JP5156266B2 - Welding apparatus and welding method - Google Patents

Description

  The present invention relates to a welding apparatus and a welding method using high frequency.

  Welding is the work of fusing two or more members at the molecular atom level and integrating them, and the technology to fuse the joints by heating the members or applying pressure so that the joints have continuity It is. Welding is usually performed by melting the base material. The base material is often a metal, but plastic or ceramics may be welded.

  The main welding methods are arc welding or spot welding, and spot welding is often used in the field of automobiles and sheet metal. When melting metal, it must be welded at a fairly high temperature, and it is dangerous to let untrained engineers handle it. For mass production of the same product, devices such as welding robots are often used, and in most cases, high-mix, low-volume production involves skilled workers welding each product. In particular, welding with high difficulty is only completed by humans, and a high skill level is required for welding technicians.

In such a technical field of welding, a microwave may be used (see Patent Document 1 and Patent Document 2). In the plasma welding method described in Patent Document 1 or Patent Document 2, a microwave is introduced into a microwave transmission tube from a high-frequency microwave source through a waveguide, and a process gas in the microwave transmission tube is ignited without an electrode. In this way, plasma is generated and welding is performed with a jet of plasma emitted from a metal nozzle. In this way, the welding speed is increased.
JP-T-2004-523869 JP-T-2004-535937

  The apparatus described in the above patent document requires a gas for generating arc plasma, and requires a gas discharge nozzle and torch. And it is expensive to prepare such a device. In the case of producing a single product in large quantities, the welding speed is important, and an apparatus as described in the patent literature is easily used. However, in the production of a small variety of products, the welding speed of the apparatus is not a big problem. In the production of a small quantity and a wide variety, it is not possible to make a cost adjustment if a welding control device is prepared.

  In addition, the welding work involves danger, so it is necessary for the welding engineer to become accustomed. Especially when welding a member with a fine structure such as a thin tube or a special shape, the welding engineer has advanced technology. Required technical skill is required. However, the number of engineers skilled in welding is limited, and the demand for welding cannot be easily met. On the other hand, in small and medium enterprises having a large number of welding engineers, technical succession is a problem, and it is not easy to increase the number of skilled welding engineers in the future.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a welding apparatus and a welding method capable of performing welding simply and safely even by an engineer without skilled skills. And

  (1) In order to achieve the above object, a welding apparatus according to the present invention irradiates a pair of conductive fiber blocks placed opposite to each other without contacting each other, and the pair of conductive fiber blocks with high frequency. A high-frequency irradiation section, and welding a workpiece to be welded between the pair of conductive fiber blocks by heat generated when the pair of conductive fiber blocks are irradiated with the high frequency. It is a feature.

  As described above, the welding apparatus of the present invention irradiates a pair of conductive fiber blocks placed facing each other without contacting each other with high frequency, and performs welding by heat generated between them. Only the region sandwiched between the conductive fiber blocks is high temperature, which is safe for engineers. Further, by placing the work piece between the conductive fiber blocks as described above, even an unskilled engineer can perform welding easily and safely. For example, welding can be easily performed even when a member having a fine shape or a special shape is welded. In addition, it is not necessary to prepare a control device for products of a wide variety and in small quantities, and various members can be welded at low cost.

  (2) Further, the welding apparatus according to the present invention is characterized in that the pair of conductive fiber blocks are each formed in a plate shape. Thereby, discharge can be generated between the plate-shaped main surfaces of the pair of conductive fiber blocks, and heat can be generated uniformly. As a result, uniform welding can be performed on the member.

  (3) Moreover, in the welding apparatus according to the present invention, when the pair of conductive fiber blocks are arranged with an interval of 1 mm to 30 mm, and the pair of conductive fiber blocks are irradiated with the high frequency. Is characterized by welding the objects to be welded installed at the intervals. Thus, in the welding apparatus of this invention, a pair of conductive fiber block is arrange | positioned at intervals of 1 mm or more and 30 mm or less. Thereby, it is possible to generate electric discharge between the conductive fiber blocks and generate heat necessary for welding.

  (4) Further, in the welding apparatus according to the present invention, the pair of conductive fiber blocks are fibers having a diameter of 1 μm or more and 0.1 mm or less, and an average interval between adjacent fibers is 5 times or more the diameter of the fibers. It is characterized by being formed as 20 times or less.

  Since the pair of conductive fiber blocks are formed of fibers having a diameter of 1 μm or more and 0.1 mm or less, discharge can be generated from the tips of the fibers. In addition, since the pair of conductive fiber blocks are formed so that the average interval between adjacent fibers is 5 times or more and 20 times or less the diameter of the fiber, the heat insulation effect is improved and the conduction of the generated heat can be prevented. it can.

  (5) Moreover, the welding apparatus according to the present invention is characterized in that the pair of conductive fiber blocks are formed of carbon felt or steel wool. Since carbon felt or steel wool is easily available, a pair of conductive fiber blocks can be prepared at low cost.

  (6) Moreover, the welding apparatus which concerns on this invention is equipped with the spacer which has insulation and heat resistance between said pair of conductive fiber blocks, It is characterized by the above-mentioned. Thereby, it can endure local high temperature and it can fix so that a pair of conductive fiber block may not be short-circuited. As a result, welding can be performed easily and reliably.

  (7) Moreover, the welding method which concerns on this invention is the installation process which installs a to-be-welded object between a pair of electroconductive fiber blocks installed facing each other, without making it contact each said electroconductive fiber block, An irradiation step of irradiating the pair of conductive fiber blocks with a high frequency.

  Thus, in the welding method of the present invention, an object to be welded is installed between a pair of conductive fiber blocks installed opposite to each other, and the pair of conductive fiber blocks are irradiated with a high frequency to be generated between the two. The workpiece is welded by heat. Since welding can be performed simply by sandwiching an object to be welded between conductive fiber blocks, even an unskilled engineer can perform welding easily and safely. In addition, it is not necessary to prepare a control device for products of a wide variety and in small quantities, and various members can be welded at low cost.

  (8) Further, in the welding apparatus according to the present invention, the pair of conductive fiber blocks are formed of carbon felt or steel wool. Yes. Thereby, for example, a joined product of an organic material member and a metal member used in the field of medical equipment or the like can be easily manufactured.

  (9) Further, in the welding apparatus according to the present invention, each of the workpieces is formed in a tube shape, and the other tip is inserted into one tip of the workpiece in the installation step. It is characterized by installing the work piece. When welding pipe-shaped members by arc welding or the like, a high level of technology is required, but welding can be easily performed only by placing an object to be welded at a predetermined position and irradiating a high frequency.

  According to the welding apparatus according to the present invention, even an unskilled engineer can perform welding easily and safely. In addition, it is not necessary to prepare a control device for products of various types and small quantities, and various members can be welded at low cost.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, in order to facilitate understanding of the description, the same reference numerals are given to the same components in the respective drawings, and duplicate descriptions are omitted.

  FIG. 1 is a cross-sectional view showing the configuration of the welding apparatus 1. The welding apparatus 1 includes a high frequency irradiation device 10 and a welding unit 20. The high-frequency irradiation device 10 is a device that irradiates a target installed inside with a high frequency of a certain frequency. The welding unit 20 is a unit that applies heat to the workpiece by changing the high-frequency energy irradiated to heat while fixing the workpiece.

  The high-frequency irradiation device 10 includes a high-frequency irradiation unit 11 and a resonance chamber 14, and the high-frequency irradiation unit 11 includes an oscillator 12 and a waveguide 13. The oscillator 12 is composed of, for example, a magnetron and generates a certain high frequency by electric power supplied from a power source. As the high frequency, for example, 2.45 GHz or 13.56 MHz microwaves can be selected. However, the frequency of the high frequency is not limited to this, and may be any frequency as long as the conductive fiber blocks 21 and 22 are sufficiently discharged. Therefore, if such a condition is satisfied, the frequency of light such as laser light may be used. The waveguide 13 is a metal rectangular hollow tube, and introduces the high frequency oscillated from the oscillator 12 into the resonance chamber 14.

  The resonance chamber 14 is formed by a wall surface surrounding the hollow of the rectangular parallelepiped, and has a door (not shown) that can be opened and closed on the one wall surface. After this door is opened and the welding unit 20 is installed inside the resonance chamber 14 and the periphery is sealed, high frequency is irradiated. The dimensions of the resonance chamber 14 can be, for example, 300 mm width × 320 mm depth × 190 mm height. The dimensions of the resonance chamber 14 are not particularly limited as long as the dimensions allow the high frequency to resonate appropriately. The inner wall of the resonance chamber 14 is mainly made of metal.

  The welding unit 20 includes a pair of conductive fiber blocks 21 and 22, spacers 23 and 24, and a plasma generation preventing member 26. The pair of conductive fiber blocks 21 and 22 are disposed with the spacers 23 and 24 interposed therebetween, and the spacers 23 and 24 are disposed with the workpieces 31 and 32 interposed therebetween.

  The conductive fiber blocks 21 and 22 are each formed in a plate shape. The conductive fiber blocks 21 and 22 are arranged with their main surfaces facing each other so as not to contact each other. The distance between the conductive fiber blocks 21 and 22 is preferably 1 mm or more and 30 mm or less. By setting the interval to 1 mm or more and 30 mm or less, electric discharge is generated within the interval during high-frequency irradiation, and heat that can weld metal is generated. Then, the workpieces 31 and 32 can be welded by the heat.

  The conductive fiber block is formed of fibers having a diameter of 0.1 μm or more and 0.1 mm or less, and the average interval between adjacent fibers is preferably 5 to 20 times the diameter of the fibers. Since it is formed of such thin fibers, discharge can be generated from the tip of the fibers. Moreover, since it forms in mesh shape by making the average space | interval of adjacent fiber 5 times or more and 20 times or less of the diameter of a fiber, the heat insulation effect improves and it can prevent conduction | electrical_connection of the produced | generated heat. For example, carbon felt or steel wool can be used as the conductive fiber block. Carbon felt or steel wool is cheap and relatively easy to obtain. In particular, carbon felt can be easily shaped by cutting with scissors and is easy to handle. The conductive fiber blocks 21 and 22 are not necessarily fiber blocks, and may be sponge-like conductors.

  The conductive fiber blocks 21 and 22 need to be arranged to face each other so that a pair of them do not contact each other. Therefore, at least two or more conductive fiber blocks are required to cause discharge between the two. Although it is possible to cause discharge between the conductive fiber block and the conductive plate, it is not possible to generate sufficient heat because the discharge becomes too weak and the plate releases heat. In addition, the welding apparatus 1 does not necessarily need to have only one pair of conductive fiber blocks 21, 22, and there may be a welding apparatus 1 in which a plurality of conductive fiber blocks form a plurality of pairs.

  The spacers 23 and 24 have insulating properties and heat resistance, and fix the pair of conductive fiber blocks with a predetermined interval. The spacers 23 and 24 are arranged so that the parts to be welded 31 and 32 are joined so as not to be blocked, and the workpieces 31 and 32 are pressed and fixed. For example, the spacers 23 and 24 can be arranged so as to hold the periphery of the joint portion of the workpieces 31 and 32 using an annular ceramic member. However, the shape of the spacers 23 and 24 is not particularly limited to an annular shape, and may be a plate shape, a pellet shape, or the like. It is preferable to use ceramics such as alumina having high heat resistance as the material of the spacer. Note that the spacers 23 and 24 are not essential components of the welding unit 20, and welding can be performed without the spacers 23 and 24 when the workpiece is an insulating material. In particular, when each of the workpieces has a pipe shape, it is easy to perform welding without the spacers 23 and 24.

  The plasma generation preventing member 26 is an insulating member and is formed so as to cover the air-side surfaces of the conductive fiber blocks 21 and 22. The plasma generation preventing member 26 prevents plasma from being generated by high frequency irradiation. Thereby, high frequency energy is not taken for generation of plasma, and energy is sufficiently supplied to the discharge portion. As the plasma generation preventing member 26, for example, a glass plate or a ceramic plate can be used. The shape is not limited to a plate as long as it can prevent the generation of plasma. Further, if the influence of plasma can be ignored, the welding apparatus 1 does not necessarily need to include the plasma generation preventing member 26.

  The workpieces 31 and 32 may be metal members, a metal member and a glass member, a metal member and a ceramic member, or a metal member and an organic member. For example, a polytetrafluoroethylene member and a stainless steel member can be welded. Thereby, a member made of a material having high affinity for humans such as polytetrafluoroethylene can be easily welded, and the welding method of the present invention can be applied to a medical instrument. In addition, the possibility of application also expands in the field of engines and the like. Each workpiece is preferably a plate-like member, but may be a tubular member, a linear member, or a combination thereof. FIG. 1 shows a state in which the respective end portions of the plate-like workpieces 31 and 32 are overlapped. The overlapped portion is welded by high frequency irradiation.

  FIG. 2A is a plan view of the plate-like workpieces 31 and 32, and FIG. 2B is a side view of the plate-like workpieces 31 and 32. As shown in FIG. 2, the filler metal powder 35 is sandwiched between the workpieces 31 and 32. As the filler material powder 35, for example, a welding rod processed into powder can be used. When heating is performed with the filler powder 35 sandwiched between the welded portions, welding becomes easy. Even when the filler material powder 35 made of the same material as the workpieces 31 and 32 is used, the powder is more easily melted than the plate, so that the filler material powder 35 acts like a paste and can be welded uniformly.

  A welding method using the welding apparatus 1 configured as described above will be described below. First, the door of the resonance chamber 14 is opened, the conductive fiber block 22 is placed on the bottom surface of the resonance chamber 14, and the spacer 24 is placed thereon. Then, as shown in FIG. 2, the workpieces 31 and 32 are placed on the spacer 24 in a state where the parts to be welded are in contact with each other, and the spacer 23 is placed thereon to place the workpieces 31 and 32. Pinch. Further, the conductive fiber block 21 is installed on the spacer 23. Then, the plasma generation preventing member 26 is placed on the conductive fiber block 21 to cover the surface where the conductive fiber block 21 comes into contact with air.

  After installing the welding unit 20 in the resonance chamber 14 in this way, the door of the resonance chamber 14 is closed to seal the inside, and the welding unit 20 is irradiated with high frequency. FIGS. 3A to 3C are schematic diagrams illustrating a mechanism in which heat is generated in the conductive fiber units 21 and 22 when high-frequency waves are irradiated. As shown in FIG. 3A, the high frequency is appropriately reflected in the resonance chamber 14, and the welding unit 20 is uniformly irradiated with the high frequency. And as shown in FIG.3 (b), discharge arises between the surfaces which the electroconductive fiber units 21 and 22 irradiated with the high frequency were. Double-directional arrows in the figure indicate discharge. As shown in FIG. 3C, high-temperature heat is generated in the region R between the opposing surfaces of the conductive fiber units 21 and 22 by the discharge, and the contact portions of the workpieces 31 and 32 are welded to each other. The The temperature in the region R rises to about 1500 ° C.

  In the above embodiment, a plate-shaped workpiece is welded, but a pipe-shaped workpiece may be welded. FIG. 4 is a front view showing the pipe-shaped workpieces 41 and 42. When welding the pipe-shaped workpieces 41 and 42, they are fixed between the conductive fiber blocks 21 and 22 with the tip of one workpiece 41 inserted into the tip of the other workpiece 42. High frequency irradiation is performed. In this way, for example, welding between a ceramic tube and a glass tube and welding between a stainless tube and a resin tube are possible. When welding pipes, one end is inserted into the other end, and the joint is physically fixed, so that it is easy to fix the joint during welding.

  It is also possible to weld a wire or rod-shaped workpiece. FIG. 5 is a front view showing the workpieces 51 and 52 having a linear shape. In the workpieces 51 and 52, a portion to be welded is wound with a thin wire of the workpiece. Thus, a wire or a rod-shaped workpiece can be wound with a thin wire, and both can be welded by exposing to high heat by high frequency irradiation. For example, a wire can be wound with a thin metal wire and welded, or a metal bar can be wound with a thin wire and welded. The workpieces may have a step shape other than those having such shapes.

(Experiment 1)
An experiment was performed using the welding apparatus 1 as described above. First, the tips of two stainless steel (SUS304) plates having a width of 20 mm and a thickness of 2 mm were stacked with stainless steel of the same material sandwiched between the plates, sandwiched between alumina spacers, and further sandwiched between carbon felts. The carbon felt was irradiated with a 2.45 GHz microwave at 700 W for 50 seconds. As a result, it was confirmed that the overlapped portions of the stainless steel plates were melted and the two stainless steel plates were joined by welding.

(Experiment 2)
Next, the tip of a stainless steel (SUS304) tube with an outer diameter of 1 mm is inserted and joined to the tip of a polytetrafluoroethylene tube with an inner diameter of 1 mm, the stainless steel tube portion adjacent to the joint is sandwiched between alumina spacers, and carbon felt is further attached. I caught it. The carbon felt was irradiated with a 2.45 GHz microwave at 500 W for 20 seconds. As a result, polytetrafluoroethylene was dissolved by the heat generation of the stainless steel pipe, the pipes were welded at the contact portion, and it was possible to obtain the strength of the joint that cannot be separated by human force. For example, a welded stainless tube and polytetrafluoroethylene tube can be used for medical purposes.

(Experiment 3)
Next, the tip of a ceramic tube having an outer diameter of 20 mm was inserted and joined to the tip of a glass tube having an inner diameter of 20 mm, and the joined portion was sandwiched between alumina spacers and further sandwiched between carbon felts. The carbon felt was irradiated with a 2.45 GHz microwave at 700 W for 30 seconds. As a result, the tip portion where each pipe is in contact was welded, and the strength of the joint that could not be separated by human force could be obtained. In the case of this combination, the purpose of use that matches the strength of the glass is selected, so this level of strength is considered sufficient.

(Experiment 4)
The tips of two iron wires having a diameter of 2 mm were brought into contact with each other, wound with thin iron wires, joined, and the joint was sandwiched between alumina spacers and further sandwiched between carbon felts. The carbon felt was irradiated with a 2.45 GHz microwave at 700 W for 40 seconds. As a result, it was confirmed that the iron in the contacted portion was melted and the two wires were joined by welding. Thus, experiments proved that the welding method of the present invention is effective.

It is sectional drawing which shows the structure of the welding apparatus of this invention. (A) The top view of a plate-shaped to-be-welded object, (b) The side view of a plate-shaped to-be-welded object. (A)-(c) It is the schematic which shows the mechanism in which heat | fever arises in an electroconductive fiber unit when a high frequency is irradiated. It is a front view which shows a tube-shaped to-be-welded object. It is a front view which shows a linear workpiece.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Welding apparatus 10 High frequency irradiation apparatus 11 High frequency irradiation part 12 Oscillator 13 Waveguide 14 Resonance chamber 20 Welding unit 21, 22 Conductive fiber block 23, 24 Spacer 26 Plasma generation prevention member 31, 32 Plate-shaped to-be-welded object 35 Melting Additive powder 41, 42 Tubular workpiece 51, 52 Linear workpiece

Claims (9)

A pair of conductive fiber blocks installed facing each other without contacting each other;
A high frequency irradiation unit that irradiates the pair of conductive fiber blocks with a high frequency as an electromagnetic wave having a frequency capable of sufficiently generating a discharge in the pair of conductive fiber blocks ;
A welding apparatus that welds an object to be welded installed between the pair of conductive fiber blocks by heat generated when the pair of conductive fiber blocks are irradiated with the high frequency.   The welding apparatus according to claim 1, wherein each of the pair of conductive fiber blocks is formed in a plate shape. The pair of conductive fiber blocks are arranged with an interval of 1 mm or more and 30 mm or less,
The welding apparatus according to claim 1 or 2, wherein when the pair of conductive fiber blocks are irradiated with the high frequency, the objects to be welded disposed at the interval are welded.   The pair of conductive fiber blocks are formed of fibers having a diameter of 0.1 μm or more and 0.1 mm or less so that an average interval between adjacent fibers is 5 to 20 times the diameter of the fibers. The welding apparatus according to any one of claims 1 to 3.   The welding apparatus according to any one of claims 1 to 3, wherein the pair of conductive fiber blocks are formed of carbon felt or steel wool.   The welding apparatus according to any one of claims 1 to 5, further comprising a spacer having insulating properties and heat resistance between the pair of conductive fiber blocks. Between the pair of conductive fiber blocks installed opposite to each other, without making contact with each of the conductive fiber blocks, an installation step of installing an object to be welded;
An irradiating step of irradiating the pair of conductive fiber blocks with a high frequency as an electromagnetic wave having a frequency capable of sufficiently generating a discharge in the pair of conductive fiber blocks .   The welding method according to claim 7, wherein one of the workpieces is formed of an organic material and the other is formed of a metal.   Each of the workpieces is formed in a tube shape, and the workpiece is installed by inserting the other tip into one tip of the workpiece in the installation step. The welding method according to claim 7 or claim 8.

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