JP2003112264A - Pulse-energization joining method and equipment for small surface, and joined body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent any buckling, bending or the like by controlling the pressure on a work to be joined with high accuracy. SOLUTION: A pulse-energization joining equipment 1 for small surfaces comprises a pressure-variable pressing device 40 to relatively move at least one of energization-electrodes 33 and 34 to the other, a power source device to supply a pulse current to the energization electrodes, and a chamber which can control at least a space between the energization electrodes to a desired atmosphere, holds members having small surfaces to be jointed between the pair of energization electrodes in an abutting manner of the surfaces, and applies the pulse current of the desired voltage and current to the members to perform the temporary joining at the joining surfaces to obtain a temporarily joined body. The energization-joining equipment 1 further comprises a control device which controls the pressure of the pressing device 40 based on the value detected by a pressure sensor 61, and the control device performs the feedback control of the pressure by the pressing device by the valve determined by the material and the dimensions of the members to be joined with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse current joining method utilizing the principle of the pulse current sintering method, a joining apparatus therefor, and a joined body joined by such a joining method. Or, small chip-shaped chips (small-area circular, polygonal, or other shaped chips) or thin rods or wires can be joined together, or small members such as large area members can be joined together. TECHNICAL FIELD The present invention relates to a joining method, a joining device, and a joined body, which are carried out by utilizing the principle of pulse current sintering.

[0002]

2. Description of the Related Art A thin joint has a small joint surface as in the case where the edges of thin pipes are butted and joined at the butted ends, or when the end face of a thin rod, wire or chip is joined to another member. As a conventional method of joining members to each other, (1) a method of locally heating and melting the ends to be joined and also melting a welding auxiliary material, thereby joining the welding auxiliary materials with each other, (2) ) A method of locally irradiating a high-energy beam such as a laser beam or an electron beam around the portions to be joined to locally melt the portions, thereby joining the members together (3)
Unlike the above-mentioned welding auxiliary material, a wax material (an alloy such as Cu or Ag or an amorphous metal) made of a material different from the material to be joined is melted between the joining surfaces in a vacuum atmosphere or an inert atmosphere to join the members. It was target.

However, in the joining method of the above (1), (a) the problem that the welding auxiliary material must be used,
(B) There is a problem that the base materials of the members are deteriorated because the members to be joined are locally melted, and (c) there is a limitation on the materials of the members that can be joined to each other. Further, in the joining method of the above (2), the problem of requiring a welding auxiliary material as in the above (a) is eliminated, but the above (b) and (c)
Similarly, there is a problem that the base materials of the members are deteriorated because the members to be joined are locally melted, and the material of the members that can be joined to each other is limited. Further, (d) the joining is locally at the peripheral portion. However, there is a problem that high bonding strength cannot be obtained. Further, in the joining method of (3), since the joining is performed through the above (a) to (c) and the wax material, not only the material of the member that can be joined is limited, but also sufficient heat resistance and joining strength can be obtained. There is a problem that can not be.

[0004]

By the way, the development of various devices and the miniaturization of such devices have progressed due to the progress of technology, and new fields of use of materials have been developed. It has become necessary to firmly bond small bonding areas to each other or a large area base material with a small bonding area such as a small chip (small area circular, polygonal, or other shaped chip). It was For example, when connecting thin stainless steel pipes of a prescribed length with a sufficient joint strength in a completely hermetically sealed state, nonmagnetic pipes, solid rods (circular cross section, polygonal, other shapes) Thin bar of magnetic material, etc.
When connecting solid bar materials (bars with a circular cross section, polygonal shape, and other shapes), etc., when using tungsten carbide, cobalt-based cemented carbide materials and iron-based materials, Alternatively, it is a case where a copper-based material and an iron-based material are used by being joined together.

In recent years, by utilizing the principle of pulse current pressure sintering (including discharge plasma sintering, discharge sintering, plasma activated sintering, etc.) performed by passing a pulse current, it has a predetermined bulk instead of powder. However, a technology for joining members having relatively large joining surfaces is being developed, but with a joining device that uses this pulsed current pressure sintering method, a relatively large pressure is applied to the material. Because it was necessary, for example,
It cannot be used when the end faces of thin-walled pipes are butted against each other and the members to be joined together have a small joining surface and a large force causes the members to buckle.
In order to solve such a problem, an outer shape, a core type or a jig for preventing buckling must be used.
However, when using a mold or a jig, it is necessary to prepare a mold or jig suitable for the shape and size of the members to be bonded each time the shapes and sizes of the members to be bonded are different. There are major problems in mass production and practicality, such as a problem of complicated work, a problem of increasing the joining time and power consumption because it is necessary to energize the mold or jig, and a problem of increasing the joining cost.

The problem to be solved by the present invention is to utilize the principle of pulsed current pressure sintering including discharge plasma sintering, discharge sintering, plasma activated sintering, and the like, and yet, between members having small joint surfaces. It is an object of the present invention to provide a pulse current joining method and a joining device suitable for joining. Another problem to be solved by the present invention is to highly accurately control the pressure applied to the members to be joined by a pressing device to prevent buckling, bending, etc. of the members to be joined, high mass production and high practicality. A pulse current welding method and a welding apparatus therefor are provided.
Another problem to be solved by the present invention is to provide a joined body joined by the joining method as described above.

[0007]

One aspect of the present invention is a state in which a plurality of members having small joint surfaces to be joined to each other are placed in a chamber kept in a desired atmosphere and the joint surfaces are brought into contact with each other. In a pulsed current joining method for a small joining surface, which is sandwiched by a pair of current-carrying electrodes, and a pulse current having a desired voltage and current is applied to the plurality of members through the pair of current-carrying electrodes to join at the joining surface, energization is started. After pressing the plurality of members with a desired first pressing force, after the start of energization, after the temperature in the chamber reaches a temperature determined by the materials and dimensions of the plurality of members to be joined, the material and dimensions The plurality of members are pressed by a second pressing force determined by the above, and the plurality of members are temporarily joined to form a temporary joined body. The second pressing force may be a variable pressing force that changes appropriately. In the above-described pulsed current joining method for a small joining surface, the pressing force applied by the second pressing force may be controlled by constantly detecting the pressing force applied to the member by a pressure sensor and feeding it back. The joint surface may be polished to a mirror surface. Moreover, the pulse current joining method for a small joining surface may further include heat-treating the temporarily joined member at a temperature and a time determined by the material and size of the member. Furthermore, in the pulse current joining method for the small joining surface, the heat treatment may be performed by applying a heat treatment current by the current-carrying electrode in the chamber subsequent to the temporary joining, or by performing a plurality of the temporary joining of the temporary joining. The bonded bodies may be collectively processed in a heat treatment furnace.

According to another invention of the present application, a pair of energizing electrodes, a pressure variable pressing device that moves at least one of the pair of energizing electrodes relative to the other, and a pulse current is supplied to the energizing electrodes. A power supply device, and a chamber capable of controlling at least the space between the current-carrying electrodes to a desired atmosphere,
A member having a small joint surface to be joined to each other between the pair of energized electrodes is sandwiched with the joint surfaces in contact with each other, and a pulse current having a desired voltage and current is applied to the member to temporarily join the joint surfaces. In a small joining surface pulse current joining device to form a temporary joined body, a pressure sensor capable of detecting the pressure applied to the members to be joined and a pressing device for pushing the pressing device based on a detection value detected by the pressure sensor. A control device capable of controlling pressure is provided, and the control device is configured to perform feedback control of the pressing force by the pressing device at a value determined by the material and size of the members to be joined. In the above-mentioned pulse current welding device for small joining surfaces, the pressure variable pressing device may be a ball screw device and an electric motor for driving the ball screw device which is capable of minute rotation control. Further, the power supply device for supplying the pulse current to the pair of energized electrodes is capable of supplying a heat treatment current to the energized electrodes, and the heat treatment current is passed to the energized electrodes after the temporary bonding to cause the heat treatment current to flow in the chamber. A heat treatment furnace may be provided to perform heat treatment, or to further perform heat treatment on the temporary bonded body. When the heat treatment is performed in the chamber, the current supplied to the current-carrying electrode may be the same as or different from the sintering current. Further, when the heat treatment is performed in the heat treatment furnace, the heat treatment furnace may be incorporated in one system or separately arranged. Note that the chamber with atmosphere control may be omitted if the material, shape, or low-temperature bonding that does not cause a problem of the material to be bonded during the bonding process is possible. Furthermore, the pulsed current joining apparatus for small joining surfaces may be further provided with a carrying device for automatically supplying the temporary joined body to the heat treatment furnace. In addition, an apparatus may be provided that automatically conveys from the TP magazine to the joining device, from the joining device to the heat treatment furnace, and further from the heat treatment furnace to the magazine for cooled or treated joined products. Another invention of the present application is a bonded body bonded by the pulse current bonding method for a small bonding surface according to claims 1 to 6.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a bonding apparatus for carrying out the method for pulse-current welding for small bonding surfaces according to the present invention will be described below with reference to the drawings. 1 to 3, there is shown a pulsed current joining apparatus for small joining surfaces (hereinafter simply referred to as an electricity joining apparatus) 1 according to the present embodiment. This current welding device 1
Uses the principle of pulsed current sintering including discharge plasma sintering, discharge sintering, plasma activated sintering, etc. , Punch, etc.) are not used. Current joining device 1
Is a frame device 10, a movable table device 20 movably supported in a vertical direction (in FIG. 1) with respect to a central portion (in FIG. 1) of the frame device 10, and a current-carrying electrode device attached to the movable table device 20. The lower energizing electrode assembly 31 of 30, the pressing device 40 for moving the movable table device up and down, the upper energizing electrode assembly 32 of the energizing electrode device 30 attached to the upper part of the frame device 10, and the surroundings of the members to be joined. And a housing assembly 50 that defines a chamber that provides a desired atmosphere (eg, a vacuum atmosphere or an inert gas atmosphere). The energization joining apparatus of this embodiment is controlled in its overall operation by the control device 60 (FIG. 3), and a DC pulse current for joining is supplied from the power supply device 70 (FIG. 3).

The frame device 10 comprises a box-shaped lower frame 1
1 and a lower support plate 12 fixed to the upper portion of the lower frame 11, and a plurality of lower support plates 12 attached to the lower support plate 12 by a known method (in this embodiment, 4 arranged near four corners of the lower support plate 4). Book support 13 and an upper support plate 14 attached to the upper end of the support 13 by a known method. Four through holes are formed in the lower support plate 12, and a bearing member 121 is mounted in the through holes. In each bearing member 121, guide shafts 22 that are attached to the four corners of the movable table 21 of the movable table device 20 by known methods and extend downward are slidably inserted. Therefore, the movable table 21 is guided by the guide shaft 22 and the bearing 122 so as to be movable only in the vertical direction.

A pressing device 40 is arranged and fixed in the lower frame 11. The pressing device 40 is a ball screw device 41 having a known structure and function that extends vertically by a predetermined length.
An electric motor 42 as a drive source for applying an input to an input shaft (not shown) of the ball screw device 41, and the electric motor 4
Transmission mechanism 4 for giving the rotation output of 2 to the ball screw device 41
3 and 3. The electric motor 42 is preferably a stepping motor capable of controlling a minute rotation angle with high accuracy. The electric motor 42 is connected to the control device 60, and its rotation is controlled under the control of the control device. A guide plate 24 is attached near the upper end (in FIG. 1) of the output shaft 411 of the ball screw device 41,
A plurality of guide rods 25 attached to the movable table 21 and extending downward are guided to the guide plate 24 so as to be relatively movable. The axis of the ball screw device 41 and the axis of the lower energizing electrode assembly 31 are 0-
Matched with 0. Movable table 21 and output shaft 411
A pressure sensor 61 of a control device 60 that controls the operation of the present energization welding device is arranged between the and. The pressure sensor 61 may have a known structure and function. Therefore, the axial pressing force applied to the movable table 21 by the pressing device 40 is detected by the pressure sensor 61. The output shaft 411 of the ball screw device does not rotate due to the action of the guide plate and the guide rod.

A lower energizing electrode assembly 31 is insulated and fixed to the upper surface of the movable table 21 with an insulating mounting plate 35 with respect to the movable table. The attachment plate 35 and the lower end of the lower energization electrode assembly 31 are fixed by a plurality of known set screws, and the attachment plate 35 is fixed to the movable table 21 by the known set screws. Lower energizing electrode assembly 3
Reference numeral 1 has a cylindrical lower current-carrying electrode 33 made of a hard and tough material such as stainless steel. The lower energizing electrode 33 can be connected to the power supply device 70 (FIG. 3) via the cable and the switch device 71 (FIG. 3). The switch device 71 may form a part of the power supply device, and may have the same structure as the switch mechanism shown in Japanese Patent Application No. 2000-284771 “Pulse energization sintering machine energization device” by the present applicant. A cooling passage (not shown) through which a cooling fluid flows is formed in the lower energization electrode 33, and the cooling fluid is circulated through the pair of supply / discharge pipes (only one is shown in FIG. 1) 331 in the cooling passage. It has become so. Mounting plate 3
5 may be entirely made of an insulating material, or may be a metal plate whose surface is subjected to an insulating treatment.

A lower housing portion 51 of the housing assembly 50 is provided outside the lower conducting electrode 33 so as to be movable relative to the lower conducting electrode 33. The lower housing portion 51 includes a bottom wall member 511 slidably attached to the outer periphery of the lower energization electrode, and an inner peripheral wall member 512 and an outer peripheral wall member that are fixed to the bottom wall member so as to be spaced apart from each other and hermetically fixed to the bottom wall member. 513 and an annular end plate 514 fixed to the upper ends of the inner and outer peripheral wall members. Bottom wall member 511
A seal member (not shown) having a known structure is provided on the contact surface with respect to the lower energizing electrode to seal the gap between them. A drive rod 53 slidably supported by a bearing 123 mounted in a through hole of the lower support plate 12 is attached to the bottom wall member 511. The drive rod is driven by a rack and pinion device and an electric motor (not shown) for rotating the pinion. This allows the lower housing portion 51 to move relative to the lower energizing electrode. Reference numeral 55 denotes a stopper which is attached to the movable table and which limits the lowering of the lower housing portion 51, and is provided at two diametrical positions about the axis 0-0. Reference numeral 57 is a sight glass made of heat-resistant glass.

A lower conducting electrode assembly 32 is fixed to the lower surface of the upper support plate 14 via a mounting plate 36 and an insulating plate 38. The fixing of the insulating plate 38 to the upper end of the lower energizing electrode assembly 32, the fixing of the insulating plate 38 and the mounting plate 36, and the fixing of the mounting plate 36 and the upper support plate 14 are performed by a plurality of known set screws. Upper energizing electrode assembly 32
Has a cylindrical upper current-carrying electrode 34 made of stainless steel. The upper energization electrode 34 can be connected to the power supply device 70 via a cable. A cooling passage (not shown) through which a cooling fluid flows is formed in the upper energization electrode 33, and a pair of supply / discharge pipes (only one is shown in FIG. 1) 3 are provided in the cooling passage.
A cooling fluid is circulated through 41.

An upper housing portion 52 of the housing assembly 50 is disposed outside the upper energizing electrode 34. The upper housing portion 52 includes a top wall member 521, which is hermetically attached to the outer periphery of the lower energization electrode by a known method, and a top wall member 5.
21 has an inner peripheral wall member 522 and an outer peripheral wall member 523 which are fixed to each other in a sealed manner with respect to the bottom wall member, and an annular end plate 524 which is fixed to lower ends of the inner and outer peripheral wall members. The top wall member 521 is fixed to the upper support plate 14 via a plurality of (four in the present embodiment, but only one is shown) connecting rods 54 fixed to the upper support plate 14. Reference numeral 56 is a pipe attached to the inner peripheral wall member 522 and the outer peripheral wall member 523, and is connected to an atmosphere control device (not shown) for making a vacuum atmosphere or an inert gas atmosphere through a conduit not shown. The upper surface of the end plate 514 of the lower housing portion 51 and the upper housing portion 52
An annular groove is formed in at least one of the lower surfaces of the end plates 524 of the respective members, and an O-ring seal is provided in the groove to prevent air from leaking between them when they are fitted together. ing. In the upper housing part 52,
As shown in FIG. 3, a pressure sensor 62 and a temperature sensor 63 are provided, and the gas pressure and temperature in the chamber C defined by the lower housing portion 51 and the upper housing portion 52 are provided by the pressure sensor and the temperature sensor. Can be detected respectively. The pressure sensor 62 and the temperature sensor 63 are connected to the control device 70, and their detection signals can be input to the control device. In addition, you may perform pressure control combined with temperature feedback.

[0016]

[Embodiment 1] Next, referring to FIG.
A case will be described where thin pipes M1 and M2 as shown in [A] are joined together with their end faces abutted. Here, the pipe M1 is made of non-magnetic stainless steel (SUS3
04), and the pipe M2 is made of magnetic stainless steel (SUS430), and each has a length L ₁
= 30 mm, inner diameter d ₁ = 8 mm, outer diameter d ₂ = 10 mm, and wall thickness t ₁ = 1 mm. In this case, the end faces of the pipes M1 and M2 that join to each other, that is, the pipe M
The upper end surface M1e of No. 1 and the lower end surface M2e of the pipe M2 are cut so as to make uniform contact over the entire surface. Preferably, the mirror surface is polished. After the two pipes thus prepared and whose end faces are butted against each other are set on the upper end face of the lower conducting electrode 33 by using, for example, a V-groove structure positioning jig, the control device 60 operates the pressing device 40. Then, the movable table 12 is raised, and the lower energizing electrode assembly 3
A pipe is sandwiched between 1 and the upper energization electrode assembly 32. At this time, the pressing force of the pressing device 40 is adjusted so that the initial pressing force is suppressed by a force of, for example, 1 to 3 megapascals so that the abutting surface is easily adapted. In this state, the lower housing part 51 is raised to move the end plate 514 to the upper housing part 5.
The second end plate 524 is brought into contact with the second end plate 524, and the housing defines a chamber C which is sealed from the outside around the members M1 and M2 to be joined.

In this state, the atmosphere control device is operated to create a desired atmosphere in the chamber C. In this case, the inside of the chamber is evacuated to a vacuum state, for example, about 6.7 pascals (Pa) (5 × 10 ^-2 torr). After the evacuation of the chamber is completed, the switch device 71 is turned on in response to a command from the control device 60, and the power supply device 70 passes through the vertical energizing electrode assembly to the pipes M1 and M2 for 6 to 1
A DC pulse current of 300 to 800 amperes (A) is applied at 2 volts (V). As the current flows, the pipe heats up and its temperature rises.Because the upper and lower parts are mechanically fixed, thermal expansion causes strain in the axial direction, the applied pressure gradually increases, and the pipe remains in the axial direction with a high pressing force. The pipe buckles when pressed against. Therefore, after fixing the pipe, the pressing force applied to the pipe by the pressing device 40 is reduced to, for example, 0.5 to 1.0 megapascal (MP), and the energization of the pulse current is started. After that, the pressing force is feedback-controlled based on the detection signal from the pressure sensor 61, and the pressing force is held. The feed mechanism of the energizing and pressurizing shaft may be incorporated with a program for fast-forwarding to the front end surface of the pipe by about 1 to 2 mm, and then decelerating until it comes into contact with the rear end surface. Since both pipes are joined in a short time of about 2 to 5 minutes from the start of energization to the pipes, the switch device is turned off to stop energization. The principle of this joining is as follows. When a direct current pulse current is applied, the contacting interface portion with high contact resistance is heated to a high temperature by Joule heating. Further, the entire material is Joule heated by the resistance value of the material itself. Further, a high pressure is generated at the contact interface between the members that are vertically stacked due to the plastic deformation and the thermal expansion due to the vertical uniaxial pressure. Further, an electric field is generated along the direction of the flow of the on-off pulse current, and electric field diffusion occurs. It is considered that this electric field diffusion effect and the mechanical pressure of the above-mentioned thermal diffusion contribute to the solid phase diffusion bonding and bring about the orientation of the metal crystal structure. Since this joining is not always performed with sufficient joining strength, it is called temporary joining here, and the temporarily joined one is called a temporary joined body. After the energization is stopped, the chamber is returned to atmospheric pressure and the lower housing part is lowered so that the temporary bonded body sandwiched between the upper and lower energizing electrodes can be taken out. After that, the movable table is lowered and the temporary bonded body is taken out between the upper and lower energizing electrodes to complete the temporary bonding. In the above case, the temporary bonded body is cooled by natural cooling, but if you want to forcibly cool it,
After the energization is stopped, a cooled inert gas may be supplied into the chamber, or a cooling stage having a heat absorbing structure member may be separately provided to cool the chamber. Although the first embodiment is a case of vertically stacked members, a plurality of pipes and solid round bars may be joined inside and outside in a coaxial cylindrical stacked shape (Baumkuchen shape or concentric shape).

When the area of the joint surface is small as in the case of joining thin pipes as described above, joining rods or wires having a small diameter, or joining rods, wires or thin pipes and plates, If a large force is applied, the members to be joined will buckle or bend even at room temperature, and if the members to be joined generate heat and become hot, they will buckle with a smaller pressing force. Therefore, various control programs (control programs that determine the pressing force decrease start temperature, pressing force, energizing time, etc.) according to the dimensions (length, outer diameter, wall thickness, etc.) and material of the members to be joined are created in advance. The pressing device 40 performs the increase / decrease feedback control of the pressing force according to the control program. Then, the pressing force of the pressing device can be controlled to a value as close to zero as possible. A flow chart of such feedback control is shown in FIG.

The joining of both pipes performed by the above-mentioned current joining device is temporary joining. Depending on the purpose of use of the pipe, there may be a case where the joining strength is about temporary joining. In that case, the temporarily joined pipes M1 and M2 are
The temporary bonded body M3 shown in [B] is taken out from the current welding apparatus and used. When the main joining of both pipes is performed with high joining strength, heat treatment is performed under the following conditions. Heat treatment temperature 900 ° C. to 1000 ° C. Heat treatment time 30 minutes to 90 minutes The above heat treatment conditions are for a temporarily joined body obtained by temporarily joining the stainless steel thin-walled pipe as a joined member, and the size, material, etc. of the joined member. It depends on

Next, the pipe M temporarily joined as described above.
A case will be described where 1 and M2 (hence the temporary bonded body M3 here) are heat-treated using the above-described current-flow bonding apparatus. After the energization for the temporary joining is completed, the vacuum atmosphere in the chamber C is maintained as it is, or an inert gas is allowed to flow in the chamber to cool the chamber C.
After the internal temperature has dropped to a temperature suitable for the heat treatment temperature, the heat treatment current for maintaining the heat treatment temperature from the power supply device 70, that is, 5 to 20 volts, 500 to 10
A direct current of 00 amps is applied for about 10 to 30 minutes. In this case, the temperature value provided in the chamber feedback-controls the current value so that the temperature in the chamber is maintained at the heat treatment temperature. This heat treatment completes the joining of the two pipes (main joining). After the heat treatment is completed, the inside of the chamber C is waited for cooling (either natural cooling or forced cooling), the lower housing part is lowered, and the movable table is lowered to take out the main joined pipes for use. Usually, since the heat treatment time is much longer than the temporary joining time, it is inefficient to perform the heat treatment using the current joining device as described above. Therefore, such heat treatment is suitable for a single product or a small amount production.

In FIG. 6, another embodiment of the current welding apparatus of the present invention is shown. The current welding apparatus further includes a heat treatment section 80 that performs heat treatment. This heat treatment part may be a heat treatment furnace of a known structure available on the market. In the case of heat treatment in this heat treatment furnace, when a plurality of pipes temporarily joined by the current joining device 1 are accumulated, they are put in a batch type heat treatment furnace and heat treated at once. Since the heat treatment takes several tens of minutes while the temporary joining can be performed in a few minutes, it is possible to improve the efficiency and improve the efficiency of the joined product by collectively performing the heat treatment on the temporarily joined temporary joined bodies. Suitable for mass production.

The electrical joining apparatus may further include a transfer device 90 for automatically supplying the temporarily joined members, that is, the temporarily joined body, to the heat treatment section 80. This transfer device includes a robot device 91 having a known structure that takes out a temporary bonded body from between the lower conductive electrodes on the current-carrying bonding device 1, and a plurality of temporary bonded bodies taken out by the robot device 91 together.
0, and a conveyor 92 for sending the paper to the inside. The robot device 91 includes an arm 911 that can swing within an angle θ and a chuck 912 attached to the tip of the arm. By performing the heat treatment on the separately provided heat treating portions, a plurality of temporary joined bodies can be collectively heat treated in a batch manner, so that the joining can be performed efficiently. Therefore, it is suitable for manufacturing a large number of joined bodies made of the same product. In addition,
Although not shown, members to be joined are supplied in a vertically stacked state by a supply conveyor provided in the middle of the swinging range of the arm 911, gripped by a chuck and automatically placed between the upper and lower energizing electrodes. It is also possible to supply the same to the electrodes and press and hold them with the current-carrying electrodes while gripping them with the chuck. Although not shown, a device for automatically carrying the TP magazine to the joining device, the joining device to the heat treatment furnace, and the heat treatment furnace to the magazine for the cooled or treated joined article may be provided.

[0023]

Example 2 A thin wire N1 as shown in FIG. 7A.
A case where the end face of the plate member and one surface of the plate member N2 are joined together will be described. Here, the wire N1 is made of molybdenum and has a length L.
₂ = 25 mm, an outer diameter d ₃ = 5 mm, the plate material N2 is made of tungsten, the thickness in the diameter d ₄ = 30 mm is t ₂ = 5 mm
It is assumed that it is a disc. In this case, the end surfaces of the wire N1 and the surface of the plate N2 that are in contact with each other are processed so as to be in uniform contact with each other. Preferably, the mirror surface is polished. The wire rod and the plate member thus prepared and butted against each other were first temporarily joined by the current joining device 1 in the same manner as in the first embodiment. At that time, it was pressed by the upper and lower energizing electrodes with a force of initial pressing of 5 megapascals.

In this state, the atmosphere control device is operated to evacuate the chamber C to create a vacuum state (5 × 10 ^-2 torr).
After setting r), set the preset pressure by the pressing device to 2
200 to 600 for 3 to 12 volts (V) on the wire and plate through the vertical energizing electrode assembly in megapascal
A direct current pulse current of ampere (A) was applied. The pipe generated heat as the current flowed and became hot, so the temperature was measured with a non-contact infrared radiation thermometer. The temperature of the joint is 1
This pressing force was maintained by feedback controlling the pressing force between 1 and 2 megapascals until it reached 350 ° C. The energization was stopped 5 minutes after the start of the energization. As a result, FIG. 7 [B]
A temporary bonded body N3 of the wire and the plate as shown in FIG. This temporary bonded body N3 is heat-treated at a temperature of 1180 ° C. for a heat treatment time of 40-
Heat treatment was performed for 60 minutes. By this heat treatment, the joining of the wire and the plate was completed. In the above example, only the joining of stainless thin pipes and joining of molybdenum wire rods and tungsten plate members were described, but in addition, joining of various members with a small joining area, and joining of members of various materials It is possible to use the method and apparatus of the present invention. For example, as shown in FIG. 8 [A], when a plurality of small-diameter columnar or cylindrical chips O2 are bonded to the substrate O1, as shown in FIG. 8 [B], a small gear P2 is attached to the disc P1. When joining
When the cam member Q2 is joined to the substrate Q1 as shown in [C], a plurality of small cams R1 to R3 having different shapes are joined adjacent to each other as shown in FIG. 8D. In this case, as shown in FIG. 8E, the small component S2 is joined to the block material S1.

[0025]

According to the present invention, the following effects can be achieved. (B) By means of the pulse current welding method, which joins members with a small joining area such as thin-walled pipes into solid-phase diffusion joining, mutual members can be easily and buckled in a completely tightly sealed state over all contact surfaces, It is possible to mass-produce high-quality bonded parts that do not cause bending deformation and have the same strength as the base material. (B) It is possible to easily join members made of different materials or the same material that cannot be joined by the conventional joining method. (C) Since the pedestal-shaped component can be manufactured by pulse-current welding a small piece of member to the substrate material without cutting the block-shaped material into a complicated shape by cutting (milling, electric discharge machining, etc.), Significant process reduction and cost reduction can be achieved. (D) It is possible to easily create an integrated shape or an undercut shape of a flat part and a protruding part having a right angle or an acute angle that cannot be cut by the end mill's cutting edge, and it is easier to make a shape design than a manufacturing process from an integrated member. Greater freedom. (E) Solid-phase diffusion bonding parts can be mass-produced easily in a short time at low cost. (F) Compared to brazed products and welded products, it is possible to make parts that are both structurally and mechanically highly reliable.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a pulsed current joining apparatus for small joining surfaces according to the present invention.

FIG. 2 is a cross-sectional view of the pulsed current joining apparatus for small joining surfaces as seen along the line AA in FIG.

FIG. 3 is a view showing a connection relationship between electric and control systems of the pulse current welding device for a small joint surface of FIG.

FIG. 4 is a perspective view showing a member and a temporary bonded body of a first embodiment that are bonded by using the pulsed current bonding apparatus for a small bonding surface of FIG.

5 is a flowchart showing feedback control of pressing force of the pulsed current welding apparatus for small welding surfaces in FIG. 1. FIG.

FIG. 6 is a view showing a modified example of the pulse current joining device for small joining surfaces of the present invention.

FIG. 7 is a perspective view showing a member and a temporary bonded body of a second embodiment that are bonded by using the pulse current welding device for a small bonding surface of FIG.

FIG. 8 is a schematic perspective view showing another example of joining using the pulse current joining device for small joining surfaces. DESCRIPTION OF SYMBOLS 1 pulse energization joining device 10 frame device 20 movable table device 21 movable table 30 energizing electrode device 31 lower energizing electrode assembly 32 upper energizing electrode assembly 33 lower energizing electrode 34 upper energizing electrode 40 pressing device 50 housing 51 lower housing part 52 upper Housing part 60 Control device 61 Pressure sensor 62 Pressure sensor 63 Temperature sensor 70 Power supply device 71 Switch device 80 Heat treatment part 90 Transfer device

Claims (12)

[Claims] 1. A plurality of members having small bonding surfaces to be bonded to each other are placed in a chamber maintained in a desired atmosphere and sandwiched by a pair of energizing electrodes in a state where the bonding surfaces are in contact with each other. In a pulsed current joining method for a small joining surface, in which a pulsed current having a desired voltage and a current is applied to a member through the pair of energizing electrodes to join at the joining surface, the method is performed with a desired first pressing force before starting energization. After pressing a plurality of members, the temperature in the chamber after the start of energization reaches a temperature determined by the materials and dimensions of the plurality of members to be joined,
A pulsed current joining method for a small joining surface, characterized in that the plurality of members are pressed with a second pressing force determined by the material and size, and the plurality of members are temporarily joined to form a temporary joined body. 2. The method of pulse current welding for a small joint surface according to claim 1, wherein the pressing force applied to the member is constantly detected by a pressure sensor to feed back the pressing force with the second pressing force. Controlled pulse current welding method for small joint surfaces. 3. The pulse current welding method for a small joint surface according to claim 1, wherein the joint surface is polished into a mirror surface. 4. The pulse current joining method for a small joining surface according to claim 1, 2 or 3, further comprising heat-treating the temporarily joined member at a temperature and a time determined by the material and size of the member. A method for pulse current welding for small joint surfaces, characterized by. 5. The pulse current joining method for a small joining surface according to claim 4, wherein the heat treatment is performed by causing a heat treatment current to flow in the chamber in the chamber subsequent to the temporary joining. Pulse current welding method for small joint surfaces. 6. The small joint surface pulse energization joining method according to claim 4, wherein the heat treatment is performed by collectively using a heat treatment furnace for the plurality of temporarily joined temporary joined bodies. Energization welding method for. 7. A pair of energizing electrodes, a pressure variable pressing device that moves at least one of the pair of energizing electrodes relative to the other, and a power supply device that supplies a pulse current to the energizing electrodes. A chamber capable of controlling the space between the current-carrying electrodes to a desired atmosphere, and sandwiching a member having small bonding surfaces to be bonded to each other between the pair of current-carrying electrodes with the bonding surfaces in contact with each other, In a pulsed current joining device for a small joining surface, in which a pulse current of a desired voltage and current is applied to a member to temporarily join the joining surfaces to form a temporary joined body, a pressure capable of detecting the pressure applied to the members to be joined A sensor and a control device capable of controlling the pressing force of the pressing device based on a detection value detected by the pressure sensor, the control device pressing force by the pressing device, the material of the member to be joined and Small joint surface pulse current welding apparatus feedback control value determined by law. 8. The small joint surface pulse current welding device according to claim 7, wherein the pressure variable pressing device is a ball screw device and an electric motor for driving the ball screw device which is capable of minute rotation control. Pulse energizing welding equipment. 9. The pulse current welding apparatus for a small welding surface according to claim 7, wherein the power supply device that supplies the pulse current to the pair of current-carrying electrodes is capable of supplying a heat treatment current to the current-carrying electrodes. A pulsed current welding apparatus for small welding surfaces, in which the heat treatment current is passed through the current-carrying electrode to perform heat treatment in the chamber after the temporary welding. 10. The pulse current welding apparatus for small joint surfaces according to claim 7 or 8, further comprising a heat treatment furnace for performing heat treatment on the temporary joint body. 11. The pulse current welding apparatus for a small bonding surface according to claim 10, further comprising a conveying device that automatically supplies the temporary bonded body to the heat treatment furnace. 12. A joined body joined by the pulse current joining method for a small joining surface according to claim 1.