Backward centrifugal impeller and centrifugal fan

Abstract

The utility model relates to centrifugal fan field provides a kind of rear centrifugal impeller and centrifugal fan, rear centrifugal impeller includes: front disc, rear disc and the multiple blades connected between the front disc and the rear disc;The front disc includes annular main part and the mounting portion protruding from the front end of the main part, the mounting portion is away from the front end of the main part and presents arc extension, along the direction away from the main part, the front end inner diameter of the mounting portion is tapered down.The utility model can solve the defect that the cooperation gap of impeller inlet and current collector is larger in prior art, leading to serious leakage loss, affecting the air volume and efficiency of fan, realize the cooperation gap of impeller inlet and current collector is reduced, reduce leakage loss, improve the overall performance of fan.

Description

Technical Field

[0001] This utility model relates to the field of centrifugal fan technology, and in particular to a backward centrifugal impeller and a centrifugal fan. Background Technology

[0002] The core working principle of a centrifugal fan is to drive an impeller to rotate at high speed using a motor. The centrifugal force generated by the impeller's rotation does work on the gas, allowing it to gain kinetic and pressure energy inside the impeller, thus achieving acceleration and pressurization. Specifically, the gas first enters the fan through a collector, and under the guidance of the collector, flows smoothly towards the impeller inlet. Subsequently, under the centrifugal force of the rotating impeller and the pushing action of the blades, the gas moves along the impeller flow channel towards the impeller outlet, during which its speed and pressure increase. Finally, the high-pressure gas, having completed energy conversion, enters the volute, and after being collected and diffused by the volute, it is discharged from the volute outlet, achieving directional gas delivery.

[0003] However, in the actual operation of centrifugal fans, leakage losses exist, primarily stemming from the gap between the impeller inlet and the collector. Since the impeller inlet area is a low-pressure zone for gas flow, while the volute casing contains gas pressurized by the impeller and is in a relatively high-pressure state, driven by the pressure difference, some of the pressurized gas inside the volute casing flows backward through the gap between the impeller inlet and the collector, returning to the low-pressure zone at the impeller inlet. This reverse leakage not only prevents some of the energy-converted gas from effectively discharging from the volute casing outlet, reducing the actual output air volume of the fan and affecting gas delivery efficiency, but also...

[0004] Existing centrifugal fans generally suffer from a large clearance between the impeller inlet and the collector in their structural design, which has led to the long-standing and unresolved leakage loss problem. Utility Model Content

[0005] This utility model provides a backward centrifugal impeller and a centrifugal fan to solve the defects in the prior art where the large gap between the impeller inlet and the collector leads to serious leakage losses, affecting the air volume and efficiency of the fan. It achieves the goal of reducing the gap between the impeller inlet and the collector, reducing leakage losses, and improving the overall performance of the fan.

[0006] This utility model provides a backward centrifugal impeller, comprising: A front disc, a rear disc, and multiple blades connecting the front disc and the rear disc; The front disc includes an annular main body and a mounting portion that protrudes forward from the front end of the main body. The mounting portion extends in an arc shape away from the front end of the main body, and the inner diameter of the front end of the mounting portion gradually decreases along the direction away from the main body.

[0007] According to the present invention, in a backward centrifugal impeller, the mounting portion extends in an arc shape along a direction away from the main body, and the inner diameter of the mounting portion first increases and then decreases.

[0008] According to the present invention, a backward centrifugal impeller is provided, wherein the mounting part includes a straight section and an arc-shaped section, the mounting part is connected to the main body through the straight section, and the inner diameter of the arc-shaped section gradually decreases.

[0009] According to the present invention, a backward centrifugal impeller is provided, wherein a rounded corner is formed between the mounting part and the main body part.

[0010] According to the present invention, a backward centrifugal impeller has a guide slope on the side of the main body facing the blade, and the guide slope gradually slopes outward along the direction away from the mounting part.

[0011] This utility model also provides a centrifugal fan, including: a collector, a volute, and a backward centrifugal impeller as described above. The collector and the backward centrifugal impeller are both disposed inside the volute and arranged sequentially along the airflow direction.

[0012] According to the present invention, a centrifugal fan is provided, wherein the collector includes an annular assembly portion protruding toward the backward centrifugal impeller, the assembly portion being partially nested inside the mounting portion of the backward centrifugal impeller, the front end of the mounting portion having a first arc-shaped portion, the rear end of the assembly portion having a second arc-shaped portion, and the first arc-shaped portion and the second arc-shaped portion being clearance-fitted.

[0013] According to the present invention, the radius of the first arc-shaped part is R1, the radius of the second arc-shaped part is R2, and the ratio of R1 / R2 is 1.3-1.5.

[0014] According to the present invention, a centrifugal fan is provided, wherein the assembly part includes a contraction section and an expansion section from front to back, the inner diameter of the contraction section gradually decreases, and the inner diameter of the expansion section gradually increases.

[0015] According to the present invention, a centrifugal fan further includes an external rotor motor, wherein the rear disc of the backward centrifugal impeller is mounted on the external rotor of the external rotor motor.

[0016] The backward centrifugal impeller and centrifugal fan provided by this utility model optimize the impeller inlet structure by adopting an arc-shaped structure and a gradually narrowing inner diameter at the front end of the mounting part that cooperates with the collector. Compared with the fixed diameter design of the straight inlet of existing impellers, this effectively reduces the radial gap between the impeller inlet and the collector. This significantly reduces the flow rate of high-pressure gas leaking backward through the gap to the impeller inlet. This not only reduces the loss of pressurized gas and ensures that more gas can be effectively discharged from the outlet of the volute, directly increasing the actual output air volume of the fan, but also avoids airflow interference between leaked gas and normal intake air of the collector at the impeller inlet, reducing additional flow losses caused by airflow impact. This lays the foundation for the impeller's efficient energy conversion of gas, improves the impeller's operational stability, and extends the service life of the equipment.

[0017] The arc-shaped structure of the mounting section also serves as an airflow guide, smoothly guiding the gas entering from the collector and preventing sudden changes or impacts at the inlet. This ensures the airflow enters the impeller channel at a more stable speed and direction. The arc-shaped surface of the mounting section can be adjusted to fit the outlet profile of collectors of different specifications, accommodating minor deviations in the collector outlet dimensions within a certain range and reducing the risk of increased clearance due to machining errors. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a side view of the backward centrifugal impeller provided by this utility model; Figure 2 yes Figure 1 Enlarged schematic diagram of the structure at point A; Figure 3 This is a schematic diagram of the composition structure of the centrifugal fan provided by this utility model; Figure 4 This is a schematic diagram of the internal airflow path of the centrifugal fan provided by this utility model; Figure 5 This is a schematic cross-sectional view of the internal structure of the centrifugal fan provided by this utility model; Figure 6 This is a side view of the current collector provided by this utility model.

[0020] Figure label: 100. Reverse centrifugal impeller; 200. Centrifugal fan; 10. Front plate; 11. Rear plate; 12. Blade; 13. Main body; 14. Mounting part; 141. First section; 142. Second section; 143. First arc-shaped part; 15. Rounded corner; 16. Guide slope; 17. Collector; 18. Volute; 19. Assembly part; 191. Second arc-shaped part; 192. Contraction section; 193. Expansion section; 20. External rotor motor. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0022] In the description of this utility model, it should be understood that the terms "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and 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. Therefore, they should not be construed as limitations on this utility model.

[0023] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0024] In this utility model, unless otherwise expressly specified and limited, the first feature "on" or "below" the second feature may be in direct contact with the first and second features, or indirect contact through an intermediate medium. In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0025] like Figures 1 to 6 As shown, this utility model provides a backward centrifugal impeller 100, comprising: Front disc 10, rear disc 11 and a plurality of blades 12 connecting the front disc 10 and the rear disc 11; The front disc 10 includes an annular main body 13 and a mounting portion 14 protruding forward from the front end of the main body 13. The mounting portion 14 extends in an arc shape away from the front end of the main body 13, and the inner diameter of the front end of the mounting portion 14 gradually decreases along the direction away from the main body 13.

[0026] The existing impeller inlet uses a straight structure, meaning the mounting section of the existing impeller has a uniform inner diameter design, and the collector extends into the inside of the mounting section. The large clearance between the collector and the mounting section leads to significant leakage losses, affecting the fan's airflow and efficiency. To solve these problems, such as... Figure 1 and Figure 2 As shown, this application optimizes the impeller inlet shape. The impeller inlet is formed in the mounting portion 14 of the front disc 10. Along the direction away from the main body 13, the mounting portion 14 includes a first section 141 and a second section 142. The second section 142 has a clearance fit with the collector 17. Because the inner diameter of the second section 142 gradually decreases along the direction away from the main body 13 (i.e., the inner diameter gradually decreases from back to front), forming a tapering structure, compared to the existing straight impeller inlet, the clearance between the second section 142 and the collector 17 can be reduced, thereby reducing leakage losses and improving the fan's airflow and efficiency. Specifically, the second section 142 adopts an arc-shaped structure. The first section 141 can adopt either an arc-shaped structure or a straight structure.

[0027] In one embodiment, the mounting portion 14 extends in an arc shape along a direction away from the main body 13, and the inner diameter of the mounting portion 14 first increases and then decreases. For example... Figure 2As shown in this embodiment, both the first segment 141 and the second segment 142 are arc-shaped structures. Along the gas flow direction, the gas flows through the second segment 142 and the first segment 141 in sequence, forming an expansion segment and a contraction segment respectively. This can enhance the buffering and rectification of the impeller inlet airflow, significantly reduce airflow impact loss, optimize the conversion rhythm of gas kinetic energy and pressure energy, and improve the impeller's working efficiency.

[0028] In another embodiment, the mounting portion 14 includes a straight section and an arc-shaped section. The mounting portion 14 is connected to the main body portion 13 through the straight section, and the inner diameter of the arc-shaped section gradually decreases from back to front. In this embodiment, the first section 141 adopts a straight structure, and the second section 142 adopts an arc-shaped structure. Based on the existing straight inlet structure, only the front half of the mounting portion 14 needs to be improved by machining the front half into an arc shape. The straight section has a regular cylindrical structure, and the machining accuracy is easy to control, enabling rapid prototyping. The arc-shaped section only requires a single tapering curvature design, which is also convenient for machining. The overall process is simplified, and production costs can be reduced.

[0029] Based on the above embodiment, the mounting part 14 and the main body part 13 are smoothly connected by a rounded corner 15. For example... Figure 2 As shown, the rounded corner 15 design guides airflow along a smooth trajectory from the mounting section 14 to the main body 13, avoiding localized flow problems such as eddies and separation, and reducing flow losses. The smooth connection of the rounded corner 15 evenly distributes stress in the connection area through the arc surface, which helps improve the impeller's fatigue resistance. In addition, the smooth connection of the rounded corner 15 has stronger machining tolerance, as the arc transition of the rounded corner 15 can cover machining defects and accommodate minor dimensional errors between the main body 13 and the mounting section 14.

[0030] Based on the above embodiment, the main body 13 has a guide slope 16 on the side facing the blade 12, and the guide slope 16 gradually slopes outward in a direction away from the mounting portion 14. Figure 4 As shown, by setting the guide slope 16, the tilt angle can be designed to match the inlet angle of the blade 12. When the gas flows along the slope, the flow direction is gradually adjusted to the same direction as the inlet angle of the blade 12. This allows the airflow to flow axially from the outlet of the mounting part 14 and smoothly transition to the oblique flow that matches the inlet of the blade 12 after being guided by the slope, thus avoiding direct impact between the airflow and the inlet of the blade 12.

[0031] like Figures 3 to 6As shown, this utility model also provides a centrifugal fan 200, including: a collector 17, a backward centrifugal impeller 100, and a volute 18. The collector 17 and the backward centrifugal impeller 100 are both disposed within the volute 18 and arranged sequentially along the airflow direction. The backward centrifugal impeller 100 adopts the impeller described in the above embodiments and examples. By optimizing the impeller inlet shape and reducing the fitting clearance between the impeller inlet and the collector 17, leakage losses are reduced, thereby improving the fan's airflow and efficiency.

[0032] When the centrifugal fan 200 is working, the gas first enters the fan through the collector 17 and flows smoothly to the impeller inlet under the guidance of the collector 17. Then, the gas entering the impeller moves along the impeller flow channel to the impeller outlet under the centrifugal force of the rotating impeller and the pushing action of the blades 12. During this process, the gas speed and pressure increase. Finally, the high-pressure gas that has completed energy conversion enters the volute 18. After being collected and diffused by the volute 18, it is discharged from the air outlet of the volute 18, realizing the directional transportation of gas.

[0033] In a preferred embodiment of the present invention, the collector 17 includes an annular assembly portion 19 protruding toward the backward centrifugal impeller 100. The assembly portion 19 is partially nested inside the mounting portion 14 of the backward centrifugal impeller 100. The front end of the mounting portion 14 has a first arc-shaped portion 143, and the rear end of the assembly portion 19 has a second arc-shaped portion 191. The first arc-shaped portion 143 and the second arc-shaped portion 191 are in clearance fit.

[0034] Specifically, the first arc-shaped portion 143 gradually narrows its inner diameter along the direction away from the main body portion 13 to form a constricted structure. Compared with the existing straight impeller inlet, the fitting gap between the second arc-shaped portion 191 and the first arc-shaped portion 143 can be reduced, thereby reducing leakage loss and improving the air volume and efficiency of the fan.

[0035] Furthermore, the radius of the first arc-shaped portion 143 is R1, and the radius of the second arc-shaped portion 191 is R2, with R1 / R2 being 1.3-1.5. For example... Figure 5 As shown, by limiting the dimensional relationship between the first arc-shaped portion 143 and the second arc-shaped portion 191, the fitting clearance t between the impeller inlet and the collector 17 can be optimized, preventing the leakage loss from increasing due to a large clearance t, which would affect the air volume and efficiency of the fan. At the same time, it can avoid the problem of the collector 17 being difficult to nest and install due to the excessive contraction of the end of the first arc-shaped portion 143.

[0036] In some embodiments, the assembly portion 19 includes a contraction section 192 and an expansion section 193 from front to back, wherein the inner diameter of the contraction section 192 gradually decreases and the inner diameter of the expansion section 193 gradually increases.

[0037] like Figure 6 As shown, the collector 17, with its varying inner diameter, accelerates the incoming airflow through the contraction section 192. Simultaneously, the guiding surface of the contraction eliminates eddies and deviations in the gas flow, resulting in a uniform axial flow. Then, as the airflow passes through the expansion section 193, its velocity gradually decreases while the pressure increases synchronously, preventing the risk of low-pressure cavitation at the impeller inlet due to a sudden pressure drop. This collector 17, by optimizing the flow channel morphology, significantly reduces pressure loss and improves the overall energy utilization rate of the fan.

[0038] In some embodiments, the centrifugal fan 200 further includes an external rotor motor 20, and the rear disc 11 of the backward centrifugal impeller 100 is mounted on the external rotor of the external rotor motor 20.

[0039] like Figure 4 or Figure 5 As shown, an external rotor motor 20 is used, and the impeller is mounted on the outside of the external rotor via a rear plate 11. This allows the motor and impeller to overlap in the axial direction, significantly reducing the axial volume of the fan and making the fan structure more compact to suit various space-constrained scenarios. The external rotor of the external rotor motor 20 is directly and rigidly connected to the impeller rear plate 11, eliminating intermediate transmission losses, greatly improving the overall energy transfer efficiency, and enhancing operational stability while reducing vibration and noise.

[0040] The backward centrifugal impeller 100 and centrifugal fan 200 provided by this utility model optimize the impeller inlet structure. The front end of the mounting part 14 that cooperates with the collector 17 adopts an arc-shaped structure and a gradually narrowing inner diameter. Compared with the fixed diameter design of the straight inlet of the existing impeller, the radial gap between the impeller inlet and the collector 17 can be effectively reduced. This significantly reduces the flow rate of high-pressure gas leaking backward through the gap to the impeller inlet in the volute 18. This not only reduces the loss of pressurized gas and ensures that more gas can be effectively discharged from the outlet of the volute 18, directly increasing the actual output air volume of the fan, but also avoids the airflow interference formed by the leaked gas and the normal air intake of the collector 17 at the impeller inlet, reducing the additional flow loss caused by airflow impact. This lays the foundation for the impeller's efficient energy conversion of gas, improves the impeller's operating stability, and extends the service life of the equipment.

[0041] The arc-shaped structure of the mounting section 14 also serves as an airflow guide, smoothly guiding the gas entering from the collector 17 and preventing sudden changes or impacts in the airflow at the inlet. This ensures that the airflow enters the impeller channel at a more stable speed and direction. The arc-shaped surface of the mounting section 14 can be adjusted to fit the outlet profile of collectors 17 of different specifications, allowing for minor deviations in the outlet size of the collector 17 within a certain range. This reduces the risk of increased clearance due to machining errors.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A backward centrifugal impeller (100), characterized in that include: Front disc (10), rear disc (11) and multiple blades (12) connecting the front disc (10) and the rear disc (11); The front disc (10) includes an annular main body (13) and a mounting part (14) protruding forward from the front end of the main body (13). The mounting part (14) extends in an arc shape away from the front end of the main body (13), and the inner diameter of the front end of the mounting part (14) gradually decreases along the direction away from the main body (13).

2. The backward centrifugal impeller (100) according to claim 1, characterized in that, Along a direction away from the main body (13), the mounting part (14) extends in an arc shape and the inner diameter of the mounting part (14) first increases and then decreases.

3. The backward centrifugal impeller (100) according to claim 1, characterized in that, The mounting part (14) includes a straight section and an arc section. The mounting part (14) is connected to the main body part (13) through the straight section, and the inner diameter of the arc section gradually decreases.

4. The backward centrifugal impeller (100) according to claim 2 or 3, characterized in that, A rounded corner (15) is formed between the mounting part (14) and the main body part (13).

5. The backward centrifugal impeller (100) according to claim 1, characterized in that, The main body (13) has a flow guide slope (16) on the side facing the blade (12), and the flow guide slope (16) gradually slopes outward in a direction away from the mounting part (14).

6. A centrifugal fan (200) characterized by include: The collector (17), the volute (18), and the backward centrifugal impeller (100) as described in any one of claims 1-5 are provided in the volute (18) and arranged sequentially along the airflow direction.

7. The centrifugal fan (200) according to claim 6, characterized in that, The collector (17) includes an annular assembly portion (19) protruding toward the backward centrifugal impeller (100). The assembly portion (19) is partially nested inside the mounting portion (14) of the backward centrifugal impeller (100). The front end of the mounting portion (14) has a first arc-shaped portion (143), and the rear end of the assembly portion (19) has a second arc-shaped portion (191). The first arc-shaped portion (143) and the second arc-shaped portion (191) are in clearance fit.

8. The centrifugal fan (200) according to claim 7, characterized in that, The radius of the first arc-shaped part (143) is R1, and the radius of the second arc-shaped part (191) is R2, with R1 / R2 being 1.3-1.

5.

9. The centrifugal fan (200) according to claim 7, characterized in that, The assembly part (19) includes a contraction section (192) and an expansion section (193) from front to back. The inner diameter of the contraction section (192) gradually decreases, and the inner diameter of the expansion section (193) gradually increases.

10. The centrifugal fan (200) according to claim 6, characterized in that, Also included is an outer rotor electric motor (20) to which the back disk (11) of the backward centrifugal impeller (100) is mounted on an outer rotor of the outer rotor electric motor (20).

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