Detection method of axial flow fan blade

Abstract

The invention discloses an axial-flow fan blade detection method, which comprises the steps that an axial-flow fan blade is installed on a rotating tool, and the axial-flow fan blade comprises N blades; the rotating tool drives the axial flow fan blades to rotate, each blade passes through the detection position of the visual detection device, and the visual detection device obtains the height position of the highest point of each blade and obtains the height position of the lowest point of each blade; the height Hn of each blade is calculated, and the high-point axis jerk value of the highest point of the N blades and the low-point axis jerk value of the lowest point of the N blades are calculated. The visual detection device automatically obtains the height position of the highest point and the height position of the lowest point of each blade, and then calculates the height of each blade and the high-point shaft jerk value and the low-point shaft jerk value of the multiple blades, so that the height and the shaft jerk value of the axial flow fan blade can be automatically detected, manual detection can be replaced, and the detection efficiency is improved. And the labor cost and human errors are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of axial flow fan blade detection, and in particular to a detection method for axial flow fan blades. Background Art

[0002] Axial flow blades are commonly used components of axial flow fans. Before the axial flow blades are produced and shipped, it is necessary to test whether the height of the blades and the axial runout of multiple blades are within the standard range. The current detection method is to manually rotate the axial flow blades so that the highest point of each blade passes through the high point gap between the high point calipers, and the lowest point passes through the low point gap between the low point calipers. If the highest point and the lowest point of the blade can pass through the high point gap and the low point gap respectively, it means that the height and axial runout of the axial flow blade are within the standard range. However, this detection method requires manual rotation of the blades and detection, which has high labor costs and is prone to human errors. Those skilled in the art hope to have an automatic detection method that can replace manual detection. Summary of the Invention

[0003] The main purpose of the present invention is to propose a method for detecting axial flow fan blades, aiming to solve the technical problems in the prior art of manually detecting the height and shaft runout of axial flow fan blades, which has high labor costs and is prone to human errors.

[0004] To achieve the above object, the present invention provides a method for detecting an axial flow fan blade, comprising: S1: Installing an axial flow fan blade on a rotating fixture, wherein a rotation axis of the rotating fixture is coaxially arranged with an axis of the axial flow fan blade, and the axial flow fan blade includes N blades; S2: The rotating fixture drives the axial flow fan blades to rotate, so that each blade passes through the detection position of the visual detection device, and the visual detection device obtains the height position of the highest point of each blade and the height position of the lowest point of each blade; S3: Calculate the height H of each blade according to the height position of the highest point and the height position of the lowest point of each blade. n , where n=1, 2...N, and the high-point axial runout of the highest points of the N blades and the low-point axial runout of the lowest points of the N blades are calculated.

[0005] During inspection, the axial fan blades are installed and fixed on a rotating tooling, which can drive the axial fan blades to rotate. While the axial fan blades rotate, multiple blades of the axial fan blades pass through the inspection positions of the visual inspection device respectively. The visual inspection device automatically obtains the height position of the highest point and the height position of the lowest point of each blade, and then calculates the height of each blade and the axial runout of multiple blades at high points and low points, thereby automatically completing the inspection of the height and axial runout of the axial fan blades, which can replace manual inspection and reduce labor costs and human errors.

[0006] Preferably, in step S2, the step of obtaining the height position of the highest point and the height position of the lowest point of the blade includes: The rotating fixture drives the axial flow fan blade to rotate until the highest point of the target blade reaches the detection position of the visual detection device. The visual detection device obtains the radial visual image of the highest point of the target blade. The image processing system calculates the distance between the highest point of the blade and the high-level reference line S1 in the radial visual image of the highest point and converts it into the actual high-level spacing h n1 , wherein the high position reference line S1 is located above the highest point of the blade, and the actual high position spacing h n1 is the height position of the highest point of the target blade; The rotating fixture drives the axial flow fan blade to rotate until the lowest point of the target blade reaches the detection position of the visual detection device. The visual detection device obtains the radial visual image of the lowest point of the target blade. The image processing system calculates the distance between the lowest point of the blade and the low-level reference line S2 in the radial visual image of the lowest point and converts it into the actual low-level spacing h n2 , wherein the low position reference line S2 is located below the lowest point of the blade, and the actual low position spacing h n2 is the height position of the lowest point of the target blade; When the N blades have passed the detection position of the visual detection device, the actual height spacing h of the N blades is obtained. 11 、h 21 ...h N1 , and get the actual low-level spacing h of the N blades 12 、h 22 ...h N2 .

[0007] The axial flow blades rotate to the highest point and lowest point of the target blade respectively. The visual detection device obtains the radial visual image of the highest point and the radial visual image of the lowest point of the target blade respectively. The image processing system calculates the distance between the highest point of the blade and the high-position reference line S1 and the distance between the lowest point of the blade and the low-position reference line S2, which can be converted into the actual high-position spacing h of each blade. n1 and the actual low bit spacing hn2 .

[0008] Preferably, the steps of determining that the rotating fixture drives the axial flow fan blade to rotate to the highest point of the target blade to reach the detection position of the visual detection device, and determining that the rotating fixture drives the axial flow fan blade to rotate to the lowest point of the target blade to reach the detection position of the visual detection device include: The rotating tool is based on the preset highest point angle value α of the target blade. n Drive the axial fan blade to rotate to the highest point of the target blade and the preset lowest point angle value β of the target blade n Drive the axial flow fan blade to rotate to the lowest point of the target blade.

[0009] Preset highest point angle value α n and the preset lowest point angle β n The uniform rotation angle value of the batch axial flow fan blades is that each axial flow fan blade rotates to the corresponding preset highest point angle value α of each blade. n and the preset lowest point angle β n The determined rotation angle, which serves as the highest point and the lowest point of the corresponding blade, can speed up the rotation speed and shorten the image calculation time, and can also more clearly understand the deviation of the axial flow fan blade.

[0010] Preferably, the preset highest point angle value α of the target blade is obtained n and the preset lowest point angle value β of the target blade n The steps include: Before testing batches of axial flow fan blades of the same model, first install a standard axial flow fan blade of the same model on the rotating fixture; Set the detection angle origin of the rotating fixture and axial flow fan blades; Rotate the rotating tooling and the axial flow fan blade until the target blade passes the detection position of the visual detection device and detect the rotation angle relative to the detection angle origin, determine when the highest point of the target blade is displayed at the highest height on the visual image of the visual detection device, stop the rotation, and obtain the current rotation angle of the rotating tooling and the axial flow fan blade as the preset highest point angle value α of the target blade n And save it for subsequent batch testing; Rotate the rotating tooling and the axial flow fan blade until the target blade passes the detection position of the visual detection device and detect the rotation angle relative to the detection angle origin, determine when the lowest point of the target blade is displayed at the lowest height on the visual image of the visual detection device, stop the rotation, and obtain the current rotation angle of the rotating tooling and the axial flow fan blade as the preset lowest point angle value β of the target blade n And save it for subsequent batch testing.

[0011] Preferably, the step of obtaining the highest point of the blade in the highest point radial visual image comprises: The image processing system performs boundary fitting on the upper edge of the blade in the acquired radial visual image of the highest point to obtain an upper edge fitting line, wherein the highest point of the upper edge fitting line is the highest point of the blade; The step of obtaining the lowest point of the blade in the lowest point radial visual image comprises: The image processing system performs boundary fitting on the lower edge of the blade in the acquired radial visual image of the lowest point to obtain a lower edge fitting line, wherein the lowest point of the lower edge fitting line is the lowest point of the blade.

[0012] Preferably, the method for obtaining the high reference line S1 includes: A high-position reference object is provided on the upper side of the blade, and a straight line formed by the lower edge of the high-position reference object in the radial visual image of the highest point is the high-position reference line S1; The method for obtaining the low reference line S2 includes: A fixed low-position reference object is provided on the lower side of the blade, and a straight line formed by the lower edge of the low-position reference object in the radial visual image of the lowest point is the low-position reference line S2.

[0013] By using fixed high-position reference objects and low-position reference objects as reference comparison, the position change between the visual detection device and the axial flow fan blade can be corrected and adapted.

[0014] Preferably, the actual high position distance h is calculated n1 and the actual low bit spacing h n2 The steps include: The image processing system obtains the number of pixels P between the highest point of the blade and the high reference line S1 n1 , then the actual high position spacing h n1 =P n1 *T / P0; The image processing system obtains the number of pixels P between the lowest point of the leaf and the low reference line S2 n2 , then the actual low-level spacing h n2 =P n2 *T / P0; Among them, the visual detection device obtains a visual image of the thickness of the actual size reference object, and the image processing system obtains the number of pixels of the thickness of the actual size reference object in the visual image as P0; T is the actual size value of the thickness of the actual size reference object set.

[0015] The image obtained by the visual inspection device needs to convert the number of pixels into actual size. Therefore, the actual size value T and the number of pixels P0 of the actual size reference object are first converted to obtain the actual proportional relationship between the actual size and the number of pixels, which can improve the accuracy of the conversion and thus improve the accuracy of the inspection.

[0016] Preferably, in step S3, the height H of each blade is calculated n The methods include: Obtain the distance H0 between the upper reference line S1 and the lower reference line S2, then H n =H0-h n1 -h n2 .

[0017] Preferably, the method for calculating the highest point axial runout of the N highest points of the blades in step S3 is: High point axis runout = max (h n1 )-min(h n1 ), where max(h n1 ) is the actual height spacing h of the N blades 11 、h 21 ...h N1 The maximum value, min (h n1 ) is the actual height spacing h of the N blades 11 、h 21 ...h N1 The minimum value of The method for calculating the lowest point axial runout of the N lowest points of the blades in step S3 is: Low point axis runout = max (h n2 )-min(h n2 ), where max(h n2 ) is the actual low-level spacing h of the N blades 12 、h 22 ...h N2 The maximum value, min (h n2 ) is the actual low-level spacing h of the N blades 12 、h 22 ...h N2 The minimum value of .

[0018] Preferably, the visual detection device includes a high-position visual detection camera and a low-position visual detection camera, the high-position visual detection camera is arranged on the upper side of the low-position visual detection camera, the high-position visual detection camera is set to match the upper height of the axial flow fan blade, and the low-position visual detection camera is set to match the lower height of the axial flow fan blade, the high-position visual detection camera is used to obtain the height position of the highest point of the blade, and the low-position visual detection camera is used to obtain the height position of the lowest point of the blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0020] Figure 1 This is a schematic diagram of the front structure of the detection equipment used in the present invention; Figure 2 It is a schematic diagram of the size relationship between the blade, the high-position reference object and the low-position reference object of the present invention; Figure 3 This is a schematic diagram of the top view of the detection equipment used in the present invention; Figure 4 It is a schematic diagram of the preset highest point angle values ​​and the preset lowest point angle values ​​of multiple blades of the axial flow fan blade of the present invention.

[0021] In the attached figure: 1-axial fan blade, 11-blade, 2-rotating tooling, 21-driving motor, 3-high-position reference object, 4-low-position reference object, 5-high-position visual inspection camera, 6-low-position visual inspection camera, 7-backlight source.

[0022] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0024] It should be noted that if the embodiments of the present invention involve directional indications, such as up, down, left, right, front, and back, the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0025] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0026] like Figures 1 to 4 As shown, a method for detecting an axial flow fan blade includes: S1: Install the axial flow fan blade 1 on the rotating fixture 2, wherein the rotation axis of the rotating fixture 2 is coaxial with the axis of the axial flow fan blade 1. The rotating fixture 2 is driven by the driving motor 21. The axial flow fan blade 1 includes N blades 11. The middle portion of the axial flow fan blade 1 is installed on the rotating fixture 2. S2: The rotating tool 2 drives the axial flow fan blade 1 to rotate, so that each blade 11 passes through the detection position of the visual detection device respectively. A backlight source 7 is provided on the opposite side of the visual detection device. The blade 11 passes between the visual detection device and the backlight source 7. The visual detection device obtains the height position of the highest point of each blade 11 and the height position of the lowest point of each blade 11; S3: Calculate the height H of each blade 11 based on the height position of the highest point and the height position of the lowest point of each blade 11 n , where n=1, 2...N, and the high-point axial runout of the highest points of the N blades 11 and the low-point axial runout of the lowest points of the N blades 11 are calculated.

[0027] During inspection, the axial flow fan blade 1 is installed and fixed on the rotating tooling 2. The rotating tooling 2 can drive the axial flow fan blade 1 to rotate. While the axial flow fan blade 1 rotates, multiple blades 11 of the axial flow fan blade 1 respectively pass through the inspection position of the visual inspection device. The visual inspection device automatically obtains the height position of the highest point and the height position of the lowest point of each blade 11, and then calculates the height of each blade 11 and the high point axial runout and low point axial runout of multiple blades 11, thereby automatically completing the inspection of the height and axial runout of the blades 11 of the axial flow fan blade 1, which can replace manual inspection and reduce labor costs and human errors.

[0028] In some specific embodiments, in step S2, the step of obtaining the height position of the highest point and the height position of the lowest point of a blade 11 (taking the blade 11 as the target blade) includes: The rotating fixture 2 drives the axial flow fan blade 1 to rotate until the highest point of the target blade reaches the detection position of the visual detection device. The visual detection device obtains the radial visual image of the highest point of the target blade. The image processing system calculates the distance between the highest point of the blade and the high-position reference line S1 in the radial visual image of the highest point and converts it into the actual high-position spacing h n1 , where the high reference line S1 is located on the upper side of the highest point of the blade, and the actual high distance h n1 is the height position of the highest point of the target blade; The rotating fixture 2 drives the axial flow fan blade 1 to rotate to the lowest point of the target blade and reaches the detection position of the visual detection device. The visual detection device obtains the radial visual image of the lowest point of the target blade. The image processing system calculates the distance between the lowest point of the blade and the low-position reference line S2 in the radial visual image of the lowest point and converts it into the actual low-position spacing h n2 , where the low position reference line S2 is located on the lower side of the lowest point of the blade, and the actual low position spacing h n2 is the height position of the lowest point of the target blade; When all N blades 11 pass through the detection position of the visual detection device, the actual height spacing h of the N blades 11 is obtained. 11 、h 21 ...h N1 , and the actual low-level spacing h of the N blades 11 is obtained 12 、h 22 ...h N2 .

[0029] The axial flow fan blade 1 rotates to the highest point and the lowest point of the target blade respectively. The visual detection device obtains the radial visual image of the highest point and the radial visual image of the lowest point of the target blade respectively. The image processing system calculates the distance between the highest point of the blade and the high-position reference line S1 and the distance between the lowest point of the blade and the low-position reference line S2, which can be converted into the actual high-position spacing h of each blade 11. n1 and the actual low bit spacing h n2 .

[0030] In some specific embodiments, the steps of determining that the rotating tool 2 drives the axial flow fan blade 1 to rotate to the highest point of the target blade to reach the detection position of the visual detection device, and determining that the rotating tool 2 drives the axial flow fan blade 1 to rotate to the lowest point of the target blade to reach the detection position of the visual detection device include: The rotating tool 2 is adjusted according to the preset highest point angle value α of the target blade. nDrive the axial fan blade 1 to rotate to the highest point of the target blade and the preset lowest point angle value β of the target blade n Drive the axial flow fan blade 1 to rotate to the lowest point of the target blade.

[0031] Preset highest point angle value α n and the preset lowest point angle β n The angle value of rotation of the axial flow fan blades 1 is unified in batches. Each axial flow fan blade 1 rotates to the corresponding preset highest point angle value α of each blade 11. n and the preset lowest point angle β n The determined rotation angles corresponding to the highest and lowest points of the blade 11 can increase the rotation speed and shorten the image calculation time, and can also more clearly understand the deviation of the axial flow blade 1 .

[0032] In some specific embodiments, the preset highest point angle value α of the target blade is obtained. n and the preset lowest point angle β of the target blade n The steps include: Before testing batches of axial flow fan blades 1 of the same model, first install a standard axial flow fan blade 1 of the same model on the rotating fixture 2; Set the detection angle origin of the rotating fixture 2 and the axial flow fan blade 1. In subsequent tests, the axial flow fan blade 1 is installed on the rotating fixture 2 at the same angle. When starting the test, first rotate it until the detection angle origin is zero, and then start the rotation test; Rotate the rotating tooling 2 and the axial flow fan blade 1 until the target blade passes the detection position of the visual detection device and detect the rotation angle relative to the detection angle origin. Specifically, the rotation angle can be detected by an angle detection sensor or the drive motor 21 is a servo motor. It is manually determined that the rotation is stopped when the highest point of the target blade is at the highest display height on the visual image of the visual detection device. The current rotation angle of the rotating tooling 2 and the axial flow fan blade 1 is obtained as the preset highest point angle value α of the target blade. n And save it for subsequent batch testing; Rotate the rotating fixture 2 and the axial flow fan blade 1 until the target blade passes the detection position of the visual detection device and detect the rotation angle relative to the detection angle origin. Manually judge that the rotation stops when the lowest point of the target blade is at the lowest height displayed on the visual image of the visual detection device. The current rotation angle of the rotating fixture 2 and the axial flow fan blade 1 is obtained as the preset lowest point angle value β of the target blade. n And save it for subsequent batch testing.

[0033] When the N blades 11 are preset, the preset highest point angle values ​​α1, α2, ..., α of the N blades 11 can be obtained. N , and the preset lowest point angle values ​​β1, β2...βN , refer to Figure 4 .

[0034] In some specific embodiments, the step of obtaining the highest point of the blade in the highest point radial visual image includes: The image processing system performs boundary fitting on the upper edge of the leaf in the acquired highest point radial visual image to obtain an upper edge fitting line. The boundary fitting can be captured by the ROI frame, and the highest point of the upper edge fitting line is the highest point of the leaf; The steps of obtaining the lowest point of the blade in the lowest radial visual image include: The image processing system performs boundary fitting on the lower edge of the blade in the acquired lowest point radial visual image to obtain a lower edge fitting line, and the lowest point of the lower edge fitting line is the lowest point of the blade.

[0035] In some specific embodiments, the method for obtaining the high reference line S1 includes: A high-position reference object 3 is provided on the upper side of the blade 11, and a straight line formed by the lower edge of the high-position reference object 3 in the highest point radial visual image is a high-position reference line S1; The method for obtaining the low reference line S2 includes: A fixed low-position reference object 4 is provided on the lower side of the blade 11 , and a straight line formed by the lower edge of the low-position reference object 4 in the lowest point radial visual image is a low-position reference line S2 .

[0036] By using the fixed high-position reference object 3 and the low-position reference object 4 as reference for comparison, the position change between the visual detection device and the axial flow blade 1 can be corrected and adapted.

[0037] Specifically, the high-position reference object 3 and the low-position reference object 4 can be different objects set on the upper and lower sides, or the same object can be moved up and down to different positions. In other embodiments, the high-position reference line S1 and the low-position reference line S2 can also be virtual reference lines pre-set in the image processing system. The height of the high-position reference line S1 can be known based on the relationship between the position of the virtual reference line in the highest point radial visual image and the height position of the visual detection device; the height of the low-position reference line S2 can be known based on the relationship between the position of the virtual reference line in the lowest point radial visual image and the height position of the visual detection device, thereby calculating the height of the blade.

[0038] In some embodiments, the actual upper bit spacing h is calculated n1 and the actual low bit spacing h n2 The steps include: The image processing system obtains the number of pixels P between the highest point of the leaf and the high reference line S1 n1 , then the actual high position spacing h n1 =P n1 *T / P0; The image processing system obtains the number of pixels P between the lowest point of the leaf and the low reference line S2 n2 , then the actual low-level spacing h n2 =P n2 *T / P0; Among them, the visual detection device obtains a visual image of the thickness of the actual size reference object, and the image processing system obtains the number of pixels of the thickness of the actual size reference object in the visual image as P0; T is the actual size value of the thickness of the set actual size reference object, and T can be set by manual input.

[0039] The image captured by the visual inspection device needs to have its pixel count converted to actual size. Therefore, the actual size value T and pixel count P0 of the actual size reference object are first converted to obtain the actual proportional relationship between the actual size and pixel count. This improves the accuracy of the conversion and, therefore, the accuracy of the inspection. Preferably, the upper reference object 3 and / or the lower reference object 4 can serve as the actual size reference object.

[0040] In some specific embodiments, the height H of each blade 11 is calculated in step S3. n The methods include: Obtain the distance H0 between the high reference line S1 and the low reference line S2. The distance H0 can be set manually, or the high reference object 3 and the low reference object 4 are the same reference object, which moves to the high and low positions by moving up and down. The distance H0 can be obtained by subtracting the thickness of the reference object from the moving distance of the reference object. Then H n =H0-h n1 -h n2 .

[0041] In some specific embodiments, the method for calculating the highest point axial runout of the highest points of the N blades 11 in step S3 is: High point axis runout = max (h n1 )-min(h n1 ), where max(h n1 ) is the actual height spacing h of the N blades 11 11 、h 21 ...h N1 The maximum value, min (h n1 ) is the actual height spacing h of the N blades 11 11 、h 21 ...h N1 The minimum value of The method for calculating the lowest point axial runout of the N blades 11 in step S3 is: Low point axis runout = max (h n2 )-min(h n2), where max(h n2 ) is the actual low-level spacing h of the N blades 11 12 、h 22 ...h N2 The maximum value, min (h n2 ) is the actual low-level spacing h of the N blades 11 12 、h 22 ...h N2 The minimum value of .

[0042] In some specific embodiments, the visual inspection device includes a high-position visual inspection camera 5 and a low-position visual inspection camera 6. The high-position visual inspection camera 5 is arranged above the low-position visual inspection camera 6. The high-position visual inspection camera 5 is arranged to match the height of the upper side of the axial flow fan blade 1, and the low-position visual inspection camera 6 is arranged to match the height of the lower side of the axial flow fan blade 1. The high-position visual inspection camera 5 is used to obtain the height position of the highest point of the blade 11, and the low-position visual inspection camera 6 is used to obtain the height position of the lowest point of the blade 11. In other embodiments, the high-position visual inspection camera 5 and the low-position visual inspection camera 6 can be the same camera, and the camera detects the upper and lower sides of the blade 11 by moving up and down.

[0043] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for detecting an axial flow fan blade, characterized in that: The following steps are involved: S1: Mounting an axial flow fan blade (1) on a rotating fixture (2), wherein a rotation axis of the rotating fixture (2) is coaxially arranged with an axis of the axial flow fan blade (1), and the axial flow fan blade (1) includes N blades (11); S2: the rotating tool (2) drives the axial flow fan blade (1) to rotate, so that each blade (11) passes through the detection position of the visual detection device respectively, and the visual detection device obtains the height position of the highest point of each blade (11) and the height position of the lowest point of each blade (11); S3: Calculate the height H of each blade (11) based on the height position of the highest point and the height position of the lowest point of each blade (11). n , where n=1, 2...N, and the high-point axial runout of the highest points of the N blades (11) and the low-point axial runout of the lowest points of the N blades (11) are calculated.

2. The method for detecting an axial flow fan blade according to claim 1, wherein: In step S2, the step of obtaining the height position of the highest point and the height position of the lowest point of the blade (11) comprises: The rotating fixture (2) drives the axial flow fan blade (1) to rotate until the highest point of the target blade reaches the detection position of the visual detection device. The visual detection device obtains a radial visual image of the highest point of the target blade. The image processing system calculates the distance between the highest point of the blade and the high-position reference line S1 in the radial visual image of the highest point and converts it into an actual high-position spacing h n1 , wherein the high position reference line S1 is located above the highest point of the blade, and the actual high position spacing h n1 is the height position of the highest point of the target blade; The rotating fixture (2) drives the axial flow fan blade (1) to rotate until the lowest point of the target blade reaches the detection position of the visual detection device. The visual detection device obtains the radial visual image of the lowest point of the target blade. The image processing system calculates the distance between the lowest point of the blade and the low-position reference line S2 in the radial visual image of the lowest point and converts it into the actual low-position spacing h n2 , wherein the low position reference line S2 is located below the lowest point of the blade, and the actual low position spacing h n2 is the height position of the lowest point of the target blade; When the N blades (11) have all passed the detection position of the visual detection device, the actual height spacing h of the N blades (11) is obtained. 11 、h 21 ...h N1 , and obtain the actual low-level spacing h of N blades (11) 12 、h 22 ...h N2 .

3. The method for detecting an axial flow fan blade according to claim 2, wherein: The steps of determining that the rotating tool (2) drives the axial flow fan blade (1) to rotate to the highest point of the target blade and reaches the detection position of the visual detection device, and determining that the rotating tool (2) drives the axial flow fan blade (1) to rotate to the lowest point of the target blade and reaches the detection position of the visual detection device include: The rotating tool (2) is configured to adjust the maximum angle value α of the target blade according to the preset maximum angle value α. n Drive the axial flow fan blade (1) to rotate to the highest point of the target blade and the preset lowest point angle value β of the target blade n The axial flow fan blade (1) is driven to rotate to the lowest point of the target blade.

4. The method for detecting an axial flow fan blade according to claim 3, wherein: Get the preset highest point angle value α of the target blade n and the preset lowest point angle value β of the target blade n The steps include: Before testing a batch of axial flow fan blades (1) of the same model, first install a standard axial flow fan blade of the same model on the rotating fixture (2); Setting the detection angle origin of the rotating fixture (2) and the axial flow fan blade (1); Rotate the rotary tool (2) and the axial flow fan blade (1) until the target blade passes the detection position of the visual detection device and detect the rotation angle relative to the detection angle origin, determine that the rotation is stopped when the highest point of the target blade is displayed at the highest height on the visual image of the visual detection device, and obtain the current rotation angle of the rotary tool (2) and the axial flow fan blade (1) as the preset highest point angle value α of the target blade n And save it for subsequent batch testing; The rotating tool (2) and the axial flow fan blade (1) are rotated until the target blade passes the detection position of the visual detection device and the rotation angle relative to the detection angle origin is detected. When the lowest point of the target blade is displayed at the lowest height on the visual image of the visual detection device, the rotation is stopped. The current rotation angle of the rotating tool (2) and the axial flow fan blade (1) is obtained as the preset lowest point angle value β of the target blade. n And save it for subsequent batch testing.

5. The method for detecting an axial flow fan blade according to claim 2, wherein: The step of obtaining the highest point of the blade in the highest point radial visual image comprises: The image processing system performs boundary fitting on the upper edge of the blade in the acquired radial visual image of the highest point to obtain an upper edge fitting line, wherein the highest point of the upper edge fitting line is the highest point of the blade; The step of obtaining the lowest point of the blade in the lowest point radial visual image comprises: The image processing system performs boundary fitting on the lower edge of the blade in the acquired radial visual image of the lowest point to obtain a lower edge fitting line, wherein the lowest point of the lower edge fitting line is the lowest point of the blade.

6. The method for detecting an axial flow fan blade according to claim 2, wherein: The method for obtaining the high reference line S1 includes: A high-position reference object (3) is provided on the upper side of the blade (11), and a straight line formed by the lower edge of the high-position reference object (3) in the radial visual image of the highest point is the high-position reference line S1; The method for obtaining the low reference line S2 includes: A fixed low-position reference object (4) is provided on the lower side of the blade (11), and a straight line formed by the lower edge of the low-position reference object (4) in the lowest point radial visual image is the low-position reference line S2.

7. The method for detecting an axial flow fan blade according to claim 2, wherein: Calculate the actual high position distance h n1 and the actual low bit spacing h n2 The steps include: The image processing system obtains the number of pixels P between the highest point of the blade and the high reference line S1 n1 , then the actual high position spacing h n1 =P n1 *T / P0; The image processing system obtains the number of pixels P between the lowest point of the leaf and the low reference line S2 n2 , then the actual low-level spacing h n2 =P n2 *T / P0; Among them, the visual detection device obtains a visual image of the thickness of the actual size reference object, and the image processing system obtains the number of pixels of the thickness of the actual size reference object in the visual image as P0; T is the actual size value of the thickness of the actual size reference object set.

8. The method for detecting an axial flow fan blade according to claim 2, wherein: In step S3, the height H of each blade (11) is calculated. n The methods include: Obtain the distance H0 between the upper reference line S1 and the lower reference line S2, then H n =H0-h n1 -h n2 .

9. The method for detecting an axial flow fan blade according to claim 2, wherein: The method for calculating the highest point axial runout of the highest points of the N blades (11) in step S3 is: High point axis runout = max (h n1 )-min(h n1 ), where max(h n1 ) is the actual height spacing h of the N blades (11) 11 、h 21 ...h N1 The maximum value, min (h n1 ) is the actual height spacing h of the N blades (11) 11 、h 21 ...h N1 The minimum value of The method for calculating the lowest point axial runout of the lowest points of the N blades (11) in step S3 is: Low point axis runout = max (h n2 )-min(h n2 ), where max(h n2 ) is the actual low position spacing h of the N blades (11) 12 、h 22 ...h N2 The maximum value, min (h n2 ) is the actual low position spacing h of the N blades (11) 12 、h 22 ...h N2 The minimum value of .

10. The method for detecting an axial flow fan blade according to claim 1, wherein: The visual inspection device comprises a high-position visual inspection camera (5) and a low-position visual inspection camera (6), wherein the high-position visual inspection camera (5) is arranged on the upper side of the low-position visual inspection camera (6), the high-position visual inspection camera (5) is arranged to match the height of the upper side of the axial flow fan blade (1), and the low-position visual inspection camera (6) is arranged to match the height of the lower side of the axial flow fan blade (1), the high-position visual inspection camera (5) is used to obtain the height position of the highest point of the blade (11), and the low-position visual inspection camera (6) is used to obtain the height position of the lowest point of the blade (11).

Images