JP3873597B2 - Manufacturing method of sealed contact device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sealed contact device in which a contact for interrupting current and an electrically insulating gas are arranged in an airtight space.
[0002]
[Prior art]
Various sealed contact devices have been proposed in which a fixed contact and a movable contact are arranged in a housing in which an airtight space is formed.
In the structure of the sealed contact device disclosed in Japanese Patent Laid-Open No. 9-320411, a metal lid is airtightly joined to an opening end of a ceramic container body constituting a housing. An air supply / exhaust hole is formed in the metal lid, and air in the housing is discharged from this air supply / exhaust hole or an electrically insulating gas is filled. If the air supply / exhaust holes are joined and sealed by means such as welding, the inside of the housing becomes airtight.
[0003]
In addition to this, it is known that, in a technique for joining metal materials by welding, it is possible to improve the welding strength by placing the joining surface in a hydrogen gas atmosphere or a gas atmosphere mainly containing hydrogen. Since the oxide film that exists on the joint surface and impairs the weldability is removed by the reducing action of hydrogen, a much higher welding strength can be obtained compared to welding in the atmosphere. Moreover, even if the current at the time of welding is a relatively low current condition, high strength can be obtained, and the width of the welding condition is widened.
In manufacturing the above-described sealed contact device, it has been proposed to perform the bonding step in a hydrogen gas atmosphere.
[0004]
[Problems to be solved by the invention]
In the manufacturing method of the conventional example described above, it is necessary to perform two joining steps, that is, a step of joining the metal lid to the container body and a step of sealing the air supply / exhaust hole, which is troublesome and takes time. is there.
In particular, in order to improve the airtightness of the handling and the like, if both of the two joining steps are performed by welding in the hydrogen gas atmosphere described above, the member to be welded is sealed in the airtight chamber at each joining step. An operation process for carrying in and out of the chamber, replacing the atmosphere in the chamber with hydrogen gas, or discharging the hydrogen gas is required, and the number of work steps is greatly increased.
[0005]
Furthermore, since the labor of processing to provide the air supply / exhaust holes in the container main body and the metal lid increases, there arises a problem that the cost of parts increases and the overall production efficiency is impaired.
SUMMARY OF THE INVENTION An object of the present invention is to provide a sealed contact device that achieves a reduction in process and processing cost in the manufacturing technology of the sealed contact device described above, and that is excellent in airtightness.
[0006]
[Means for Solving the Problems]
A manufacturing method of a sealed contact device according to the present invention includes a contact in an internal space formed by joining a metal base and a metal cap, and the internal space around the contact is filled with a hydrogen mixed gas. A method of manufacturing a contact device. A step (a) of disposing a metal cap and a metal base in the chamber; a step (b) in which the chamber is filled with a hydrogen mixed gas atmosphere; and a metal cap and a metal base in a hydrogen mixed gas atmosphere. (C) welding the joint.
In the step (c), it is possible to perform resistance welding by disposing a projection at one of the joint portions of the metal base and the metal cap.
[0007]
in front Step (c) Then It is possible to perform welding by interposing a brazing material between the joint portion of the metal base and the metal cap.
Before the step (c), a step (-c) of preheating the joint between the metal base and the metal cap can be further included.
[0008]
The step (-c) can be performed by filling the hydrogen mixed gas preheated in the chamber in the step (b).
The step (c) is performed by resistance welding, and the step (-c) can be preheated by pre-energizing the joint between the metal base and the metal cap.
In the step (-c), the junction between the metal base and the metal cap can be preheated by laser irradiation.
In the step (-c), the joint between the metal base and the metal cap can be thermally deformed and brought into close contact with the preheating.
[0009]
In the step (c), in the chamber maintained in an airtight state, at least one of the pair of electrodes contacting the metal base and the metal cap is moved in a direction in which the joint between the metal base and the metal cap is brought into close contact with each other. After that, the joint can be welded by energizing the pair of electrodes.
The step (b) can include a step (b-1) for bringing the chamber into a vacuum state, and a step (b-2) for filling the vacuum chamber with a hydrogen mixed gas.
The step (b) may further include a step (b-0) of bringing the inside of the chamber into a nitrogen gas atmosphere before the step (b-1).
[0010]
The temperature in the chamber can be raised in the step (b-1).
[0011]
DETAILED DESCRIPTION OF THE INVENTION
[Sealed contact device]
FIG. 1 shows the overall structure of the sealed contact device before assembly.
The sealed contact device includes a metal base 10 on which a contact component 100 is mounted and a metal cap 20.
The metal cap 20 is mainly composed of metal such as iron or stainless steel, and has a substantially rectangular parallelepiped cap shape. The opening at the lower end of the cap portion 20 has a flange portion 22 extending to the outer periphery, and the lower surface of the flange portion 22 serves as a joint portion with the metal base 10. The metal cap 20 may be entirely made of metal, or a part of the metal cap 20 may be made of a material other than metal such as ceramic. However, the joint portion needs to be made of metal.
[0012]
The metal base 10 includes a substantially rectangular ceramic substrate portion 12 made of alumina oxide or the like on which the contact component 100 is mounted, and a rectangular outer peripheral frame portion 14 that is bonded to the outer peripheral upper surface of the ceramic substrate portion 12 and extends to the outer periphery. It is configured. Similar to the metal cap 20, the outer peripheral frame portion 14 is made of a metal such as iron or stainless steel. The metal cap 20 and the metal base 10 are joined by welding the upper surface of the outer peripheral frame portion 14 to the lower surface of the flange portion 22 of the metal cap 20. The metal base 10 can also be composed entirely of metal.
The contact component 100 mounted on the metal base 10 is composed of a mechanism member or component having the same structure as that of a normal contact device. If the function of a basic contact device can be fulfilled, the shape structure and arrangement of the parts to be used are not particularly limited. The basic components include, for example, a fixed contact 105, a movable contact 103 that contacts and separates from the fixed contact 103, an electromagnetic coil 107 that drives the movable contact 103, and the like. Although not shown in the figure, the same fixed contact 105 is also provided on the back side of the drawing, and the pair of fixed contacts 105 opens and closes when the movable contact 103 contacts and separates. One end of the fixed contact 105 penetrates the metal base 10 and protrudes to the back side to constitute an external terminal 109.
[0013]
By covering the metal base 10 with the metal cap 20 and joining the flange portion 22 to the outer peripheral frame portion 14, the internal space in which the contact component 100 is accommodated is sealed in an airtight state. This internal space is filled with an electrically insulating gas.
[Basic structure of manufacturing equipment]
The embodiment shown in FIG. 2 is a manufacturing apparatus that performs a joining process of the metal base 10 and the metal cap 20, and represents a portion that performs basic operations.
A pair of upper and lower electrodes 42 and 44 are provided inside the chamber 30 constituting the airtight space. A wiring 46 that leads to the outside of the chamber 30 is connected to the electrodes 42 and 44.
[0014]
The metal base 10 and the metal cap 20 are disposed between the upper and lower electrodes 42 and 44. A space 43 in which the metal cap 20 is accommodated is open on the lower surface of the upper electrode 42. A space 45 in which the metal base 10 is accommodated is opened on the upper surface of the lower electrode 44. The outer peripheral edge of the upper electrode 42 contacts the upper surface of the flange portion 22 of the metal cap 20, and the outer peripheral edge of the lower electrode 44 contacts the lower surface of the outer peripheral frame portion 14 of the metal base 10. Both or one of the electrodes 42 and 44 is attached so as to be movable in the vertical direction, and moves in a direction in which the flange portion 22 and the outer peripheral frame portion 14 are brought into close contact with each other. If the electrodes 42 and 44 are energized in a state where the flange portion 22 and the outer peripheral frame portion 14 are held in close contact with each other by the electrodes 42 and 44, the current passes through the electrodes 42 and 44, the flange portion 22 and the outer peripheral frame portion 14. Flows, resistance heat is generated at the joint between the flange portion 22 and the outer peripheral frame portion 14, and both are resistance-welded.
[0015]
A pipe 50 is connected to the chamber 30, and the inside of the chamber 30 can be evacuated or a specific gas can be supplied into the chamber 30 through the pipe 50.
[Overall structure of manufacturing equipment]
FIG. 3 shows the overall structure of the manufacturing apparatus.
Of the electrodes 42 and 44 provided in the chamber 30, the upper electrode 42 extends through the ceiling of the chamber 30 to the outside. An air cylinder 60 that can be moved up and down is disposed at the upper end of the upper electrode 12, and an operating piston 62 of the air cylinder 60 is connected to the upper electrode 12 to move the upper electrode 12 up and down.
[0016]
Between the upper end of the upper electrode 42 and the upper outer wall of the chamber 30, a bellows 32 made of elastic rubber or the like and having a bellows shape is attached. Even if there is a gap between the upper electrode 42 that moves up and down and the surrounding chamber 30, the bellows 32 ensures that the internal space of the chamber 30 is kept airtight.
A wiring 46 connected to a power source 48 is connected to the working piston 62 that is in contact with the upper electrode 42. The electric power supplied from the power supply 48 is supplied from the wiring 46 to the upper electrode 42 through the operation piston 62.
The lower end of the lower electrode 44 extends through the chamber 30 to the outside. An airtight holding member 36 such as an O-ring is disposed between the lower electrode 44 and the chamber 30. If the airtight holding member 36 has a slidable structure like an O-ring, the lower electrode 44 can be raised and lowered with respect to the chamber 30. If the hermetic holding material 36 has electrical insulation, electrical insulation between the lower electrode 44 and the chamber 30 can be achieved.
[0017]
Outside the chamber 30, a wiring 46 is connected to the lower electrode 44 through a connection member 49, and the wiring 46 is connected to a power supply 48. If the connecting member 49 has a mechanism for driving up and down as in the case of the upper electrode 42 described above, the lower electrode 44 can be moved up and down.
An insulating material 34 is provided in the middle of the side wall of the chamber 30 and is effective in ensuring insulation between the upper and lower electrodes 42 and 44.
A pipe 50 connected to the chamber 30 is connected to a vacuum pump 52 via a valve 51. The chamber 30 can be evacuated by operating the vacuum pump 52.
[0018]
Among the pipes 50, there are two branch pipes between the valve 51 and the vacuum pump 52, and each is connected to a nitrogen gas tank 54 and a hydrogen mixed gas tank 56 via a valve 53 or a valve 55. . Thereby, nitrogen gas or hydrogen mixed gas can be fed into the chamber 30.
The hydrogen mixed gas may be a gas consisting only of hydrogen or a mixed gas of hydrogen and nitrogen.
A heater 58 is wound around the outer periphery of the pipe 50 near the chamber 30. The gas flowing through the pipe 50 can be heated by operating the heater 58.
[0019]
[Basic manufacturing process]
A method of manufacturing a sealed contact device using the manufacturing apparatus described above will be described.
As shown in FIG. 3, the metal cap 20 and the metal base 10 are attached to the electrodes 42 and 44 in the chamber 30, respectively.
The valves 55 and 51 of the pipe 50 are opened, and the hydrogen mixed gas is supplied from the hydrogen mixed gas tank 56 to the chamber 30.
When the inside of the chamber 30 is in a hydrogen mixed gas atmosphere, the upper electrode 42 is lowered.
[0020]
As shown in FIG. 2, the flange portion 22 of the metal cap 20 and the outer peripheral frame portion 14 of the metal base 10 are sandwiched between the electrodes 42 and 44. When electricity is applied to the flange portion 22 and the outer peripheral frame portion 14 from the electrodes 42 and 44 while applying pressure between the electrodes 42 and 44, the contact surfaces of the flange portion 22 and the outer peripheral frame portion 14 are joined by resistance welding. The welding conditions such as the amount of current to be applied, the time, and the applied pressure are set in accordance with the material and shape of the member to be used, the required performance, and the like. Basically, it can be set in the same range as in ordinary resistance welding.
The inside of the chamber 30 is in a hydrogen mixed gas atmosphere, and the hydrogen mixed gas is also present on the joint surface between the flange portion 22 and the outer peripheral frame portion 14, so that the oxide film on the joint surface is subjected to a reducing action and is highly welded. Strength can be obtained. As a result, the airtightness of the internal space of the metal base 10 and the metal cap 20 can be improved. The occurrence of defective products due to poor welding is reduced and the product yield is improved.
[0021]
The internal space sealed between the metal cap 20 and the metal base 10 is inevitably in a state in which the hydrogen mixed gas is sealed by welding the flange portion 22 and the outer peripheral frame portion 14. The sealed contact device in which the hydrogen mixed gas is sealed exhibits an excellent contact function during use.
Since it is not necessary to provide the metal cap 20 and the metal base 10 with a special structure such as an air supply / exhaust hole, the structure of the parts is simplified and the cost of the parts is reduced.
Since the hydrogen mixed gas is sealed simultaneously with the welding of the metal cap 20 and the metal base 10, the work process is reduced and the processing cost is reduced. Since the sealing operation is performed in a state where the entire chamber 30 is in a hydrogen mixed gas atmosphere, the hydrogen mixed gas is reliably sealed in the internal space of the sealed contact device, and the manufacturing yield of the sealed contact device is improved.
[0022]
[Projection welding]
Projection welding can be employed for welding the flange portion 22 of the metal cap 20 and the outer peripheral frame portion 14 of the metal base 10.
As shown in FIG. 5 (a), a protrusion 16 serving as a projection (protrusion) is provided on the upper surface of the outer peripheral frame portion. The ridge 16 is arranged in an annular shape that extends continuously over the entire circumference of the outer peripheral frame portion 14. The cross-sectional shape of the protrusion 16 has a triangular shape with a sharp upper end. In order to process the protrusion 16 on the outer peripheral frame portion 14, press working, cutting, punching, or the like is employed.
[0023]
Similarly to the above-described embodiment, when the flange portion 22 and the outer peripheral frame portion 14 are energized with the electrodes 42 and 44 while being pressed, the flange portion 22 and the outer peripheral frame portion 14 are concentrated only on the ridge 16 portion in contact. A current flows through the flange portion 22, and the flange portion 22 and the outer peripheral frame portion 14 are welded by the same action as in ordinary projection welding. As shown in FIG. 4, the current to be energized shows a pattern in which the current value suddenly increases with the start of energization, and after the peak value Ip after tp time, the current value suddenly decreases.
As shown in FIG. 5 (b), the ridge 16 is melted and crushed, and the flange portion 22 and the outer peripheral frame portion 14 are brought into close contact with each other. The flange portion 22 and the outer peripheral frame portion 14 are welded.
[0024]
The following conditions can be adopted as specific welding conditions for projection welding.
<Welding conditions>
Pressure: 24500N (2500kgf)
Current peak value Ip: 85 kA
Energizing time tp: 20 ms
By adopting the above-described projection welding, it is not necessary to use a clamp mechanism that applies a high pressure to the joint portion during welding to bring it into close contact. Airtight welding can be completed in a relatively short time.
[0025]
In the above embodiment, the ridge 16 is provided on the upper surface of the outer peripheral frame portion 14. However, the ridge 16 is provided on the lower surface of the flange portion 22, or the ridge 16 is provided on both the outer peripheral frame portion 14 and the flange portion 22. You can also keep it.
The arrangement structure of the projection is not limited to the above embodiment, and a technique adopted in normal projection welding can be applied.
[Welding with brazing material]
A brazing material can be used for welding the metal base 10 and the metal cap 20.
[0026]
As shown in FIG. 6, a thin sheet-like brazing material 70 is disposed between the flange portion 22 and the outer peripheral frame portion 14. As the brazing material 70, a brazing material such as BAg8 defined in the JIS standard can be used.
When the upper and lower electrodes 42, 44 are energized while pressing the flange portion 22, the brazing material 70 and the outer peripheral frame portion 14, the brazing material 70 generates heat and melts by resistance heating, and the flange portion 22 and the outer peripheral frame portion 14 are connected. Weld.
When welding the joint portions directly, the materials themselves of the flange portion 22 and the outer peripheral frame portion 14 must be melted, so that they must be heated to a temperature higher than the melting temperature of the material, whereas welding using a brazing material Then, since the brazing filler metal 70 having a relatively low melting point is melted, welding can be performed even at a low temperature that does not melt the material of the joint portion itself.
[0027]
For example, when copper, aluminum, copper alloy or the like having good thermal conductivity is used as the material of the metal base 10 or the metal cap 20, in normal resistance welding or laser welding, the heat supplied to the joint at the time of welding is ambient. It is difficult to raise the temperature to a temperature at which the material melts at the joint, and welding is very difficult. However, if welding is performed through the brazing material described above, even such a highly heat-conductive material can easily and reliably achieve hermetic joining.
In addition, also in welding with a brazing material, the hydrogen mixed gas functions as a reducing gas for reducing the oxide film at the joint portion because the inside of the chamber 30 is in a hydrogen mixed gas atmosphere.
[0028]
In the above embodiment, the method of melting and joining the brazing material by resistance heating using the electrodes 42 and 44 has been described. However, the brazing material can be melted and welded by laser heating described later. In addition, it is possible to combine apparatuses and working conditions employed in welding or brazing techniques using ordinary brazing materials.
[Laser welding]
Instead of resistance welding using the electrodes 42 and 44, welding by laser irradiation can be employed.
As shown in FIG. 7A, the metal base 10 is placed on the mounting table 82 provided inside the chamber 30, and the metal cap 20 is put on the metal base 10.
[0029]
A clamp jig 84 that clamps the metal cap 20 and the metal base 10 by elastically applying a pressing force from above to below is disposed on the upper surface of the metal cap 20. Due to the pressing force of the clamping jig 84, the flange portion 22 and the outer peripheral frame portion 14 are brought into close contact with each other and pressed.
On the ceiling wall of the chamber 30, a laser emitting unit 80 connected by an optical fiber 81 is attached to a laser irradiation device (not shown). The portion where the laser emitting unit 80 penetrates the ceiling wall of the chamber 30 has an airtight structure.
[0030]
Laser light L is irradiated downward from the laser emitting unit 80 and hits the joint between the flange portion 22 of the metal cap 20 and the outer peripheral frame portion 14 of the metal base 10. The portion irradiated with the laser beam L is heated and heated. By setting the focal position of the laser beam L at the joint position between the flange portion 22 and the outer peripheral frame portion 14, the laser energy is intensively supplied to the joint portion to efficiently heat the joint portion, It can be melted and welded.
In order to perform welding in a ring shape along the outer periphery of the metal cap 20, the irradiation position of the laser beam L is moved along the ring-shaped joint. The movement of the laser beam L can be achieved by mechanically moving the laser emitting unit 80. For example, in the case of a sealed contact device having a rectangular parallelepiped shape, a rectangular joint portion is disposed along the outer periphery of the metal cap 20, so that the laser emitting unit 80 that is linearly movable along each side of the joint portion. Should be placed. It is also possible to move one laser emitting unit 80 linearly and bent along the rectangular outline of the joint. The irradiation position can also be moved by changing the irradiation angle of the laser light L while the laser emitting unit 80 is fixed.
[0031]
The welding conditions in laser welding can be set as appropriate within the range employed in normal laser welding. For example, the following welding conditions can be employed.
<Welding conditions>
Laser type: Pulsed YAG
Energy: 15J / pulse
Number of repetitions: 10pps
Pulse width: 10 ms
Df: 0
Movement speed: 1mm / sec
If the laser welding described above is employed for joining the metal base 10 and the metal cap 20, a mechanism such as an electrode necessary for the resistance welding described above becomes unnecessary. By changing the irradiation path of the laser beam L in accordance with the arrangement structure of the joints to be welded, it is possible to relatively easily cope with sealed contact devices having different dimensional shapes.
[0032]
(Laser transmission part)
When performing laser welding, the entire laser irradiation apparatus can be installed outside the chamber 30.
As shown in FIG. 7B, the ceiling wall of the chamber 30 is constituted by a laser transmitting portion 86 made of a laser transmitting material such as glass. An airtight structure is provided between the laser transmitting portion 86 and the surrounding wall structure.
Laser light L emitted from a laser irradiation device (not shown) is irradiated from above the laser transmitting portion 86 into the chamber 30 through an optical system such as a lens and a mirror. The laser beam L irradiated into the chamber 30 is irradiated onto the joint between the metal base 10 and the metal cap 20 and laser welding is performed.
[0033]
Also in this method, the welding conditions for laser welding can be set in the same range as in ordinary laser welding. The specific conditions exemplified in the previous section can also be adopted.
In the above-described embodiment, the laser transmitting portion 86 is only provided in a part of the wall structure of the chamber 30, and other structural portions for laser irradiation may be installed outside the chamber 30. Equipment related to laser irradiation is simplified. The airtight structure of the chamber 30 is also simplified. Work such as inspection and maintenance of the laser irradiation device can be easily performed.
[Preheating of joints]
Welding can be performed after preheating the joint between the metal base 10 and the metal cap 20.
[0034]
The joint between the metal base 10 and the metal cap 20, specifically, the lower surface of the flange portion 22, the upper surface of the outer peripheral frame portion 14, and the vicinity thereof are heated to a preheating temperature of about 500 to 800 ° C. The hydrogen reduction reaction on the surface of the part easily occurs. When the hydrogen reduction reaction occurs favorably, the oxide on the surface of the joint can be efficiently removed and reduced. As a result, the welding strength is improved and a highly airtight joint is possible.
[Preheating of hydrogen mixed gas]
As a method for preheating the joint, a hydrogen mixed gas can be preheated.
[0035]
As shown in FIG. 3, when the heater 58 installed in the pipe 50 for supplying the hydrogen mixed gas into the chamber 30 is operated, the hydrogen mixed gas supplied into the chamber 30 is heated.
The heated hydrogen mixed gas is brought into contact with the metal base 10 and the metal cap 20 to raise the temperature. As a result, the joint between the metal base 10 and the metal cap 20 is preheated.
In this method, since the hydrogen mixed gas directly contacts and transfers heat to the joint to be welded, the heating efficiency is high and the preheating can be performed quickly.
[0036]
[Preheating by pre-energization]
When resistance welding or projection welding using the electrodes 42 and 44 is performed, preliminary joining can be performed to preheat the joint.
In normal welding, a current value or electric energy that generates energy sufficient to melt the materials to be joined is supplied.
On the other hand, in preliminary energization, energy lower than the energization energy at the time of welding described above is supplied to the joint. The material of the joint is heated by resistance heating and preheated. However, the joint is not melted.
[0037]
In this method, since only the vicinity of the interface of the joint that causes resistance heat generation is locally preheated, the heating efficiency is high and energy is not wasted. Since it is not necessary to provide a special mechanism or device for preheating, the facility is simple. Since the same operation as welding is performed only by changing the amount of energization, preheating work is simple. The transition from the preheating process to the welding process can be performed continuously, and the working time is shortened.
Specific examples of processing conditions for the preheating step are shown below.
<Preheating conditions>
Pressure: 24500N (2500kgf)
Current peak value Ip: 60 kA
Energizing time tp: 50 ms
It is also possible to combine the preheating of the hydrogen mixed gas and the preheating by preliminary energization as described above. Moreover, preheating by pre-energization can also be applied in the case of welding with a brazing material.
[0038]
[Preheating by laser irradiation]
The preheating of the joining portion described above can be performed by laser irradiation.
If the laser beam is irradiated onto the bonded portion with energy lower than the laser beam energy supplied when laser welding the bonded portion, the bonded portion is preheated.
The energy density at the irradiation position of the laser beam is highest at the focal position and becomes weaker as the distance from the focal position increases. Naturally, when performing welding, a focal position having a high energy density is arranged at or near the joint. By moving the focal position slightly upward or downward from the joint, the energy density supplied to the joint can be lowered and energy suitable for preheating can be supplied. The focal position of the laser beam can be easily changed by operating an optical system disposed in the irradiation path. Further, the energy supplied to the irradiation position can be weakened by increasing the moving speed of the laser beam or shortening the irradiation time at one place.
[0039]
Also in the case of preheating by laser irradiation, similarly to the preheating by the pre-energization described above, only the joint can be locally efficiently preheated, and the transition from the preheating process to the welding process can also be continuously performed. .
Specific examples of processing conditions for the preheating step are shown below.
<Preheating conditions>
Laser type: Pulsed YAG
Energy: 10J / pulse
Number of repetitions: 10pps
Pulse width: 10 ms
Df: + 10mm
Movement speed: 5mm / sec
Number of laps: 3 laps
The preheating method by laser irradiation described above can be used in combination with other preheating methods such as the preheating of the hydrogen mixed gas.
[0040]
[Thermal deformation of the joint]
With the above-described preheating, the joint portion can be thermally deformed to improve the adhesion or integrity of the joint portion.
As shown in FIG. 8A, the housing recess 15 is provided in the outer peripheral frame portion 14 of the metal base 10 slightly inside the outer peripheral edge portion. The flange portion 22 of the metal cap 20 is accommodated in the accommodating recess 15. The depth of the housing recess 15 is approximately the same as the thickness of the flange portion 22. The inner shape of the housing recess 15 is one turn larger than the outer shape of the flange portion 22.
[0041]
Therefore, when the metal cap 20 is disposed on the metal base 10, the flange portion 22 of the metal cap 20 is easily inserted into the housing recess 15 of the metal base 10. In addition, the metal cap 20 and the metal base 10 are substantially positioned by the engagement between the housing recess 15 and the flange portion 22.
The metal base 10 and the metal cap 20 having such a structure are preheated and welded by laser irradiation.
As shown in FIG. 8 (a), the laser beam L from above the flange portion 22 of the metal cap 20. ₀ Irradiate. Laser light L in this case ₀ Is a preheating laser beam L having a lower density of energy supplied to the joint than the laser beam L used for welding. ₀ It is. In this case, the laser beam L ₀ The focal position is set in a space slightly above the joint. The specific preheating conditions can employ the conditions exemplified in the previous section.
[0042]
Laser light L ₀ The flange portion 22 irradiated with is heated and heated to cause thermal expansion. Not only the flange portion 22 but also the outer peripheral frame portion 14 of the metal base 10 below it is preheated. ₀ The flange portion 22 to which is directly irradiated is heated more strongly than the outer peripheral frame portion 14, becomes a high temperature, and causes a large thermal expansion.
As shown in FIG. 8 (b), the flange portion 22 that is thermally expanded larger than the outer peripheral frame portion 14 extends to the outer peripheral side, and the outer peripheral end of the flange portion 22 is formed on the inner wall of the housing recess 15 of the outer peripheral frame portion 14. It comes into contact and is pressed strongly and comes into close contact.
[0043]
Thereafter, the laser beam L for welding is irradiated to the close contact portion between the outer peripheral end of the flange portion 22 and the inner wall of the housing recess 15. The close contact portion between the outer peripheral end of the flange portion 22 and the inner wall of the housing recess 15 is melted and joined. Specific welding conditions may be the same as those of the laser welding embodiments described in the previous section.
In this method, even if a large pressure is not applied between the metal cap 20 and the metal base 10 by the clamping jig 84 or the like, the outer peripheral end of the flange portion 22 that is a joint portion is accommodated by performing a preheating process. The inner wall of the recess 15 is in good contact with the inner wall, and good bonding can be achieved by welding.
[0044]
If a material having a smaller coefficient of thermal expansion than the material of the metal cap 20 is used for the outer peripheral frame portion 14 of the metal base 10, the difference in the amount of thermal expansion described above becomes large, and the adhesion between the flange portion 22 and the housing recess 15 is increased. Can be increased. Even if the mounting table 82 with which the outer peripheral frame portion 14 of the metal base 10 abuts is made of a material or structure having a good heat dissipation property so that the temperature of the outer peripheral frame portion 14 is not easily raised, the flange portion 22 and the outer peripheral frame portion 14. The above-mentioned adhesion can be increased by increasing the difference in the amount of thermal expansion. Furthermore, if the outer peripheral frame portion 14 is positively cooled, the difference in thermal deformation amount between the flange portion 22 and the outer peripheral frame portion 14 becomes larger, and the adhesion effect is further improved.
[0045]
[Vacuum exhaust in chamber]
The explosion-proof property can be improved by adding a step of evacuating the interior of the chamber 30 before making the chamber 30 into a hydrogen mixed gas atmosphere.
The explosion limit of hydrogen gas is a concentration of 4% to 75%. Therefore, it is effective in increasing the explosion-proof property to prevent the above-described hydrogen gas explosion from occurring in the process in which the inside of the chamber 30 is in a hydrogen mixed gas atmosphere.
In the step of supplying the hydrogen mixed gas into the chamber 30, there may be a gas such as the atmosphere in the chamber 30 at the start of the supply of the hydrogen mixed gas. By supplying the hydrogen mixed gas, the atmosphere and the like are expelled, and the concentration of the hydrogen mixed gas gradually increases. In this process, there is a possibility that the concentration of the hydrogen mixed gas falls within the explosion limit described above.
[0046]
Therefore, in the apparatus shown in FIG. 2, after the metal base 10 and the metal cap 20 are mounted in the chamber 30, the valve 51 is opened and the pump 52 is driven to evacuate the chamber 30. If the inside of the chamber 30 is in a vacuum state of, for example, a vacuum degree of 300 Torr or more, the pump 52 is stopped. The valve 55 is opened to supply the hydrogen mixed gas from the hydrogen mixed gas tank 56 to the chamber 30.
According to this method, since the hydrogen mixed gas is supplied after the inside of the chamber 30 is evacuated, the concentration of the hydrogen mixed gas in the chamber 30 can be prevented from entering the explosion limit. As a result, the explosion-proof property is enhanced.
[0047]
The embodiment of FIG. 2 is a case where resistance welding using the electrodes 42 and 44 is performed, but even when laser welding as shown in FIG. 7 is employed, a hydrogen mixed gas is used. In some cases, it is useful to go through the vacuum state described above.
[Nitrogen gas filling]
It is effective to fill the chamber 30 with nitrogen gas before the step of bringing the chamber 30 into a hydrogen mixed gas atmosphere or the step of bringing the chamber 30 into a vacuum state before that.
In the apparatus shown in FIG. 2, after the metal base 10 and the metal cap 20 are mounted in the chamber 30, the valves 51 and 53 are opened to supply nitrogen gas from the nitrogen gas tank 54 into the chamber 30. Nitrogen gas comes into contact with the metal base 10 and the metal cap 20, particularly the surfaces of the joints of the flange portion 22 and the outer peripheral frame portion 14, thereby removing moisture and adsorbed gas adhering to the surface. Also, moisture and adsorbed gas are removed from the surface of the contact component 100 mounted on the metal base 10.
[0048]
Moisture and adsorbed gas are factors that impair the welding strength and bondability at the joint, and by removing the moisture and adsorbed gas with nitrogen gas, the bonding performance and airtightness can be improved. By removing moisture and adsorbed gas from the surface of the contact component 100, it is possible to improve the contact switching characteristics when using the sealed contact device.
After moisture and adsorbed gas are removed by filling with nitrogen gas, the chamber 30 can be evacuated by closing the valve 53 and operating the pump 52. Furthermore, the valve 55 can be opened to fill the chamber 30 with the hydrogen mixed gas.
[0049]
[Evacuation and temperature rise]
It is effective to raise the temperature in the chamber 30 in the process of evacuating the chamber 30.
In the apparatus shown in FIG. 2, the chamber 30 is provided with heating means such as a heater.
When the inside of the chamber 30 is evacuated and heated, the moisture and adsorbed gas adhering to the surfaces of the metal base 10 and the metal cap 20 easily fall off from the adhering surfaces. Moisture and adsorbed gas are carried out of the chamber 30 together with the gas to be evacuated.
[0050]
As a result, as described above, it is possible to improve the welding performance by removing moisture and adsorbed gas and to improve the contact opening / closing performance when using the sealed contact device.
In addition, although the cleaning effect which removes a water | moisture content and adsorption gas increases so that temperature to raise is high, there exists a possibility of causing quality degradation of the contact component 100 grade | etc.,. Therefore, the temperature rise temperature is set in consideration of these conditions. Specifically, it is preferable to set in the range of 50 to 100 ° C.
In addition, if hydrogen gas is present in the chamber 30, the explosion-proof property is lowered by the temperature rise. If the degree of vacuum at the time of raising the temperature is set to 300 Torr or less, the explosion-proof property can be maintained well.
[0051]
【The invention's effect】
The method of manufacturing a sealed contact device according to the present invention includes sealing a hydrogen mixed gas simultaneously with hermetic welding by welding a joint between a metal cap and a metal base disposed in a chamber in a hydrogen mixed gas atmosphere. Is done.
As a result, the hermetic joining process can be reduced, the processing cost can be reduced, and the product yield can be improved. Since no air supply / exhaust hole is required in the part, the part cost is reduced. Due to the reducing action of the hydrogen gas mixture, good welding becomes possible.
[Brief description of the drawings]
FIG. 1 is a front view of an embodiment of the present invention before assembly of a sealed contact device
FIG. 2 is a cross-sectional view showing the basic structure of a manufacturing apparatus
FIG. 3 is a cross-sectional view showing the overall structure of the manufacturing apparatus
FIG. 4 is a graph showing changes in energization current
FIG. 5 is a cross-sectional view showing a step-by-step process of projection welding
FIG. 6 is a cross-sectional view showing welding using a brazing material
FIG. 7 is a sectional view showing laser welding.
FIG. 8 is a sectional view showing a method for thermally deforming a welded portion.
[Explanation of symbols]
10 Metal base
12 Ceramic substrate
14 Outer frame
16 ridges
18 Melting part
20 Metal cap
22 Flange
30 chambers
32 Bellows
42, 44 electrodes
48 power supply
50 piping
52 Pump
54 Nitrogen gas tank
56 Hydrogen mixed gas tank
58 Heater
60 Air cylinder
70 Brazing material
80 Laser emission unit
84 Laser transmission part
100 contact parts
L Laser light

Claims (10)

A method of manufacturing a sealed contact device having a contact in an internal space formed by joining a metal base and a metal cap, and the internal space around the contact filled with a hydrogen mixed gas,
Placing a metal cap and a metal base in the chamber (a);
A step (b) of making the inside of the chamber a hydrogen mixed gas atmosphere;
Look including the step (c) welding the joint portion between the metal cap and the metal base Ichisu hydrogen mixed gas atmosphere,
In the step (c) , a projection is arranged at any one of the joint portions of the metal base and the metal cap, and the pair of electrodes corresponding to the metal base and the metal cap is kept in a chamber maintained in an airtight state. At least one of them is moved in a direction in which the joint portion of the metal base and the metal cap is brought into close contact with each other, and then the joint portion is welded by energizing the pair of electrodes.
The manufacturing method of the sealing contact apparatus characterized by the above-mentioned . The method according to claim 1, wherein the step (c), between the junction of the metal base and the metal cap, is interposed brazing material to welding, method for producing a sealed contact device. 3. The method of manufacturing a sealed contact device according to claim 1, further comprising a step (-c) of preheating a joint portion between the metal base and the metal cap before the step (c). The method according to claim 3, wherein step (-c) is, the step (b) the played by filling a preheated hydrogen mixed gas into the chamber, the manufacturing method of the sealed contact device. The method according to claim 3, wherein in step (c), carried out by resistance welding, wherein the step (-c) is preheated and pre-energized at the junction between the metal base and the metal cap, sealed contact Device manufacturing method. 4. The method of manufacturing a sealed contact device according to claim 3 , wherein in the step (-c) , the joint between the metal base and the metal cap is preheated by laser irradiation. 7. The method of manufacturing a sealed contact device according to claim 6 , wherein, in the step (-c) , the joint between the metal base and the metal cap is thermally deformed and brought into close contact with the preheating. The method according to any one of claims 1 to 7 , wherein the step (b) includes a step (b-1) of bringing the chamber into a vacuum state, and a step of filling the vacuum chamber with a hydrogen mixed gas ( b-2) and a manufacturing method of a sealed contact device. The method according to claim 8, wherein step (b), prior to the step (b-1), further comprising the step (b-0) to the chamber has a nitrogen gas atmosphere, the sealed contact device Production method. The method according to claim 8 or 9, wherein the step (b-1) raising the temperature of the chamber, the manufacturing method of the sealed contact device.

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