifugal fan and restrain the flow spare, and restrain the one end that the flow spare is located the blade subassembly and is kept away from the motor body, consequently, under the restraint of restraining the flow spare, the air current that restricts blade subassembly and is kept away from motor body one side flows in to the centrifugal fan, avoids the air current that flows back to the centrifugal fan to influence the total intake in the motor body. Through this centrifugal fan, so design, can effectively improve the air current flow direction, increase the total intake and the effective discharge of wind channel inside air current, improve air inlet efficiency to improve motor radiating efficiency.

Description

Centrifugal fan, outer rotor motor and electric tool

Technical Field

The invention relates to the technical field of heat dissipation equipment, in particular to a centrifugal fan, an outer rotor motor and an electric tool.

Background

An electric tool is a device that uses a motor as a driving source to perform hammering, screwing, suction, and the like, such as: the product performance of the screwdriver, the nailing gun, the blowing and sucking machine and the like is greatly dependent on the stable operation of the motor, which is also dependent on the heat dissipation performance of the motor.

The heat radiation structure of the motor is mainly divided into an axial flow fan and a centrifugal fan. The centrifugal fan is widely applied to an outer rotor motor by utilizing centrifugal force to radially boost axial wind and then throw the axial wind out along the circumferential direction. However, due to the defect design of the traditional centrifugal fan structure, air flow on the side of the centrifugal fan, which is opposite to the motor, can flow into the air duct from the opening on the side of the centrifugal fan, which is opposite to the motor, so that the total air inlet quantity is reduced, and the heat dissipation efficiency of the motor is weakened.

Disclosure of Invention

Based on this, it is necessary to provide a centrifugal fan, an external rotor motor and an electric tool, which can effectively improve the airflow direction, increase the effective discharge amount of the airflow in the air duct, and improve the heat dissipation efficiency of the motor.

A centrifugal fan for rotating under the drive of an outer rotor motor to radiate heat from the outer rotor motor, the centrifugal fan comprising: the fixing part is connected with the output shaft of the outer rotor motor and is used for rotating around the axis of the output shaft under the drive of the output shaft so as to drive the centrifugal fan to rotate; the blade assembly comprises a plurality of blades, the blades are arranged at intervals around the axis of the output shaft and driven by the fixing part to rotate around the axis of the output shaft, an air channel for air flow circulation is formed between two adjacent blades, and the blade assembly comprises an air inlet end facing the motor body of the outer rotor motor; the centrifugal fan further comprises a flow inhibiting piece, wherein the flow inhibiting piece is arranged on the fixing part and/or the blades and is positioned at one end of the blade assembly, which is opposite to the motor body, and the flow inhibiting piece is used for inhibiting air flow on one side of the blade assembly, which is opposite to the motor body, from flowing into the centrifugal fan.

According to the motor, in the heat dissipation process, the fixing part rotates along with the starting of the motor body to drive the blades arranged in the circumferential direction to rotate, so that heat in the motor body enters the air duct along with air flow from one side of the motor body, and the heat is discharged out of the centrifugal fan from the air duct, so that the heat dissipation of the motor body is realized. Because be provided with in the centrifugal fan and restrain the flow spare, and restrain the one end that the flow spare is located the blade subassembly and is kept away from the motor body, consequently, under the restraint of restraining the flow spare, the air current that restricts blade subassembly and is kept away from motor body one side flows in to the centrifugal fan, avoids the air current that flows back to the centrifugal fan to influence the total intake in the motor body. Through this centrifugal fan, so design, can effectively improve the air current flow direction, increase the total intake and the effective discharge of wind channel inside air current, improve air inlet efficiency to improve motor radiating efficiency.

In one embodiment, the flow inhibiting member includes a flow guiding surface disposed towards the motor body, the flow guiding surface being disposed around the axial direction of the output shaft, the flow guiding surface at least partially shielding or covering an end of the blade assembly facing away from the motor body, for enabling the partial air flow to flow out of the air duct from the radial direction along the flow guiding surface after entering the air duct from the air inlet end in the axial direction.

In one embodiment, the flow inhibiting member is disposed on the fixing portion, and a periphery of the flow inhibiting member extends out of the fixing portion along a radial direction of the output shaft, and a portion of the flow inhibiting member extending out of the fixing portion is connected to each of the blades.

In one embodiment, the flow inhibitor is a plate-like member, and a thickness of an end of the plate-like member near the output shaft is greater than a thickness of an end of the plate-like member distant from the output shaft in a radial direction of the output shaft.

In one embodiment, the thickness of the plate-like member in the radial direction of the output shaft is constant from an end close to the output shaft to an end distant from the output shaft.

In one embodiment, a circular contour is defined between one ends of the blades, which are far away from the fixing portion, the flow restraining member is configured into a circular structure, the circle center of the flow restraining member and the circle center of the circular contour are concentrically arranged, and the ratio of the diameter d1 of the outer contour of the flow restraining member to the diameter d2 of the circular contour is in the range of 0.6-1.

In one embodiment, the thickness of the blade increases in the radial direction of the output shaft from an end of the blade near the output shaft to an end of the blade away from the output shaft.

In one embodiment, the thickness of the blade ranges from 1mm to 3mm from the end of the blade near the fixing portion to the end of the blade far from the fixing portion.

In one embodiment, each blade comprises a main body and a mounting part, one end of the main body is connected with the fixing part, and one end of the main body away from the fixing part extends along one side towards the motor body to form the mounting part; the centrifugal fan further comprises a mounting ring, wherein the mounting ring is connected with the mounting part of each blade, and the mounting ring is used for being matched with the motor body so that the motor body drives the centrifugal fan to rotate.

In one embodiment, one of the mounting ring and the motor body is provided with a positioning protrusion, and the other one is provided with a positioning groove.

In one embodiment, the mounting ring and the flow inhibitor are both configured in a circular structure, the outer contour diameter of the mounting ring is greater than the outer contour diameter of the flow inhibitor, and the difference between the outer contour diameter of the mounting ring and the outer contour diameter of the flow inhibitor is less than or equal to 0.2mm.

An external rotor motor comprising the centrifugal fan of any one of the above.

The outer rotor motor adopts the centrifugal fan, and in the heat dissipation process, the fixing part rotates along with the starting of the motor body to drive the blades arranged circumferentially to rotate, so that heat in the motor body is driven to enter the air duct along with air flow, and the heat is discharged out of the centrifugal fan from the air duct, so that the heat dissipation of the motor body is realized. Because be provided with in the centrifugal fan and restrain the flow spare, and restrain the one end that the flow spare is located the blade subassembly and is kept away from the motor body, consequently, under the restraint of restraining the flow spare, the air current that restricts blade subassembly and is kept away from motor body one side flows in to the centrifugal fan, avoids the air current that flows back to the centrifugal fan to influence the total intake in the motor body. Through this centrifugal fan, so design, can effectively improve the air current flow direction, increase the total intake and the effective discharge of wind channel inside air current, improve air inlet efficiency to improve motor radiating efficiency.

An electric tool comprising the motor described above.

The electric tool adopts the centrifugal fan, and in the heat dissipation process, the fixed part rotates along with the starting of the motor body to drive the blades arranged circumferentially to rotate, so that heat in the motor body is driven to enter the air duct along with air flow, and the heat is discharged out of the centrifugal fan from the air duct, so that the heat dissipation of the motor body is realized. Because be provided with in the centrifugal fan and restrain the flow spare, and restrain the one end that the flow spare is located the blade subassembly and is kept away from the motor body, consequently, under the restraint of restraining the flow spare, the air current that restricts blade subassembly and is kept away from motor body one side flows in to the centrifugal fan, avoids the air current that flows back to the centrifugal fan to influence the total intake in the motor body. Through this centrifugal fan, so design, can effectively improve the air current flow direction, increase the total intake and the effective discharge of wind channel inside air current, improve air inlet efficiency to improve motor radiating efficiency.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application.

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a perspective view of a centrifugal fan structure according to some embodiments of the present application;

FIG. 2 is another perspective view of a centrifugal fan structure according to some embodiments of the present application;

FIG. 3 is a cross-sectional view of the centrifugal fan of FIG. 2 taken along the direction A-A;

FIG. 4 is a schematic view of a back side structure of a centrifugal fan according to some embodiments of the application;

FIG. 5 is a perspective view of a motor structure according to some embodiments of the present application;

FIG. 6 is another perspective view of a motor structure according to some embodiments of the present application;

FIG. 7 is a cross-sectional view of the motor of FIG. 6 taken along the direction B-B;

FIG. 8 is a diagram of airflow vectors for a centrifugal fan without a flow inhibitor in some embodiments of the application;

FIG. 9 is an airflow motion vector diagram of a centrifugal fan provided with a flow inhibitor in some embodiments of the application;

FIG. 10 is a schematic view of a centrifugal fan according to other embodiments of the present application;

FIG. 11 is a simulated schematic diagram of centrifugal fan noise distribution with and without steps in some embodiments of the application.

100. A centrifugal fan; 110. a fixing part; 120. a blade; 121. a body; 122. a mounting part; 123. a circular profile; 130. an air duct; 131. an air inlet end; 132. an axial opening; 133. a radial opening; 140. a flow inhibitor; 141. a flow guiding surface; 150. a mounting ring; 151. positioning the bulge; 160. a step; 200. a motor body; 210. an output shaft; 220. a stator; 230. a rotor; 231. and a positioning groove.

Detailed Description

In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the invention, whereby the invention is not limited to the specific embodiments disclosed below.

In some embodiments, please refer to fig. 1 and 5, a centrifugal fan 100 is used for dissipating heat of an external rotor motor, wherein the external rotor motor includes a motor body 200 and an output shaft 210. The output shaft 210 is driven by the motor body 200 and rotates about the axis of the output shaft 210. Centrifugal fan 100 includes a stationary portion 110 and a blade assembly. The fixed portion 110 is connected to the output shaft 210. The vane assembly includes a plurality of vanes 120, and the plurality of vanes 120 are disposed on the fixed portion 110 at intervals around the axis of the output shaft 210. An air duct 130 through which the air flow flows is formed between the adjacent two blades 120. The blade assembly also includes an air inlet end 131 that faces the motor body 200. Centrifugal fan 100 also includes a flow inhibitor 140. The flow suppressing member 140 is disposed on the fixing portion 110 and/or the blade 120, and is located at an end of the blade assembly facing away from the motor body 200, for suppressing the airflow on the side of the blade assembly facing away from the motor body 200 from flowing into the centrifugal fan 100.

In the above-mentioned motor, during the heat dissipation process, the fixing portion 110 rotates along with the start of the motor body 200 to drive the blades 120 disposed circumferentially to rotate, so as to drive the heat in the motor body 200 to enter the air duct 130 along with the air flow from one side of the motor body 200, and to be discharged from the air duct 130 to the outside of the centrifugal fan 100, so as to realize the heat dissipation of the motor body 200. Because the centrifugal fan 100 is provided with the flow inhibiting member 140, and the flow inhibiting member 140 is located at one end of the blade assembly, which is away from the motor body 200, under the inhibition of the flow inhibiting member 140, the air flow of the side, which is away from the motor body 200, of the blade assembly is limited to flow into the centrifugal fan 100, so that the air flow flowing back into the air duct is prevented from affecting the total air inlet quantity in the motor body 200. In addition, the flow inhibiting member 140 is disposed on the side of the blade assembly facing away from the motor body 200, so that the problem that the air flow is wandering in the air duct 130 and cannot be discharged due to backflow formed on the side of the blade assembly facing away from the motor body 200 can be avoided. Through this design, through this centrifugal fan 100, can effectively improve the air current flow direction, increase the total intake and the effective discharge of wind channel 130 inside air current, improve air inlet efficiency to improve motor radiating efficiency.

It should be noted that, when the flow inhibitor 140 is not provided, most of the airflow in the air duct 130 flows along the radial direction of the output shaft 210 under the centrifugal force, so as to be discharged out of the centrifugal fan 100; however, since the side of the blade assembly facing away from the motor body has an axial opening 132, the air flow from the side of the blade assembly facing away from the motor body will enter the air duct 130 through the opening. For the outer rotor motor, the gap width between the stator 220 and the rotor 230 for air intake is smaller, usually 0.5 mm-1 mm, which results in that the centrifugal fan 100 is sensitive to the backflow of the blade assembly back to the motor body, and the total air intake of the air duct air intake is greatly reduced, thereby greatly influencing the heat dissipation efficiency of the outer rotor motor.

Therefore, the present application sets the flow suppressing member 140 in the centrifugal fan 100, and covers the axial opening 132 of the centrifugal fan 100 facing away from the motor body 200 by using the flow suppressing member 140, so as to effectively suppress the air flow from the side of the centrifugal fan 100 facing away from the motor body 200 into the centrifugal fan 100, so as to increase the total air intake in the motor, and increase the effective air flow discharge amount in the air duct 130, thereby being beneficial to improving the heat dissipation efficiency of the outer rotor motor.

Since the air inlet end 131 of the air duct 130 and the motor body 200 are both positioned on the same side of the centrifugal fan 100, that is, the air inlet end 131 of the air duct 130 is arranged towards one side of the motor body 200; therefore, when the centrifugal fan 100 is started, air flows into the air duct 130 from one side of the motor body 200, so that heat in the motor body 200 is easily brought into the air duct 130, which is beneficial to improving the heat dissipation effect of the motor.

In addition, the implementation of the flow inhibitor 140 to inhibit airflow from the side of the blade assembly facing away from the motor body 200 into the centrifugal fan 100 may have a variety of designs, such as: the air outlet end of the air duct 130 in the axial direction of the fixed part 110 is covered or shielded by the flow inhibitor 140; or the flow inhibitor 140 is designed as a guiding structure such as a rotary impeller, so as to actively guide the airflow in the air duct 130 to flow along the radial direction of the output shaft 210, etc.

To facilitate understanding of the axial direction of the output shaft 210 and the radial direction of the output shaft 210, taking fig. 2 as an example, the axial direction of the output shaft 210 is the direction indicated by any arrow L1 in fig. 2; the radial direction of the output shaft 210 is indicated by any arrow L2 in fig. 2.

It should be noted that the number of the blades 120 is not particularly limited in the present embodiment, and may be determined according to the size of the motor or the operation power. Such as: for large-sized motors, the number of blades 120 may be designed to be large; for small-sized motors, the number of blades 120 is correspondingly smaller, such as: the number of blades 120 may be 12 to 33. Since the present fan is the centrifugal fan 100, the outer diameter of the centrifugal fan 100 should be greater than or equal to the diameter of the motor body 200. The diameter of the motor body 200 may be 28mm to 80mm.

Further, referring to fig. 1 to 3, the flow inhibitor 140 includes a flow guiding surface 141 disposed towards the motor body 200. The flow guiding surface 141 is disposed around the axial direction of the output shaft 210, and the flow guiding surface 141 at least partially covers or covers an end of the blade assembly facing away from the motor body 200, so that a part of the airflow enters the air duct 130 from the axial direction through the air inlet end 131, and then flows out of the air duct 130 from the radial direction along the flow guiding surface 141. It can be seen that during the heat dissipation process, the air flows from the axial direction of the centrifugal fan 100 into the air duct 130 from the air inlet end 131, and then flows out of the centrifugal fan 100 from the radial direction of the centrifugal fan 100. Because the axial opening 132 is covered by the flow inhibitor 140, the airflow entering the duct 130 is inhibited by the flow inhibitor 140 as it exits the axial opening 132 and exits radially along the flow inhibitor 140. Therefore, the flow guiding surface 141 of the flow restraining member 140 is used to restrain part of the airflow in the air duct 130 from flowing out of the axial opening 132, so as to reduce the air output of the centrifugal fan 100 on the side facing away from the motor body 200, and guide the airflow to flow out of the air duct 130 radially.

It should be noted that, the flow inhibitor 140 may directly cover the axial opening 132, or may form a shielding at the axial opening 132. Such as: the flow inhibitor 140 is directly sealed on the axial opening 132, so that part of the air flow cannot flow out of the axial opening 132; or the flow inhibitor 140 is arranged in the air duct 130 and forms a shield or the like at the axial opening 132. In this way, by using the shielding or covering manner of the flow inhibitor 140 to the axial opening 132, the airflow direction in the axial opening 132 is changed, so that the airflow on the side of the blade assembly, which is away from the motor body 200, is effectively inhibited from flowing into the centrifugal fan 100, and the total air intake of the centrifugal fan 100 is affected.

The end of the air duct 130 in the radial direction of the output shaft 210 and away from the fixed portion 110 may be defined as a radial opening 133. During the heat dissipation process, the air flow enters the air duct 130 from the air inlet end 131 by the axial direction of the centrifugal fan 100, and then flows out of the centrifugal fan 100 from the radial opening 133 by the radial direction of the centrifugal fan 100.

It should be noted that, the flow inhibitor 140 may have a complete circular structure or an annular structure. When the flow inhibitor 140 has a complete circular structure, it completely covers the fixing portion 110, and the peripheral edges (i.e., the peripheral edges) of the flow inhibitor 140 extend beyond the fixing portion 110 and cover or block at least a portion of each axial opening 132. When the flow inhibitor 140 is in an annular structure, the flow inhibitor 140 is disposed around the fixing portion 110 and connected to the blade assembly.

In addition, the flow inhibitor 140 may be concentrically disposed on the fixed portion 110; or may be arranged eccentrically. At the same time, the circumference of the flow inhibitor 140 may cover at least a portion of the axial opening 132, or may completely cover the axial opening 132.

Alternatively, the connection between the flow inhibitor 140 and the fixing portion 110 may be, but is not limited to, bolting, welding, bonding, pinning, riveting, integrally forming, etc. Wherein, the integral molding mode can be injection molding, die casting, extrusion and other modes.

Further, referring to fig. 1, the flow inhibitor 140 is disposed on the fixed portion 110, and a periphery of the flow inhibitor 140 extends out of the fixed portion 110 along a radial direction of the output shaft 210, and a portion of the flow inhibitor 140 extending out of the fixed portion 110 is connected to each of the blades 120. By the design, the integral structural strength of the centrifugal fan 100 is improved, the air tightness between the flow inhibiting piece 140 and the blades 120 is improved, and the air flow of the side, back to the motor body 200, of the blade assembly is prevented from flowing into the centrifugal fan 100 from a gap between the flow inhibiting piece 140 and the blades 120.

In some embodiments, referring to fig. 3, the flow inhibitor 140 is a plate-shaped member, and the thickness of the end of the plate-shaped member near the output shaft 210 is greater than the thickness of the end of the plate-shaped member far from the output shaft 210 in the radial direction of the output shaft 210. That is, the flow guiding surface 141 has a certain gradient from inside to outside in the radial direction of the output shaft 210, so that when the airflow on the flow guiding surface 141 is changed from axial flow to radial flow, the air outlet resistance of the airflow can be reduced, thereby being beneficial to improving the total air inlet volume in the motor (for example, the tested total air inlet volume is improved by 174%).

It should be noted that, the inclination angle of the flow guiding surface 141 may have various values, for example: the inclination angle α between the flow guide surface 141 and a plane perpendicular to the axis of the output shaft 210 may be 0 ° to 5 °.

Specifically, referring to fig. 1, in the radial direction of the output shaft 210, the thickness h of the flow inhibitor 140 gradually decreases from the middle of the flow inhibitor 140 to the periphery of the flow inhibitor 140, i.e., the flow inhibitor 140 gradually becomes thinner from inside to outside. Such as: the thickness h of the middle part of the flow inhibitor 140 is 2.9mm; the edge thickness h of the flow inhibitor 140 is 1.2mm.

In another embodiment, the thickness h of the flow inhibitor 140 in the radial direction of the output shaft 210 remains constant from the end near the output shaft 210 to the end far from the output shaft 210, i.e., the flow inhibitor 140 is of uniform thickness, such as: the thickness h of the flow inhibitor 140 is 1.2mm.

In some embodiments, referring to fig. 4, each of the blades 120 can define a circular profile 123 between the ends thereof remote from the fixed portion 110. The flow inhibitor 140 is configured as a circular structure, the center of the flow inhibitor 140 is concentrically arranged with the center of the circular contour 123, and the ratio of the diameter d1 of the outer contour of the flow inhibitor 140 to the diameter d2 of the circular contour 123 is 0.6-1. Thus, the diameter ratio between the blades 120 and the fixing portion 110 is reasonably controlled, so that the air output of the centrifugal fan 100 is more stable, and the heat dissipation efficiency of the motor is improved.

It should be noted that, the outer contour of the flow inhibitor 140 should be understood as: the contour formed by the perimeter of the flow inhibitor 140. In this embodiment, the flow inhibitor 140 may have a complete circular structure, and the outer diameter d1 is the diameter of the circular structure. Of course, the flow inhibitor 140 may also have an annular structure, and in this case, the outer contour diameter d1 is the outer diameter of the annular structure.

When the ratio between d1 and d2 is 0.6-1, the size ratio of the flow inhibitor 140 is properly increased, which is beneficial to further improving the air output of the centrifugal fan 100. Such as: the ratio between d1 and d2 may be, but is not limited to, 0.6, 0.7, 0.8, 0.9, 0.98, 1, etc. The larger the ratio between d1 and d2, the better the current suppressing effect, but the harder the process is to realize. Specifically, when the ratio between d1 and d2 is 0.9, the flow inhibition effect and the process realization difficulty can be simultaneously and effectively considered.

For convenience of explanation, the centrifugal fan 100 without the flow inhibitor 140 and the centrifugal fan 100 of the present embodiment are respectively subjected to airflow motion comparison analysis by computational fluid dynamics (Computational Fluid Dynamics, abbreviated CFD), and referring to fig. 8 and 9, for convenience of explanation, an air inlet area of the centrifugal fan 100 is indicated by a dashed box S1, an air outlet area of the centrifugal fan 100 is indicated by a dashed box S2, and a back side of the centrifugal fan 100 is indicated by a dashed box S3; and the return portion is indicated by a dashed box S4. Obviously, the air flow of the centrifugal fan 100 without the flow inhibitor 140 may form a backflow on the back side of the centrifugal fan 100, resulting in a reduction in the total air intake and air output of the centrifugal fan 100. After the flow inhibiting piece 140 is arranged, the airflow of the side, opposite to the motor body 200, of the blade assembly can be effectively inhibited from flowing into the centrifugal fan 100, and the air output and the total air input are effectively improved, so that the heat dissipation efficiency of the motor is improved.

In some embodiments, referring to fig. 10, the thickness of the blade 120 is denoted as D in the radial direction of the output shaft 210, and the thickness D tends to increase from the end of the blade 120 near the output shaft 210 to the end of the blade 120 far from the output shaft 210. Wherein, "in an increasing trend" means that the overall trend of the thickness D is increasing, i.e., the thickness of the blade 120 is thinner at one end near the output shaft 210; and thicker at the end remote from the output shaft 210, such as: firstly, gradually increasing; then, the constant or abrupt increase is reduced again; and then gradually increases. At one end near the output shaft 210, the thickness of the blades 120 is designed to be thinner, so as to increase the gap between two adjacent blades 120 and improve the air intake; at an end remote from the output shaft 210, the thickness of the blade 120 is designed to be thicker in order to enhance the structural strength of the blade 120. Of course, in other embodiments, the thickness of the blade 120 may also be uniform from the end of the blade 120 proximate the output shaft 210 to the end of the blade 120 distal from the output shaft 210.

As one example, the thickness of the blade 120 may be designed to vary uniformly. Specifically, in some embodiments, the thickness D increases gradually (or uniformly) from an end of the blade 120 proximate the output shaft 210 to an end of the blade 120 distal from the output shaft 210. Therefore, the air inlet efficiency is better by utilizing the uniform thickness change.

As yet another example, the thickness of the vane 120 may also be designed to vary non-uniformly, specifically, providing a step 160 structure or the like on the vane 120. In this example, the centrifugal fan with the step 160 structure on the air guiding side 124 and the centrifugal fan 100 with the uniformly variable thickness of the blades 120 are respectively assembled on the outer rotor motor to perform the air volume and noise test, and as a result, referring to table 1 and fig. 11, (a) in fig. 11 is a simulation diagram of the noise distribution of the centrifugal fan with the step 160; fig. 11 (b) is a schematic diagram showing a simulation of the noise distribution of a centrifugal fan without the step 160 (i.e., the centrifugal fan 100 in which the thickness of the blades 120 is uniformly varied); table 1 shows the total air volume of the centrifugal fan having steps and the centrifugal fan of the present application.

TABLE 1

As can be seen from Table 1, the total air volume of the centrifugal fan having the step 160 structure was 0.38L/S less than that of the centrifugal fan 100 having the uniform thickness variation of the blades 120, i.e., the total air volume of the centrifugal fan having the uniform thickness variation of the blades 120 was improved by 9.5%. Meanwhile, it should be explained that the internal air volume of the motor and the external air volume of the motor should be understood as: a larger gap is formed between the rotor 230 and the motor casing, and when the centrifugal fan 100 operates, a part of air flow dissipates heat to the stator 220 of the motor through the internal air passing through the rotor 230; the other part of the air flow passes through the outside of the rotor 230, and the heat dissipation effect of the part of the air flow on the stator 220 is not great, so that the part of the air flow should be restrained as much as possible during design.

As is clear from fig. 11 (a) and 11 (b), the maximum value of the noise generated by the centrifugal fan 100 in which the thickness of the blade 120 is uniformly changed is 2 db lower than the maximum value of the noise generated by the centrifugal fan having the step 160 structure.

In some embodiments, the blades 120 are also provided with a draft angle in the radial direction of the output shaft 210, such as: the demolding angle can be 0.5-1 degrees, so that the blade 120 can be molded integrally and demolded conveniently, and the molding rate of the product is improved.

In some embodiments, referring to fig. 1, each of the blades 120 includes a main body 121 and a mounting portion 122, one end of the main body 121 is connected to the fixing portion 110, and one end of the main body 121 remote from the fixing portion 110 extends along a side facing the motor body 200 to form the mounting portion 122. By such design, the air flow in the air duct 130 is smoother and the air output is larger by rotating the blades 120.

Centrifugal fan 100 also includes a mounting ring 150. The mounting ring 150 is connected to the mounting portion 122 of each blade 120, and the mounting ring 150 is coupled to the motor body 200 such that the motor body 200 drives the centrifugal fan 100 to rotate. In this way, the mounting ring 150 is coupled with the motor body 200, so that the centrifugal fan 100 is stably mounted on the motor body 200, and the centrifugal fan 100 is ensured to stably rotate.

Alternatively, the connection between the mounting ring 150 and the blade 120 may be, but is not limited to, bolting, welding, bonding, pinning, riveting, integrally forming, etc.

It should be noted that, the mounting ring 150 is coupled to the motor body 200, so that the motor body 200 drives the centrifugal fan 100 to rotate, for example: taking an external rotor motor as an example, the mounting ring 150 is directly coupled with the rotor 230 of the motor, and the rotation of the rotor 230 drives the mounting ring 150 to rotate, thereby realizing the rotation of the centrifugal fan 100. In addition, after the mounting ring 150 rotates, the mounting ring 150 may drive the output shaft 210 to rotate through the fixing portion 110 or the blade 120.

Further, referring to fig. 1 and 7, one of the mounting ring 150 and the motor body 200 is provided with a positioning protrusion 151, and the other is provided with a positioning slot 231. That is, the mounting ring 150 may be provided with a positioning protrusion 151, and the motor body 200 is provided with a positioning groove 231; alternatively, the mounting ring 150 may be provided with a positioning groove 231, and the motor body 200 is provided with a positioning protrusion 151. At the time of assembly, the positioning protrusions 151 are inserted into the positioning grooves 231, so that positioning and installation between the mounting ring 150 and the motor body 200 are realized. In particular, in some embodiments, in the motor body 200, the positioning protrusion 151 or the positioning groove 231 is provided on the rotor 230 of the motor body 200.

Specifically, referring to fig. 1, the positioning protrusion 151 is disposed on the mounting ring 150. Meanwhile, the plurality of positioning protrusions 151 are provided, and the plurality of positioning protrusions 151 are arranged at intervals around the circumference of the mounting ring 150. In addition, when the motor body 200 is an external rotor motor, the positioning groove 231 is a gap groove between the magnetic steels of the adjacent two rotors 230.

In some embodiments, referring to fig. 3 and 4, the mounting ring 150 and the flow inhibitor 140 are configured in a circular structure, the outer diameter d3 of the mounting ring 150 is larger than the outer diameter d1 of the flow inhibitor 140, and the difference between the outer diameter d3 of the mounting ring 150 and the outer diameter d1 of the flow inhibitor 140 is smaller than or equal to 0.2mm. With such design, the centrifugal fan 100 is convenient to be demolded, and the molding yield of the product is improved.

In some embodiments, an external rotor motor comprises the centrifugal fan 100 of any of the above.

The above outer rotor 230 motor adopts the above centrifugal fan 100, and in the heat dissipation process, the fixing portion 110 rotates along with the start of the motor body 200 to drive the circumferentially arranged blades 120 to rotate, so as to drive the heat in the motor body 200 to enter the air duct 130 along with the air flow, and to discharge the heat from the air duct 130 to the outside of the centrifugal fan 100, so as to realize heat dissipation of the motor body 200. Because the centrifugal fan 100 is provided with the flow inhibiting member 140, and the flow inhibiting member 140 is located at one end of the blade 120 component opposite to the motor body 200, under the inhibition of the flow inhibiting member 140, the air flow on one side of the blade 120 component opposite to the motor body 200 is limited to flow into the centrifugal fan 100, so that the air flow flowing back into the centrifugal fan 100 is prevented from affecting the total air inlet quantity in the motor body 200. Through this design, through this centrifugal fan 100, can effectively improve the air current flow direction, increase the total intake and the effective discharge of wind channel 130 inside air current, improve air inlet efficiency to improve motor radiating efficiency.

In some embodiments, referring to fig. 5, the motor body 200 further includes a stator 220 and a rotor 230, the stator 220 includes an iron yoke and a coil winding, and the rotor 230 includes a rotor frame and magnetic steel. An external rotor motor is a device in which a rotor 230 is sleeved outside a stator 220 so that the rotor 230 is externally rotated.

Referring to fig. 6 and 7, when the motor body 200 is an outer rotor 230 motor, the output shaft 210 is rotatably connected with the stator 220. The fixing portion 110 is rotatably sleeved on the output shaft 210. The rotor 230 is connected to the centrifugal fan 100 such that the centrifugal fan 100 rotates together with the rotor 230.

In some embodiments, a power tool includes the outer rotor motor of the above embodiments.

The above electric tool adopts the above external rotor motor, in the heat dissipation process, the fixing portion 110 rotates along with the start of the motor body 200, drives the circumferentially arranged blades 120 to rotate, drives the heat in the motor body 200 to enter the air duct 130 along with the air flow, and discharges the centrifugal fan 100 from the air duct 130, so as to realize heat dissipation of the motor body 200. Because the flow inhibiting member 140 is disposed in the centrifugal fan 100, a part of the airflow entering the air duct 130 is inhibited from flowing to the side of the centrifugal fan 100 opposite to the motor body 200 under the action of the flow inhibiting member 140, i.e. the air outlet on the back side of the centrifugal fan 100 is reduced, so that the problem that the airflow wanders in the air duct 130 and cannot be effectively discharged due to backflow formed on the back of the centrifugal fan 100 is avoided. Through this design, through this centrifugal fan 100, can effectively improve the air current flow direction, increase the effective discharge amount of wind channel 130 inside air current, improve motor radiating efficiency.

The electric tool may be, but not limited to, a screwdriver, a nailing gun, a blowing and sucking machine, etc.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.

Claims

1. A centrifugal fan for rotating under the drive of an outer rotor motor to radiate heat from the outer rotor motor, the centrifugal fan comprising:

The fixing part is connected with the output shaft of the outer rotor motor and is used for rotating around the axis of the output shaft under the drive of the output shaft so as to drive the centrifugal fan to rotate;

the blade assembly comprises a plurality of blades, the blades are arranged at intervals around the axis of the output shaft and driven by the fixing part to rotate around the axis of the output shaft, an air channel for air flow circulation is formed between two adjacent blades, and the blade assembly comprises an air inlet end facing the motor body of the outer rotor motor;

The centrifugal fan further comprises a flow inhibiting piece, wherein the flow inhibiting piece is arranged on the fixing part and/or the blades and is positioned at one end of the blade assembly, which is opposite to the motor body, and the flow inhibiting piece is used for inhibiting air flow on one side of the blade assembly, which is opposite to the motor body, from flowing into the centrifugal fan.

2. The centrifugal fan of claim 1, wherein the flow inhibitor includes a flow guiding surface disposed toward the motor body, the flow guiding surface being disposed about the axial direction of the output shaft, the flow guiding surface at least partially shielding or covering an end of the blade assembly facing away from the motor body for causing a portion of the airflow to flow radially out of the air duct along the flow guiding surface after entering the air duct from the air inlet end axially.

3. The centrifugal fan according to claim 2, wherein the flow suppressing member is provided on the fixed portion, and a peripheral edge of the flow suppressing member extends out of the fixed portion in a radial direction of the output shaft, and a portion of the flow suppressing member extending out of the fixed portion is connected to each of the blades.

4. A centrifugal fan according to claim 3, wherein the flow inhibitor is a plate-like member having a thickness, in a radial direction of the output shaft, at an end of the plate-like member near the output shaft that is greater than a thickness at an end of the plate-like member remote from the output shaft; or alternatively

The thickness of the plate-like member in the radial direction of the output shaft is kept constant from an end close to the output shaft to an end distant from the output shaft.

5. A centrifugal fan according to claim 3, wherein a circular contour is defined between the ends of the blades away from the fixing portion, the flow suppressing member is configured in a circular structure, the center of the flow suppressing member is arranged concentrically with the center of the circular contour, and the ratio of the diameter d1 of the outer contour of the flow suppressing member to the diameter d2 of the circular contour is in the range of 0.6-1.

6. The centrifugal fan according to claim 1, wherein the thickness of the blade increases in the radial direction of the output shaft from an end of the blade near the output shaft to an end of the blade away from the output shaft.

7. The centrifugal fan according to claim 6, wherein a thickness of the blade varies from 1mm to 3mm from an end of the blade near the fixing portion to an end of the blade remote from the fixing portion.

8. The centrifugal fan according to claim 1, wherein each of the blades includes a main body and a mounting portion, one end of the main body is connected to the fixing portion, and one end of the main body away from the fixing portion extends along a side toward the motor body to form the mounting portion;

The centrifugal fan further comprises a mounting ring, wherein the mounting ring is connected with the mounting part of each blade, and the mounting ring is used for being matched with the motor body so that the motor body drives the centrifugal fan to rotate.

9. The centrifugal fan according to claim 8, wherein one of the mounting ring and the motor body is provided with a positioning projection, and the other is provided with a positioning groove.

10. The centrifugal fan of claim 8, wherein the mounting ring and the flow inhibitor are each configured in a circular configuration, an outer profile diameter of the mounting ring is greater than an outer profile diameter of the flow inhibitor, and a difference between the outer profile diameter of the mounting ring and the outer profile diameter of the flow inhibitor is less than or equal to 0.2mm.

11. An external rotor motor comprising the centrifugal fan of any one of claims 1-10.

12. A power tool comprising the external rotor motor of claim 11.