JP2006007303A - Visual sensor for welding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably perform image pick-up over a long period by preventing the damage of an optical system caused by spatters and fumes during welding by a simple constitution, and to reduce the production cost. <P>SOLUTION: A shutter 16 composed of a pair of shutter blades 15a, 15b is arranged in front of a transparent protective board 10 provided at a photographing window in a photographing means 2, and the pair of shutter blades 15a, 15b are rocked right and left via link mechanisms 14a, 14b by the stroke of a plunger 17 when a solenoid 13 is driven, so that the shutter 16 is opened and shut. In this way, there is no need of narrowing light made incident on the photographing means 2 by a pinhole, and there is no need of using a special lens as a lens 6 in an optical system of the photographing means 2, thus the production cost of the photographing means 2 is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In this invention, when performing arc welding, the welding position and the position of the welding wire, the size of the weld pool, and the like are obtained. This relates to the prevention of optical system damage due to spatter and fumes during welding.

  When performing arc welding, in order to adaptively control the welding conditions so that the welding line copy of the welding torch and the size of the molten pool are properly maintained, a visual sensor having a CCD camera or the like is used to detect the welding part and its vicinity. An image is taken. In order to process the image picked up by this visual sensor and control the welding line tracing and the size of the weld pool with high accuracy, it is necessary to arrange the visual sensor in the vicinity of the welding torch, that is, the arc. Thus, when a visual sensor is arrange | positioned in the vicinity of a welding torch, the countermeasure with respect to the disturbance by welding, for example, a sputter | spatter and a fume, is required.

As a countermeasure, for example, as shown in Patent Document 1, a pinhole having a diameter of 2 mm or less is provided in front of the protective glass provided at the incident portion of the visual sensor, and air or gas is ejected from the inside of the pinhole to cause spatter and fume. It prevents intrusion and prevents damage to the lens and the interference filter of the incident part, and as shown in Patent Document 2, a protective plate disposed on the front surface of the lens of the incident part of the visual sensor is used for photographing. A pinhole, which is a hole, and a large number of gas jets are provided around the pinhole, and a shield gas is jetted from the gas jet to prevent spatter and fumes from entering. In addition, as shown in Patent Document 3, a circular copper plate having a small hole for photographing, a slit for position detection, and a glass surface cleaning brush is disposed in front of the protective glass provided on the front surface of the pinhole lens, and the circular copper plate is connected to a direct current. It is rotated by a motor, and the image is captured only when the small hole for shooting and the pinhole overlap, and the dirt on the protective glass surface due to fumes is removed with a glass surface cleaning brush.
JP-A-7-299565 JP-A-9-38774 JP-A-10-308888

  In Patent Documents 1 to 3, in order to protect the photographing window glass and lens of the visual sensor, the area of the photographing window is reduced using a pinhole, and welding spatter, fumes, etc. come into contact with the photographing window glass and lens. Is reduced. Thus, in order to reduce the area of the photographing window and obtain a good image, a normal lens cannot be used, and a special lens needs to be used, and the visual sensor becomes expensive.

  Moreover, although the visual sensor shown in patent document 1 and patent document 2 can prevent a fume from entering from the pinhole provided in front of protective glass or a lens with the gas to eject, it prevents that a sputter | spatter enters from a pinhole. For this purpose, it is necessary to increase the pressure and flow rate of the gas to be ejected. If the pressure and flow rate of the gas to be ejected are made very large in this way, it becomes a disturbance to the inert gas that protects the arc and the molten pool, and the protective effect of the inert gas is impaired.

  In addition, when a circular copper plate that rotates in front of the protective glass is provided as in the visual sensor shown in Patent Document 3, it is necessary to provide a DC motor or a rotation transmission mechanism that rotates the circular copper plate at the tip of the visual sensor. There is a disadvantage that the sensor becomes larger.

  The present invention improves such disadvantages, prevents damage to the optical system due to spatters and fumes during welding with a simple configuration, and enables stable imaging for a long period of time, and is a compact and inexpensive manufacturing visual sensor. Is intended to provide.

  The welding visual sensor of the present invention has a photographing means and a shutter mechanism, and the photographing means has a transparent protective plate provided on a photographing window having an opening necessary for photographing on the front surface of the CCD camera, the optical system and the housing. The shutter mechanism section includes a direct-acting solenoid, a pair of link mechanisms, and a shutter including a pair of shutter blades, and one pair of link mechanisms is rotatable at one end to a solenoid plunger. The linked link and the intermediate portion are rotatably held by the shutter mechanism housing, one end portion is rotatably connected to the other end portion of the link, and the shutter blade is fixed to the other end portion. And a pair of shutter blades arranged so that the ends overlap each other on the front surface of the transparent protective plate provided in the photographing window of the photographing means, and the plunger Wherein the opening and closing swings to the right and left via the link mechanism by the stroke.

  The pair of shutter blades is preferably formed of a hard resin having heat resistance.

  In addition, a cooling gas supply port is provided on the surface opposite to the photographing window of the housing containing the photographing means, and the outer periphery of the transparent protective plate provided in the photographing window is cooled along the surface of the transparent protective plate. A plurality of cooling gas discharge ports for discharging gas are provided.

  Further, the front surface of the shutter and the transparent protective plate provided in the photographing window of the housing containing the photographing means has a protective cap having a photographing opening, and the side surface of the protective cap is provided with the cooling gas discharge port. It is desirable to have a slit for discharging the discharged cooling gas and sputter particles or powder that have entered the protective cap to the outside.

  According to the present invention, a shutter composed of a pair of shutter blades is arranged on the front surface of a transparent protective plate provided in a photographing window of a photographing means, and a pair of shutters via a link mechanism by a stroke of a plunger when a solenoid is driven. Since the shutter blade is swung left and right to open and close the shutter, there is no need to use a pinhole to squeeze the light incident on the photographing means, and there is no need to use a special lens for the optical system lens of the photographing means. Production costs can be reduced.

  Also, since the pair of shutter blades are made of heat-resistant hard resin, the shutter blades are lightened to reduce the moment of inertia, and the delay time from when the solenoid starts to drive until the shutters are fully opened and closed Because it is as short as possible, the spatter flying on the transparent protective plate provided in the photographing window of the photographing means can be greatly reduced, preventing the transparent protective plate from becoming dirty with spatter and fume and improving the durability of the photographing means. it can.

  Furthermore, by using a hard resin as the shutter blade, it is possible to make it difficult for spatter to adhere to the surface of the shutter blade.

  In addition, the cooling gas that has cooled the inside of the photographing means is discharged along the transparent protective plate from a plurality of cooling gas discharge ports provided on the outer peripheral portion of the transparent protective plate provided in the photographing window. The adhering spatter can be removed and cleaned, and the durability of the visual sensor can be improved by preventing the transparent protective plate from becoming dirty.

  Furthermore, since the spatter removed from the surface of the transparent protective plate is discharged to the outside together with the cooling gas from the transparent protective plate provided in the photographing window and the slit provided in the side surface of the protective cap provided in front of the shutter, the protective cap Spatter can be prevented from staying inside.

  FIG. 1 is a block diagram of a visual sensor according to the present invention. As shown in the figure, the visual sensor 1 includes a photographing unit 2 and a shutter mechanism unit 3. The photographing means 2 includes a CCD camera 5 housed in a housing 4, an optical system 9 having a lens 6, a light wavelength band filter 7 and a neutral density filter 8, and a photographing window having an opening necessary for photographing on the front surface of the housing 4. The transparent protective plate 10 is provided. A cooling gas supply port 11 is provided on the surface of the housing 4 opposite to the photographing window, and a plurality of cooling gas exhausts for discharging the cooling gas along the surface of the transparent protective plate 10 are provided on the outer periphery of the transparent protective plate 10. It has an outlet 12.

  As shown in the side view of FIG. 2, the shutter mechanism unit 3 includes a shutter 16 having a direct acting solenoid 13, a pair of link mechanisms 14 a and 14 b, and a pair of shutter blades 15 a and 15 b. The solenoid 13 is fixed to the housing 18 of the shutter mechanism unit 3 so that the plunger 17 linearly moves along the photographing direction of the photographing unit 2, and the distal end portion of the plunger 17 is attached to the photographing direction of the photographing unit 2 by a tension spring 19. It is energized. The pair of link mechanisms 15a and 15b is rotatably held at one end thereof by a link 20 that is rotatably connected to the tip of the plunger 17 of the solenoid 13 and at an intermediate portion thereof by the housing 18 of the shutter mechanism portion 3. And an oscillating arm 21 having a shutter blade 15 fixed to the other end. The shutter blades 15a and 15b are formed of a hard resin such as heat-resistant allyl resin, polyimide resin or FRP. The housing 18 of the shutter mechanism unit 3 is fixed to the side surface of the housing 4 of the photographing unit 2, and the shutter blades 15 a and 15 b overlap with each other on the front surface of the transparent protective plate 10 provided in the photographing window of the photographing unit 2. Further, it is fixed to each swing arm 21 of the pair of link mechanisms 14a, 14b. The housing 18 of the shutter mechanism unit 3 has a closed position restricting member 22 and an open position restricting member 23 for positioning the swing end of each swing arm 21 in order to restrict the closed position and the open position of the shutter 16. The front surface of the shutter 16 is formed of a material having high heat resistance and heat insulation, such as an epoxy resin containing glass fiber, and is covered with a protective cap 25 having an opening 24 for photographing on the front surface. On the side surface of the protective cap 25, there is a slit 26 for discharging the cooling gas discharged from the cooling gas discharge port 12 of the photographing means 2 and sputter particles or powder entering the protective cap to the outside.

  When this visual sensor 1 is used to adaptively control the welding conditions so as to capture an image of the vicinity of the welded part during arc welding and appropriately maintain the welding line tracing of the welding torch and the size of the molten pool, etc. As shown in FIG. 3, the visual sensor 1 is arranged at a certain angle in the vicinity of the welding torch 31 for welding the base material 30 and images of the welded portion and the vicinity thereof are taken. The image photographed by the visual sensor 1 is subjected to image processing by the image processing device 32, and the feature amount of the groove shape and the molten pool state is obtained. The welding control device 33 controls the copying of the welding torch 31, the weaving width, the moving speed, and the feed amount of the wire 34 according to the groove shape and the state of the molten pool.

  When the photographing unit 2 of the visual sensor 1 does not photograph the welded portion and the vicinity thereof, the plunger 17 is not sucked without flowing current through the coil of the solenoid 13 included in the shutter mechanism unit 3. At this time, since the plunger 17 is pulled in the photographing direction of the photographing means 2 by the tension spring 19 and moved to the front side, the distal end portion of the swing arm 21 to which the shutter blades 15a and 15b are fixed is centered via the link 20, respectively. The shutter blades 15a and 15b are overlapped and positioned by the closed position restricting member 22 so that the shutter 16 is closed. When taking an image of the welded portion and the vicinity thereof with the photographing means 2, when the plunger 17 is sucked by passing a current through the coil of the solenoid 13, the plunger 17 swings via the link 20 of the link mechanisms 14 a and 14 b. The arm 21 is swung left and right, and the swing arm 21 is positioned by the open position restricting member 23 to open the shutter 16. When the current flowing through the coil of the solenoid 13 is interrupted while the shutter 16 is open, the plunger 17 moves to the front side, and the swing arm 21 moves to the center side via the link 20 by the stroke of the plunger 17. Then, the shutter 16 is closed. By driving the solenoid 13 in this way, the shutter 16 can be opened and closed, and it is not necessary to stop the light incident on the photographing means 2 with a pinhole. Therefore, a special lens is used for the lens 6 of the photographing means 2. This is unnecessary, and the production cost of the photographing means 2 can be reduced.

  When the solenoid 13 is driven to open and close the shutter 16, the shutter 16 is completely energized after the coil of the solenoid 13 is energized due to the characteristics of the solenoid 13 and the inertia of the link mechanisms 14a and 14b and the shutter blades 15a and 15b. Until the shutter 16 is completely closed after the energization of the solenoid 13 and the coil is cut off. When taking an image of the welded part and its vicinity, it is necessary to make this delay time as short as possible in order to reduce the influence of spatter and fumes on the transparent protective plate 10 of the photographing means 2. The influence of the characteristics of the solenoid 13 can be reduced by selecting the solenoid 13 having an appropriate characteristic. Further, the inertia of the link mechanisms 14a and 14b and the shutter blades 15a and 15b can be reduced by reducing the weight of the shutter blades 15a and 15b having a large moment of inertia. Therefore, the shutter blades 15a and 15b are made of a heat-resistant allyl resin, polyimide resin, FRP or other hard resin to reduce the weight, to reduce the moment of inertia and to shorten the delay time as much as possible. Further, by using a hard resin such as FRP as the shutter blades 15a and 15b, it is possible to make it difficult for spatter to adhere to the surfaces of the shutter blades 15a and 15b.

  Since the photographing by the CCD camera 5 of the photographing means 2 is not started within the delay time generated when the shutter 16 is opened and closed, the image processing device 32 is connected to the central processing device 35 and the digital signal as shown in the block diagram of FIG. In addition to the input / output unit (DIO input / output unit) 36, the shutter control unit 37, and the image input control unit 38, a delay circuit 39 is provided. The central processing unit 35 processes the captured image and controls the operation of the entire apparatus. When an interrupt signal for starting imaging is input from the welding control unit 33, the central processing unit 35 outputs an imaging permission signal to the input / output unit 36. The input / output unit 36 sends a photographing permission signal output from the central processing unit 35 to the shutter control unit 37 and the delay circuit 39. As shown in the time chart of FIG. 5, the shutter control unit 37 opens the shutter 16 by supplying a current to the coil of the solenoid 13 when a photographing permission signal is sent. When the photographing permission signal is sent, the delay circuit 39 sends a photographing trigger signal delayed by a delay time set in the central processing unit 35 to the image input control unit 38. The image input control unit 38 starts photographing by the CCD camera 5 based on the sent photographing trigger signal, and sends the photographed image signal to the central processing unit 35. When the photographing of the CCD camera 5 by the photographing trigger signal is completed, the shutter control unit 37 cuts off the current flowing through the coil of the solenoid 13 and closes the shutter 16.

  As described above, since the shutter 16 is opened only when the imaging unit 2 captures the vicinity of the welded portion, it is possible to greatly reduce the spatter flying on the transparent protective plate 10 of the imaging unit 2. It is possible to prevent contamination by spatter and fume and to improve the durability of the photographing means 2.

  Further, when the visual sensor 1 is arranged close to the welding torch 31, the temperature inside the photographing means 2 rises. In order to suppress this temperature rise, the cooling gas is introduced from the cooling gas supply port 11 of the housing 4 and circulated in the housing 4, and the cooling gas is supplied to a plurality of cooling gas discharge ports provided on the outer peripheral portion of the transparent protective plate 10. 12 is discharged along the transparent protective plate 10. The discharged cooling gas is discharged along the transparent protective plate 10 to remove and clean the spatter and powder adhering to the surface of the transparent protective plate 10. The durability of the sensor 1 can be increased. Further, since the removed spatter, powder and the like are discharged to the outside together with the cooling gas from the slit 26 provided on the side surface of the protective cap 25, it is possible to prevent the spatter, powder and the like from staying in the protective cap 25.

  In addition, during vertical welding or horizontal welding, spatter or the like that has entered the protective cap 25 can be dropped from the slit 26 by gravity or vibration, and the spatter or the like that has entered the protective cap 25 can be efficiently discharged to the outside. can do.

It is a block diagram of the visual sensor of this invention. It is a side view which shows the structure of a shutter mechanism part. It is an arrangement plan of a visual sensor when photographing a welded part and its vicinity with a visual sensor. It is a block diagram which shows the structure of an image processing apparatus. It is a time chart which shows operation | movement when image | photographing a welding part and its vicinity with a visual sensor.

Explanation of symbols

1; visual sensor, 2; photographing means, 3; shutter mechanism, 4; housing for photographing means,
5; CCD camera, 6; Lens, 7; Optical wavelength band filter, 8;
9; optical system, 10; transparent protective plate, 11; cooling gas supply port, 12; cooling gas discharge port,
13; Solenoid; 14; Link mechanism; 15; Shutter blade;
16; shutter; 17; plunger; 18; housing of shutter mechanism;
19; tension spring; 20; link; 21; swing arm; 22; closed position restricting member;
23: Open position restricting member, 24: Opening for photographing, 25;
26; slit, 30; base material, 31; welding torch, 32; image processing apparatus,
33; welding control device, 34; wire, 35; central processing unit, 36; DIO input / output unit,
38; Image input control unit 36; Delay circuit.

Claims (4)

Having photographing means and shutter mechanism,
The photographing means has a transparent protective plate provided in a photographing window having an opening necessary for photographing at the front surface of the CCD camera, the optical system and the housing,
The shutter mechanism unit has a shutter composed of a direct acting solenoid, a pair of link mechanisms and a pair of shutter blades, and one pair of link mechanisms is rotatably connected to a solenoid plunger. A swing arm in which a link and an intermediate part are rotatably held by a housing of a shutter mechanism part, one end part is rotatably connected to the other end part of the link, and a shutter blade is fixed to the other end part The pair of shutter blades are arranged so that the ends overlap each other on the front surface of the transparent protective plate provided in the photographing window of the photographing means, and swing left and right through the link mechanism by the plunger stroke A visual sensor for welding characterized by opening and closing.   The welding visual sensor according to claim 1, wherein the pair of shutter blades is formed of a hard resin having heat resistance.   A cooling gas supply port is provided on the surface opposite to the photographing window of the housing containing the photographing means, and a cooling gas is provided along the surface of the transparent protective plate on the outer peripheral portion of the transparent protective plate provided on the photographing window. The welding visual sensor according to claim 1, further comprising a plurality of cooling gas discharge ports for discharging the gas. A transparent protective plate provided in the photographing window of the housing housing the photographing means and a front face of the shutter have a protective cap having an opening for photographing, and a side surface of the protective cap is provided with the cooling gas discharge port. The visual sensor for welding according to claim 1, 2 or 3, further comprising a slit for discharging the discharged cooling gas and sputtered particles or powder entering the protective cap to the outside.

Images