Appearance detection device

Abstract

The utility model provides an appearance detection device. The appearance detection device comprises a case, a double-layer conveying device penetrates through the middle of the case, and the two ends of the double-layer conveying device are arranged outside the case. An image acquisition device is arranged in the case, and the double-layer conveying device comprises an upper-layer conveying device and a lower-layer conveying device. A driving device is arranged in the machine box and located on the lower side of the lower-layer conveying device, and the driving device drives the upper-layer conveying device and the lower-layer conveying device to operate synchronously in the same direction. During detection, a to-be-detected part is placed on the double-layer conveying device, one end of the to-be-detected part is placed on the upper-layer conveying device, the other end of the to-be-detected part is placed on the lower-layer conveying device, the to-be-detected part is kept in a horizontal state under the support of the upper-layer conveying device and the lower-layer conveying device, and the to-be-detected part is prevented from overturning. Parts to be detected are arranged according to a unified angle, the image acquisition device performs image acquisition, and the visual inspection system analyzes and compares acquired high-quality image information.

Description

Technical Field

[0001] The utility model relates to an appearance detection device, in particular to an appearance detection device with a double-layer conveyor belt. Background Art

[0002] In the field of industrial production and quality control, visual inspection solutions are used to quickly and accurately detect problems such as missing rivets and missing parts. By capturing images, the computer extracts features such as texture and shape from the captured images, and analyzes and compares these features through algorithms. If features that do not meet the preset standards are detected, an alarm is triggered or defective products are automatically removed to guide the production line to make adjustments.

[0003] The inspection system relies on comparison with known templates. When the inspection object is blocked, deformed, rotated, etc., the visual inspection system cannot maintain normal operation and the expected performance level. The objects to be inspected need to be arranged at a uniform angle so that the visual inspection system can obtain high-quality image information and ensure the accuracy and reliability of the inspection. It is difficult to arrange the existing pairs of bent sheet metal parts at a uniform angle, and it is impossible to ensure that the objects are in the correct position and angle, which affects the accuracy of the visual inspection system.

[0004] Therefore, the above situation needs to be resolved urgently. Utility Model Content

[0005] Purpose of the utility model: In order to overcome the above shortcomings, the utility model provides an appearance detection device with a double-layer conveyor belt.

[0006] Technical solution: In order to achieve the above-mentioned purpose, the utility model provides an appearance inspection device, including a chassis. A double-layer conveying device is provided in the middle of the chassis, and the two ends of the double-layer conveying device are provided on the outside of the chassis. An image acquisition device is provided inside the chassis, and the above-mentioned image acquisition device is provided on the upper side of the double-layer conveying device. The double-layer conveying device includes an upper conveying device and a lower conveying device. The upper conveying device is provided on the upper side of the lower conveying device, and the lower conveying device is provided on one side of the upper conveying device, and the upper conveying device and the lower conveying device are provided in parallel. A driving device is provided inside the chassis, and the driving device is provided on the lower side of the lower conveying device. The driving device is connected to the double-layer conveying device, and the driving device drives the upper conveying device and the lower conveying device to run synchronously and in the same direction. During the inspection, the parts to be tested are placed on the double-layer conveying device, one end of the parts to be tested is placed on the upper conveying device, and the other end of the parts to be tested is placed on the lower conveying device, and the parts to be tested are kept in a horizontal state under the support of the upper conveying device and the lower conveying device to avoid the parts to be tested from flipping over, so that the parts to be tested are arranged at a uniform angle. A first sensing device is provided on both sides of the lower conveying device, the first sensing device is connected to the lower conveying device, and the first sensing device is provided at the lower side of the image acquisition device. When the double-layer conveying device conveys the part to be tested to the lower side of the image acquisition device, the first sensing device is triggered, the first sensing device sends a signal, the image acquisition device receives the signal, and then the image acquisition device performs image acquisition, the image acquisition device obtains high-quality image information, and the visual inspection system analyzes and compares the obtained high-quality image information. The double-layer conveying device keeps the part to be tested in a horizontal state after the bending process, avoids flipping of the part to be tested during the movement, and ensures the accuracy and reliability of the detection.

[0007] Furthermore, in the above-mentioned appearance inspection device, the lower conveying device includes a left lower conveying device and a right lower conveying device, the left lower conveying device is arranged on the left side of the conveying direction of the upper conveying device, and the right lower conveying device is arranged on the right side of the conveying direction of the upper conveying device, the left lower conveying device, the right lower conveying device, and the upper conveying device are parallel to each other, and the left lower conveying device and the right lower conveying device are arranged on the same horizontal plane. If the part to be inspected is a left-right symmetrical part, the lower conveying device is set as a left lower conveying device and a right lower conveying device, and one end of the left-right symmetrical part to be inspected is placed on the upper conveying device, and the other end is placed on the left lower conveying device and the right lower conveying device, respectively, to ensure that the left-right symmetrical parts to be inspected are at the same horizontal angle.

[0008] Furthermore, in the above-mentioned appearance inspection device, the upper conveying device includes an upper bracket, a first upper guide roller, and a second upper guide roller. The first upper guide roller is arranged at one end of the upper bracket, the first upper guide roller is arranged at the starting end of the upper conveying device, and the second upper guide roller is arranged at the end of the upper bracket away from the first upper guide roller. The conveyor belt moves from the first upper guide roller to the second upper guide roller. The lower conveying device includes a lower bracket, a first lower guide roller, and a second lower guide roller. The first lower guide roller is arranged at one end of the lower bracket, the first lower guide roller is arranged at the starting end of the lower conveying device, and the second lower guide roller is arranged at the end of the lower bracket away from the first lower guide roller. The conveyor belt moves from the first lower guide roller to the second lower guide roller after the conveyor is looped around the first lower guide roller and the second lower guide roller.

[0009] Furthermore, in the above-mentioned appearance inspection device, the driving device includes a driving motor and a V-shaped roller group. The driving motor is arranged on the lower side of the lower conveying device, and the driving motor and the lower conveying device are fixedly connected. The V-shaped roller group is arranged on the lower side of the lower conveying device. The motor shaft of the driving motor is connected to the V-shaped roller group through a belt drive. The rolling direction of the V-shaped roller group is consistent with the conveying direction of the double-layer conveying device. The conveyor belt passes through the V-shaped roller group, the V-shaped roller group tightens the conveyor belt, and the driving motor drives the V-shaped roller group to rotate, thereby driving the belt to move.

[0010] Furthermore, in the above-mentioned appearance inspection device, the V-shaped roller group includes a tensioning roller, a first guide roller, a second guide roller, a third guide roller, and a fourth guide roller. The tensioning roller, the first guide roller, the second guide roller and the lower conveying device are connected in a rolling manner, the first guide roller and the second guide roller are arranged in parallel, the tensioning roller is arranged between the first guide roller and the second guide roller, the tensioning roller is arranged on the lower side of the first guide roller and the second guide roller, and the driving motor is connected to the tensioning roller through a belt. The third guide roller is arranged on the upper side of the first guide roller, the fourth guide roller is arranged on the upper side of the second guide roller, the third guide roller and the fourth guide roller are arranged in parallel, and the third guide roller and the fourth guide roller are connected in a rolling manner to the upper conveying device. The conveyor belt of the lower conveying device enters from the upper side of the second guide roller, bypasses the lower side of the tensioning roller, passes out from the first guide roller, and then bypasses the outer side of the first lower guide roller and the second lower guide roller to form a closed transmission loop.

[0011] Furthermore, in the above-mentioned appearance inspection device, a tensioning mechanism is provided at both ends of the tensioning roller, and the tensioning mechanism includes a connecting plate, which is provided at both ends of the tensioning roller, and the connecting plate is fixedly connected to the lower conveying device, and the connecting plate is provided with an adjustment plate, and the tensioning roller is adjusted and connected through the adjustment plate and the connecting plate. The adjustment plate is provided with an adjustment hole, and the adjustment hole is elliptical and the long axis is vertically arranged, and the connecting plate is provided with a threaded hole corresponding to the adjustment hole, and the screw passes through the adjustment hole and is screwed into the above threaded hole, and the adjustment plate slides along the adjustment hole. A limit plate is provided on the side of the connecting plate away from the adjustment plate, and the limit plate and the connecting plate are fixedly connected, and the limit plate is provided with an adjustment screw, and the adjustment screw is screwed into the threaded hole provided on the limit plate to squeeze the adjustment plate. The adjustment screw pushes the adjustment plate, and the adjustment plate slides downward along the adjustment hole, thereby driving the tensioning roller to move downward, thereby achieving the purpose of tensioning the conveyor belt.

[0012] Furthermore, in the above-mentioned appearance inspection device, the guiding mechanism includes a guide plate, an adjustment rod, and a support plate. The support plates are respectively arranged on both sides of the upper conveying device. The support plate is provided with a through hole, and the adjustment rod is inserted into the through hole, and the adjustment rod can slide in the through hole. The guide plate and the adjustment rod are fixedly connected, and the guide plates are arranged in pairs on the upper side of the upper conveying device to guide the parts to be tested. The adjustment rod can slide in the through hole and can adapt to parts to be tested of different widths.

[0013] Furthermore, in the above-mentioned appearance inspection device, a second sensing device is provided at the preset end position of the double-layer conveyor device, and the second sensing device is provided on both sides of the double-layer conveyor device. When the part to be tested is transmitted to the preset end position of the double-layer conveyor device, the second sensing device is triggered, and the second sensing device sends a signal. The machine receives the signal and sends an alarm to remind the worker to take it away, or the automatic robot arm takes the part away.

[0014] Furthermore, in the above appearance inspection device, a third sensing device is provided at the preset starting position of the double-layer conveyor device, and the third sensing device is provided on both sides of the double-layer conveyor device. The part to be inspected is placed at the preset starting position of the double-layer conveyor device, the third sensing device is triggered, the third sensing device sends a signal, the machine receives the signal, and the appearance inspection starts.

[0015] It can be seen from the above technical scheme that the utility model has the following beneficial effects: when the appearance inspection device of the utility model is inspecting, the parts to be tested are placed on the double-layer conveying device, and the parts to be tested are kept in a horizontal state under the support of the double-layer conveying device. The parts to be tested are arranged at a uniform angle to avoid flipping of the parts to be tested. The image acquisition device obtains high-quality image information of the parts, and the visual inspection system analyzes and compares the obtained high-quality image information to ensure the accuracy and reliability of the inspection. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of an appearance detection device of the utility model;

[0017] Figure 2 It is a partial schematic diagram of an appearance detection device of the utility model;

[0018] Figure 3 It is a partial enlarged view of the V-shaped roller group of the utility model;

[0019] Figure 4 It is a partial enlarged view of the tensioning mechanism of the utility model;

[0020] Figure 5 This is a schematic diagram of the detection work of the utility model;

[0021] Figure 6 It is a schematic diagram of the detection work of the utility model.

[0022] In the figure: 1, chassis, 2, double-layer conveying device, 21, upper conveying device, 211, upper bracket, 212, first upper guide roller, 213, second upper guide roller, 22, lower conveying device, 221, left lower conveying device, 222, right lower conveying device, 223, lower bracket, 224, first lower guide roller, 225, second lower guide roller, 23, guiding mechanism, 231, guide plate, 232, adjustment rod, 233, support plate, 2 4. First sensing device, 25. Second sensing device, 26. Third sensing device, 4. Driving device, 41. Driving motor, 42. V-shaped roller group, 421. Tensioning roller, 422. First guide roller, 423. Second guide roller, 424. Third guide roller, 425. Fourth guide roller, 5211. Adjusting plate, 5212. Connecting plate, 5213. Limiting plate, 5214. Adjusting screw, 5215. Adjusting hole, 6. Left part to be measured, 7. Right part to be measured. DETAILED DESCRIPTION

[0023] Example 1

[0024] like Figure 1-2An appearance inspection device shown includes a chassis 1. A double-layer conveying device 2 is inserted through the middle of the chassis 1, and both ends of the double-layer conveying device 2 are arranged on the outside of the chassis 1. An image acquisition device is arranged inside the chassis 1, and the above-mentioned image acquisition device is arranged on the upper side of the double-layer conveying device 2. The double-layer conveying device 2 includes an upper conveying device 21 and a lower conveying device 22. The upper conveying device 21 is arranged on the upper side of the lower conveying device 22, and the lower conveying device 22 is arranged on one side of the upper conveying device 21, and the upper conveying device 21 and the lower conveying device 22 are arranged in parallel. A driving device 4 is arranged inside the chassis 1, and the driving device 4 is arranged on the lower side of the lower conveying device 22. The driving device 4 is connected to the double-layer conveying device 2, and the driving device 4 drives the upper conveying device 21 and the lower conveying device 22 to run synchronously and in the same direction. During the inspection, the part to be tested is placed on the double-layer conveying device 2, with one end of the part to be tested placed on the upper conveying device 21, and the other end of the part to be tested placed on the lower conveying device 22. The parts to be tested are arranged at a uniform angle and maintained in a horizontal state under the support of the upper conveying device 21 and the lower conveying device 22. A first sensing device 24 is provided on both sides of the lower conveying device 22, and the first sensing device 24 is connected to the lower conveying device 22, and the first sensing device 24 is provided on the lower side of the image acquisition device. When the double-layer conveying device 2 transports the part to be tested to the lower side of the image acquisition device, the first sensing device 24 is triggered, the first sensing device 24 sends a signal, the image acquisition device receives the signal, and then the image acquisition device performs image acquisition, the image acquisition device obtains high-quality image information, and the visual inspection system analyzes and compares the obtained high-quality image information. The lower conveying device 22 includes a left lower conveying device 221 and a right lower conveying device 222. The left lower conveying device 221 is arranged on the left side of the conveying direction of the upper conveying device 21, and the right lower conveying device 222 is arranged on the right side of the conveying direction of the upper conveying device 21. The left lower conveying device 221, the right lower conveying device 222 and the upper conveying device 21 are parallel to each other, and the left lower conveying device 221 and the right lower conveying device 222 are arranged on the same horizontal plane. If the part to be tested is a left-right symmetrical part, the lower conveying device 22 is set as the left lower conveying device 221 and the right lower conveying device 222. One end of the left-right symmetrical part to be tested is placed on the upper conveying device 21, and the other end is placed on the left lower conveying device 221 and the right lower conveying device 222 respectively, so as to ensure that the left-right symmetrical part to be tested is at the same horizontal angle. The upper conveying device 21 includes an upper bracket 211, a first upper guide roller 212, and a second upper guide roller 213. The first upper guide roller 212 is disposed at one end of the upper support 211, the first upper guide roller 212 is disposed at the starting end of the upper conveying device 21, and the second upper guide roller 213 is disposed at one end of the upper support 211 away from the first upper guide roller 212. The conveyor belt moves from the first upper guide roller 212 to the second upper guide roller 213.The lower conveying device 22 includes a lower support 223, a first lower guide roller 224, and a second lower guide roller 225. The first lower guide roller 224 is arranged at one end of the lower support 223, the first lower guide roller 224 is arranged at the starting end of the lower conveying device 22, and the second lower guide roller 225 is arranged at the end of the lower support 223 away from the first lower guide roller 224. The conveyor belt is conveyed in a circle around the first lower guide roller 224 and the second lower guide roller, and the conveyor belt moves from the first lower guide roller 224 to the second lower guide roller 225. The driving device 4 includes a driving motor 41 and a V-shaped roller group 42. The driving motor 41 is arranged at the lower side of the lower conveying device 22, and the driving motor 41 and the lower conveying device 22 are fixedly connected. The V-shaped roller group 42 is arranged at the lower side of the lower conveying device 22, and the V-shaped roller group 42 and the lower conveying device 22 are rollingly connected. The motor shaft of the driving motor 41 is connected by a belt and a V-shaped roller group 42, and the rolling direction of the V-shaped roller group 42 is consistent with the conveying direction of the double-layer conveying device 2. The conveyor belt passes through the V-shaped roller group 42, and the V-shaped roller group 42 tightens the conveyor belt. The driving motor 41 drives the V-shaped roller group 42 to rotate, thereby driving the belt to move. The guiding mechanism 23 includes a guide plate 231, an adjustment rod 232, and a support plate 233. The support plates 233 are respectively arranged on both sides of the upper conveying device 21. The support plate 233 is provided with a through hole, and the adjustment rod 232 is inserted into the above-mentioned through hole, and the adjustment rod 232 slides in the through hole. The guide plate 231 and the adjustment rod 232 are fixedly connected, and the guide plates 231 are arranged in pairs on the upper side of the upper conveying device 21 to guide the parts to be measured. A second sensing device 25 is provided at the preset end position of the double-layer conveying device 2, and the second sensing device 25 is arranged on both sides of the double-layer conveying device 2. When the part to be tested is transmitted to the preset end position of the double-layer conveyor 2, the second sensing device 25 is triggered, and the second sensing device 25 sends a signal. The machine receives the signal and sends an alarm to remind the worker to take it away, or the automatic robot arm takes the part away. A third sensing device 26 is provided at the preset starting position of the double-layer conveyor 2, and the third sensing device 26 is provided on both sides of the double-layer conveyor 2. The part to be tested is placed at the preset starting position of the double-layer conveyor 2, and the third sensing device 26 is triggered. The third sensing device 26 sends a signal, and the machine receives the signal to start appearance inspection. A positioning baffle is provided at the preset starting point position of the upper conveyor 21, and the positioning baffle is connected to both sides of the upper conveyor 21. The positioning baffle is provided on the upper conveyor 21 away from the upper side of the chassis 1. The positioning baffle positions the part to be tested in the conveying direction of the double-layer conveyor 2 to ensure that the part to be tested is at the preset starting point position, and the third sensing device 26 is triggered.

[0025] like Figure 3In the embodiment of the appearance inspection device shown in the figure, the V-shaped roller group 42 includes a tensioning roller 421, a first guide roller 422, a second guide roller 423, a third guide roller 424, and a fourth guide roller 425. The tensioning roller 421, the first guide roller 422, the second guide roller 423 and the lower conveying device 22 are connected in a rolling manner. The first guide roller 422 and the second guide roller 423 are arranged in parallel. The tensioning roller 421 is arranged between the first guide roller 422 and the second guide roller 423. The tensioning roller 421 is arranged on the lower side of the first guide roller 422 and the second guide roller 423. The driving motor 41 is connected to the tensioning roller 421 through a belt. The third guide roller 424 is arranged on the upper side of the first guide roller 422, the fourth guide roller 425 is arranged on the upper side of the second guide roller 423, the third guide roller 424 and the fourth guide roller 425 are arranged in parallel, and the third guide roller 424 and the fourth guide roller 425 are connected in a rolling manner to the upper conveying device 21. The conveyor belt of the lower conveying device 22 passes through the upper side of the second guide roller 423, passes around the lower side of the tensioning roller 421, passes out from the first guide roller 422, and then passes around the outside of the first lower guide roller 224 and the second lower guide roller 225 to form a closed transmission loop.

[0026] like Figure 4 In the appearance inspection device shown, a tensioning mechanism is provided at both ends of the tensioning roller 421, and the tensioning mechanism includes a connecting plate 5212, which is provided at both ends of the tensioning roller 421, and the connecting plate 5212 is fixedly connected to the lower conveying device 22, and the connecting plate 5212 is provided with an adjustment plate 5211, and the tensioning roller 421 is adjusted and connected through the adjustment plate 5211 and the connecting plate 5212. The adjustment plate 5211 is provided with an adjustment hole 5215, and the adjustment hole 5215 is elliptical and the long axis is vertically arranged, and the connecting plate 5212 is provided with a threaded hole corresponding to the adjustment hole 5215, and the screw passes through the adjustment hole 5215 and is screwed into the above-mentioned threaded hole, and the adjustment plate 5211 slides along the adjustment hole 5215. A limiting plate 5213 is provided on the side of the connecting plate 5212 away from the adjusting plate 5211. The limiting plate 5213 and the connecting plate 5212 are fixedly connected. The limiting plate 5213 is provided with an adjusting screw 5214. The adjusting screw 5214 is screwed into the threaded hole provided in the limiting plate 5213 to squeeze the adjusting plate 5211. The adjusting screw 5214 is adjusted to push the adjusting plate 5211, and the adjusting plate 5211 slides downward along the adjusting hole 5215, thereby driving the tensioning roller 421 to move downward and tighten the conveyor belt.

[0027] The above embodiments are exemplary, and their purpose is to illustrate the technical concept and features of the utility model so that people familiar with this field can understand the content of the utility model and implement it accordingly, and they cannot limit the protection scope of the utility model in turn. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. An appearance inspection device, characterized in that: The invention comprises a chassis (1); a double-layer conveying device (2) is provided in the middle of the chassis (1), and two ends of the double-layer conveying device (2) are arranged outside the chassis (1); an image acquisition device is provided inside the chassis (1), and the image acquisition device is arranged on the upper side of the double-layer conveying device (2); the double-layer conveying device (2) comprises an upper conveying device (21) and a lower conveying device (22); the upper conveying device (21) is arranged on the upper side of the lower conveying device (22), and the lower conveying device (22) is arranged on one side of the upper conveying device (21), and the upper conveying device (21) and the lower conveying device (22) are arranged on the upper side of the lower conveying device (22). The conveying devices (22) are arranged in parallel; a driving device (4) is arranged inside the chassis (1), the driving device (4) is arranged on the lower side of the lower conveying device (22), the driving device (4) and the double-layer conveying device (2) are connected by driving, and the driving device (4) drives the upper conveying device (21) and the lower conveying device (22) to run synchronously in the same direction; first sensing devices (24) are arranged on both sides of the lower conveying device (22), the first sensing device (24) is connected to the lower conveying device (22), and the first sensing device (24) is arranged on the lower side of the image acquisition device (3).

2. The appearance inspection device according to claim 1, characterized in that: The lower-layer conveying device (22) comprises a left-side lower-layer conveying device (221) and a right-side lower-layer conveying device (222); the left-side lower-layer conveying device (221) is arranged on the left side of the conveying direction of the upper-layer conveying device (21); the right-side lower-layer conveying device (222) is arranged on the right side of the conveying direction of the upper-layer conveying device (21); the left-side lower-layer conveying device (221), the right-side lower-layer conveying device (222) and the upper-layer conveying device (21) are parallel to each other; and the left-side lower-layer conveying device (221) and the right-side lower-layer conveying device (222) are arranged on the same horizontal plane.

3. The appearance inspection device according to claim 1, characterized in that: The upper conveying device (21) comprises an upper support (211), a first upper guide roller (212), and a second upper guide roller (213); the first upper guide roller (212) is arranged at one end of the upper support (211), the first upper guide roller (212) is arranged at a starting end of the upper conveying device (21), and the second upper guide roller (213) is arranged at an end of the upper support (211) away from the first upper guide roller (212); the conveyor belt moves from the first upper guide roller (212) to the second upper guide roller (213); The lower layer conveying device (22) comprises a lower layer support (223), a first lower layer guide roller (224), and a second lower layer guide roller (225); the first lower layer guide roller (224) is arranged at one end of the lower layer support (223), the first lower layer guide roller (224) is arranged at a starting end of the lower layer conveying device (22), and the second lower layer guide roller (225) is arranged at an end of the lower layer support (223) away from the first lower layer guide roller (224); and the conveyor belt moves from the first lower layer guide roller (224) to the second lower layer guide roller (225).

4. The appearance inspection device according to claim 1, characterized in that: The driving device (4) comprises a driving motor (41) and a V-shaped roller group (42); the driving motor (41) is arranged at the lower side of the lower conveying device (22), and the driving motor (41) and the lower conveying device (22) are fixedly connected; the V-shaped roller group (42) is arranged at the lower side of the lower conveying device (22), and the V-shaped roller group (42) and the lower conveying device (22) are rollingly connected; the motor shaft of the driving motor (41) is drivingly connected to the V-shaped roller group (42) via a belt; and the rolling direction of the V-shaped roller group (42) is consistent with the conveying direction of the double-layer conveying device (2).

5. The appearance inspection device according to claim 4, characterized in that: The V-shaped roller group (42) comprises a tensioning roller (421), a first guide roller (422), a second guide roller (423), a third guide roller (424), and a fourth guide roller (425); the tensioning roller (421), the first guide roller (422), the second guide roller (423) and the lower conveying device (22) are rollingly connected, the first guide roller (422) and the second guide roller (423) are arranged in parallel, the tensioning roller (421) is arranged between the first guide roller (422) and the second guide roller (423), and the tensioning roller (421) is arranged between the first guide roller (422) and the second guide roller (423). The roller (421) is arranged at the lower side of the first guide roller (422) and the second guide roller (423), and the driving motor (41) is connected to the tensioning roller (421) through a belt; the third guide roller (424) is arranged at the upper side of the first guide roller (422), and the fourth guide roller (425) is arranged at the upper side of the second guide roller (423); the third guide roller (424) and the fourth guide roller (425) are arranged in parallel, and the third guide roller (424) and the fourth guide roller (425) are connected to the upper conveying device (21) in a rolling manner.

6. The appearance inspection device according to claim 5, characterized in that: A tensioning mechanism is provided at both ends of the tensioning roller (421), and the tensioning mechanism comprises a connecting plate (5212). The connecting plate (5212) is provided at both ends of the tensioning roller (421), and the connecting plate (5212) is fixedly connected to the lower conveying device (22). The connecting plate (5212) is provided with an adjustment plate (5211), and the tensioning roller (421) is adjustably connected via the adjustment plate (5211) and the connecting plate (5212); the adjustment plate (5211) is provided with an adjustment hole (5215), and the adjustment hole (5215) is elliptical with the major axis arranged vertically. (5212) is provided with a threaded hole corresponding to the adjustment hole (5215), a screw passes through the adjustment hole (5215) and is screwed into the above-mentioned threaded hole, and the adjustment plate (5211) slides along the adjustment hole (5215); a limiting plate (5213) is provided on the side of the connecting plate (5212) away from the adjustment plate (5211), the limiting plate (5213) and the connecting plate (5212) are fixedly connected, and the limiting plate (5213) is provided with an adjusting screw (5214), and the adjusting screw (5214) is screwed into the threaded hole provided on the limiting plate (5213) to squeeze the adjustment plate (5211).

7. The appearance inspection device according to claim 1, characterized in that: A guiding mechanism (23) is provided on the upper side of the upper conveying device (21), and the guiding mechanism (23) is arranged at a preset starting point position of the upper conveying device (21).

8. The appearance inspection device according to claim 7, characterized in that: The guiding mechanism (23) comprises a guide plate (231), an adjusting rod (232), and a support plate (233); the support plates (233) are respectively arranged on both sides of the upper conveying device (21), and the support plates (233) and the upper conveying device (21) are fixedly connected; the support plate (233) is provided with a through hole, the adjusting rod (232) penetrates into the through hole, and the adjusting rod (232) can slide in the through hole; the guide plate (231) and the adjusting rod (232) are fixedly connected, and the guide plates (231) are arranged in pairs on the upper side of the upper conveying device (21) to guide the parts to be measured.

9. The appearance inspection device according to claim 1, characterized in that: A second sensing device (25) is provided at a preset end position of the double-layer conveying device (2), and the second sensing device (25) is provided on both sides of the double-layer conveying device (2).

10. The appearance inspection device according to claim 1, characterized in that: A third sensing device (26) is provided at a preset starting point position of the double-layer conveying device (2), and the third sensing device (26) is provided on both sides of the double-layer conveying device (2).

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