Centrifugal fan and motor

Abstract

The centrifugal fan comprises a hub and blades arranged on the hub, the blades extend in the radial direction of the hub, in the radial direction of the hub, each blade comprises an inner end facing the center of the hub and an outer end opposite to the inner end, and in the axial direction of the hub, the outer ends of the inner ends face the center of the hub, and the outer ends of the outer ends face the center of the hub. The outer end comprises a far end far away from the hub and a near end opposite to the far end, the far end is provided with a protruding part, the edge of the protruding part comprises a protruding arc edge and a straight edge, the arc edge is connected with the straight edge, the straight edge is closer to the center of the hub compared with the arc edge, and the outer end of the hub is connected with the protruding part. The purpose of improving the energy efficiency of the motor by improving the structure of the fan blades is achieved.

Description

Technical Field

[0001] This invention belongs to the field of motor technology, specifically relating to a centrifugal fan and its motor. Background Technology

[0002] As national requirements for motor energy efficiency gradually increase, manufacturers are committed to developing motors with energy efficiency of IE4 and above. For motors with self-fan cooling blades, the losses caused by the blades account for more than 10%, greatly affecting the improvement of motor efficiency. The design of the blades must meet the temperature rise requirements, but not be too large, otherwise it will increase the overall windage loss. Therefore, refined blade design is particularly critical.

[0003] How to improve the energy efficiency of motors through the design of fan blades is a technical problem that urgently needs to be solved. Summary of the Invention

[0004] Therefore, the present invention provides a centrifugal fan and motor to improve the energy efficiency of the motor by improving the structure of the fan blades.

[0005] The present invention provides a centrifugal fan, comprising a hub and blades disposed on the hub. The blades extend along the radial direction of the hub. In the radial direction of the hub, the blades include an inner end facing the center of the hub and an opposite outer end. In the axial direction of the hub, the outer end includes a distal end away from the hub and an opposite proximal end. The distal end is provided with a protrusion. The edge of the protrusion includes a raised arc edge and a straight edge. The arc edge is connected to the straight edge, and the straight edge is closer to the center of the hub than the arc edge.

[0006] In some embodiments, in the radial direction of the hub, the proximal end of the blade includes an outer edge portion located radially outside the hub, the edge shape of which includes a bevel directly connected to the hub; the bevel gradually slopes toward the distal end in the direction from the center of the hub toward the outer edge of the hub.

[0007] In some embodiments, the inner edge of the protrusion is located on a circle with the center of the hub as the center and D2 as the diameter, the outer edge of the protrusion is located on a circle with the center of the hub as the center and D1 as the diameter, and the outer edge of the hypotenuse is located on a circle with the center of the hub as the center and D as the diameter. Then: 0.85D≤D1≤0.95D, 0.55D≤D2≤0.7D.

[0008] In some embodiments, in the axial direction of the hub, the height of the protrusion is L1, the height of the inclined side is L2, and the minimum distance between the protrusion and the inclined side is (L-L2), then: 0.15L≤L1≤0.25L, L2≤0.12L.

[0009] In some embodiments, a guide surface is provided at the connection between the blade and the hub.

[0010] In some embodiments, the side of the hub with blades is a pressure surface, and a plurality of guide ribs are provided on the pressure surface; the connection between the guide ribs and the hub is smooth.

[0011] In some embodiments, the guide ribs include: circumferential ribs extending circumferentially along the hub, and / or radial ribs extending radially along the hub.

[0012] In some embodiments, when circumferential ribs and radial ribs are provided, the circumferential ribs are positioned closer to the center of the wheel hub than the radial ribs.

[0013] In some embodiments, when circumferential ribs are provided, a portion of the circumferential ribs are connected between the blade and the hub.

[0014] In some embodiments, the circumferential rib is provided with a through hole that extends through the circumferential rib along the radial direction of the hub.

[0015] The present invention also provides an electric motor, including the centrifugal fan described above.

[0016] By making the aforementioned improvements to the blades, this application provides a protrusion at the far end of the blades, which effectively increases the axial dimension of the blades. Moreover, the increase is only at the outer end, which helps to reduce eddies near the center of the hub, thereby reducing the overall loss when the centrifugal fan rotates. Attached Figure Description

[0017] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the centrifugal fan structure according to an embodiment of the present invention; Figure 2 This is an embodiment of the present invention. Figure 1 Axial schematic diagram; Figure 3This is an embodiment of the present invention. Figure 2 Left sectional view; Figure 4 This is a schematic diagram of a centrifugal fan with radial ribs according to an embodiment of the present invention; Figure 5 This is an embodiment of the present invention. Figure 4 Axial schematic diagram; Figure 6 This is a simulation diagram of the vortex distribution and vortex size generated between two adjacent blades when the centrifugal fan is working according to an embodiment of the present invention. Figure 7 This is a simulation diagram of the distribution and magnitude of eddy currents generated on the radial outer periphery of the centrifugal fan during operation, according to an embodiment of the present invention. Figure 8 This is an axial wind speed cloud map generated by the centrifugal fan during operation according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the first centrifugal fan structure in the prior art; Figure 10 It is existing technology Figure 6 A radial schematic diagram; Figure 11 It is existing technology Figure 7 Axial schematic diagram; Figure 12 It is existing technology Figure 8 A sectional view; Figure 13 This is a simulation diagram of the vortex distribution and vortex size generated between two adjacent blades when a centrifugal fan in the prior art is working. Figure 14 This is the first axial wind speed cloud map generated by a centrifugal fan during operation in the existing technology. Figure 15 This is a schematic diagram of a centrifugal fan with circumferential ribs according to an embodiment of the present invention; Figure 16 This is an axial schematic diagram of a centrifugal fan according to an embodiment of the present invention with circumferential ribs; Figure 17 This is a schematic diagram of a motor with a centrifugal fan in the prior art.

[0019] The attached figures are labeled as follows: 1. Hub; 2. Blade; 201. Inner end; 202. Outer end; 203. Proximal end; 204. Distal end; 205. Protrusion; 206. Arc edge; 207. Straight edge; 208. Outer edge; 209. Bevel edge; 301. Radial rib; 302. Guide groove; 303. Circumferential rib. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0022] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0023] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0024] See also Figure 1-5As shown in Figures 15 and 16, the present invention provides a centrifugal fan, including a hub 1 and blades 2 disposed on the hub 1. The blades 2 extend along the radial direction of the hub 1. In the radial direction of the hub 1, the blades 2 include an inner end 201 facing the center of the hub 1 and an opposite outer end 202. In the axial direction of the hub 1, the outer end 202 includes a distal end 204 away from the hub 1 and an opposite proximal end 203. The distal end 204 is provided with a protrusion 205. The edge of the protrusion 205 includes a raised arc edge 206 and a straight edge 207. The arc edge 206 is connected to the straight edge 207. The straight edge 207 is closer to the center of the hub 1 than the arc edge 206.

[0025] Specifically, such as Figure 1-5 As shown, in the axial direction of hub 1, the improvements of this application (such as...) Figure 3 ) is in the existing wind turbine blades (such as Figure 12 It is an improvement based on the previous one. The side of the blade 2 away from the hub 1 includes a protrusion 205 and a straight section (such as...). Figure 3 As shown), the straight section connects the rotation center of the hub 1 and the protrusion 205. The rotation center of the hub 1 has a shaft hole, and a cylinder surrounds the shaft hole. The straight section is connected to the cylinder. The distal end 204 is the protrusion 205. The edge shape of the protrusion 205 includes a raised arc edge 206 and a straight edge 207. The arc edge 206 is connected to the straight edge 207, and the straight edge 207 is closer to the center of the hub 1 than the arc edge 206. This application improves the blade 2 by providing the protrusion 205 at the distal end 204 of the blade 2, effectively increasing the axial dimension of the blade 2. This increase is only at the outer end 202, which helps reduce eddies near the center of the hub 1, thereby reducing the overall loss when the centrifugal fan rotates. Simulation results show that... Figure 7 and Figure 8 As shown, the effective section for airflow driven by the rotation of blade 2 is concentrated on the outer diameter side (outer end 202). From the vortex of each cross section of blade 2, the wider blade 2 (axial dimension), the more obvious the vortex. Thus, by retaining the effective blade height (outer end 202 dimension) and reducing the width of the lower part of blade 2 (inner end 201), the vortex loss between blades 2 can be reduced. This application can ensure that the air volume is effectively increased while the loss is basically not increased through the protrusion.

[0026] Compared to existing fan blades, the blade 2 of this application experiences less wear, and the loss of blade 2 is reduced by about 30%. When applied to motors, it effectively improves motor efficiency.

[0027] Preferred, such as Figure 3As shown, in the radial direction of the hub 1, the proximal end 203 of the blade 2 includes an outer edge portion 208 located radially outside the hub 1, and the edge shape of the outer edge portion 208 includes a chamfer 209 directly connected to the hub 1; in the direction from the center of the hub 1 to the outer edge of the hub 1, the chamfer 209 gradually slopes towards the distal end 204.

[0028] The centrifugal fan rotates inside the motor. External air enters the motor axially and undergoes centrifugal motion driven by blades 2. The air flows radially outwards, contacting the fan shroud and then flowing towards the end of the casing. The wind speed reaches its maximum near the outer end 202 (near the end 203) of blade 2. Conventional fan blades exhibit a wind speed discontinuity between the blade tail and the end cover. Figure 6 As shown, the inclined side 209 in this application can reduce the channel of rotating air volume, reduce the vortex situation at high wind speed, and enhance the continuity of the transmission process of blade 2, which has a better effect on reducing the temperature rise of the motor.

[0029] Figure 13 and Figure 14 This refers to the airflow pattern when an existing centrifugal fan is operating; Figure 6 , Figure 7 and Figure 8 This describes the airflow pattern when the centrifugal fan of this application is operating. Specifically, from... Figure 6 and Figure 13 The comparison clearly shows that the optimized centrifugal fan of this application generates significantly fewer eddies, improving blade efficiency and reducing losses and noise. From the optimized... Figure 7 , Figure 8 and existing technology Figure 14 The comparison shows that the airflow exiting from the outer edge of the centrifugal fan is significantly faster; and Figure 14 The existing technology in this application has a fan breakage at the tail end of the fan blade and the center line of the end cover, while this application... Figure 8 In this system, the overall wind speed uniformity and continuity are better, eddies are reduced, and correspondingly, eddy loss is also reduced.

[0030] Preferred, such as Figure 3 As shown, the inner edge of the protrusion 205 is located on a circle with the center of the hub 1 as the center and D2 as the diameter, the outer edge of the protrusion 205 is located on a circle with the center of the hub 1 as the center and D1 as the diameter, and the outer edge of the inclined side 209 is located on a circle with the center of the hub 1 as the center and D as the diameter. Therefore: 0.85D≤D1≤0.95D, 0.55D≤D2≤0.7D.

[0031] like Figure 6 Figure 7 and Figure 8As shown in the simulation test, when 0.85D≤D1≤0.95D and 0.55D≤D2≤0.7D, the air volume output by blade 2 is relatively large, while the energy consumption does not increase significantly.

[0032] Preferred, such as Figure 3 As shown, in the axial direction of the hub 1, the height of the protrusion 205 is L1, the height of the inclined side 209 is L2, and the minimum distance between the protrusion 205 and the inclined side 209 is (L-L2). Therefore, 0.15L≤L1≤0.25L, L2≤0.12L.

[0033] like Figure 6 Figure 7 and Figure 8 As shown in the simulation test, the position (the reduced blade 2 in the diagonal area) should not be too large, otherwise it will reduce the effective area of ​​the wind turbine blade. Preferably, L2≤0.12L.

[0034] Preferred, such as Figure 3 As shown, a guide surface is provided at the connection between the blade 2 and the hub 1.

[0035] By setting the guide surface, the vortex generated at the connection between the hub 1 and the blade 2 when the airflow flows in the area between two adjacent blades 2 is smaller. This helps to ensure the stable rotation of the centrifugal fan, facilitates the rapid flow of airflow, and avoids the vibration and noise generated by the turbine.

[0036] In other words, the connection area between the root of blade 2 and hub 1 adopts a circular arc transition structure. The transition radius is optimized based on the airflow simulation results, making the airflow in this area smoother and avoiding airflow separation caused by geometric abrupt changes.

[0037] Preferred, such as Figure 4 and Figure 5 As shown, the side of the hub 1 with the blades 2 is a pressure surface, and multiple guide ribs are provided on the pressure surface; the connection between the guide ribs and the hub 1 is smooth.

[0038] By setting guide ribs, the airflow is smoother when flowing between two adjacent blades 2, reducing airflow turbulence; the guide ribs can reduce the formation of vortices and have a breaking effect on larger vortices, improving the fluidity of the airflow.

[0039] Preferred, such as Figure 3 , Figure 15 and Figure 16 As shown, the guide ribs include: circumferential ribs 303 extending circumferentially along the hub 1, and / or radial ribs 301 extending radially along the hub 1.

[0040] like Figure 15 and Figure 16 As shown, the circumferential ribs 303 help to break up large vortices generated by airflow, preventing their formation. This implementation is suitable for low-speed motor operation. When both the motor and centrifugal fan speeds are low, the resulting vortices significantly impact the vibration of the blades 2. By using the circumferential ribs 303, the vortices are effectively broken up or reduced. The circumferential ribs 303 also allow some airflow to flow circumferentially, impacting the connection between the blades 2 and hub 1. This causes the airflow to collide with and break up the vortices at the connection, reducing their size and improving airflow flow.

[0041] The radial ribs 301 are designed to guide the airflow and accelerate the flow of air out between the two blades 2, which helps to increase the air volume. At the same time, the radial ribs 301 can also break up vortices and reduce the impact of vortices on the airflow.

[0042] The circumferential ribs 303 and radial ribs 301 are set simultaneously to break up vortices and comprehensively consider airflow to achieve greater airflow, less vibration, and less noise.

[0043] Furthermore, multiple circumferential ribs 303 and radial ribs 301 are provided, evenly distributed along the circumference of the hub 1.

[0044] An annular guide groove 302 is formed between the circumferential ribs 303 provided at the bottom of the channel between two adjacent blades 2 (on the hub 1), and a radial guide groove 302 is formed between the radial ribs 301. The guide grooves 302 extend along the rotation direction of the blades 2 to form a continuous airflow guide channel.

[0045] Furthermore, the guide channel 302 is a segmented guide channel 302 structure, with the guide channels 302 arranged alternately along the radial direction of the fan blade, such as... Figure 5 As shown, airflow between blades 2 can be achieved through the staggered gaps between the guide grooves 302. These staggered gaps can also be adjusted according to different airflow velocities (required for different operating conditions) to meet the actual needs of different speed scenarios (operating conditions) and further optimize the guiding effect. Simultaneously, the guide grooves 302 can effectively guide the airflow generated at the junction of the blade root and hub 1, preventing the formation of vortices, thereby reducing energy loss and noise.

[0046] The blade 2 is made of high-strength, lightweight materials to balance structural strength and weight control.

[0047] Preferably, when circumferential ribs 303 and radial ribs 301 are provided, the circumferential ribs 303 are positioned closer to the center of the hub 1 than the radial ribs 301.

[0048] When air flows between two adjacent blades 2, the closer to the center of the hub 1, the lower the airflow velocity and the smaller the air volume. By positioning the circumferential ribs 303 closer to the center of the hub 1 than the radial ribs 301, the smaller airflow velocity and air volume are minimized or reduced by the circumferential ribs 303. This prevents the vortices generated near the center of the hub 1 from interfering with the larger airflow velocity and volume in the area away from the center of the hub 1, thus improving airflow velocity and volume. Conversely, the radial ribs 301 in the area away from the center of the hub 1 accelerate airflow, allowing it to leave the centrifugal fan more quickly. The faster the airflow, the more pronounced the suction effect of the centrifugal fan's rotation, increasing the flow rate entering the centrifugal fan and further improving the centrifugal fan's output air volume.

[0049] Preferred, such as Figure 4 and Figure 5 As shown, when circumferential ribs 303 are provided, a portion of the circumferential ribs 303 are connected between the blade 2 and the hub 1.

[0050] The circumferential rib 303 connects the blade 2 and the hub 1. On the one hand, it increases the structural rigidity of the blade 2 on the hub 1, reduces the vibration amplitude of the blade 2 under airflow impact, which is beneficial to improving the stability of airflow and reducing vibration noise. On the other hand, the connection between the blade 2 and the hub 1 is prone to generating strip-shaped vortices extending along the connection. The circumferential rib 303 helps to break up these strip-shaped vortices, which is beneficial to airflow.

[0051] Preferably, the circumferential rib 303 is provided with a through hole, which penetrates the circumferential rib 303 along the radial direction of the hub 1.

[0052] By providing through holes in the circumferential ribs 303, some airflow flows through the through holes, which allows the circumferential ribs 303 to break up the turbine while reducing the resistance to airflow.

[0053] The present invention also provides an electric motor, including the centrifugal fan.

[0054] Currently, the most common cooling fan blades for industrial motors are centrifugal fan blades, with a structure as follows: Figures 9-12As shown, the shape of blade 2 is usually a square blade with chamfered corners. The main influence on airflow is the blade size, which is the outer diameter D, the blade width L (since the blade 2 in this application is an improvement on the existing blade, the outer diameter D and the blade width L here have the same meaning as D and L in this application), the blade height H, the number of blades N, the blade shape, and the disc shape. This blade design was initially applied to motors such as the Y2 series, where the overall energy efficiency of the motor is around IE3, with low energy efficiency requirements. It lacked a detailed design of the blade position. Fluid CFD simulation analysis showed that the blade width was relatively wide, the height was uniform, and the eddy currents between the blades were severe, which greatly increased the motor losses. When conventional blades are applied to motors with energy efficiency of IE4 or higher, their wind wear losses are too high, making it difficult to meet the requirements for further improving the energy efficiency of the motor.

[0055] By using the centrifugal fan described above, the airflow into the motor is effectively increased. This increased airflow helps reduce the overall temperature rise of the motor, thereby improving motor performance, reducing motor operating noise, and extending the motor's service life.

[0056] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A centrifugal fan, comprising a hub (1) and blades (2) disposed on the hub (1), the blades (2) extending along the radial direction of the hub (1), wherein, in the radial direction of the hub (1), the blades (2) include an inner end (201) facing the center of the hub (1) and an opposite outer end (202), and in the axial direction of the hub (1), the outer end (202) includes a distal end (204) remote from the hub (1) and an opposite proximal end (203), characterized in that, The distal end (204) is provided with a protrusion (205), the edge of which includes a raised arc edge (206) and a straight edge (207). The arc edge (206) is connected to the straight edge (207), and the straight edge (207) is closer to the center of the hub (1) than the arc edge (206).

2. The centrifugal fan according to claim 1, characterized in that, In the radial direction of the hub (1), the proximal end (203) of the blade (2) includes an outer edge (208) located radially outside the hub (1), the edge shape of which includes a chamfer (209) directly connected to the hub (1); the chamfer (209) gradually slopes toward the distal end (204) in the direction from the center of the hub (1) toward the outer edge of the hub (1).

3. The centrifugal fan according to claim 2, characterized in that, The inner edge of the protrusion (205) is located on a circle with the center of the hub (1) as the center and D2 as the diameter. The outer edge of the protrusion (205) is located on a circle with the center of the hub (1) as the center and D1 as the diameter. The outer edge of the hypotenuse (209) is located on a circle with the center of the hub (1) as the center and D as the diameter. Therefore: 0.85D≤D1≤0.95D, 0.55D≤D2≤0.7D.

4. The centrifugal fan according to claim 2, characterized in that, In the axial direction of the hub (1), the height of the protrusion (205) is L1, the height of the inclined side (209) is L2, and the minimum distance between the protrusion (205) and the inclined side (209) is (L-L2). Therefore: 0.15L≤L1≤0.25L, L2≤0.12L.

5. The centrifugal fan according to claim 1, characterized in that, A flow guide surface is provided at the connection between the blade (2) and the hub (1).

6. The centrifugal fan according to any one of claims 1-5, characterized in that, The hub (1) has a pressure surface on one side where the blades (2) are provided, and multiple guide ribs are provided on the pressure surface; the connection between the guide ribs and the hub (1) is smooth.

7. The centrifugal fan according to claim 6, characterized in that, The guide ribs include: circumferential ribs (303) extending circumferentially along the hub (1), and / or radial ribs (301) extending radially along the hub (1).

8. The centrifugal fan according to claim 7, characterized in that, When circumferential ribs (303) and radial ribs (301) are provided, the circumferential ribs (303) are positioned closer to the center of the hub (1) than the radial ribs (301).

9. The centrifugal fan according to claim 7, characterized in that, When circumferential ribs (303) are provided, a portion of the circumferential ribs (303) are connected between the blade (2) and the hub (1).

10. The centrifugal fan according to claim 9, characterized in that, The circumferential rib (303) is provided with a through hole, which penetrates the circumferential rib (303) along the radial direction of the hub (1).

11. An electric motor, characterized in that, Includes the centrifugal fan as described in any one of claims 1-10.

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