JP2003001432A - Voltage boosting type welding method and equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding method for performing stable welding irrespective of the size of an article, and a welding equipment capable of effectively performing this welding method. SOLUTION: This welding method comprises an initial pressing step of pressing a member to be welded against a base welding material, energizing- pressurizing step of increasing the pressure F to be applied to a space between the member to be welded and the base welding material according to the rise of the welding voltage while increasing the effective value of the welding voltage V applied between the member to be welded and the welding base material as the elapse of time, and a terminating step of releasing the pressure F applied between the member to be welded and the welding base material when the predetermined time is elapsed after the energization of the welding voltage V is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage rising type welding method and welding apparatus, and more particularly to a welding method and a welding apparatus using this method, which can perform stable welding regardless of the size of an object.

[0002]

2. Description of the Related Art Conventionally, metal welding methods include fusion welding for melting and adhering a joint portion, pressure welding for pressing the joint portion in a heated and softened state, or a metal bonding agent melted at the joint portion. Brazing is known in which pressure is applied so as to sandwich. A wide variety of such welding methods have been put to practical use, but as fusion welding, TIG welding (Tungsten Inert-gas arc
welding), arc welding, stud welding, etc., and pressure welding includes resistance welding and ultrasonic welding.

For example, when welding a screw to a metal plate,
Stud welding is often used. Stud welding
An arc is generated while the gap between the member to be welded (metal stud) and the welding base metal is adjusted to melt the joint portion and pressurize the joint. When welding metal plates to each other, resistance welding is often used. A typical spot welding among resistance welding is a method of pressing and sandwiching stacked metal plates with opposed electrodes, and applying a large current to instantaneously melt and press the pressing points. Further, in the case where the lid is airtightly welded to the can body, beam welding is often used. That is, in a vacuum, a laser beam is irradiated along the entire boundary along the boundary between the can body and the lid to melt and weld the boundary.

[0004]

However, when a stud welding of a screw having a thickness of, for example, 1 mm to a plate-shaped welding base metal is attempted, a spark is generated between the screw and the base metal, and the screw is scattered. There was a dislike that it was difficult to determine the welding position due to transient melting. Further, in spot welding, the contact portion between the member to be welded and the welding base material is melted by Joule heat and pressure-welded by an energizing current, but a large pressure force is required, so welding of thin wires, etc. was difficult. Further, when trying to spot-weld dissimilar metal plates having different resistivities, a difference occurs in the molten state of the metal plates during energization, making it difficult to obtain stable bonding. Further, in the airtight welding using the beam welding, it is difficult to accurately irradiate the beam on the boundary portion between the can body and the lid described above, the airtightness cannot be obtained, and the defective rate is high. Further, since the beam welding apparatus is expensive and the cost of mass-produced products is increased, improvement has been desired.

The present invention is proposed in view of the above circumstances, and an object of the present invention is to propose a new welding method capable of performing stable welding regardless of the size of an object. Another object of the present invention, which is also proposed at the same time, is to provide a welding apparatus that effectively implements this welding method.

[0006]

DISCLOSURE OF THE INVENTION The present invention, which is proposed to achieve the above object, includes an initial pressurizing step of pressurizing a member to be welded and a welding base metal, and welding with a member to be welded over time. An energizing and pressurizing step for increasing the effective value of the welding voltage applied to the base metal and increasing the pressure applied between the member to be welded and the welding base metal in accordance with the increase in the welding voltage, and welding. And a termination step of releasing the pressure applied to the member to be welded and the welding base metal after a lapse of a predetermined time from the stoppage of energization of the voltage.

Here, it is necessary to increase the pressing force as the welding voltage applied between the member to be welded and the welding base metal is higher during welding. That is, as the welding voltage increases, an arc is likely to occur, and the spray transfer accompanying the arc increases the gap between the member to be welded and the welding base metal. Therefore, the melting range of the contact portion is unnecessarily widened and the finished state of welding is deteriorated. The present invention, by increasing the welding voltage while also increasing the welding pressure, the state immediately before the arc is generated, or while maintaining the arc length as small as possible,
It is a novel welding method characterized in that heat required for welding is efficiently accumulated by Joule heat generated in contact resistance due to energization of a contact portion.

According to the welding method of the present invention, the member to be welded is positioned with respect to the base material to be welded while an extremely low pressure is applied between the member to be welded and the base material to be welded in the initial pressing step. . Next, the energizing / pressurizing step is started to start welding. In the energizing / pressurizing step, welding is started in a state where a low voltage and a low pressure are applied between the member to be welded and the welding base material. Then, the welding voltage is increased with the passage of time, and the pressing force is also increased in accordance with the increase of the welding voltage. As a result, heat is accumulated by the Joule heat generated in the contact resistance due to energization of the contact portion while maintaining the state immediately before the arc generation or the state where the minute arc is generated in the contact portion. After that, when the necessary heat is accumulated in the contact portion and the optimum melting state is achieved, the pressing force reaches the optimum value (forging pressure). When this energizing / pressurizing step is completed, the ending step is started.
In the finishing step, the welding voltage is stopped while the forging pressure is still applied. Then, after a lapse of a predetermined time from the stoppage of energization of the welding voltage, the molten portion is cooled and fixed, and then the pressure is released to complete the welding.

As described above, according to the present invention, the heat required for welding can be efficiently accumulated and melted in the contact portion between the member to be welded and the welding base metal, and unnecessary power consumption is reduced. . In addition, welding is completed by applying an optimum forging pressure in an optimum molten state. As a result, it is possible to minimize defects such as swelling of the melted portion due to excessive melting or excessive pressurization, and spatter, and a good finish is obtained. In the present invention, the welding voltage may be either direct current or alternating current, and the effective value of the voltage applied between the member to be welded and the welding base metal may be increased with time.

In the present invention, the energizing / pressurizing step is performed while adjusting at least one of the welding voltage and the pressing force in accordance with the temperature or the arc generation state at the contact portion between the member to be welded and the welding base metal. You can When the member to be welded and the welding base material are predetermined, the rising curve of the welding voltage and the pressing force may be fixedly set in advance.
However, depending on the temperature (melting state) or the arc generation state at the contact area, by adjusting the welding voltage or pressure, or both, optimal welding can be performed according to the material to be welded and the welding base metal. It can be performed and the versatility is improved.

In the present invention, the energizing / pressurizing step can be carried out by applying a pulse voltage between the member to be welded and the welding base metal so as to increase the peak value with the passage of time.
In welding, if the materials to be welded and the welding base material are different, the resistivity is also different. For this reason, when electricity is applied, the amount of heat generated by a material having a high resistivity is large, and the amount of heat generated by a material having a low resistivity is small, so that a difference in molten state occurs and stable welding cannot be performed.

However, by applying the pulse voltage, heat can be applied to both the member to be welded and the welding base metal having different resistivities in a short time to raise the temperature.
By repeatedly energizing this pulse voltage while increasing the peak value, the contact portion can be effectively heated. In particular, by making the rise of the pulse voltage steep, the contact portion can be rapidly heated by the rise of the pulse, which is more suitable for welding materials having different resistivities.

That is, in the initial stage of the energizing and pressurizing step, the Joule heat and the heat from the arc are added to the contact portion to be melted while the arc is about to be generated or the arc length is kept as small as possible. . Then, in the latter half of the energizing / pressurizing step, in addition to heat input by the arc, Joule heat is further generated by the pulse voltage having a sharp rising edge. As a result, heat can be applied to the contact area in a short time to melt it, and the amount of heat generated due to the difference in the shape (cross-sectional area, etc.) of the member to be welded or the welding base metal or the difference in resistivity due to the material. It is possible to suppress the influence of the difference.

Further, by making the repetition frequency of the pulse voltage higher than the frequency of the commercial AC power source, the heat input can be accumulated in a short time, and the sustainability of the minute arc is also improved. Further, instead of applying a pulse voltage that raises the peak value, for example, it is possible to adopt a configuration in which the pulse value is constant and the pulse width is changed or the repetition period (frequency) of the pulse voltage is changed. is there.

The welding device of the present invention proposed at the same time has a power supply unit for generating a welding voltage for changing the effective value with time and applying it between the member to be welded and the welding base metal, and with the passage of time. Accordingly, the pressurizing means for changing the pressurizing force to apply between the member to be welded and the welding base material, and the control means for performing welding control including control of the power source part and the pressurizing means are provided. . According to this configuration, the control unit can control the power supply unit during the period from the start of energization to the end of energization, and can control the pressurizing unit during the period from the start of pressurization to the end of pressurization. It is possible to effectively carry out the welding method of the present invention.

In the present invention, the power supply unit may be configured to generate a pulse voltage that raises the peak value with the passage of time. With this configuration, it is possible to effectively carry out the welding method according to the third aspect.

In the present invention, the power supply unit supplies a transformer having a primary-side three-phase winding and a secondary-side single-phase winding, and a three-phase AC energization phase connected to the primary side of the transformer. A phase control means for controlling and a peak value control section for controlling the peak value of the pulse voltage output from the secondary side single phase winding of the transformer can be provided.

As the phase control means, for example, a structure in which a thyristor is used to change the ignition phase of the three-phase AC can be adopted. When the energization phase of the three-phase AC is controlled, energization is performed by the thyristor on the primary side of the transformer every half cycle of each phase from the predetermined ignition phase to the extinction phase (zero phase). As a result, a pulse voltage (pulse voltage of the same polarity) having a frequency three times that of a three-phase alternating current can be generated on the secondary side of the transformer. The crest value of this pulse voltage can be controlled by the crest value control unit to generate, for example, a pulse voltage whose crest value rises as a welding voltage.

In particular, by adopting a structure in which the impedance of the transformer (the inductance of the coils on the primary side and the secondary side) is reduced, the power factor is improved and the phase output from the secondary side of the transformer is improved. The rise of the controlled pulse voltage can be made extremely steep. Further, the peak value control unit can be configured by combining well-known circuits.

Further, it is also possible to adopt a configuration in which the phase control is performed only for a specific one phase of the three-phase alternating current applied to the primary side of the transformer and the other two phases are not energized. It is also possible to adopt a configuration in which phase control is performed for specific two phases and no other one phase is energized.

In the present invention, the pressurizing means may be provided with a biasing member, and the control means may control the biasing force of the biasing member. In the present invention, the pressing force applied to the member to be welded and the welding base material is increased according to the increase in the welding voltage. However, the member to be welded and the welding base material must be heated and melted in a short time, and the welding voltage and the pressing force must be increased in an extremely short time. Here, the welding voltage can be electrically controlled by the power supply unit as described above, but it is difficult to increase the pressing force in a short time.

In the present invention, the pressing means may be provided with a biasing member that sharply increases the pressing force using a spring.
It is also possible to equip the pressing means with a biasing member that generates an electromagnetic force by using a welding current. Then, the urging force of the spring or the electromagnetic force is adjusted by the control means to be used as the pressing force. For example, in the case where the compression opening mechanism is combined with a spring, the pressing force that sharply increases at the start of welding can be applied by opening the compressed spring by the control means. In addition to the urging member using a spring or an electromagnetic mechanism, for example, a urging member using an air cylinder may be used together to obtain the necessary pressurizing characteristics.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a voltage rising welding method according to the present invention will be described below with reference to the drawings. Figure 1
Is a graph showing the welding method of the present embodiment, where the horizontal axis is the time axis and the vertical axis is the welding voltage V, the applied pressure F, and the heat amounts E1 and E2, and the changes according to the progress of welding are shown. It is shown superimposed. Further, FIG. 2 is a diagram schematically showing the arrangement of the member to be welded, the welding base material, the welding electrode, and the pressing means during welding.

In the welding method of this embodiment, as shown in FIG. 2, a welding voltage is applied between the fixed electrode 31 and the pressure electrode 32. The fixed electrode 31 is fixed, and the pressurizing electrode 32 is provided with biasing members So to S2, so that the electrodes 31, 32
The welding base material W1 and the member to be welded W2, which are placed between the members, are configured to apply a pressing force. Here, the urging tool So generates a pressing force in the initial pressurizing step, and is configured by using a spring. Further, the urging tool S1 is for generating a pressing force that sharply increases in the initial stage of the energization and pressurization step, and is configured by using a spring. Further, the urging tool S2 uses an air cylinder and the energization and pressurization step. From this to the end step, a pressing force (forging pressure) is generated.

The welding method of this embodiment will be described in detail with reference to FIGS. 1 and 2. In the initial pressurizing step, the member W2 to be welded is brought into contact with the welding base metal W1, and the urging tool So is operated to bring the pressure electrode 32 into contact with the member W2 to be welded to apply a pressing force. As a result, the member W2 to be welded is pressed against the welding base material W1 by a slight pressing force and positioned. This initial pressurizing step is in a standby state before welding is started.

In the energizing / pressurizing step, energization of the pulsed welding voltage V is started and the biasing tool S1 is actuated to apply the pressing force. The welding voltage V is a pulse voltage with a pulse width t1 and is repeatedly applied at every period to, and the peak value increases with time. On the other hand, the pressurization by the urging tool S1 is applied almost at the same time when the welding voltage V is started, and the applied pressure sharply increases. Then, in the vicinity of the start of energization of the predetermined number of pulse voltages V (third pulse voltage in FIG. 1), the pressing force by the urging tool S1 becomes maximum. In the initial stage of this energization / pressurization process, the contact portion is heated by the sharp rise of the pulse voltage V, and the energization is repeated in a state where a minute arc is generated or immediately before the arc is generated. As a result, the heat quantity E1 due to the arc and the heat quantity E2 due to the Joule heat are accumulated in the contact portion.

In the energizing / pressurizing step, when the pressing force F of the biasing tool S1 reaches the maximum value, the pressing by the biasing tool S2 is subsequently started. As shown in FIG. 1, the pressure applied by the urging tool S2 gradually increases with time. In the latter half of the energizing / pressurizing step, the crest value of the pulse voltage further increases, and the amount of heat E2 due to Joule heat further increases due to the steeply rising pulse voltage, and heat input is effectively applied to the contact portion. Then, the application of the forging pressure is started immediately before the peak value of the pulse voltage V reaches the maximum value, and in the vicinity of the maximum peak value of the pulse voltage V, the pressing force F is saturated and a substantially constant forging pressure is applied. . At the end of this energizing and pressurizing step, the molten state of the contact portion is optimized, and forging pressure is applied to perform welding.

When the final step is entered, the energization of the pulse voltage V is stopped, the molten portion is pressed by forging pressure to be welded, and cooling is started. When the member W2 to be welded adheres to the welding base material W1 after a predetermined time has elapsed, the pressing force F is released and welding is completed.

As described above, according to the voltage rising welding method of the present embodiment, when the contact portion between the member to be welded W2 and the welding base metal W1 reaches the optimum melting state, the optimum forging pressure is applied to perform welding. Can be made. In other words, the idea is naturally different from spot welding in which a large voltage is applied and instant welding is performed according to set conditions before the start of welding, with a large pressure applied. By adopting the welding method of the present invention, the molten state can be spread and welded while the molten state and the pressing force are adjusted, and welding with a good finish can be realized. Moreover, since welding is performed while effectively applying heat input to the contact portion, unnecessary power consumption can be reduced. According to this voltage rising type welding method, by performing a welding test in advance on various materials to obtain the optimum values of the welding voltage V and the pressing force F, it is possible to obtain extremely good welds of different materials. Welding can be done. In addition, it is possible to perform stable welding by adjusting and setting the welding voltage V and the pressing force F from a small object to a large-sized welded object.

[0030]

EXAMPLES Next, examples of the welding apparatus of the present invention for effectively implementing the above-mentioned welding method will be described. FIG. 3 is a configuration diagram of the welding apparatus 1 of the present invention, and FIG. 4 shows waveforms of respective parts of the welding apparatus 1. The welding device 1 has a control means 1
0, a power supply unit 20, and a pressurizing unit 30. The pressurizing means 30 is the same as that shown in FIG. 2, and the same reference numerals are given to omit duplicated description. The control means 10 centrally controls the constituent elements of the welding device 1 including the power source section 20 and the pressurizing means 30 according to each control process. That is, the control means 10 sends a control signal to the power source section 20 to control the welding voltage and sends a control signal to the pressurizing means 30 according to the initial pressurizing step, the energizing pressurizing step and the final step. Control the applied pressure.

The power supply unit 20 includes a phase control unit 21 and a transformer 2.
5 and the peak value control unit 26, the welding voltage output from the power supply unit 20 is the electrodes 31, 32 of the pressurizing means 30.
To be welded. Here, the phase control unit 21 and the transformer 25 forming the power supply unit 20 are described in Japanese Patent No. 28.
It has the same configuration as the power supply device already registered in No. 84547.

The phase controller 21 includes a zero-cross detector 22 for detecting the zero-cross of each phase of the three-phase AC, thyristors 24a to 24c connected in series for each phase, and a phase for controlling the firing phase of the thyristor. The adjusters 23a-23c are provided. This phase control unit 21 uses the zero-cross detector 2
The zero phase is detected by 2 and transmitted to each of the phase adjusters 23a to 23c, and each of the phase adjusters 23a to 23c sends an ignition signal toward the thyristors 24a to 24c at a phase delayed by a predetermined phase from the zero phase. . As a result, as shown in FIG. 4A, the primary coils 25a to 25c of the transformer 25 are provided.
For each phase, energization is performed only from the ignition phase of the thyristors 24a to 24c to the extinction phase (zero phase).

When the phase controller 21 energizes the primary coils 25a to 25c of the transformer 25 as shown in FIG. 4A, the pulse voltage shown in FIG. 4B is induced in the secondary coil 25d. To be done. The frequency of this pulse voltage is three times the frequency of the three-phase alternating current. Then, the generated pulse voltage is converted by the crest value control unit 26 into a pulse voltage whose crest value and pulse width increase. That is, the peak value control unit 2
In FIG. 6, as shown in FIG. 4 (c), the pulse voltage is converted into a pulse voltage in which the peak value V increases with the passage of time and the pulse width t1 also increases, and this pulse voltage is used as a welding voltage via the terminals a and b. And is applied to the electrodes 31 and 32.

Here, the welding apparatus 1 of this embodiment is designed so that the impedance of the transformer 25 is extremely low. That is, the primary side coils 25a to 2 of the transformer 25
5c and the secondary coil 25d have extremely low inductance. As a result, FIG.
As shown in (b), the rise of the pulse voltage can be made steep, which enables welding in dissimilar metals.

Further, the power supply section 20 outputs a pulse voltage having a frequency three times the frequency of the three-phase AC voltage.
As a result, it is possible to effectively accumulate heat input between the member W2 to be welded and the welding base metal W1 in a short time, and to stably maintain the minute arc. In this way, the welding apparatus 1 of this embodiment can effectively carry out the above-described welding method of the present invention.

(Welding Example 1) FIG. 5 shows a welding example by the welding device 1 of the present embodiment, in which a lithium ion battery used for a mobile phone or the like is hermetically welded. As shown in FIG. 5A, the split electrodes 32a, 32a and the split electrode 32b are formed on the outer peripheral surface near the opening of the can body (battery body case) W1 placed on a pedestal (not shown) from the front, back, left and right.
32b is abutted and pinched. Next, the lid W1 is placed in the opening, and the electrode 31 is brought into contact with the lid W1. Split electrode 32
The a and 32a and the split electrodes 32b and 32b are all connected to the a terminal of the welding voltage (peak value controller 26), and the electrode 31 is connected to the b terminal of the welding voltage. Then, a welding voltage is applied between the split electrode 32 and the electrode 31. Further, the pressing force F is applied by pressing the electrode 31 downward by the pressing means 30.

The welding procedure in this case is omitted because it is the same as that described in the above embodiment, but by using the welding apparatus 1 of the present invention, the lid W2 is hermetically welded to the can body W1 in an extremely short time. Therefore, a good finish can be obtained without the occurrence of burrs in the welded portion. In particular, in such welding, the lid W2 and the can body W1 made of different materials are often welded. In other words, in the initial stage of the energizing and pressurizing step, a difference in heat generation may occur between the two materials due to a difference in resistivity at the boundary between the lid W2 and the can body W1. In this case, in the initial stage of the energizing and pressurizing step, the material having the low resistivity does not melt, but the energizing current concentrates on the material having the high resistivity or the portion having the small cross-sectional area, and the melting precedes. Therefore, when the pressure is low, the melting of a part of the contact surface may be delayed. However, as the welding voltage and pressure increase, sufficient heat input is also applied to the part where the melting is delayed due to the steep rising pulse voltage, and there is a slight difference in the melting state, but both materials are sufficiently melted. It becomes possible to weld.

(Welding Example 2) FIG. 6 shows another welding example in which large-diameter pipes are welded to each other. still,
The same components as those of the welding example 1 are designated by the same reference numerals, and duplicated description will be omitted. In this example, steel materials having an outer diameter of 500 mm and a thickness of 10 mm between the welding base material W1 and the member W2 to be welded are butted against each other and welded. Conventionally, it was difficult to weld the end face of such a large member, but with the welding apparatus 1 of the present invention, in a short time of about 3 seconds to 4 seconds,
Welding is possible and the finish is good. In this example, even when the contact between the abutting portions of the welding base material W1 and the member W2 to be welded is not good, the welding voltage (pulse voltage) is increased and the pressing force F is increased while melting the contact portions. To go. As a result, melting progresses along the circumferential direction of the abutting portion, and by finally applying the forging pressure, it is possible to secure good welding.

(Welding Example 3) FIG. 7 shows another welding example, in which another pipe is welded at a right angle to a large diameter pipe. The same components as those of the welding examples 1 and 2 are designated by the same reference numerals, and duplicate description will be omitted. In this example, as shown in FIG. 7B, the lower edge W of the welded member W2 is
There may be a state where the 2a and the welding base material W1 are only partially in contact with each other. However, as the welding voltage (pulse voltage) is increased and the contact portion is melted and the pressing force F is increased, the melting spreads in the circumferential direction at the end of the welded member W2 as the melting progresses. Then, by finally applying the forging pressure, it is possible to secure good welding.

(Welding Example 4) FIG. 8 shows still another welding example, in which a frame frame or the like is welded.
The same components as those of the welding examples 1 to 3 are designated by the same reference numerals, and duplicate description will be omitted. In this example, an end portion of an angle having a groove-shaped cross section is inclined and cut at 45 °, and the cut surfaces are abutted to each other so that the angles are orthogonal to each other and welded. Also in this example, as shown in FIG. 8B, there may be a case where the abutting portion of the member W2 to be welded and the welding base metal W1 are not in partial contact with each other.
However, the pressing force F is generated while melting the contact part with the pulse voltage.
It is possible to ensure good welding by increasing the welding temperature, causing the melting to proceed along the abutting portion of the angle, and finally applying the forging pressure.

As described above, according to the welding apparatus 1 of the present invention, it is possible to easily and quickly perform welding that cannot be performed by the conventional spot welding. In particular, since the applied pressure is increased while the heat input is effectively applied to the welded portion while the welding voltage is increased, wasteful power is not required and the finish of welding is good. Furthermore, since no special member is used in the welding apparatus 1 itself, the welding apparatus 1 can be manufactured at low cost and the welding cost can be reduced.

In the welding apparatus 1 shown in the above embodiment,
Although the pulse voltage is used as the welding voltage, the present invention is not limited to such a configuration. For example, a DC voltage whose voltage value increases with time may be used as the welding voltage, or an AC voltage whose effective value increases with time may be used. Further, it is also possible to adopt a configuration in which the temperature of the contact portion between the member to be welded W2 and the welding base metal W1 and the arc generation state are detected by a non-contact sensor or the like, and the welding voltage value and the pressing force are feedback-controlled. With this configuration, the optimum pressure can be applied in the optimum molten state, and a better finish can be obtained even when welding dissimilar metals or the like.

[0043]

According to the voltage rising welding method of the present invention as set forth in claim 1, the welding portion is effectively melted in a short time regardless of a minute object or a large-sized object to be in an optimum state. It is possible to pressurize and obtain a good finish. In particular, even in the case where the welding shape is long and TIG welding, beam welding and the like have been conventionally adopted, it is possible to perform efficient welding in a short time and obtain a good finish. In addition, it is possible to reduce wasteful power consumption. According to the present invention described in claim 2, it is possible to perform welding while monitoring the temperature of the welded portion and the occurrence of arc, and it is possible to further improve versatility. According to the present invention as set forth in claim 3, it becomes possible to effectively heat and melt the welded portion by using the pulse voltage whose peak value increases. According to the present invention described in claims 4 to 7, it is possible to effectively carry out the welding method of the present invention described in claims 1 to 3, and to provide an inexpensive welding apparatus.

[Brief description of drawings]

FIG. 1 is a graph showing the progress of welding in the welding method of the present invention for each step with the horizontal axis representing time and the vertical axis representing welding voltage, applied pressure, and heat generation amount.

FIG. 2 is a schematic diagram showing a method of applying a pressing force adopted in the welding method shown in FIG.

FIG. 3 is a configuration diagram of a welding device of the present invention.

4A to 4C are voltage waveforms at various parts of the welding apparatus shown in FIG.

5A is a perspective view showing a welding example using the welding device shown in FIG. 3, and FIG. 5B is a perspective view showing a finish after welding is completed.

6A and 6B are perspective views showing another welding example using the welding apparatus shown in FIG. 3, and FIG. 6C is a perspective view showing a finish after welding is completed.

7A is a perspective view showing another welding example using the welding apparatus shown in FIG. 3, and FIG. 7B is an explanatory view showing the spread of melting.

8A and 8B are perspective views showing another welding example using the welding device shown in FIG. 3, and FIG. 8C is a perspective view showing a finish after welding is completed.

[Explanation of symbols]

1 welding equipment 10 Control means 20 power supply 21 Phase control means 25 transformer 25a, 25b, 25c Primary side three-phase winding 25d Secondary side single phase winding 26 Crest value control unit 30 Pressurizing means Vo welding voltage W1 welding base material W2 Welded member F Applied pressure So, S1, S2 biasing member

Claims (7)

[Claims] 1. An initial pressurizing step of pressurizing a member to be welded and a welding base metal, and increasing an effective value of a welding voltage applied between the member to be welded and the welding base metal over time, The current-pressurizing step of increasing the pressure applied between the member to be welded and the welding base metal in accordance with the rise of the welding voltage, and the member to be welded and the welding base metal after a lapse of a predetermined time from stopping the energization of the welding voltage. And a termination step of releasing the applied pressure. 2. The energizing and pressurizing step is performed while adjusting at least one of a welding voltage and a pressing force according to a temperature or an arc generation state at a contact portion between a member to be welded and a welding base metal. The voltage rising welding method according to claim 1, wherein the welding method is a voltage rising welding method. 3. The energizing and pressurizing step is performed by applying a pulse voltage between the member to be welded and the welding base metal, the pulse voltage increasing the crest value with the lapse of time.
Alternatively, the voltage rising type welding method according to item 2. 4. A power supply unit for generating a welding voltage for changing an effective value with time and applying it between a member to be welded and a welding base metal, and a welding force by changing a pressing force with time. A welding apparatus comprising: a pressurizing means applied between a welding member and a welding base material; and a control means for performing welding control including control of the power source section and the pressurizing means. 5. The welding device according to claim 4, wherein the power supply unit generates a pulse voltage that increases a peak value with the passage of time. 6. The power supply unit controls a transformer having a primary-side three-phase winding and a secondary-side single-phase winding, and a conduction phase of a three-phase alternating current connected to the primary side of the transformer. The welding apparatus according to claim 4, further comprising a phase control unit and a peak value control unit that controls a peak value of a pulse voltage output from the secondary side single-phase winding of the transformer. . 7. The pressing means comprises a biasing member,
7. The welding apparatus according to claim 4, wherein the control unit controls the biasing force of the biasing member.