Electric fan

Abstract

The invention discloses an electric fan which comprises a machine shell with a bearing chamber and a containing chamber, a stator and rotor assembly located in the containing chamber, a bearing located in the bearing chamber, a rotating shaft with one end penetrating through the bearing, a fan cover located on the front side of the machine shell, a first movable impeller located on the inner side of the fan cover and fixedly connected with the rotating shaft, and an exhaust port communicating with the outside. The engine is characterized in that a second impeller is further fixedly connected to one end of the rotating shaft, located between the bearing chamber and the first impeller and provided with an inlet end and an outlet end, the inlet end faces the bearing chamber, and the outlet end is in fluid communication with the exhaust port. When the second movable impeller is driven to rotate, a positive pressure area for preventing working air flowing out of the first movable impeller from flowing towards the bearing chamber can be generated near the outlet end; according to the scheme of the electric fan, working air carrying liquid can be effectively prevented from flowing towards the position where the bearing is located, and use is safer.

Description

Technical Field

[0001] The present application relates to the technical field of electric blowers, and in particular to a wet and dry dual-purpose electric blower for cleaning equipment. Background Art

[0002] When the wet and dry electric blower in the cleaning appliance industry is working, the working wind with water vapor or water droplets needs to be isolated from the inside of the motor body; this will lead to the waterproof problem of the wet and dry vacuum cleaner.

[0003] The rotating shaft in the rotor assembly usually appears in the working wind area and inside the motor body at the same time; the bearings installed on the rotating shaft are the weak link in the entire waterproof process; in tests and actual use of products, the most common damage to electric fans is bearing water damage, that is, working wind with water vapor or water droplets passes over the bearings and enters the inside of the motor body.

[0004] In the existing wet and dry dual-purpose electric fans, the waterproof treatment methods at the bearings are generally the following: the first is to set an oil seal at the front of the bearing, and use the interference fit between the rotating shaft and the oil seal hole to achieve a waterproof effect. However, since the rotating shaft is a rotating component and the oil seal is a stationary component, the relative movement speed between the two is high, and there is a pressure difference on both sides of the oil seal, it is difficult to meet the waterproof requirements of the electric fan throughout its life cycle; the second is to use a small gap fit between the rotating shaft and the bracket through hole and fill it with grease; the functions of the small gap fit and the filling with grease are: pressure reduction at the front end of the bearing and sealing lubrication; but under the condition of using a cleaning agent, the grease will gradually be washed away by the cleaning agent solution, and cannot meet the waterproof requirements of the electric fan throughout its life cycle; the third is labyrinth waterproofing; the bushing and the bracket are combined to set a labyrinth structure; the pressure difference between the front and rear of the bearing can be greatly reduced, but the labyrinth is essentially a connected structure, and water will still be "twisted" through the labyrinth in the form of a water film after long-term operation.

[0005] The commonly used waterproofing methods mentioned above can achieve waterproofing effects under certain time or working conditions. However, once water enters the front end of the bearing, the water will gather at the front end of the bearing due to the lack of outlet, eventually damaging the bearing. Once the water passes over the bearing, the life of the electric blower will end. Summary of the invention

[0006] In order to solve the problem in the prior art that the waterproofing at the bearing cannot achieve the expected effect, the purpose of the present application is to provide an electric fan with reliable waterproofing effect at the bearing.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical scheme: an electric blower, comprising a casing having a bearing chamber and a storage chamber, a stator-rotor assembly located in the storage chamber, a bearing located in the bearing chamber, a rotating shaft passing through the bearing at one end, a wind cover located on the front side of the casing, a first impeller located on the inner side of the wind cover and fixedly connected to the rotating shaft, and an exhaust port connected to the outside; a second impeller is also fixedly connected to one end of the rotating shaft, the second impeller is located between the bearing chamber and the first impeller, the second impeller has an inlet end and an outlet end, the inlet end faces the bearing chamber, the outlet end is fluidly connected to the exhaust port, and the second impeller is configured to generate a positive pressure zone near the outlet end when driven to rotate, which prevents the working wind flowing out of the first impeller from flowing toward the bearing chamber.

[0008] The present application scheme adds a second impeller between the bearing chamber of the electric blower and the first impeller. The second impeller generates a positive pressure zone near its outlet end through rotation and work to prevent the working wind from flowing toward the bearing chamber. This positive pressure zone can protect the bearing chamber, so that when the electric blower is working, humid working wind or aqueous solution will not enter the bearing through the positive pressure area; and even after the electric blower is stopped, in some extreme cases, if liquid enters the area, the second impeller can work to quickly remove the liquid when it is started next time, and the situation of more and more liquid will not occur.

[0009] In a specific embodiment, the first impeller is configured to generate a first positive pressure greater than the atmospheric pressure in a region near the second impeller when driven to rotate, the pressure in the positive pressure region is the second positive pressure, and the second positive pressure is at least 30 Pa greater than the first positive pressure. The difference between the first and second positive pressures provided in this embodiment ensures that the working wind will not pass over the second impeller and enter the region where the bearing chamber is located.

[0010] In a specific embodiment, the housing includes a front end wall and a rear end wall, the bearing chamber is located at the front end wall, a plurality of heat dissipation air inlets connected to the outside atmosphere are provided on the rear end wall, a plurality of heat dissipation air outlets connected to the storage chamber are provided at the front end wall, and the inlet end is close to the plurality of heat dissipation air outlets. The plurality of heat dissipation air outlets, the heat dissipation air outlets, and the position design scheme with respect to the inlet end provided in this embodiment enable the heat dissipation airflow flowing through the storage chamber to flow to the exhaust port via the outlet end under the action of the second impeller, so that the electric fan structure of this example can simultaneously meet the dual requirements of waterproofing and heat dissipation.

[0011] In a specific embodiment, the plurality of heat dissipation air outlets are located at the bearing chamber. The plurality of heat dissipation air outlet design solutions provided in this embodiment can be completed together with the step of processing the bearing chamber, and the manufacturing is simple.

[0012] In a specific embodiment, the electric blower further comprises a side channel, and the outlet end is in fluid communication with the exhaust port through the side channel. The side channel solution provided in this embodiment enables the airflow flowing out of the side channel to flow out of the exhaust port together with the working air.

[0013] In a specific embodiment, the electric blower further includes a diffuser, and the diffuser is located downstream of the first impeller; an exhaust channel is provided between the diffuser and the exhaust port, and the side channel intersects with the exhaust channel. The diffuser provided in this embodiment can simultaneously collect and guide the working wind flowing through the first impeller to the exhaust channel; the design of the side channel and the exhaust channel enables the electric blower to generate negative pressure in the side channel and the exhaust channel when working, thereby further helping the airflow flowing out of the outlet end of the second impeller to flow to the exhaust channel.

[0014] In a specific embodiment, a second diffuser blade is provided in the exhaust channel, and the intersection of the side channel and the exhaust channel is located upstream of the second diffuser blade. The second diffuser blade solution provided in this embodiment can collect and guide the working air flowing through the first impeller and the heat dissipation air flowing through the second impeller to the exhaust port at the same time.

[0015] In a specific embodiment, the casing includes a front bracket, the front bracket has an inner wall and an outer wall, the wind cover is connected to the front end of the outer wall, at least part of the storage chamber is located on the inner side of the inner wall, the diffuser and the exhaust port are both located on the inner side of the outer wall and the exhaust port is located on the rear side of the diffuser, and at least part of the side channel is defined by the diffuser and the inner wall.

[0016] In a specific embodiment, the first impeller includes a first end plate, a second end plate opposite to the first end plate, and a plurality of first impeller blades located between the first end plate and the second end plate; the second impeller includes a third end plate, a center column protruding backward from the center portion of the third end plate, an axial retaining ring extending toward the rear side from the outer edge of the third end plate, a plurality of second impeller blades located on the inner side of the axial retaining ring, and an opening opposite to the third end plate, and the center column is fixedly connected to the rotating shaft.

[0017] In a specific embodiment, the first impeller and the second impeller are an integrated component.

[0018] In a specific embodiment, the rotating shaft outputs a total shaft power when driven to rotate, and the shaft power consumed by the second impeller when driven to rotate does not exceed 10% of the total shaft power. In this embodiment, by limiting the shaft power of the second impeller, the influence of the addition of the second impeller on the work performance of the first impeller is reduced.

[0019] Other advantages of the present invention will be described in detail in the following specific embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A front view of an electric blower provided in an embodiment of the present application; Figure 2 for Figure 1 A front cross-sectional view of the electric fan in FIG. Figure 3 for Figure 1 An exploded view of the electric blower in FIG. 1 , wherein the front bracket is partially cut away; Figure 4 A three-dimensional image of a front bracket provided in an embodiment of the present application from a rear-to-front perspective; Figure 5 A three-dimensional image of a front bracket provided in an embodiment of the present application from a front to rear perspective; Figure 6 A front cross-sectional view of a front bracket provided in an embodiment of the present application; Figure 7 A three-dimensional diffuser provided in an embodiment of the present application Figure 1 ; Figure 8 A three-dimensional diffuser provided in an embodiment of the present application Figure 2 ; Fig. 9 A three-dimensional diagram of a second impeller provided in an embodiment of the present application; Fig.10 A three-dimensional diagram of a first impeller and a second impeller designed as one body provided in an embodiment of the present application; Fig.11 A main cross-sectional view of the structure after the first impeller, the second impeller, the diffuser and the front bracket are assembled according to an embodiment of the present application; Fig.12 for Fig.11 A magnified view at point A; Fig.13 A schematic diagram of the flow of working wind and heat dissipation airflow of an electric blower provided in an embodiment of the present application when in operation; Fig.14 for Fig.13 Enlarged view at B.

[0021] Among them: 100, electric fan; 10, housing; 11, storage chamber; 1, front bracket; 2, rear bracket; 3, rear end cover; 41, stator and rotor assembly; 42, control panel; 43, shaft; 44, bearing; 5, diffuser; 6, wind cover; 7, first impeller; 8, second impeller; 31, rear end wall; 32, cooling air inlet; 33, wiring hole; 61, working air intake; 71, first end plate; 72, second end plate; 73, first moving blade; 12, front end Wall; 13, inner wall; 14, outer wall; 15, second diffuser blade; 90, exhaust port; 91, exhaust channel; 16, bearing chamber; 161, heat dissipation air outlet; 162, through groove; 51, diffuser bracket; 52, first diffuser blade; 53, axial collar; 81, third end plate; 82, center column; 83, axial retaining ring; 84, second moving blade; 85, open mouth; 801, inlet end; 802, outlet end; 50, diffuser channel; 92, side channel. DETAILED DESCRIPTION

[0022] To describe the technical content, structural features, achieved purpose and effect of the application in detail, the technical solutions in the embodiments of the application will be described below in conjunction with the drawings in the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all of the embodiments. In the following description, for the purpose of explanation, many specific details are set forth to provide a detailed description of various exemplary embodiments or implementations of the invention. However, various exemplary embodiments may also be implemented without these specific details or in the case of one or more equivalent arrangements. In addition, various exemplary embodiments may be different, but not necessarily exclusive. For example, without departing from the inventive concept, the specific shape, structure and characteristics of the exemplary embodiment may be used or implemented in another exemplary embodiment.

[0023] In the following, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0024] The “front” and “back” mentioned in this application are as follows: Figure 1 Before and after shown.

[0025] In the present application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0026] The present application provides an electric blower, which can be assembled on a dry cleaning machine for use, and can also be assembled on a wet cleaning device that uses a cleaning fluid to clean a surface; and is particularly suitable for being assembled on a wet cleaning device for use.

[0027] refer to Figure 1-3 , which schematically shows an electric blower 100, which includes a casing 10 consisting of a front bracket 1, a rear bracket 2 and a rear end cover 3, a stator and rotor assembly 41, a control panel 42, a rotating shaft 43, a bearing 44, a diffuser 5, a wind cover 6, a first impeller 7 and a second impeller 8.

[0028] The housing 10 has a storage chamber 11, and the stator-rotor assembly 41, the control panel 42 and a part of the rotating shaft 43 are located in the storage chamber 11. The bearing 44, the first impeller 7 and the second impeller 8 are all connected to the front of the rotating shaft 43. The inner side of the wind cover 6 is located at the front side of the housing 10, the first impeller 7 is located at the inner side of the wind cover 6, and the second impeller 8 is located between the first impeller 7 and the bearing 44.

[0029] The rear end cover 3 includes a rear end wall 31, and a plurality of heat dissipation air inlets 32 connected to the outside atmosphere are provided on the rear end wall 31. The inside and outside of the storage chamber 11 can be connected through these heat dissipation air inlets 32. A wiring hole 33 for the power supply connection line to pass through is also provided in the middle of the rear end cover 3.

[0030] The wind cover 6 is an integrated housing structure, and a front end portion thereof is provided with a working air inlet 61 . When the first impeller 7 rotates, external working air flows into the first impeller 7 through the working air inlet 61 .

[0031] The first impeller 7 includes a first end plate 71 and a second end plate 72 arranged in a front-to-rear manner, and a plurality of first impeller blades 73 arranged in a circumferential direction and located between the first end plate 71 and the second end plate 72 .

[0032] refer to Figure 4 , 5and 6, which schematically illustrate the front bracket 1. The front bracket 1 is cylindrical and includes a front end wall 12, an inner wall 13, an outer wall 14 and a second diffuser blade 15. The second diffuser blade 15 is located between the inner wall 13 and the outer wall 14. The front bracket 1 has an exhaust port 90 connected to the outside atmosphere, and the exhaust port 90 is located at the rear end of the inner wall 13 and the outer wall 14. An exhaust passage 91 is formed between the inner wall 13 and the outer wall 14, extending from front to rear to the exhaust port 90 and passing through the second diffuser blade 15. A bearing chamber 16 is provided in the middle of the front end wall 12, and the bearing 44 is installed in the bearing chamber 16. A plurality of heat dissipation air outlets 161 arranged along the circumferential direction are provided on the inner wall of the bearing chamber 16, and the inside and outside of the storage chamber 11 can be connected through these heat dissipation air outlets 161. A plurality of through grooves 162 arranged along the circumferential direction are further provided on the front surface of the front end wall 12 and the outer surface of the inner side wall 13 , and these through grooves 162 connect the fluid to the exhaust passage 91 .

[0033] refer to Figure 7-8 , which schematically shows the diffuser 5 . The diffuser 5 is located downstream of the first impeller 7 and comprises an annular diffuser support 51 , first diffuser blades 52 located at the periphery of the diffuser support 51 , and an axial collar 53 integrally formed on the diffuser support 51 .

[0034] refer to Fig. 9 , which schematically shows the second impeller 8. The second impeller 8 includes a third end plate 81, a center column 82 protruding backward from the center of the third end plate 81, an axial retaining ring 83 extending from the outer edge of the third end plate 81 toward the rear side, a plurality of second impeller blades 84 located inside the axial retaining ring 83, and an opening 85 opposite to the third end plate 81. The center column 82 is fixedly connected to the front end of the rotating shaft 43. The second impeller 8 has an inlet end 801 and an outlet end 802 located inside and outside the second impeller blades 84. When the second impeller 8 rotates, a negative pressure area will be formed near the inlet end 801, and a positive pressure area will be formed near the outlet end 802, and the airflow can flow from the inlet end 801 to the outlet end 802.

[0035] The second impeller 8 used in this example is a semi-open centrifugal impeller; in fact, in other embodiments, the second impeller can also be a mixed flow impeller, and the impeller structure can also be closed or open. The second impeller can be independent or integrated with the first impeller.

[0036] refer to Fig.10 , which illustrates an example of an integrated design of the first impeller 7 and the second impeller 8. In this example, the first impeller 7 and the second impeller 8 are constructed as an integral component, and the second end plate 72 of the first impeller 7 is fixed to the third end plate 81 of the second impeller 8 as a whole.

[0037] Continue as Figure 2As shown, the front end of the air cover 6 abuts against the first end plate 71 of the first impeller 7 , and the rear end of the air cover 6 abuts against the front end of the outer side wall 14 .

[0038] The second impeller 8 is located at the front side of the front end wall 12 , with its inlet end 801 facing the bearing 44 , the bearing chamber 16 and the plurality of heat dissipation air outlets 161 , and its outlet end 802 docking with the through groove 162 .

[0039] A diffuser channel 50 is formed from front to back between the diffuser 5 and the outer side wall 14, and the diffuser channel 50 is located upstream of the exhaust channel 91. The working air flowing out of the first impeller 7 will be able to first enter the diffuser channel 50, and then flow to the exhaust channel 91. Due to the presence of the through groove 162, a side channel 92 will be formed between the diffuser bracket 51 and the front end wall 12 and the inner side wall 13. The side channel 92 will connect the outlet end 802 with the exhaust channel 91, that is, it can guide the airflow flowing out of the outlet end 802 to the exhaust channel 91. In this example, the intersection of the side channel 92 and the exhaust channel 91 is located upstream of the second diffuser blade 15, that is, the airflow flowing into the exhaust channel 91 from the side channel 92 merges with the working air flowing out of the diffuser channel 50, first passes through the second diffuser blade 15 for diffusion, and then is discharged from the exhaust port 90.

[0040] The front end of the rear bracket 2 is connected to the rear end of the inner wall 13 , and the rear end cover 3 covers the rear opening of the rear bracket 2 .

[0041] In other embodiments, the side channel may not directly intersect with the exhaust channel, but the end of the side channel may be directly upstream of the expansion channel, or even directly guided to the air outlet of the first impeller; the side channel for the heat dissipation airflow is guided to the intersection with the working air discharge path, which can generate negative pressure at the intersection of the side channel and the working air discharge path (such as the intersection of the side channel 92 and the exhaust channel 91) when the working air flows, thereby further helping the flow of the heat dissipation airflow. In other embodiments, a side channel or similar structure may not be provided, but the heat dissipation airflow flowing out of the outlet end of the second impeller is allowed to flow freely to the low-pressure area, that is, the heat dissipation airflow can be discharged from the exhaust port after merging with the working air, or it can be discharged outward alone.

[0042] In other embodiments, the heat dissipation air outlet may not be provided, but the inlet end of the second impeller is connected to the outside air through a separate channel fluid, and when the second impeller rotates, the outside air is continuously sucked into the inlet end; the solution of this embodiment is particularly suitable for situations where there is no need to use the heat dissipation airflow to dissipate the heat of the corresponding components inside the casing, such as when the electric fan is arranged with a high-efficiency heat dissipation casing.

[0043] like Figure 11-12As shown, it shows a structure in which the front bracket 1, the wind cover 6, the first impeller 7, the second impeller 8 and the diffuser 5 are assembled together.

[0044] The diffuser 5 is fixedly arranged on the inner side of the outer side wall 14 ; the axial collar 53 is located on the outer periphery of the axial retaining ring 83 . The outlet end 802 of the second impeller 8 faces the through groove 162 .

[0045] In order to reduce the interference of the axial collar 53 on the rotation of the second impeller 8 , the axial collar 53 and the axial retaining ring 83 are preferably clearance-fitted.

[0046] The axial collar 53 and axial retaining ring 83 used in this example are respectively located on the stationary diffuser 5 and the rotating second impeller 8, and the two cooperate with each other. In other embodiments, the functional components responsible for the axial collar and the axial retaining ring can also be arranged on the stationary components, such as becoming a part of the diffuser or the front bracket; or all arranged on the rotating components; in some embodiments of the electric fan, these functional components can also be omitted, and the pressure generated by the second impeller when doing work is required to be sufficient to balance the pressure generated by the first impeller of the electric fan near the second impeller; such as in the electric fan with radial air outlet.

[0047] In order to enable the first impeller 7 to maintain a certain vacuum suction capacity, assuming that the rotating shaft 43 is driven to rotate by the stator assembly in the stator-rotor assembly 41 and can output a total shaft power P to the outside, the shaft power P1 consumed when the second impeller 8 is driven to rotate is preferably not more than 10% of the total shaft power P, such as 8%, 5%, etc.

[0048] In addition, when the second impeller 8 is configured to be driven to rotate by the rotating shaft 43, the pressure of the positive pressure area formed near the outlet end 802 must be sufficient to prevent the working wind flowing out of the first impeller 7 from flowing toward the bearing chamber 16. Assuming that the first impeller 7 is configured to be driven to rotate, it can generate a first positive pressure P1 greater than the atmospheric pressure in the area close to the second impeller 8 (such as the area adjacent to or close to the outlet end 802), and the pressure of the positive pressure area formed near the outlet end 802 is the second positive pressure P2. The second positive pressure P2 is preferably at least 30Pa greater than the first positive pressure P1; such as 50Pa, 80Pa, or even 100Pa greater.

[0049] like Fig.13 , 14 As shown, it shows the flow of working wind and heat dissipation airflow in the electric fan 100 when the electric fan 100 is working; wherein the flow path of the working wind is the path shown by the hollow arrow; the flow path of the heat dissipation airflow is the path shown by the solid arrow; the details are as follows: When the rotating shaft 43 of the electric fan 100 rotates under the action of the stator-rotor assembly 41, it will drive the first impeller 7 and the second impeller 8 to rotate at the same time; wherein, the rotation of the first impeller 7 will cause the external working wind to enter the first impeller 7 through the working air intake port 61, and then flow through the first impeller 7 and enter the diffuser 5, and after being diffused in the diffusion channel 50 of the diffuser 5, continue to flow to the exhaust channel 91 on the rear side, and be discharged from the exhaust port 90 after secondary diffusion in the exhaust channel 91; at the same time, the rotation of the second impeller 8 will form a negative pressure area at the inlet end 801 facing the heat dissipation air outlet 161 and a positive pressure area at the docking through groove 162; in this case, the air in the storage chamber 11 will continuously flow from the heat dissipation air outlet 161 to the inlet end 801, and the external air The air will only enter the storage chamber 11 through the heat dissipation air inlet 32. After passing through the control panel 42 and the stator-rotor assembly 41, the air will further flow to the inlet end 801 through the heat dissipation air outlet 161, so that a flowing heat dissipation airflow is formed between the heat dissipation air inlet 32, the storage chamber 11 and the heat dissipation air outlet 161; the heat dissipation airflow entering the inlet end 801 will continuously flow toward the outlet end 802, and then flow into the side channel 92 through the through groove 162. Due to the pressure of the heat dissipation airflow, the heat dissipation airflow will further flow to the exhaust channel 91, thereby merging with the working air and flowing toward the exhaust port 90 together; in the process of the flow of the working air and the heat dissipation airflow, due to the existence of the positive pressure area near the outlet end 802 of the second impeller 8, the working air will not pass over the second impeller 8 and flow to the bearing 44.

[0050] The rotating second impeller 8 will form a "dynamic seal" effect on the front side of the bearing chamber 16, thereby effectively preventing the working wind from flowing near the bearing chamber 16, and the rotating second impeller 8 will also allow the heat dissipation airflow to continuously flow through the control board 42 and the stator-rotor assembly 41 and other components in the storage chamber 11, thereby achieving heat dissipation of the control board 42 and the stator-rotor assembly 41.

[0051] Therefore, in this case, by arranging the second impeller at the front end of the bearing of the electric blower, the second impeller will form a relatively independent working area on the front side of the bearing. This area will generate a positive pressure area and a negative pressure area. The pressure in the positive pressure area is greater than the pressure generated by the first impeller in the adjacent area. This setting will prevent the humid working wind or aqueous solution from entering the bearing through this relatively independent working area due to the existence of this pressure difference when the electric blower is working; even after the electric blower is shut down, in some extreme cases, if liquid enters this area, the second impeller can work to quickly discharge it into the exhaust channel through the side channel when it is turned on next time, so that the liquid will not accumulate more and more. Moreover, due to the existence of the negative pressure area, a flowing heat dissipation airflow will be formed between the heat dissipation air inlet, the storage chamber and the heat dissipation air outlet, so that the heat generated on the control panel and the stator and rotor assembly will be taken away immediately; therefore, the design of this case can meet the dual needs of waterproofing and heat dissipation at the same time.

[0052] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present application. Without departing from the spirit and scope of the present application, the present application may have various changes and improvements, and the scope of protection required by the present application is defined by the attached claims, description and their equivalents.

Claims

1. An electric fan, comprising a housing having a bearing chamber and a receiving chamber, a stator-rotor assembly located in the receiving chamber, a bearing located in the bearing chamber, a rotating shaft with one end passing through the bearing, a wind shield located at the front side of the housing, a first impeller located inside the wind shield and fixedly connected to the rotating shaft, and an exhaust port communicating with the outside; It is characterized in that A second impeller is also fixedly connected to one end of the rotating shaft, and the second impeller is located between the bearing chamber and the first impeller. The second impeller has an inlet end and an outlet end, the inlet end faces the bearing chamber, and the outlet end is fluidly connected to the exhaust port. The second impeller is configured to generate a positive pressure zone near the outlet end when driven to rotate, which prevents the working wind flowing out of the first impeller from flowing toward the bearing chamber.

2. The electric blower according to claim 1, It is characterized in that The first impeller is configured to generate a first positive pressure greater than atmospheric pressure in a region near the second impeller when driven to rotate, the pressure in the positive pressure region is a second positive pressure, and the second positive pressure is at least 30 Pa greater than the first positive pressure.

3. The electric blower according to claim 1, It is characterized in that The casing includes a front end wall and a rear end wall, the bearing chamber is located at the front end wall, a plurality of heat dissipation air inlets connected to the outside atmosphere are provided on the rear end wall, a plurality of heat dissipation air outlets connected to the storage chamber are provided on the front end wall, and the inlet end is close to the plurality of heat dissipation air outlets.

4. The electric blower according to claim 3, It is characterized in that The plurality of heat dissipation air outlets are located in the bearing chamber.

5. The electric blower according to claim 1, It is characterized in that The electric blower further comprises a side channel, and the outlet end is in fluid communication with the exhaust port through the side channel.

6. The electric blower according to claim 5, It is characterized in that The electric blower further comprises a diffuser, and the diffuser is located downstream of the first impeller; an exhaust passage is provided between the diffuser and the exhaust port, and the side passage intersects with the exhaust passage.

7. The electric blower according to claim 6, It is characterized in that A second diffuser blade is arranged in the exhaust passage, and the intersection of the side passage and the exhaust passage is located upstream of the second diffuser blade.

8. The electric blower according to claim 5, It is characterized in that The casing includes a front bracket, the front bracket has an inner wall and an outer wall, the wind cover is connected to the front end of the outer wall, at least part of the storage chamber is located on the inner side of the inner wall, the diffuser and the exhaust port are both located on the inner side of the outer wall and the exhaust port is located on the rear side of the diffuser, and at least part of the side channel is defined by the diffuser and the inner wall.

9. The electric blower according to claim 1, It is characterized in that The first impeller includes a first end plate, a second end plate opposite to the first end plate, and a plurality of first impeller blades located between the first end plate and the second end plate; the second impeller includes a third end plate, a center column protruding backward from the center portion of the third end plate, an axial retaining ring extending toward the rear side from the outer edge of the third end plate, a plurality of second impeller blades located inside the axial retaining ring, and an opening opposite to the third end plate, and the center column is fixedly connected to the rotating shaft.

10. The electric blower according to claim 1 or 9, It is characterized in that The first impeller and the second impeller are integrated components.

11. The electric blower according to claim 1, It is characterized in that The rotating shaft outputs a total shaft power when being driven to rotate, and the shaft power consumed by the second impeller when being driven to rotate does not exceed 10% of the total shaft power.

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