JP3789464B2 - Soldering device - Google Patents

Description

  The present invention relates to a jet-type soldering apparatus, and in particular, when soldering a coil portion such as a transformer or a choke coil used in an electronic device, or when soldering a printed circuit board after mounting an electronic component, molten solder in a solder bath The present invention relates to a soldering apparatus that can maintain an overflowing state in which no oxide is mixed.

Conventional soldering apparatuses include a jet type and a pumping type. As the jet type, one described in Japanese Patent Application Laid-Open No. 59-147772 of Patent Document 1 is known, and is shown in FIG.
In FIG. 19, when compressed air is supplied from the air pipe 7 above the pressure chamber 3, the liquid level of the molten solder 10 in the pressure chamber 3 is pushed downward. At this time, since the check valve 9 provided in the return pipe 8 is closed by the pressure in the pressure chamber 3, the molten solder 10 in the pressure chamber 3 passes through the solder feed pipe 5 and is sent out from the nozzle 6 at the upper end. The object to be soldered is soldered by the molten solder fed from the nozzle 6. Then, when the soldering of the soldered body is completed, the supply of compressed air into the pressure chamber 3 is stopped, and a four-way valve (not shown) provided in the middle of the air pipe 7 is closed. As a result, the pressure in the pressure chamber 3 is reduced, the check valve 9 provided in the return pipe 8 is opened, and the molten solder 10 sent out from the nozzle 6 passes through the check valve 9 by the return pipe 8. Return to 3.

Further, in the jet type soldering apparatus, as a means for pushing down the liquid level of the molten solder 10, a cylinder is attached in place of the air pipe 7, and a piston or a fan is arranged in the cylinder without interposing compressed air. A configuration is also known in which the molten solder 10 is directly fed in (Patent Document 3).
On the other hand, as a pumping type soldering apparatus, one described in Japanese Patent Application Laid-Open No. 11-5155 of Patent Document 2 is known, and is shown in FIG.
In FIG. 20, a pumping type soldering apparatus 11 moves up and down a solder pumping port 13 having a solder exposure port 12 to pump up and solder the molten solder 15a in the solder bath 14. First, the solder drawing port 13 is submerged in the solder bath 14 to draw in the molten solder 15a (not shown). Next, when the solder pumping port 13 is taken up from the inside of the solder bath 14, the molten solder 15b pumped up from the opening surface of the upper surface of the solder exposure port 12 positioned below the opening of the upper surface of the solder pumping port 13 is indicated by an arrow. Will flow out. Soldering is performed by the flowing molten solder 15b. In this conventional example, the float 16 is inserted into the solder pumping port 13 and vibrated, so that the molten solder 15b on the opening surface of the solder exposure port 12 is vibrated. As a result, the so-called stringing is eliminated when the soldered body is separated after soldering, and the solder breakage is made appropriate.

JP 59-147772 (see FIG. 1) Japanese Patent Laid-Open No. 11-5155 (see FIGS. 2 and 3) JP-A-8-267227

  However, in the soldering apparatus described in Patent Document 1, since the check valve 9 is provided in the molten solder 10, it is necessary to satisfy the condition of excellent heat resistance and long life. The check valve 9 is made of an inelastic material such as a stainless material, a titanium material, or a ceramic material. Therefore, the contact between the valve body and the valve seat may be insufficient due to wear or adhesion of foreign matter such as sludge, which may cause leakage. If leakage occurs, the pressure in the pressure chamber 3 changes, the height of the molten solder 10 ejected from the nozzle 6 becomes unstable, and the quality deteriorates. Also in the soldering apparatus described in Patent Document 3, when a piston is used, leakage may occur between the piston and the cylinder for the same reason. When a fan is used, the molten solder 10 is caused by the pulsation of the fan. The spout height of fluctuates. Further, in any case, movable parts such as valves, pistons, fans and the like are immersed in the molten solder 10, so that they are likely to fail.

On the other hand, in the scooping-up type soldering apparatus described in Patent Document 2, it is necessary to repeatedly put in and out for scooping up the molten solder 15a every time the soldered body is soldered. Cannot be soldered continuously. For this reason, it is not suitable for mass production. Moreover, it is sent out from the solder exposure port 12 with a slight drop, and there are many cases where a sufficient discharge amount of the molten solder 15b cannot be obtained, the discharge amount cannot be controlled, and the discharge time cannot be controlled. There is a problem.
Therefore, an object of the present invention is to provide a jet soldering apparatus that has no moving parts in solder and is extremely reliable.

In order to solve the problem, the soldering apparatus of the present invention is
A sealed storage tank capable of controlling the pressure in the space in contact with the liquid level during solder storage;
A collection tank whose upper end is open to the atmosphere;
A solder return pipe (hereinafter referred to as “return pipe”) that stands in the storage tank and has an upper end that opens and a lower end that passes through the storage tank and communicates with the recovery tank;
A solder feed pipe (hereinafter referred to as “feed pipe”) standing in the collection tank and having an upper end opened and a lower end located at a position lower than the upper end of the solder return pipe and penetrating the collection tank and communicating with the storage tank. ")").

According to this configuration, when the internal pressure of the storage tank is increased in a state where the storage tank, the return pipe, the feed pipe, and the recovery tank are filled with molten solder, a part of the solder in the storage tank is transferred to the feed pipe and the solder in the return pipe A part of move to the collection tank. Then, the liquid level in the return pipe is lowered to a point where the sum of the pressure of the solder column B and the atmospheric pressure in the recovery tank at a higher level is balanced with the internal pressure of the storage tank, and the liquid level in the recovery tank is increased. . On the other hand, since the upper end portion of the feed pipe is open, the liquid overflows when the liquid level in the feed pipe reaches the open face. Therefore, as long as the internal pressure of the storage tank is maintained higher than the sum of the pressure of the solder column A and the atmospheric pressure in the feed pipe above the liquid level in the storage tank, this overflow state continues. Therefore, soldering can be performed with the molten solder in the overflow state. When the soldering is completed, the molten solder in the recovery tank returns to the storage tank from the return pipe simply by returning the storage tank to atmospheric pressure. In order to consume the filled solder as efficiently as possible, the lower end of the return pipe communicates with the recovery tank at the lowest position of the storage tank, and the lower end of the feed pipe communicates with the storage tank at the lowest position of the recovery tank. It is good to be.
The plane area of the storage tank needs to be sufficiently larger than that of the feed pipe so that the solder reaches the opening surface of the feed pipe and continues the overflow state. Further, the flat area of the recovery tank needs to be large enough not to flow out of the tank even if the solder in the storage tank overflows quickly. As the pressure medium in the storage tank, non-oxidizing gas (nitrogen gas, argon gas, helium gas, carbon dioxide gas) is preferably used to prevent oxidation of the solder, but when a pressure absorber described later is used in combination. Air may be used.

The storage tank and the recovery tank are adjacent to each other, or one of them includes the other, the wall of the storage tank through which the return pipe penetrates also serves as one wall of the recovery tank, and the wall of the recovery tank through which the feed pipe penetrates It can be set as the structure which serves as one wall of a storage tank. Thereby, space saving of a soldering apparatus can be achieved.
There may be a plurality of the feed tubes. This is because it can respond to various mass production needs such as when the size is large or when there are many places to be soldered.
Moreover, there may be a plurality of the storage tanks, a return pipe may be set up in each storage tank, and each return pipe may communicate with a single collection tank. By enabling the plurality of storage tanks to be switched between simultaneous operation or single operation, this system can be used with a single unit to cope with high volume production and low volume production, or with various sizes. This is because it is possible to cope with a case where soldered bodies are mixed.

Furthermore, the soldering apparatus according to the present invention preferably includes a fluid pressure device that is connected to the storage tank and changes the pressure in the storage tank. This is because the pressure in the storage tank can be easily controlled. In the configuration including the fluid pressure device, it is particularly preferable that the fluid pressure device is connected to a storage tank via a switching valve, and further absorbs a pressure medium flowing between the fluid pressure device and the storage tank. The pressure absorber is connected to the switching valve. Since the inside of the storage tank is sealed, the internal pressure of the storage tank fluctuates due to a temperature change even when the fluid pressure device is stopped. For example, when the soldering device is started, the solder is heated from room temperature to the melting temperature, and the pressure medium is thermally expanded to increase the internal pressure of the storage tank. It becomes difficult to properly control. Therefore, the switching valve is switched so that the inside of the storage tank communicates with the pressure absorber until the internal pressure of the storage tank reaches a steady state, and the expanded pressure medium is absorbed by the pressure absorber. Then, when the steady state is reached, the switching valve is returned and the pressure is controlled by the fluid pressure device. On the other hand, when the internal pressure of the storage tank decreases due to a decrease in ambient temperature, the pressure medium in the pressure absorber may be returned. When a pressure absorber is installed, air can be used as the pressure medium. This is because the amount of oxygen in contact with the solder is limited to the amount of oxygen in the pressure absorber, and the oxidation of the solder is suppressed. It is particularly preferred that the pressure absorber contains an oxygen scavenger. This is because the molten solder is prevented from being oxidized.
In the case where a pressure absorber is provided, the internal pressure of the storage tank can be returned to a steady state by switching the switching valve for each cycle even during continuous operation.

  As described above, the soldering apparatus of the present invention is established using the physical principle due to the pressure difference, and since the movable part that operates mechanically is not immersed in the solder, pressure leakage, There is almost no endurance deterioration or component failure, and it is extremely reliable.

Embodiment 1
1 is a partially broken perspective view of a soldering apparatus according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of the main part of the apparatus, and FIG. 3 shows a liquid level of molten solder when gas is injected. FIG. 4 is a cross-sectional view of an essential part in another method of using the apparatus, and FIG. 5 shows a solder discharge port provided at the upper end portion of the feed pipe. Cross-sectional view of the main part, (b) is a cross-sectional view of the main part when the cross-sectional area is smaller than that of the feed pipe.
As shown in FIGS. 1 and 2, the soldering device 17 includes a sealed storage tank 18 and an air-released recovery tank 19, and a wall that partitions these two tanks also serves as one side surface of each tank. Thus, two tanks are provided adjacent to each other. And the coupling | bond part 20 and the coupling | bond part 21 for a molten solder to move between the storage tank 18 and the collection tank 19 are provided in the lower part of the partition. The storage tank 18 has an upper lid 22 hermetically closed by a bolt 23, and is provided with a supply pipe 24 in order to press-fit a gas as a pressure medium from a pressurizing means (not shown). This gas is a non-oxidizing gas. One coupling portion 20 is joined to a lower end portion of a feed pipe 26 for moving the molten solder 25 in the storage tank 18 into the recovery tank 19. The feed pipe 26 is raised in the vertical direction in the recovery tank 19 and has a sufficient height so that the upper end portion is always located above the liquid level 28 of the molten solder 27 in the recovery tank 19. . The other connecting portion 21 is joined to the lower end portion of a return pipe 29 for moving the molten solder 27 in the recovery tank 19 into the storage tank 18. The return pipe 29 is raised in the vertical direction in the storage tank 18, and is designed so that the upper end portion is positioned below the liquid level 30 of the molten solder 25 at rest when the pressure medium is not always pressed into the storage tank 18. Has a height. A discharge port 31 that is larger in diameter than the feed tube 26 and opens upward is attached to the upper end portion of the feed tube 26. Further, as a heating source for the storage tank 18 and the recovery tank 19, a heater 34 is incorporated in the lower part.

When using the soldering device 17, the heater 34 is turned on to bring the solder into a molten state, and gas is injected into the storage tank 18. Then, the liquid level 30 of the molten solder 25 shown in FIG. 2 is pushed down to the position of the liquid level 35 as shown in FIG. On the other hand, in the collection tank 19, the liquid level 28 of the molten solder 27 shown in FIG. Here, the solder column corresponding to the height difference (drop) between the liquid level in the discharge port 31 and the liquid level 35 in the storage tank 18 is A, and the liquid level 36 in the recovery tank 19 and the liquid in the return pipe 29 are defined as A. The solder pillar corresponding to the height difference (head) from the position 37 is represented by B. Then, assuming that the internal pressure of the storage tank 18 is instantaneously constant, when the liquid level 35 is focused, the storage tank internal pressure P = atmospheric pressure P ₀ + A, and when the liquid level 37 is focused, P = P ₀ + B is balanced. However, the liquid level does not move up and down. Further, when the gas is continuously injected and the internal pressure of the storage tank 18 is increased, the molten solder at the discharge port 31 overflows.

Then, the solder joint 33 of the body to be soldered 32 is immersed in the molten solder overflowing from the discharge port 31 for soldering. After the soldering is completed, the gas injection is stopped and the pressure in the storage tank 18 is returned to the atmospheric pressure. Then, the molten solder 27 in the recovery tank 19 returns from the return pipe 29 into the storage tank 18 due to a pressure difference (drop) between the liquid level 36 in the recovery tank 19 and the liquid level 35 in the storage tank 18.
After the soldering is completed, the inside of the storage tank 18 may be set to a negative pressure (negative pressure), and the molten solder 27 in the recovery tank 19 may be returned to the storage tank 18 through the return pipe 29. Thereby, the solder can be returned to the storage tank 18 in a short time, and even if the amount of solder decreases due to consumption, a predetermined amount of solder can be returned to the storage tank 18 and soldering can be continued. In this case, the upper end portion of the return pipe 29 may be positioned above the liquid surface 30 of the molten solder 25 as shown in FIG. Further, the position of the supply pipe 24 formed in the storage tank 18 is not limited to the upper cover 22 of the storage tank 18 as described above. For example, although not shown, the supply pipe 24 is formed on the side wall of the storage tank 18 at a position near the upper cover 22. The structure of forming can be considered.
In any case, there is no mechanically movable part in the solder during use or during stoppage. Therefore, it is excellent in durability and the quality of the obtained product is stable.

  FIG. 5 shows various forms that the discharge port 31 can take. FIG. 5A shows that the discharge port 31 a is larger than the cross-sectional area of the feed tube 26, and FIG. 5B is smaller than the cross-sectional area of the feed tube 26. This is the case of the discharge port 31b. In this way, by making the cross-sectional area of the discharge port larger or smaller than that of the feed tube, for example, in the soldered body 32 such as a printed board on which electronic components are mounted, a plurality of solder joint portions 33 are provided at one location. If the solder joints are concentrated or the area of the solder joint is large, the discharge port 31a having a large cross-sectional area is provided, and if the solder joints 33 are dispersed or the area of the solder joint is small, the area is small. A discharge port 31b having a cross-sectional area can be provided for handling. Further, the discharge port may be made of ceramic or titanium, and the feed pipe may be made of stainless steel or surface-treated (nitrided) stainless steel. .

Embodiment 2
FIG. 6 is a partially broken perspective view of a soldering apparatus according to a second embodiment of the present invention, and FIG. 7 is a cross-sectional view of the main part of the apparatus.
As shown in FIG. 6 and FIG. 7, the soldering device 38 is replaced with a plurality of feed pipes 39 and 40 branched from the single connecting portion 20 in the collection tank 19 in place of the feed pipe 26 of the first embodiment. The discharge ports 41 and 42 are formed at the respective upper ends, and the other points are the same as in the first embodiment.
Accordingly, it is possible to cope with a case where the size of the soldered body is large or a case where there are many soldering portions.
The same effect can be obtained even when a plurality of coupling portions are formed vertically and horizontally, and each of the plurality of coupling portions is provided with a feed pipe, instead of a configuration in which one coupling portion is branched into a plurality of branches.

Embodiment 3
FIG. 8 is a perspective view of an essential part of a soldering apparatus according to the third embodiment of the present invention. The soldering apparatus of this embodiment is provided with a single or a plurality of local overflow locations at the discharge port, and can perform highly reliable soldering when the object to be soldered is a transformer, choke coil, or the like. .
8A is a perspective view of the discharge port 44 having one recess 45 as a local overflow location, FIG. 8B is a perspective view of the discharge port 46 having one hole 47, and FIG. Is a perspective view of the discharge port 48 having two concave portions 49, (d) is a perspective view of the discharge port 50 having two hole portions 51, and (e) is a discharge port having four concave portions 53. 52 is a perspective view of the discharge port 54 provided with one flange 55. FIG.
FIG. 9 shows the relationship between the concave portion as a local overflow spot and the solder joint portion of the soldered body during soldering. (A) shows the case where the solder joint portion is located outside the discharge port. Schematic diagram, (b) is a schematic diagram when the solder joint is located inside the discharge port, and (c) is a schematic diagram when all of the solder joint is located inside the discharge port.

For example, when the discharge port 44 or 48 shown in FIG. 8 (a) or (c) is used, the solder joint 33 of the body to be soldered 32 is laterally attached to the discharge port 44 or 48 as shown in FIG. 9 (a). After soldering, the productivity can be increased by, for example, a method of automatically rotating the soldered body 32. In the discharge port 54 shown in FIG. 8F, the width, length, and depth of the solder flow are kept constant, so that the variation between the soldered bodies 32 after soldering can be reduced. In addition, since the solder does not scatter to the upper part of the solder joint portion 33, the enamel of the coil conductor is prevented from peeling off.
Further, when the discharge port 52 shown in FIG. 8 (e) is used, the solder joint portion 33 of the body to be soldered 32 is immersed in the discharge port 52 and soldered as shown in FIG. 9 (c). In this way, four solders can be formed, which increases productivity.
In general, in the case of transformers, choke coils, etc., polyurethane molten resin adheres to the solder joints 33 during soldering, and the resin residue peels off and adheres to other parts, which has adverse effects such as poor insulation. Therefore, a process for removing this is required. According to this embodiment, since a concentrated overflow location can be formed in the solder joint portion 33, the polyurethane molten resin adhering to the solder joint portion can be washed away, and man-hours can be saved by omitting the resin removal step. Can be reduced.
Note that the upper surfaces of the discharge ports 46, 50, 54 may be open to the atmosphere.

Embodiment 4
The fourth embodiment of the present invention is a soldering apparatus that combines a plurality of storage tanks and a single recovery tank, and is capable of switching between a plurality of storage tanks simultaneously or independently. FIG. 10 is a cross-sectional view of the main part of the soldering apparatus according to the fourth embodiment, and FIG. 11 shows the liquid level of the molten solder when a gas is injected, (a) showing the case of simultaneous operation. FIG. 4B is a diagram showing the case of single operation.
The soldering device 56 moves the molten solder 59, 60 in the left and right storage tanks 57, 58 shown in FIG. 10 to the feed pipes 62, 63 provided in the single collection tank 61, and at the upper end. It is sent out in an overflow form from the discharge ports 64 and 65 formed. On the other hand, one return pipe 66, 67 is provided in each storage tank 57, 58, respectively.
FIG. 11A shows the state of the molten solder liquid level when the gas is injected when the left and right storage tanks 57 and 58 are operated simultaneously. By simultaneously press-fitting gas into the left and right storage tanks 57 and 58 from the supply pipe 24, the molten solder 59 in the storage tank 57 and the molten solder 60 in the storage tank 58 move to the feed pipes 62 and 63. , And discharged from the discharge ports 64 and 65 at the same time in an overflow form. This simultaneous operation corresponds to the case where the number of mass production is large or the size of the printed circuit board is large.

FIG. 11B shows the state of the molten solder liquid level when the gas is injected when either one of the left and right storage tanks 57 and 58 is operated independently. For example, gas is injected from the supply pipe 24 into the storage tank 57 on the left side, the molten solder 59 in the storage tank 57 is moved to the feed pipe 62, and is sent out in an overflow form from the discharge port 64 so that the immersion solder is supplied. To do. This isolated operation corresponds to a case where the number of mass production is small or the size of the printed circuit board is small.
In any case, since the pressure of the gas to be supplied is the same on the left and right, the supply pipe 24 can be used by branching a single pipe connected to a single fluid pressure device.
When the pressure can be varied between the left and right supply pipes, for example, as shown in FIG. 12, the magnitude of the pressure for injecting the gas from the supply pipe 24 is set to the left storage tank 57> the right storage tank 58. As a result, a large amount of molten solder 59 is sent out to the left discharge port 64 and a small amount of molten solder 60 is sent out to the right discharge port 65. As a result, for example, a printed board with a large amount of soldering and a large amount of solder is handled by the left discharge port 64, and a printed board with a small amount of soldering and a small amount of solder is handled by the right discharge port 65. To do. That is, two different types of printed circuit boards can be mass-produced simultaneously.
It should be noted that a plurality of types of soldering bodies may be soldered simultaneously by changing the shape of the discharge port on the left and right.

-Embodiment 5
In the fifth embodiment of the present invention, the storage tank is present in the collection tank. FIG. 13 is a cross-sectional view of the main part of the soldering device 76 according to the fifth embodiment, and FIG. The state of the liquid level of the molten solder is shown.
The soldering device 76 forms a storage tank 77 in a collection tank 78. A joining portion 79 and a joining portion 80 for allowing molten solder to move between the storage tank 77 and the recovery tank 78 are provided near the upper portion and bottom of the storage tank 77. The storage tank 77 has an upper lid 81 hermetically closed by a bolt 82, and a supply pipe 83 is attached to the upper lid 81 in order to press-fit gas from a pressurizing means (not shown). Yes. A feed pipe 85 passes through one coupling portion 79 while maintaining airtightness, and a lower end thereof is fixed near the bottom of the storage tank 77 and an upper end thereof is positioned above the opening surface of the collection tank 78. Yes. A return pipe 88 passes through the other coupling portion 80 while maintaining liquid tightness, and is fixed so that its upper end is positioned lower than the ceiling of the storage tank 77. Further, a discharge port 91 opened upward is formed at the upper end of the feed pipe 85. A heater 92 is incorporated in the lower part of the collection tank 78.

When gas is injected into the storage tank 77 from the supply pipe 83, the liquid level 90 in the storage tank 77 before the press-fitting is pushed down to the liquid level 93 as shown in FIG. 14 and is pushed down to the liquid level 95 in the return pipe 88. . As a result, the liquid level 87 in the recovery tank 78 is pushed up to the position of the liquid level 94, and the molten solder in the feed pipe 85 reaches the upper end opening of the discharge port 91. When the pressure difference (drop) between the opening surface of the discharge port 91 and the liquid level 93 is A, and the pressure difference (drop) between the liquid level 94 and the liquid level 95 is B, when gas pressure + A = atmospheric pressure + B, The solder in the discharge port 91 keeps the balance by grabbing the opening surface. When gas is further injected, the balance is lost and the solder overflows from the discharge port 91.
In this overflow state, the solder joints of the body to be soldered are immersed and soldered. When the soldering is completed, the gas injection is stopped and the pressure in the storage tank 77 is returned to the atmospheric pressure. Then, the molten solder 86 in the recovery tank 78 returns to the storage tank 77 through the return pipe 88 due to the pressure difference (drop).
Since the mechanically movable part is not immersed in the solder, the soldering device 76 does not require maintenance for a long period of time, and enables stable soldering while maintaining set conditions.

Embodiment 6
FIG. 15 is a partially broken perspective view of a soldering apparatus according to a sixth embodiment of the present invention. This embodiment shows a place where a fluid pressure device is connected as means for press-fitting gas into a storage tank. As the fluid pressure device, a pneumatic cylinder 100 having a gas inlet / outlet connected to a supply pipe 24 is used. The piston rod 102 of the pneumatic cylinder 101 is connected to a motor 105 via a ball screw 103 and its slider 104. Other points may be the same as those of the first embodiment.
According to this soldering apparatus 100, by driving the motor 105, the slider 104 reciprocates, and the rod 102 advances and retreats accordingly. Therefore, the amount of gas entering and exiting the storage tank via the supply pipe 24 can be accurately controlled, and as a result, the amount of solder overflowing from the discharge port can be controlled. An inert gas is preferably used as the gas.
As the motor 105, a motor whose rotation speed and rotation direction can be changed is preferable, and a servo motor, a pulse motor, a hydraulic motor, or the like is applicable. When the output reciprocates like a linear motor, the ball screw 103 and the slider 104 can be omitted and the rod 102 can be directly connected.

-Embodiment 7-
FIG. 16 is a cross-sectional view of the main part of the soldering apparatus according to the seventh embodiment of the present invention. In this embodiment, a four-way valve and a pressure absorber are further added to the configuration of the sixth embodiment. Other points are the same as in the sixth embodiment.
The pressure absorber 106 is made of an oxygen-blocking flexible plastic film, has a bag shape, and an oxygen scavenger 107 is placed therein. The pressure absorber 106, the supply pipe 24, and the pneumatic cylinder 101 are connected via a four-way valve 108.

According to this soldering apparatus 200, the amount of gas entering and exiting the storage tank via the supply pipe 24 can be accurately controlled as in the sixth embodiment. The gas may be air. However, at the time of start-up, the solder is heated from room temperature to the melting temperature, and as a result, the gas is thermally expanded and the internal pressure of the storage tank rises. Therefore, the overflow amount of the molten solder is appropriately controlled only by the pneumatic cylinder 101. It may be difficult to do. Therefore, until the solder temperature becomes constant and the internal pressure of the storage tank reaches a steady state, the four-way valve 108 is switched so that the inside of the storage tank communicates with the pressure absorber as shown in FIG. Absorbed by the absorber 106. When the steady state is reached, the four-way valve 108 is returned and the pressure is controlled by the pneumatic cylinder 101.
In addition, as the solder temperature decreases at the end, the gas contracts and the internal pressure of the storage tank decreases, so that solder may flow into the supply pipe 24. Therefore, when the solder temperature drops to some extent, the four-way valve 108 is switched again to communicate with the pressure absorber, and the gas is returned to the storage tank. At this time, since the oxygen is removed from the gas by the oxygen scavenger, the solder is not oxidized even if it comes into contact with the solder in the storage tank.

-Eighth embodiment-
18A and 18B are cross-sectional views of the main part of the soldering apparatus according to the eighth embodiment of the present invention, where FIG. 18A is a preparation stage before soldering, FIG. 18B is a soldering start stage, and FIG. 18C is soldering. The stationary stage is shown. In this embodiment, the upper end portion of the feed pipe 126 is lower than the upper end portion of the return pipe 129 unlike the previous embodiments.
In such a positional relationship, first, the inside of the storage tank 118 is set to a negative pressure (in the figure, P1, P2 and P3 indicate absolute values of certain pressures), and the solder flows back into the storage tank 118. Thus, the solder liquid level in the storage tank 118 is made sufficiently high, while the liquid level in the recovery tank 119 is made lower than the upper end portion of the feed pipe 126 (preparation stage). Thereafter, by bringing the inside of the storage tank 118 close to atmospheric pressure, the liquid level in the storage tank 118 and the return pipe 129 is lowered, and the liquid level in the collection tank 119 and the feed pipe 126 is raised, and solder is supplied from the feed pipe 126. Overflow (starting stage). Further, by increasing the internal pressure of the storage tank 118 to a positive pressure, the solder overflow state is continued (steady stage).
According to this embodiment, when the tank volume is the same, the total amount of solder in the storage tank and the recovery tank may be smaller than in the previous embodiments. Further, since the discharge port is surrounded by the inner wall of the recovery tank, there is an advantage that the solder is not scattered.

It is a partially broken perspective view of the soldering apparatus of Embodiment 1. It is principal part sectional drawing of the same apparatus. It is a figure which shows the state of the liquid level of the molten solder when gas is injected in the same apparatus. It is principal part sectional drawing which shows the usage method of the apparatus. The discharge port applied to the apparatus is shown, (a) is a cross-sectional view of the main part of the discharge port larger than the cross-sectional area of the feed pipe, (b) is a cross-sectional view of the main part of the discharge port smaller than the cross-sectional area of the feed pipe. It is. It is a partially broken perspective view of the soldering apparatus of Embodiment 2. It is principal part sectional drawing of the same apparatus. The discharge port used for the soldering apparatus of Embodiment 3 is shown, (a) is provided with one recessed part as a local overflow location, (b) is provided with one hole part, (c ) With two recesses, (d) with two holes, (e) with four recesses, (f) with one collar It is a perspective view of a thing. The relationship between a local overflow location and the solder joint part of a to-be-soldered body is shown, (a) is a schematic diagram when a solder joint part is located outside the discharge port, and (b) is inside the discharge port. FIG. 4C is a schematic diagram when the solder joint portion is positioned, and FIG. 5C is a schematic diagram when the entire solder joint portion is positioned inside the discharge port. It is principal part sectional drawing of the soldering apparatus of Embodiment 4. FIG. 2 shows the liquid level of the molten solder when a gas is injected in the apparatus, where (a) shows a simultaneous operation and (b) shows a single operation. It is a state figure of the liquid level at the time of making the pressure in the right and left storage tanks different in the same device. It is principal part sectional drawing of the soldering apparatus of Embodiment 5. FIG. It is a figure which shows the state of the liquid level of the molten solder when gas is injected in the same apparatus. It is a partially broken perspective view of the soldering apparatus of Embodiment 6. It is principal part sectional drawing of the soldering apparatus of Embodiment 7, (a) shows the state which the solder overflows from the discharge outlet, (b) shows the state which is going to finish soldering. It is principal part sectional drawing which shows the state which switched the 4-way valve in the same apparatus. FIG. 10 is a cross-sectional view of a main part of a soldering apparatus according to an eighth embodiment, where (a) shows a preparation stage before soldering, (b) shows a soldering start stage, and (c) shows a steady soldering stage. It is principal part sectional drawing of the conventional jet type soldering apparatus. It is principal part sectional drawing of the conventional pumping type soldering apparatus.

Explanation of symbols

17, 38, 56, 76, 117 Soldering device 18, 57, 58, 77, 118 Storage tank 19, 61, 78, 119 Recovery tank 20, 79 Coupling part 21, 80 Coupling part 24, 83 Supply pipe 25, 27 59, 60, 84, 86 Molten solder 26, 39, 40, 62, 63, 85, 126 Feed pipe 28, 87 Liquid level of molten solder in recovery tank 29, 66, 67, 88, 129 Return pipe 30, 90 Liquid surface of molten solder at rest of storage tank 31, 31a, 31b, 41, 42, 44, 46, 48, 50, 52, 54, 64, 65, 91 Discharge port 32, 43 To-be-soldered body 33 Solder joint Part 45, 47, 49, 51, 53, 55 Local overflow location

Claims (7)

A sealed storage tank capable of controlling the pressure in the space in contact with the liquid level during solder storage;
A collection tank whose upper end is open to the atmosphere;
A solder return pipe standing in the storage tank and having an upper end opened and a lower end penetrating the storage tank and communicating with the recovery tank;
The solder tank is provided with a solder feed pipe that is erected in the recovery tank and has an upper end that is open, a lower end that is lower than the upper end of the solder return pipe, and that communicates with the storage tank through the recovery tank. Soldering device.   The storage tank and the recovery tank are adjacent to each other, or one of them includes the other, the wall of the storage tank through which the solder return pipe penetrates also serves as one wall of the recovery tank, and the recovery tank through which the solder feed pipe penetrates. The soldering apparatus according to claim 1, wherein the wall also serves as one wall of the storage tank.   The soldering apparatus according to claim 1, wherein the solder feeding pipe is a plurality.   Soldering according to any one of claims 1 to 3, wherein there are a plurality of storage tanks, a solder return pipe is erected in each storage tank, and each solder return pipe communicates with a single recovery tank. apparatus.   Furthermore, the soldering apparatus in any one of Claims 1-4 provided with the fluid pressure apparatus connected with the said storage tank and changing the pressure in a storage tank.   The fluid pressure device is connected to a storage tank via a switching valve, and a pressure absorber that absorbs a pressure medium flowing between the fluid pressure device and the storage tank is connected to the switching valve. 5. The soldering apparatus according to 5. The soldering apparatus according to claim 6, wherein the pressure medium is an inert gas, and the pressure absorber includes an oxygen scavenger.

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