JPH071169A - Laser welding method and laser welding apparatus - Google Patents

Abstract

(57) [Abstract] [Purpose] When laser welding a small linear member to the outer peripheral surface of a cylindrical member, the structure for detecting the position of the welding line can be simplified, and the manufacturing cost can be reduced. [Structure] The laser welding method of the present invention uses a cylindrical member 12.
When the small piece 29 is welded to the outer peripheral surface of the, the reflection type optical sensor 20 provided so as to move integrally with the processing head 15 for irradiating the laser beam is used in the direction orthogonal to the welding line of both members 12, 29. And linearly scan both members 1
After detecting the surface shapes of Nos. 2 and 29, the position of the welding line is judged based on the detected surface shape data, and the machining head 15 is made to correspond to the judged position of the welding line and the laser beam is emitted from the machining head 15. Is to be irradiated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates a welding beam, which is a contact boundary line between two members, with a laser beam from a processing head in a state where a small linear member is in contact with the outer peripheral surface of a cylindrical member. TECHNICAL FIELD The present invention relates to a laser welding method and a laser welding apparatus for welding both members.

[0002]

2. Description of the Related Art As a welding device for welding a small piece such as a fin or a tab as a linear small member to the outer peripheral surface of a cylindrical member, there has been conventionally a configuration shown in FIGS. In this configuration, after the small piece 2 held by the holding jig 1 is brought into contact with the outer peripheral surface of the cylindrical member 3, the TIG torch 4 of the TIG welding apparatus is brought close to the contact boundary line between the member 3 and the small piece 2. Then, the tangential boundary line portion is welded. The gripping jig 1 includes a jig base 5, a work holder 7 rotatably provided on the jig base 5 via a pin 6, a spring 8 for urging the work holder 7 in the gripping direction, and a work piece. It is composed of a plate 9 for holding the presser 7 and a bolt 10 for fixing the plate 9 to the jig base 5.

However, in the above-described conventional welding apparatus, the influence of heat spreads over a fairly wide range around the welded portion when the welding is performed, and the welded portion is deformed by the pressing force of the gripping jig 1 and the thermal stress of the welded portion. There was a problem to do. In particular, in this case, when the influence range of heat is widened, the holding jig 1 for holding the small piece 2 is damaged or deformed by the heat, so that it is difficult to automatically supply the small piece 2. It was As a configuration for solving such a problem, there is a method of irradiating a laser beam on a welded portion to perform welding. According to this method, the range affected by heat is narrowed, and thermal deformation hardly occurs.

In the case of this laser welding, since the size of the spot diameter of the laser beam is as small as about 0.2 mm, it is necessary to accurately guide and irradiate the laser beam to the welding portion, that is, the welding line. For this purpose, it is necessary to accurately detect the position of the welding line, and as a device for detecting the position of the welding line in this way, there is a configuration described in Japanese Patent Application Laid-Open No. 60-96371. In this configuration, the periphery of the welding line is photographed by the television camera, and the image data photographed by the camera is processed by the image processing means to detect the position of the welding line.

[0005]

However, in the above-mentioned conventional configuration, the periphery of the welding line is photographed by the camera, and the position of the welding line is detected by processing the image data to process the data of the welding line. In addition, the data processing is quite complicated and troublesome, and there is a drawback that the manufacturing cost of the device becomes high.

Therefore, an object of the present invention is to simplify the structure for detecting the position of the welding line when laser welding a small linear member to the outer peripheral surface of a cylindrical member, and to reduce the manufacturing cost. A laser welding method and a laser welding apparatus capable of performing the above are provided.

[0007]

According to the laser welding method of the present invention, a linear small member is brought into contact with an outer peripheral surface of a cylindrical member to form a welding line which is a contact boundary line between both members. In the method of welding both members by irradiating a laser beam from the head, a linear reflection type optical sensor provided so as to move integrally with the processing head causes a straight line along a direction orthogonal to a welding line of the both members. After scanning the surface shape of both members, the position of the welding line is determined based on the detected surface shape data, and the laser beam is emitted from the processing head to the position of the determined welding line. It is characterized by being guided and irradiated.

Further, the laser welding apparatus of the present invention, in a state where a small linear member is brought into contact with the outer peripheral surface of a cylindrical member, the welding beam from the processing head to the welding line which is the contact boundary line between both members. In a device for irradiating both members by irradiating with the above, a reflection type optical sensor is provided which is provided so as to move integrally with the processing head, irradiates the surfaces of the both members with light, and detects the light reflected by the surfaces. , The position of the welding line is detected based on the detected surface shape data by linearly scanning along the direction orthogonal to the welding line of the both members by this reflection type optical sensor and detecting the surface shape of the both members. The present invention is characterized in that it is provided with a position determining means for making a determination, and a control means for controlling the position of the welding line determined by the position determining means to irradiate a laser beam from the processing head. .

[0009]

When a small linear member is brought into contact with the outer peripheral surface of the cylindrical member for welding, the position of the welding line is the most concave portion of the surface shape of both members. Therefore, if the surface shape of both members is detected by linearly scanning along the direction orthogonal to the welding line of both members, and the most concave portion is set as the position of the welding line based on the detected surface shape data. It is possible to accurately determine the position of the welding line. The present invention has been made paying attention to this point.

Therefore, according to the above means, the reflection type optical sensor provided so as to move integrally with the machining head linearly scans along the direction orthogonal to the welding line of both members, and both members are scanned. Since it is configured to detect the surface shape of
The position of the welding line can be accurately determined based on the detected surface shape data. In this case, since the reflection type optical sensor is simply provided in the processing head integrally and the data processing is very simple, the manufacturing cost is greatly increased as compared with the case of using the TV camera. Can be cheap.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First, in FIG. 3 showing the overall configuration of the laser welding apparatus, a front work chuck 13 and a rear work chuck 14 for chucking both ends of a long cylindrical member 12 are provided on a base 11. ing. By chucking the cylindrical member 12 between the front work chuck 13 and the rear work chuck 14, the cylindrical member 12 is fixed so as to extend along the X-axis direction (the horizontal direction in FIG. 3). It is configured to.

Further, on the base 11, a processing head 15 for irradiating a laser beam is passed through a head drive mechanism 16 and X-shaped.
Axial direction, Y-axis direction (left-right direction in FIG. 4), Z-axis direction (FIG. 3)
And in the vertical direction in FIG. 4). As shown in FIG. 1, the processing head 15 is provided with a laser output section 18 at the lower end of a cylindrical head body 17, and a condenser lens 19 is provided at the laser output section 18. . In this case, the laser light supplied from the laser oscillator passes through the inside of the head body 17 and the condenser lens 1
The laser beam is condensed by passing through 9 and becomes a laser beam, and the laser beam is output from the laser output unit 18 to a position directly below. A reflection type optical sensor 20 for detecting the position of the welding line is provided on the left side surface of the laser output section 18 in FIG.

As shown in FIG. 2, the reflection type optical sensor 20 is composed of a light emitting element 21, a light emitting side lens 22, a light receiving side lens 23 and a light receiving element 24. In this case, the detection light emitted from the light emitting element 21 is applied to the object to be detected via the light emitting side lens 22, and the reflected light reflected by the object to be detected is received by the light receiving element 24 via the light receiving side lens 23. It has become so. The reflective optical sensor 20 is configured to be controlled by the controller 25,
The controller 25 controls the light emitting element 21 to emit light and receives a light receiving signal from the light receiving element 24.

As shown in FIGS. 1 and 2, the machining head 15, that is, the head body 17, is moved and driven in the Y-axis direction (left-right direction in FIG. 1) by a Y-axis motor 26 via a feed screw 26a. It is configured to. The Y-axis servo motor 26 is configured to be drive-controlled by the control device 27. Furthermore, the processing head 15
Is controlled by the Z-axis servomotor 28 as shown in FIG.
It is configured to be moved and driven in the axial direction.

On the other hand, as shown in FIGS. 3 and 4, on the base 11, small pieces 29 (see FIGS. 1, 2 and 10) such as fins and tabs are automatically formed as linear small members. A small piece supply device 30 for supplying is provided so as to be movable in the X-axis direction via a rail or the like. The small piece supply device 30 will be described in detail below with reference to FIGS. 5 to 9.

First, FIG. 5 showing the front of the small piece supply device 30.
, The slide table 32 is placed on the substrate 31 in the X direction.
It is provided so as to be movable in the axial direction. A pallet 33 is placed and fixed on the slide table 32.
As shown in FIG. 5, the small pieces 29 are housed in a large number of grooves 33a formed on the upper surface of the pallet 33. Here, the drive mechanism of the slide table 32 will be described with reference to FIG. The slide table 32 is supported by two guide rails 34 so as to be movable in the X-axis direction (vertical direction in FIG. 6). Positioning portions 35 having a large number of ratchet-shaped teeth are provided on both left and right sides of the slide table 32 in FIG.

Outside the positioning parts 35, a claw member 36 having two claws 36a that engage with the teeth of each positioning part 35 is rotatable around a shaft 37 as a rotation fulcrum. It is provided. A spring 39 provided between each claw member 36 and the base metal 38 urges each claw member 36 to rotate in the engaging direction. Then, each claw member 36
Is configured to be rotated in the disengagement direction by the rod 40a of the cylinder 40. In this case, each claw member 36
By engaging and disengaging the tooth portions of the positioning portions 35 with each other, the positioning portion 35, that is, the slide table 32 is moved by a fixed amount. A sensor 41 for detecting the engagement and disengagement state of each claw member 36 is provided on the lower end side of each claw member 36 in FIG. Further, on the upper end side and the lower end side in FIG. 6 of the guide rail 34,
Sensors 42 and 43 for detecting the forward and backward limit positions of the slide table 32 are provided.

On the other hand, above the slide table 32,
As shown in FIG. 5, the gripping device 44 is arranged via the support leg portion 45. As shown in FIG. 7, the gripping device 44 is movably supported in a direction along the guide member 46 (up and down direction in FIG. 7) by being inserted into the guide member 46. It is configured to be driven to move in the above direction by the cylinder 47 shown. Further, as shown in FIG. 5, the gripping device 44 includes a support member 48, to which a guide member 46 is fitted and fixed, on a shaft 49 on the support leg 45.
It is configured to be rotatable around the shaft 49 as a rotation fulcrum by being pivotally supported via. In this case, the gripping device 44 is configured to be rotationally driven between the position shown in FIG. 7 and the position shown in FIG. 8 by the cylinder 50 also shown in FIG. 7. In addition, 51 and 51 are dampers, and these are for buffering the impact force when the gripping device 44 is rotated.

Now, a specific structure of the gripping device 44 will be described with reference to FIG. In FIG. 9, an air cylinder 52 is provided inside the gripping device 44,
The rod 53 of the air cylinder 52 is provided so as to be movable in the vertical direction in FIG. In this case, the rod 53
It is urged to move upward by a spring 54, and when the electromagnetic valve 55 is opened to supply air into the air cylinder 52, it moves downward. The rod 5
Sloping surface portions 53a are formed on both side surface portions of the lower end portion of No. 3.

At the lower end of the gripping device 44, a pair of fingers 55, 55 are provided so as to be rotatable around the shafts 56, 56 as pivotal fulcrums. The pair of fingers 55, 55 are capable of gripping the small piece 29 by gripping parts 55a, 55a at their lower end portions. These fingers 55, 5
5 is gripped by the springs 57, 57.
The upper end portion of each rod 53 abuts on the inclined surface portion 53 a of the rod 53 while being urged to rotate in a direction to release the gripping a. In this case, when air is supplied into the air cylinder 52 and the rod 53 is moved downward, the upper ends of the fingers 55, 55 are moved to the rod 53.
The grip portion 55a, 55a is opened by rotating in the grip release direction by being in contact with the slope portion 53a at the lower end of the grip portion 55a. Then, when the supply of air is stopped, the rod 53 moves upward, so that the fingers 55, 55 rotate in the gripping direction because their upper ends are in contact with the sloped portions 53a of the lower end of the rod 53. And its grip 55
The small piece 29 can be held by a and 55a.

Next, the operation of the above structure will be described with reference to FIG. First, both ends of the cylindrical member 12 are chucked to the front work chuck 13 and the rear work chuck 14, and fixed between the chucks 13 and 14. In addition, a large number of small pieces 2 are placed on the slide table 32 of the small piece supply device 30.
The pallet 33 containing 9 is placed and fixed. In this state, the cylinder 40 is appropriately driven to drive the slide table 3
2 is moved to a predetermined position and positioned so that the first small piece 29 accommodated in the pallet 33 is arranged immediately below the gripping device 44. Then, the solenoid valve 55 of the gripping device 44.
Is opened to supply air into the air cylinder 52 to move the rod 53 downward to open the grip portions 55a, 55a of the fingers 55, 55. Then, the cylinder 47 is driven to move the gripping device 44 downward in FIG. 7, and the gripping portions 55a, 55a of the fingers 55, 55 are moved down to a position where the small piece 29 can be gripped.

In this state, when the electromagnetic valve 55 is closed and the air supply is stopped, the grips 55 of the fingers 55, 55 are held.
a and 55a grip the small piece 29. After this, cylinder 4
7 is driven to move the gripping device 44 upward in FIG. 7, and the cylinder 50 is driven to rotate the gripping device 44 to the position shown in FIG. Then, the cylinder 47 is driven to move the gripping device 44 obliquely downward in FIG. 8, and as shown in FIG. 8, a small piece 29 is attached to the outer peripheral surface of the cylindrical member 12.
Abut.

Now, in this abutting state, a process for accurately detecting the position of the welding line which is the abutting boundary line between the outer peripheral surface of the cylindrical member 12 and the small piece 29 is carried out. Specifically, the processing head 1
By the reflection type optical sensor 20 integrally provided in 5, the members 12 and 29 are scanned linearly along a direction orthogonal to the welding line of the members 12 and 29, in this case, the Y-axis direction. Detect the surface shape. By this scanning, the reflection type optical sensor 2
The voltage level of the light receiving signal output from the light receiving element 24 of 0 changes as shown in the graph of FIG. In this graph, the origin (left end position) in the Y-axis direction is the cylindrical member 1
2 is the uppermost portion A of the outer peripheral surface, and the point P (right end position) where the voltage level sharply drops is the rightmost portion B of the outer peripheral surface of the cylindrical member 12.

Here, when the linear small piece 29 is brought into contact with the outer peripheral surface of the cylindrical member 12 for welding, the position of the welding line is the most concave portion of the surface shape of both members 12, 28. Therefore, in the graph of FIG. 11, the point Q at which the voltage level of the received light signal is the lowest coincides with the position C of the welding line. Therefore, the point Q where the voltage level of the received light signal is the lowest
The position C of the welding line can be accurately detected by detecting the position of. In the case of this embodiment, as shown in FIG. 1, the position of the reflection type optical sensor 20 and the position of the processing head 15 are deviated by the distance L. Therefore, the control device 27 shown in FIG. The position C of the welding line is accurately determined by performing a calculation for correcting the position of the point Q having the lowest level by the distance L. Then, the control device 27 drives the Y-axis servo motor 26 to move the machining head 15 to the position C determined above and position it.

As a result, the laser beam output from the processing head 15 can be accurately applied to the welding line.
In this case, since the welding line is along the X-axis direction, if the processing head 15 is moved in the X-axis direction while irradiating the laser beam, the laser beam is irradiated so as to trace the welding line. Therefore, the small piece 29 can be laser-welded to the outer peripheral surface of the cylindrical member 12. Hereinafter, as shown in FIG. 10, a large number of small pieces 29 are formed on the outer peripheral surface of the cylindrical member 12 by repeating the process of welding the required number of small pieces 29 to the predetermined position on the outer peripheral surface of the cylindrical member 12. 29
Can be welded. In this case, each small piece 29 is automatically supplied by the small piece supply device 30. When detecting the position C of the welding line, both ends of the welding line are scanned by the reflective optical sensor 20 (in short, 2
It is preferable that the small piece 29 is vertically erected on the outer peripheral surface of the cylindrical member 12 by performing such scanning.

In the case of the above embodiment, the reflection type optical sensor 20 is simply provided on the processing head 15 and the voltage levels of the light receiving signals obtained by the reflection type optical sensor 20 are compared. Since it is only necessary to perform data processing that is done, data processing is also very easy,
The manufacturing cost can be significantly reduced as compared with the conventional configuration in which a television camera is provided and image data obtained by the television camera is processed.

[0027]

As is apparent from the above description, the present invention provides a welding line which is a contact boundary line between a cylindrical member and a small member by a reflection type optical sensor provided so as to move integrally with a machining head. After linearly scanning along the direction orthogonal to, the surface shapes of both members are detected, the position of the welding line is determined based on the detected surface shape data, and the position of the determined welding line is determined. Since the laser beam is guided and irradiated from the processing head, the structure for detecting the position of the welding line can be simplified and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view around a processing head showing an embodiment of the present invention.

[Fig. 2] Side view of the area around the reflective optical sensor

FIG. 3 is a side view of the entire laser welding device.

FIG. 4 is a front view of the entire laser welding apparatus.

FIG. 5 is a front view of the small piece supply device.

FIG. 6 is a front view around the slide table.

FIG. 7 is a vertical sectional side view of the small piece supply device.

FIG. 8 is a view corresponding to FIG. 7, showing a state in which the grip device is rotated.

FIG. 9 is a vertical sectional view of a gripping device.

FIG. 10 is a perspective view of a large number of small pieces welded to a cylindrical member.

FIG. 11 is a graph showing changes in the voltage level of the received light signal when the welding line is scanned by the reflection type optical sensor.

FIG. 12 is a side view of the vicinity of the component holding device showing the conventional configuration.

FIG. 13 is a vertical sectional front view of the periphery of the component holding device.

[Explanation of symbols]

11 is a base, 12 is a cylindrical member, 15 is a processing head, 1
7 is a head main body, 18 is a laser output section, 19 is a condenser lens, 20 is a reflection type optical sensor, 25 is a controller, 26
Is a Y-axis servomotor, 27 is a control device (position determination means,
Control means), 28 is a Z-axis servomotor, 29 is a small piece (small part), 30 is a small piece supply device, 32 is a slide table, 33 is a pallet, 44 is a gripping device, and 55 is a finger.

Claims (2)

[Claims] 1. A welding method for welding both members by irradiating a welding line, which is a contact boundary line between the two members, with a laser beam from a processing head in a state where a small linear member is in contact with the outer peripheral surface of the cylindrical member. In the method, by a reflection type optical sensor provided so as to move integrally with the processing head, linearly scans along the direction orthogonal to the welding line of the both members to determine the surface shape of the both members. After the detection, the position of the welding line is determined based on the detected surface shape data, and a laser beam is guided from the machining head to the position of the determined welding line to irradiate the laser beam. Laser welding method. 2. A welding method for irradiating a welding line, which is a contact boundary line between both members, with a laser beam from a processing head in a state where a linear small member is in contact with the outer peripheral surface of the cylindrical member. In the device described above, a reflection type optical sensor, which is provided so as to move integrally with the processing head, irradiates the surfaces of the both members with light and detects the light reflected by the surfaces, and the reflection type optical sensor Position determination means for linearly scanning along the direction orthogonal to the welding line of both members to detect the surface shapes of the both members, and for determining the position of the welding line based on the detected surface shape data, A laser welding apparatus, comprising: a control unit that controls the processing head to irradiate a laser beam to the position of the welding line determined by the position determination unit.