High-efficiency modular fan and method for manufacturing the same

Abstract

The modular axial fan (20) comprises a plurality of blades (22), each of which includes a plurality of blade mounting holes (22-2F) arranged in a circumferentially asymmetric array (FA), a forward spider and a rear spider having the same structural configuration for each of the legs of a plurality of legs extending from a center hub (24H) and a plurality of leg mounting holes (24L-1F) arranged in an array (SA), and a mechanical fixture (28) for fixing the plurality of blades to the corresponding legs. The mechanical fixture (28) is fixed in each of the plurality of blade mounting holes and a subset (SA1) of the plurality of leg mounting holes, and each leg subset (SA1) of the plurality of leg mounting holes is aligned with the plurality of blade mounting holes of the corresponding blade array (FA). At least two leg mounting holes (24L-1F' and 24L-1F'') of each leg are circumferentially offset from the subset (SA1) and are not used by the mechanical fixture and are shielded by the blades.

Description

【Technical Field】 【0001】 The present invention relates to fans, and more particularly to axial flow cooling fans having a modular design, their component blades and hub parts, and their manufacturing and use methods. 【Background Art】 【0002】 Large axial flow fans are used to meet various cooling requirements. For example, they are used for cooling generators and large mining trucks. These fan diameters usually range from 60 inches to 100 inches (152.4 cm to 254 cm). In many applications, due to the duty cycle of the device, durable and long-lasting components are required. However, the same device may be used very infrequently in other applications, allowing for many design choices regarding materials, design, and durability targets. A specific example is the comparison between a standby generator and a main generator. A standby generator is only used for a short period of time when necessary. The main power source generally needs to operate almost constantly. Therefore, the operating hours of the main generator are quickly accumulated. Due to such differences in usage methods, it is not economically efficient to use the same components in both applications. In the case of cooling fans, this expands the design and material options. 【0003】 There is a need to provide an axial flow fan that enables a highly efficient design that allows for a variety of material selections and application flexibility. Design flexibility is attractive in that it allows for various combinations to adjust fan performance to efficiently meet the air volume requirements in a given application. 【0004】 In many cases in the prior art, the fan is formed to a given diameter and reduced to a smaller diameter to fit into a restricted space. Such reduction decreases the blade length. However, it can also affect the shape of the blade, especially where the blade shape changes along its length. 【0005】 Conventional HTEC® fans, available from Horton Incorporated (Rosesville, Minnesota, USA) and / or disclosed in PCT International Publication 2015 / 171446, feature blades made of thermosetting composite material mounted to a pair of steel center discs via fasteners. To meet the robustness requirements of high-duty cycle applications such as main generators and heavy-duty mining trucks, HTEC® fans are designed with two center discs positioned on each side of the fan blades, enabling high strength and rigidity throughout the entire fan assembly. HTEC® fan blades are mounted to the center discs by a two-piece riveting system (using a two-piece fastener including pins and collars), such as those sold under the brand name huckbolt®, although other types of mechanical fasteners are also available for these fan types. These fans offer several advantages, including variable blade count in fan designs where only a selected number of blades are installed. Since the fan's center disc can be manufactured in different diameters, fans of various sizes can be produced without adjusting the blade length. This is crucial because the shape of the HTEC® fan blades is extremely important for fan performance. 【0006】 Other known fan designs, available from Horton Incorporated as large metal fans, sandwich individual metal blades between steel "spider" plates. Instead of a fully circular or annular hub plate, the spider features "legs" or "arms" extending radially from a center hub. The blades are riveted between sets of two or four spiders at the ends of the legs. Single spider configurations are also available. The spider legs not only provide a mounting method but also allow for adjustment of the blade pitch by twisting them at a specific angle. This adjustment provides further options for fine-tuning the fan performance for a given application. Spiders with legs can be designed and manufactured with different blade counts, diameters, and blade pitches, and different configurations of spiders can be used in different applications to provide the desired fan configuration. 【0007】 Further known fan designs are available from Horton Incorporated as the WindMaster® composite nylon fan, featuring plastic fan blades with a single metal spider attached to one side of each fan blade. By replacing different spiders, it is possible to provide the desired number of blades, diameter, and blade pitch. [Overview of the project] [Problems that the invention aims to solve] 【0008】 There is a need for a large axial flow fan that has the basic concept of modular blades that can be manufactured using injection-molded materials suitable for cooling applications with lower cost requirements, has improved blade mounting components, and maintains a fan blade shape that allows for relatively high-efficiency operation while maintaining the modularity of the fan diameter. [Means for solving the problem] 【0009】 In one embodiment, a modular axial fan comprises a plurality of blades, each of which includes a base having a working section and a mounting pad, with each mounting pad having a plurality of blade fixing holes arranged in an array (FA); a spider assembly including a front spider and a rear spider, each of which has a center hub and a plurality of legs extending from the center hub, and each of which has a plurality of legs having a plurality of leg fixing holes arranged in an array (SA); and a plurality of mechanical fasteners, each of which fastens each of the plurality of blades to a corresponding leg of the respective legs of the front spider and the rear spider, such that one of the plurality of mechanical fasteners fastens to each of the plurality of blades to a corresponding leg of the respective legs of the front spider and the rear spider. Here, the front spider and the rear spider have the same structural configuration. Each array (FA) of the plurality of blade fixing holes of each of the plurality of blades is asymmetrical in the circumferential direction. Multiple mechanical fasteners are fixed to a subset (SA1) of leg fixing holes in an array (SA) at each leg of the forward and rear spider, the subset (SA1) of leg fixing holes in each array (SA) of the leg is aligned with an array (FA) of blade fixing holes in a corresponding blade of the multiple blades, and at least two of the multiple leg fixing holes in each leg of the forward and rear spider are circumferentially offset from the subset (SA1) of leg fixing holes and are blocked by the base of a corresponding blade of the multiple blades so as not to be used by any of the multiple mechanical fasteners. 【0010】 In other embodiments, the modular fan includes a plurality of blades, each of which includes a base having a work portion and a mounting pad that is substantially flat, and each mounting pad having a plurality of blade fixing holes arranged in an array (FA) defined by a parallelogram outer shape of either a rhomboid or rhomboid shape; a spider assembly having a front spider and a rear spider having the same structural configuration, comprising a center hub and a plurality of legs extending from the center hub, each of the plurality of legs having a plurality of leg fixing holes arranged in an array (SA), each of the plurality of legs having a flat mounting portion and a twisted connecting portion, and the array (SA) having leg fixing holes constituting a subset (SA1) of the plurality of leg fixing holes and at least one additional fixing hole on the circumferentially opposite side of the subset (SA1); and a plurality of mechanical fasteners for fixing each of the plurality of blades to a corresponding leg of each of the legs of the front spider and the rear spider. Here, one of the multiple mechanical fasteners passes through each of the multiple blade fastening holes in each array (FA) of the multiple blades and also through each fastening hole in the subset (SA1), and at least one additional fastening hole on the opposite side of the subset (SA1) in the circumferential direction is blocked by the base of the corresponding blade of the multiple blades and is not used by any of the multiple mechanical fasteners, and the first of the at least one additional fastening hole on one side of the subset (SA1) is radially offset from the second of the at least one additional fastening hole on the other side of the subset (SA1). 【0011】 In a further embodiment, a method for manufacturing an axial flow fan includes the steps of (a) arranging a front spider adjacent to a rear spider so that they are inverted front to back, wherein the front spider and the rear spider have the same structural configuration for each leg, which is provided with a plurality of radially extending legs and a plurality of leg fixing holes arranged in an array (SA), and the array (SA) includes leg fixing holes that constitute a subset (SA1) of the plurality of leg fixing holes and at least one additional fixing hole located laterally in the circumferential direction of each subset (SA1), (b) A step of positioning a blade between a first leg of a plurality of legs of a forward spider and a first leg of a plurality of legs of a rear spider, wherein the blade is provided with a plurality of blade fixing holes located in an array (FA) via mounting pads, the blade is positioned such that a subset (SA1) of the plurality of leg fixing holes aligns with the plurality of blade fixing holes of the array (FA), and at least one additional fixing hole on each of the sides of the subset (SA1) is located outside the array (FA) and is shielded by the blade material, and (c) a step of positioning the blade on the first legs of both the forward spider and the rear spider, with one of a plurality of mechanical fasteners passing through each of the plurality of blade fixing holes of the array (FA). (d) a step of securing with a plurality of mechanical fasteners, wherein each of the plurality of mechanical fasteners passing through one of the plurality of blade fastening holes of the array (FA) also passes through one of the plurality of leg fastening holes constituting a subset (SA1) in the first leg of each of the forward spider and rear spider, and each of the at least one additional fastening hole on each side of the subset (SA1) is not used by the plurality of mechanical fasteners passing through one of the plurality of blade fastening holes of the array (FA); and (d) repeating steps (b) and (c) for an additional blade until one of the additional blades is secured to each of the remaining legs of the forward spider and rear spider. 【0012】 This summary is illustrative and not limiting. Other aspects of the present invention can be understood by referring to the entire disclosure, including the text, claims, and accompanying drawings. [Brief explanation of the drawing] 【0013】 [Figure 1] Figure 1 is a front elevation view of a modular fan according to one embodiment of the present invention. [Figure 2] Figure 2 is a cross-sectional view of a portion of a modular fan cut along line segment 2-2 in Figure 1. [Figure 3A] Figure 3A is a rear elevation view showing the modular fan blades separated. [Figure 3B] Figure 3B is a perspective view of the bottom of the blade. [Figure 4A] Figure 4A is a front perspective view showing the spider of a modular fan separated. [Figure 4A] Figure 4B is a plan view of the bottom of the blade. [Figure 5A] Figure 5A is a front elevation view of a portion of a modular fan. [Figure 5B] Figure 5B is a rear elevation view of a portion of a modular fan. 【0014】 The aforementioned figures illustrate one or more embodiments of the present invention, but other embodiments are also conceivable as mentioned in the description. In any case, this disclosure is not limiting and is presented representatively to the present invention. Those skilled in the art should understand that various other modifications and embodiments can be devised within the scope of the principles and ideas of the present invention. The drawings are not necessarily drawn to scale. Examples of applications and embodiments of the present invention may include features, steps, and / or components not specifically shown in the drawings. [Modes for carrying out the invention] 【0015】 Generally, embodiments disclosed in the present invention provide relatively high-efficiency axial fans having a modular configuration suitable for large-scale cooling applications. In some embodiments, the blades of the modular fan can be manufactured from injection-molded polymers or composite materials suitable for less cost-sensitive cooling applications. In some embodiments of the modular fan, blade mounting components with improved modularity are available. Furthermore, the modular fan can offer modular adjustment of fan diameter, number of blades, and blade pitch (without requiring, for example, a reduction in module length) while maintaining a fan blade shape that enables relatively high-efficiency operation. Methods for manufacturing and using such fans are also provided. 【0016】 This application asserts the benefits of U.S. Provisional Patent Application No. 63 / 506,269, filed on 5 June 2023, the contents of which are incorporated herein by reference. 【0017】 Depending on the application, cooling fans may require low load or infrequent duty cycles, while others demand extremely durable components with long service lives. For certain fan applications, the use of different materials and manufacturing methods in the fan design may be desirable, which is facilitated by a modular fan structure. Such desirable flexibility can be achieved by mounting the fan according to the present invention modularly to a spider hub using molded blades (e.g., a set of molded blades having a single, identical configuration). This modularity allows for adjustment of the number of blades, spider diameter, and blade pitch to suit the specific application design, while using, minimally modifying, and / or reusing a number of common modular initial components to customize the resulting fan. In embodiments of the present invention, relatively high-efficiency fan blades are available, and the overall fan diameter can be adjusted without reducing the fan blade length. 【0018】 An embodiment of the modular fan 20 of the present invention, and its individual components, are shown in FIGS. 1 to 5B. The fan 20 includes a plurality of blades 22 and a spider assembly 24. The illustrated spider assembly 24 includes individual spiders (or center disks) 24A and 24B. In some embodiments, spacers and / or bush portions 26 may be selectively provided. 【0019】 The blades 22 can be configured as separate fan blades. Each of the plurality of blades 22 may include a working portion 22-1 and a base or heel portion 22-2. The working portion 22-1 is used to perform the work of interacting with the fluid to generate an axial cooling flow by the rotation of the fan 20, while the base or heel portion 22-2 is used to mechanically connect each of the plurality of blades 22 to other parts of the modular fan 20. The working portion 22-1 extends in the blade chord direction between the leading edge LE and the trailing edge TE, and extends in the length direction (or blade width direction) from the base 22-2 to the tip, and has an opposing pressure surface and suction surface. In some embodiments, each blade 22 can be integrally formed so as to integrate the working portion 22-1 with the base 22-2. In the illustrated embodiment, each of the blade bases 22-2 has a fixing opening or fixing hole 22-2F penetrating the opposing front surface 22-2S and back surface 22-2P, and is configured to include a substantially flat mounting pad 22-2A. In a normal embodiment, each of the fixing openings or fixing holes 22-2F is generally cylindrical and has a generally circular outer shape. Further, in some embodiments, the fixing holes 22-2F can be arranged substantially perpendicular to the front surface 22-2S and the back surface 22-2P, or can also be inclined. 【0020】 In the illustrated embodiments, the individual blades 22 are made of composite material, but in alternative embodiments, the blades 22 can also be made of metal or other suitable material. All of the blades 22 in the illustrated embodiments have a relatively efficient blade shape (for example, in the working section 22-1), and all blades 22 have substantially the same configuration. For example, the shape of the blades 22 may be similar to the blades of HTEC® fans available from Horton Incorporated (Rosesville, Minnesota, USA) and / or similar to the blades disclosed in PCT International Publication 2015 / 171446. However, in further embodiments, the blades 22 may also have other shapes and sizes depending on the desired application and the requirements for the cooling system. For example, in less cost-conscious applications, it is not necessary to reduce the thickness or gaps at the outer edge of the spider assembly 24, as considered in PCT International Publication 2015 / 171446. 【0021】 To meet the design objectives for applications with lower cost requirements, in some embodiments, the blade 22 can be injection molded from a polymer material such as a thermoplastic material like nylon. Nylon can selectively contain reinforcing fillers such as glass fibers or carbon fibers to increase the rigidity and strength of the material and the resulting blade 22. Injection molding of the blade 22 is a less time-consuming process compared to compression molding of thermosetting composite materials. Also, because thermoplastic resins have a lower density, the fan assembly can be made lighter. In alternative embodiments, other blade materials and / or manufacturing methods can be used. 【0022】 The modular fan 20 further includes a spider assembly 24 consisting of a plurality of individual spiders (or center discs) 24A and 24B. In the illustrated embodiment, there are two spiders 24A and 24B, consisting of a front spider 24A and a rear spider 24B positioned on either side of the blades 22, and each spider 24A and 24B is substantially identical, such as being structurally identical. However, in further embodiments, it is also possible to use a plurality of spiders having different configurations. Each of the spiders 24A and 24B can be configured substantially as a planar disc and has a center hub 24H which may selectively include a central opening 24C. Spacers and / or bushings 26 can be installed between the spiders 24A and 24B in the central opening 24C and assist in structural support and / or facilitate mounting the modular fan 20 to a drive shaft or other mounting location structure. Each of the spiders 24A and 24B further includes a plurality of arms or legs 24L extending outward from the outer diameter of the hub 24H, generally in the radial direction. Each of the spider legs 24L may include a mounting portion 24L-1 and a connecting portion 24L-2. The mounting portion 24L-1 is generally flat and may be located at the far end (or outer end) of each leg 24L. In the illustrated embodiment, the mounting portion 24L-1 has a generally rectangular shape. A plurality of fixing holes or openings 24L-1F are provided in each mounting portion 24L-1 to facilitate the attachment of one of the blades 22 to each spider leg 24L with a suitable mechanical fastener 28 (e.g., a two-part fastener of rivets, pins and collars, bolts, etc.), as will be further described below. In a typical embodiment, the plurality of fixing holes or openings 24L-1F may each be cylindrical, having a generally circular shape. Furthermore, in some embodiments, the multiple mounting holes 24L-1F can be arranged substantially parallel to each other. Also, in some embodiments, the multiple mounting holes 24L-1F can be arranged approximately perpendicular to the opposing front and back surfaces of the mounting portion 24L-1, or at an angle.Since each of the connecting portions 24L-2 extends between a corresponding one of the plurality of mounting portions 24L-1 and the hub 24H, the plurality of connecting portions 24L-2 can be generally arranged radially so as to structurally connect them between the mounting portion 24L-1 and the hub 24H. Since the connecting portion 24L-2 is twisted, the generally flat mounting portion 24L-1 is also twisted with respect to the center hub 24H, which can be generally flat, and the axial direction. The twist angle established by the connecting portion 24L-2 of the spider leg portion 24L sets the twist angle θ of the mounting portion 24L-1 and the corresponding blade 22 (at least at the base 22-2). The twist angle θ is measured with respect to the center hub 24H and / or with respect to a plane orthogonal to the rotation axis. Usually, the twist angle θ is greater than 0° and less than 90°. In this way, the surface orientation of the mounting portion 24L-1 and the surface orientation of the fixing hole 24L-1F with respect to the rotation axis of the fan 20 can be changed by adjusting the twist angle θ, and both the front spider 24A and the rear spider 24B can have legs 24L twisted in a desired manner for a given application, while the individual parts of the same basic spider can also have legs 24L twisted at different angles for different applications. Thereby, the individual parts of the basic spider are made available within different final fan configurations. 【0023】 As shown in Figure 3A, for example, the fixing holes 22-2F that penetrate the mounting pad 22-2A of a given blade base 22-2 in the illustrated embodiment are arranged in an array (FA) defined by a parallelogram outline of a rhombic or rhombic shape (schematically shown for reference by dashed lines). More generally, the pattern of the array FA of fixing holes 22-2F in the mounting pad 22-2A may be asymmetrical with respect to a radial line RA that penetrates the center of the array FA, ​​i.e., the array FA may be asymmetrical in the circumferential direction. More specifically, as shown in Figure 3A, the mounting pad 22-2A is provided with a total of six fixing holes 22-2F that penetrate the mounting pad 22-2A and are arranged in two parallel, substantially linear rows FR1 and FR2 (schematically shown for reference by dashed lines). Rows FR1 and FR2 are positioned obliquely to the radial, blade length, or blade width directions on the one hand, and also obliquely to the blade chord, circumferential, or tangential directions (or directions perpendicular to the radial direction) on the other hand. Rows FR1 and FR2 of the fixing holes 22-2F of the mounting pad 22-2A are positioned at an angle D greater than 0° and less than 90°, and approximately 45°, with respect to an axis perpendicular to the radial direction (or blade length direction). As shown in Figure 3A, which illustrates the back or pressure surface of the blade 22, the angle D is inclined toward the leading edge LE of the blade 22. The blade length direction may be the same as the radial direction, but in alternative embodiments, the blade length (or stacking line) may be oriented in a direction other than the radial direction, such as when the blade is mounted to the spider assembly in a direction other than the radial direction. Furthermore, as shown in Figure 3A, the fixing holes 22-2F of the parallel and oblique rows FR1 and FR2 are positioned to align with each other in the radial or blade length direction. In other words, the fixing holes 22-2F of each row FR1 and FR2 can be aligned to parallel projection lines PL (e.g., three projection lines PL) that pass through the corresponding fixing holes 22-2F of the other row FR1 or FR2 and extend perpendicular to the blade length direction or radial direction. The arrangement of the fixing holes 22-2F in the illustrated embodiment is suitable for accommodating the loads applied to the blade 22 and the fasteners 28 (e.g., rivets) during use.Furthermore, configuring the pattern of the array FA of the fixing holes 22-2F asymmetrically in the circumferential direction helps to determine the desired orientation of the blades 22, which can facilitate the manufacture of the fan 20 in situations where it is difficult to distinguish between the leading edge LE and the trailing edge TE. In further embodiments, more or fewer fixing holes 22-2F may be available and they may be arranged in more diagonal rows (along the same parallel projection line PL) and / or along more or fewer parallel projection lines PL, and the angle D may be changed according to the requirements for a particular application. In further embodiments (such as embodiments with more fixing holes 22-2F than shown), the fixing holes 22-2F may have a circumferentially non-linear arrangement with respect to each other, such as being arranged along arc-shaped segments or chevron-shaped segments that are circumferentially symmetric with respect to the radial line RA passing through the central portion of the array FA. 【0024】 As shown in Figure 4A, the fixing holes 24-1F that penetrate the mounting portion 24L-1 of a given spider leg 24L in the illustrated embodiment have more mounting holes or fixing holes 24L-1F than the array FA in the mounting pad 22-2A of the blade 22, and are arranged in array SA (for example, 8 fixing holes 24L-1F and 6 fixing holes 22-2F). This makes it possible to align the fixing holes 22-2F of the mounting pad 22-2A of the blade 22 with the fixing holes 24L-1F of the mounting portion 24L-1 of the spider leg 24L, regardless of the relative front-rear direction of the blade 22 and the spider 24A or 24B, and even in positions where multiple identical spiders 24A and 24B are arranged in a relative different manner. In the illustrated embodiment, the mounting portion 24L-1 of each spider leg 24L has two additional fixing holes 24L-1F relative to the mounting pad 22-2A of the blade 22. More specifically, in the illustrated embodiment, the array of fixing holes SA of each spider leg 24L includes a subset SA1 of fixing holes 24L-1F arranged in the same array pattern (e.g., rhombic or rhombic, parallelogram shape) as the fixing holes 22-2F of the mounting pad 22-2A of the blade 22 when arranged in a given front-rear direction, but has one additional fixing hole or opening 24L-1F' and 24L-1F'' on each side (in the circumferential direction), such as diagonally, of the resulting mounting array SA. In the illustrated embodiment, the resulting pattern of the array of fixing holes 24L-1F in the mounting portion 24L-1 of a given spider leg 24L looks like a repeating pentagon pattern. 【0025】 Mechanical fasteners, such as two-piece fasteners with rivets or pins and collars (e.g., fasteners under the brand name Huckbolt®), are used to secure the individual blades 22 to the corresponding legs 24L of the spiders 24A and 24B. The mechanical fasteners 28 can be made of metal. In the illustrated embodiments, each mechanical fastener 28 has a shaft, pin, or shank portion (at least fully mounted and engaged) and includes head portions or collar portions at both ends. As shown in Figures 5A and 5B, for example, the pattern of the array SA of fastening holes 24L-1F in the mounting portion 24L-1 of the spider legs 24L allows for the manufacture of a modular fan 20 using two identical spiders 24A and 24B by positioning one spider 24A or 24B inverted relative to the other spider 24A or 24B for the forward spider 24A and rear spider 24B. The presence of surplus fixing holes 24L-1F' and 24L-1F'' in the mounting portion 24L-1 of the spider leg 24L means that a subset SA1 of fixing holes 24L-1F in the corresponding legs 24L of the front spider 24A and rear spider 24B aligns with the array FA of fixing holes 22-2F in the mounting pad 22-2A of the corresponding blade 22. In some embodiments, all of the fixing holes 22-2F of the mounting pad 22-2A of the blade 22 are reversed front to back. The mounting holes 24L-1F in the identically configured forward spider 24A and rear spider 24B, which are positioned close together, are alignable. In this case, the additional or surplus mounting holes 24L-1F' and 24L-1F'' of the spiders 24A and 24B are not aligned with any of the corresponding mounting holes 22-2F of the mounting pad 22-2A of the corresponding blade 22 (for example, located outside the outer circumference P of the array FA) and are offset circumferentially from the array subset SA1. For example, in the illustrated embodiment, the mounting holes 24L-1F' and 24L-1F'' at the right corner on the outer circumference and the left corner on the inner circumference of the array SA in the leg portion 24L of the forward spider 24A are blocked and closed by the material of the blade base 22-2 in the mounting pad 22-2A and are not used by the fastener 28 (see Figure 5A).Furthermore, the fixing holes 24L-1F' and 24L-1F'' at the left corner on the outer circumference and the right corner on the inner circumference of the array SA in the leg portion 24L of the rear spider 24B are similarly blocked and closed and not used by the fixing device 28 (see Figure 5B). On the other hand, all of the fixing holes 22-2F of the array FA in the mounting pad 22-2A of the blade 22 are used by the fixing device 28 that connects both the front spider 24A and the rear spider 24B. In addition, the spider leg portion 24L The shielded fixing holes 24L-1F' and 24L-1F'' in one of the given arrays may include at least one of the fixing holes 24L-1F' and 24L-1F'' located laterally on each of the subset SA1 of array SA and on opposite sides of each other in the circumferential direction of the radial line RA. At least some of these shielded fixing holes 24L-1F' and 24L-1F'' can be radially offset from each other at positions spaced apart in the circumferential direction. 【0026】 In the modular fan 20, using multiple spiders 24A and 24B compared to using a single spider allows for a relatively smaller and lighter design while improving strength, rigidity, and durability, making it useful for larger fans. Using identical spiders 24A and 24B in different orientations also reduces the number of unique parts and associated costs in the manufacture of the modular fan 20. The absence of unused mounting holes 22-2F in the blade base 22-2 can help improve blade length and reduce areas of concern for stress concentration and / or crack formation. In addition, mechanically fixing the spiders 24A and 24B onto the blade base 22-2 (e.g., by riveting) eliminates the need to fix the overmolded insert (e.g., by riveting), thereby reducing the number of blade parts, overall assembly complexity, and / or manufacturing complexity, contributing to overall cost reduction. Those skilled in the art will recognize many other features and advantages when considering the entire disclosure. 【0027】 Consideration of Possible Embodiments 【0028】 A modular axial fan may include a plurality of blades, each of which has a working section and a base with a mounting pad; each of the mounting pads having a plurality of blade fixing holes arranged in an array (FA); a spider assembly having a forward spider and a rear spider; a forward spider and a rear spider having the same structural configuration; each of the forward spider and rear spider having a center hub and a plurality of legs extending from the center hub; each of the plurality of legs having a plurality of leg fixing holes arranged in an array (SA); and a plurality of mechanical fasteners for fixing each of the plurality of blades to a corresponding leg of each of the legs of the forward spider and rear spider, such that one of the plurality of mechanical fasteners is fixed to each of the plurality of blade fixing holes in each of the arrays (FA) of the plurality of blades. Here, each of the arrays (FA) of multiple blade fixing holes for each of the multiple blades is circumferentially asymmetric, and multiple mechanical fasteners are fixed to a subset (SA1) of the leg fixing holes of the array (SA) at each leg of the forward spider and rear spider, and the subset (SA1) of the leg fixing holes of each array (SA) of the leg is aligned with the array (FA) of one of the multiple blades, and at least two of the leg fixing holes of each leg of the forward spider and rear spider are circumferentially offset from the subset (SA1) of leg fixing holes and are blocked by the base of the corresponding one of the multiple blades and are not used for any of the multiple mechanical fasteners. 【0029】 The modular axial fan described in the preceding paragraph may optionally, additionally and / or alternatively, include one or more of the following features, configurations, and / or additional components: 【0030】 Each of the multiple blades can be formed from a polymer. 【0031】 Both the forward and rear spiders can be formed from metallic material. 【0032】 Each leg of the forward and rear spiders can have only two unused leg mounting holes, and these two leg mounting holes are located one on each side of the circumferential direction of the subset (SA1). 【0033】 At least two of the multiple unused leg mounting holes in the legs of the front and rear spiders can be offset radially from each other. 【0034】 Each of the arrays (FAs) of blade fixing holes in the multiple blades is defined by the outline of a parallelogram that is either rhombic or rhombic. 【0035】 The multiple blade mounting holes in each array (FA) of multiple blades may be arranged in multiple parallel rows oblique to both the blade length direction and the blade string direction. 【0036】 Multiple parallel rows of blade fixing holes can be arranged so as to be linearly aligned with each other in the direction of the blade length. 【0037】 An array (FA) of multiple blade mounting holes for each of the multiple blades may contain as few as six mounting holes. 【0038】 The array (SA) of multiple leg mounting holes on each leg of the forward and rear spider may contain as few as eight mounting holes. 【0039】 The mounting pads at the base of each blade may be flat. 【0040】 The legs of the front and rear spiders may have a flat mounting portion and a twisted connecting portion, and each leg of the connecting portion may be located radially between the mounting portion and the center hub. 【0041】 The center hubs of the front spider and rear spider may each have a central opening. 【0042】 The spider assembly may further include spacers positioned along the central opening between the front spider and the rear spider. 【0043】 The forward and rear spiders may be positioned so that they are inverted relative to each other. 【0044】 The modular fan comprises multiple blades, each of which has a base with a mounting pad that is generally flat with the working part; each mounting pad having multiple blade fixing holes arranged in an array (FA) defined by a parallelogram outer shape of either a rhombic or rhombic shape; a spider assembly having a front spider and a rear spider; each front spider and rear spider having the same structural form; each front spider and rear spider having a center hub and multiple legs extending from the center hub; and each leg having multiple leg fixing holes arranged in an array (SA). The present invention may include: a plurality of legs, each having a flat mounting portion and a twisted connecting portion; an array (SA) comprising a subset (SA1) of leg fixing holes and at least one additional fixing hole on the circumferentially opposite side of the subset (SA1); and a plurality of mechanical fasteners for fixing each of the plurality of blades to a corresponding leg of each of the legs of the front spider and rear spider, such that one of the plurality of mechanical fasteners passes through each of the plurality of blade fixing holes in each array (FA) of the plurality of blades and through each of the fixing holes in the subset (SA1). Here, the at least one additional fixing hole on the circumferentially opposite side of the subset (SA1) is blocked by the base of the corresponding blade of the plurality of blades and is not used by any of the plurality of mechanical fasteners, and the first hole of the at least one additional fixing hole on one side of the subset (SA1) is radially offset from the second hole of the at least one additional fixing hole on the opposite side of the subset (SA1). 【0045】 The modular fan described in the preceding paragraph may optionally, additionally and / or alternatively, include one or more of the following features, configurations, and / or additional components: 【0046】 Each of the multiple blades can be formed from a polymer. 【0047】 Both the forward and rear spiders can be formed from metallic material. 【0048】 The multiple blade mounting holes in each array (FA) of multiple blades may be arranged in multiple parallel rows oblique to both the blade length direction and the blade string direction. 【0049】 Multiple parallel rows of blade fixing holes can be arranged so as to be linearly aligned with each other in the direction of the blade length. 【0050】 Each of the arrays (FA) of multiple blade mounting holes on multiple blades may include at least six mounting holes arranged in multiple rows. 【0051】 A method for manufacturing an axial flow fan includes (a) arranging a front spider adjacent to a rear spider so that they are inverted front to back, wherein the front spider and the rear spider have the same structural configuration for each leg, which is provided with a plurality of radially extending legs and a plurality of leg fixing holes arranged in an array (SA), and the array (SA) includes leg fixing holes that constitute a subset (SA1) of the plurality of leg fixing holes and at least one additional fixing hole on each side in the circumferential direction of the subset (SA1); and (b) arranging a blade between a first leg of the plurality of legs of the front spider and a first leg of the plurality of legs of the rear spider, wherein the blade is provided with a plurality of blade fixing holes arranged in an array (FA) via mounting pads, and the blade is arranged such that the subset (SA1) of the plurality of leg fixing holes aligns with the plurality of blade fixing holes of the array (FA), and at least one additional fixing hole on each side of the subset (SA1) is in the array ( The process may include: (c) a step located outside the array (FA) and shielded by the blade material; (d) a step of securing the blade to the first legs of both the forward spider and the rear spider with a plurality of mechanical fasteners, one of which passes through each of the plurality of blade fasteners of the array (FA), and each of the plurality of mechanical fasteners passing through one of the plurality of blade fasteners of the array (FA) also passes through one of the plurality of leg fasteners constituting a subset (SA1) in the first legs of each of the forward spider and the rear spider, and each of the at least one additional fastener on each side of the subset (SA1) is not used by the plurality of mechanical fasteners passing through one of the plurality of blade fasteners of the array (FA); and (d) a step of repeating steps (b) and (c) for an additional blade until one of the additional blades is secured to the remaining leg of each of the forward spider and the rear spider. 【0052】 The manufacturing method described in the preceding paragraph may optionally include, additionally and / or alternatively, one or more of the following features, configurations, and / or additional components: 【0053】 The repetition of steps (b) and (c) by step (d) can be performed simultaneously or sequentially. 【0054】 A step of twisting each of a plurality of legs relative to the hub of the respective front spider or rear spider, wherein each leg has a flat mounting portion positioned at the twisting angle. 【0055】 The step of injection molding the blade with nylon. 【0056】 Steps to form the front spider and rear spider from a metal material. 【0057】 summary 【0058】 Any relative or degree terms used herein, such as “substantially,” “basically,” “generally,” and “about,” should be interpreted in accordance with and subject to any applicable definitions or limitations expressly stated herein. In all cases, any relative or degree terms used herein should be interpreted broadly to encompass the relevant disclosed embodiments and the ranges and variations understood by those skilled in the art in consideration of the entire disclosure, such as normal acceptable manufacturing variations, accidental alignment variations, transient alignment or shape variations induced by thermal, rotational, or vibrational operating conditions, and transient signal variations. Furthermore, any relative or degree terms used herein should be interpreted to encompass a range that expressly includes, without variation, a specified quality, characteristic, parameter, or value, as if no restrictive relative or degree terms were used in the given disclosure or description. 【0059】 The word “comprise,” or variations such as “comprises” or “comprising,” are used non-exclusively herein and should be interpreted as including, but not excluding, any other elements, features, or steps, or any other elements, features, or steps, as described herein. Furthermore, unless expressly limited, the use of the word “comprise,” or variations thereof, does not exclude any additional elements, steps, or groups of elements or steps not described in isolation. Furthermore, unless expressly limited, the words “a” and “an” as used herein refer to one or more, and do not limit the identified elements, features, steps, etc., to just one. However, the use of the words “a” and “an” herein should be interpreted subject to and contingent upon any further applicable limitations expressly stated in the context of a particular use, and not to extend any limitations specific to such contexts to all other uses in a general sense. 【0060】 While the present invention has been described with reference to preferred embodiments, those skilled in the art will recognize that modifications can be made in form and detail without departing from the idea and scope of the present invention.

Claims

[Claim 1] A plurality of blades, each of which includes a working portion and a base portion having a mounting pad, and each of the mounting pads is provided with a plurality of blade fixing holes arranged in an array (FA), A spider assembly having a front spider and a rear spider, wherein the front spider and the rear spider have the same structural form, each of the front spider and the rear spider has a center hub and a plurality of legs extending from the center hub, and each of the plurality of legs is provided with a plurality of leg fixing holes arranged in an array (SA), The present invention comprises a plurality of mechanical fasteners, each of which is fixed to a corresponding leg of the front spider and the rear spider, such that one of the plurality of mechanical fasteners is fixed to each of the plurality of blade fixing holes in each of the plurality of blade arrays (FA) of the plurality of blades, Each of the arrays (FA) of the multiple blade fixing holes of each of the multiple blades is asymmetrical in the circumferential direction. The plurality of mechanical fasteners are fixed to the respective legs of the front spider and the rear spider in a subset (SA1) of the leg fixing holes of the array (SA), and each of the subsets (SA1) of the leg fixing holes of the array (SA) of the leg is aligned with the array (FA) of the plurality of blade fixing holes of a corresponding blade among the plurality of blades. A modular axial fan in which at least two of the plurality of leg fixing holes in each leg of the front spider and the rear spider are offset circumferentially from a subset of the leg fixing holes (SA1) and are shielded by the base of a corresponding blade of the plurality of blades and are not used in any of the plurality of mechanical fixtures. [Claim 2] A modular axial fan according to claim 1, wherein each of the plurality of blades is made of polymer, and each of the forward spider and the rear spider is made of a metal material. [Claim 3] The modular axial flow fan according to claim 1, wherein each of the legs of the front spider and the rear spider has only two unused leg fixing holes, and the two leg fixing holes are located one on each side of the subset (SA1) in the circumferential direction. [Claim 4] The modular axial fan according to claim 1, wherein at least two of the plurality of unused leg fixing holes in the legs of the front spider and the rear spider are offset from each other in the radial direction. [Claim 5] The modular axial flow fan according to claim 1, wherein each of the arrays (FA) of the plurality of blade fixing holes of the plurality of blades is defined by a parallelogram outer shape that is either rhombic or rhombic. [Claim 6] The modular axial flow fan according to claim 1, wherein the plurality of blade fixing holes of each of the arrays (FA) of the plurality of blades are arranged in a plurality of parallel rows oblique to both the blade length direction and the blade chord direction. [Claim 7] The modular axial flow fan according to claim 6, wherein the plurality of parallel rows of blade fixing holes are arranged to be linearly aligned with each other in the direction of the blade length. [Claim 8] The modular axial fan according to claim 1, wherein each of the arrays (FA) of the multiple blade fixing holes of the multiple blades includes only six fixing holes. [Claim 9] The modular axial fan according to claim 8, wherein the array (SA) of the plurality of leg fixing holes on each leg of the front spider and the rear spider includes only eight fixing holes. [Claim 10] The modular axial fan according to claim 1, wherein the mounting pads at the base of each of the blades are flat. [Claim 11] The modular axial flow fan according to claim 1, wherein the legs of the front spider and the rear spider have a flat mounting portion and a twisted connecting portion, and each leg of the connecting portion is located radially between the mounting portion and the center hub. [Claim 12] The modular axial flow fan according to claim 1, wherein the center hubs of the front spider and the rear spider each have a central opening, and the spider assembly further comprises spacers positioned between the front spider and the rear spider along the central opening. [Claim 13] The modular axial flow fan according to claim 1, wherein the front spider and the rear spider are arranged so as to be reversed in front of each other. [Claim 14] A plurality of blades, each including a base having a mounting pad that is generally flat with the working portion, wherein each mounting pad is provided with a plurality of blade fixing holes arranged in an array (FA) defined by a parallelogram outer shape that is either rhombic or rhombic, A spider assembly having a front spider and a rear spider, wherein the front spider and the rear spider have the same structural configuration, each of the front spider and the rear spider has a center hub and a plurality of legs extending from the center hub, each of the plurality of legs is provided with a plurality of leg fixing holes arranged in an array (SA), each of the plurality of legs has a flat mounting portion and a twisted connecting portion, and the array (SA) includes leg fixing holes constituting a subset (SA1) of the plurality of leg fixing holes and at least one additional fixing hole on the opposite side of the subset (SA1) in the circumferential direction, A modular fan comprising a plurality of mechanical fasteners for securing each of the plurality of blades to one of the legs of the front spider and the rear spider, wherein one of the plurality of mechanical fasteners penetrates each of the plurality of blade fastening holes in each of the arrays (FA) of the plurality of blades and also penetrates the fastening holes of the subset (SA1), and at least one additional fastening hole on the opposite side of the subset (SA1) in the circumferential direction is blocked by the base of a corresponding blade of the plurality of blades and is not used in any of the plurality of mechanical fasteners, and the first hole of the at least one additional fastening hole on one side of the subset (SA1) is radially offset from the second hole of the at least one additional fastening hole on the opposite side of the subset (SA1). [Claim 15] The modular fan according to claim 14, wherein each of the plurality of blades is made of polymer, and each of the front spider and the rear spider is made of a metal material. [Claim 16] The modular fan according to claim 14, wherein the plurality of blade fixing holes of each of the arrays (FA) of the plurality of blades are arranged in a plurality of parallel rows oblique to both the blade length direction and the blade chord direction. [Claim 17] The modular fan according to claim 16, wherein the plurality of parallel rows of blade fixing holes are arranged to be linearly aligned with each other in the direction of the blade length. [Claim 18] The modular fan according to claim 14, wherein each of the arrays (FA) of the plurality of blade fixing holes of the plurality of blades includes at least six fixing holes arranged in multiple rows. [Claim 19] (a) A step of arranging a front spider adjacent to a rear spider so that they are inverted front to back, wherein the front spider and the rear spider have the same structural configuration for each leg, which is provided with a plurality of radially extending legs and a plurality of leg fixing holes arranged in an array (SA), and the array (SA) includes leg fixing holes that constitute a subset (SA1) of the plurality of leg fixing holes and at least one additional fixing hole located laterally in the circumferential direction of each subset (SA1), (b) A step of positioning a blade between a first leg of a plurality of legs of the forward spider and a first leg of a plurality of legs of the rear spider, wherein the blade is provided with a plurality of blade fixing holes arranged in an array (FA) via mounting pads, the blade is positioned such that a subset (SA1) of the plurality of leg fixing holes aligns with the plurality of blade fixing holes in the array (FA), and at least one additional fixing hole on each side of the subset (SA1) is located outside the array (FA) and is shielded by the blade material, (c) A step of securing the blade to the first legs of both the front spider and the rear spider with a plurality of mechanical fasteners, wherein one of the plurality of mechanical fasteners penetrates each of the plurality of blade fixing holes of the array (FA), and each of the plurality of mechanical fasteners penetrating one of the plurality of blade fixing holes of the array (FA) also penetrates one of the plurality of leg fixing holes constituting the subset (SA1) in the first legs of each of the front spider and the rear spider, and each of the at least one additional fixing hole on each side of the subset (SA1) is not used by the plurality of mechanical fasteners penetrating one of the plurality of blade fixing holes of the array (FA), (d) A method for manufacturing an axial flow fan, comprising the step of repeating steps (b) and (c) with respect to an additional blade until one of the additional blades is fixed to the remaining legs of the front spider and the rear spider, respectively. [Claim 20] A method for manufacturing an axial flow fan according to claim 19, further comprising the step of twisting each of the plurality of legs with respect to the hub of the respective front spider or rear spider, the step of having a flat mounting portion arranged at the angle of the twist of each leg. [Claim 21] The steps include: injection molding the aforementioned blade with nylon, A method for manufacturing an axial flow fan according to claim 19, comprising the step of forming the forward spider and the rear spider from a metal material.

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