JPH0790385B2 - Method for controlling work melting amount of butt welder and butt welder - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a method for controlling the amount of melted work in a butt welder, and a butt welder for implementing this control method.

[Prior art]

A welding method using a conventional butt welder will be described below with reference to FIGS. 5 to 9 showing an outline of a welding process and FIG. 12 showing a time chart thereof. Fig. 5 shows the set state of the welding work, 1,2,3,4 are
The upper left part electrode, the lower left part electrode, the upper right part electrode, and the lower right part electrode are respectively shown, and 5 and 6 show the welding work. As shown in the figure, in this state, work pieces are attached to the left and right lower electrodes 2 and 4.
5 and 6 are placed. It should be noted that the workpieces 5 and 6 to be joined are not always placed in a state in which both joint end surfaces 5a and 6a thereof are in close contact with each other, as shown in the figure. Fig. 6 shows the left and right upper electrodes 1,3
Shows the work clamp state in which the works 5 and 6 are pressed against the lower electrodes 2 and 4 with the pressing force Q. 7 and 8 in the figure are
Each of the left and right electrodes is shown as a set in which the upper and lower parts are combined. FIG. 7 and FIG. 8 respectively show a state in which the joining end surfaces 5a, 6a are pressed by the pressing force P and an energized state to the works 5, 6, respectively. It will be described with reference to FIG. First, as shown in FIG. 7, the right electrode 8 as a movable electrode.
Is urged in the direction of the left electrode 7 as a fixed electrode, the joining end surfaces 5a, 6a of the works 5, 6 move from a predetermined time t ₁ to t after t ₀ when the start switch of the welding machine is turned on. Up to ₆ , the pressure P is increased to a preset value P ₀ . Then, at the time after t ₁ when the predetermined pressing force P ₀ is reached, the left and right electrodes 7, 8 are operated during T ₂ from t ₂ to t ₄ after T ₁ as the initial pressurizing time t _0. As a result, a predetermined current I ₀ is applied as a welding current I to the works 5 and 6. Meanwhile, the joining end faces 5a, 6a of the butted work 5 and 6 at the same time from a certain time point t ₃ begins to soften and melted by the Joule heat, the amount of melt in the pressure P ₀ acts L increases at a rapid rate, At time t ₄ when the energization ends, the melting amount L is l ₁
Becomes Note that the joint end surfaces 5a and 6a start to soften / melt t ₃
The time point of changes a little due to variations in the works 5 and 6 themselves and changes in welding conditions. Needless to say, the time of t ₃ is not intended to be pre-set prior to welding. On the other hand, there is no increase in heat generation after t ₄ when the energization ends, but the applied pressure P ₀ is also applied during the holding pressurization time T ₃ from t ₄ to t ₆ until the time t _{5 at} which cooling proceeds to some extent. The melt amount l ₀ at t ₄ increases slightly, after which the weld 9 reaches the desired melt amount l. After that, the melted amount 1 does not increase, cooling progresses, and the welded portion 9 solidifies. Figure 9 shows the pressure release and unclamped states after t _6, the upper electrode 1 and 3 is that the pressing force P of the right electrode 8 is released, as shown lifted upward, joining The processed works 5 and 6 are taken out. The melting amount l of the works 5 and 6 described above is the joint end surface of the works 5 and 6.
As shown in FIG. 10 showing a state in which 5a and 6a are simply butted to each other and FIG. 11 showing a state of the works 5 and 6 after welding, an arbitrary 2 on the works 5 and 6 changing before and after welding. It is represented by the difference in distance between points a and b, that is, the difference between L ₀ and L ₁ . This melting amount l is also referred to as a melting margin or a deviation margin. Most of the joined end surfaces 5a, 6a of the melted works 5, 6 become welding burrs,
Part of it becomes spatter and scatters or adheres to the works 5 and 6.

[Problems to be Solved by the Invention]

In the above-described conventional welding method, welding current I ₀ , welding time such as energizing time indicated by T ₂ , welding pressure P _{0, and the} like are of course varied, and welding is performed by setting these welding conditions constant. In this case, due to variations in the shapes and properties of the joint end surfaces 5a and 6a of the works 5 and 6 and the wall thickness, as shown in FIG. There are many cases where the values change greatly as shown by l ₁ and l ₂ . Therefore, the strength and appearance of the welded portion 9 become unstable, and it is necessary to inspect the welded portion in order to know the quality of the welded portion. Therefore, the technical problem to be solved by the present invention is to stabilize the welding quality by controlling the welding machine so that the melting amount of the work when welding with the butt welding machine is always constant.

[Means for Solving the Problems]

In order to achieve the above technical problem, according to the present invention, the melting amount of the welding work is continuously measured from the moving amount of the movable electrode with respect to the fixed electrode, and the measured value ends energization for the desired melting amount. Provided is a work melt control method for a butt welding machine, characterized in that the energization is stopped at a time point to a preset reference value in consideration of an increase in the melt quantity within the holding pressure time afterwards. It Further, according to the present invention, with respect to the desired melt amount in the work, and the melt amount measuring means for continuously measuring the melt amount of the work from the moving amount of the movable electrode during welding and outputting the measurement value signal. A predetermined reference value is set in consideration of the increase in the amount of melt within the holding and pressurizing time after completion of energization, and the reference value and the measured value signal from the melt amount measuring means are continuously compared. And a melting amount setting means for outputting an energization stop signal when the measured value reaches the reference value, and an energization control means for stopping energization based on the energization stop signal from the melting amount setting means. A butt welder is provided. In the butt welder of this configuration, further, the melt amount display means for continuously displaying the melt amount during welding by the measurement value signal output from the melt amount measuring means, and the time point at which energization to the work is started and It is preferable to provide a reset means for outputting a reset signal of the displayed value at the start of welding including before and after the welding.

[Action / effect]

In the above configuration, the amount of melt of the welding work in the solution is first measured by the amount of melt measuring means based on the amount of movement of the movable electrode. While the measured value continuously changes during welding, the measured value is input to the melt amount setting means as a signal.
The melt amount setting means continuously compares the measured value with a preset reference value, and outputs an energization stop signal when the measured value reaches the reference value. The energization stop signal is input to the energization control means, and the energization control means stops energization of the work based on the signal. During the holding and pressurizing time, the melt amount of the work increases even after the energization is stopped.However, since the reference value is set in consideration of this increase amount, it is possible to always keep the final work melt amount constant. it can. Further, when the melted amount display means and the display value resetting means are provided, the melted amount is continuously displayed by the measured value signal. The displayed melt amount is reset to zero when welding is started, so it should be retained until the displayed value is reset at the end of welding (when the work clamp is released or pressure is released). By doing so, the final melted amount on the end face of the workpiece can always be known accurately. Therefore, according to this configuration, since the melting amount does not become excessive or insufficient, the welding quality is stable, the inspection of the welded portion can be simplified or omitted, and the generation of defective products can be prevented.

【Example】

The first to third embodiments of the present invention will be described below.
A detailed description will be given with reference to FIGS. 1 to 4. First, the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing a schematic configuration of a butt welding machine according to the first embodiment of the present invention, and FIG. 2 is a flowchart thereof. As shown in the figure, the left and right electrodes that hold the workpieces 5 and 6
7 and 8 are the upper left electrode 1, the lower left electrode 2,
It is composed of a right upper electrode 3 and a right lower electrode 4. A clamp device 16 such as a hydraulic cylinder is connected to each of the upper electrodes 1 and 3 to fix and release the works 5 and 6, and the right electrode 8 as a movable electrode has a joining end surface 5a of the works 5 and 6, 6a
In order to pressurize, the pressurizing device 20 including an air cylinder or the like is connected. The clamp device 16 and the pressurizing device 20 are respectively connected to the overall control device 11 that starts the operation of the start switch 10. The left and right electrodes 7, 8 are connected to the power source 1 via the transformer 15 and the initiator 14.
This starter 14 is connected to the
The energization control device 12 connected to 1 is connected. The open / closed state is controlled by the energization control device 12 based on a signal from the overall control device 11. The operations of the clamp device 16 and the pressurizing device 20 described above and the timing of energization are controlled by timers provided in the overall control device 11 and the energization control device 12. Further, the welding electrode is preset by the energization control device 12 before welding. The right electrode 8 has an arm 21 for actuating the melting amount measuring device 19.
Is provided, and the melt amount measuring instrument 19 measures the melt amount of the workpieces 5 and 6 based on the distance moved along with the pressurization of the joint end surfaces 5a and 6a of the arms 5 and 6 of the arm 21. The melt amount measuring device 19 is connected to a melt amount display device 18 which digitally displays the measured value as a signal A by connection. Further, the melt amount display device 18 is connected to a melt amount setting device 17 which receives the displayed value as a signal B and processes it. The melting amount setting device 17 has a reference value ((l in FIG. 12)) which is determined by subtracting the increase in the melting amount generated within the holding pressurization time after the end of energization from the desired melting amount (1 in FIG. 12). the 12 l ₀ in the figure) is set in advance, when the display value inputted as the signal B becomes equal to the reference value, the signal C is sent to the electrification control apparatus 12, the energization is stopped. Therefore, the welding work points 5 and 6 have different energization stop time points t ₄ and energization times T ₂ shown in FIG. That is, in the past, the value that the final melt was small
T ₂ are longer for work 5,6 such that l _1, conversely, T ₂ is shorter with respect to the workpiece 5 and 6 such that a large value l _2. The melting amount display device 18, which is also connected to the overall control device 11 and the energization control device 12, will be described in detail later, but the signals D and E from these reset the display value to zero and the display value. Retention is controlled. Next, the operating state of the butt welding machine having the above configuration will be described in detail with reference to the flowchart of FIG. First, by setting the works 5 and 6 and turning on the start switch 10 to start the operation (step 01), a drive signal is input from the overall control device 11 to the clamp device 16, and the clamp device 16 is activated. (Step 02), the works 5 and 6 are held by the electrodes 7 and 8. Next, in step 03, a signal is output from the overall control device 11 to the pressurizing device 20, the right electrode 8 is urged toward the left electrode 7 side, and the welding end surfaces 5a, 5a,
6a is pressurized. Then, in step 04, the energization control device 12 closes the switch 14 by a signal from the overall control device 11, and the energization of the works 5 and 6 is started. Further, in synchronization with this, in step 05, the display value reset signal D (FIG. 1) output from the energization control device 12 is input to the melting amount display device 18, and the display value is reset to zero. Next, in step 06, when the melting amount starts to increase with the energization of the works 5 and 6, the moving amount of the right electrode 8 is measured by the melting amount measuring device 19, and the value is displayed on the melting amount display device 18. . The displayed value is further sent to the melting amount setting device 17, but when the value reaches a preset reference value (step 0
In 7), the signal C is sent from the melting amount setting device 17 to the energization control device 12.
(Fig. 1) is sent, and the energization stops immediately (step
08). At this point, since the welded portion 9 is still in a high temperature and softened state, the melt amount slightly increases due to the pressurization of the right electrode 8, but the reference value set in the melt amount setting device 17 allows for this increase amount. Since the welded portion 9 is completely solidified, the melting amount is always a constant value. After that, the unclamping of the switch 09 and the release of the pressure in step 10 are started by the overall control device 11 at substantially the same time.At this time, the overall control device 11 synchronizes with either the unclamping or the release of the pressure. Then, a signal E for holding the display value of the melted amount is input to and output from the melted amount display device 18,
As a result, the display value is held (step 11). Immediately after this, the clamp cylinder moves up in step 12, and at the same time, the pressurizing cylinder retreats in step 13, whereby the operation ends in step 14. When the pressurizing cylinder retreats, the measurement value signal A from the melt amount measuring device 19 due to the movement of the arm 21 is input to the melt amount display device 18, but as described above, the display value is already displayed in step 1. Since it is held, the displayed value does not change. Therefore, the accurate value of the melted amount is displayed until after the end of the operation. Note that the display value is maintained until the next welding is started, and when the operation of the next welding is started, the display value is released from the retention of the display value by the signal from the overall control device 11. It can be reset. Therefore, even if the welding is repeated, the amount of melt is always measured and displayed accurately, and the final amount of melt is controlled to be always constant. As described above, according to the above configuration, even if the welding conditions such as the electric current and the pressing force and the work are not strictly controlled, the amount of melting can be always kept constant by giving flexibility to the energization time. As a result, the welding quality such as strength, appearance and size of the welded product is stable. Therefore, the inspection of the product can be simplified or omitted. Further, the final melt amount can be accurately and easily known on the display device 18. Next, the second embodiment shown in FIG. 3 will be described. FIG. 3 is a block diagram showing a schematic configuration of a butt welder according to the second embodiment of the present invention. This embodiment differs from the first embodiment in the configuration for resetting the display value in the melt amount display device 18. That is, the energization control device
12 and the melting amount display device 18 are not connected, a toroidal coil 23 is provided in the power supply circuit, and the coil 23 and the melting amount display device 18 are connected via the current measuring / display device 22. In the case of this configuration, when the energization of the works 5 and 6 is started, a current measurement signal is sent from the coil 23 to the current measurement / display device 22 by this current, and the current measurement / display is started. The melting amount display device 18 operates in the same manner as the first embodiment, except that the melting amount display value is reset by sending a signal D for resetting the display value synchronized with the start of energization. Therefore, the welding quality is stable as in the first embodiment. Further, the third embodiment shown in FIG. 4 will be described.
FIG. 4 is a block diagram showing a schematic configuration of a butt welder according to the third embodiment of the present invention. Also in this embodiment, the melting amount display device 18 is not connected to the energization control device 12, but instead is connected to the overall control device 11.
Therefore, the signal D for resetting the display value is output from the overall control device 11, and therefore a timer is added in the device 11. The operation state in this configuration is as shown in broken line in FIG.
After 20 is activated, energization is started in step 04, and the display value of the melt amount is reset in step 05 by the signal D from the overall control device 11 output after the set time of the timer has elapsed. . Therefore, the reset timing can be arbitrarily set by the timer. However, in reality, in order to accurately measure and display the melt amount, the reset value of the display value on the melt amount display device 18 is set at the joining end surfaces 5a, 6a of the works 5, 6 by pressing the right electrode 8.
It is preferable to set the time from when the connection is made to when the melting amount starts to increase by energization. Also in the case of such a configuration, as in each of the above embodiments,
Since the amount of melt is constant, the welding quality is stable.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a butt welding machine according to the first embodiment of the present invention, FIG. 2 is a flow chart showing its operating state, and FIG. 3 is a schematic of a butt welding machine according to the second embodiment. Block diagram showing the configuration, FIG. 4 is a block diagram showing a schematic configuration of the butt welding machine according to the third embodiment, FIGS. 5 to 12 show a conventional example, of which FIG. 5 to FIG. FIG. 10 is an explanatory diagram showing an outline of the process, FIGS. 10 and 11 are explanatory diagrams of the melting amount of the work, and FIG. 12 is a time chart. 1 ... upper left electrode, 2 ... left lower electrode, 3 ... upper right electrode, 4 ... lower right electrode, 5 ... work, 6 ... joining end face, 7 ... left electrode, 8 ... right electrode , 9 ... Welded part,
10 ... Startup switch, 11 '... General control device, 12 ... Electrification control device (energization control means), 13 ... Power supply, 14 ... Switch, 15 ... Transformer, 16 ... Clamping device, 17 ... … Melt amount setting device (melt amount setting means), 18 …… Melt amount display device (melt amount display means), 19 …… Melt amount meter (melt amount measuring means), 20 …… Pressurizing device, 21 …… Arm, 22 ... Current measurement / display device, 23 ... Toroidal coil

Claims (3)

[Claims] 1. A moving electrode (8) holding another welding work (6) is pressed against a fixed electrode (7) holding one welding work (5), and at the same time, each electrode (7, 8) is pressed. From the moving amount of the movable electrode (8) with respect to the fixed electrode (7), a method for controlling the melting amount of the workpiece in a butt welding machine for welding by energizing the workpiece (5, 6) from , 6) is continuously measured, and the measured value is set to a preset reference value in consideration of the increase in the amount of melt within the holding pressurization time after energization for the desired amount of melt. A method for controlling the amount of work melted in a butt welding machine, characterized in that energization is stopped when the temperature is reached. 2. A moving electrode (8) holding another welding work (6) is pressed against a fixed electrode (7) holding one welding work (5), and at the same time, each electrode (7, 8). In the butt welding machine that welds each work (5, 6) by energizing each work (5, 6) from the The melt amount measuring means (19) that continuously measures the amount and outputs the measured value signal, and the melt amount within the holding pressurization time after the end of energization with respect to the desired melt amount in the work (5, 6). A predetermined reference value is set in consideration of the increase in the amount, and the reference value and the measured value signal from the melt amount measuring means (19) are continuously compared, and the measured value reaches the reference value. Melting amount setting means (17) for outputting an energization stop signal at the time of Butt welding machine, characterized in that it comprises a current supply control means (12) for stopping the energization on the basis of the energization stop signal from 17). 3. A melt amount display means (18) for continuously displaying the melt amount during welding by a measurement value signal output from the melt amount measuring means (19), and a reset signal for the display value at the start of welding. The butt welding machine according to claim 2, further comprising reset means (12, 22, 11) for outputting the.