A high-efficiency and low-noise fan shroud and its guide ring wall profile fitting system

Abstract

The present invention discloses a high-efficiency and low-noise fan shroud, comprising a centrifugal fan synchronously mounted on a rotor shaft at the rear end of a motor heat dissipation housing, wherein an annular wall-shaped wind shell is arranged outside the centrifugal fan; a centrifugal air cavity is formed inside the annular wall-shaped wind shell; the annular wall-shaped wind shell comprises an air inlet section annular wall, a flow guide section annular wall and an air outlet section annular wall in sequence along the axial direction; the cross-sectional contour line of the flow guide section annular wall is in an arc shape convex toward a side away from the centrifugal air cavity; the air outlet section annular wall is in a cylindrical shape at the outer periphery of the rear end of the motor heat dissipation housing, so that an annular air outlet is formed between the air outlet section annular wall and the outer periphery of the rear end of the motor heat dissipation housing; compared with the existing wind shell with a broken line cross-sectional contour, it has the characteristics of small wind friction loss and higher air cooling efficiency.

Description

Technical Field

[0001] The present invention relates to the field of motor fan covers. Background Art

[0002] During the operation of the motor, the wind wear of the fan seriously affects the efficiency of the motor. NEMA motors have high requirements for efficiency and noise. A good fan and wind cover can effectively reduce motor noise and improve motor efficiency. The original fan and wind cover structure is as follows: Figure 1 As shown;

[0003] A centrifugal fan is used, and the wind is sucked in from outside the wind cover, dispersed to all sides through the centrifugal fan, hitting the wall and inclined surface of the wind cover, and then blown forward along the inclined surface and wall, and finally enters the gap between the heat sink fins of the base.

[0004] The disadvantages of this structure are: first, the centrifugal fan is noisy, and second, the wind is straight. From the perspective of fluid mechanics, there is no smooth flow guidance, and the loss is large, resulting in reduced air volume, low cooling efficiency, and increased heat loss. Therefore, it is necessary to design an efficient fan hood structure with smooth flow guidance capability, as well as a test tool for finding the optimal hood contour of this efficient hood and a corresponding contour curve fitting method. Summary of the invention

[0005] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a high-efficiency and low-noise fan shroud and its guide ring wall profile fitting system, which has the characteristics of less wind friction loss and higher air cooling efficiency compared to the existing broken line cross-section profile wind shell.

[0006] Technical solution: To achieve the above-mentioned purpose, the present invention provides a high-efficiency and low-noise fan hood, comprising a centrifugal fan synchronously mounted on the rotor shaft at the rear end of the motor heat dissipation housing, and an annular wall-shaped wind shell is arranged outside the centrifugal fan;

[0007] A centrifugal air cavity is formed inside the annular wall-shaped wind shell; the annular wall-shaped wind shell includes an air inlet section annular wall, a flow guide section annular wall and an air outlet section annular wall in sequence along the axial direction;

[0008] The cross-sectional contour line of the annular wall of the guide section is in the shape of an arc convex toward the side away from the centrifugal air cavity;

[0009] The annular wall of the air outlet section is cylindrically shaped at the outer periphery of the rear end of the motor heat dissipation shell, so that an annular air outlet is formed between the annular wall of the air outlet section and the outer periphery of the rear end of the motor heat dissipation shell.

[0010] Furthermore, the cross-sectional profile of the annular wall of the air inlet section is in the shape of an arc convex toward one side of the centrifugal fan, and is adapted to the outer cross-sectional profile of the wind wheel of the centrifugal fan, and a gap is maintained.

[0011] A guide ring wall contour fitting system for a high-efficiency and low-noise fan shroud, comprising a ring wall-shaped wind shell for experiments;

[0012] The experimental annular wall-shaped wind shell encloses the outer periphery of the centrifugal fan on the rotor shaft at the rear end of the motor heat dissipation housing; the experimental annular wall-shaped wind shell includes an air inlet section annular wall, a conical elastic guide section annular wall and an air outlet section annular wall in sequence along the axial direction; the air inlet section annular wall and the air outlet section annular wall are both hard structures.

[0013] Furthermore, the outer peripheral seal of the conical elastic guide section ring wall surrounds the air chamber box body, the front wall of the air chamber box body and the inner ring are integrated and sealed to the outer wall surface of the outlet section ring wall; the rear wall of the air chamber box body and the inner ring are integrated and sealed to the outer wall surface of the inlet section ring wall; the air chamber box body contains a variable air pressure chamber.

[0014] Furthermore, there is an air pressure sensor in the variable air pressure chamber.

[0015] Furthermore, the rear wall of the box body is provided with an air nozzle connected to the variable air pressure chamber.

[0016] Furthermore, a number of vertical hollow tubes are fixed at the upper end of the air chamber box in an equidistant array along the axial direction, and the lower end of each vertical hollow tube is connected to the variable air pressure chamber; an electromagnet is sealed and fixedly provided at the upper end of each vertical hollow tube; a benchmark is provided in each vertical hollow tube along the length direction, and the lengths of the benchmarks are the same. The upper end of each benchmark has a magnetic material section that can be attracted by the electromagnet in the energized state. In the initial state, each electromagnet is energized and attracts the magnetic material section at the upper end of each benchmark.

[0017] Furthermore, the vertical hollow tube is made of a transparent material with height scale lines or the vertical hollow tube is provided with a height sensor capable of recording the height of the upper end of the internal benchmark.

[0018] Furthermore, a wind speed sensor is arranged at the annular air outlet formed between the annular wall of the air outlet section and the outer periphery of the rear end of the motor heat dissipation housing.

[0019] Furthermore, the centrifugal fan at the rear of the motor rotates at a desired speed; the air pressure sensed by the air pressure sensor in the variable air pressure chamber is represented by p, and the wind speed sensed by the wind speed sensor arranged at the annular air outlet is represented by v, and a pv coordinate system is established;

[0020] The air pressure P1 in the variable air pressure chamber is gradually increased to p4; the pv coordinate system forms a p vs. v variation relationship curve in the interval from p1 to p4, and there is a v peak value Vm on the p vs. v variation relationship curve; the p value corresponding to the peak value Vm is recorded as p2, and the convex elastic guide section ring wall when the p value is p2 is recorded as the target shape elastic guide section ring wall 5;

[0021] When the air pressure p in the variable air pressure chamber reaches p2 and remains stable, the elastic guide section annular wall 5 of the target shape is formed;

[0022] All electromagnets are controlled to be de-energized, and then the endpoints of the upper ends of several benchmarks are fitted with curves to obtain a final fitting curve; the obtained fitting curve is exactly the cross-sectional contour line of the ring wall of the elastic guide section of the target shape.

[0023] Beneficial effect: The annular wall-shaped wind shell structure with an arc-shaped cross-sectional profile of the present invention is relatively Figure 1 The wind shell with a broken-line cross-section profile has the characteristics of small wind friction loss and higher air cooling efficiency.

[0024] The guide ring wall contour fitting system of the high-efficiency and low-noise fan shroud based on this case can obtain the wind shell contour fitting curve with the best fan efficiency, and the cross-sectional contour line of the guide section ring wall of the ring wall-shaped wind shell is designed to be consistent with the fitting curve; thereby finally obtaining a ring wall-shaped wind shell structure that makes the centrifugal fan's air cooling efficiency higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Attached Figure 1 It is a schematic diagram of the existing fan and wind casing structure;

[0026] Attached Figure 2 This is a schematic diagram of the fan and wind casing structure finally obtained by this scheme;

[0027] Attached Figure 3 For attachment Figure 2 A more detailed structural diagram based on the

[0028] Attached Figure 4 It is a structural schematic diagram of the guide ring wall profile fitting system in the initial state;

[0029] Attached Figure 5 For attachment Figure 4 A partial enlarged schematic diagram of the upper part;

[0030] Attached Figure 6 It is a cross-sectional view of a single vertical hollow tube;

[0031] Attached Figure 7 The figure is a curve fitting diagram of the flow guide contour of the ring wall of the elastic flow guide section with a target shape;

[0032] Attached Figure 8 It is a three-dimensional schematic diagram of the guide ring wall profile fitting system;

[0033] Attached Fig. 9 is the coordinate system in which p changes with v. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings.

[0035] As attached Figure 2 and 3The high-efficiency and low-noise fan hood shown in the figure comprises a motor heat dissipation housing 1 outside the motor stator and rotor, and a plurality of heat dissipation fins 2 are distributed outside the motor heat dissipation housing 1; a centrifugal fan 10 is synchronously installed on the rotor shaft 8 at the rear end of the motor heat dissipation housing 1, and an annular wall-shaped wind housing 14 is arranged outside the centrifugal fan 10; the annular wall-shaped wind housing 14 is fixed to the motor heat dissipation housing 1 through a fixing member; an annular air outlet 3 is formed between the inner wall of the annular wall-shaped wind housing 14 close to one end of the motor heat dissipation housing 1 and the outer ring of the rear end of the motor heat dissipation housing 1; a centrifugal air cavity 11 is formed inside the annular wall-shaped wind housing 14; the rear end of the annular wall-shaped wind housing 14 is fixedly covered with a dust cover 9, as shown in FIG. Figure 8 , the dust cover 9 has an air intake mesh 15; Figure 3 The annular wall-shaped wind shell 14 includes an air inlet section annular wall 6, a guide section annular wall 5 and an air outlet section annular wall 4 in sequence along the axial direction; the cross-sectional profile of the air inlet section annular wall 6 is an arc-shaped convex to one side of the centrifugal fan 10, and is adapted to the outer cross-sectional profile 7 of the wind wheel of the centrifugal fan 10, and a gap is maintained; the cross-sectional profile of the guide section annular wall 5 is an arc-shaped convex to the side away from the centrifugal air cavity 11; the air outlet section annular wall 4 is cylindrical and arranged at the outer periphery of the rear end of the motor heat dissipation housing 1, so that an annular air outlet 3 is formed between the air outlet section annular wall 4 and the outer periphery of the rear end of the motor heat dissipation housing 1; the structure of the annular wall-shaped wind shell 14 with an arc-shaped cross-sectional profile in this case is different from the existing Figure 1 The wind shell with a broken-line cross-section profile has the characteristics of small wind friction loss and higher air cooling efficiency.

[0036] Theoretically, there is an optimal cross-sectional arc contour line for the guide section annular wall 5 of the annular wall-shaped wind shell 14. Under this optimal cross-sectional arc contour line, the air cooling efficiency of the centrifugal fan 10 can be higher. In this solution, the optimal line shape of the cross-sectional contour line of the guide section annular wall 5 of the annular wall-shaped wind shell 14 is obtained by the following device and method system, as follows:

[0037] like Figures 3 to 9 The guide ring wall contour fitting system of a high-efficiency and low-noise fan shroud is shown in FIG. Figure 3 Designed on the basis of structure.

[0038] like Figure 4 , including the experimental annular wind shell 14, and Figure 3 Same, like Figure 4 The annular wall-shaped wind shell 14 used in the experiment encloses the outer periphery of the centrifugal fan 10 on the rotor shaft 8 at the tail end of the motor heat dissipation housing 1; the annular wall-shaped wind shell 14 used in the experiment and Figure 3 , the difference is that the conical elastic guide section ring wall 5a, such as Figure 4The ring-walled wind shell 14 used in the experiment includes an air inlet section ring wall 6, a conical elastic guide section ring wall 5a and an air outlet section ring wall 4 in the axial direction; the air inlet section ring wall 6 and the air outlet section ring wall 4 are both hard structures; the conical elastic guide section ring wall 5a is made of high-toughness elastic rubber or latex.

[0039] like Figure 4 The outer periphery of the conical elastic guide section annular wall 5a is sealed and surrounded by an air chamber box 17, the inner circle of the front wall 17.1 of the air chamber box 17 is integrally sealed and connected to the outer wall of the outlet section annular wall 4; the inner circle of the rear wall 17.2 of the air chamber box 17 is integrally sealed and connected to the outer wall of the inlet section annular wall 6; the air chamber box 17 contains a variable air pressure chamber 16; the variable air pressure chamber 16 contains an air pressure sensor; the rear wall 17.2 of the box is provided with an air nozzle 19 connected to the variable air pressure chamber 16, and also includes an exhaust device and a boosting device, the exhaust device can exhaust the air in the variable air pressure chamber 16 through the air nozzle 19, and the boosting device can pressurize external gas into the variable air pressure chamber 16 through the air nozzle 19.

[0040] A plurality of vertical hollow tubes 18 are fixed to the upper end of the air chamber box 17 in an equidistant array along the axial direction. Figure 6 , the lower end of each vertical hollow tube 18 is connected to the variable air pressure chamber 16; the upper end of each vertical hollow tube 18 is sealed and fixed with an electromagnet 190; a benchmark 21 is arranged in the length direction of each vertical hollow tube 18, and the length of each benchmark 21 is the same. The upper end of each benchmark 21 has a magnetic material section 20 that can be attracted by the electromagnet 190 in the energized state. In the initial state, each electromagnet 190 is energized and attracts the magnetic material section 20 at the upper end of each benchmark 21; except for the magnetic material section 20, the rest of the benchmark 21 is made of lightweight materials, so that the total weight of each benchmark 21 is relatively light; the vertical hollow tube 18 is a transparent material with a height scale line or the vertical hollow tube 18 has a height sensor that can record the upper end height of the internal benchmark 21; a wind speed sensor is arranged at the annular air outlet 3 formed between the air outlet section ring wall 4 and the outer periphery of the tail end of the motor heat dissipation housing 1.

[0041] The process of finding and fitting the appropriate contour of the guide ring wall:

[0042] The variable air pressure chamber 16 is evacuated and supplied with air through the air nozzle 19 by the air extraction device and the booster device, and the air pressure sensor in the variable air pressure chamber 16 cooperates to freely control the air pressure in the variable air pressure chamber 16; during the test, the motor always runs stably at a predetermined speed, and the centrifugal fan 10 at the rear of the motor rotates at the expected rated speed following the rotor shaft 8 of the motor;

[0043] Assume that the air pressure sensed by the air pressure sensor in the variable air pressure chamber 16 is represented by p, and the wind speed sensed by the wind speed sensor arranged at the annular air outlet 3 is represented by v. In theory, the larger the value of v, the better the cooling intensity of the fan. The pv coordinate system is established; Fig. 9 As shown;

[0044] The experimental steps to find the most suitable contour of the flow-guiding ring wall are as follows:

[0045] Step 1: Let p3 be the standard atmospheric pressure. In the initial state, control the air pressure in the variable air pressure chamber 16 to be P1, P1<p3. When the air pressure in the variable air pressure chamber 16 is P1 under the strong negative pressure state, the air pressure in the centrifugal air chamber 11 is higher than the air pressure in the variable air pressure chamber 16. The conical elastic guide section ring wall 5a bulges toward one side of the variable air pressure chamber 16 under the action of the air pressure difference between the inner centrifugal air chamber 11 and the outer variable air pressure chamber 16, so that the conical elastic guide section ring wall 5a is deformed into an outward convex elastic guide section ring wall 5c and forms a stable shape.

[0046] Step 2, such as Figure 5 As shown, on the basis of the end of "step one", the air pressure in the variable air pressure chamber 16 is slowly and gradually increased, so that the air pressure difference between the centrifugal air chamber 11 and the variable air pressure chamber 16 is gradually reduced, and the convexity of the outward convex elastic guide segment ring wall 5c is gradually reduced. As the air pressure in the variable air pressure chamber 16 continues to increase to exceed the air pressure in the centrifugal air chamber 11, the original outward convex elastic guide segment ring wall 5c bulges toward the side of the centrifugal air chamber 11 under the action of the air pressure difference between the centrifugal air chamber 11 and the variable air pressure chamber 16, so that the original outward convex elastic guide segment ring wall 5c is changed into an inward convex elastic guide segment ring wall 5b, until the air pressure in the variable air pressure chamber 16 increases to p4, at which time p4 is greater than p3;

[0047] Step 3, in the process of "Step 2", the pv coordinate system forms a p vs. v variation relationship curve 80 in the interval from p1 to p4, and there is a v peak value Vm on the p vs. v variation relationship curve 80; the p value corresponding to the peak value Vm is recorded as p2, and in practice p1<p2<p3; it means that under the same conditions, when the p value is p2, the annular air outlet 3 obtains the maximum wind speed and achieves the best cooling effect; the convex elastic guide section ring wall 5c when the p value is p2 is recorded as the target shape elastic guide section ring wall 5d;

[0048] Step 4: Control the value of the air pressure p in the variable air pressure chamber 16 to p2 and maintain it stable. At this time, the elastic guide section ring wall 5d of the target shape is just formed;

[0049] Step 5: Control all the electromagnets 190 to be powered off, so that the markers 21 in each vertical hollow tube 18 automatically fall down under the action of gravity until the lower end of each marker 21 is supported by the outer contour of the elastic guide section ring wall 5d of the target shape; at this time, the endpoints of the upper ends of several markers 21 are recorded by the height scale lines on each transparent vertical hollow tube 18, and then the endpoints of the upper ends of several markers 21 are fitted with a curve to obtain a final fitting curve 31; the obtained fitting curve 31 is exactly the cross-sectional contour line of the elastic guide section ring wall 5d of the target shape;

[0050] Step 6: When manufacturing the final annular wall-shaped wind shell 14 product, based on the fitting curve 31 obtained in "Step 5", the cross-sectional contour line of the guide section annular wall 5 of the annular wall-shaped wind shell 14 is designed to be consistent with the fitting curve 31; thereby finally obtaining an annular wall-shaped wind shell 14 structure that makes the air cooling efficiency of the centrifugal fan 10 higher. The final annular wall-shaped wind shell 14 product is as follows: Figure 3 shown.

[0051] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high-efficiency and low-noise fan shroud guide ring wall profile fitting system, characterized by: It includes an annular wind shell (14) for use in the experiment; The experimental annular wall-shaped wind casing (14) encloses the outer periphery of the centrifugal fan (10) on the rotor shaft (8) at the rear end of the motor heat dissipation casing (1); the experimental annular wall-shaped wind casing (14) includes, in sequence along the axial direction, an air inlet section annular wall (6), a conical elastic flow guide section annular wall (5a), and an air outlet section annular wall (4); both the air inlet section annular wall (6) and the air outlet section annular wall (4) are hard structures; The outer periphery of the conical elastic guide section annular wall (5a) is sealed to surround an air chamber box (17); the inner circle of the front wall (17.1) of the air chamber box (17) is integrally sealed to connect to the outer wall of the outlet section annular wall (4); the inner circle of the rear wall (17.2) of the air chamber box (17) is integrally sealed to connect to the outer wall of the inlet section annular wall (6); the air chamber box (17) contains a variable air pressure chamber (16); The rear wall (17.2) of the box body is provided with an air nozzle (19) communicating with the variable air pressure chamber (16); A plurality of vertical hollow tubes (18) are fixed at the upper end of the air chamber box (17) in an equidistant array along the axial direction, and the lower end of each of the vertical hollow tubes (18) is connected to the variable air pressure chamber (16); an electromagnet (190) is sealed and fixedly provided at the upper end of each of the vertical hollow tubes (18); a rod (21) is provided inside each of the vertical hollow tubes (18) along the length direction, and the lengths of the rods (21) are the same. The upper end of each of the rods (21) has a magnetic material section (20) that can be attracted by the electromagnet (190) in an energized state. In the initial state, each of the electromagnets (190) is energized and attracts the magnetic material section (20) at the upper end of each of the rods (21); The vertical hollow tube (18) is made of a transparent material with height scale lines or a height sensor capable of recording the upper end height of the internal benchmark (21) is provided on the vertical hollow tube (18).

2. The guide ring wall contour fitting system of a high-efficiency and low-noise fan shroud according to claim 1 is characterized in that: A wind speed sensor is arranged at the annular air outlet (3) formed between the air outlet section annular wall (4) and the outer periphery of the rear end of the motor heat dissipation housing (1).

3. The guide ring wall contour fitting system of a high-efficiency and low-noise fan shroud according to claim 2 is characterized in that: The centrifugal fan (10) at the rear of the motor rotates at a desired speed; the air pressure sensed by the air pressure sensor in the variable air pressure chamber (16) is represented by p, and the wind speed sensed by the wind speed sensor arranged at the annular air outlet (3) is represented by v, and a pv coordinate system is established; The air pressure p1 in the variable air pressure chamber (16) is gradually increased to p4; the pv coordinate system forms a p vs. v variation relationship curve (80) in the interval from p1 to p4, and there is a v peak value Vm on the p vs. v variation relationship curve (80); the p value corresponding to the peak value Vm is recorded as p2, and the outward convex elastic guide section ring wall (5c) when the p value is p2 is recorded as the target shape elastic guide section ring wall (5d); The air pressure p in the variable air pressure chamber (16) reaches a value of p2 and remains stable, just forming a target shape elastic guide section annular wall (5d); All the electromagnets (190) are controlled to be powered off, and then the endpoints of the upper ends of the plurality of benchmarks (21) are fitted with a curve to obtain a final fitting curve (31); the obtained fitting curve (31) is exactly the cross-sectional contour line of the elastic guide section annular wall (5d) of the target shape.

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