Axial flow fan blade and air conditioner

Abstract

The application discloses an axial flow fan blade and an air conditioner, and relates to the technical field of air conditioners. The axial flow fan blade comprises a hub and a blade. The blade is fixedly connected to the peripheral surface of the hub, and the blade is provided with a leading edge. A preset tangent line of the leading edge is arranged through a center point of the hub. A reference line is formed between the center point of the hub and the center of gravity of the blade. A first included angle is formed between the preset tangent line and the reference line. The range of the first included angle is 15-25 degrees. Compared with the prior art, the axial flow fan blade provided by the application can effectively improve the strength of the axial flow fan blade, prevent the axial flow fan blade from being deformed or broken under high-speed rotation, and is safe and reliable.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to an axial flow fan blade and an air conditioner. Background Technology

[0002] Currently, in the application of air conditioner outdoor units, airflow is generally generated by driving an axial fan blade through a drive motor to rotate, thereby cooling the condenser and expelling the heat from the condenser to the outside. In recent years, with the continuous rise in international raw material prices, the cost of the air conditioning industry has been greatly affected. As a result, manufacturers have put forward increasingly higher requirements for the cost and performance parameters of fan blades. However, due to current limitations in processing technology and the limitations of the materials themselves, current axial fan blades have strength defects. The most direct impact of these strength defects is that the blades may deform or even break under high-speed operation, resulting in the failure of the entire air conditioner. Summary of the Invention

[0003] The problem solved by this invention is how to effectively improve the strength of axial flow fan blades and prevent them from deforming or breaking under high-speed rotation, ensuring safety and reliability.

[0004] To solve the above problems, the technical solution of the present invention is implemented as follows:

[0005] In a first aspect, the present invention provides an axial flow fan blade, comprising a hub and blades. The blades are fixedly connected to the circumferential surface of the hub. Each blade has a leading edge, and a predetermined tangent of the leading edge passes through the center point of the hub. A reference line is formed between the center point of the hub and the center of gravity of the blade. A first angle is formed between the predetermined tangent and the reference line, with the first angle ranging from 15 to 25 degrees. Compared with the prior art, the axial flow fan blade provided by the present invention, due to the use of a predetermined tangent and a reference line with a first angle, can effectively improve the strength of the axial flow fan blade, preventing deformation or breakage under high-speed rotation, thus ensuring safety and reliability.

[0006] Furthermore, the preset tangent is located at the position where the reference line rotates by the first included angle along the rotation direction of the axial flow blade. The preset tangent deflects from the reference line in the direction of rotation of the axial flow blade, which can effectively reduce the stress on the blade during the rotation of the axial flow blade and prevent the blade from deforming or breaking.

[0007] Furthermore, the first included angle is 19 degrees. A reasonable first included angle can reduce the local stress on the leading edge of the blade, improve the strength performance of the axial flow fan blade, and prevent it from deforming or breaking under high-speed rotation, ensuring safety and reliability.

[0008] Furthermore, a first line segment is formed between the point of tangency of the preset tangent on the leading edge and the intersection of the leading edge and the hub. This first line segment is located on the side of the reference line closest to the preset tangent. This increases the contact area between the inner edge and the hub, thereby improving the connection strength between the blade and the hub, and ultimately improving the overall strength of the axial flow fan blade.

[0009] Furthermore, the first line segment is arc-shaped. This further increases the contact area between the inner edge and the hub, facilitates torque transmission, and prevents sudden stress changes.

[0010] Furthermore, a second line segment is formed between the center point of the hub and the point of tangency of the preset tangent on the leading edge. The length of the first line segment is greater than the difference between the length of the second line segment and the hub radius. This ensures that the contact area between the inner edge and the hub is large enough, thereby improving the connection strength between the blade and the hub.

[0011] Furthermore, the hub includes a base plate, a connecting platform, and an annular sleeve. The connecting platform and the annular sleeve are coaxially arranged and both are fixedly connected to the base plate. The connecting platform is located inside the annular sleeve, and the annular sleeve is fixedly connected to the blades. The drive motor can drive the base plate to rotate through the connecting platform, thereby driving the annular sleeve and blades to rotate, thus realizing the air outlet function.

[0012] Furthermore, the hub also includes a first reinforcing rib, which is fixedly connected to the base plate and connects the connecting platform and the annular sleeve. The first reinforcing rib is used to improve the connection strength between the connecting platform and the annular sleeve, preventing the annular sleeve from deforming during the high-speed rotation of the axial flow fan blades.

[0013] Furthermore, a second angle is formed between the extension direction of the first stiffener and the reference line, with the second angle ranging from 6 to 10 degrees. A reasonable second angle can minimize the maximum stress and strain of the blade, preventing deformation or breakage under high-speed rotation, ensuring safety and reliability.

[0014] Furthermore, the second included angle is 8 degrees. This allows the first reinforcing rib to function effectively, thereby improving the strength, stability, and reliability of the axial flow fan blades.

[0015] Furthermore, the extension direction of the first reinforcing rib is located at the position where the reference line is rotated by a second angle along the rotation direction of the axial flow blade. The deflection of the extension direction of the first reinforcing rib from the reference line toward the rotation direction of the axial flow blade can effectively reduce blade stress.

[0016] Furthermore, there are three blades, arranged in a circular array on the circumference of the hub. The hub can simultaneously drive all three blades to rotate, thereby creating an airflow.

[0017] Secondly, the present invention provides an air conditioner including the aforementioned axial flow fan blade. The axial flow fan blade includes a hub and blades. The blades are fixedly connected to the circumferential surface of the hub. Each blade has a leading edge, and a predetermined tangent of the leading edge passes through the center point of the hub. A reference line is formed between the center point of the hub and the center of gravity of the blade. A first angle is formed between the predetermined tangent and the reference line, with the first angle ranging from 15 to 25 degrees. The air conditioner can effectively improve the strength of the axial flow fan blade, preventing deformation or breakage under high-speed rotation, ensuring safety and reliability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the axial flow fan blade from one perspective according to the first embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the axial flow fan blade described in the first embodiment of the present invention from another perspective;

[0020] Figure 3 This is a schematic diagram of the connection between the hub and the blades in the axial flow fan blade according to the first embodiment of the present invention from one perspective;

[0021] Figure 4 This is a schematic diagram of the connection between the hub and the blades in the axial flow fan blade described in the first embodiment of the present invention from another perspective;

[0022] Figure 5 This is a graph showing the maximum stress and maximum strain of the blade in the axial flow fan blade described in the first embodiment of the present invention as a function of the second included angle at a rotational speed of 3000 rpm.

[0023] Explanation of reference numerals in the attached figures:

[0024] 100-Axial flow fan blade; 110-Hub; 111-Base plate; 112-Connecting platform; 113-Annular sleeve; 114-First reinforcing rib; 115-Second reinforcing rib; 120-Blade; 121-Leading edge; 122-Tail edge; 123-Inner edge; 124-Outer edge. Detailed Implementation

[0025] 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.

[0026] First Embodiment

[0027] Please refer to Figure 1 This invention provides an axial flow fan blade 100 for driving airflow. It effectively improves the strength of the axial flow fan blade 100, preventing deformation or breakage under high-speed rotation, ensuring safety and reliability.

[0028] It should be noted that the axial fan blade 100 is used in the outdoor unit of an air conditioner (not shown). The outdoor unit is installed outdoors and connected to the indoor unit (not shown). The outdoor and indoor units work together to regulate the indoor temperature. The outdoor unit includes a condenser (not shown), a drive motor (not shown), and a casing (not shown). The condenser, drive motor, and axial fan blade 100 are all installed inside the casing. The drive motor is connected to the axial fan blade 100 to rotate it. The position of the axial fan blade 100 corresponds to the position of the condenser, which is used for heat exchange with the refrigerant. The axial fan blade 100 can create negative pressure during rotation, driving airflow to form an outlet airflow. This outlet airflow is used to cool the condenser, removing heat and ensuring its normal operation.

[0029] The axial flow fan blade 100 includes a hub 110 and blades 120. The hub 110 is circular, and the blades 120 are fixedly connected to the circumferential surface of the hub 110. The hub 110 can drive the blades 120 to rotate, thereby driving airflow. The hub 110 is used to connect to a drive motor, and the drive motor can drive the blades 120 to rotate through the hub 110.

[0030] In this embodiment, there are three blades 120 arranged in a circular array on the circumference of the hub 110. The hub 110 can simultaneously drive the three blades 120 to rotate, thereby creating an airflow. However, this is not the only embodiment. In other embodiments, the number of blades 120 can be four or five, and the number of blades 120 is not specifically limited.

[0031] Please refer to the reference. Figure 2 and Figure 3 It should be noted that the blade 120 is provided with a leading edge 121, a trailing edge 122, an inner edge 123, and an outer edge 124. The leading edge 121 and the trailing edge 122 are arranged opposite each other, and the inner edge 123 and the outer edge 124 are arranged opposite each other. The leading edge 121, the outer edge 124, the trailing edge 122, and the inner edge 123 are connected end to end to form the outline shape of the blade 120. Specifically, the inner edge 123 is the side of the blade 120 that connects to the hub 110, the outer edge 124 is the side of the blade 120 away from the hub 110, the leading edge 121 is the side of the blade 120 facing the wind during rotation, and the trailing edge 122 is the side of the blade 120 on the leeward side during rotation.

[0032] It is worth noting that the leading edge 121 is arc-shaped. In the direction extending from the inner edge 123 to the outer edge 124, the leading edge 121 gradually approaches the trailing edge 122 and then gradually moves away from the trailing edge 122. For ease of understanding, the arc segment of the leading edge 121 that gradually approaches the trailing edge 122 in the direction extending from the inner edge 123 to the outer edge 124 is called the first leading edge segment, and the arc segment of the leading edge 121 that gradually moves away from the trailing edge 122 in the direction extending from the inner edge 123 to the outer edge 124 is called the second leading edge segment. The first and second leading edge segments intersect at a connection point. Specifically, the leading edge 121 intersects the inner edge 123 at point A, the connection point is point B, and the leading edge 121 intersects the outer edge 124 at point C. The first leading edge segment is segment AB, and the second leading edge segment is segment BC.

[0033] Furthermore, the hub 110 has a center point (point O), and the blade 120 has a center of gravity (point D). The preset tangent of the leading edge 121 is set through the center point of the hub 110. The line connecting the center point of the hub 110 and the connection point is the preset tangent. A reference line is formed between the center point of the hub 110 and the center of gravity of the blade 120. A first angle is formed between the preset tangent and the reference line, denoted as α. The range of the first angle is 15 to 25 degrees. A reasonable degree of the first angle can reduce the local stress of the leading edge 121 of the blade 120, improve the strength performance of the axial flow fan blade 100, and prevent it from deforming or breaking under high-speed rotation, ensuring safety and reliability. Specifically, the preset tangent is located at the position where the reference line rotates at the first included angle along the rotation direction of the axial flow fan blade 100. The preset tangent deflects from the reference line toward the rotation direction of the axial flow fan blade 100, which can effectively reduce the stress on the blade 120 during the rotation of the axial flow fan blade 100 and prevent the blade 120 from deforming or breaking.

[0034] In this embodiment, the first included angle is 19 degrees, but it is not limited to this. In other embodiments, the first included angle can be 15 degrees or 25 degrees. The size of the first included angle is not specifically limited.

[0035] It should be noted that the first line segment is formed between the point of tangency of the preset tangent on the leading edge 121 and the intersection of the leading edge 121 and the hub 110. This first line segment is the first leading edge segment, located on the side of the reference line closest to the preset tangent. This increases the contact area between the inner edge 123 and the hub 110, thereby improving the connection strength between the blade 120 and the hub 110, and ultimately enhancing the overall strength of the axial flow fan blade 100.

[0036] In this embodiment, the first line segment is arc-shaped and protrudes towards the hub 110 to further increase the contact area between the inner edge 123 and the hub 110, and facilitate torque transmission and prevent sudden stress changes. Specifically, the central angle of the arc formed by the first line segment is denoted as b, and the range of the central angle of the arc formed by the first line segment is 30 degrees to 50 degrees. A reasonable central angle of the arc formed by the first line segment can maximize the contact area between the inner edge 123 and the hub 110 while preventing excessive local glue thickness between the inner edge 123 and the hub 110, thereby effectively improving the strength of the axial flow fan blade 100.

[0037] In this embodiment, the central angle of the arc formed by the first line segment is 40 degrees, but it is not limited to this. In other embodiments, the central angle of the arc formed by the first line segment can be 30 degrees or 50 degrees. The size of the central angle of the arc formed by the first line segment is not specifically limited.

[0038] In this embodiment, a second line segment is formed between the center point of the hub 110 and the tangent point of the preset tangent on the leading edge 121. The second line segment is segment OB. The length of the first line segment is greater than the difference between the length of the second line segment and the radius of the hub 110, so as to ensure that the contact area between the inner edge 123 and the hub 110 is large enough and to improve the connection strength between the blade 120 and the hub 110.

[0039] It is worth noting that during the rotation of the axial flow fan blade 100, the blade 120 is mainly subjected to two forces: centrifugal force and aerodynamic loads caused by airflow. The centrifugal force causes the blade 120 to stretch or bend, while the aerodynamic loads cause the blade 120 to bend. The centrifugal force and the stress it causes are zero at the blade tip of the blade 120 and gradually increase towards the blade root, reaching their maximum value at the blade root. Since the bending stress generated by the aerodynamic load is negligible compared to the stress generated by the centrifugal force, the stress at the blade root of the blade 120 mainly comes from the tensile stress and bending stress caused by the centrifugal force.

[0040] Therefore, this invention has conducted extensive research and experiments on the connection form between the blade 120 and the hub 110 at the leading edge 121. First, it was determined that the strength of the axial flow fan blade 100 under high-speed rotation is highly correlated with the blade root leading edge structure (the connection between the leading edge 121 and the inner edge 123). Then, finite element analysis was performed on the blade root leading edge structure of the axial flow fan blade 100 to analyze the stress concentration of the blade 120 from a mechanistic perspective and to explore effective optimization methods to reduce stress concentration. Finally, it was concluded that forming an angle of 15 to 25 degrees between the preset tangent and the reference line can effectively improve the strength of the blade root leading edge structure, thereby improving the overall strength of the axial flow fan blade 100.

[0041] Please refer to the reference. Figure 2 and Figure 4The hub 110 includes a base plate 111, a connecting platform 112, an annular sleeve 113, a first reinforcing rib 114, and a second reinforcing rib 115. The connecting platform 112 and the annular sleeve 113 are coaxially arranged and both are fixedly connected to the base plate 111. The connecting platform 112 is disposed inside the annular sleeve 113 and is used to connect to the drive motor. The annular sleeve 113 is fixedly connected to the blades 120. The drive motor can drive the base plate 111 to rotate through the connecting platform 112, thereby driving the annular sleeve 113 and the blades 120 to rotate, thus realizing the air outlet function.

[0042] In this embodiment, the first reinforcing rib 114 is fixedly connected to the base plate 111 and connects the connecting platform 112 and the annular sleeve 113. The first reinforcing rib 114 is used to improve the connection strength between the connecting platform 112 and the annular sleeve 113 and prevent the annular sleeve 113 from deforming during the high-speed rotation of the axial flow fan blade 100. The second reinforcing rib 115 is fixedly connected to the base plate 111 and connects the connecting platform 112 and the annular sleeve 113. The second reinforcing rib 115 is also used to improve the connection strength between the connecting platform 112 and the annular sleeve 113, so as to further prevent the annular sleeve 113 from deforming during the high-speed rotation of the axial flow fan blade 100.

[0043] Specifically, there are three first reinforcing ribs 114 and three second reinforcing ribs 115. The position of each first reinforcing rib 114 and one second reinforcing rib 115 corresponds to the position of one blade 120. The first reinforcing ribs 114 and the second reinforcing ribs 115 can improve the stress distribution of the corresponding blade 120 while preventing the annular sleeve 113 from deforming, thus enhancing the function of the first reinforcing ribs 114 and the second reinforcing ribs 115.

[0044] In this embodiment, the first reinforcing rib 114 is disposed on the side of the reference line near the leading edge 121. The extension direction of the first reinforcing rib 114 passes through the center point of the hub 110, that is, the extension direction of the first reinforcing rib 114 is obtained by deflecting the reference line towards the direction of rotation of the axial flow blade 100. Compared with the prior art where the extension direction of the first reinforcing rib 114 is the direction of the line connecting the center point of the hub 110 and the center of gravity of the blade 120, this embodiment simulates the deformation of the axial flow blade 100 under high-speed rotation (3000 rpm) by changing the circumferential distribution position of the first reinforcing rib 114, and concludes that the deviation of the extension direction of the first reinforcing rib 114 from the reference line can effectively reduce the stress on the blade 120.

[0045] It should be noted that the extension direction of the first reinforcing rib 114 forms a second angle with the reference line, denoted as θ. The range of the second angle is 6 to 10 degrees. A reasonable degree of the second angle can minimize the maximum stress and maximum strain of the blade 120, preventing deformation or breakage under high-speed rotation, ensuring safety and reliability. Specifically, the extension direction of the first reinforcing rib 114 is located at the position of the second angle along the rotation direction of the axial flow fan blade 100 from the reference line.

[0046] In this embodiment, the second included angle is 8 degrees, but it is not limited to this. In other embodiments, the second included angle can be 6 degrees or 10 degrees. The size of the second included angle is not specifically limited.

[0047] Please refer to Figure 5 It is worth noting that by studying the effect of changing the degree of the second included angle on the maximum stress and maximum strain of blade 120, a curve was obtained showing the variation of the maximum stress and maximum strain of blade 120 with the second included angle at a rotational speed of 3000 rpm. Here, a second included angle of 0 represents the existing technical solution. From this curve, it can be seen that the maximum stress and maximum strain of blade 120 vary greatly with the location of the first reinforcing rib, and both are non-monotonic functions. As the second included angle increases, the maximum stress and maximum strain fluctuate, and there exists an optimal second included angle that minimizes both the maximum stress and maximum strain of blade 120.

[0048] Specifically, when the second included angle is 8 degrees, the maximum stress and maximum strain of blade 120 are minimized, with a maximum stress of 100.3 MPa. Compared to existing technologies, this represents a 19.1% reduction in maximum stress and a 3.0% reduction in maximum strain. When the second included angle is 11 degrees, the maximum strain of blade 120 reaches its minimum at 76.9 mm, a 3.9% decrease compared to existing technologies. However, the maximum stress experienced by blade 120 at this point is essentially the same as in existing technologies. Considering all factors, a second included angle of 8 degrees is the optimal solution, as it improves stress distribution without increasing blade 120 deformation.

[0049] Furthermore, when the second included angle is 8 degrees, the maximum stress on the blade 120 is still located at the leading edge structure of the blade root. The stress distribution on both sides of the first reinforcing rib 114 is relatively symmetrical, indicating that the first reinforcing rib 114 is mainly subjected to radial tensile force. At this time, the function of the first reinforcing rib 114 can be well exerted, which can effectively improve the strength of the axial flow fan blade 100 and make it stable and reliable.

[0050] The axial flow fan blade 100 of this embodiment has blades 120 fixedly connected to the circumferential surface of a hub 110. Each blade 120 has a leading edge 121, with a pre-defined tangent line passing through the center of the hub 110. A reference line is formed between the center of the hub 110 and the center of gravity of the blade 120. A first angle is formed between the pre-defined tangent line and the reference line, with the first angle ranging from 15 to 25 degrees. Compared with the prior art, the axial flow fan blade 100 provided by this invention, due to the use of a pre-defined tangent line and a reference line forming a first angle, can effectively improve the strength of the axial flow fan blade 100, preventing deformation or breakage under high-speed rotation, thus ensuring safety and reliability.

[0051] Second Embodiment

[0052] This invention provides an air conditioner (not shown) for regulating indoor temperature. The air conditioner includes an outdoor unit and an indoor unit, with the outdoor unit comprising a casing, a condenser, a drive motor, and an axial fan blade 100. The basic structure, principle, and technical effects of the axial fan blade 100 are the same as in the first embodiment. For brevity, any parts not mentioned in this embodiment can be referred to the corresponding content in the first embodiment.

[0053] In this embodiment, the outdoor unit of the air conditioner is installed outdoors and connected to the indoor unit. The outdoor and indoor units work together to regulate the indoor temperature. The condenser, drive motor, and axial fan 100 are all installed inside the casing. The drive motor is connected to the axial fan 100, and the position of the axial fan 100 corresponds to the position of the condenser. The axial fan 100 can generate negative pressure during rotation, driving airflow to form an exhaust airflow. This exhaust airflow can cool the condenser, removing heat and ensuring its normal operation, thereby enabling the indoor unit to heat or cool the room.

[0054] The beneficial effects of the air conditioner described in this embodiment are the same as those of the first embodiment, and will not be repeated here.

[0055] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An axial flow fan blade, characterized in that, The device includes a hub (110) and a blade (120). The blade (120) is fixedly connected to the circumferential surface of the hub (110). The blade (120) is provided with a leading edge (121). A preset tangent of the leading edge (121) passes through the center point of the hub (110). A reference line is formed between the center point of the hub (110) and the center of gravity of the blade (120). A first angle is formed between the preset tangent and the reference line. The first angle is in the range of 15 to 25 degrees. The preset tangent is located at the position of the first included angle when the reference line rotates along the rotation direction of the axial flow fan blade; The hub (110) includes a base plate (111), a connecting platform (112), and an annular sleeve (113). The connecting platform (112) and the annular sleeve (113) are coaxially arranged and fixedly connected to the base plate (111). The connecting platform (112) is disposed inside the annular sleeve (113), and the annular sleeve (113) is fixedly connected to the blade (120).

2. The axial flow fan blade according to claim 1, characterized in that, The first included angle is 19 degrees.

3. The axial flow fan blade according to claim 1, characterized in that, The preset tangent forms a first line segment between the point of tangency of the leading edge (121) and the intersection of the leading edge (121) and the hub (110), and the first line segment is located on the side of the reference line close to the preset tangent.

4. The axial flow fan blade according to claim 3, characterized in that, The first line segment is arc-shaped.

5. The axial flow fan blade according to claim 3, characterized in that, The center point of the hub (110) and the point of tangency of the preset tangent on the leading edge (121) form a second line segment, the length of the first line segment being greater than the difference between the length of the second line segment and the radius of the hub (110).

6. The axial flow fan blade according to claim 1, characterized in that, The hub (110) also includes a first reinforcing rib (114), which is fixedly connected to the base plate (111) and connected between the connecting platform (112) and the annular sleeve (113).

7. The axial flow fan blade according to claim 6, characterized in that, The extension direction of the first reinforcing rib (114) forms a second angle with the reference line, and the range of the second angle is 6 degrees to 10 degrees.

8. The axial flow fan blade according to claim 7, characterized in that, The second included angle is 8 degrees.

9. The axial flow fan blade according to claim 7, characterized in that, The extension direction of the first reinforcing rib (114) is located at the position of the second included angle when the reference line rotates along the rotation direction of the axial flow fan blade.

10. The axial flow fan blade according to claim 1, characterized in that, The number of blades (120) is three, and the three blades (120) are arranged in a ring array on the circumferential surface of the hub (110).

11. An air conditioner, characterized in that, Including the axial flow fan blades as described in any one of claims 1 to 10.

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