Seam Welding Equipment

Abstract

To detect a vertical position of a roller electrode in a movement range of the roller electrode, including a rolling section in which the roller electrode is rolled on at least part of one side of a work piece.SOLUTION: A seam-welding device 10 includes: roller electrodes 16R, 16L that perform seam welding on a work piece W by rolling on one side of an upper surface of a lid W2 of the work piece W; and a first drive mechanism 12 by which, while kept movable in a vertical direction, the roller electrodes 16R, 16L are moved relative to the work piece W, in a horizontal direction along the one side, and in a movement range including a rolling section in which the roller electrodes are moved on at least part of the one side. Further, the seam-welding device 10 includes position detection sensors 24R, 24L that detect vertical positions of the roller electrodes 16R, 16L when the roller electrodes 16R, 16L are moved in the movement range by the first drive mechanism 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a seam welding apparatus for performing seam welding using a roller electrode. [Background technology]

[0002] As disclosed in Patent Document 1, a seam welding device is known that rolls a roller electrode on one side of the upper surface of a workpiece to seam weld the workpiece. This seam welding device performs seam welding by moving the roller electrode in a direction along one side of the upper surface of the workpiece while being movable in the vertical direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-125835 A Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors of the present application conducted various studies on the above-mentioned conventional seam welding apparatus and found that if it is possible to detect the vertical position (position in the up-down direction) of the roller electrode in a range of movement of the roller electrode that includes a rolling section in which the roller electrode rolls on at least a part of one side of a workpiece, it is possible to perform better seam welding by using the detected position.

[0005] The present invention has been made in consideration of the above points, and has an objective of detecting the vertical position of a roller electrode within a movement range of the roller electrode that includes a rolling section in which the roller electrode rolls on at least a part of one side of a workpiece. [Means for solving the problem]

[0006] (1) In order to solve the above problems, a seam welding apparatus according to the present invention includes a roller electrode that rolls on one side of an upper surface of a workpiece to perform seam welding on the workpiece, a drive mechanism that moves the roller electrode in a vertically movable range of movement, the roller electrode being moved in a horizontal direction relative to the workpiece and along the one side, the range of movement including a rolling section in which the roller electrode rolls on at least a portion of the one side, and a vertical position detection sensor that detects the vertical position of the roller electrode when the roller electrode is moved within the range of movement by the drive mechanism.

[0007] (2) The vertical position detected by the vertical position detection sensor may be indicated by a distance traveled by the roller electrode in the vertical direction.

[0008] (3) The seam welding apparatus may further include a holding member that rotatably holds the roller electrode and is movable in an up-down direction together with the roller electrode, and a support member that supports the holding member so that it can be moved in an up-down direction, wherein the drive mechanism moves the roller electrode relative to the workpiece while the holding member is movable in an up-down direction relative to the support member, and the up-down position detection sensor detects the relative position of the holding member with respect to the support member as the up-down position of the roller electrode.

[0009] (4) The seam welding apparatus may further include a controller configured to control the drive mechanism and the application of voltage to the roller electrode for the seam welding, and a horizontal position detection sensor that detects the horizontal position of the roller electrode relative to the workpiece as a horizontal position, wherein the movement range includes a section where the roller electrode rides up on one side, and the controller identifies the horizontal position detected at a timing when the upward movement of the upward position ends based on the vertical positions detected sequentially by the vertical position detection sensor and the horizontal positions detected sequentially by the horizontal position detection sensor during a period when the roller electrode moved relatively within the movement range before the seam welding, and controls the drive mechanism and the application of voltage to the roller electrode to cause the roller electrode to perform the seam welding by ending the application of voltage to the roller electrode at an end position corresponding to the identified horizontal position.

[0010] (5) The seam welding apparatus may further include a controller configured to control the drive mechanism and the application of voltage to the roller electrode for the seam welding, and a horizontal position detection sensor that detects the horizontal position of the roller electrode relative to the workpiece as a horizontal position, wherein the movement range includes a section where the roller electrode falls from the one side, and the controller identifies the horizontal position detected at a timing immediately before the start of downward movement of the vertical position based on the vertical positions detected sequentially by the vertical position detection sensor and the horizontal positions detected sequentially by the horizontal position detection sensor during a period when the roller electrode moved relatively within the movement range before the seam welding, and controls the drive mechanism and the application of voltage to the roller electrode to cause the roller electrode to perform the seam welding by applying the voltage to the roller electrode up to an end position corresponding to the identified horizontal position.

[0011] (6) The welding machine may further include a controller that controls the drive mechanism and the roller electrode to cause the roller electrode to perform seam welding, and the controller may be configured to perform a predetermined process as a process to be performed when an abnormality occurs in the seam welding when the vertical position detected sequentially by the vertical position detection sensor falls outside a predetermined range during a period in which the seam welding is being performed. Effect of the Invention

[0012] According to the present invention, the vertical position detection sensor can detect the vertical position of the roller electrode in the movement range of the roller electrode, which includes the rolling section in which the roller electrode rolls on at least a part of one side of the workpiece. Furthermore, better seam welding can be performed by the configurations (4) to (6) based on the vertical positions detected in (1) to (3) above. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing a configuration of a seam welding device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing the positional relationship between the support member and the holding member in FIG. [Diagram 3] FIG. 3 is a diagram showing the positional relationship between the support member and the holding member in FIG. [Figure 4] FIG. 4 is a diagram showing the positional relationship between the support member and the holding member in FIG. [Diagram 5] FIG. 5 is a flowchart of a vertex position registration process executed by the controller of FIG. [Figure 6] FIG. 6 is a diagram showing how the roller electrode moves relative to the workpiece. [Figure 7] FIG. 7 is a diagram showing how the roller electrode rolls on one side of the workpiece. [Figure 8] FIG. 8 is a diagram showing how the roller electrode moves relative to the workpiece. [Figure 9] FIG. 9 is a flowchart of the seam welding process executed by the controller of FIG. [Figure 10] FIG. 10 is a diagram showing a support member to which a position detection sensor according to a modified example is attached, together with a holding member and a roller electrode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] A seam welding device 10 according to an embodiment of the present invention will now be described with reference to the drawings.

[0015] As shown in Fig. 1, the seam welding apparatus 10 is configured as a parallel seam welding apparatus that performs parallel seam welding on a cubic workpiece W placed on a stage 11 using a pair of roller electrodes 16R and 16L facing each other in the left-right direction. The workpiece W is composed of a package W1 that houses an electronic component such as a crystal, and a lid W2 that covers the opening of the package W1, and the lid W2 is parallel seam welded to the package W1. The parallel seam welding apparatus performs parallel seam welding on the top surface of the workpiece W, i.e., on two opposing sides out of the four sides of the top surface of the lid W2.

[0016] The seam welding apparatus 10 includes a stage 11, a first driving mechanism 12, a second driving mechanism 13, support members 14R and 14L, holding members 15R and 15L, and roller electrodes 16R and 16L.

[0017] The stage 11 has a surface extending in a horizontal direction including the front-rear and left-right directions. A carrier board 90 that holds a workpiece W is fixed to the surface of the stage 11. The workpiece W is placed on the stage 11 by being fitted into and fixed in a recess 90A provided in the carrier board 90.

[0018] The first driving mechanism 12 moves and rotates the stage 11, thereby moving and rotating the roller electrodes 16R and 16L arranged above the stage 11 relative to the stage 11 and the workpiece W. For such relative movement and rotation, the first driving mechanism 12 is configured to be able to move the stage 11 in two axial directions, that is, forward / backward and left / right directions, and rotate the stage 11 about an axis passing through the center of the upper surface of the stage 11 in the up / down direction. The specific configuration of the first driving mechanism 12 is arbitrary. For example, the first driving mechanism 12 has a turntable that rotates the stage 11, a first moving device that moves the turntable left and right by a ball screw and a motor, etc., and a second moving device that moves the first moving device back and forth by a ball screw and a motor, etc.

[0019] The second drive mechanism 13 drives the support members 14R and 14L to move them in the up-down direction. Furthermore, the second drive mechanism 13 can also move each of the support members 14R and 14L individually in the left-right direction. As described below, the support member 14R supports a holding member 15R that holds the roller electrode 16R, and the support member 14L supports a holding member 15L that holds the roller electrode 16L. Therefore, the second drive mechanism 13 moves the roller electrodes 16R and 16L and the holding members 15R and 15L via the support members 14R and 14L.

[0020] The second drive mechanism 13 includes a motor 13A, a ball screw 13B operated by the motor 13A to move the support members 14R and 14L in the vertical direction, and linear motors 13R and 13L to move the support members 14R and 14L in the horizontal direction, respectively.

[0021] The ball screw 13B includes a screw shaft 13BA that extends in the vertical direction and is rotated by the motor 13A, and a nut 13BB that is screwed into the screw shaft 13BA via a steel ball (not shown). The nut 13BB moves in the vertical direction as the screw shaft 13BA rotates. The nut 13BB may be configured to move, for example, on a guide rail that extends in the vertical direction so as not to rotate together with the screw shaft 13BA.

[0022] Although not shown directly, linear motors 13R and 13L are fixed to the right and left sides of nut 13BB, respectively. Linear motors 13R and 13L include a stator 13RA fixed to the right side of nut 13BB and extending in the left-right direction, and a slider 13RB that moves in the left-right direction on stator 13RA. Linear motor 13L includes a stator 13LA extending in the left-right direction, and a slider 13LB that moves in the left-right direction on stator 13LA.

[0023] Support members 14R and 14L are fixed to the movers 13RB and 13LB, respectively. Therefore, the linear motors 13R and 13L move the support members 14R and 14L in the left-right direction, respectively, independently of each other.

[0024] As described above, the linear motor 13R is fixed to the nut 13BB. That is, the support member 14R is fixed to the nut 13BB via the linear motor 13R, and the support member 14L is fixed to the nut 13BB via the linear motor 13L. Therefore, when the nut 13BB moves in the vertical direction, the support members 14R and 14L also move in the vertical direction.

[0025] With the above-mentioned configuration, the second driving mechanism 13 can move the support members 14R and 14L in the up-down direction by moving the nut 13BB of the ball screw 13B in the up-down direction by the motor 13A. Furthermore, the second driving mechanism 13 can move the support members 14R and 14L in the left-right direction by the linear motor 13R and the linear motor 13L.

[0026] The support member 14R supports a holding member 15R which holds a roller electrode 16R. Here, a middle part 15RB of the holding member 15R passes through a through hole 14RA of the support member 14R, thereby supporting the holding member 15R. The roller electrode 16R is held by a lower end part 15RA of the holding member 15R so as to be rotatable with the axial direction of the rotation shaft as the left-right direction.

[0027] The middle portion 15RB of the holding member 15R extends in the vertical direction, passes through the through hole 14RA of the support member 14R, and is slidable along the inner surface of the through hole 14RA. That is, the holding member 15R moves in the vertical direction relative to the support member 14R.

[0028] The upper end 15RC of the holding member 15R is connected to the middle portion 15RB and protrudes horizontally beyond the middle portion 15RB. Therefore, the upper end 15RC cannot pass through the through hole 14RA. This prevents the holding member 15R from falling off the support member 14R because the upper end 15RC acts as a retainer. The upper end 15RC also functions as a weight and biases the holding member 15R downward.

[0029] Similarly to the support member 14R and the holding member 15R, the support member 14L supports the holding member 15L. The lower end 15LA of the holding member 15L holds the roller electrode 16L rotatably with the axial direction of the rotation shaft as the left-right direction. Furthermore, the holding member 15L also includes a middle part 15LB that passes through the through hole 14LA of the support member 14L and is slidable against the inner surface of the through hole 14LA, and an upper end 15LC that functions as a retainer for the weight and the support member 14L.

[0030] As described above, the supporting members 14R and 14L support the holding members 15R and 15L, so that the holding members 15R and 15L and the roller electrodes 16R and 16L held by them move together with the supporting members 14R and 14L.

[0031] Here, the vertical positional relationship between the support members 14R and 14L, the holding members 15R and 15L, and the roller electrodes 16R and 16L will be described with reference to FIGS.

[0032] 2, when the support members 14R and 14L are located in the upper position by the second driving mechanism 13, the roller electrodes 16R and 16L do not contact the workpiece W. At this time, the upper ends 15RC and 15LC of the holding members 15R and 15L are hooked onto the support members 14R and 14L.

[0033] As shown in Fig. 3, when the support members 14R and 14L move downward, the holding members 15R and 15L also move downward, and the roller electrodes 16R and 16L (specifically, working ends 16RA and 16LA, which will be described later) come into contact with the workpiece W. Thereafter, as shown in Fig. 4, when the support members 14R and 14L move further, the workpiece W pushes the holding members 15R and 15L relatively upward via the roller electrodes 16R and 16L. In other words, the holding members 15R and 15L move upward relative to the support members 14R and 14L. In the state shown in Fig. 4, the holding members 15R and 15L press the roller electrodes 16R and 16L against the workpiece W by their own weight.

[0034] In this way, the holding member 15R moves vertically together with the roller electrode 16R relative to the support member 14R. Similarly, the holding member 15L moves vertically together with the roller electrode 16L relative to the support member 14L.

[0035] The roller electrodes 16R and 16L shown in FIG. 1 parallel seam weld the lid W2 of the work W to the package W1. The roller electrodes 16R and 16L face each other with a gap in the left-right direction. The roller electrodes 16R and 16L have working ends 16RA and 16LA, respectively, which are frustum-shaped, at the ends of the roller electrodes facing each other. During welding, the tapered sides of the working ends 16RA and 16LA come into contact with two sides of the top surface of the work W, i.e., the lid W2, respectively. During welding, the roller electrodes 16R and 16L are moved relatively in the front-rear direction by the first drive mechanism 12 while continuously energizing the roller electrodes 16R and 16L. As a result, the working ends 16RA and 16LA roll on the two sides, respectively, and sequentially heat the contact points with the lid W2. This allows parallel seam welding to be performed.

[0036] In addition to the above configuration, the seam welding apparatus 10 includes, as components constituting a control system, position detection sensors 21-24L, a controller 25, a storage unit 26, and an input / output device 27. In Fig. 1, the position detection sensors 21-23L are depicted as schematic blocks, and their actual positions are not reflected in Fig. 1.

[0037] The position detection sensor 21 is, for example, arranged in the first driving mechanism 12, and is composed of two rotary encoders or linear encoders that detect the front-rear and left-right positions of the stage 11. Such a position detection sensor 21 is configured as a horizontal position detection sensor that detects the horizontal positions of the roller electrodes 16R and 16L relative to the stage 11 and further to the workpiece W on the stage 11 by detecting the position of the stage 11. The position detection sensor 22 is, for example, composed of a linear encoder that detects the vertical position (support members 14R and 14L) of the nut 13BB. The position detection sensor 22 may be composed of a rotary encoder arranged in or outside the motor 13A, and detects the rotational position and number of rotations of the motor 13A or the screw shaft 13BA to detect the position of the nut 13BB.

[0038] The position detection sensor 23R is, for example, arranged in the linear motor 13R, and is composed of a linear encoder that detects the left-right positions of the moving element 13RB and the support member 14R. The position detection sensor 23L is, for example, arranged in the linear motor 13L, and is composed of a linear encoder that detects the left-right positions of the moving element 13LB and the support member 14L.

[0039] As shown in Figs. 2 to 4, the position detection sensor 24R is a linear encoder having a scale 24RA provided on the holding member 15R and a sensor 24RB attached to the lower surface of the support member 14R to read information on the scale 24RA. The position detection sensor 24R detects the relative positions of the holding member 15R and the roller electrode 16R with respect to the support member 14R in the vertical direction. The position detection sensor 24L is a linear encoder having a scale 24LA provided on the holding member 15L and a sensor 24LB attached to the lower surface of the support member 14L, similar to the position detection sensor 24R. The position detection sensor 24L detects the relative positions of the holding member 15L and the roller electrode 16L with respect to the support member 14L in the vertical direction. In this way, the position detection sensors 24R and 24L are configured as vertical position detection sensors that detect the vertical positions of the roller electrodes 16R and 16L, respectively.

[0040] The controller 25 is configured with a computer such as a microcomputer, a PLC (Programmable Logic Controller), etc. The storage unit 26 stores programs and the like executed by the controller 25. The storage unit 26 may be configured as a memory included in the controller 25. The input / output device 27 is configured with a user interface such as a touch panel, and receives information input from a user, supplies the received information to the controller 25, and outputs information from the controller 25 to the outside.

[0041] The controller 25 is configured to control the first drive mechanism 12 and the second drive mechanism 13 to perform seam welding, and to control the application of voltage for seam welding to the roller electrodes 16R and 16L. For example, the controller 25 includes a power supply circuit that converts power from a power supply (not shown) into power for welding and supplies it to the roller electrodes 16R and 16L, and controls the application of voltage for seam welding to the roller electrodes 16R and 16L (whether or not to apply voltage, the voltage value of the voltage to be applied, etc.) by the power supply circuit. When the roller electrodes 16R and 16L to which the voltage is applied come into contact with the workpiece W, a welding current flows therethrough, and the roller electrodes 16R and 16L are energized. In this state, the roller electrodes 16R and 16L roll to perform seam welding. Various parameters for performing seam welding and the detection results of the position detection sensors 21 to 24L are also input to the controller 25 via the input / output device 27. The controller 25 performs seam welding by feedback control or servo control of the first drive mechanism 12 etc. based on the input detection results. The specific details of the seam welding will be described later.

[0042] The controller 25 executes a vertex position registration process for registering the positions of the four vertices (one end and the other end of each edge of the top surface) of the top surface of the workpiece W in the memory unit 26 before welding, and a seam welding process for performing seam welding based on the registered positions of the four vertices. The positions of the four vertices are identified based on the positions of the roller electrodes 16R and 16L as described below, and the positions of the four vertices are identified by the XYZ coordinates set on the stage 11 together with the positions of the roller electrodes 16R and 16L. Below, the XYZ coordinates will be explained first, and then each of the above processes will be explained.

[0043] On stage 11, mutually orthogonal X-, Y-, and Z-axes are set for the above-mentioned XYZ coordinates. In Fig. 1, the X-axis direction is the front-rear direction and the Y-axis direction is the left-right direction, but when stage 11 is rotated 90 degrees from the state in Fig. 1 by first driving mechanism 12, the X-axis direction becomes the left-right direction and the Y-axis direction becomes the front-rear direction (see also Fig. 8). The XYZ coordinates of roller electrodes 16R and 16L have an origin when first driving mechanism 12 and second driving mechanism 13 are in a predetermined initial state.

[0044] When the stage 11 is moved by the first driving mechanism 12, the roller electrodes 16R and 16L move relative to the stage 11. The XY coordinates of the XYZ coordinates of the roller electrodes 16R and 16L are specified by the amount of movement in the front-back and left-right directions from the initial position of the stage 11 to its current position, and the amount of movement in the left-right direction of the roller electrodes 16R and 16L from their initial positions to their current positions. The controller 25 specifies each of the amounts of movement from the detection results of the position detection sensor 21 and the position detection sensors 23R and 23L, and specifies Pr(X,Y), which is the XY coordinate of the roller electrode 16R, and Pl(X,Y), which is the XY coordinate of the roller electrode 16L, from the specified results.

[0045] Pr(Z), which is the Z coordinate of roller electrode 16R, is determined by the amount of movement of support member 14R from the initial position to the current position and the amount of movement of holding member 15R relative to support member 14R. Similarly, the Z coordinate of roller electrode 16L is determined by the amount of movement of support member 14L and the amount of movement of holding member 15L relative to support member 14L. Controller 25 determines each of the amounts of movement from the detection results of position detection sensor 22 and position detection sensors 24R and 24L, and determines Pr(Z) and Pl(Z) from the determined results.

[0046] The coordinates Pr(X,Y,Z) and Pl(X,Y,Z) are periodically and sequentially specified based on the detection results from the position detection sensors 21 to 24L.

[0047] Next, a vertex position registration process for registering the positions of the four vertices on the top surface of the workpiece W in the memory unit 26 before welding will be described with reference to Fig. 5. The controller 25 executes the vertex position registration process by executing a program stored in the memory unit 26. In the following description, the four vertices on the top surface of the workpiece W will also be referred to as vertices V1 to V4, as shown in Fig. 6.

[0048] In the vertex registration process shown in Fig. 5, the controller 25 first controls the first driving mechanism 12 and the second driving mechanism 13 to transition them to a first initial state (step S101). As a result, the stage 11 and the roller electrodes 16R and 16L are moved to a first initial position. Note that the first initial position at this time is a position where the X-axis direction of the stage 11 is the front-rear direction as shown in Fig. 1. Although not shown in Fig. 5, after step S101, the controller 25 monitors the XYZ coordinates of the roller electrodes 16R and 16L with the first initial position as the origin based on the detection results from the position detection sensors 21 to 24L.

[0049] Thereafter, the controller 25 moves each of the roller electrodes 16R and 16L to a first registration start position (step S102). The first registration start position is a relative position with respect to the stage 11. The first registration start position is input by the user via the input / output device 27, for example. The first registration start position is a position where the roller electrodes 16R and 16L can ride up onto vertices V1 and V2, which are one end of two opposing sides of the workpiece W, respectively, when the roller electrodes 16R and 16L are moved from the position in the forward / backward direction relative to the stage 11 by the first driving mechanism 12, as shown in Figs. 6 and 7. The controller 25 controls the first driving mechanism 12 and the second driving mechanism 13 to move the stage 11 and the support members 14R and 14L, thereby moving the roller electrodes 16R and 16L to the first registration start position. The movement of the roller electrodes 16R and 16L to the first registration start position may be performed by the user manually moving the stage 11 and the support members 14R and 14L.

[0050] After step S102, the controller 25 controls the first driving mechanism 12 to move the stage 11 a predetermined distance in the forward and backward directions (step S103). As a result, the roller electrodes 16R and 16L move a predetermined distance in the forward and backward directions relative to the stage 11. The predetermined distance is a distance that allows the working end 16RA of the roller electrode 16R and the working end 16LA of the roller electrode 16L (not shown in FIG. 7) to ride up on two opposing sides of the workpiece W from vertices V1 and V2, respectively, to roll, and then to fall from vertices V3 and V4, respectively, as shown in FIG. 6 and FIG. 7. The end position of the predetermined distance is detected by, for example, the controller 25. The controller 25 monitors whether the Z coordinates of the roller electrodes 16R and 16L continue to descend and whether the total distance of the descent has reached or exceeded a predetermined threshold value. When the total distance of the descent reaches or exceeded a predetermined threshold value, it can be said that the working end 16RA and the working end 16LA have fallen from vertices V1 and V3, as described later. In this case, the controller 25 determines that the stage 11 has been moved to the end position of the predetermined distance, and ends control of moving the stage 11. The predetermined distance may be input by a user. The movement of the stage 11 in step S103 may be performed manually by a user. In step S103, the controller 25 sequentially records in the memory unit 26 the XZ coordinates Pr(X,Z) and Pl(X,Z) of the XYZ coordinates of the roller electrodes 16R and 16L during the movement of the stage 11 by the above-mentioned control or manual operation.

[0051] After step S103, the controller 25 identifies the XZ coordinates of the four vertices of the upper surface of the workpiece W based on Pr(X,Z) and Pl(X,Z) sequentially recorded in the memory unit 26 (step S104).

[0052] 7, when the roller electrode 16R rides on the vertex V1 of the workpiece W, its central axis describes a circular locus with the vertex V1 as its center and R as its radius. Here, R is the radius of the circumference of the working end 16RA of the roller electrode 16R that contacts the vertex V1. However, the side surface of the working end 16RA is tapered, and it is not known which part of the taper contacts the vertex V1, so the above-mentioned R is an unknown value.

[0053] The controller 25 identifies a section in which the coordinate Z rises and Pr(X,Z) describes a circular locus among the Pr(X,Z) sequentially recorded in the storage unit 26. The section in which the circular locus is described is identified, for example, by plotting Pr(X,Z) on an XZ coordinate plane and pattern matching with a template image of a circular arc. In addition, the position of the central axis of the roller electrode 16R usually does not fluctuate significantly except when it climbs onto the workpiece W or falls off. Even if there is a fluctuation, it is merely a minute unevenness due to a dimensional error of the side of the workpiece W. For this reason, the controller 25 may identify, as a section in which the coordinate Z continues to rise and the total distance of the rise is equal to or greater than a predetermined threshold, among the Pr(X,Z) sequentially recorded, as a section in which the circular locus is formed. The controller 25 extracts three coordinates Pr(X1,Z1) to Pr(X3,Z3) as shown in FIG. 7 from Pr(X,Z) constituting the section in which the circular locus is formed. The three points Pr are extracted, for example, randomly. Thereafter, the controller 25 solves the simultaneous equations consisting of three equations obtained by substituting the three extracted coordinates for X and Z in the following equation (1), and identifies the coordinates V1(Xa, Za) of the vertex V1. (X-Xa) 2 +(Z-Za) 2 =R 2 (1)

[0054] The coordinate V2(Xb, Zb) of the vertex V2 on which the roller electrode 16L rides is the same as the coordinate of the vertex V1, so the controller 25 specifies Xa and Za of the coordinate A as the coordinate V2(Xb, Zb) of the vertex V2. The coordinate V2(Xb, Zb) of the vertex V2 may be specified independently by a method similar to that described above.

[0055] Furthermore, as shown in FIG. 7, when the roller electrode 16R falls from the vertex V3 of the workpiece W, its central axis describes a circular locus with the vertex V3 as the center and R as the radius. For this reason, the controller 25 identifies a section in which the coordinate Z descends and Pr(X,Z) describes a circular locus among the Pr(X,Z) sequentially recorded in the storage unit 26. The identification of the section may be performed by the above-mentioned template matching. Also, among the sequentially recorded Pr(X,Z), a section in which the coordinate Z continues to descend and the total distance of descent is equal to or greater than a predetermined threshold may be identified as a section of a circular locus. The controller 25 extracts three coordinates Pr(X4,Z4) to Pr(X6,Z6) as shown in FIG. 7 from Pr(X,Z) constituting a section in which the coordinate Z descends and describes a circular locus. The three Pr points are extracted, for example, randomly. Thereafter, the controller 25 solves the simultaneous equations consisting of three equations obtained by substituting the three extracted coordinates for X and Z in the above equation (1), and identifies the coordinates V3(Xc, Zc) of the vertex V3.

[0056] In the same manner as above, the controller 25 also identifies the coordinates V4(Xd, Zd) of the vertex V4 of the workpiece W on which the roller electrode 16L has fallen, based on Pl(X, Z) sequentially recorded in the memory unit .

[0057] After that, the controller 25 registers the coordinates V1(Xa, Za) to V4(Xd, Zd) of the vertices V1 to V4 identified above in the storage unit 26 (step S105).

[0058] Thereafter, the controller 25 controls the first driving mechanism 12 and the second driving mechanism 13 to move the roller electrodes 16R and 16L upward and rotate the stage 11 by 90 degrees, transitioning them to the second initial state (step S106). As a result, the stage 11 and the roller electrodes 16R and 16L are moved to the second initial position. Note that the second initial position at this time is a position where the Y-axis direction of the stage 11 is the front-rear direction, as shown in FIG. 8. Although not shown in FIG. 5, after step S107, the controller 25 monitors the XYZ coordinates of the roller electrodes 16R and 16L with the second initial position as the origin, based on the detection results from the position detection sensors 21 to 24L.

[0059] Thereafter, the controller 25 moves each of the roller electrodes 16R and 16L to the second registration start position (step S107). The second registration start position is a relative position with respect to the stage 11. The second registration start position is input by the user via the input / output device 27, for example. The second registration start position is a position where the roller electrodes 16R and 16L can ride up onto the vertices V2 and V4 of the two opposing sides of the workpiece W, respectively, when the roller electrodes 16R and 16L are moved from the position in the forward / backward direction relative to the stage 11 by the first driving mechanism 12, as shown in FIG. 8. The controller 25 controls the first driving mechanism 12 and the second driving mechanism 13 to move the stage 11 and the support members 14R and 14L, thereby moving the roller electrodes 16R and 16L to the second registration start position. The movement of the roller electrodes 16R and 16L to the second registration start position may be performed by the user manually moving the stage 11 and the support members 14R and 14L.

[0060] After step S107, the controller 25 controls the first driving mechanism 12 to move the stage 11 a predetermined distance in the forward and backward directions (step S108). As a result, the roller electrodes 16R and 16L move a predetermined distance in the forward and backward directions relative to the stage 11. The predetermined distance is a distance that allows the working end 16RA of the roller electrode 16R and the working end 16LA of the roller electrode 16L to climb onto two opposing sides of the workpiece W from vertices V2 and V4, respectively, roll, and then drop from vertices V1 and V3, respectively. The end positions of the predetermined distance are detected, for example, by the controller 25, as in step S103. The predetermined distance may be input by the user. The movement of the stage 11 in step S108 may be performed manually by the user. In step S108, the controller 25 sequentially records in the memory unit 26 the YZ coordinates Pr(Y,Z) and Pl(Y,Z) of the XYZ coordinates of the roller electrodes 16R and 16L while the stage 11 is being moved by the above-mentioned control or manual operation.

[0061] After step S108, the controller 25 determines the YZ coordinates of the four vertices V1 to V4 on the top surface of the workpiece W based on Pr(Y,Z) and Pl(Y,Z) sequentially recorded in the memory unit 26 (step S109). The YZ coordinates of the four vertices V1 to V4 can be determined in the same manner as the determination of the XZ coordinates described above (replace the X coordinate with the Y coordinate), and so details will be omitted.

[0062] Thereafter, the controller 25 registers the coordinates V1(Ya, Za) to V4(Yd, Zd) of the vertices V1 to V4 identified above in the storage unit 26 (step S110), and ends the vertex registration process.

[0063] After the vertex registration process is completed, the controller 25 executes the seam welding process shown in Fig. 9. In the seam welding process, the controller 25 first reads out the coordinates V1(Xa,Za)-V4(Yd,Zd) of the vertices V1-V4 registered in the storage unit 26 in the vertex registration process (step S201). After that, the controller 25 controls the first driving mechanism 12 and the second driving mechanism 13 to transition them to a first initial state (step S202).

[0064] Thereafter, the controller 25 controls the first driving mechanism 12 and the second driving mechanism 13 to move the roller electrodes 16R and 16L to the first welding start position based on the coordinates of the vertex V1 or V2 (step S203). The first welding start position is Xa or Xb, which is the X coordinate of the vertex V1 or V2, and is a position where the vertical positions of the support members 14R and 14L, i.e., the nuts 13BB, and the horizontal positions of the support members 14R and 14L are the same as the first registration start position. With such a position, the roller electrodes 16R and 16L at the first welding start position are positioned to contact the vertices V1 and V2 on the top surface of the workpiece W (see the position of the roller electrode 16R indicated by the solid line on the right side of FIG. 7).

[0065] Thereafter, the controller 25 performs seam welding with the roller electrodes 16R and 16L until the roller electrodes 16R and 16L reach the first welding end position (step S204). The first welding end position is the position of the X coordinate Xc or Xd of the vertex V3 or V4 registered above, and the YZ coordinates do not change. The controller 25 applies a voltage to the roller electrodes 16R and 16L to energize them, while controlling the first drive mechanism to move the stage 11 so that the roller electrodes 16R and 16L roll to the position of the first welding end position. At this time, the controller 25 monitors whether or not the relative positions of the holding member 15R and the roller electrode 16R to the support member 14R in the vertical direction are outside a predetermined range based on the detection result from the position detection sensor 24R. For example, the controller 25 monitors whether or not the current relative position based on the detection result is outside a specific range based on the relative position at the first welding start position. For example, if the workpiece W jumps out of the recess 90A of the carrier board 90 for some reason, the vertical positions of the holding member 15R and the roller electrode 16R will change significantly while the roller electrode 16R is rolling. In such a case, the relative position will be outside the predetermined range, and the controller 25 will perform processing such as outputting information about an abnormality to the input / output device 27. The controller 25 also performs the above-mentioned monitoring of the holding member 15L and the roller electrode 16L.

[0066] Thereafter, the controller 25 controls the first driving mechanism 12 and the second driving mechanism 13 to move the roller electrodes 16R and 16L upward and rotate the stage 11 by 90 degrees, thereby transitioning them to the second initial state (step S205).

[0067] Thereafter, the controller 25 controls the first driving mechanism 12 and the second driving mechanism 13 to move the roller electrodes 16R and 16L to the second welding start position based on the coordinates of the vertex V2 or V4 (step S206). The second welding start position is Yb or Yd, whose Y coordinate is the Y coordinate of the vertex V2 or V4, and the vertical positions of the support members 14R and 14L, i.e., the nut 13BB, and the horizontal positions of the support members 14R and 14L are the same as the second registration start position. With such a position, the roller electrodes 16R and 16L at the second welding start position are positioned to contact the vertices V2 and V4 of the upper surface of the workpiece W, respectively.

[0068] Thereafter, the controller 25 performs seam welding with the roller electrodes 16R and 16L until the roller electrodes 16R and 16L reach the second welding end position (step S207). The second welding end position is the Y coordinate Ya or Yc of the vertex V1 or V3 registered above, and the XZ coordinates do not change. The controller 25 applies a voltage to the roller electrodes 16R and 16L to energize them, while controlling the first drive mechanism to move the stage 11 so that the roller electrodes 16R and 16L roll to the second welding end position. At this time, the controller 25 monitors whether the relative positions of the holding member 15R and the roller electrode 16R with respect to the support member 14R in the vertical direction are outside a predetermined range based on the detection result from the position detection sensor 24R, as described above.

[0069] As described above, in this embodiment, the first drive mechanism 12 moves the roller electrodes 16R and 16L in a state in which they can move in the vertical direction, in a horizontal direction along one side of the upper surface of the workpiece W relative to the workpiece W, in a movement range including a rolling section in which the roller electrodes roll on the side. Position detection sensors 24R and 24L are provided to detect the vertical positions of the roller electrodes 16R and 16L when the roller electrodes 16R and 16L move in the movement range. This makes it possible to detect the vertical positions of the roller electrodes 16R and 16L moving in a movement range including a rolling section in which the roller electrodes roll on the side. In particular, in this embodiment, the above-mentioned apex position registration process can be performed based on the vertical positions, and further, abnormality detection in the seam welding process can also be performed, so that better seam welding can be performed.

[0070] In the apex position registration process, it is sufficient to identify the positions where the roller electrodes 16R and 16L climb onto and fall off the workpiece W. Therefore, the first driving mechanism 12 may move the roller electrodes 16R and 16L so that they roll only on a part of one side of the workpiece W (both ends).

[0071] The position detection sensors 24R and 24L may be optical distance sensors that detect distance based on the timing of receiving reflected light. In this case, the position detection sensors 24R and 24L may be attached to the roller electrodes 16R and 16L or the holding members 15R and 15L, etc., and detect the vertical positions of the roller electrodes 16R and 16L by detecting the distance to a predetermined member that does not move in the vertical direction during the movement of the roller electrodes 16R and 16L, such as a member that supports the workpiece W, such as the stage 11 or the carrier board 90.

[0072] In the above embodiment, the vertical positions of the roller electrodes 16R and 16L detected by the position detection sensors 24R and 24L are indicated by the distances of movement of the roller electrodes 16R and 16L in the vertical direction relative to the support members 14R and 14L, respectively. This makes it possible to detect the movement of the roller electrodes 16R and 16L relative to the support members 14R and 14L. The position detection sensors 24R and 24L may be configured with a motion sensor or the like that detects the amount of movement from a predetermined reference position by detecting acceleration or the like.

[0073] In this embodiment, the roller electrodes 16R and 16L are rotatably held by holding members 15R and 15L that can move vertically together with the roller electrodes 16R and 16L, and support members 14R and 14L that support the holding members 15R and 15L so that they can move vertically. Furthermore, the first drive mechanism 12 moves the roller electrodes 16R and 16L relative to the workpiece W in a state in which the holding members 15R and 15L can move vertically relative to the support members 14R and 14L. The position detection sensors 24R and 24L detect the relative positions of the holding members 15R and 15L with respect to the support members 14R and 14L as the vertical positions of the roller electrodes 16R and 16L. This allows the positions of the roller electrodes 16R and 16L to be detected in a better manner.

[0074] The position detection sensors 24R and 24L may be optical distance sensors 124R and 124L that are provided on the lower surfaces of the support members 14R and 14L, respectively, as shown in FIG. 10, and detect the vertical distance between the lower ends 15RA and 15LA of the holding members 15R and 15L. The position detection sensors 124R and 124L detect the vertical positions of the roller electrodes 16R and 16L by detecting the distance based on the timing of receiving reflected light. The position detection sensors 124R and 124L may be provided on the upper surfaces of the support members 14R and 14L, respectively, and measure the distance between the upper ends 15RC and 15LC. The position detection sensors 124R and 124L may also be provided on the holding members 15R and 15L to detect the distance between the support members 14R and 14L. The object of distance detection by these position detection sensors may be a member that moves integrally with the member on which the position detection sensors are provided. For example, when the target is the stage 11, the location of the light reflecting surface changes with the movement of the stage 11, and if the stage 11 has irregularities such as dimensional errors, the detection distance may change depending on the location of the reflecting surface. On the other hand, by making the target for distance detection a member that moves integrally with the member on which the position detection sensor is provided, the reflecting surface can always be in the same location, thereby preventing the above-mentioned inconvenience.

[0075] Furthermore, in this embodiment, the positions of the vertices V1 to V4 of the workpiece W are identified by the vertical positions (Z coordinate) and horizontal positions (X coordinate or Y coordinate) of the roller electrodes 16R and 16L in the vertex position registration process, and welding is performed based on these positions, thereby achieving precise welding.

[0076] The welding start position during the seam welding includes a movement start position where the roller electrodes 16R and 16L start moving to perform seam welding, and a voltage application start position where the application of voltage starts. Similarly, the welding end position includes a movement end position where the movement of the roller electrodes 16R and 16L ends after seam welding ends, and a voltage application end position where the application of voltage ends. In the above embodiment, the X-coordinate or Y-coordinate positions of the vertices V1 to V4 are the movement start position and the voltage application start position, or the movement end position and the voltage application end position. However, each of the above positions may be positions shifted from the positions of the vertices V1 to V4. For example, the movement start position and the voltage application start position may be in front of the vertices V1 and V2 (FIG. 6) or the vertices V2 and V4 (FIG. 8) of the workpiece W in the moving direction of the roller electrodes 16R and 16L. The movement start position and the voltage application start position may be different positions. For example, only the movement start position and the voltage application start position may be the front position, and the latter may be the positions of vertices V1 and V2 (FIG. 6) or vertices V2 and V4 (FIG. 8). The movement end position and the voltage application end position may be the back side of vertices V3 and V4 (FIG. 6) or vertices V1 and V3 (FIG. 8) of the workpiece W in the advancing direction of the roller electrodes 16R and 16L. The movement end position and the voltage application end position may be different positions. For example, only the movement end position and the voltage application end position may be the back side, and the latter may be the positions of vertices V3 and V4 (FIG. 6) or vertices V1 and V3 (FIG. 8). The above four positions may be positions that have a predetermined relationship with the positions of vertices V1 to V4 registered in the vertex position registration process (for example, the same position or a position shifted by a predetermined distance). In this way, precise welding is achieved by performing seam welding based on the movement start position, voltage application start position, movement end position, and voltage application end position that correspond to the positions of the identified vertices V1 to V4.

[0077] In the apex position registration process and seam welding, the support members 14R and 14L do not move up and down. Therefore, the Z coordinate, which is the vertical position of the roller electrodes 16R and 16L, is the relative movement amount with respect to the support members 14R or 14L. For this reason, only the latter relative movement amount may be used to specify the Z coordinate, between the movement amount from the initial position to the current position of the support members 14R and 14L and the relative movement amount of the holding members 15R and 15L with respect to the support members 14R and 14L.

[0078] The controller 25 does not need to use the above formula (1) to specify the X-coordinate or Y-coordinate of the vertices V1 to V4. According to Fig. 7, the position where the roller electrode 16R climbs onto the workpiece W (i.e., vertex V1) is the position at the end timing when the roller electrode 16R finishes rising, so this position may be the position of the vertex V1. In this way, the controller 25 may determine the horizontal position (X-coordinate or Y-coordinate) at the end timing (Fig. 7) of the upward movement of the roller electrodes 16R and 16L (particularly, when they continue to rise for a predetermined distance or more) as the position of the vertices V1 and V2 (Fig. 6) or the vertices V2 and V4 (Fig. 8) (i.e., the position where the roller electrodes 16R and 16L climb onto it) based on the vertical position (Z-coordinate) and horizontal position (X-coordinate or Y-coordinate) of the roller electrodes 16R and 16L. 7, the position where the roller electrode 16R falls from the workpiece W (i.e., vertex V3) is the position at the timing immediately before the roller electrode 16R starts to move downward, so this position may be the position of vertex V3. In this way, based on the vertical positions (Z coordinate) and horizontal positions (X coordinate or Y coordinate) of the roller electrodes 16R and 16L, the controller 25 may determine the horizontal positions (X coordinate or Y coordinate) at the timing immediately before the roller electrodes 16R and 16L start to move downward (particularly when they continue to rise for a predetermined distance or more) (FIG. 7) to the positions of vertices V3 and V4 (FIG. 6) or vertices V1 and V3 (FIG. 8) (i.e., the positions immediately before the roller electrodes 16R and 16L fall).

[0079] Furthermore, when the vertical positions detected by the position detection sensors 24R and 24L (or 124R and 124L) in sequence during seam welding are outside a predetermined range, the controller 25 performs a predetermined process as a process for when an abnormality occurs in the seam welding, thereby enabling appropriate processing for the abnormality in the seam welding and enabling better seam welding. As the predetermined process, the controller 25 may stop the seam welding. The process as described above is particularly effective when the workpieces W are sequentially held on the carrier board 90 and seam welding is performed sequentially. This is because in such a case, the position of the workpiece W relative to the carrier board 90 may be shifted.

[0080] The above embodiment may be modified in various ways. For example, each member and device of the above embodiment may be appropriately changed to other members having similar functions. For example, the linear motors 13R and 13L may be changed to a combination of a motor and a ball screw. The position detection sensor 21 may be configured with an appropriate sensor such as an optical distance meter. There may be only one roller electrode. The carrier board 90 may hold a plurality of workpieces W. In this case, the positions of the vertices V1 to V4 of each workpiece W may be specified and registered. After the X coordinates of the vertices V1 to V4 are registered in the state of FIG. 6, seam welding may be performed without rotating the stage 11, and then the Y coordinates of the vertices V1 to V4 of the stage 11 may be registered and seam welding may be performed. In addition, when registering the coordinates of the vertices V1 to V4, the Z coordinate may be omitted. On the other hand, the controller 25 may determine the positions of the moving members 14R and 14L during seam welding based on the Z coordinate. The seam welding apparatus 10 may be configured such that the stage 11 is fixed and the roller electrodes 16R and 16L, etc. are moved relative to the stage 11 by moving them.

[0081] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above-mentioned embodiments. For example, the present invention includes various modifications to the above-mentioned embodiments that can be understood by a person skilled in the art within the scope of the technical concept of the present invention. The configurations listed in the above-mentioned embodiments can be appropriately combined within a range without contradiction. [Explanation of symbols]

[0082] 10...seam welding apparatus, 11...stage, 12...first drive mechanism, 13...second drive mechanism, 14R, 14L...support member, 15R, 15L...holding member, 16R, 16L...roller electrode, 16RA, 16LA...working end, 21...position detection sensor, 22...position detection sensor, 23R, 23L...position detection sensor, 24R, 24L...position detection sensor, 25...controller, 27...input / output device, W...workpiece, W1...package, W2...lid.

Claims

1. a roller electrode that rolls on one side of an upper surface of a workpiece to perform seam welding on the workpiece; a drive mechanism that moves the roller electrode in a vertically movable state in a horizontal direction along the one side relative to the workpiece within a movement range that includes a rolling section in which the roller electrode rolls on at least a portion of the one side; a vertical position detection sensor that detects a vertical position of the roller electrode when the roller electrode is moved within the movement range by the drive mechanism; a controller configured to control the drive mechanism and the application of a voltage to the roller electrode for the seam welding; a horizontal position detection sensor that detects a horizontal position of the roller electrode relative to the workpiece in the horizontal direction, the movement range includes a section in which the roller electrode rides on the one side, The controller: based on the vertical positions detected sequentially by the vertical position detection sensor and the horizontal positions detected sequentially by the horizontal position detection sensor during a period in which the roller electrode moves relatively within the movement range before the seam welding, the horizontal position detected at a timing when the upward movement of the vertical position ends is specified; controlling the drive mechanism and the voltage application to the roller electrode, and causing the roller electrode to perform the seam welding by starting the voltage application to the roller electrode from a start position corresponding to the identified horizontal position; Seam welding equipment.

2. A roller electrode that rolls on one side of an upper surface of a workpiece to perform seam welding on the workpiece; a drive mechanism that moves the roller electrode in a vertically movable state in a horizontal direction along the one side relative to the workpiece within a movement range that includes a rolling section in which the roller electrode rolls on at least a portion of the one side; a vertical position detection sensor that detects a vertical position of the roller electrode when the roller electrode is moved within the movement range by the drive mechanism; a controller configured to control the drive mechanism and the application of a voltage to the roller electrode for the seam welding; a horizontal position detection sensor that detects a horizontal position of the roller electrode relative to the workpiece in the horizontal direction, the moving range includes a section in which the roller electrode falls off the one side, The controller: based on the vertical positions detected sequentially by the vertical position detection sensor and the horizontal positions detected sequentially by the horizontal position detection sensor during a period in which the roller electrode moves relatively within the movement range before the seam welding, the horizontal position detected at a timing immediately before the vertical position starts to move downward; controlling the drive mechanism and the voltage application to the roller electrode, and causing the roller electrode to perform the seam welding by applying the voltage to the roller electrode up to an end position corresponding to the specified horizontal position; Seam welding equipment.

3. the vertical position detected by the vertical position detection sensor is indicated by a moving distance of the roller electrode in the vertical direction; 3. The seam welding apparatus according to claim 1 or 2.

4. a holding member that rotatably holds the roller electrode and is movable up and down together with the roller electrode; A support member that supports the holding member so as to be movable in the up and down direction, the drive mechanism moves the roller electrode relative to the workpiece while the holding member is movable up and down relative to the support member; the vertical position detection sensor detects the relative position of the holding member with respect to the support member as the vertical position of the roller electrode; The seam welding apparatus according to any one of claims 1 to 3.

5. The controller performs a predetermined process as a process to be performed when an abnormality occurs in the seam welding when the up-down positions detected sequentially by the up-down position detection sensor fall outside a predetermined range during a period in which the controller controls the drive mechanism and the roller electrode to cause the roller electrode to perform the seam welding. The seam welding apparatus according to any one of claims 1 to 4.

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