JPH0699298A - Laser beam welding equipment - Google Patents

Abstract

PURPOSE:To set the pressurizing force of both members to be joined by laser beam welding or a gap provided between both members to a value in accordance with the size and material of the members. CONSTITUTION:A movable table 23 is moved in the arrow A direction by a motor 27. When a member held on a moving side holding mechanism 29 abuts on a member held on a fixed side holding mechanism 30, since a load current of the motor 27 increases, this point of time is made to the point of time when both members abut on each other. After this, when the motor 27 is rotated in the normal direction or in the reverse direction till the number of revolutions detected by an encoder 67 (moving quantity detection means) attains a set value, the movable table 23 is further moved in the arrow A direction or in the arrow B direction, both members are pressed with the set pressurizing force or the gap having set dimensions is generated between both members. In this state, the ends of both members are irradiated with a laser beam to perform welding while rotating both members by a main spindle driving motor 48.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser welding apparatus for irradiating and welding a laser beam to the ends of two members to be joined.

[0002]

2. Description of the Related Art As a method for joining members, there are pressure welding and gas welding. However, in such a method, the welded portion is deformed under the influence of pressure and heat, and secondary processing (finishing) is required.

As a joining method that eliminates the need for such secondary processing, laser welding has been adopted in various fields in recent years because it has little thermal influence on other parts than the joined part and can minimize deformation of the joined part. There is.

In an apparatus for laser-welding a circular member such as a round bar or a pipe, for example, a laser beam is applied to the abutting portion of the member while the member is rotated to perform welding. FIG. 9 shows a conventional structure of such a laser welding apparatus. The apparatus shown in FIG. 9 joins the cylindrical member 1 and the flanged cylindrical member 2 shown in FIG. 8, for example, and has the following configuration.

A hollow main shaft 4 is rotatably supported on the machine frame 3, and the main shaft 4 is rotationally driven by a motor 5 via a gear train 6. A rod 7 is supported in the main shaft 4 so as to be movable in the axial direction, and the rod 7 is reciprocated by an air cylinder 8. On the other hand, another air cylinder 9 is provided at a position facing the main shaft 4, and a pressing plate 10 is rotatably provided on the air cylinder 9.

The above-mentioned members 1 and 2 are fitted and held by the rod 7 projecting from the main shaft 4 by the advancing operation of the air cylinder 8, and the pressing plate 10 is pushed by the air cylinder 9 which has advanced.
Is pressed through the face plate 11 attached to the main shaft 4.

In this state, the motor 5 is activated and the main shaft 4 is driven to rotate, whereby both members 1 and 2 rotate.
Then, the laser beam output from the laser oscillator 12 is irradiated from the processing head 13 to the abutting portion of the members 1 and 2, and the members 1 and 2 are welded.

[0008]

By the way, in the case of joining two abutting end portions by laser welding while rotating the two members, the portion melted by receiving the laser beam loses heat to other portions. It cools and solidifies. Since the cooling of the melted portion is performed in a state of receiving the pressing force from the air cylinder 9, although it is a small amount, it does not work at the joint.
It is inevitable to bend in the shape of.

In this case, the size and material of the members to be joined,
It is preferable to change the pressing force of both members depending on the welding conditions such as the intensity of laser light, or to provide an appropriate gap at the end of both members. It is also possible to reduce the degree of bending in a V shape.

However, in the laser welding apparatus having the above-mentioned structure, the pressing force of the air cylinder 9 is fixedly determined by the size of the piston and the pressure of the compressed air supplied. Therefore, regardless of the size and material of the members to be joined and the welding conditions, the two members to be joined are always welded by the air cylinder 9 with a constant pressing force to perform the laser welding.

In order to solve such a problem, it is conceivable to replace the air cylinder 9 with an air cylinder with a brake. An air cylinder with a brake can stop its rod at a desired position by operating the brake, so it is possible to change the pressing force of both members to be joined or to provide a gap between both members. it can. However, in an air cylinder with a brake, depending on its structure, when the brake is actuated, the rod makes a small amount of advancing operation or retracting operation. The problem arises that the gap size deviates from the desired value.

The present invention has been made in view of the above circumstances, and an object thereof is to set a pressing force of both members to be joined or a gap provided between both members to a desired value. It is an object of the present invention to provide a laser welding device that can further reduce the degree of bending in a V shape.

[0013]

The laser welding apparatus of the present invention irradiates the ends of two members to be joined with a laser beam to perform welding, and is provided movably on a base body and driven by a motor. A moving table, a moving-side gripping device that is provided on the moving table and grips one member to be joined, a fixed-side gripping device that grips the other member that is attached to and joined to the base, and a moving amount of the moving table. A movement amount detecting means for detecting, a contact detecting means for detecting a time point when the one member comes into contact with the other member due to the movement of the moving table, and a contact between both members is detected by the contact detecting means. Control means for rotating the motor in the forward direction or in the reverse direction until the detected movement amount of the movement amount detection means reaches a set amount from the time point. .

[0014]

When the contact position of the two members is detected by the contact detecting means, the moving table is moved from the same position in one direction or the other direction. The moving amount of the moving table at this time is the amount until the moving amount detecting means detects that the moving amount has moved by the set amount from the abutting position of both members. The gap is accurately set to a preset amount.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In FIGS. 1 and 2, slide guides 22, 22 are provided on both sides of a base 21 of the laser welding apparatus, as shown in FIG.
A slide table 23 as a moving table is provided at 22 so as to be slidable in the left-right direction. The slide table 23 includes the nut 2 of the ball screw mechanism 24.
5 is fixed, and both ends of a screw rod 26 screwed to the nut 25 are rotatably supported by the base 21.
One end of the screw rod 26 is connected to a table drive motor 27 attached to the base body 21. Therefore, when the screw rod 26 is rotated in the forward direction or the reverse direction by the motor 27, the slide table 26 is accompanied with the rotation. 23 is arrow A
The slide movement is made in the direction of arrow B or in the opposite direction. A fixed table 28 is arranged on the right end side of the base 21. A moving side gripping mechanism 29 and a fixed side gripping mechanism 30 are provided on the slide table 23 and the fixed table 28, respectively.

First, the specific structure of the moving side gripping mechanism 29 will be described in detail with reference to FIG. 4. In the housing 31 attached to the upper portion of the slide table 23, the main shaft 32 and the bearing 33 are provided.
It is rotatably supported via. The main shaft 32 has a hollow shape, and a collet chuck 34 shown in FIG. 5 is accommodated inside the tip portion of the main shaft 32 so as to be movable in the axial direction. This collet chuck 34 is indicated by an arrow C in FIG.
When pressed in the direction indicated by, the tapered portion 3 on the inner surface of the main shaft 32
It contracts by moving to the smaller diameter side along 2a,
When the pressing force is released, the taper 32
It is configured to expand by moving along the a toward the larger diameter side.

The collet chuck 34 is pressed by the air cylinder mechanism 35. The air cylinder mechanism 35 includes a cylinder tube 36 attached to the housing 31 and a piston 37 provided in the cylinder tube 36, and compressed air is supplied into the cylinder tube 36 from a supply port 36a. Then, the piston 37 moves in the direction of arrow C.
On the other hand, a sleeve 38 is fitted on the outer side of the main shaft 32 so as to rotate integrally with the main shaft 32 and to move independently in the axial direction. And the piston 37 is indicated by the arrow C.
When the piston 37 moves in the direction,
The sleeve 38 is pressed and moved in the same direction via 9. The movement of the sleeve 38 is transmitted to the collet chuck 34 via a nut 40 attached inside the tip portion of the sleeve 38 and a collar 41 arranged between the nut 40 and the collet chuck 34.

As described above, the collet chuck 34 is pressed and moved in the direction of arrow C by the air cylinder mechanism 35, and is supplied from the supply port 36a to the cylinder tube 36.
When the compressed air is supplied to the piston 37 and the sleeve 38, the piston 37 and the sleeve 38 are moved in the direction opposite to the arrow C by the elastic force of the compression coil spring 40 to return to the original position. The pressure on 34 is released.

Next, the fixed side gripping mechanism 30 will be described with reference to FIG. 4. A main shaft 44 is rotatably supported via a bearing 45 in a housing 43 attached to the fixed table 28. The main shaft 44 is provided concentrically with the main shaft 32 of the moving-side gripping mechanism 29, and one end of the main shaft 44 has a guide member 46 having a tapered portion 46a on its inner peripheral surface.
Is attached. A blade 47 as a gripping body of the fixed-side gripping mechanism 30 is provided inside the guide member 46, and a blade 4 is operated by operating a lever (not shown).
When the blade 7 is moved along the tapered portion 46a toward the smaller diameter side indicated by the arrow D, the blade 47 contracts. On the contrary, when a blade (not shown) is operated to move the blade 47 to the larger diameter side along the tapered portion 46a, the blade 47 is expanded by its elastic restoring force.

The main shafts 32 and 41 of the first and second gripping mechanisms 26 and 27 are driven by a single main shaft drive motor 48 shown in FIG. That is, a ball spline shaft 49 constituting a drive mechanism is rotatably supported on the base 21 via a bearing 50, and the ball spline shaft 49 is connected to a main shaft drive motor 48 via a speed reducer 51. .

A ball spline bearing 52 that engages with the ball spline shaft 49 is attached to a housing 53 provided at the bottom of the slide table 23. Two ball spline bearings 52 are provided, and a first drive gear 54 is mounted between them. The first drive gear 54 is shown in FIG.
As shown in FIG.
1 meshes with the first drive gear 55 provided on the first
The drive gear 55 of is engaged with a first driven gear 56 provided on the main shaft 32. These first drive gear 54, first
The drive gear 55 and the first driven gear 56 constitute a first gear transmission mechanism 57 as a first transmission mechanism.

A second drive gear 58 is attached to the right end portion of the ball spline shaft 49, and the second drive gear 54 is a second drive gear 54 provided under the fixed table 28 shown in FIG. The second drive gear 59 meshes with the drive gear 59, and this second drive gear 59 meshes with a second driven gear 60 provided on the main shaft 44. The second driving gear 58, the second driving gear 59, and the second driven gear 60 constitute a second gear transmission mechanism 61 as a second transmission mechanism.

In this embodiment, two first and second intermediate gears 52 and 56 are provided. The two intermediate gears 52 and 56 are slightly deviated in the rotational direction, and the drive gears 51 and 55 and the driven gears 53 and 57 do not substantially backlash due to the deviation. As a result, the drive gear 5
Even if 1, 55 rotate in either forward or reverse directions, the driven gears 53, 57 start rotating without delay in time with respect to the rotation.

On the other hand, FIG. 6 is a block diagram showing an electrical configuration. In FIG. 6, a control device 62 as a control means is shown.
Is composed of a microcomputer. The control device 62 controls the table drive motor 27 and the spindle drive motor 48 via the motor drive circuits 63 and 64, and also controls the laser oscillator 65. The controller 62 includes a table drive motor 2
The detection signal from the load current detection circuit 66 that detects the load current of No. 7 and the detection pulse signal from the encoder 67 that detects the rotation speed of the screw rod 26 of the ball screw mechanism 24 that moves the slide table 23 are input. Has become. Further, the control device 62 sets whether to weld the two members 1 and 2 to be joined in a pressed state or in a state in which a gap is provided. In the former case, the pressing force is set, and in the latter case, the welding is performed. A setting signal from the setting device 68 for setting the gap size is input.

Here, when the slide table 23 moves in the direction of arrow A, when the cylindrical member 1 held by the moving side holding mechanism 29 comes into contact with the flanged cylindrical member 2 held by the fixed side holding mechanism 30, The load current of the table drive motor 27 increases. Therefore, the control device 62 compares the detected current of the load current detection circuit 66 with a reference value and determines that the time when the detected current exceeds the reference value is the time when both members 1 and 2 come into contact with each other. It is configured. Therefore, the controller 62
The load current detection circuit 66 and the load current detection circuit 66 act as contact detection means for detecting the time when the two members 1 and 2 contact each other. Further, the control device 62 is configured to detect the movement amount of the slide table 23 by counting the output pulses of the encoder 67, and thus the control device 62.
The encoder 67 and the encoder 67 act as a movement amount detection unit that detects the movement amount of the slide table 23.

In this case, when the slide table 23 further moves in the direction of arrow A from the point of contact between the members 1 and 2, the amount of movement of the slide table 23 between the members 1 and 2 due to the relationship between stress and strain. The pressing force according to the above will act. On the contrary, when the slide table 23 moves in the arrow B direction opposite to the arrow A, a gap having the same size as the movement amount is formed between the members 1 and 2.

Next, the control contents of the control device 62 in the above-mentioned configuration will be described with reference to the flow chart shown in FIG. It should be noted that the control content mainly relating to the movement of the slide table 23 is shown in FIG.

When the cylindrical member 1 and the flanged cylindrical member 2 are joined, it is first set by the setting device 69 whether the two members 1 and 2 are to be welded in a pressed state or in a state where a gap is provided. In the former case, the pressing force is set, and in the latter case, the gap size is set. Then, both members 1 and 2 are inserted into the collet chuck 34 and the blade 47, respectively, and then compressed air is supplied from the supply port 36a to move the collet chuck 34 in the direction of arrow C by the air cylinder mechanism 35 to form a cylindrical member. While holding 1
By operating a lever (not shown), the blade 47 is moved in the direction of arrow D to grip the flanged cylindrical member 2.

When the welding operation is started,
The table drive motor 27 starts forward rotation (step S
1) The forward rotation of the table drive motor 27 causes the slide table 23 to move in the arrow A direction. While the slide table 23 is moving in the direction of arrow A, the control device 62 is in a state of monitoring whether the detected current of the load current detection circuit 66 exceeds the reference value (step S).
2). Then, when the cylindrical member 1 comes into contact with the flanged cylindrical member 2, the load current of the table drive motor 27 increases and exceeds the reference value.
Determines that both members 1 and 2 have come into contact with each other (step S
Then, it is determined whether or not the setting content of the setting device 68 is "press and weld a member" (step S3).

When the setting content of the setting device 68 is "press and weld the member", "YE" is selected in step S3.
S ”, the output pulse of the encoder 67 is started to be counted while the table drive motor 27 is being rotated in the forward direction (steps S4 and S5:“ NO ”is repeated). When the count number of the output pulse of the encoder 67 reaches the set number corresponding to the pressing force set by the setter 68, in other words, the slide table 23 is moved by a certain amount from the time when the members 1 and 2 come into contact with each other. If only moved (“YES” in step S5), the table drive motor 27 stops. As described above, both members 1 and 2 are brought into a butted state with the set pressing force.

On the other hand, if the setting content of the setter 68 is "weld with a gap between members", step S
The answer is NO in 3, and the table drive motor 27 is stopped in the next step S8. Next, table drive motor 2
7 starts to rotate in reverse (step S10), moves the slide table 23 in the direction of arrow B, which is the reverse of the above, and starts counting output pulses of the encoder 67 (steps S4 and S5 repeat "NO"). . Then, when the count number of the output pulse of the encoder 67 reaches the set number corresponding to the gap dimension set by the setter 68, in other words, the slide table 23 is moved by a certain amount from the time when the members 1 and 2 come into contact with each other. If only moved (“YES” in step S5), the table drive motor 27 stops. As described above, a slight gap is created between the members 1 and 2.

Next, the control device 62 executes welding by laser light (step S7). This welding is performed while driving the spindle drive motor 48 and the laser oscillator 65. When the main shaft drive motor 48 is driven, its rotation is reduced by the speed reducer 51 and the ball spline shaft 49
And the shaft 49 rotates at a low speed. The rotation of the ball spline shaft 49 is the first
And transmitted to the main shafts 32 and 41 via the second gear transmissions 57 and 58, whereby the cylindrical member 1 and the flanged cylindrical member 2 rotate. In this state, the laser beam output from the laser oscillator 65 is also applied to both ends of the cylindrical members 1 and 2 from a processing head (not shown), and the both members 1 and 2 are welded.

In this case, the main shafts 32 and 41 of the first and second gripping mechanisms 26 and 27 gripping the two cylindrical members 1 and 2 are one ball spline shaft 49.
Since it is rotationally driven by the first and second gear transmission mechanisms 57 and 58, both main shafts 32 and 41, and thus both cylindrical members 1 and 2 rotate synchronously, and there is no risk of rotational deviation.

In the above embodiment, the ball spline shaft 49 and the ball spline bearing 52 allow the rotation of the spindle drive motor 48 to be transmitted to the first drive gear 54 regardless of the position of the slide table 23. When the members to be joined are limited and the moving range of the slide table 23 is small, the first drive gear 54 is fixed to an ordinary shaft, and the slide of the intermediate gear 52 with respect to the first drive gear 54 causes the slide table to slide. 23 may be allowed to move.

Further, in the above embodiment, the intermediate gears 52, 56
Drive gears 51, 55 and driven gear 5 as a set of two
Although the gears 3 and 57 are engaged with each other, one intermediate gear may be configured to allow backlash depending on the required welding accuracy.

Further, the transmission mechanism for transmitting the rotation of the spindle drive motor 48 to the spindles 32, 44 is not limited to the gear transmission mechanism, but a belt transmission mechanism including a toothed pulley and a toothed belt may be used. There are various possibilities.

[0038]

As described above, according to the present invention, the pressing force in the case where two members to be joined are butt-welded together, and the size of the gap in the case where a gap is provided between both members, the size of both members is Since the optimum value can be set according to the welding conditions such as the sheath material and the intensity of the laser beam, it is possible to further reduce the degree of bending of both members in a V shape. It is a thing.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

[Figure 2] Vertical side view

[Figure 3] Enlarged vertical section front view

FIG. 4 is an enlarged vertical side view of the gripping mechanism.

FIG. 5 is an enlarged perspective view of a collet chuck.

FIG. 6 is a block diagram showing an electrical configuration.

FIG. 7 is a flowchart showing control contents.

FIG. 8 is an enlarged perspective view of two members to be joined.

FIG. 9 is a vertical sectional side view showing a conventional configuration.

[Explanation of symbols]

Reference numeral 21 is a base, 23 is a slide table (moving table), 27 is a table drive motor, 28 is a fixed table, 29 is a moving side gripping mechanism, 30 is a fixed side gripping mechanism, 3
2 is a main shaft, 34 is a collet chuck, 35 is an air cylinder mechanism, 44 is a main shaft, 46 is a guide member, 47 is a blade, 48 is a main shaft drive motor, 54 is a first gear transmission mechanism, and 58 is a second gear transmission. A mechanism, 62 is a control device (contact detection means, movement amount detection means), 66 is load current detection means (contact detection means), and 67 is an encoder (movement amount detection means).

Claims (1)

[Claims] 1. In a laser welding apparatus for irradiating a laser beam to the ends of two members to be joined to perform welding, a moving table movably provided on a base body and driven by a motor, and a moving table provided on the moving table. A moving-side gripping device that grips one member to be joined, and a fixed-side gripping device that is attached to the base body and that grips the other member to be joined,
A moving amount detecting means for detecting a moving amount of the moving table, a contact detecting means for detecting a time when the one member comes into contact with the other member due to the movement of the moving table, and a contact detecting means for detecting both of them. A laser welding apparatus comprising: a control unit that rotates the motor in a forward direction or a reverse direction until a movement amount detected by the movement amount detection unit reaches a set amount from the time when the contact of the member is detected.