Motor impeller and axial flow fan

Abstract

The utility model relates to a motor movable impeller and an axial flow fan, the motor movable impeller is applied to the axial flow fan, and the axial flow fan comprises a static impeller, an air inlet cover and the motor movable impeller which are coaxially arranged; the motor movable impeller is arranged in the air inlet cover, the motor movable impeller is a centrifugal impeller, air enters the motor movable impeller in the axial direction and exits the motor movable impeller in the radial direction, the air inlet cover is used for guiding radial airflow of the motor movable impeller to turn into axial airflow, and the static impeller is an axial impeller; the air inlet cover comprises an inner bent wall face, the motor movable impeller comprises a front disc, a rear disc and blades arranged between the front disc and the rear disc, the front disc is close to the inner bent wall face, the rear disc is close to a hub of the static impeller, and a flow channel of the motor movable impeller is communicated with the bent flow channel. The front disc comprises a circular ring part and a first expansion part which are integrally formed, and the first expansion part is arranged on the outer edge of the front disc and expands in the direction away from the rear disc. The flow separation in the flow channel can be improved when the movable impeller has axial installation deviation, and the flow loss is reduced.

Description

Technical Field

[0001] The present disclosure relates to the technical field of axial flow fans, and in particular to a motor impeller and an axial flow fan. Background Art

[0002] High-speed small motors are axial flow fans used in small household appliances. They are generally composed of a moving impeller and one or more stationary impellers, with the moving impeller located upstream of the stationary impeller group. At present, in the actual assembly process of axial flow fans, the installation of the moving impeller is prone to axial position deviation, resulting in the impeller's flow channel outlet and the subsequent flow channel inlet not being aligned, thereby generating a recirculation zone in the flow channel, affecting the aerodynamic performance of the axial flow fan. Summary of the invention

[0003] In order to solve at least one of the above-mentioned technical problems, the present disclosure proposes a motor impeller and an axial flow fan.

[0004] According to some embodiments of the present disclosure, a motor impeller is provided, which is applied to an axial flow fan, wherein the axial flow fan comprises a coaxially arranged stationary impeller, an air intake hood and the motor impeller; the motor impeller is arranged in the air intake hood, the motor impeller is a centrifugal impeller, the motor impeller takes in air axially and discharges air radially, the air intake hood is used to guide the radial airflow of the motor impeller to turn it into an axial airflow, the stationary impeller is installed downstream of the motor impeller in the wind direction, and the stationary impeller is an axial impeller; The air intake hood includes an inner curved wall surface, and a curved flow channel is formed between the inner curved wall surface and the side wall of the hub of the stationary impeller. The motor impeller includes a front disk, a rear disk and blades arranged between the front disk and the rear disk. The front disk is close to the inner curved wall surface, and the rear disk is close to the hub of the stationary impeller. The flow channel of the motor impeller is connected to the curved flow channel. The front disk includes an integrally formed annular portion and a first expansion portion, and the first expansion portion is arranged at the outer edge of the front disk, and the first expansion portion expands in a direction away from the rear disk.

[0005] Based on the above scheme, the air inlet hood is provided with an inner curved wall surface, and the edge of the front disk of the impeller is expanded outward. When there is an axial installation deviation of the impeller, the airflow flows out along the first expansion part of the front disk, and then impacts and adheres to the inner curved wall surface, and completes the turn along the inner curved wall surface, thereby improving the airflow separation, reducing the flow loss, and thus enhancing the aerodynamic performance of the axial flow fan.

[0006] In some possible embodiments, the profile projection of the inner curved wall surface on the radial section is a spline curve, and the spline curve includes two smoothly connected arc segments, the center of the arc segment close to the rear disc is located inside the air intake hood, and the center of the arc segment close to the front disc is located outside the air intake hood.

[0007] Based on the above scheme, the front end edge of the air inlet hood is expanded outward, and the first expanded portion of the front disc can be aligned with the front end edge of the air inlet hood within a certain axial distance range of the impeller, further reducing the influence of the axial installation deviation of the impeller on the aerodynamic performance of the axial flow fan.

[0008] In some possible implementations, the termination point of the inner wall of the annular portion points to the inner curved wall surface, and the inner wall extension surface of the annular portion transitions tangentially to the inner curved wall surface.

[0009] Based on the above scheme, by limiting the inner wall guidance of the annular portion, the flow direction of the airflow when it flows out of the impeller through the front disk is consistent with the inlet direction of the curved flow channel, so that the airflow has a certain axial speed, thereby improving the flow separation caused by the turning speed loss of the airflow in the curved flow channel.

[0010] In some possible implementations, the end point of the inner wall of the first expansion portion points to the inner curved wall surface, and the intersection line between the inner wall extension surface of the first expansion portion and the inner curved wall surface is close to the starting point of the inner curved wall surface.

[0011] Based on the above scheme, the direction of the first expansion portion is limited, the airflow out of the front disk can be aligned with the inner curved wall of the air intake cover, and the impeller has a certain axial installation range, which can reduce the impact of axial installation deviation.

[0012] In some possible embodiments, a round chamfer is provided on a side of the hub of the stationary impeller close to the motor impeller, and the rear disc includes an integrally formed disc portion and a second expansion portion, the second expansion portion is provided at the outer edge of the rear disc, the second expansion portion expands in a direction away from the front disc, and the end point of the second expansion portion points to the round chamfer.

[0013] Based on the above scheme, the rear disc is designed to be outward-expanded, and the airflow flowing out along the rear disc of the moving impeller has a certain axial velocity component. When it flows to the circular chamfer of the stationary impeller hub, the angle between the airflow velocity direction and the hub wall is small, and the airflow has a strong ability to adhere to the wall, thereby suppressing the flow separation of the airflow and reducing the flow loss of the airflow.

[0014] In some possible implementations, the projection of the profile of the inner wall of the first expansion portion on the radial section is a straight line or a smooth curve, and the projection of the profile of the inner wall of the second expansion portion on the radial section is a straight line or a smooth curve.

[0015] Based on the above solution, the structural features of the first expansion portion and the second expansion portion are defined, and the smoothness of the airflow is ensured through the profile design.

[0016] In some possible implementations, the profile projection of the inner wall of the first expansion portion on the radial section is an arc, and the extended surface of the inner wall of the first expansion portion forms an obtuse angle with the inner curved wall surface.

[0017] Based on the above solution, the airflow flowing out along the first expansion portion has both a wall-pressing velocity and a wall-adjacent velocity when impacting the inner curved wall surface, which can enhance the wall attachment ability of the airflow and improve the flow separation phenomenon of the airflow.

[0018] In some possible implementations, a profile projection of the inner wall of the second expansion portion on a radial section is an arc, and an extended surface of the inner wall of the second expansion portion points to a starting point of the fillet.

[0019] Based on the above solution, the airflow flowing out along the second expansion portion can smoothly transition to the side wall of the stationary impeller, thereby maintaining the stability of the airflow and reducing the possibility of flow separation.

[0020] In some possible implementations, an axial distance between a starting point of the inner curved wall surface and a starting point of a hub of the stationary impeller is greater than an axial distance between a termination point of the first expansion portion and a termination point of the second expansion portion.

[0021] Based on the above scheme, the flow channel outlet of the impeller is smaller than the inlet of the curved flow channel, and the impeller has a certain degree of freedom of axial movement. When the impeller has an axial installation deviation, the flow channel of the impeller can still be aligned with the curved flow channel, thereby reducing the impact of the axial installation deviation.

[0022] According to some other embodiments of the present disclosure, an axial flow fan is provided, comprising a motor impeller according to any one of the above embodiments.

[0023] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

[0024] Further features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions and advantages in the embodiments of this specification or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 A schematic diagram showing the axial installation deviation of the impeller of an axial flow fan;

[0027] Figure 2 A radial cross-sectional view of a motor impeller according to an embodiment of the present disclosure is shown;

[0028] Figure 3 A partially enlarged view showing a radial section of a motor impeller according to an embodiment of the present disclosure;

[0029] Figure 4 The figure shows the airflow effect diagram of the front disc of the impeller in the related art;

[0030] Figure 5 A diagram showing the airflow effect of a front disk of a motor impeller according to an embodiment of the present disclosure;

[0031] Figure 6 The following is a diagram showing the effect of airflow on the rear disc of the impeller in the related art;

[0032] Figure 7 A diagram showing the airflow effect of a rear disc of a motor impeller according to an embodiment of the present disclosure is shown;

[0033] Figure 8 The figure shows the distribution diagram of the moving impeller and the stationary impeller of the axial flow fan in the related art.

[0034] In the figure:

[0035] 1. Inwardly curved wall; 2. Front disc; 21. Annular portion; 22. First expansion portion; 3. Rear disc; 31. Disc portion; 32. Second expansion portion; 4. Hub; 41. Round chamfer. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or server that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or devices.

[0038] Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0039] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0040] The term "and / or" herein is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set consisting of A, B, and C.

[0041] In addition, in order to better illustrate the present disclosure, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present disclosure can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present disclosure.

[0042] It is worth noting that, unless otherwise specified, the directions in the embodiments of the present disclosure are defined according to the direction of the airflow. For example, according to the direction of the airflow, the upstream is the front and the downstream is the back; or, the upstream is the starting point and the downstream is the end point, etc.

[0043] A high-speed small motor is an axial flow fan used in small household appliances (such as vacuum cleaners, floor scrubbers, sweeping robots, etc.). It is generally composed of a moving impeller and one or more stationary impellers. The moving impeller is located upstream of the stationary impeller group. The moving impeller adopts a backward centrifugal form, and the stationary impeller adopts an axial form. The airflow enters the moving impeller axially and flows out radially. The airflow flowing out of the moving impeller enters the stationary impeller again. There is a transition section flow channel between the moving impeller and the stationary impeller, which converts the radial component of the air velocity at the moving impeller outlet into the axial direction. The flow loss of the airflow increases when turning, which reduces the overall aerodynamic performance of the fan. Figure 8 The distribution diagram of the moving impeller and the stationary impeller of the axial flow fan is shown.

[0044] At present, during the production and assembly process of axial flow fans, the installation of the impeller is prone to axial position deviation, which makes it impossible for the impeller flow channel outlet to align with the transition section flow channel inlet. Figure 1As shown in the figure, when the volume of the axial flow fan is small, even a small axial installation deviation can have a great impact on the aerodynamic performance of the axial flow fan. For example, if the outlet width of the impeller flow channel is 5mm and the axial installation deviation of the impeller is 0.5mm, the width of the impeller flow channel is occupied by 10%. Due to the axial installation deviation of the impeller, part of the airflow is blocked and cannot flow into the transition section flow channel at the first time. The airflow is separated due to the uneven flow velocity, and a recirculation zone is generated near the side wall of the transition section flow channel, which in turn causes the airflow velocity distribution at the inlet of the stator wheel to change, and a recirculation zone is generated on the side wall of the hub of the first-stage stator wheel, and the recirculation zone on the side wall of the hub of the second-stage stator wheel is expanded, which ultimately leads to a decrease in the aerodynamic performance of the axial flow fan.

[0045] In order to solve the above-mentioned technical problems, an embodiment of the present disclosure provides a motor impeller, which is applied to an axial flow fan. The embodiment of the present disclosure adjusts the structure of the motor impeller so that the flow channel outlet of the motor impeller expands outward, and the airflow flowing out of the motor impeller has a stronger wall adhesion force in the transition section flow channel, thereby improving the airflow backflow in the transition section flow channel and the stationary impeller hub position.

[0046] Figure 2 An axial cross-section view of an axial flow fan is shown. The axial flow fan includes a coaxially arranged stationary impeller, an air inlet hood and a motor impeller. The motor impeller is arranged in the air inlet hood. The motor impeller is a centrifugal impeller. The motor impeller takes in air axially and discharges air radially. The stationary impeller is installed downstream of the motor impeller in the wind direction. The stationary impeller is an axial impeller.

[0047] The air intake hood is used to guide the radial airflow of the motor impeller to turn it into an axial airflow. The flow channel formed between the air intake hood and the side wall of the hub 4 of the stationary impeller is the above-mentioned transition section flow channel. The air intake hood includes an inner curved wall surface 1. A curved flow channel is formed between the inner curved wall surface 1 and the side wall of the hub 4 of the stationary impeller. The radial airflow flowing out of the motor impeller is changed into an axial airflow along the curved flow channel and flows into the stationary impeller. The air intake hood also includes a front section, which is used for air intake. In the axial section view, the profile of the front section close to the inner curved wall surface 1 is a straight line, and the profile of the inner curved wall surface 1 is a smooth curve that is curved inward as a whole.

[0048] The impeller of the motor includes a front disc 2, a rear disc 3 and blades arranged between the front disc 2 and the rear disc 3. The front disc 2 is close to the inner curved wall surface 1, and the rear disc 3 is close to the hub 4 of the stationary impeller. The blades are evenly distributed along the circumference, and the flow channel of the impeller of the motor is connected to the curved flow channel. Figure 2As shown, the front disc 2 includes an integrally formed annular portion 21 and a first expansion portion 22, the first expansion portion 22 being arranged at the outer edge of the front disc 2, and the first expansion portion 22 expanding in a direction away from the rear disc 3. Based on the above structure, in the radial air outlet of the motor impeller, part of the airflow adheres to the inner wall of the front disc 2 and flows out, then hits the inner curved wall surface 1 of the air intake cover, and continues to flow along the inner curved wall surface 1 until the airflow direction turns axial. It should be understood that the inner wall of the first expansion portion 22 should be smooth and continuous, and the airflow has a low speed loss when flowing along the first expansion portion 22. Therefore, the line projection of the inner wall of the first expansion portion 22 on the radial section is a straight line or a smooth curve, that is, the line projection of the inner wall of the first expansion portion 22 on the radial section can be a straight line segment, a single arc or a spline curve.

[0049] In the disclosed embodiment, please refer to Figure 4 and Figure 5 The purpose of the outward expansion design of the front disc 2 of the motor impeller is that the airflow that flows out from the inner wall of the front disc 2 can have both the wall pressure velocity and the wall speed when impacting the inner curved wall surface 1, the airflow has a strong wall attachment ability and a small degree of velocity loss, thereby suppressing the flow separation of the airflow. Since the air intake cover is provided with the inner curved wall surface 1, when there is a certain axial installation deviation of the motor impeller, the first outward expansion part of the front disc 2 sends the airflow to the inner curved wall surface 1 of the air intake cover, and the airflow climbs along the inner curved wall surface 1, which can improve the degree of airflow accumulation, thereby reducing and eliminating the reflow area near the side wall surface of the transition section flow channel.

[0050] In the disclosed embodiment, the connection between the front section of the air intake hood and the inner curved wall surface 1 should be relatively gentle, otherwise the inner curved wall surface 1 is relatively steep as a whole, making it difficult for the airflow to climb along the wall, and the airflow velocity loss is large, which can easily lead to flow separation. Figure 2 and Figure 3 The projection of the inner curved wall surface 1 on the radial section is a spline curve, which includes two smoothly connected arc segments. The arc segment close to the rear disc 3 is an inner curved arc, whose center is located inside the air intake hood, and the arc segment close to the front disc 2 is an outer curved arc, whose center is located outside the air intake hood. The two ends of the outer curved arc are respectively connected to the inner curved arc and a straight line.

[0051] Based on the structure of the inner curved wall surface 1, the structure of the first expansion portion 22 of the front plate 2 needs to be adjusted accordingly. Specifically, the end of the inner wall of the first expansion portion 22 points to the inner curved wall surface 1, and the intersection line between the inner wall extension surface of the first expansion portion 22 and the inner curved wall surface 1 is close to the starting point of the inner curved wall surface 1. Figure 3 In the radial section view, the above structure can be expressed as follows: the inner wall extension line of the first expansion portion 22 intersects with the profile line of the inner curved wall surface 1, and the intersection point is located after the starting point of the profile line of the inner curved wall surface 1. The inner wall extension line of the first expansion portion 22 and the profile line of the inner curved wall surface 1 intersect at the intersection point. Figure 3The midpoint T is the starting point of the profile of the inner curved wall 1. Figure 3 Midpoint L. It should be understood that point T moves according to the actual installation position of the motor impeller, and the movement range of point T is after point L. When point T and point L just coincide, the airflow that fits the inner wall of the first expansion portion 22 can just rush to the starting point of the inner curved wall surface 1. When the motor impeller is in the ideal installation position, there is a certain axial distance between point T and point L. This axial distance is the preset installation error range of the motor impeller. When the axial installation deviation of the motor impeller is less than or equal to the axial distance, the axial installation deviation of the motor impeller will not affect the aerodynamic performance of the axial flow fan.

[0052] According to the above-mentioned embodiments, one of the reasons that affects the aerodynamic performance of the axial flow fan is that the radial air outlet of the motor impeller loses too much velocity in the process of converting to axial air outlet, resulting in flow separation and the generation of a vortex recirculation zone. In order to reduce the velocity loss of the airflow, the structure of the front disk 2 is adjusted in the embodiment of the present disclosure so that the airflow outlet of the motor impeller has an axial velocity component. Specifically, the end of the inner wall of the annular portion 21 points to the inner curved wall surface 1, and the inner wall extension surface of the annular portion 21 transitions tangently to the inner curved wall surface 1. In the radial section view, the extension line of the contour line of the annular portion 21 is tangent to the contour line of the inner curved wall surface 1. Based on the above structure, the airflow flowing out of the motor impeller flow channel can flow smoothly into the curved flow channel, and the friction energy consumption of the airflow is reduced, thereby reducing the velocity loss and improving the aerodynamic performance of the fan.

[0053] In an axial flow fan, since the motor impeller is a centrifugal impeller, affected by the inertia of the axial velocity of the inlet airflow of the centrifugal impeller, the airflow velocity on the outlet rear disc 3 side of the motor impeller is relatively large, and the airflow wall adhesion ability is relatively weak. Please refer to Figure 6 When the airflow flows out along the inner wall of the rear disc 3, it first continues to flow radially, and then slowly turns to the axial direction, resulting in a low airflow velocity at the side wall of the stator impeller hub 4, an uneven distribution of the overall airflow velocity, and a low-speed vortex, i.e., a recirculation zone, gradually forming at the side wall of the stator impeller hub 4. When there is an axial installation deviation of the motor impeller, the rear disc 3 is far away from the stator impeller hub 4, which will cause the above-mentioned recirculation zone to expand further, and the aerodynamic performance of the axial flow fan will be reduced.

[0054] To solve the above problems, please refer to Figure 2 , Figure 3 and Figure 7, the hub 4 of the stationary impeller is provided with a round chamfer 41 on one side close to the motor impeller, the rear disc 3 includes an integrally formed disc portion 31 and a second expansion portion 32, the second expansion portion 32 is provided at the outer edge of the rear disc 3, the second expansion portion 32 expands in a direction away from the front disc 2, and the end of the second expansion portion 32 points to the round chamfer 41. Based on the above structure, the airflow flowing out along the inner wall of the rear disc 3 has a certain axial velocity component, and the velocity loss is small during the process of the airflow turning into the axial direction, which reduces the probability of airflow flow separation, thereby improving the aerodynamic performance of the axial flow fan. It should be understood that the inner wall of the second expansion portion 32 should be smooth and continuous, and the velocity loss is low when the airflow flows along the second expansion portion 32. Therefore, the line projection of the inner wall of the second expansion portion 32 on the radial section is a straight line or a smooth curve, that is, the line projection of the inner wall of the second expansion portion 32 on the radial section can be a straight line segment, a single arc or a spline curve.

[0055] The above-mentioned multiple embodiments have clearly introduced how to adjust the structure of each component of the motor impeller to improve the aerodynamic performance of the axial flow fan. In the absence of conflict, the features of the above-mentioned multiple embodiments can be freely combined to form a new solution.

[0056] In a specific embodiment, please refer to Figure 2 and Figure 3 The front disk 2 and the rear disk 3 of the motor impeller are simultaneously designed to be expanded outward, and the line projection of the inner curved wall surface 1 on the radial section is a spline curve, and the spline curve includes two smoothly connected arc segments.

[0057] like Figure 3As shown, the line projection of the inner wall of the first expansion portion 22 on the radial section is an arc, the extended surface of the inner wall of the first expansion portion 22 forms an obtuse angle with the inner curved wall surface 1, the distance from the starting point of the first expansion portion 22 (point S in the figure) along the inner wall line direction of the annular portion 21 to the outlet of the motor impeller is c1, and the axial distance between the starting point of the first expansion portion 22 and the starting point of the second expansion portion 32 is b1, b1 is the minimum axial distance between the front disk 2 and the rear disk 3, 0.2*b1 ≤c1≤0.45*b1, in some preferred embodiments, 0.25*b1≤c1≤0.3*b1; and the arc radius of the first expansion portion 22 is r1, 1.3*c1≤r1≤1.8*c1, in some preferred embodiments, 0.25*b1≤c1≤0.3*b1; the expansion angle kf of the first expansion portion 22 satisfies: 25°≤kf≤58°, in some preferred embodiments, 35°≤kf≤45°. Based on the above parameter control, when the axial relative position of the motor impeller changes within a certain range, the airflow flowing from the outlet of the front disk 2 to the inlet of the curved flow channel, due to the outward expansion of the flow channel, the airflow can have a velocity component that rushes to the outer arc side wall of the transition section flow channel, that is, the wall pressure velocity component. This part of the gas kinetic energy can make the airflow have a stronger tendency to flow against the wall, inhibit the flow separation of the curved flow channel, and reduce the flow loss.

[0058] like Figure 3 As shown, the projection of the inner wall of the second expansion portion 32 on the radial section is an arc, and the extended surface of the inner wall of the second expansion portion 32 points to the starting point of the fillet 41, and the distance c2 from the starting point of the second expansion portion 32 along the inner wall profile direction of the disc portion 31 to the outlet of the motor impeller satisfies: 0.2*b1≤c2≤0.4*b1, in some preferred embodiments, c2=0.25*b1; and the arc radius of the second expansion portion 32 is r2, 1.8*c2≤r2≤3*c2, in some preferred embodiments, 2*c2≤r2≤2.5*c2. Based on the above parameter control, the airflow at the outlet of the rear disc 3 will have a certain axial velocity component due to the outward expansion structure, rather than purely radially flowing out of the motor impeller. Therefore, when the airflow flows to the side wall of the curved channel hub 4, the angle between the airflow velocity direction and the horizontal wall of the hub 4 is smaller, and the airflow has a stronger ability to adhere to the wall, which suppresses the flow separation of the airflow on the side wall of the curved channel hub 4 and the side wall of the hub 4 behind it, and also reduces the flow loss.

[0059] like Figure 3 As shown, in this embodiment, the axial distance between the starting point of the inner curved wall surface 1 and the starting point of the hub 4 of the stationary impeller is ( Figure 3 b) is greater than the axial distance between the end point of the first expansion portion 22 and the end point of the second expansion portion 32 ( Figure 3b2), in a further embodiment, 1.05*b2≤b≤1.3*b2, in some preferred embodiments, 1.12*b2≤b≤1.17*b2; the axial distance b1 between the starting point of the first expansion portion 22 and the starting point of the second expansion portion 32 satisfies: 0.8*b2≤b1≤0.96*b2, in some preferred embodiments, 0.86*b2≤b1≤0.92*b2.

[0060] This embodiment can greatly reduce the technical problem of axial fan performance degradation caused by axial installation deviation by respectively expanding the front disk 2 and the rear disk 3 of the motor impeller and matching the size parameters, thereby reducing the sensitivity of the fan assembly process to performance.

[0061] The disclosed embodiments further provide an axial flow fan, comprising a motor impeller according to any one of the above embodiments.

[0062] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A motor impeller, used in an axial flow fan, characterized in that: The axial flow fan comprises a coaxially arranged stationary impeller, an air intake cover and a motor impeller; The motor impeller is arranged in the air intake cover, the motor impeller is a centrifugal impeller, the motor impeller takes in air axially and discharges air radially, the stationary impeller is installed downstream of the motor impeller in the wind direction, the air intake cover is used to guide the radial airflow of the motor impeller to turn it into an axial airflow, and the stationary impeller is an axial impeller; The air inlet hood comprises an inner curved wall surface (1), a curved flow channel is formed between the inner curved wall surface (1) and the side wall of the hub (4) of the stationary impeller, the motor impeller comprises a front disc (2), a rear disc (3) and blades arranged between the front disc (2) and the rear disc (3), the front disc (2) is close to the inner curved wall surface (1), the rear disc (3) is close to the hub (4) of the stationary impeller, and the flow channel of the motor impeller is connected to the curved flow channel; The front disc (2) comprises an integrally formed annular portion (21) and a first expansion portion (22), wherein the first expansion portion (22) is arranged at an outer edge of the front disc (2), and the first expansion portion (22) expands in a direction away from the rear disc (3).

2. The impeller of the motor according to claim 1, characterized in that: The projection of the profile of the inner curved wall surface (1) on the radial section is a spline curve, and the spline curve includes two smoothly connected arc segments, the center of the arc segment close to the rear disc (3) is located inside the air intake hood, and the center of the arc segment close to the front disc (2) is located outside the air intake hood.

3. The impeller of the motor according to claim 2, characterized in that: The end point of the inner wall of the annular portion (21) points to the inner curved wall surface (1), and the inner wall extension surface of the annular portion (21) transitions tangentially to the inner curved wall surface (1).

4. The impeller of the motor according to claim 2, characterized in that: The end point of the inner wall of the first expansion portion (22) points to the inner curved wall surface (1), and the intersection line between the inner wall extension surface of the first expansion portion (22) and the inner curved wall surface (1) is close to the starting point of the inner curved wall surface (1).

5. The impeller of the motor according to any one of claims 1 to 4, characterized in that: A round chamfer (41) is provided on the side of the hub (4) of the stationary impeller close to the impeller of the motor, and the rear disc (3) includes an integrally formed disc portion (31) and a second expansion portion (32), wherein the second expansion portion (32) is provided at the outer edge of the rear disc (3), and the second expansion portion (32) expands in a direction away from the front disc (2), and the end point of the second expansion portion (32) points to the round chamfer (41).

6. The impeller of the motor according to claim 5, characterized in that: The projection of the inner wall of the first expansion portion (22) on the radial section is a straight line or a smooth curve, and the projection of the inner wall of the second expansion portion (32) on the radial section is a straight line or a smooth curve.

7. The impeller of the motor according to claim 6, characterized in that: The projection of the profile of the inner wall of the first expansion portion (22) on the radial section is an arc, and the extended surface of the inner wall of the first expansion portion (22) forms an obtuse angle with the inner curved wall surface (1).

8. The impeller of the motor according to claim 6, characterized in that: The profile projection of the inner wall of the second expansion portion (32) on the radial section is a circular arc, and the extended surface of the inner wall of the second expansion portion (32) points to the starting point of the round chamfer (41).

9. The impeller of the motor according to claim 5, characterized in that: The axial distance between the starting point of the inner curved wall surface (1) and the starting point of the hub (4) of the stationary impeller is greater than the axial distance between the ending point of the first expansion portion (22) and the ending point of the second expansion portion (32).

10. An axial flow fan, characterized in that: A motor impeller comprising any one of claims 1-9.

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