Lens unit for hole inspection

Abstract

The lens unit for hole inspection includes: a cylindrical outer tube; a cylindrical inner tube inserted through the inside of the outer tube; an objective lens disposed in the tip of the inner tube; an interface part supporting a base end part of the outer tube and a base end part of the inner tube and having a camera mounted thereon, the camera shooting an inside of the hole via an objective lens; a cylindrical light guide tube disposed between the outer tube and the inner tube so as to be surrounded by the tip of the outer tube and the tip of the inner tube; and a plurality of cannonball-type light-emitting diodes disposed inside the outer tube and around the inner tube so as to face each of the end portions of the light guide tube on the interface portion side.

Description

Technical Field

[0001] The present disclosure relates to a hole inspection lens unit for inspecting the inside of a hole formed in a workpiece. Background Art

[0002] In the past, there is a known device for inspecting the inside of a hole, which includes an inspection head and a manipulator, and the manipulator moves the inspection head so that the inspection head is at a specified distance from the opening of the hole of the workpiece (for example, refer to patent document 1). The inspection head of the device for inspecting the inside of a hole includes: a camera for photographing the hole of the workpiece; a wide-angle lens having an optical axis parallel to the axis of the hole of the workpiece; a relay lens composed of a combination of multiple high-precision lenses; and a half-reflecting mirror for refracting light from a point illumination (light source) and irradiating it to the hole. The light from the point illumination is refracted by the half-reflecting mirror and passes through the relay lens and the wide-angle lens, and is uniformly irradiated onto the inner surface of the hole. The reflected light from the hole is incident on the camera through the wide-angle lens, the relay lens, and the half-reflecting mirror. Then, the camera photographs the inside of the hole from a position at a specified distance from the opening of the hole on the outside of the hole.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-036203 Summary of the invention

[0006] Problems to be solved by the invention

[0007] As described above, when photographing the inside of a hole with the camera away from the opening of the hole, it is necessary to ensure uniform illumination throughout the entire hole using an illumination device. In order to ensure illumination inside the hole, it is also possible to consider using a light source including, for example, an optical fiber as an illumination device, but since light has a strong linear propagation property, light streaks will be included in the image photographed by the camera.

[0008] Therefore, a main object of the present disclosure is to provide a hole inspection lens unit that can ensure uniform illumination inside a hole when photographing the inside of a hole of a workpiece using a camera, thereby reducing noise in an image photographed by the camera.

[0009] Technical solutions to problems

[0010] The hole inspection lens unit disclosed in the present invention is used to inspect the inside of a hole formed on a workpiece, and includes: a cylindrical outer tube; a cylindrical inner tube, which is inserted through the inside of the outer tube; an objective lens, which is arranged in the top end of the inner tube; an interface portion, which supports the base end portion of the outer tube and the base end portion of the inner tube and is equipped with a camera, and the camera photographs the inside of the hole through the objective lens; a cylindrical light guide tube, which is arranged between the outer tube and the inner tube in a manner that is surrounded by the top end portion of the outer tube and surrounds the top end portion of the inner tube; and a plurality of cannonball-shaped light emitting diodes, which are arranged in the inside of the outer tube and around the inner tube in a manner that they are respectively opposite to the ends of one side of the interface portion of the light guide tube.

[0011] When the hole inspection lens unit disclosed in the present invention is used to photograph the inside of a hole formed in a workpiece with a camera, the lens unit with the camera mounted on the mount portion is made stationary in such a manner that the objective lens is located above the hole. Then, each cannonball-shaped light emitting diode is made to emit light. The cannonball-shaped light emitting diode has excellent light-gathering properties, and the light emitted from each cannonball-shaped light emitting diode is diffused into the inside of the hole through a cylindrical light guide and irradiates. Thus, when the inside of the hole of the workpiece is photographed with a camera, uniform illumination can be ensured inside the hole, thereby reducing the noise of the image photographed by the camera. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic configuration diagram showing a hole inspection system to which the hole inspection lens unit of the present disclosure is applied.

[0013] Figure 2 2 is a cross-sectional view showing a hole inspection lens unit according to the present disclosure. DETAILED DESCRIPTION

[0014] Next, a mode for carrying out the invention disclosed herein will be described with reference to the drawings.

[0015] Figure 1 1 is a schematic structural diagram showing a hole inspection system 1 to which a hole inspection lens unit (hereinafter referred to as "lens unit") 20 of the present disclosure is applied. The hole inspection system 1 shown in the figure is a system for inspecting the inside of a hole H formed on a workpiece W such as a transmission housing. The hole H to be inspected may be a threaded hole or a non-threaded hole, a through hole or a non-through hole. In addition, the workpiece W is not limited to the transmission housing.

[0016] like Figure 1As shown, the hole inspection system 1 includes: a system control device 2; a plurality of manipulators 3; a plurality of manipulator control devices 4, each connected to the system control device 2 and controlling the corresponding manipulators 3; and an inspection processing device 5, connected to the system control device 2. The system control device 2 is a device including a computer having a CPU (Central Processing Unit), a ROM (Read-Only Memory), a RAM (Random Access Memory), etc., and exchanges signals (information) with the plurality of manipulator control devices 4 and the inspection processing device 5 to control the hole inspection system 1 in a unified manner. Each manipulator 3 is a robot arm capable of holding and moving the imaging tool 10 including the lens unit 20 and the camera 30. In addition, each manipulator control device 4 is a device including a computer having a CPU, a ROM, a RAM, etc., and controls the corresponding manipulator 3 according to a predetermined control sequence to move the imaging tool 10 to an inspection operation position above a certain distance from the target hole H.

[0017] The inspection processing device 5 is a computer having a CPU, ROM, RAM, etc. The camera 30 of the imaging tool 10 is connected to the inspection processing device 5 via a connector, a cable, etc. provided on the manipulator 3. Furthermore, an inspection program is installed in the inspection processing device 5, and the inspection program is used to inspect the state of the inside of the hole H based on the image (image data) of the inside of the hole H photographed by the camera 30. The inspection program (software) cooperates with the hardware such as the CPU, ROM, and RAM of the inspection processing device 5, and realizes, for example, a neural network that determines (diagnoses) whether the state of the inside of the hole H is good or not based on the image photographed by the camera 30.

[0018] Figure 2 2 is a longitudinal sectional view showing the lens unit 20. As shown in the figure, the lens unit 20 includes an outer tube 21, an inner tube 22, an objective lens unit 23, a plurality of relay lenses 24, an interface unit 25 to which a camera 30 is mounted, a holder 26, a light guide 27, and a plurality of (for example, 6 in this embodiment) cannonball-shaped light emitting diodes 28.

[0019] The outer tube 21 is formed into a cylindrical shape by a light-shielding material such as metal, and the top end of the outer tube 21 is formed to be tapered. The inner tube 22 is formed into a cylindrical shape by a light-shielding material such as metal (e.g., stainless steel), and the outer diameter thereof is smaller than the inner diameter of the outer tube 21. The inner tube 22 is coaxially inserted into the interior of the outer tube 21 and fixed to the base end of the outer tube 21 via a retainer 26. The objective lens section 23 has a wide-angle lens 23w, and is arranged (fixed) in the top end of the inner tube 22. A plurality of relay lenses 24 are arranged at intervals inside the inner tube 22 in such a manner as to relay the image from the wide-angle lens 23w to the camera 30 mounted on the interface section 25.

[0020] The interface portion 25 is fixed to the holder 26, and the base end of the outer tube 21 and the base end of the inner tube 22 are supported via the holder 26. In addition, an external thread 25t of the C-type mount standard is formed on the outer peripheral surface of the interface portion 25. Thus, various industrial cameras of the C-type mount standard can be mounted on the interface portion 25. In addition, an industrial camera of the CS-type mount standard can also be mounted on the interface portion 25 via an adapter.

[0021] The light guide tube 27 is formed into a relatively short cylindrical shape by glass, quartz, etc., and its outer diameter is slightly smaller than the inner diameter of the outer tube 21 and its inner diameter is slightly larger than the outer diameter of the inner tube 22. The light guide tube 27 is fitted in the top end of the outer tube 21, and the top end of the inner tube 22 is fitted inside the light guide tube 27. Thus, the light guide tube 27 is arranged between the outer tube 21 and the inner tube 22 in a manner surrounded by the top end of the outer tube 21 and surrounding the top end of the inner tube 22. In addition, a plurality of cannonball-shaped light emitting diodes 28 are arranged at intervals (equal intervals) inside the outer tube 21 and around the inner tube 22 in a manner that they are respectively opposed to (abutted against) the end of the interface portion 25 of the light guide tube 27. It should be noted that the cables (not shown) connected to each cannonball-shaped light emitting diode 28 are led out to the outside of the outer tube 21 through the space between the outer tube 21 and the inner tube 22, and are connected to a lighting power source (not shown) through a connector.

[0022] When the camera 30 is used to photograph the inside of the hole H formed on the workpiece W using the lens unit 20 constructed as described above, the robot 3 is used to move the photographing tool 10, that is, the lens unit 20 with the camera 30 mounted on the interface 25, so that the objective lens 23 (wide-angle lens 23w) is located at a position above the hole H at a predetermined distance, and the lens unit 20 is stationary at the inspection operation position. Then, each cannonball-shaped light-emitting diode 28 is made to emit light. The cannonball-shaped light-emitting diode 28 has excellent light-gathering properties, and the light emitted from each cannonball-shaped light-emitting diode 28 is diffused and irradiated into the inside of the hole H via the cylindrical light guide 27. As a result, when the camera 30 is used to photograph the inside of the hole H of the workpiece W, uniform illumination can be ensured inside the hole H, so that noise such as light streaks in the image photographed by the camera 30 can be very well reduced.

[0023] In addition, an external thread 25t of a C-type interface standard, which is a typical standard for industrial cameras, is formed on the interface portion 25 of the lens unit 20. As a result, a plurality of industrial cameras having different specifications such as the number of pixels can be mounted on the interface portion 25, so that the inside of the hole H can be photographed using a camera 30 suitable for the hole H to be photographed. In addition, the objective lens portion 23 of the lens unit 20 includes a wide-angle lens 23w, and a plurality of relay lenses 24 are arranged inside the inner tube 22. As a result, the entire inside of the hole H can be focused. In addition, by arranging a plurality of relay lenses 24 inside the inner tube 22, the axial length of the lens unit 20 can be determined according to the shape of the workpiece W, for example, the axial length of the lens unit 20 for photographing the inside of the hole H formed at the bottom of the workpiece W can be extended. However, depending on the required axial length of the lens unit 20, a single relay lens 24 can be arranged in the inner tube 22, or the relay lens 24 can be omitted.

[0024] As described above, the hole inspection lens unit disclosed in the present invention is a hole inspection lens unit (20) for inspecting the inside of a hole (H) formed on a workpiece (W), and comprises: a cylindrical outer tube (21); a cylindrical inner tube (22) which is inserted through the inside of the outer tube (21); an objective lens (23, 23w) which is arranged at the top end of the inner tube (22); an interface portion (25) which supports the base end of the outer tube (21) and the base end of the inner tube (22) and is equipped with a camera (30), the interface portion (25) A camera (30) photographs the interior of the hole (H) via the objective lens (23, 23w); a cylindrical light guide tube (27) is arranged between the outer tube (21) and the inner tube (22) in a manner that it is surrounded by the top end of the outer tube (21) and surrounds the top end of the inner tube (22); and a plurality of shell-shaped light emitting diodes (28) are arranged inside the outer tube (21) and around the inner tube (22) in a manner that they are respectively opposite to the ends of one side of the interface portion (25) of the light guide tube (27).

[0025] When the hole inspection lens unit disclosed in the present invention is used to photograph the inside of a hole formed on a workpiece with a camera, the lens unit with the camera mounted on the interface is made stationary in a manner that the objective lens is located above the hole. Then, each cannonball-shaped light emitting diode is made to emit light. The cannonball-shaped light emitting diode has excellent light-gathering properties, and the light emitted from each cannonball-shaped light emitting diode is diffused into the inside of the hole through a cylindrical light guide and irradiates. Thus, when the inside of the hole of the workpiece is photographed with a camera, uniform illumination can be ensured inside the hole, thereby reducing the noise of the image photographed by the camera.

[0026] In addition, an external thread (25t) conforming to the C-type interface standard can be formed on the interface portion (25).

[0027] Thus, a plurality of cameras having different specifications such as the number of pixels can be mounted on the interface portion, and therefore the interior of the hole can be photographed using a camera suitable for the hole to be photographed.

[0028] Furthermore, the objective lens may be a wide-angle lens (23w), and at least one relay lens (24) may be arranged inside the inner tube (22).

[0029] This allows the entire interior of the hole to be in focus, and the axial length of the lens unit to be determined in accordance with the shape of the workpiece and the like.

[0030] In addition, the plurality of shell-shaped light emitting diodes (28) can respectively abut against the end portion of the interface portion (25) of the light guide tube (27).

[0031] It should be noted that the invention disclosed herein is not limited to the above-mentioned embodiments, and various modifications can be made within the scope of the present disclosure. Moreover, the above-mentioned embodiments are only a specific mode of the invention described in the invention content, and do not limit the invention elements described in the invention content.

[0032] Industrial Applicability

[0033] The disclosed invention is very useful in manufacturing for inspecting the interior of a hole formed in a workpiece.

Claims

1. A hole inspection lens unit for inspecting the inside of a hole formed in a workpiece, wherein: have: A cylindrical outer tube; A cylindrical inner tube is inserted through the outer tube; an objective lens disposed in the top end of the inner tube; an interface portion that supports the base end portion of the outer tube and the base end portion of the inner tube and is equipped with a camera that photographs the interior of the hole via the objective lens; a cylindrical light guide tube disposed between the outer tube and the inner tube so as to be surrounded by the distal end portion of the outer tube and surround the distal end portion of the inner tube; and A plurality of cannonball-shaped light emitting diodes are disposed inside the outer tube and around the inner tube so as to face the end portions of the light guide tube on the interface portion side.

2. The hole inspection lens unit according to claim 1, wherein: An external thread conforming to the C-type interface standard is formed in the interface portion.

3. The hole inspection lens unit according to claim 1, wherein: The objective lens is a wide-angle lens, and at least one relay lens is disposed inside the inner tube.

4. The hole inspection lens unit according to any one of claims 1 to 3, wherein: The plurality of cannonball-shaped light emitting diodes are respectively in contact with the end portion of the light guide tube on the interface portion side.

Images