Visual inspection method for cross-flow fan blade

Abstract

The visual detection method comprises the steps that a to-be-detected cross-flow fan blade is fed to a detection station and located and clamped, a visual detection device is arranged on the detection station, and the visual detection device comprises a detection camera, a coaxial light source and a back side light source; the coaxial light source and the back side light source are arranged in the circumferential direction of the rotation axis of the cross-flow fan blade, and the included angle ranges from 90 degrees to 130 degrees. And meanwhile, the detection camera shoots the cross-flow fan to obtain an image of the whole periphery of the cross-flow fan. The included angle between the irradiation direction of the coaxial light source and the irradiation direction of the back side light source is 90-130 degrees, under the light within the range of the included angle, the light of the back side light source and the light of the coaxial light source jointly form a good light effect in a shooting area on the cross-flow fan blade, defects on the blade can be more obviously highlighted, the detection precision is improved, and the detection efficiency is improved. Therefore, automatic visual detection of the cross-flow fan blade is realized, and the shooting and detection effects are improved.

Description

Technical Field

[0001] This invention relates to the field of cross-flow fan blade inspection technology, and in particular to a visual inspection method for cross-flow fan blades. Background Technology

[0002] As a core component in air conditioners, household fans, and other equipment that generates airflow, the quality of cross-flow fan blades directly affects the overall performance and reliability of the machine. During the production process, cross-flow fan blades undergo multiple quality inspections. Visual inspection, in particular, identifies defects such as pits, deformation, and misalignment on the blade surface, and is a crucial step in ensuring that the product meets quality standards.

[0003] Currently, the industry primarily relies on manual methods for the visual inspection of cross-flow fan blades, where operators hold the products and inspect them one by one by visual inspection. This method is not only labor-intensive, costly, and inefficient, but also susceptible to subjective factors and visual fatigue, easily leading to missed inspections and misjudgments, making it difficult to meet the consistency and reliability requirements of large-scale production. Although some companies have attempted to use visual inspection systems to replace manual labor, capturing images with cameras and identifying defects, the inspection results are not ideal, and the inspection methods are complex. Summary of the Invention

[0004] The main objective of this invention is to propose a visual inspection method for cross-flow fan blades, aiming to solve the technical problems of low efficiency, high labor costs, and easy omissions and errors in the existing technology that rely on manual visual inspection, as well as the poor detection effect and complex detection method of visual camera inspection.

[0005] To achieve the above objectives, this invention proposes a visual inspection method for cross-flow fan blades, comprising: The cross-flow fan blade to be inspected is loaded into the inspection station, and positioned and clamped. The inspection station is equipped with a vision inspection device, which includes an inspection camera, a coaxial light source, and a back-side light source. The coaxial light source and the back-side light source are arranged circumferentially along the rotation axis of the cross-flow fan blade. The illumination directions of the coaxial light source and the back-side light source are both facing the cross-flow fan blade. The angle between the illumination directions of the coaxial light source and the back-side light source is 90-130 degrees. The inspection camera is coaxially set with the coaxial light source and is located on the side of the coaxial light source away from the cross-flow fan blade. The cross-flow fan blades rotate, and the detection camera simultaneously captures images of the cross-flow fan blades to obtain an image of the entire outer circumference of the cross-flow fan blades.

[0006] The cross-flow fan blades to be inspected are loaded, positioned, and clamped at the inspection station. During inspection, the cross-flow fan blades rotate. A visual inspection device is installed at the inspection station, and the inspection camera photographs the cross-flow fan blades. Coaxial light sources and back-side light sources are arranged circumferentially around the cross-flow fan blades and illuminate them. The angle between the illumination directions of the coaxial light source and the back-side light source is 90-130 degrees. Under the light within this angle range, the light from the back-side light source and the light from the coaxial light source together form a better lighting effect on the imaging area of ​​the cross-flow fan blades, making defects on the blades more obvious and improving the inspection accuracy. This enables automatic visual inspection of cross-flow fan blades and improves the imaging and inspection effects.

[0007] Preferably, the left-right direction is defined by the axis of the cross-flow fan blades; The coaxial light source and the back-side light source are respectively located on the upper front side and the upper rear side of the cross-flow fan blade; Alternatively, the coaxial light source and the rear-side light source are respectively located on the lower front side and the lower rear side of the cross-flow fan blade; Alternatively, the coaxial light source and the back-side light source are respectively located on the upper front side and the lower front side of the cross-flow fan blade; Alternatively, the coaxial light source and the back-side light source are respectively located on the upper rear side and the lower rear side of the cross-flow fan blade; Alternatively, one of the coaxial light source and the back-side light source may be located on the top, bottom, front, or rear side of the cross-flow fan blade.

[0008] Preferably, there are multiple detection cameras, which are arranged sequentially along the axis of the cross-flow fan blades, and each camera captures images of the cross-flow fan blades at different axial positions.

[0009] Preferably, the number of detection cameras is one, and the visual detection device further includes a camera movement drive unit. The detection camera is disposed on the moving end of the camera movement drive unit, and the camera movement drive unit can drive the detection camera to move along the axis of the cross-flow fan blade to capture images of the cross-flow fan blade at different axial positions.

[0010] Preferably, the visual inspection method includes blade defect detection and overall length detection; The blade defect detection includes acquiring images of the cross-flow fan blade at multiple positions along its length corresponding to different rotation angles, and analyzing whether there are defect features in the images; The overall length detection includes acquiring images of the end plates at both ends of the cross-flow fan blade, and determining the distance between the two end plates based on the position of the end plates in the images to obtain the overall length of the cross-flow fan blade.

[0011] Preferably, for cross-flow fan blades with D-shaped end holes, when using the clamping method of inserting the expansion shaft into the D-shaped end hole, before inserting the expansion shaft into the D-shaped end hole, the cross-flow fan blade is rotated and the origin feature position of the cross-flow fan blade is detected simultaneously. The angle of the D-shaped end hole is determined by the origin feature position of the cross-flow fan blade, and then the expansion shaft is inserted into the D-shaped end hole. Before inserting the expansion shaft into the D-shaped end hole, it is necessary to first determine and detect the origin feature position of the cross-flow fan blade to correspond to the position of the plane of the D-shaped end hole, so that the expansion shaft can be accurately inserted into the D-shaped end hole. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. 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 creative effort.

[0013] Figure 1 This is a schematic diagram showing the positions of the cross-flow fan blades, detection camera, coaxial light source, and back-side light source of the present invention. Figure 1 ; Figure 2 This is a schematic diagram showing the positions of the cross-flow fan blades, detection camera, coaxial light source, and back-side light source of the present invention. Figure 2 ; Figure 3 This is a schematic diagram showing the positions of the cross-flow fan blades, detection camera, coaxial light source, and back-side light source of the present invention. Figure 3 .

[0014] In the attached diagram: 1-Cross-flow fan blade, 21-Detection camera, 22-Coaxial light source, 23-Backside light source.

[0015] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] It should be noted that if the embodiments of the present invention involve directional indicators, such as up, down, left, right, front, back, etc., the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0018] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0019] like Figures 1 to 3 As shown, a visual inspection method for cross-flow fan blades includes the following steps: The cross-flow fan blade 1 to be inspected is loaded into the inspection station, and positioned and clamped. The inspection station is equipped with a vision inspection device, which includes an inspection camera 21, a coaxial light source 22, and a back-side light source 23. The coaxial light source 22 and the back-side light source 23 are arranged circumferentially along the rotation axis of the cross-flow fan blade 1. The illumination direction of the coaxial light source 22 and the illumination direction of the back-side light source 23 are both towards the axis of the cross-flow fan blade 1. The angle between the illumination direction of the coaxial light source 22 and the illumination direction of the back-side light source 23 is 90-130 degrees. The inspection camera 21 is coaxially set with the coaxial light source 22 and is located on the side of the coaxial light source 22 away from the cross-flow fan blade 1. The cross-flow fan blade 1 is driven to rotate, and at the same time the detection camera 21 takes pictures of the cross-flow fan blade 1 to obtain an image of the entire outer periphery of the cross-flow fan blade 1.

[0020] The cross-flow fan blade 1 to be inspected is loaded onto the inspection station for positioning and clamping. The clamping method can be set according to the shape of the cross-flow fan blade 1's shaft hole, such as a round hole or a D-shaped hole, using an insertion expansion shaft method or a clamping end shaft method. During inspection, the cross-flow fan blade 1 is rotated. A visual inspection device is set up at the inspection station, and the inspection camera 21 photographs the cross-flow fan blade 1. A coaxial light source 22 and a back-side light source 23 are arranged circumferentially around the cross-flow fan blade 1 and illuminate it. The angle between the illumination directions of the coaxial light source 22 and the back-side light source 23 is 90-130 degrees. Under the light within this angle range, the light from the back-side light source 23 and the light from the coaxial light source 22 together form a good lighting effect on the imaging area of ​​the cross-flow fan blade 1, making defects on the blade more obvious and improving the inspection accuracy. This achieves automatic visual inspection of the cross-flow fan blade 1, improving the imaging and inspection effects. In addition, at this angle, the illumination range can be adapted to inspect cross-flow fan blades 1 of different diameters.

[0021] In some specific embodiments, with the axial direction of the cross-flow fan blade 1 as the left-right direction, the coaxial light source 22 and the back-side light source 23 can be set at different positions of the cross-flow fan blade 1 for detection, for example: Reference Figure 2 The coaxial light source 22 and the back side light source 23 are respectively located on the upper front side and the upper rear side of the cross-flow fan blade 1. Both the coaxial light source 22 and the back side light source 23 are tilted downward to illuminate the cross-flow fan blade 1. Alternatively, the coaxial light source 22 and the backside light source 23 are respectively located on the lower front side and the lower rear side of the cross-flow fan blade 1, and both the coaxial light source 22 and the backside light source 23 are tilted upward to illuminate the cross-flow fan blade 1. Or, refer to Figure 3 The coaxial light source 22 and the back side light source 23 are respectively located on the upper front side and the lower front side of the cross-flow fan blade 1. Both the coaxial light source 22 and the back side light source 23 are tilted to illuminate the cross-flow fan blade 1 backward. Alternatively, the coaxial light source 22 and the back-side light source 23 are respectively located on the upper rear side and the lower rear side of the cross-flow fan blade 1, and both the coaxial light source 22 and the back-side light source 23 are tilted forward to illuminate the cross-flow fan blade 1. Or, refer to Figure 1 One of the coaxial light source 22 and the back-side light source 23 is located on the top, bottom, front, or rear side of the cross-flow fan blade 1. One of the coaxial light source 22 and the back-side light source 23 illuminates the cross-flow fan blade 1 directly, while the other illuminates the cross-flow fan blade 1 at an angle.

[0022] In some specific embodiments, there are multiple detection cameras 21, which are arranged sequentially along the axial direction of the cross-flow fan blade 1. The multiple detection cameras 21 capture images of the cross-flow fan blade 1 at different axial positions, and the multiple detection cameras 21 do not need to move left or right during the detection process.

[0023] In some other embodiments, the number of detection cameras 21 is one, and the visual inspection device also includes a camera movement drive unit. The detection camera 21 is disposed on the moving end of the camera movement drive unit. The camera movement drive unit can drive the detection camera 21 to move along the axial direction of the cross-flow fan blade 1 to capture images of the cross-flow fan blade 1 at different axial positions. After the detection camera 21 captures an image at one axial position, it moves a certain distance to another axial position to capture an image.

[0024] In some specific embodiments, the visual inspection method includes blade defect detection and overall length detection; Blade defect detection includes acquiring images of the cross-flow fan blade 1 at multiple positions along its length corresponding to different rotation angles, and analyzing whether there are defect features in the images; The overall length detection includes acquiring images of the end plates at both ends of the cross-flow fan blade 1, and determining the distance between the two end plates based on the position of the end plates in the images to obtain the overall length of the cross-flow fan blade 1.

[0025] On the one hand, visual inspection can detect defects in the blades, such as dents, scratches, or deformations, through image analysis; on the other hand, cameras located at the left and right ends can detect the ends of the cross-flow fan blade 1 and obtain the distance between the two ends, thereby determining whether the length of the cross-flow fan blade 1 is up to standard.

[0026] In some specific embodiments, for a cross-flow fan blade 1 with a D-shaped end hole, when the clamping method of inserting the expansion shaft into the D-shaped end hole is adopted, before inserting the expansion shaft into the D-shaped end hole, the cross-flow fan blade 1 is rotated and the origin feature position of the cross-flow fan blade 1 is detected at the same time. The angle of the D-shaped end hole is determined by the origin feature position of the cross-flow fan blade 1, and then the expansion shaft is inserted into the D-shaped end hole.

[0027] Because the angular position of the cross-flow fan blade 1 is uncertain during loading, and the inner arm of the D-shaped end hole includes a side plane, the expansion shaft can only be inserted into the D-shaped end hole if its angle corresponds to this side plane. After the expansion shaft is inserted into the D-shaped end hole, it will expand outward and fit tightly against the D-shaped end hole to achieve clamping. Therefore, before inserting the expansion shaft into the D-shaped end hole, it is necessary to first determine the origin feature position of the cross-flow fan blade 1 to correspond to the position of the plane of the D-shaped end hole, so that the expansion shaft can be accurately inserted into the D-shaped end hole. The origin feature position of the cross-flow fan blade 1 can be a feature point on the end plate of the cross-flow fan blade 1 or a fixing screw hole on the D-shaped end hole, etc. The origin detection device can specifically detect the rotating cross-flow fan blade 1 through a laser sensor.

[0028] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A visual inspection method for cross-flow fan blades, characterized in that, include: The cross-flow fan blade (1) to be inspected is loaded to the inspection station, and the cross-flow fan blade (1) is positioned and clamped. A visual inspection device is provided at the inspection station. The visual inspection device includes an inspection camera (21), a coaxial light source (22), and a back-side light source (23). The coaxial light source (22) and the back-side light source (23) are arranged circumferentially along the rotation axis of the cross-flow fan blade (1). The irradiation direction of the coaxial light source (22) and the irradiation direction of the back-side light source (23) are both facing the cross-flow fan blade (1). The angle between the irradiation direction of the coaxial light source (22) and the irradiation direction of the back-side light source (23) is 90-130 degrees. The inspection camera (21) is coaxially set with the coaxial light source (22). The inspection camera (21) is located on the side of the coaxial light source (22) away from the cross-flow fan blade (1). The cross-flow fan blade (1) is rotated, and the detection camera (21) takes pictures of the cross-flow fan blade (1) to obtain an image of the entire outer periphery of the cross-flow fan blade (1).

2. The visual inspection method as described in claim 1, characterized in that, The left and right directions are defined by the axis of the cross-flow fan blade (1); The coaxial light source (22) and the rear-side light source (23) are respectively located on the upper front side and the upper rear side of the cross-flow fan blade (1); Alternatively, the coaxial light source (22) and the rear-side light source (23) are respectively located on the lower front side and the lower rear side of the cross-flow fan blade (1); Alternatively, the coaxial light source (22) and the back-side light source (23) are respectively located on the upper front side and the lower front side of the cross-flow fan blade (1); Alternatively, the coaxial light source (22) and the rear-side light source (23) are respectively located on the upper rear side and the lower rear side of the cross-flow fan blade (1); Alternatively, one of the coaxial light source (22) and the back-side light source (23) may be located on the top, bottom, front, or rear side of the cross-flow fan blade (1).

3. The visual inspection method as described in claim 1, characterized in that, The number of detection cameras (21) is multiple, and the multiple detection cameras (21) are arranged sequentially along the axis of the cross-flow fan blade (1). The multiple detection cameras (21) respectively capture images of the cross-flow fan blade (1) at different axial positions.

4. The visual inspection method as described in claim 1, characterized in that, The number of detection cameras (21) is one. The visual detection device also includes a camera movement drive unit. The detection camera (21) is located on the moving end of the camera movement drive unit. The camera movement drive unit can drive the detection camera (21) to move along the axis of the cross-flow fan (1) to capture images of the cross-flow fan (1) at different axial positions.

5. The visual inspection method as described in claim 1, characterized in that, The visual inspection method includes blade defect detection and overall length detection; The blade defect detection includes acquiring images of the cross-flow fan blade (1) at multiple positions along its length corresponding to different rotation angles, and analyzing whether there are defect features in the images; The overall length detection includes acquiring images of the end plates at both ends of the cross-flow fan blade (1) and determining the distance between the two end plates based on the position of the end plates in the images to obtain the overall length of the cross-flow fan blade (1).

6. The visual inspection method as described in claim 1, characterized in that, For a cross-flow fan blade (1) with a D-shaped end hole, when using the clamping method of inserting the expansion shaft into the D-shaped end hole, before inserting the expansion shaft into the D-shaped end hole, first rotate the cross-flow fan blade (1) and simultaneously detect the origin feature position of the cross-flow fan blade (1), determine the angle of the D-shaped end hole based on the origin feature position of the cross-flow fan blade (1), and then insert the expansion shaft into the D-shaped end hole.

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