TWI825932B - Mechanism and method for detection of internal thread defects - Google Patents

Abstract

A mechanism and a method for detection of internal thread defects are provided. The mechanism includes a bracket unit, a rotary unit, a gripping unit, and a camera module, wherein the position of a focal plane is changed by the shift operation of a moving lens of the camera module, so as to obtain a clearer image from the inner thread of a nut to detect smaller size defects.

Description

Mechanism and method for internal thread defect detection

The present invention relates to a detection mechanism and method, in particular to a mechanism and method for detecting internal thread defects.

Screws, bolts, nuts, screws, etc. are common fixing elements, which use the design of threads to achieve the purpose of being combined with each other or integrated into items. When there are defects in the threads, such as helical threads, irregular threads, etc., it will lead to poor threading, jamming, or loss of threading function. Therefore, when components such as screws, bolts, nuts, and screws are manufactured, they need to go through a thread inspection process to eliminate defective components.

Currently common thread inspections, for example, the automatic nut internal thread quality inspection equipment patented No. I719821, use the nut to be tested to screw into the GO to NOGO end of the tapered thread gauge at a certain torque to determine the accuracy level of the thread. , converting manual tooth gauge geometry detection into automatic power detection to achieve automated detection effects; the internal thread detection and screening machine of Patent No. M576920 uses a detection component fixed on the buffer and includes a detection tooth gauge coaxially arranged with the transmission shaft , provides an internal thread inspection and screening machine that can provide buffering function and occupy less space; the nut screening machine with patent No. M299294 is stably transported from the inside and outside through the first and second adjustment seats of the side inspection conveyor. The image sensor CCD of the diameter and thread detection device captures the image for detection; the detection device and screening machine of Patent No. M575098 use the processing device to compare the difference between at least one image to be analyzed and at least one reference image, or compare The difference between several images to be analyzed of the same part to be tested, and to determine whether the screw hole of the part to be tested meets the requirements; the optical image thread detection system and method of Patent No. I670487 uses a laser projection machine to project linear radar Emits light beams on a plurality of threads to be tested and compares them with the reference thread laser pattern, reference peak pattern, reference root pattern, reference horizontal spacing and reference vertical spacing stored in the electronic device to determine the plurality of threads to be tested. Are the threads defective?

However, the above-mentioned thread inspection can only detect external thread defects or appearance defects. The internal thread defect detection technology is not yet mature, and it is difficult to detect subtle defects in internal threads or distinguish the type of defects.

Therefore, in order to overcome the shortcomings and deficiencies in the prior art, it is necessary for the present invention to provide an improved mechanism and method for detecting internal thread defects, so as to solve the problems existing in the above conventional technology.

The main purpose of the present invention is to provide a mechanism and method for internal thread defect detection, which changes the position of the focal plane through the tilt-shift operation of the tilt-shift lens, so as to obtain a higher-definition photographic image of the internal thread of the nut. It also solves the problem that ordinary lenses cannot capture the complete internal thread image of the nut and detects smaller-sized defects.

In order to achieve the above purpose, the present invention provides a mechanism for detecting internal thread defects. The mechanism includes a bracket unit, a rotation unit, a clamping unit and a photography module; the bracket unit includes a base and a stand. , the upright frame is arranged on the base; the rotating unit is arranged on the base, wherein the rotating unit includes a rotating table and a driving member, the driving member drives the rotating table to rotate along a rotating axis; the gripping unit Disposed on the rotating stage, the clamping unit includes two clamping arms. The clamping arms are configured to jointly clamp a piece to be tested. The clamping arms are driven by the rotating table to clamp the piece to be tested. Rotates along a central axis, and the central axis is coaxial with the rotation axis; the photography module is arranged on the upright stand and is spaced a distance from the gripping unit, and the photography module includes a tilt-shift lens and a camera, wherein the photography module The tilt-shift lens is configured to be able to adjust an angle of a lens plane of the tilt-shift lens so that the lens plane intersects a shooting plane of the device under test and an imaging plane of the camera to focus on the internal threads of the device under test and take images.

In one embodiment of the present invention, the clamping unit further includes two clamping ends. The clamping ends are concave and respectively formed on the clamping arms. The clamping ends are configured to abut against the clamping arms. Two opposite surfaces of the part to be tested.

In one embodiment of the present invention, the rotary table has a tube body, an extension platform, a pulley and a belt. The tube body penetrates the base, the extension platform is arranged on the upper edge of the tube body, and the pulley is arranged on At the bottom of the tube body, the belt is sleeved on the pulley and configured to transmit the power of the driving member.

In one embodiment of the present invention, the rotating unit further includes a sensing piece and a sensor. The sensing piece is fixed under the pulley. The sensor is disposed on the base, and the sensor is configured as The position of the sensing piece is sensed to determine whether the state of the rotary table is rotating or stopped.

In one embodiment of the present invention, the clamping ends are positioned opposite to a through hole of the tube body, and the through hole is configured to allow the object to be tested to pass.

In one embodiment of the present invention, the gripping unit further includes a cylinder clamp, the clamp arms are provided on the cylinder clamp, the cylinder clamp is disposed on the rotating table and configured to adjust the clamp arms opening and closing.

In one embodiment of the present invention, the photography module further includes an annular light source, and the tilt-shift lens is disposed in the annular light source.

In order to achieve the above purpose, the present invention provides a method for internal thread defect detection. The method includes a preparation step, a feeding step and an imaging step; in the preparation step, a bracket unit and a rotation unit are prepared. , a clamping unit and a photography module, the rotating unit is arranged on a base of the bracket unit, the clamping unit is arranged on a rotating table of the rotating unit, and the photographing module is arranged on a base of the bracket unit On the upright frame and at a distance from the clamping unit; in the feeding step, a piece to be tested is placed between the two clamping arms of the clamping unit, so that the clamping arms jointly clamp the piece to be tested ; In the imaging step, a tilt-shift lens of the photography module is used to adjust an angle of a lens plane of the tilt-shift lens so that the lens plane is connected to a photography plane of the device to be tested and the lens plane of the photography module An imaging plane of a camera intersects to focus on the internal thread of the part to be tested and capture an image.

In one embodiment of the present invention, in the imaging step, the photography module captures the image of the object to be tested and uses a driving member of the rotation unit to drive the rotation stage to rotate along a rotation axis, wherein the The clamping arm is driven by the rotating stage so that the object to be tested is clamped and rotates along a central axis, and the central axis is coaxial with the rotation axis.

In one embodiment of the present invention, after the imaging step, the method for detecting internal thread defects further includes a discharging step, in which the piece to be tested is withdrawn from the clamping arms, and the piece to be tested is The imaging results are used to classify the object under test passing through a through hole of a tube body of the rotary stage.

As mentioned above, by changing the position of the focal plane through the tilt-shift operation of the tilt-shift lens, a higher-definition photographed image of the internal thread of the object to be tested can be obtained, so that defects in internal thread detection are not limited to those occurring on the surface. The tooth valley or tooth peak can also solve the problem that ordinary lenses cannot capture the complete internal thread image of the nut and detect smaller-sized defects. In addition, the rotation axis of the extension platform rotates coaxially with the central axis of the object to be tested, so that the object to be tested will not be deflected when being rotated by the extension platform. Furthermore, the hollow design of the pipe body allows the parts to be tested after inspection and judgment to be sorted and collected in the area below the pipe body directly through the through hole. Therefore, it can cooperate with the actual production line to carry out first feeding, last inspection and then out. A coherent process of materials to reduce inspection time and increase production efficiency.

In order to make the above and other objects, features, and advantages of the present invention more apparent and understandable, embodiments of the present invention will be described in detail below along with the accompanying drawings. Furthermore, the directional terms mentioned in the present invention include, for example, up, down, top, bottom, front, back, left, right, inside, outside, side, peripheral, central, horizontal, transverse, vertical, longitudinal, axial, Radial, uppermost or lowermost, etc., are only directions with reference to the attached drawings. Therefore, the directional terms used are to illustrate and understand the present invention, but not to limit the present invention.

Please refer to FIG. 1 , which is a mechanism for detecting internal thread defects according to an embodiment of the present invention. The mechanism includes a bracket unit 2, a rotating unit 3, a clamping unit 4 and a camera module 5. The detailed structure, assembly relationship and operating principle of each component will be described in detail below.

Please refer to FIGS. 1 and 2 . The bracket unit 2 includes a base 21 and an upright frame 22 . The upright frame 22 is disposed on the base 21 . In this embodiment, as shown in FIG. 2 , the upright frame 22 has a back plate 221 and a Z-axis sliding table 222 . The back plate 221 is provided on the base 21 , and the Z-axis sliding table 222 is locked on the base. On the back plate 221 , the Z-axis slide 222 is used to adjust the vertical height of the camera module 5 .

Referring to Figures 1 and 3, the rotating unit 3 is disposed on the base 21. The rotating unit 3 includes a rotating platform 31 and a driving member 32, and the rotating platform 31 has a tube body 311 and an extension platform. 312. A pulley 313 and a belt 314, wherein the tube body 311 penetrates the base 21 (see Figure 5), the extension platform 312 is arranged on the upper edge of the tube body 311, and the pulley 313 is arranged on the bottom of the tube body 311 , the belt 314 is sleeved on the pulley 313 and is configured to transmit the power of the driving member 32 . In this embodiment, as shown in FIG. 4 , the driving member 32 drives the extension platform 312 of the rotary table 31 to rotate along a rotation axis L1. For example, the extension platform 312 of FIG. 4 is rotated 90 degrees to become the extension platform 312 of FIG. 6 .

Please refer to Figures 3 and 5. The rotating unit 3 also includes a sensing piece 33, a sensor 34 and a sensor bracket 35. The sensing piece 33 is fixed below the pulley 313. The sensor 34 is disposed on the base 21. The sensor 34 is configured to sense the position of the sensing piece 33 to determine whether the state of the rotary table 31 is rotating or stopped. The sensor bracket 35 is locked on the side of the base 21. The edge is used to support and fix the sensor 34.

Referring to Figures 3, 4 and 6, the clamping unit 4 is disposed on the extended platform 312 of the rotary table 31. The clamping unit 4 includes two clamping arms 41, and the clamping arms 41 are configured to jointly clamp a The part to be tested 101 (such as a nut), wherein the clamping arms 41 are driven by the rotating table 31 so that the part to be tested 101 is clamped and rotates along a central axis L2, and the central axis L2 is coaxial with the rotation axis L1 . In addition, the clamping unit 4 further includes two clamping ends 42. The clamping ends 42 are concave and are respectively formed on the clamping arms 41, and the clamping ends 42 are configured to abut against the to-be-used clamping arms 41. Two opposite surfaces of the test piece 101. In this embodiment, the position of the clamping ends 42 is opposite to a through hole 310 of the tube body 311. The through hole 310 is configured for the piece to be tested 101 to pass, so that the piece to be tested 101 is collected in the The designated area below the pipe body 311, such as the detection qualified area and the detection defect area.

Continuing to refer to FIGS. 3 , 4 and 6 , the clamping unit 4 further includes a cylinder clamp 43 , the clamping arms 41 are arranged on the cylinder clamp 43 , and the cylinder clamp 43 is arranged on the rotary table 31 On the extension platform 312 , the cylinder clamp 43 is configured to control the opening and closing of the clamp arms 41 .

Please refer to Figures 1, 2 and 7. The camera module 5 is disposed on the Z-axis sliding table 222 of the upright frame 22, and the camera module 5 is separated from the clamping unit 4 by a distance. The camera module 5 is 5 includes a tilt-shift lens 51 (tilt-shift lens), a camera 52 and an annular light source 53. The tilt-shift lens 51 is arranged in the annular light source 53, and the tilt-shift lens 51 is located between the camera 52 and the clamp. Between units 4, in which the tilt-shift lens 51 is configured to use a lens that moves the main optical axis (tilt or translation) for shooting, an angle of a lens plane P1 of the tilt-shift lens 51 can be adjusted such that the lens plane P1 is A photographing plane P2 of the part to be tested 101 intersects with an imaging plane P3 of the camera 52 , which is Scheimpflug's principle, so as to focus on the internal thread of the part to be tested 101 and capture an image.

According to the above structure, the piece to be tested 101 can be placed between the clamping arms 41 through automated or manual methods, and the cylinder clamp 43 is used to control the opening and closing status of the clamping arms 41 to move the piece to be tested 101 is clamped between the clamping ends 42. Then, the photography module 5 is moved to a shooting position, and the tilt-shift lens 51 is adjusted at the same time to align the lens plane P1 with the shooting plane P2 of the device under test 101. And the imaging plane P3 of the camera 52 intersects, wherein the shift operation of the shift lens 51 is used to change the position of the focal plane, so that the clear range distribution of the imaging plane P3 is changed, so as to achieve depth of field control and zoom aperture imaging quality. Both of them can be taken into consideration, and a higher-definition photographed image of the internal thread of the object under test 101 can be obtained. In addition, the processor's artificial intelligence deep learning is used to perform defect detection and judgment, such as identifying defects in the internal thread of the nut (such as burrs, particles, and vibration knives, etc.). The inspected piece 101 will be removed from these clamping arms. 41 are loosened and passed through the through hole 310, and then are classified and collected in a designated area below the tube body 311, such as a qualified area or a defective area.

As mentioned above, the mechanism for detecting internal thread defects of the present invention is to change the position of the focal plane through the tilt-shift operation of the tilt-shift lens 51, so as to obtain a higher-definition photographed image of the internal thread of the object to be tested 101. , so that defects in internal thread detection are not limited to occurring in the tooth valley or tooth peak, and can effectively solve the problem that ordinary lenses cannot capture the complete internal thread image of the nut and detect smaller-sized defects. In addition, the rotation axis L1 of the extension platform 312 rotates coaxially with the central axis L2 of the object to be tested 101, so that the object to be tested 101 will not be deflected when being rotated by the extension platform 312. Furthermore, the hollow design of the tube body 311 allows the parts to be tested 101 after detection and judgment to be sorted and collected directly through the through hole 310 in the area below the tube body 311. Therefore, it can cooperate with the actual production line to carry out advanced feeding and post-processing. A coherent process of inspection and re-discharging reduces inspection time and increases production efficiency.

Please refer to FIG. 8 , which is a method for detecting internal thread defects according to an embodiment of the present invention. The method includes a preparation step S201, a feeding step S202, an imaging step S203, and a discharging step S204. The present invention will describe the relationship between each step and its operating principle in detail below.

Please refer to Figure 8 and as shown in Figure 1, in the preparation step S201, a bracket unit 2, a rotation unit 3, a clamping unit 4 and a photography module 5 are prepared, wherein the rotation unit 3 is disposed on the bracket On a base 21 of the unit 2, the clamping unit 4 is arranged on a rotating platform 31 of the rotating unit 3. The photography module 5 is arranged on a stand 22 of the bracket unit 2 and is connected with the clamping unit 4. Set some distance apart.

Please refer to Figure 8 and as shown in Figure 1, in the feeding step S202, a piece to be tested 101 is placed between the two clamping arms 41 of the clamping unit 4, so that the clamping arms 41 jointly clamp the piece. Part under test 101. In this embodiment, the object to be tested 101 can be placed between the clamping arms 41 through automated or manual methods, and the opening and closing states of the clamping arms 41 are controlled by the cylinder jaws 43 of the clamping unit 4 The piece to be tested 101 is clamped between the clamping ends 42 .

Referring to FIG. 1 , in the imaging step S203 , a tilt-shift lens 51 of the photography module 5 is used to adjust the tilt-shift lens 51 to focus on the internal thread of the object to be tested 101 and capture an image. Specifically, the photography module 5 is moved to a shooting position, and the tilt-shift lens 51 is adjusted at the same time, so that the lens plane P1 intersects the shooting plane P2 of the object under test 101 and the imaging plane P3 of the camera 52, where The shift operation of the shift lens 51 is used to change the position of the focal plane, so that the clear range distribution of the imaging plane P3 is changed, so as to achieve both depth of field control and imaging quality of the zoom aperture, and then the object under test 101 The internal thread can obtain higher-definition shooting images. In this embodiment, the photography module 5 captures the image of the object to be tested 101 and uses a driving member 32 of the rotating unit 3 to drive the rotating stage 31 to rotate along a rotating axis L1, in which the clamping arms 41 Driven by the rotating stage 31 , the object under test 101 is clamped and rotates along a central axis L2 , and the central axis L2 is coaxial with the rotation axis L1 .

Please refer to FIG. 1 . In the discharging step S204 , the object to be tested 101 is withdrawn from the clamping arms 41 , and a tube passing through the rotating stage 31 is imaged based on the imaging result of the object to be tested 101 . The parts to be tested 101 are classified through a through hole 310 of 311, so that the parts to be tested 101 are collected in designated areas below the tube body 311, such as the detection qualified area and the detection defective area.

As mentioned above, the method for detecting internal thread defects of the present invention is to change the position of the focal plane through the tilt-shift operation of the tilt-shift lens 51 to obtain a higher-definition photographed image of the internal thread of the object to be tested 101 , so that defects in internal thread detection are not limited to occurring in the tooth valley or tooth peak, and can effectively solve the problem that ordinary lenses cannot capture the complete internal thread image of the nut and detect smaller-sized defects. In addition, the rotation axis L1 of the extension platform 312 rotates coaxially with the central axis L2 of the object to be tested 101, so that the object to be tested 101 will not be deflected when being rotated by the extension platform 312. Furthermore, the hollow design of the tube body 311 allows the parts to be tested 101 after detection and judgment to be sorted and collected directly through the through hole 310 in the area below the tube body 311. Therefore, it can cooperate with the actual production line to carry out advanced feeding and post-processing. A coherent process of inspection and re-discharging reduces inspection time and increases production efficiency.

Although the present invention has been disclosed through embodiments, they are not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection of the present invention is The scope shall be determined by the appended patent application scope.

101: Part to be tested 2:Bracket unit 21:Base 22:Upright stand 221:Back plate 222:Z-axis slide table 3: Rotation unit 31: Rotary table 310:Through hole 311: Pipe body 312: Extended platform 313: Pulley 314:Belt 32:Driving parts 33: Sensing piece 34: Sensor 35: Sensor bracket 4: Clamping unit 41:Clamp arm 42: Clamping end 43: Cylinder clamp 5: Photography module 51: Tilt-shift lens 52:Camera 53: Ring light source L1:Rotation axis L2: central axis P1: Lens plane P2: Shooting plane P3: Imaging plane S201: Preparation steps S202: Feeding step S203: Image acquisition step S204: Discharging step

Figure 1 is a perspective view of a mechanism for detecting internal thread defects according to an embodiment of the present invention. FIG. 2 is an exploded view of a photography module of a mechanism for detecting internal thread defects according to an embodiment of the present invention. Figure 3 is an exploded view of a rotating unit and a gripping unit of a mechanism for detecting internal thread defects according to an embodiment of the present invention. Figure 4 is a partial perspective view of a mechanism for detecting internal thread defects according to an embodiment of the present invention. Figure 5 is a partial side view of a mechanism for detecting internal thread defects according to an embodiment of the present invention. Figure 6 is another partial perspective view of a mechanism for detecting internal thread defects according to an embodiment of the present invention. 7 is a schematic diagram of the lens plane, photographing plane and imaging plane of a mechanism for internal thread defect detection according to an embodiment of the present invention. Figure 8 is a flow chart of a method for internal thread defect detection according to an embodiment of the present invention.

2:Bracket unit

21:Base

22:Upright stand

3: Rotation unit

31: Rotary table

32:Driving parts

4: Clamping unit

5: Photography module

Claims (9)

A mechanism for detecting internal thread defects, the mechanism includes: a bracket unit, including a base and an upright frame, the upright frame is set on the base; a rotating unit, set on the base, wherein the rotating unit includes A rotary table and a driving member, the driving member drives the rotary table to rotate along a rotation axis; a clamping unit is provided on the rotary table, the clamping unit includes two clamping arms, and the clamping arms are configured together Clamping a piece to be tested, wherein the clamping arms are driven by the rotating stage so that the piece to be tested is clamped and rotated along a central axis, and the central axis is coaxial with the rotation axis; and a photography module is provided on On the upright stand and at a distance from the clamping unit, the photography module includes a tilt-shift lens and a camera, wherein the tilt-shift lens is configured to adjust an angle of a lens plane of the tilt-shift lens so that the The lens plane intersects a shooting plane of the object to be tested and an imaging plane of the camera to focus on the internal thread of the object to be tested and capture images; wherein the rotating stage has a tube body, an extension platform, a pulley and A belt, the tube body penetrates the base, the extension platform is arranged on the upper edge of the tube body, the pulley is arranged on the bottom of the tube body, the belt is sleeved on the pulley and is configured to transmit the power of the driving member. The mechanism for detecting internal thread defects as described in claim 1, wherein the clamping unit further includes two clamping ends, and the clamping ends are concave and respectively formed on the clamping arms. The holding end is configured to abut two opposite surfaces of the piece to be tested. The mechanism for detecting internal thread defects as described in claim 1, wherein the rotating unit further includes a sensing piece and a sensor, the sensing piece is fixed under the pulley, and the sensor is arranged on the base , and the sensor is configured to sense the position of the sensing piece to determine whether the state of the rotary table is rotating or stopped. An institution for internal thread defect detection as described in request item 1, wherein the The position of the clamping end is opposite to a through hole of the tube body, and the through hole is configured for the piece to be tested to pass through. The mechanism for detecting internal thread defects as described in claim 1, wherein the gripping unit further includes a cylinder jaw, the clamping arms are arranged on the cylinder jaw, and the cylinder jaw is arranged on the rotating table and configured to adjust the opening and closing of the clamp arms. The mechanism for detecting internal thread defects as described in claim 1, wherein the photography module further includes an annular light source, and the tilt-shift lens is arranged in the annular light source. A method for internal thread defect detection, the method includes: a preparation step of preparing a bracket unit, a rotating unit, a clamping unit and a photography module, the rotating unit is arranged on a base of the bracket unit, The clamping unit is arranged on a rotating platform of the rotating unit, and the photography module is arranged on a vertical frame of the bracket unit and is spaced a distance from the clamping unit, wherein the rotating platform has a tube body, an extension Platform, a pulley and a belt, the tube body runs through the base, the extension platform is set on the upper edge of the tube body, the pulley is set on the bottom of the tube body, the belt is sleeved on the pulley and is configured to drive a The power of the driving member; a feeding step, placing a piece to be tested between the two clamping arms of the clamping unit, so that the clamping arms jointly clamp the piece to be tested; and an imaging step, using the photography A tilt-shift lens of the module adjusts an angle of a lens plane of the tilt-shift lens so that the lens plane intersects a photographing plane of the object under test and an imaging plane of a camera of the photography module to focus the The internal thread of the part to be tested and captured. The method for internal thread defect detection as described in claim 7, wherein in the imaging step, the photography module captures the image of the object to be tested and simultaneously uses the driving member of the rotation unit to drive the edge of the rotation table The clamping arms are driven by the rotating stage so that the object to be tested is clamped and rotates along a central axis, and the central axis is coaxial with the rotating axis. The method for detecting defects in internal threads as described in claim 7, wherein the After the imaging step, the method for detecting internal thread defects further includes a discharging step, in which the piece to be tested is withdrawn from the clamping arms, and the piece to be tested passing through the rotary table is analyzed based on the imaging results of the piece to be tested. A through hole in the pipe body is used to classify the piece to be tested.

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