Strip cooling fan belt with improved bond line strength

Abstract

The fan includes a hub configured to be driven by a motor to rotate about a fan rotational axis, blades projecting radially from the hub, and a band surrounding the rotational axis and connecting tips of the blades. The band includes thickened regions of structural reinforcement that project from an outer surface of the band in a direction away from the hub. The thickened regions are disposed between respective tips of each pair of adjacent blades. Each thickened portion bridges a joint line of the band.

Description

Technical Field

[0001] This invention relates to a strip cooling fan belt with improved bonding line strength. Background Technology

[0002] Automobiles typically require one or more airflow fans to help transfer heat through one or more heat exchangers. For example, axial fans can be used for automotive cooling, and they include a hub connected to a motor shaft, multiple blades projecting from the outer circumference of the hub, and a belt connecting the blade tips to prevent blade deformation.

[0003] Such fans are typically mass-produced via a plastic injection molding process, in which molten plastic is injected into the mold of fan 100 near the hub-forming portion (Figure 1). From one or more injection points 101, the molten plastic (indicated by arrows) flows radially outward from the hub-forming portion through the blade-forming portion within the mold cavity, and then circumferentially along the belt-forming portion. When the two flow fronts meet within the belt-forming portion, a weld line 150 is formed in the resulting fan belt 120. The weld line 150 is formed approximately at the midpoint between each pair of adjacent fan blades 140 in the belt 120. The weld line 150 is typically weaker than other areas of the belt 120 without the weld line 150, and may therefore be an initial point of failure within the fan 100.

[0004] The bond line strength of a fan-shaped strip can be improved simply by increasing its thickness. However, as the thickness increases, the mass of the strip increases, and therefore the centrifugal stress increases. Furthermore, from a molding best practice perspective, increasing the mass of injection-molded parts located far from the injection point is undesirable. Summary of the Invention

[0005] In some aspects, the ribbon fan includes structurally reinforced bonding lines that improve the strength of the ribbon bonding area, thereby increasing the overall structural strength of the fan.

[0006] To increase the stiffness and strength of the fan belt between the fan blades, the fan belt includes regions with increased radial thickness (referred to as "thickened areas") where the fan belt joint line appears. These regions are located on the outward-facing surface of the cylindrical portion of the fan belt. Each thickened area projects outward away from the hub and extends circumferentially across (or "bridges") the joint line. Each thickened area is configured to have a smooth transition to the rest of the outward-facing surface of the belt, and its dimensions are designed to reduce stress in the belt while ensuring that the joint line is bridged and adequately reinforced.

[0007] By providing localized areas of increased thickness, the strength of the fan belt bond line is improved while minimizing the increase in belt mass, and thus also minimizing the corresponding increase in centrifugal stress. Furthermore, by limiting the increase in belt thickness to (1) the cylindrical portion of the belt and (2) the belt region not radially aligned with the fan blades, the undesirable effects of increasing belt thickness are minimized. This strategy of increasing thickness increases the strength of weak belt bond lines, and does so effectively by avoiding adding mass where it would not increase bond strength.

[0008] In some aspects, the fan includes a hub configured to be driven by a motor to rotate about a fan rotation line, and a belt surrounding the rotation axis and concentric with the hub. The belt includes a front end facing the direction of airflow through the fan and a rear end opposite the front end. The fan includes blades projecting radially from the hub. Each blade has a root connected to the hub and a tip connected to a hub-facing surface of the belt. For each location along a line extending circumference around the belt, the distance between the fan rotation axis and the belt is constant, wherein the line is positioned on the hub-facing surface of the belt at the rear end. Furthermore, the radial dimension of the belt is non-uniform along the line.

[0009] In some embodiments, the strip includes a cylindrical portion, a lip portion, and a middle portion. The cylindrical portion extends parallel to the fan rotation axis and includes a rear end of the strip. The lip portion extends at an angle relative to the fan rotation axis. The surface of the lip portion includes a front end of the strip. The middle portion connects one end of the cylindrical portion to one end of the lip portion. The tip of each blade engages with the cylindrical portion along a corresponding blade tip region. The cylindrical portion includes a first region of a line having a first radial dimension and a second region of a line having a second radial dimension. The second radial dimension is smaller than the first radial dimension. The first region of the line is disposed between corresponding blade tip regions of the tips of a pair of adjacent blades, and the second region of the line is radially aligned with the corresponding blade tip regions.

[0010] In some embodiments, the first radial dimension is larger than the axial dimension of the lip portion.

[0011] In some embodiments, the first radial dimension is at least five percent larger than the second radial dimension.

[0012] In some embodiments, the size of the middle portion is not uniform along the circumference of the strip, such that the size of the middle portion at a position radially aligned with the first region of the line is larger than the corresponding size of the middle portion at a position radially aligned with the second region of the line.

[0013] In some embodiments, the cylindrical portion includes a third region of the line having a tapered radial dimension. The third region of the line provides a transition between the first region and the second region of the line, wherein the circumference of each third region of the line is at least as long as the circumference of the first region of its adjacent line.

[0014] In some embodiments, the cylindrical portion includes a third region of a line having a tapered radial dimension. The third region of the line provides a transition between the first region and the second region of the line, wherein the sum of the circumferential dimensions of one of the first regions of the line and the respective adjacent third regions of the line is at least fifty percent of the distance between adjacent blade tips.

[0015] In some embodiments, the radial dimension of the belt is non-uniform along the line, such that the radial dimension varies periodically along the circumference of the belt. Furthermore, the radial dimension is largest between adjacent blades and smallest at locations aligned with the blades.

[0016] In some embodiments, the strip includes a cylindrical portion, a lip portion, and a middle portion. The cylindrical portion extends parallel to the fan's rotation axis and includes a front end of the strip. The lip portion extends at an angle relative to the fan's rotation axis. The surface of the lip portion includes a rear end of the strip. The middle portion connects one end of the cylindrical portion to one end of the lip portion. The tip of each blade engages with the cylindrical portion along a corresponding blade tip region. The cylindrical portion includes a first region of a line having a first radial dimension and a second region of a line having a second radial dimension. The second radial dimension is smaller than the first radial dimension. The first region of the line is disposed between corresponding blade tip regions of the tips of a pair of adjacent blades. Furthermore, the second region of the line is radially aligned with the corresponding blade tip region.

[0017] In some aspects, the fan includes a hub configured to be driven by a motor to rotate about a fan rotation line, and a belt surrounding the rotation axis and concentric with the hub. The belt includes a front end facing the direction of airflow through the fan and a rear end opposite the front end. The fan includes blades projecting radially from the hub, each blade including a root connected to the hub and a tip connected to a hub-facing surface of the belt. For each location along a line extending circumference around the belt, the distance between the fan rotation axis and the belt is constant, wherein the line is positioned on the hub-facing surface of the belt at the rear end. The radial dimension of the belt is non-uniform along the line, such that the radial dimension varies periodically along the circumference of the belt, and the radial dimension has a maximum value at locations between adjacent blades and a minimum value at locations aligned with the blades. Attached Figure Description

[0018] Figure 1 is a schematic top view of a strip cooling fan, marked as follows: a) circles identify the injection location of molten plastic during the fan's injection molding process; b) arrows indicate the flow direction of molten plastic through the mold cavity during the injection molding process; and c) dashed lines indicate the location of the joint line between adjacent fan blade pairs.

[0019] Figure 2This is a perspective view of a portion of a strip cooling fan that includes a reinforced, thickened area, where dashed lines indicate the location of the junction lines between adjacent pairs of fan blades.

[0020] Figure 3 for Figure 2 A perspective view of a portion of a strip cooling fan, illustrating the strip with a cut-off portion showing the cross-section of the strip at the joint line and the cross-section of the strip in the blade tip region.

[0021] Figure 4 for Figure 3 In China, it is called " Figure 4 A cross-sectional view of the band at the location of "".

[0022] Figure 5 for Figure 3 In China, it is called " Figure 5 A cross-sectional view of the band at the location of "".

[0023] Figure 6 For along Figure 7 The cross-sectional view of the band seen by line AA.

[0024] Figure 7 Bottom plan view of part of the fan.

[0025] Figure 8 for Figure 2 A side cross-sectional view of a portion of the fan.

[0026] Figure 9 This is a side cross-sectional view of a portion of the fan in an alternative embodiment.

[0027] Figure 10 A side cross-sectional view of a portion of the fan in another alternative embodiment.

[0028] Figure 11 This is a side cross-sectional view of a portion of the fan in another alternative embodiment. Detailed Implementation

[0029] refer to Figure 2-8 An axial fan 1, used for cooling heat exchange media passing through a heat exchanger such as that of an automotive radiator, is provided with a hub 2 coupled to a drive source (not shown), such as a motor. The fan 1 includes a plurality of blades 40 projecting radially outward from the hub 2. Furthermore, the fan 1 includes a belt 20 surrounding the hub and connecting the tips 42 of each blade 40 to prevent deformation of the blades 40. The hub 2, blades 40, and belt 20 are formed as a single piece, for example, in an injection molding process. The fan 1 rotates by a rotational force transmitted from the motor to the hub 2. In the illustrated embodiment, the fan 1 is relative to... Figure 2The view shown is rotated clockwise about the fan rotation axis 10, and the airflow direction, indicated by arrow A, is parallel to the fan rotation axis 10. The belt 20 includes a thickened region 160, which reduces belt stress and increases the structural integrity of the belt 20 near the joint line 150. The thickened region 160 will be described in detail below.

[0030] Hub 2 is a hollow cylinder, which is closed at one end by an end surface 6 perpendicular to the fan rotation axis 10. The outer circumference 4 of hub 2 faces the belt 20.

[0031] Each blade 40 includes a root 44 connected to the belt-facing surface 4 of the hub 2, and a tip 42 spaced apart from the root 44. Each tip 42 is connected to the hub-facing surface 24 of the belt 20. The airflow guiding surface of each blade 40 has a complex three-dimensional curvature, which is determined by the requirements of the specific application. The blade configuration, including the number of blades 40 used in the fan 1, the shape of the blades 40, the blade spacing, etc., is also determined by the requirements of the specific application.

[0032] The direction of the airflow discharged from fan 1 depends at least in part on the blade curvature and includes a substantially axial flow component. As used herein, the term "axial flow component" refers to the component of the airflow that flows in a direction parallel to the fan's axis of rotation 10.

[0033] The belt 20 is typically an L-shaped circumferential ring concentric with and radially spaced outward from the hub 2. Specifically, the belt 20 includes a cylindrical portion 22 corresponding to one leg of the L-shape and extending parallel to the fan rotation axis 10. The belt 20 includes a lip portion 30 corresponding to the other leg of the L-shape and extending at an angle to the fan rotation axis 10. In the illustrated embodiment, the lip portion 30 is perpendicular to the cylindrical portion 22 and provides a front end 25 of the belt 20 relative to the airflow direction A through the fan 1. Furthermore, the belt 20 includes a curved intermediate portion 28 that connects one end of the cylindrical portion 22 to one end of the lip portion 30. The cylindrical portion 22 surrounds the hub 2, and the lip portion 30 projects out of the cylindrical portion 22 in a direction away from the hub 2.

[0034] The belt 20 has a first surface 21 that faces and comes into contact with the air flowing through the fan 1, and a second surface 23 that is opposite to the first surface. Therefore, the hub-facing surface 24 of the cylindrical portion 22 provides a portion of the first surface 21.

[0035] Each blade tip 42 joins the hub-facing surface 24 of the cylindrical portion 22 along a circumferentially extending region along the cylindrical portion 22, referred to as the "blade tip region" 48.

[0036] The cylindrical portion 22 of band 20 includes a structurally reinforced thickened region 160 projecting from the second surface 23. As used herein, references to the thickness of band 20 correspond to the distance between the first surface 21 and the second surface 23. Within the cylindrical portion 22, the thickness of band 20 corresponds to the radial dimension of band 20, while within the lip portion 30, the thickness of band 20 corresponds to the axial dimension of band 20.

[0037] Since fan 1 is injection molded, fan 1 includes structures that facilitate the injection molding manufacturing process. For example, hub 2 and belt 20 may have draft angles that allow fan 1 to be removed from the mold. In another example, the surfaces of hub 2 and belt 20 facing each other may include flow-stop valves that control the flow of molten plastic within the mold near the parting line. Although belt 20 includes features required for manufacturing purposes and affecting the thickness of belt 20, such as draft and flow-stop valves, these manufacturing-related features do not reinforce the joint line 150 and are not considered part of the thickened region 160. Since manufacturing-related features, such as draft and flow-stop valves, do not extend to the rear end 29 of the belt (e.g., the most downstream end of belt 20 relative to the airflow direction A through fan 1), the thickened region 160 may be defined relative to a line 180 extending circumferentially around the belt, wherein line 180 is disposed on the hub-facing surface 24 of belt 20 at the rear end 29. Specifically, for each location along line 180, the distance 12 between the fan rotation axis 10 and the hub-facing surface 24 of the band 20 is constant, and the radial dimension of the band 20 is non-uniform along line 180. That is, the thickened region 160 corresponds to the protrusion from the second surface 23 of the band. It should be understood that the thickened region 160 is not limited to line 180 and extends axially between the lip 30 and the rear end 29.

[0038] Each thickened region 160 has a thickness t1 at a location spaced apart (e.g., between) from the thickened region 160 that is greater than the thickness t2 of the cylindrical portion 22. Specifically, the portion of the cylindrical portion 22 radially aligned with the blade tip region 48 does not provide additional thickness and is referred to as the non-thickened region 162. In the non-thickened region 162, the cylindrical portion 22, the intermediate portion 28, and the lip portion 30 each have a thickness t2. In the illustrated embodiment, the thickness t2 of the non-thickened region 162 is equal to the thickness t of the lip portion 30. 唇 Although the thickened region 160 may extend axially (e.g., in a direction parallel to the fan rotation axis 10) into a portion of the curved intermediate portion 28, the lip portion 30 of the band 20 is not thickened and has a uniform thickness t on the circumference of the band 20. 唇 .

[0039] In some embodiments, the thickness t1 of the thickened region 160 is at least 5 percent greater than the thickness t2 of the non-thickened region 162. In other embodiments, the thickness t1 of the thickened region 160 is at least 10 percent, 20 percent, 30 percent, 40 percent, 50 percent, or 60 percent greater than the thickness t2 of the non-thickened region 162. The thickness t1 of the thickened region 160 is determined based on the requirements of the specific application, while improving the bonding strength and minimizing the increase in tape mass, and therefore also minimizing the corresponding increase in centrifugal stress.

[0040] The band 20 includes a thickened region 160 disposed between each pair of adjacent blades 40, such that a single thickened region 160 is disposed between each pair of adjacent blades 40. In the illustrated embodiment, the number of thickened regions 160 is equal to the number of blades 40.

[0041] A thickened region 160 is disposed between the respective tips 42 of an adjacent pair of blades 40. In the illustrated embodiment, the thickened region 160 is disposed at an intermediate position between the respective tips 42 of an adjacent pair of blades 40 so as to extend through the corresponding bonding line 150. However, in applications where the bonding line 150 is not disposed at an intermediate position between the respective tips 42, such as that may occur in fans with unequal blade spacing, it should be understood that the thickened region 160 may be offset toward one of the blades in the adjacent blade pair in order to bridge the bonding line 150.

[0042] Each thickened region 160 extends circumferentially. In some embodiments, the circumferential dimension c1 of each thickened region 160 is in the range of 5% to 50% of the inter-blade arc length c2, wherein the inter-blade arc length corresponds to the distance between the respective tips 42 or blade tip regions 48 of adjacent blades 40 along the surface 24 facing the hub.

[0043] The cylindrical portion 22 with 20 includes a transition region 164 disposed between each thickened region 160 and the adjacent blade tip 42. In some embodiments, the sum of the circumferential dimension c1 of each thickened region 160 and the circumferential dimension c3 of the adjacent transition region 164 is in the range of 50% to 100% of the inter-blade arc length c2.

[0044] exist Figure 2-8 In the illustrated embodiment, the circumferential dimension c3 of each transition region 164 adjacent to the thickened region 160 is approximately the same as the circumferential dimension c1 of the thickened region 160, and each region 164, 160, 164 extends along approximately one-third of the inter-blade arc length c2. In other embodiments, the thickened region 160 may not extend circumferentially, since the maximum thickness may occur on a single line with essentially zero width (e.g., in this case, the circumferential dimension c1 of each thickened region 160 is close to zero), and the transition regions 164 may be relatively large, such that the thickness change is very gradual in the inter-blade space.

[0045] Therefore, the cylindrical portion 22 has a non-uniform thickness along the circumference of the belt 20, causing the thickness to vary periodically along the circumference of the belt. Furthermore, the cylindrical portion 22 has the maximum thickness between adjacent blades 40 and the minimum thickness at the position aligned with the blades 40.

[0046] The thickened region 160 is discreet, with its thickness t1 being at most 20 percent of the blade span 46, which corresponds to the distance between the root 44 and tip 42 of one of the blades 40. This configuration minimizes the fan diameter and improves packaging flexibility. In some applications, such as engine cooling, engine cooling fans may have a thickened region 160, where the thickness t1 can be in the range of two to three percent of the blade span 46. Because the thickened region 160 has a relatively large circumferential range, it ensures that each bonding line 150 will be located within the radial protrusion of the thickened region 160. This, in turn, ensures that the thickened region 160 appropriately reinforces the corresponding bonding line 150, even with relatively large variations in the position of the plastic injection during the manufacturing process.

[0047] By providing a thickened region 160 on the second surface 23 of the belt 20, the flow loss of air through the fan 1 is minimized.

[0048] The thickened area 160 on belt 20 is not limited to the fan 1 with a downstream stator design, such as Figure 2-8 As shown, a stator (not shown) supports a motor (not shown) that drives a fan 1 via a hub 2. In the downstream stator design, the stator is positioned downstream of the fan 1 relative to the airflow direction A through the fan 1. In the downstream stator design, a lip portion 30 provides the front end 25 of the band 20. A thickened region 160 can be used to reinforce the band bonding line 150 in the fan 201 with the upstream stator design, as... Figure 9 As shown. In the upstream design, the stator is positioned upstream of fan 201 relative to the airflow direction A through fan 201. Figure 9 In the middle, the lip portion 30 provides a front end 25 with 220. In the alternative fan 301 with an upstream stator design ( Figure 10 In the ), the lip portion 30 provides a rear end 29 with 320. Although as Figure 8-10 As shown, the lip portion 30 may extend in a direction perpendicular to the fan rotation axis 10, but the lip portion 10 is not limited to this configuration. For example, in some embodiments, the lip portion 30 may extend at an acute angle relative to the fan rotation axis 10, such as... Figure 11 The alternative upstream stator design fan 401 described is in band 420, or shown in the downstream stator design fan (not shown).

[0049] Although Figure 2-11 The cooling fan described herein is a car cooling fan, but Figure 2-11 The cooling fans described herein are not limited to automotive applications. For example, cooling fans can be used in computers to cool hard drives, and in heating and ventilation units to cool compressors, etc. Furthermore, Figure 2-11 The cooling fan described is not limited to cooling applications.

[0050] Selective illustrative embodiments of the fan are described in some details above. It should be understood that only structures deemed necessary to make the fan clear are described herein. Other conventional structures and components of those fan accessories and auxiliary parts are considered to be known and understood by those skilled in the art. Furthermore, while operational examples of the fan have been described above, the fan is not limited to the above operational examples, but various design modifications can be made without departing from the fan set forth in the claims.

Claims

1. A fan, the fan comprising: Hub, which is configured to be driven by a motor to rotate about the fan's rotation axis; A belt, the belt being around the axis of rotation and concentric with the hub, the belt including a front end facing the direction of airflow through the fan and a rear end opposite to the front end; and The blades project radially from the hub, each blade including a root connected to the hub and a tip connected to the hub-facing surface of the belt, wherein... At each location along a line extending circumference around the belt, the distance between the fan rotation axis and the belt is constant, wherein the line is positioned on the hub-facing surface of the belt at its rear end. The radial dimension of the band is non-uniform along the line. The belt includes a cylindrical portion, wherein the tip of each blade engages with the cylindrical portion along the corresponding blade tip region. The cylindrical portion includes a first region of the line having a first radial dimension and a second region of the line having a second radial dimension smaller than the first radial dimension. The first region of the line is disposed between corresponding blade tip regions of a pair of adjacent blades, and the second region of the line is radially aligned with the corresponding blade tip regions. Wherein, the first radial dimension is at least 5 percent larger than the second radial dimension and the first radial dimension is at most 20 percent of the blade span, wherein the blade span corresponds to the distance between the root and the tip of the blade.

2. The fan according to claim 1, wherein, The band includes: A cylindrical portion extending parallel to the fan's rotation axis, the cylindrical portion including a rear end; A lip portion, extending at an angle relative to the fan's rotation axis, the surface of the lip portion including a front end; and The middle portion connects one end of the cylindrical portion to one end of the lip portion.

3. The fan according to claim 2, wherein, The first radial dimension is larger than the axial dimension of the lip portion.

4. The fan according to claim 2, wherein, The dimensions of the middle portion are non-uniform along the circumference of the strip, such that the size of the middle portion at a position radially aligned with the first region of the line is larger than the corresponding size of the middle portion at a position radially aligned with the second region of the line.

5. The fan according to claim 2, wherein, The cylindrical portion includes a third region of the line having a tapered radial dimension, the third region of the line providing a transition between the first region and the second region of the line, wherein the circumference of each third region of the line is at least as long as the circumference of its adjacent first region of the line.

6. The fan according to claim 2, wherein, The cylindrical portion includes a third region of the line having a tapered radial dimension, the third region of the line providing a transition between the first region and the second region of the line, wherein the sum of the circumferential dimensions of one of the first regions of the line and each adjacent third region of the line is at least fifty percent of the distance between the tips of adjacent blades.

7. The fan according to claim 1, wherein, The radial dimension of the belt is non-uniform along the line, causing the radial dimension to vary periodically along the circumference of the belt. The radial dimension is largest at the position between adjacent blades and smallest at the position aligned with the blade.

8. The fan according to claim 1, wherein, The band includes: A cylindrical portion extending parallel to the fan's rotation axis, the cylindrical portion including a front end; A lip portion, the lip portion extending at an angle relative to the fan rotation axis, the surface of the lip portion including a rear end; and The middle portion connects one end of the cylindrical portion to one end of the lip portion. And among them, The tip of each blade joins the cylindrical portion along the corresponding blade tip region. The cylindrical portion includes a first region of the line having a first radial dimension and a second region of the line having a second radial dimension. The second radial dimension is smaller than the first radial dimension. The first region of the line is positioned between the corresponding blade tip regions of a pair of adjacent blades, and The second region of the line is radially aligned with the corresponding blade tip region.

9. A fan, the fan comprising: Hub, which is configured to be driven by a motor to rotate about the fan's rotation axis; A belt, the belt being around the axis of rotation and concentric with the hub, the belt including a front end facing the direction of airflow through the fan and a rear end opposite to the front end; and The blades project radially from the hub, each blade including a root connected to the hub and a tip connected to the hub-facing surface of the belt, wherein... At each location along a line extending around the circumference of the belt, the distance between the fan's rotation axis and the belt is constant, wherein the line is positioned on the hub-facing surface of the belt at its rear end. The radial dimension of the band is non-uniform along the line, such that The radial dimension varies periodically along the circumference of the belt, and The radial dimension has a maximum value at the position between adjacent blades and a minimum value at the position aligned with the blade.

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