JPS63309378A - Method and equipment for heating metal plate to be welded - Google Patents

Abstract

PURPOSE:To improve the welding quality and efficiency by arranging induction coils facing to a metal plate and heating the metal plate to weld a metal frame while moving the metal plate relatively. CONSTITUTION:The metal frame 2 is mounted on the upper part of the metal plate 1 having an opening part 11 such as a window, etc., and an electromagnetic induction device 3 is arranged to the lower part of the metal plate via wheels 32. A wheel 4 to move a structural body consisting of the metal plate 1 and the metal frame 2 in the longitudinal direction is provided and a wheel 4' to prevent the structural body from deviating in the orthogonal direction is arranged. The electromagnetic induction device 3 is provided with the plural induction coils 31 and the respective coils are electrified to heat the metal plate 1. The size, a current value, frequency, a heating temperature, etc., of the coils 31 are selected to optimum conditions and the structural body is welded while being moved relatively by the induction electromagnetic force. Since the heating and movement of the object to be welded are carried out via the electromagnetic induction, the heating and welding are uniformalized and the welding quality and efficiency are improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a welding device that prevents distortion from occurring in a metal plate after welding when a structure is constructed by attaching a metal plate to a metal frame by welding. It is related to.

[Conventional technology]

When assembling metal plates by spot or arc welding on a metal frame, in order to prevent distortion of the plates after assembly, the metal plates are heated and attached to the frame immediately before welding, so that the metal plates are in a high temperature state. Sometimes, they were temporarily fixed to a frame by arc welding, and then the full-scale welding was performed (Patent No. 960051). Heating methods include electric heat in a furnace, flame of fuel, etc. (Japanese Patent Application Laid-open No. 6O-64791), infrared radiation (Japanese Patent Application No. 6O-269858), electrical current (Japanese Patent Application No. 6O-275298), etc. was there.

[Problem that the invention seeks to solve]

However, such conventional heating methods have the following problems.

First, in heating in a furnace (Japanese Patent Application Laid-Open No. 60-64791), the size of the metal plate is limited by the size of the furnace, and it is often not applicable to extremely large or long structures.

In heating by infrared radiation (Japanese Patent Application No. 60-269858), the heat is reflected on the surface of the metal plate, so the heat absorption efficiency is poor, it takes a long time to raise the temperature, and temperature unevenness tends to occur.

In electrical heating (Japanese Patent Application No. 6O-275298), when an opening exists in a metal plate, the current flow becomes uneven, the current concentrates at the corner of the opening, and the temperature rises locally. Uniform heating is not possible.

Furthermore, in the case of long structures, it is necessary to perform welding by heating in a longitudinal direction, but when welding is performed continuously, it is difficult to control the relationship between the feeding speed and the heating temperature.

The present invention was made in view of the problems of the prior art, and provides a heating method that does not cause distortion after welding when welding a metal plate to a metal framework, and that can be performed continuously and efficiently even for long structures. The purpose is to provide such equipment.

[Means for solving problems]

In order to achieve the above object, the present invention provides a method for welding and attaching a preheated metal plate to a metal frame, in which the metal plate is heated by an induction coil placed opposite to the metal plate, and This method is characterized by causing relative movement between the metal frames and welding the metal frame to the heated metal plate.

Further, the device for achieving the above object is characterized by being an electromagnetic induction device equipped with an induction coil that inductively heats a metal plate and causes relative movement between the metal plate and the metal plate.

[For production]

Next, the operation of the present invention will be explained. An electromagnetic induction device is equipped with an induction coil that forms a loop facing a metal plate, generates a magnetic field by passing an alternating current of a predetermined frequency through this coil, and then applies an induced current to the metal plate facing the magnetic field. induce. Because metal plates have inherent resistance,
This induced current generates heat. This calorific value (per unit volume) is expressed as follows.

Calorific value cc (frequency x specific resistance x current) / plate thickness The induction coil of an electromagnetic induction device can also generate a moving magnetic field by passing alternating currents with different phases, and the induced current in the metal plate facing this can be generated and the metal plate can be moved in response to the movement of the magnetic field. By combining the two functions of this electromagnetic induction device, the metal plates can be welded in a heated state, and the metal plates can be welded and attached to the metal frame while being sequentially moved.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows the entire apparatus of one embodiment of the present invention. 1 is a metal plate, 2 is a metal frame placed on it, and the assembled structure of 2 and 2 is, for example, a side structure of a vehicle body,
There is an opening 11 such as a window in a part of Ii1. 3 is an electromagnetic induction device installed across the bottom of the metal plate 1; 4 is a wheel that receives the structure from below and supports the structure to move in the longitudinal direction; 32 is the electromagnetic induction device 3; These are wheels or balls for maintaining a constant distance from the metal plate 1. 4′
are wheels that prevent the structure from shifting in a direction perpendicular to its longitudinal direction. 5 is a welding machine for joining and assembling the metal plate 1 and the metal frame 2, and 6 is a temperature sensor that detects the temperature of the metal plate and transmits the signal to a control device to be described later.

In FIGS. 2 and 3, 31 is an induction coil that forms a unit in the electromagnetic induction device, 311 is an iron core with grooves cut on the surface,
312 is a three-phase coil embedded in this groove. The induction coil produces a moving magnetic field in the direction of the arrow in FIG.

FIG. 4 shows the circuit of the electromagnetic induction device, where 7 is a power source, 8 is a control device that can change the frequency and voltage using a thyrisk inverter, etc., and each induction coil is supplied with power from this control device. A temperature detection signal from the temperature sensor 6 mentioned above is transmitted to this control device 8, and based on this signal, the control device 8 always supplies power to each induction coil 31 at the optimum frequency and voltage.

FIG. 5 is a plan view showing the configuration of the electromagnetic induction device 3, and FIG. 6 is a front view. Both induction coils generate heating and driving forces, and therefore these induction coils 3
The installation direction of metal plate 1 needs to be determined in consideration of the directionality of the force acting on metal plate 1.

That is, in order to prevent the metal plate from moving in an unexpected direction, each pair of induction coils 31 is provided with opposite phases so as to cancel out their driving forces. Then, a specific moving induction coil 31a is installed which generates a driving force in a required direction by the amount necessary for driving the metal plate 1.

The heating magnetic field combines a pair of magnetic fields as described above to cancel out the driving force in the longitudinal direction of the metal plate and in the direction perpendicular to it, but if the metal plate is asymmetrical due to a window, etc. The induction coil that comes to The feed rate of the metal plate 1 is controlled by changing the feed speed, and the driving force in the direction perpendicular to this is received by the wheels 4' to move the structure correctly in the longitudinal direction.

Next, the operation of the embodiment of the present invention will be explained. Electromagnetic induction coils 31 are arranged, and the electromagnetic induction generates an induced current in the metal plate 1 to generate heat. Further, a moving magnetic field is generated in the induction coil 31a, thereby moving the metal plate 1 and the metal frame 2 in the longitudinal direction.

The feed rate is adjusted by the excitation frequency of the moving magnetic field. While the metal plate l is heated to a desired temperature, it is fixed to the metal framework 2 by the welding device 5. Thereafter, when cooled over time, the metal plate 1 contracts and, after reaching room temperature, is assembled to the metal frame 2 with uniform tension and without distortion.

Coil size, current value 9 frequency, distance between coil and metal plate, feeding movement frequency, etc. are heating temperature.

Allowable temperature unevenness 9 Select depending on desired conditions such as assembly speed. Further, as described above, the heating temperature of the metal plate 1 can be detected by the temperature sensor 6 and fed back to the control device for optimal control.

The gap between the electromagnetic coil and the metal plate is the shape of the iron core of the induction coil,
It is determined by taking into consideration the efficiency and unevenness of the heating temperature of the metal plate, depending on the spacing between the iron cores and the strength of the magnetic field. The heating temperature unevenness is diffused by heat conduction during the time between heating the metal plate and welding it to the framework, and the temperature becomes uniform.

Note that the power supply method does not need to be from a single control device, and it is possible to combine a plurality of power sources and control devices according to the nine groups of uses of the induction coil.

Furthermore, instead of moving the metal plate and metal framework as in this embodiment, the plate and the framework may be fixed and the electromagnetic induction device and welding machine placed on a trolley and moved.

Figure 7 shows another embodiment in which a single iron core 31 is used, whereas the embodiment of Figure 5 has small units of induction coils installed in opposite directions.
1', a pair of coils 312 whose magnetic fields move in opposite directions;
In addition, the size of the induction coil may be an induction coil 31' that can cover the entire width of the metal plate 1 as shown in FIG. It is necessary to install a separate moving induction coil 31a.

FIG. 9 shows yet another embodiment in which a plurality of heating induction coils are arranged in a plurality of rows in the longitudinal direction of a metal plate, with the arrangement being slightly shifted in the width direction.

When arranged in this way, the metal plate and the coil correspond evenly, so the above-mentioned temperature unevenness can be reduced and the moving speed can be improved.

〔Effect of the invention〕

According to the present invention, a magnetic field is generated by an induction coil, thereby inducing an induced current in a metal plate, and the metal plate is heated by the induced current, and a moving magnetic field is generated to
Since relative movement is caused between the metal plate and the induction coil, and each can be easily controlled, the following effects are achieved.

■Using electromagnetic induction, heating is uniform and there is little loss, and there is no energy loss even if there are openings like windows.
Unlike the current method, the temperature at the corner of the opening does not rise too much.

,■.Since movement is performed while heating, it can be easily applied, especially to long structures, and is efficient.

(2) The amount of heat generated by electromagnetic induction is inversely proportional to the thickness of the plate, so if the plate is thin, it is effective because a high temperature can be obtained with a small amount of current.

(2) The assembly of metal plates and metal frames can be easily automated, resulting in high quality and high efficiency.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an apparatus for assembling a metal frame and metal plate using electromagnetic induction as an embodiment of the present invention, Fig. 2 is a perspective view of an induction coil used in the electromagnetic induction device, and Fig. 3 is an induction coil. Fig. 4 is a control circuit diagram of the electromagnetic induction device, Fig. 5 is a plan view with the cover omitted showing the configuration of the induction coil of the electromagnetic induction device, Fig. 6 is a front view of the same, and Fig. 7 is a diagram of the control circuit of the electromagnetic induction device. FIG. 8 is a plan view of the configuration of the induction coil in another embodiment. FIG. 9 is a plan view showing the arrangement of the induction coil in another embodiment. DESCRIPTION OF SYMBOLS 1... Metal plate, 2... Metal framework, 3... Electromagnetic induction device, 4.4'... Wheel, 5... Welding machine. Patent Applicant Kawasaki Heavy Industries, Ltd. Figure 4 Procedural Amendment (Voluntary) Commissioner of the Patent Office /J1 JIr $B Husband 1.
1. Beef Lx Patent Application No. 145229 filed in 1988 2. Name of the invention Method and device for heating metal plates to be welded 3. Relationship with the amended case Patent applicant address Higashi, Chuo-ku, Kobe City, Hyogo Prefecture Yozakicho 3-1-1 Name B
(097) JIT Saki Heavy Industries Co., Ltd. 4, Contents of amendment by agent (Patent Application 1982-145229) 1, Specification cylinder page 6, line 4, r312J to r312, 312', 312
2. Insert the following sentence between page 6 of the specification cylinder, line 6, “...generates a magnetic field.” and line 7, “Figure 4 is...” . "Fig. 3 (al) is a moving induction coil in which a pair of coils 312' and 312" whose moving directions are the same are provided on a single iron core 311, and Fig. 3 (b) 3
11, a pair of coils 312 whose magnetic fields move in opposite directions.
', 312''.'' 3. From page 6, line 15 of the specification to page 7, line 4 of the specification, ``None of the induction coils...・・・・・・
Set up. ” to be deleted. 4. Change "electromagnetic" on page 7, line 16 of the specification cylinder to "electromagnetic for heating"
and correct it. 5. Correct "induction coil 31" on page 7, line 17 of the specification to "induction coil 31b". 6. Delete "Figure 7 shows a coil." from line 6 to line 10 on page 9 of the specification tube. 7. Correct "induction coil" on page 9, line 10 of the specification to "heating induction coil." 8. Correct "Fig. 8" on page 9, line 11 of the specification cylinder to "Fig. 7." 9. Change the "induction coil 31'" on page 9, line 12 of the specification to "
Heating induction coil 31'. 10. Change “Figure 9” on page 9, line 15 of the specification cylinder to “Figure 8”
and correct it. 11. Change “Coil” on page 9, line 16 of the statement box to “Coil 3.”
1b”. 12. Delete "Fig. 3" from "Fig. 3" in line 4 on page 11 of the specification. 14. "Figure 8" on page 11, line 10 of the specification is corrected to "Figure 7." 15. "Figure 9" on page 11, line 11 of the specification is corrected to "Figure 8." 16. Amend Figure 1 of the drawings as shown in the attached sheet. 17. Amend Figure 3 of the drawings as shown in the attached sheet. 18. Amend Figure 5 of the drawings as shown in the attached sheet. 19. Amend Figure 6 of the drawings as shown in the attached sheet. 20. Amend Figure 7 of the drawings as shown in the attached sheet. 21. Amend Figure 8 of the drawings as shown in the attached sheet. 22, Patent applicant featuring Figure 9 of the drawings Kawasaki Heavy Industries, Ltd. (al Figure (b) 3)

Claims (2)

[Claims] (1) In the method of attaching a preheated metal plate to a metal frame by welding, the metal plate is heated by an induction coil placed opposite to the metal plate, and relative movement is caused between the metal plate and the metal plate. A method of heating a metal plate to be welded, the method comprising welding a metal frame to the heated metal plate. (2) A heating device for a metal plate to be welded, which is an electromagnetic induction device equipped with an induction coil that inductively heats the metal plate and causes relative movement between the metal plate and the metal plate.