Adjustable fan volute, test fan and cushion thickness design method

Abstract

The application relates to a type-line-adjustable fan volute, a test fan and a cushion thickness design method, which can improve fan performance and significantly reduce design iteration time and manufacturing cost. The type-line-adjustable fan volute comprises a volute frame including a pair of end covers arranged at intervals, each end cover being provided with an air inlet and a plurality of adjusting grooves arranged around the air inlet; a volute ring wall including an elastic side wall movably arranged between the two end covers and a volute tongue fixedly arranged between the two end covers; one end of the elastic side wall is fixedly connected to the two end covers to form an air outlet together with the volute tongue; the other end of the elastic side wall sequentially passes through the plurality of adjusting grooves and is wound in the volute tongue to form a winding drum; and a plurality of adjusting pieces, each adjusting piece comprising an adjusting rod adjustably inserted into the adjusting grooves on the two end covers and a cushion fixedly connected to the adjusting rod, the cushion being located between the adjusting rod and the elastic side wall to be flexibly abutted against the elastic side wall.

Description

Technical Field

[0001] This invention relates to the field of centrifugal fan technology, and in particular to a design method for an adjustable profile fan casing, a test fan, and a buffer pad thickness. Background Technology

[0002] In the development and design of range hoods, the experimental testing of centrifugal fans plays a crucial role. This is because such testing not only ensures that the fan performance meets specific requirements but also helps optimize the design, improve energy efficiency, and reduce noise. Ultimately, through precise testing, engineers can verify and improve design solutions, thereby producing more efficient and user-friendly range hoods.

[0003] However, in the traditional centrifugal fan testing process, the design and manufacturing of the volute structure faces a significant challenge. Specifically, whenever test data reveals design deficiencies and a new design solution needs to be explored, engineers must fabricate an entirely new volute. This not only leads to long prototyping times but also significantly increases the testing cycle, thereby impacting product launch time and significantly increasing centrifugal fan development costs. Especially in today's increasingly competitive market, such delays and increased costs can have a serious negative impact on a company's market position. Summary of the Invention

[0004] Therefore, it is necessary to address the problems of long testing cycles and high development costs of volute structures. This invention provides a design method for an adjustable profile fan volute, a test fan, and a buffer pad thickness, which can improve fan performance and significantly reduce design iteration time and manufacturing costs.

[0005] In one embodiment of this application, the present invention provides a profile-adjustable fan casing, comprising:

[0006] The volute frame includes a pair of end caps arranged at intervals, each end cap having an air inlet and a plurality of adjustment slots arranged around the air inlet;

[0007] The volute annular wall includes an elastic sidewall movably disposed between the two end caps and a volute tongue fixedly disposed between the two end caps; one end of the elastic sidewall is fixedly connected to the two end caps to form an air outlet with the volute tongue; the other end of the elastic sidewall passes sequentially through a plurality of adjustment grooves and is wound into the volute tongue to form a roll; and

[0008] Multiple adjusting components, each of the adjusting components including an adjusting rod that is adjustablely inserted into the adjusting slots opposite to the two end caps and a buffer pad that is fixedly connected to the adjusting rod, the buffer pad being located between the adjusting rod and the elastic sidewall to flexibly abut against the elastic sidewall.

[0009] According to one embodiment of this application, the adjusting rod includes a screw fixedly connected to the buffer pad and a nut matching the screw; the screw passes through the two opposing adjusting grooves on the two end caps, and the nut is threadedly connected to the screw.

[0010] According to one embodiment of this application, the screw has a mounting surface facing the elastic sidewall, and the buffer pad is attached to the mounting surface of the screw.

[0011] According to one embodiment of this application, the length of the buffer pad is equal to the width of the elastic sidewall; the width of the buffer pad is equal to the diameter of the screw.

[0012] According to one embodiment of this application, a notch groove is provided on the screw at a portion corresponding to the elastic sidewall to accommodate the buffer pad, so as to provide the mounting surface through the bottom of the notch groove; the width of the mounting surface is equal to the diameter of the screw.

[0013] According to one embodiment of this application, the thickness of the cushioning pad satisfies the following relationship:

[0014] and

[0015]

[0016] Where: th is the thickness of the buffer pad; F is the base pressure; E is the elastic modulus of the buffer pad; Lh is the length of the buffer pad; L is the radius of curvature of the volute ring wall; δ max σ is the limit of acceptable deviation of the volute annular wall; K is the estimated safety factor; v S is the air pressure inside the volute of the adjustable profile fan; S is the circumference of the profile of the volute annular wall.

[0017] According to one embodiment of this application, the thickness of the cushioning pad is between 0.84 mm and 1.67 mm.

[0018] According to one embodiment of this application, the adjustable profile fan casing further includes a pair of sealing gaskets, the two sealing gaskets being respectively fixed to the inner walls of the two end caps and located between the end caps and the casing annular wall to fill the gap between the end caps and the casing annular wall.

[0019] According to another aspect of this application, an embodiment of this application further provides a test fan, comprising:

[0020] The adjustable profile fan casing described above; and

[0021] An impeller is rotatably mounted on the volute of the profile-adjustable fan.

[0022] According to another aspect of this application, an embodiment of this application further provides a method for designing the thickness of a cushioning pad, including the steps of:

[0023] By performing strain analysis on the buffer pad under both basic and working conditions, the basic deformation estimation model and the working deformation estimation model of the buffer pad are obtained.

[0024] Based on the elastic compression range of the buffer pad, the deformation estimation model of the foundation is processed to obtain the minimum thickness calculation model of the buffer pad.

[0025] Based on the acceptable limit deviation of the volute ring wall, the deformation estimation model is processed to obtain the calculation model for the maximum thickness of the buffer pad; and

[0026] Based on the basic working condition and the volute parameters under this working condition, the thickness range of the buffer pad is calculated using the minimum thickness calculation model and the maximum thickness calculation model.

[0027] 11. The buffer pad thickness design method according to claim 10, characterized in that the basic deformation estimation model is:

[0028]

[0029] Where: ε b denoted as , where is the basic deformation of the buffer pad; F is the basic pressure; th is the thickness of the buffer pad; E is the elastic modulus of the buffer pad; Lh is the length of the buffer pad; and L is the radius of curvature of the volute ring wall.

[0030] 12. The buffer pad thickness design method according to claim 10, characterized in that the working deformation estimation model is:

[0031]

[0032] Where: ε f ε represents the working deformation of the buffer pad. b The basic deformation of the buffer pad; L is the radius of curvature of the volute ring wall; K is the estimated safety factor; σ v t is the wind pressure on the elastic sidewall of the volute ring wall; S is the circumference of the profile of the volute ring wall; th is the thickness of the buffer pad; E is the elastic modulus of the buffer pad.

[0033] In summary, during testing, the adjustable fan casing of this application allows each adjusting component to be fixed at the required position on the corresponding adjusting groove according to the design requirements. Furthermore, under the influence of internal wind pressure, the elastic sidewall flexibly abuts against the buffer pad of the adjusting component, enabling flexible surface contact between the buffer pad and the elastic sidewall. This increases the contact area, reducing stress concentration and improving the smoothness of the elastic sidewall. Specifically, by designing the thickness of the buffer pad, this application not only ensures reduced stress concentration and improved smoothness of the elastic sidewall but also ensures the stability of the casing ring wall profile, avoiding any adverse impact on the accuracy of the test results.

[0034] Furthermore, if, after testing and analysis, deficiencies are found in the previous design and a new design solution needs to be attempted, the profile of the volute ring wall can be adjusted simply by adjusting the fixed position of the adjusting component on the corresponding adjusting groove according to the new design solution. This eliminates the need for engineers to fabricate a completely new volute, significantly shortening the testing cycle, reducing development costs, and avoiding impacts on product launch time. Especially in today's increasingly competitive market, the substantial reduction in testing cycle and cost will have a positive impact on the company's market position. Attached Figure Description

[0035] Figure 1 This is a perspective view of an adjustable fan casing according to an embodiment of this application;

[0036] Figure 2 An exploded view of the profile-adjustable fan casing of the above-described embodiment of this application is shown;

[0037] Figure 3 An enlarged schematic diagram of the adjusting member in the volute of the profile-adjustable fan of the above embodiment of this application is shown;

[0038] Figure 4 An exploded view of the adjusting member according to the above embodiments of this application is shown;

[0039] Figure 5 A cross-sectional schematic diagram of the profile-adjustable fan casing of the above embodiment of this application is shown;

[0040] Figure 6 It shows Figure 5 The diagram shows an enlarged view of part A in the volute of an adjustable-profile fan.

[0041] Figure 7 It shows Figure 5 The diagram shows an enlarged view of part B in the volute of the adjustable profile fan.

[0042] Figure 8A schematic diagram illustrating the strain principle of the buffer pad in the adjusting member of the above embodiment of this application under basic working conditions is shown.

[0043] Figure 9 A schematic diagram illustrating the strain principle of the buffer pad in the adjusting member of the above embodiment of this application under working conditions is shown.

[0044] Figure 10 This is a schematic diagram of a buffer pad thickness design method according to an embodiment of this application.

[0045] Explanation of main component symbols: 1. Adjustable profile fan volute; 10. Volute frame; 11. End cover; 111. Air inlet; 112. Adjustment groove; 1121. Racetrack-shaped slide groove; 1122. Slot; 20. Volute ring wall; 21. Elastic side wall; 210. Drum; 22. Volute tongue; 221. Winding chamber; 222. Guide hole; 23. Spring; 30. Adjusting component; 31. Adjusting rod; 311. Screw; 3111. Mounting surface; 3112. Notch groove; 312. Nut; 32. Buffer pad; 40. Sealing gasket; 400. Chamfered bevel.

[0046] The above description of the main component symbols, together with the accompanying drawings and specific embodiments, provides a more detailed explanation of the present invention. Detailed Implementation

[0047] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation shown in the accompanying drawings.

[0049] The positional relationships are provided only for the convenience of describing the invention and for simplifying the description, and are not intended to 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 limiting the invention.

[0050] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0051] In this invention, 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 or an electrical 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, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0052] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0053] In traditional centrifugal fan testing, whenever test data reveals design deficiencies and a new design solution needs to be attempted, engineers must fabricate a completely new volute. This not only leads to long prototyping times but also significantly increases the testing cycle, thus impacting product time-to-market and significantly increasing centrifugal fan development costs. Therefore, this application provides a method for designing an adjustable profile fan volute, a test fan, and a buffer pad thickness, which can significantly reduce design iteration time and manufacturing costs.

[0054] Specifically, see the attached document. Figures 1 to 9 As shown, one embodiment of this application provides a test fan, which may include an adjustable fan casing 1 and an impeller (not shown) rotatably disposed on the adjustable fan casing 1, for performing optimization tests on a centrifugal fan. It is understood that the impeller of this application may include, but is not limited to, a shaft, a motor driven and connected to the shaft, and a plurality of blades arranged circumferentially along the shaft; further details will not be elaborated here.

[0055] More specifically, such as Figures 1 to 6As shown, the adjustable fan casing 1 may include a casing frame 10, a casing annular wall 20, and multiple adjusting members 30. The casing frame 10 includes a pair of end caps 11 spaced apart, each end cap 11 having an air inlet 111 and multiple adjusting grooves 112 arranged around the air inlet 111. The casing annular wall 20 includes an elastic sidewall 21 movably disposed between the two end caps 11 and a volute tongue 22 fixed between the two end caps 11; one end of the elastic sidewall 21 is fixedly connected to the two end caps 11 to form an air outlet with the volute tongue 22; the other end of the elastic sidewall 21 passes sequentially through the multiple adjusting grooves 112 and is wound into the volute tongue 22 to form a roll 210. The two ends of each adjusting member 30 are respectively adjustablely inserted into the opposing adjusting grooves 112 on the two end caps 11 and are located outside the elastic sidewall 21 to adjust the profile of the casing annular wall 20. It is understood that the elastic sidewall 21 mentioned in this application may be implemented as a metal roll or a plastic roll, as long as it can undergo elastic deformation in the radial direction of the air inlet 111. This application will not elaborate further on this.

[0056] It is worth noting that during the testing process using this test fan, each adjusting component 30 can be fixed in the required position on the corresponding adjusting groove 112 according to the profile design requirements. At this time, the impeller rotates to increase the air pressure inside the volute, causing the elastic sidewall 21 to abut against all the adjusting components 30 under the action of the air pressure, ensuring that the actual profile of the volute ring wall 20 is consistent with the design profile. After testing and analysis, if it is found that the previous design has shortcomings and a new design scheme needs to be tried, it is only necessary to adjust the fixed position of the adjusting component 30 on the corresponding adjusting groove 112 according to the new design scheme to achieve the profile adjustment of the volute ring wall 20. There is no need for engineers to process a completely new volute, which helps to significantly shorten the testing cycle, reduce development costs, and avoid affecting the product launch time. Especially in today's increasingly competitive market, the significant reduction in testing cycle and cost will have a positive impact on the company's market position.

[0057] Furthermore, since the other end of the elastic sidewall 21 is rolled up within the volute tongue 22, the circumference of the volute annular wall 20 can be adjusted to meet the needs of different profile design schemes. In other words, when the profile circumference in the profile design scheme becomes shorter, the elastic sidewall 21 can be partially rolled up within the volute tongue 22 to shorten the circumference of the volute annular wall 20; when the profile circumference in the profile design scheme becomes longer, the elastic sidewall 21 can be partially pulled out from the volute tongue 22 to lengthen the circumference of the volute annular wall 20, greatly increasing the flexibility of profile design adjustment.

[0058] According to the above embodiments of this application, as Figure 2 , Figure 5 as well as Figure 6 As shown, the volute annular wall 20 may further include a spring 23 disposed between the drum 210 and the volute tongue 22, for applying a winding torque to the drum 210, so that the other end of the elastic sidewall 21 can automatically wind into the volute tongue 22 under the action of the spring 23, so as to ensure that the elastic sidewall 21 is always in an automatically tensioned state. In this way, when the fixed position of the adjusting member 30 is adjusted to adjust the annular wall profile, if the annular wall circumference increases, the drum 210 will partially extend out of the volute tongue 22 and abut against the adjusting member 30 under the action of its own elasticity and the air pressure inside the volute; if the annular wall circumference decreases, the excessively long part of the elastic sidewall 21 will automatically wind back into the volute tongue 22 under the action of the spring 23, and the volute annular wall 20 can still abut against the adjusting member 30 under the action of its own elasticity and the air pressure inside the volute, thereby realizing the controllable adjustment of the annular wall profile.

[0059] Furthermore, since the spring 23 exerts an inward contraction force (referred to as contraction force) on the elastic sidewall 21, while the airflow generated by the impeller rotation exerts an outward expansion force (referred to as expansion force) on the elastic sidewall 21, when the adjusting member 30 is fixed at a certain position in the adjusting groove 112, the expansion force on the elastic sidewall 21 needs to be greater than the contraction force on the elastic sidewall 21 in order for the elastic sidewall 21 to abut against the adjusting member 30 to ensure that the volute profile is in a stable state. However, the contraction force on the elastic sidewall 21 is related to the circumference of the ring wall, and for some profile designs with a large ring wall circumference, the larger the ring wall circumference, the greater the contraction force on the elastic sidewall 21, which can easily lead to instability in the profile structure.

[0060] To solve this problem, such as Figure 2 and Figure 6 As shown, the volute tongue 22 of this application may have a take-up cavity 221 for accommodating the spool 210 and a guide hole 222 communicating with the take-up cavity 221. The other end of the elastic sidewall 21 passes through the guide hole 222 to be wound into the take-up cavity 221 of the volute tongue 22, so that it can extend or retract into the take-up cavity 221 under the guidance of the guide hole 222. In this way, the elastic sidewall 21 will generate friction with the hole wall of the guide hole 222 during the process of passing through the guide hole 222, thus having a certain self-locking ability, thereby limiting the influence of the shrinkage force on the profile structure and helping to improve the stability of the profile structure.

[0061] According to the above embodiments of this application, as Figure 5As shown, multiple regulating grooves 112 can be arranged along a basic volute profile to reduce unnecessary slotting and decrease the slotted area on the end cap 11, thereby helping to reduce gas leakage. It is understood that the basic volute profile mentioned in this application can be, but is not limited to, implemented as a logarithmic spiral or an Archimedean spiral, etc., which will not be elaborated further in this application.

[0062] Optionally, such as Figure 7 As shown, the adjustment groove 112 has a racetrack-shaped slide groove 1121 that matches the adjustment member 30, and multiple slots 1122 that communicate with the racetrack-shaped slide groove 1121 and engage with the adjustment member 30. Thus, the adjustment member 30 can slide along the racetrack-shaped slide groove 1121 to engage with different slots 1122, achieving the engagement and fixation of the adjustment member 30 with the end cover 11, thereby completing the adjustment of the volute profile. It can be understood that, theoretically, with N adjustment grooves 112, each with X slots 1122, the profile-adjustable fan volute 1 of this application can be tested with N... X The adjustable volute profile design allows for testing of a thousand different volute profile designs. For example, if there are ten adjustment slots 112, each with three slots 1122, then the adjustable volute profile design of this application can test a thousand different volute profile designs without waiting for a new volute to be manufactured, thus significantly improving testing efficiency.

[0063] Preferably, such as Figure 5 As shown, the racetrack-shaped chute 1121 extends radially along the air inlet 111 in order to minimize the length of the racetrack-shaped chute 1121 while meeting the requirements for volute profile adjustment, thus helping to reduce gas leakage.

[0064] It is worth noting that, because the other end of the elastic sidewall 21 needs to be rolled up within the volute tongue 22, in order to ensure the flexibility of the overall assembly and the elastic sidewall 21, the actual width of the elastic sidewall 21 usually needs to be smaller than the distance between the two end caps 11. This will cause a large amount of airflow to leak from the gap between the elastic sidewall 21 and the end cap 11, easily causing the test fan to malfunction. To solve this problem, such as... Figure 1 and Figure 2 As shown, the profile-adjustable fan volute 1 of this application may further include a pair of sealing gaskets 40. The two sealing gaskets 40 are respectively fixed to the inner walls of the two end caps 11 and located between the end caps 11 and the volute annular wall 20 to fill the gap between the end caps 11 and the volute annular wall 20, thereby ensuring the sealing effect of the profile-adjustable fan volute 1.

[0065] Optionally, such as Figure 2 and Figure 6As shown, the inner edge of the sealing gasket 40 is inclined toward the air inlet 111 to form a chamfered surface 400, so as to reduce the disturbance effect of the sealing gasket 40 on the airflow inside the volute and make the experimental results more reliable.

[0066] According to the above embodiments of this application, as Figures 3 to 7 As shown, the adjusting member 30 may include an adjusting rod 31 that is adjustablely inserted into the adjusting groove 112 opposite to the two end caps 11, so as to adjust the fixed position of the adjusting rod 31 along the adjusting groove 112 to adjust the annular wall profile.

[0067] It is worth noting that if the adjusting rod 31 is directly and rigidly in contact with the elastic sidewall 21, since the elastic sidewall 21 is curved, the elastic sidewall 21 and the adjusting rod 31 will be in line contact, that is, the contact area between the two is extremely small, which will cause stress concentration. This will easily cause the part of the elastic sidewall 21 that contacts the adjusting rod 31 to produce concave deformation, while other parts will produce convex bending deformation, resulting in a reduction in the smoothness of the volute profile, which will have an adverse effect on the test results.

[0068] To solve this problem, such as Figures 3 to 9 As shown, the adjusting member 30 of this application may further include a buffer pad 32 fixedly connected to the adjusting rod 31. The buffer pad 32 is located between the adjusting rod 31 and the elastic sidewall 21, flexibly abutting against the elastic sidewall 21, so that the buffer pad 32 and the elastic sidewall 21 have flexible surface contact, thereby increasing the contact area between the two, which helps to reduce stress concentration and improve the smoothness of the elastic sidewall 21. In other words, the adjusting member 30 of this application can increase the contact area with the elastic sidewall 21 through the flexible deformation of the buffer pad 32, which facilitates the reduction of stress concentration and helps to improve the smoothness of the ring wall profile. It is understood that the buffer pad 32 mentioned in this application may be, but is not limited to, made of flexible materials such as silicone or rubber.

[0069] Optionally, such as Figure 4 As shown, the adjusting rod 31 may include a screw 311 fixedly connected to the buffer pad 32 and a nut 312 matching the screw 311. The screw 311 passes through the opposing adjusting grooves 112 on the two end caps 11, and the nut 312 is threadedly connected to the screw 311 to achieve the positioning and fixing of the adjusting member 30.

[0070] It is worth noting that since the cap of the screw 311 and the nut 312 can partially or completely cover the adjustment groove 112, the nut 312 is threadedly connected to the screw 311 to provide positioning and fixation, while also partially or completely blocking the adjustment groove 112, which helps to further reduce gas leakage and improve the performance of the fan.

[0071] Optionally, such as Figure 3 and Figure 4 As shown, the screw 311 has a mounting surface 3111 facing the elastic sidewall 21. The buffer pad 32 is attached to the mounting surface 3111 of the screw 311, so that the buffer pad 32 is located on the side of the screw 311 adjacent to the elastic sidewall 21, which facilitates better flexible fit to the elastic sidewall 21. It is understood that the buffer pad 32 of this application can be, but is not limited to, bonded to the mounting surface 3111.

[0072] Optionally, the length Lh of the cushioning pad 32 is equal to the width of the elastic sidewall 21.

[0073] Optionally, the width of the buffer pad 32 is equal to the diameter of the screw 311.

[0074] Optionally, such as Figure 3 and Figure 4 As shown, a notch 3112 is provided on the screw 311 at the part corresponding to the elastic sidewall 21 to accommodate the buffer pad 32, so that the mounting surface 3111 is provided through the bottom of the notch 3112, which helps to improve the compactness of the overall structure.

[0075] Optionally, the width of the mounting surface 3111 is equal to the diameter of the screw 311, that is, the central axis of the screw 311 lies in the plane where the mounting surface 3111 is located, so that the mounting surface 3111 can match the cross-section of the buffer pad 32.

[0076] It is worth noting that although the buffer pad 32 can increase the contact area between the adjusting member 30 and the elastic sidewall 21, thus reducing stress concentration, the elastic compression of the buffer pad 32 will vary under different test conditions. This will cause slight disturbances in the volute profile under different conditions, affecting the stability of the test results. Specifically, under lower operating conditions, the actual profile of the volute annular wall 20 will shift relatively inward; while under higher operating conditions, the actual profile of the volute annular wall 20 will shift relatively outward.

[0077] In other words, if the buffer pad 32 is too thick, the profile offset of the volute ring wall 20 will increase, leading to instability in the profile of the volute ring wall 20 and adversely affecting the accuracy of the test results. Conversely, if the buffer pad 32 is too thin, its effect in reducing stress concentration will also decrease. Therefore, to solve this problem, this application requires a buffer pad 32 of appropriate thickness to reduce stress concentration while ensuring the profile stability of the volute ring wall 20.

[0078] Specifically, in order to determine the thickness range of the cushioning pad 32, this application first... Figure 8Strain analysis was performed on the buffer pad 32 under the basic working conditions shown to obtain the minimum thickness of the buffer pad 32 (i.e., the left end point of the thickness range), and then... Figure 9 Strain analysis was performed on the buffer pad 32 under the operating conditions shown to obtain the maximum thickness of the buffer pad 32 (i.e., the right end of the thickness range). It is understood that the basic operating conditions mentioned in this application refer to the operating conditions in which no wind pressure is generated in the volute before the impeller rotates; the operating conditions mentioned in this application refer to the operating conditions in which the maximum wind pressure is generated in the volute after the impeller rotates.

[0079] It is worth noting that, for example Figure 8 As shown, under basic operating conditions, in order to ensure that the elastic sidewall 21 does not detach from the adjusting member 30, a basic outward tensioning pressure F is usually applied to the elastic sidewall 21 when adjusting the length of the ring wall, so that the elastic sidewall 21 fits against the buffer pad 32; and under the action of the basic pressure F, the buffer pad 32 will deform inward, so that the buffer pad 32 has a basic deformation amount ε. b At this time, the contact area between the buffer pad 32 and the elastic sidewall 21 is A = ΔS*Lh, where ΔS is the arc length of the contact segment between the elastic sidewall 21 and the buffer pad 32; Lh is the length of the buffer pad 32, which is usually designed based on the width of the elastic sidewall 21, generally between 100mm and 400mm, and is considered known in this application.

[0080] Furthermore, due to the basic deformation ε of the buffer pad 32 b Since the radius of curvature L of the volute ring wall 20 is very small, the arc length ΔS of the basic contact section between the elastic sidewall 21 and the buffer pad 32 can satisfy the following relationship (1):

[0081]

[0082] In the formula: L is the radius of curvature of the annular wall 20 of the volute; ε b This represents the basic deformation of the buffer pad 32.

[0083] And due to the basic stress σ on the buffer pad 32 b The relationship between the basic pressure F and the equation is as follows: Furthermore, the buffer pad 32 is subjected to the basic stress σ b With the basic deformation ε b Satisfying the relation Therefore, combining the above relation (1), we can obtain:

[0084]

[0085] The basic deformation ε of the buffer pad 32 can be obtained by sorting. b The following relation (2) must be satisfied:

[0086]

[0087] However, because the radius of curvature L is much larger than the basic deformation ε b Therefore, the above relation (2) can be simplified to:

[0088]

[0089] Further refinement yields the basic deformation estimation model:

[0090]

[0091] Where: ε b Here, F represents the basic deformation of the buffer pad 32; th represents the basic pressure; th represents the thickness of the buffer pad 32; E represents the elastic modulus of the buffer pad 32; Lh represents the length of the buffer pad 32; and L represents the radius of curvature of the volute annular wall 20. It is understood that the basic pressure F mentioned in this application is usually applied manually and generally does not exceed 100N. For safety reasons, the basic pressure F in this application is preferably estimated to be between 200N and 300N. The elastic modulus E mentioned in this application generally depends on the type of material of the buffer pad 32, which is considered known in this application.

[0092] It is worth noting that, due to the curvature radius L mentioned in this application being related to the basic deformation ε b A negative correlation is observed, resulting in the minimum value of the radius of curvature L and the minimum value of the foundation deformation ε. b There is a maximum value; therefore, to simplify the calculation, this application can select the distance L between the location of the elastic sidewall 21 near the adjustment groove 112 of the volute tongue 22 and the center of the volute (i.e., the center of the air inlet 111 on the end cover 11). min The radius of curvature L of the volute annular wall 20 is considered known in this application.

[0093] Generally speaking, in order to ensure that the buffer pad 32 is within the elastic compression range, it should meet the following requirements: Considering the deformation under the reserved working load, this application raises the requirements and limits the thickness of the buffer pad 32 to satisfy the following elastic compression relationship (3).

[0094]

[0095] Substituting the above basic deformation estimation model into the above relationship (3), we can obtain:

[0096]

[0097] The minimum thickness calculation model for the buffer pad 32 can be obtained by refining the formula:

[0098]

[0099] Where: th is the thickness of the buffer pad 32; F is the basic pressure; E is the elastic modulus of the buffer pad 32; Lh is the length of the buffer pad 32; and L is the radius of curvature of the volute ring wall 20.

[0100] Optionally, when the foundation pressure (i.e., foundation load force) F = 200 N; the length of the buffer pad 32 Lh = 0.2 m; the radius of curvature of the volute ring wall 20 L = 0.15 m; and the elastic modulus of the buffer pad 32 E = 1 MPa, based on the minimum thickness model, the thickness th of the buffer pad 32 should satisfy the following relationship:

[0101]

[0102] In other words, the thickness th of the buffer pad 32 is preferably greater than or equal to 0.84 mm; that is, the minimum thickness of the buffer pad 32 is 0.84 mm.

[0103] Similarly, such as Figure 9 As shown, under operating conditions, the elastic sidewall 21 is subjected to wind pressure σ applied by the airflow. v Since the maximum static pressure of centrifugal fans on the market is usually no more than 1300 Pa, the wind pressure σ in this application is... v The value is preferably taken between 1500 Pa and 2000 Pa for design estimation.

[0104] It is worth noting that, due to this wind pressure σ v The stress will be applied to the entire surface of the volute annular wall 20, while the buffer pad 32 only contacts a portion of the elastic sidewall 21. Therefore, the working stress σ of the buffer pad 32 is... f The following relationship should be satisfied: σ v *S≈σ f *n*Δs f .

[0105] Considering the estimated safety factor K, the working stress σ of the buffer pad 32 in this application is... f The following relation (4) should be satisfied:

[0106]

[0107] Where: σ v The wind pressure experienced by the elastic sidewall 21; K is the estimated safety factor; S is the profile circumference of the volute annular wall 20; σ f The working stress of the buffer pad 32 is n; the number of the adjusting components 30 is n; Δs fThis refers to the arc length of the working contact section between the elastic sidewall 21 and the buffer pad 32. It is understood that the estimated safety factor K mentioned in this application is generally between 1.0 and 1.2; the profile circumference S mentioned in this application generally refers to the length of the elastic sidewall 21 extending from the volute tongue 22, which is considered known in this application; the number n of the adjusting members 30 is generally between ten and thirty.

[0108] Furthermore, due to the working deformation ε of the buffer pad 32 f The radius of curvature L of the volute annular wall 20 is very small, therefore the arc length Δs of the working contact section between the elastic sidewall 21 and the buffer pad 32 is small. f The following relation (5) can be satisfied:

[0109]

[0110] In the formula: L is the radius of curvature of the annular wall 20 of the volute; ε b ε represents the basic deformation of the buffer pad 32. f This represents the working deformation of the buffer pad 32.

[0111] Similarly, the working stress σ experienced by the buffer pad 32 f With the working deformation ε f Satisfying the relation By further combining the above relations (4) and (5), we can obtain:

[0112]

[0113] The working deformation ε of the buffer pad 32 can be obtained from the analysis. f The following relation (6) must be satisfied:

[0114]

[0115] However, because the radius of curvature L is much larger than the basic deformation ε b And it is much larger than the working deformation ε f Therefore, the above relation (6) can be simplified to:

[0116]

[0117] Further refinement yields the working deformation estimation model:

[0118]

[0119] Where: ε f ε represents the working deformation of the buffer pad 32. b The basic deformation of the buffer pad 32; L is the radius of curvature of the volute annular wall 20; K is the estimated safety factor; σv S is the wind pressure on the elastic sidewall 21; S is the circumference of the profile of the volute annular wall 20; th is the thickness of the buffer pad 32; and E is the elastic modulus of the buffer pad 32.

[0120] It is worth noting that, since the manufacturing process of the volute itself has a certain acceptable tolerance range, this application considers elastic deformation caused by the buffer pad 32 to be less than 30% of the tolerance range as acceptable elastic deformation. Taking GB / T1804, which does not specify dimensional tolerances, as an example, it gives the limit deviation values ​​for linear dimensions; while volute machining usually adopts at least the medium or higher tolerance grades shown in the table below.

[0121]

[0122] As shown in the table above, the limit size range is smaller in areas with smaller size segments. Moving the position of the adjusting member 30 in this application actually adjusts the distance from a certain point on the elastic sidewall 21 to the center of the volute (i.e., the center of the air inlet 111 on the end cover 11). Clearly, the distance between the part of the elastic sidewall 21 near the volute tongue 22 and the center of the volute is smaller. In this application, after the end cover 11 and the air inlet 111 are determined based on design and testing requirements, the distance L between the part of the elastic sidewall 21 near the adjusting groove 112 of the volute tongue 22 and the center of the air inlet 111 on the end cover 11 is... min This can be determined; then, based on the table above, the limit of acceptable deviation δ of the volute annular wall 20 can be determined. max Therefore, the working deformation ε of the buffer pad 32 can be determined. f The following relation (7) should be satisfied:

[0123] ε f ≤0.3*δ max (7);

[0124] Substituting the above working deformation estimation model into the above relation (7), we can obtain:

[0125]

[0126] Since it is easy to know from relation (3) that (0.3*δ) max ) 2 (0.3*δ max +0.1*th)≥(0.3*δ max ) 2 (0.3*δ max +ε b Therefore, the maximum thickness calculation model for the buffer pad 32 can be implemented as follows:

[0127]

[0128] Where: th is the thickness of the buffer pad 32; δ max The limit of acceptable deviation for the volute annular wall 20; L is the radius of curvature of the volute annular wall 20; K is the estimated safety factor; σ v S is the air pressure inside the volute 1 of the adjustable fan; S is the circumference of the profile of the volute annular wall 20; E is the elastic modulus of the buffer pad 32.

[0129] It is worth noting that the maximum thickness of the buffer pad 32 can be obtained by solving the inequality of this maximum thickness calculation model. Optionally, when the radius of curvature L of the volute annular wall 20 is L... min When the diameter is 150 mm, the limit acceptable deviation δ of the volute annular wall 20 is... max =0.5mm*2=0.001m; the estimated safety factor K is taken as 1; the air pressure σ inside the volute 1 of this type of adjustable fan. v Taking 1500 Pa; the circumference S of the profile of the volute annular wall 20 is taken as 1 m; the elastic modulus E of the buffer pad 32 is taken as 1 MPa = 100000 Pa; then the maximum thickness calculation model can be converted to 1.5 * 10 7 *th 2 -9000th-27≤0; Solving, we get: -1.07mm≤th≤1.67mm.

[0130] Considering that the thickness of the buffer pad 32 cannot be negative, the thickness th of the buffer pad 32 in this application is less than or equal to 1.67 mm; that is, the maximum thickness of the buffer pad 32 is 1.67 mm.

[0131] In summary, the thickness of the buffer pad 32 is preferably between 0.84 mm and 1.67 mm.

[0132] It is worth mentioning that, according to another aspect of this application, such as Figure 10 As shown, one embodiment of this application further provides a method for designing the thickness of a cushioning pad, which includes the following steps:

[0133] S100: Under basic working conditions and working conditions, strain analysis is performed on the buffer pad to obtain the basic deformation estimation model and the working deformation estimation model of the buffer pad.

[0134] S200: Based on the elastic compression range of the buffer pad, the deformation estimation model of the foundation is processed to obtain the minimum thickness calculation model of the buffer pad.

[0135] S300: Based on the acceptable limit deviation of the volute annular wall, the deformation estimation model is processed to obtain the calculation model for the maximum thickness of the buffer pad; and

[0136] S400: Based on the basic working condition and the volute parameters under the working condition, the thickness range of the buffer pad is calculated using the minimum thickness calculation model and the maximum thickness calculation model.

[0137] It is worth noting that the basic deformation estimation model mentioned in this application can be implemented as follows:

[0138]

[0139] Where: ε b denoted as , where is the basic deformation of the buffer pad; F is the basic pressure; th is the thickness of the buffer pad; E is the elastic modulus of the buffer pad; Lh is the length of the buffer pad; and L is the radius of curvature of the volute ring wall.

[0140] The deformation estimation model mentioned in this application can be implemented as follows:

[0141]

[0142] Where: ε f ε represents the working deformation of the buffer pad. b The basic deformation of the buffer pad; L is the radius of curvature of the volute ring wall; K is the estimated safety factor; σ v S is the wind pressure on the elastic sidewall; S is the circumference of the profile of the volute ring wall; th is the thickness of the buffer pad; and E is the elastic modulus of the buffer pad.

[0143] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0144] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A fan casing with adjustable profile, characterized in that, include: The volute frame includes a pair of end caps arranged at intervals, each end cap having an air inlet and a plurality of adjustment slots arranged around the air inlet; The volute annular wall includes an elastic sidewall movably disposed between the two end caps and a volute tongue fixedly disposed between the two end caps; one end of the elastic sidewall is fixedly connected to the two end caps to form an air outlet with the volute tongue; the other end of the elastic sidewall passes through a plurality of adjustment grooves in sequence and is wound into the volute tongue to form a roll. as well as Multiple adjusting components, each of the adjusting components including an adjusting rod that is adjustablely inserted into the adjusting slots opposite to the two end caps and a buffer pad that is fixedly connected to the adjusting rod, the buffer pad being located between the adjusting rod and the elastic sidewall to flexibly abut against the elastic sidewall.

2. The adjustable profile fan casing according to claim 1, characterized in that, The adjusting rod includes a screw fixedly connected to the buffer pad and a nut matching the screw; the screw passes through the two opposing adjusting grooves on the two end caps, and the nut is threadedly connected to the screw.

3. The adjustable profile fan casing according to claim 2, characterized in that, The screw has a mounting surface facing the elastic sidewall, and the buffer pad is attached to the mounting surface of the screw.

4. The adjustable profile fan casing according to claim 3, characterized in that, The length of the buffer pad is equal to the width of the elastic sidewall; the width of the buffer pad is equal to the diameter of the screw.

5. The adjustable profile fan casing according to claim 4, characterized in that, A notch or groove is provided on the screw at a location corresponding to the elastic sidewall to accommodate the buffer pad, so as to provide the mounting surface through the bottom of the notch or groove; the width of the mounting surface is equal to the diameter of the screw.

6. The adjustable profile fan casing according to any one of claims 1 to 5, characterized in that, The thickness of the cushioning pad satisfies the following relationship: ;and ； Where: th is the thickness of the buffer pad; F is the base pressure; E is the elastic modulus of the buffer pad; Lh is the length of the buffer pad; and L is the radius of curvature of the volute ring wall. K represents the limit of acceptable deviation of the volute annular wall; K is the estimated safety factor. S is the air pressure inside the volute of the adjustable profile fan; S is the circumference of the profile of the volute annular wall.

7. The adjustable profile fan casing according to any one of claims 1 to 5, characterized in that, The thickness of the cushioning pad is between 0.84 mm and 1.67 mm.

8. The adjustable profile fan casing according to any one of claims 1 to 5, characterized in that, It also includes a pair of sealing gaskets, which are respectively fixed to the inner walls of the two end caps and located between the end caps and the volute annular wall to fill the gap between the end caps and the volute annular wall.

9. A test fan, characterized in that, include: Adjustable fan casing as described in any one of claims 1 to 8; and An impeller is rotatably mounted on the volute of the profile-adjustable fan.

10. A method for designing the thickness of a cushioning pad, characterized in that, For a profile-adjustable fan casing as described in any one of claims 1 to 8, the steps include: By performing strain analysis on the buffer pad under both basic and working conditions, the basic deformation estimation model and the working deformation estimation model of the buffer pad are obtained. Based on the elastic compression range of the buffer pad, the deformation estimation model of the foundation is processed to obtain the minimum thickness calculation model of the buffer pad. Based on the acceptable limit deviation of the volute ring wall, the deformation estimation model is processed to obtain the calculation model for the maximum thickness of the buffer pad; and Based on the basic working condition and the volute parameters under this working condition, the thickness range of the buffer pad is calculated using the minimum thickness calculation model and the maximum thickness calculation model.

11. The method for designing the thickness of the buffer pad according to claim 10, characterized in that, The basic deformation estimation model is as follows: ； in: denoted as , where is the basic deformation of the buffer pad; F is the basic pressure; th is the thickness of the buffer pad; E is the elastic modulus of the buffer pad; Lh is the length of the buffer pad; and L is the radius of curvature of the volute ring wall.

12. The method for designing the thickness of the buffer pad according to claim 10, characterized in that, The deformation estimation model for this work is as follows: ； in: This represents the working deformation of the buffer pad; L is the basic deformation of the buffer pad; L is the radius of curvature of the volute ring wall; K is the estimated safety factor. t is the wind pressure on the elastic sidewall of the volute ring wall; S is the circumference of the profile of the volute ring wall; th is the thickness of the buffer pad; E is the elastic modulus of the buffer pad.

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