Visual sensor protective cover with foreign matter removal function and foreign matter removal method

Abstract

The invention provides a visual sensor protective cover with a foreign matter removal function and a foreign matter removal method. The visual sensor protective cover comprises a window assembly and a cover body, the window assembly comprises a window body and a connecting piece; the window body is provided with protective glass; a triangular groove is formed in one side of the connecting piece, and a through groove is formed in the opposite side of the connecting piece; the cover body is arranged at the front end of the window assembly and can shield or expose the window assembly; when the cover shields the window body, the gas pipe is filled with high-pressure gas at the moment; the front wall of the window body is provided with a first slope and a second slope which are sequentially connected, the first slope and one face of the triangular groove form an acute angle cavity, and the second slope and the other face of the triangular groove are flow guide faces. The window assembly designed in the device enables the wind direction to be strong and scrape the protective glass from top to bottom; the device has the characteristics of high removal rate and convenience in installation, and meets the use requirements of the visual sensor in a severe environment.

Description

Technical Field

[0001] The present invention relates to the field of mechanical design, and in particular to a visual sensor protective cover with a foreign matter removal function and a foreign matter removal method. Background Art

[0002] With the continuous development of machine vision inspection technology, it is now widely used in various industries. Different production environments have created different usage requirements. For example, in the die-casting workshop, characterized by high humidity, dust, interference, and oil mist infiltration, the sensor camera lens is easily contaminated in such a harsh environment. Foreign matter such as oil and dust can adhere to the sensor, affecting the image quality. Therefore, it is necessary to strengthen the protection level requirements of the visual inspection sensor system.

[0003] In existing designs, the visual sensor is fixed to the front end of a motion system, which controls the sensor's position. When the visual sensor is required, it is pushed into the inspection station and when not, it is withdrawn. This reduces the time the sensor is exposed to harsh environments and reduces the accumulation of oil mist and dust on the sensor. However, this approach does not improve the visual sensor's resistance to oil mist, dust, and water vapor. Even after extended use, the sensor can still be obstructed by foreign matter, affecting image acquisition quality.

[0004] Patent document CN210005424U discloses a sensor protection device that uses a blower to continuously blow air onto the sensor's acquisition terminal while the cover is not completely covering it. This blows away dust on the camera's front window glass, effectively removing it. However, this solution only removes low-viscosity attachments such as dust and is less effective for removing higher-viscosity attachments such as moisture and oil.

[0005] Therefore, the main innovation of this invention is how to ensure that the sensor cycle is not limited in this harsh environment, can be combined with normal mold production speed measurement, and the production cost is low. Summary of the Invention

[0006] To address the aforementioned technical issues, the present invention provides a visual sensor protective cover and method for removing foreign matter. This device features an openable cover. When the protective glass is within the cavity, the window assembly provides a strong wind direction through the air duct, forming a wind knife that scrapes across the protective glass from top to bottom. This design not only removes low-viscosity foreign matter such as dust, but also removes higher-viscosity foreign matter such as moisture and oil. It boasts a high removal rate and is easy to install, meeting the requirements for visual sensors in harsh environments.

[0007] The technical solution is as follows:

[0008] A visual sensor protective cover with a foreign matter removal function, comprising a window assembly and a cover body;

[0009] The window assembly includes a window body and a connector; the window body is fixed to the front end of the camera lens of the visual sensor, and a protective glass is installed in the middle area of ​​the window body; the protective glass is located at a plane slightly lower than the front wall of the window body after installation; the connector is in the shape of a U-shaped or ring-shaped member so as not to obstruct the camera's field of view; the connector is fixed to the front wall of the window body, and has a triangular groove on one side and a through groove on the opposite side, the through groove forming a narrow gap between the connector and the window body; the opening of the triangular groove faces the protective glass, and through holes are provided on the side walls of the connector at both ends of the triangular groove corresponding to the ends for connecting to the air pipe;

[0010] The cover is arranged at the front end of the window assembly, and can block or reveal the window assembly; when the cover blocks the window assembly, a cavity is formed between the window body, the connector, and the cover, and the air pipe is filled with high-pressure gas (0.7-1.3 MPa) at this time;

[0011] The front wall of the window body is provided with a first slope surface and a second slope surface connected in sequence at the position corresponding to the triangular groove. The first slope surface and one surface of the triangular groove form an acute-angle cavity, and the second slope surface and the other surface of the triangular groove are both guide surfaces. After the gas enters the acute-angle cavity through the air pipe and is squeezed and pressurized by the acute-angle cavity, the gas can be guided to the surface of the protective glass, and finally the gas is discharged from the cavity along the through groove.

[0012] Preferably, the cross section of the triangular groove is a right triangle or an obtuse triangle, the smallest angle in the triangle is 10° to 40°, the surface where the angle is located is opposite to the second slope surface, and both are guide surfaces.

[0013] Preferably, the width of the triangular groove is equal to or greater than the width of the cover glass.

[0014] Preferably, the angle β between the first slope and the plane where the protective glass is located is 5° to 20°; the angle α between the second slope and the plane where the protective glass is located is 20° to 60°.

[0015] Preferably, the minimum height difference H between the second slope surface and the plane where the protective glass is located is 0.1 to 0.5 cm.

[0016] Furthermore, the cover body is connected to a cylinder, and the cylinder can control the cover body to rotate at the front end of the window assembly to achieve up and down opening and closing.

[0017] Furthermore, the cylinder is mounted on a support base and controlled by a first solenoid valve. The support base is fixed to the surface of the visual sensor housing, and the cover is hinged at the front end of the support base. The piston rod of the cylinder is hinged to the cover. The first solenoid valve controls the piston rod in the cylinder to retract backward, thereby pulling the cover open. Alternatively, the first solenoid valve controls the piston rod in the cylinder to advance forward, pushing the cover downward to close and cover the connector.

[0018] The air pipe is controlled by a second solenoid valve, and the second solenoid valve controls air intake into the air pipe.

[0019] Preferably, the cylinder is a double-acting cylinder, the first solenoid valve is a two-position four-way solenoid valve, and the second solenoid valve is a two-position three-way solenoid valve.

[0020] Alternatively, the cover is connected to a motor, and the motor can control the cover to move horizontally at the front end of the window assembly to open and close left and right.

[0021] The present invention also discloses a method for removing foreign matter using the above-mentioned visual sensor protective cover, comprising the following steps:

[0022] When the visual sensor does not need to collect images, the cover is closed to cover the window assembly. At the same time, the air pipe is connected to the air source and filled with high-pressure gas. The gas enters the acute-angle cavity and is squeezed and pressurized by the acute-angle cavity. The gas is then directed to the surface of the protective glass and finally discharged from the cavity along the through groove.

[0023] When the visual sensor needs to collect images, the cover is opened to reveal the window assembly; at the same time, the air pipe is disconnected from the air source and no air is supplied;

[0024] Visual sensors are used for image acquisition.

[0025] This design has the following features:

[0026] There are three main factors that affect the airflow's ability to clean foreign matter from the protective glass surface: ① the amount of gas reaching the glass surface, ② the gas flow rate, and ③ the air pressure. This invention features a unique airway structure with a triangular structure on one side and a double-slope stepped structure on the other. This design improves the amount of gas reaching the glass surface, the gas flow rate, and the air pressure. Specifically:

[0027] ① Gas volume. In this design, after the cover is closed, the protective glass is within the cavity. Once gas enters, there is virtually no gas loss. Experiments have shown that over 95% of the gas reaches the protective glass surface. In contrast, in patent document CN210005424U, a sensor protection device, mentioned in the background technology, the gas reaches the protective glass surface in a completely unenclosed space, resulting in significant gas loss and a significant reduction (approximately 60%) in the amount of gas that ultimately reaches the protective glass.

[0028] ② Gas flow rate. Gas is a fluid substance. Effective airway confinement not only prevents it from dispersing but also increases its flow rate. In this design, the first slope 12 and one surface of the triangular groove 32 form an acute-angle cavity (pointed-angle cavity). When gas enters through the air hole, it first accumulates rapidly in the acute-angle cavity. Once the gas fills the acute-angle cavity, it is squeezed by the acute-angle cavity and flows downward at a faster rate.

[0029] One side of the airway is a triangular structure, and the other side is a double slope (the first slope and the second slope from top to bottom). The angle β between the first slope 12 and the plane where the protective glass is located is 5° to 20°, and more preferably less than 10°. Experiments have shown that this angle is the angle at which gas flows most easily downward. The angle of the second slope 11 is greater than that of the first slope. The second slope 11 and the other surface of the triangular groove 32 are both guide surfaces. The purpose of their design is to allow the gas to quickly descend from the first slope and then move in the direction that is most likely to blow toward the protective glass. The wind knife adheres to the protective glass and moves around, forming a strong wind knife, which has a better effect in removing foreign matter. In addition, the minimum height difference H between the second slope 11 and the plane where the protective glass is located is designed to be 0.1 to 0.5 cm, which can make the airflow have a more diving effect.

[0030] Without the first slope, the airflow would slow down. Without the second slope, the air would have to turn at a right angle before reaching the glass surface, slowing the flow rate. Experiments have shown that with this design, the airflow rate can meet the requirements for lens surface cleaning.

[0031] ③ Air pressure, atmospheric pressure P = 0.1Mpa. In this design, the air pipe is connected to a vacuum compressor, and the gas pressure in the air pipe is P1 = 0.7 ~ 1.3MPa (P1>P). The second through hole and the triangular groove are connected to the external atmospheric pressure, and the pressure in the airway is P. After the gas enters the airway, the pressure in the second through hole and the cavity increases, and the gas flows to the glass surface. The gas reaching the glass surface is still a high-pressure gas. The high-pressure gas is high-pressure gas throughout the entire process from the airway to the glass surface, and then discharged from the cavity to the atmospheric pressure. The double-edged wind knife formed is sharper and has a better cleaning effect. However, in a sensor protection device such as the patent document CN210005424U, the gas has entered the atmospheric pressure after being discharged through the air outlet. The gas is scattered, the gas volume is small, the gas flow rate is low, and the gas reaching the glass surface is already at atmospheric pressure P. The cleaning ability is weak and the cleaning range is limited.

[0032] The triangular groove, the first slope and the second slope in the window assembly complement each other and together form a unique airway structure. The air intake of the air ducts on both sides of the airway can form a "double-edged wind knife". After the air enters the air duct, the gas first accumulates rapidly in the acute-angle cavity formed by the opening end of the triangular groove and the first slope. After the gas fills the cavity, it will be squeezed by the acute-angle cavity, and the cold air flows downward at a faster speed. The wind knife is faster and more powerful, diving towards the protective glass along the first slope, scraping the protective glass from top to bottom with stronger scraping force, and finally discharged along the narrow gap below to achieve the removal of foreign objects with strong adhesion.

[0033] During the time when the visual sensor is not taking images, the "double-edged air knife" continuously "scrapes" the surface of the protective glass, which can quickly and effectively remove grease, stubborn stains and other foreign matter on the surface of the protective glass, with fast cleaning speed and good effect.

[0034] The protective cover provided by this design can be used with various visual detection sensors and is easy to install. It can prevent foreign matter from adhering to the visual sensor window, affecting the image acquisition effect, and reduce equipment maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the decomposition structure of the window component;

[0036] Figure 2 This is a diagram of the window component decomposition structure (from another angle);

[0037] Figure 3 It is a schematic diagram of the cross-sectional structure after the cover body covers the window assembly;

[0038] Figure 4 It is a partial enlarged schematic diagram of the triangular groove, the first slope surface, and the second slope surface;

[0039] Figure 5 Schematic diagram of the overall structure of the protective cover;

[0040] Figure 6 Schematic diagram of the overall structure of the protective cover (from another angle);

[0041] Figure 7 Schematic diagram of the angles between the first slope, the second slope and the plane where the protective glass is located. DETAILED DESCRIPTION

[0042] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] A visual sensor protective cover with a foreign matter removal function, comprising a window assembly and a cover body 6;

[0044] like Figure 1-2As shown, the window assembly includes a window body 1 and a connector 3. The window body 1 is fixed to the front end of the camera lens of the visual sensor, and a protective glass 2 is installed in the middle area of ​​the window body 1. The protective glass is located slightly lower than the front wall of the window body after installation. The connector 3 is in the shape of a U-shaped or ring-shaped member so as not to obstruct the camera's field of view. The connector 3 is fixed to the front wall of the window body and has a triangular groove 32 on one side and a through groove 34 on the opposite side. The through groove 34 forms a narrow gap between the connector 3 and the window body 1. The opening of the triangular groove 32 faces the protective glass, and through holes are provided on the side walls of the connector 3 at both ends of the triangular groove 32, corresponding to the ends of the triangular groove 32, for connecting to the air pipe 8.

[0045] The cover 6 is provided at the front end of the window assembly, which can block or reveal the window assembly; when the cover 6 blocks the window body 1, a cavity is formed between the window body 1, the connector 3, and the cover 6, and the air pipe is filled with high-pressure gas (0.7-1.3 MPa) at this time;

[0046] like Figure 3-4 As shown (In order to facilitate the display of the structure inside the cavity, Figure 3 、 4 (The rear outer wall of the middle window body is shown with a dotted line), and the front wall of the window body 1 is provided with a first slope 12 and a second slope 11 connected in sequence at the position corresponding to the triangular groove. The first slope 12 and one surface of the triangular groove 32 form an acute-angle cavity, and the second slope 11 and the other surface of the triangular groove 32 are both guide surfaces, which can guide the gas to the surface of the protective glass after the gas enters the acute-angle cavity through the air pipe 8 and is squeezed and pressurized by the acute-angle cavity, and finally the gas is discharged from the cavity along the through groove 34.

[0047] The triangular groove, the first slope 12 and the second slope 11 in the window assembly of this design form a unique airway structure. The air intake on both sides can form a "double-edged wind knife". When the visual sensor is not taking pictures, the "double-edged wind knife" continuously "scrapes" the surface of the protective glass, which can quickly and effectively remove grease, stubborn stains and other foreign matter on the surface of the protective glass, with fast cleaning speed and good cleaning effect.

[0048] When the gas fills the sharp-angled cavity, it will be squeezed, and the cold air will flow downward at a faster speed. The wind knife will be faster and more powerful, diving towards the protective glass, and finally discharged along the narrow gap below.

[0049] Compared with the prior art, which blows air directly onto the surface of the object to be tested, the gas scatters and the force is weak, which is not enough to remove stubborn foreign matter. In the present invention, the gas is in the cavity and is not easy to scatter, and the wind knife is sharper and stronger.

[0050] In order to make it easier for the gas to be discharged along the airway, the cross section of the triangular groove 32 is a right triangle or an obtuse triangle, and the smallest angle of the triangle is 10° to 40°. The surface where the angle (acute angle) is located is opposite to the second slope surface, and both are guide surfaces. Together, they guide the gas to the protective glass. In this embodiment, Figure 3 As shown, the cross section of the triangular groove is a right triangle, with an upper angle of 60° and a lower angle of 30°.

[0051] The width of the triangular groove 32 is equal to or greater than the width of the cover glass 2 .

[0052] As a preferred embodiment, Figure 7 As shown, the angle β between the first slope 12 and the plane of the protective glass is between 5° and 20°, and more preferably less than 10°. This angle is the angle at which gas flows most easily downward, and the slope allows gas to descend rapidly. In this embodiment, β = 8°, resulting in an acute-angle cavity angle of 60 + 8 = 68°.

[0053] The angle α between the second slope 11 and the plane of the protective glass is set at 20° to 60°. The design objective of the second slope 11 (where the angle α is acute) is to ensure that both the second slope 11 and the other side of the triangular groove 32 act as flow guides. This allows the air to rapidly descend from the first slope and then move in the direction most likely to reach the protective glass. The air knife then moves in close contact with the protective glass, creating a powerful air knife that effectively removes foreign matter. In this embodiment, α = 25°.

[0054] like Figure 4 As shown, the minimum height difference H between the second slope 11 and the plane where the protective glass is located is 0.1 to 0.5 cm. The design height difference of 0.1 to 0.5 cm can make the airflow have a more dive effect.

[0055] When in use, the method for removing foreign matter using the above-mentioned visual sensor protective cover includes the following steps:

[0056] When the visual sensor does not need to capture images, the cover 6 is closed to cover the window assembly. At the same time, the air pipe 8 is connected to the air source and filled with high-pressure gas. The gas enters the acute-angle cavity and is squeezed and pressurized by the acute-angle cavity. The gas is then directed to the protective glass surface and finally discharged from the cavity along the through groove 34.

[0057] When the visual sensor needs to collect images, the cover 6 is opened to expose the window assembly; at the same time, the air pipe 8 is disconnected from the air source and no air is taken in;

[0058] Visual sensors are used for image acquisition.

[0059] In specific implementation, this solution does not limit the opening and closing method of the cover 6. It only needs to close the cover 6 when the sensor does not need to collect images, and open the cover 6 when the visual sensor needs to collect images. In this embodiment, two cover installation methods are provided:

[0060] Method 1:

[0061] The cover body 6 is connected to a motor, and the motor can control the cover body 6 to move horizontally at the front end of the window assembly (connecting piece) to open and close left and right.

[0062] Method 2:

[0063] like Figure 5-6 As shown, the cover body 6 is connected to the cylinder 5, and the cylinder 5 can control the cover body 6 to rotate at the front end of the window assembly (connecting piece) to achieve up and down opening and closing.

[0064] Specifically, the cylinder 5 is mounted on the support base 4 and is controlled by the first solenoid valve 7. The support base 4 is fixed to the surface of the visual sensor housing, and the cover 6 is hinged to the front end of the support base 4. The piston rod of the cylinder 5 is hinged to the cover 6. The first solenoid valve 7 controls the piston rod in the cylinder 5 to retract backward, thereby pulling the cover 6 open and revealing the window assembly; alternatively, the first solenoid valve 7 controls the piston rod in the cylinder 5 to advance forward, pushing the cover 6 downward to close and cover the window assembly.

[0065] The air pipe 8 is controlled by the second solenoid valve 9 , and the second solenoid valve controls the air intake of the air pipe 8 .

[0066] More specifically, the cylinder is a double-acting cylinder, the first solenoid valve is a two-position four-way solenoid valve, and the second solenoid valve is a two-position three-way solenoid valve.

[0067] When this method is used, the process of foreign body removal is as follows:

[0068] When the visual sensor does not need to capture images, the controller sends a first signal to both the first solenoid valve and the second solenoid valve. The first solenoid valve controls the piston rod in the cylinder 5 to advance forward, pushing the cover 6 downward to close and cover the connector 3. At the same time, the second solenoid valve controls the air pipe 8 to continuously intake air. The air enters the acute-angle cavity and is squeezed and pressurized by the acute-angle cavity. The guide surface (the other surface of the second slope 11 and the triangular groove 32) guides the air to the surface of the protective glass. The air scrapes away foreign matter attached to the surface of the protective glass. Finally, the air is discharged from the cavity along the narrow gap formed by the through groove 34 and the front wall of the window body.

[0069] When the visual sensor needs to capture images, the controller sends a second signal to both the first solenoid valve and the second solenoid valve. The first solenoid valve controls the piston rod in the cylinder 5 to retract backward, thereby pulling the cover 6 open. At the same time, the second solenoid valve controls the air pipe 8 to stop taking in air.

[0070] Visual sensors are used for image acquisition.

[0071] The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. The foregoing descriptions are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been chosen and described in order to explain the specific principles of the invention and their practical application, thereby enabling others skilled in the art to make and utilize the various exemplary embodiments of the invention and various alternatives and modifications thereof. The scope of the invention is intended to be defined by the appended claims and their equivalents.

Claims

1. A visual sensor protective cover with a foreign body removal function, characterized in that: It includes a window assembly and a cover body (6); The window assembly comprises a window body (1) and a connecting piece (3); the window body (1) is fixed to the front end of the camera lens of the visual sensor, and a protective glass (2) is installed in the middle area of ​​the window body (1); the plane where the protective glass is installed is slightly lower than the front wall of the window body; the connecting piece (3) is in the shape of a circle or a ring and does not block the camera field of view; the connecting piece (3) is fixed to the front wall of the window body, and a triangular groove (32) is provided on one side thereof, and a through groove (34) is provided on the opposite side thereof, and the through groove (34) can form a narrow gap between the connecting piece (3) and the window body (1); the opening of the triangular groove (32) faces the protective glass, and through holes are provided on the side walls of the connecting piece (3) at both ends of the triangular groove (32) corresponding to the ends thereof for connecting the air pipe (8); The cover (6) is arranged at the front end of the window assembly, and can block or leak out the window assembly; when the cover (6) blocks the window assembly, a cavity is formed between the window body (1), the connecting piece (3), and the cover (6), and the air pipe is filled with high-pressure gas at this time; A first slope surface (12) and a second slope surface (11) connected in sequence are provided on the front wall of the window body (1) at a position corresponding to the triangular groove. The first slope surface (12) and one surface of the triangular groove (32) form an acute-angle cavity. The second slope surface (11) and the other surface of the triangular groove (32) are both guide surfaces. After the gas enters the acute-angle cavity through the air pipe (8) and is squeezed and pressurized by the acute-angle cavity, the gas is guided to the surface of the protective glass. Finally, the gas is discharged from the cavity along the through groove (34).

2. The visual sensor protective cover with foreign matter removal function as claimed in claim 1, characterized in that: The cross section of the triangular groove (32) is a right triangle or an obtuse triangle, the smallest angle of the triangle is 10° to 40°, the surface where the angle is located is opposite to the second slope surface, and both are diversion surfaces.

3. The visual sensor protective cover with foreign matter removal function as claimed in claim 1, characterized in that: The width of the triangular groove (32) is equal to or greater than the width of the protective glass (2).

4. The visual sensor protective cover with foreign matter removal function as claimed in claim 1, characterized in that: The included angle β between the first slope surface (12) and the plane where the protective glass is located is 5° to 20°; the included angle α between the second slope surface (11) and the plane where the protective glass is located is 20° to 60°.

5. The visual sensor protective cover with foreign matter removal function as claimed in claim 1, characterized in that: The minimum height difference H between the second slope (11) and the plane where the protective glass is located is 0.1 to 0.5 cm.

6. The visual sensor protective cover with foreign matter removal function as claimed in claim 1, characterized in that: The cover body (6) is connected to the cylinder (5), and the cylinder (5) can control the cover body (6) to rotate at the front end of the window assembly to achieve up and down opening and closing.

7. The visual sensor protective cover with foreign matter removal function as claimed in claim 6, characterized in that: The cylinder (5) is mounted on a support seat (4) and is controlled by a first solenoid valve (7). The support seat (4) is fixed on the surface of the visual sensor housing, and the cover (6) is hinged to the front end of the support seat (4). The piston rod of the cylinder (5) is hinged to the cover (6). The first solenoid valve (7) controls the piston rod in the cylinder (5) to retract backward, thereby pulling the cover (6) open. Alternatively, the first solenoid valve (7) controls the piston rod in the cylinder (5) to advance forward, pushing the cover (6) downward to close and cover the connecting member (3). The air pipe (8) is controlled by a second electromagnetic valve (9), and the second electromagnetic valve controls the air intake of the air pipe (8).

8. The visual sensor protective cover with foreign matter removal function as claimed in claim 7, characterized in that: The cylinder is a double-acting cylinder, the first solenoid valve is a two-position four-way solenoid valve, and the second solenoid valve is a two-position three-way solenoid valve.

9. The visual sensor protective cover with foreign matter removal function as claimed in claim 1, characterized in that: The cover body (6) is connected to a motor, and the motor can control the cover body (6) to move horizontally at the front end of the window assembly to achieve left and right opening and closing.

10. A method for removing foreign matter using the visual sensor protective cover according to any one of claims 1 to 9, characterized in that: The following steps are involved: When the visual sensor does not need to collect images, the cover (6) is closed to cover the window assembly. At the same time, the air pipe (8) is connected to the air source and filled with high-pressure gas. The gas enters the acute-angle cavity and is squeezed and pressurized by the acute-angle cavity, and then the gas is directed to the protective glass surface. Finally, the gas is discharged from the cavity along the through groove (34); When the visual sensor needs to collect images, the cover (6) is opened to expose the window assembly; at the same time, the air pipe (8) is disconnected from the air source and no air is taken in; Visual sensors are used for image acquisition.

Images