JP3141306B2 - Automatic soldering equipment - Google Patents

Abstract

PURPOSE:To sustain the high airtightness on a junction surface by a method wherein a case body is halved and then hollow elastic member sealed with a gas are arranged on the junction parts to sustain the airtightness within the automatic soldering device wherein a substrate with electronic parts is heated while being carried to be soldered in a heating chamber filled up with an inert gas. CONSTITUTION:Multiple case bodies 11 vertically halved is to be a box body wherein heating chamber 15 to be an inert gas chamber filled up with nitrogen gas for soldering step is held by hollow members 14 in the same shape as that of the junction part between the junction parts 11a and 11b so as to sustain the airtightness. At this time, the nitrogen gas at the pressure of 0.2-1kg/cm<2> is sealed in this case body. When a substrate 19 and electronic part 30 are preliminarily heated, carried to a reflow soldering chamber to be brought into contact with the nitrogen gas heated at about 250 deg.C, a creamy solder is fused to solder the electronic parts 30 onto the substrate 19. At this time, within the heating chamber 15 filled up with the nitrogen gas in low oxygen concentration, the fused solder and lead wire of the electronic parts 30 are not to be oxidized at all.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic soldering apparatus and, more particularly, to a plurality of housings in which a hollow elastic member filled with a gas such as an inert gas is provided at a joint of divided housings. By forming an inert gas chamber by joining, high airtightness can be maintained at the joint even if the processing accuracy of the joint surface is not very good, and the inert gas chamber can be easily disassembled to facilitate maintenance. The present invention relates to an automatic soldering apparatus that has greatly improved.

[0002]

2. Description of the Related Art Conventionally, in an automatic soldering apparatus, an electronic component is soldered to a substrate by melting the solder by heating the substrate and the solder in an atmosphere where a large amount of oxygen is present. According to the automatic soldering apparatus, the solder and the molten solder are oxidized due to the exposure of the solder and electronic parts to oxygen at a high temperature, so that sufficient soldering performance cannot be ensured, or troublesome solder residue removal is performed. There was a disadvantage that work had to be performed.

In particular, in recent years, as electronic components have become smaller and lead wires have become thinner, even a slight defect such as oxidation of a soldered portion has serious consequences such as a decrease in reliability of electronic products. Was causing it.

In order to solve such a drawback, an automatic soldering apparatus is filled with an inert gas such as nitrogen gas and soldered in a state where oxygen is cut off, and the electronic parts, the substrate and the solder are heated to a high temperature. Also, there has been proposed an automatic soldering apparatus for performing soldering so as not to oxidize a soldering portion or molten solder.

Since an inert gas such as nitrogen gas used in this type of automatic soldering apparatus is expensive, it is necessary to minimize the leakage of the inert gas from the automatic soldering apparatus. Various measures have been taken to increase the degree of sealing of the device.

In order to increase the degree of sealing of the automatic soldering device, it is conceivable that the housing containing the soldering device is integrally manufactured by welding or the like to form a completely sealed structure. Maintenance or repair of the built-in soldering device at the time of inspection or failure becomes extremely difficult, and is not practical.

For this reason, the housing is usually manufactured by dividing the housing into upper and lower parts, and an elastic member is sandwiched and joined between the two housings.
An apparatus that seals the joint to maintain the tightness of the automatic soldering apparatus has been put to practical use.

In this conventional example, in FIG. 5, one housing 1 in which a joining surface 1a is formed in a flat shape, and a joining surface 2a are formed.
a, a solid elastic member 3 having a rectangular cross section is mounted between the housing 2 and the other housing 2 in which an elastic member storage chamber having a rectangular cross section is formed;
The housings 1 and 2 were tightened by the bolts 4 and the nuts 5 to maintain the airtightness of the joint 6.

As another conventional example, as shown in FIGS. 6 and 7, one housing 1 in which a joining surface 1a is formed in a wedge shape, and the other in which an elastic member storage chamber having a rectangular cross section is formed in the joining surface 2a. A solid elastic member 8 having a rounded cross section is mounted between the casing 2 and the casing 2, and the casings 1 and 2 are tightened by bolts 4 and nuts 5 so that the wedge-shaped joining surface 1 a is cut into the elastic member 8. (See FIG. 7) The airtightness of the joint 6 is maintained.

On the other hand, the automatic soldering device is configured to solder while continuously transporting the substrate.
In some cases, the length is as long as 10 m or more, and it is difficult to manufacture the surface accuracy of the joining surfaces 1a and 2a of such large casings 1 and 2 very well. I will.

In FIG. 8, if the joint surfaces 1a and 2a have irregularities, even if the housings 1 and 2 are firmly tightened with the bolts 4 and the nuts 5, the entire length of the joint 6 is sealed only by the elastic members 3 and 8. It is difficult to stop and maintain the airtightness, and there is a drawback that the gap 9 is generated and expensive inert gas flows out of the gap 9 and is consumed.

The joining surfaces 1a, 1a,
Although it is technically possible to process the surface accuracy of 2a satisfactorily, it is not practically possible because of the large size of the apparatus, which requires a great deal of cost.

In addition, with the outflow of the inert gas from the gap 9, air flows into the automatic soldering apparatus from the board entrance and the inert gas density in the preheating chamber is reduced, thereby preventing oxidation. Will be reduced.

As a device for preventing the inflow of air from the carry-in port, there has been proposed a device for supplying more inert gas than flowing out from the carry-out port to increase the internal pressure in the automatic soldering apparatus. However, this apparatus requires a very large amount of inert gas and is not economical.

[0015]

SUMMARY OF THE INVENTION The present invention has been made to eliminate the above-mentioned disadvantages of the prior art, and an object of the present invention is to provide a housing which forms an inert gas chamber with two housings.
The hollow elastic member is divided into parts, and a hollow elastic member filled with gas is provided at a joint part of the housing so as to maintain the airtightness, so that the hollow elastic member closely adheres to the joint surface of the housing. Therefore, even if the surface accuracy of the joining surface is not so good, it is possible to maintain extremely high airtightness.

Another object is to maintain the airtightness by dividing the housing constituting the inert gas chamber into two parts and disposing a hollow elastic member filled with an inert gas at the joint of the housings. With such a configuration, the hollow elastic member is closely adhered to the joint surface of the housing so that extremely high airtightness can be maintained even if the surface accuracy of the joint surface is not so good. An object of the present invention is to ensure stable soldering performance without affecting the inert gas concentration in an automatic soldering device even if an inert gas leaks from the inside of the elastic member into the automatic soldering device.

Still another object of the present invention is to maintain high airtightness of the joint by simply joining the two divided housings with an appropriate tightening force.

Another object of the present invention is to dispose a locking piece and an engaging member in a housing, and engage the engaging member with the locking piece in a state where the hollow elastic member is mounted between the housings to form the hollow elastic member. By pressing and assembling the inert gas chamber, disassembly and assembly of the automatic soldering apparatus are facilitated to improve maintainability.

[0019]

[Means for Solving the Problems]

In short, the present invention (claim 1 ) provides an automatic soldering apparatus that heats and solders a board on which electronic components are mounted while transporting the board in a heating chamber filled with an inert gas. A plurality of housings constituting a gas chamber; and a hollow elastic member provided at a joint of the housings and filled with an inert gas therein, wherein the hollow elastic member is sandwiched by the housings. It is characterized by the following.

The present invention (claim 2 ) provides an automatic soldering apparatus for heating and soldering a substrate on which electronic components are mounted while being transported in a heating chamber filled with an inert gas.
A plurality of housings forming an inert gas chamber by joining, a locking piece formed on one of the plurality of housings, and a plurality of housings corresponding to the locking pieces are disposed on the other one of the housings. And a hollow elastic member disposed at a joint portion of the housing and filled with an inert gas therein, wherein the locking piece is attached to the housing in a state where the hollow elastic member is mounted between the housings. The hollow elastic member is configured to be pressed by engaging the engaging member.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings. 1 and 2, an automatic soldering apparatus 10 according to the present invention includes a plurality of vertically divided housings 11, locking pieces 12, engaging members 13, and hollow elastic members 14. .

An embodiment in which the present invention is applied to a reflow-type automatic soldering apparatus 10 as an example of an automatic soldering apparatus will be described below with reference to FIG.

[0024] First a description will be given of the basic configuration of the reflow type automatic soldering apparatus 10, housing 11 of the reflow type automatic soldering apparatus 10 includes an upper housing 11A and lower housing 11
B and manufactured separately.

The inside of the housing 11 becomes an inert gas chamber divided into two preheating chambers, a reflow soldering chamber, and a slow cooling chamber (each not shown) by a partition wall (not shown). Heating chambers 15 are formed, and the structure of each chamber is
The structure is almost the same except for the internal temperature.

A known endless chain conveyor 16 as an example of a transport device is provided in the preheating chamber, the reflow soldering chamber, and the annealing chamber so as to penetrate therethrough. 19 is sequentially conveyed to a preheating chamber, a reflow soldering chamber, and an annealing room to be soldered, and is carried out to an unloading station 20.

A casing 21 is provided in a preheating chamber, a reflow soldering chamber, and a cooling chamber which are independently formed and filled with an inert gas such as nitrogen gas. Ascending circulation passage 15U between body 11B
However, a descending circulation passage 15 </ b> D is formed in the casing 21.

Chain conveyor 16 in casing 21
A heating device 24 having a sandwich structure in which the electric heater 22 is sandwiched between metal plates 23 having a large number of holes 23a is disposed above the heaters. The heating is controlled so as to be about 150 ° C., about 250 ° C. in the reflow soldering chamber, and about 130 ° C. in the slow cooling chamber.

The substrate 1 mounted on the chain conveyor 16
9, after being preheated in the preheating chamber while being conveyed,
In the reflow soldering chamber, the solder is rapidly heated to the soldering temperature and soldered, and gradually cooled in the slow cooling chamber, and is unloaded from the unloading station 20.

The blower 25 is for forcibly circulating an inert gas such as a heated nitrogen gas which fills the heating chamber 15 and is provided below the preheating chamber, the reflow soldering chamber and the annealing chamber. A belt (not shown) is wound between a pulley 29 fixed to a shaft 28 supported by a bearing 26 such as a ball bearing by a centrifugal blower such as a sirocco fan and a pulley of a motor (not shown). And driven by the motor.

After the nitrogen gas filled in the heating chamber 15 is sucked and heated by the heating device 24, the descending circulation passage 15
D is lowered in the direction of arrow A, and after the substrate 19 conveyed by the chain conveyor 16 is heated, the substrate 19 is pressure-fed in the direction of arrow B by the blower 25 and is raised again in the direction of arrow C through the ascending circulation passage 15U to circulate. Is configured.

Then, the substrate 1 is heated by the heated nitrogen gas.
The electronic component 30 is soldered to the substrate 19 by gradually heating the electronic component 9 to a soldering temperature.

A plurality of upper and lower divided housings 11 are boxes for filling and soldering a nitrogen gas in a heating chamber 15 serving as an inert gas chamber, and have a sealed upper structure. The heating chamber 1 is composed of a housing 11A and a lower housing 11B, and the upper housing 11A and the lower housing 11B are joined together with their open ends facing each other and combined to form an inert gas chamber.
5 are formed.

The open ends of the upper housing 11A and the lower housing 11B have joining portions 11a and 11 having an L-shaped cross section, respectively.
b is welded over the entire circumference and the hollow elastic member 14
The is configured so as to sandwich at the two junction 11a and 11b.

Referring mainly to FIG. 3, the locking piece 12 is for joining the upper casing 11A to the lower casing 11B, and has a plurality of projections 11c, which are connected to the joining section 11a of the upper casing 11A. It is formed continuously.

The engaging members 13 are for joining the upper housing 11A to the lower housing 11B in cooperation with the locking pieces 12, and are provided at positions corresponding to the locking pieces 12, respectively. A support base 31 is fixed to a joint portion 11b of the lower housing 11B with a bolt 32 and a nut 33.

A connecting link 35 is rotatably connected between the support base 31 and a hook-shaped engaging arm 34 by shafts 36 and 38, and a hook portion 34a of the engaging arm 34 is provided. The upper housing 11A and the lower frame 11B are joined together by engaging the locking piece 12 with the locking piece 12 and rotating the locking piece 12 in the direction of arrow D.

The hollow elastic member 14 has the joints 11a, 11
b, is a hollow silicon rubber tube with high airtightness manufactured to have the same shape as that of the joint 11a and for maintaining the airtightness of the joint. Through a pipe 40, and nitrogen gas at a pressure of 0.2 to 1 kg / cm ² is supplied from the nitrogen gas supply device 39 in the direction of arrow F and sealed.

A pressure gauge 41 is mounted on the pipe 40, and measures the pressure of the nitrogen gas sealed in the hollow elastic member 14.

The present invention is configured as described above,
Hereinafter, the operation will be described. 1 and 2, first, when the substrate 19 is mounted on the chain conveyor 16 at the loading station 18, the substrate 19 is transported by the chain conveyor 16, and the nitrogen gas is supplied for about 190 minutes.
A relatively small electronic component having a small heat capacity, which is rapidly heated in a preheating chamber heated to about 190 ° C., is immediately heated to about 190 ° C., the same as the temperature of nitrogen gas, but has a relatively large heat capacity. The electronic component has a surface portion of about 190
In contrast to heating to ℃, the inside is not sufficiently heated and has a lower temperature.

Then, it is transported to the next preheating chamber heated to about 150 ° C., and the electronic components having a small heat capacity are lowered in temperature, and the electronic components having a large heat capacity are further gradually heated to adjust the whole temperature. Then, all the components of the substrate 19 and the electronic component 30 reach a uniform temperature of about 150 ° C., and the preheating is completed.

The nitrogen gas contacting the substrate 19 from above is
The flow branches off in the left-right direction, and the flow direction is
Is determined by the positional relationship between the substrate 19 and the blower 25, and the position of the substrate 19 being transported is constantly changing, so that the flow direction also changes from right to left and from left to right. In the preheating chamber, the nitrogen gas flows in the direction of flowing out to the loading station 18 or in the direction of the next preheating chamber opposite to the direction of the loading station 18.

The nitrogen gas that has passed through the chain conveyor 16 and has further descended in the direction of arrow A is sucked by the blower 25 and flows right and left in the direction of arrow B to rise in the ascending circulation passage 15.
It rises in U and returns above the heating device 24.

At this time, the temperature of the nitrogen gas is detected by a temperature sensor (not shown) and transmitted to a control device (not shown), and the power supplied to the heating device 24 is adjusted according to a command from the control device. The nitrogen gas in the chamber 15 is controlled to have a predetermined temperature.

Next, the substrate 19 is transported to the reflow soldering chamber, where it is heated by contact with nitrogen gas heated to about 250 ° C. in the same manner as in the preheating chamber, so that the cream solder melts and The component 30 is soldered to a predetermined location on the board 19.

In the preheating chamber and the reflow soldering chamber,
Since the nitrogen gas, which has a very low oxygen concentration of about 500 ppm, is filled, the molten solder and electronic components 3
The zero lead wire is not oxidized, and ideal soldering is performed.

The substrate 19 that has been soldered in the reflow soldering chamber and still in a high temperature state is transported to a slow cooling chamber at about 130 ° C. and cooled slowly, and then transported to the unloading station 20. It is carried out.

Although the electronic component 30 is soldered to the substrate 19 as described above, the soldering performance is greatly affected by the oxygen concentration in the heating chamber 15 and how to keep the inside of the heating chamber 15 inert. Is important.

Referring also to FIG. 4, hollow elastic member (for example, a silicone rubber tube) 14 is provided with joints 11a and 11b.
The hollow elastic member 14 is disposed between them and is filled with nitrogen gas at a pressure of 0.2 to 1 kg / cm ^{2 in} the direction of arrow F, so that the hollow elastic member 14 has the shape of the joints 11a and 11b. Along with the space between the upper housing 11A and the lower housing 11B, thereby completely sealing the space between the upper housing 11A and the lower housing 11B.

The nitrogen gas sealed from the inside of the hollow elastic member 14 leaks little by little through the hollow elastic member 14 in the direction of the arrow E. The nitrogen gas is the same as the gas filling the heating chamber 15. Since it is an inert gas, it does not affect soldering performance.

[0051]

In the above embodiment, the present invention is described as being applied to a reflow-type automatic soldering apparatus. However, the application of the present invention is not limited to the reflow-type automatic soldering apparatus, but is applied to a jet-type automatic soldering apparatus. Of course, the present invention can also be applied to a dip-type automatic soldering apparatus.

[0053]

According to the present invention, the housing constituting the inert gas chamber is divided into two parts as described above, and a hollow elastic member filled with gas is disposed at the joint of the housings to provide airtightness. Is held, the hollow elastic member is closely adhered to the joint surface of the housing, and there is an effect that extremely high airtightness can be maintained even if the surface accuracy of the joint surface is not so good.

The housing constituting the inert gas chamber is divided into two parts, and a hollow elastic member filled with an inert gas is disposed at the joint of the housing to maintain airtightness. Therefore, there is an effect that the hollow elastic member is closely adhered to the joint surface of the housing to maintain extremely high airtightness even if the surface accuracy of the joint surface is not so good. Even if it leaks into the automatic soldering device, stable soldering performance can always be ensured without affecting the inert gas concentration in the device.

Further, with the above configuration, there is an effect that high airtightness of the joined portion can be maintained only by joining the two divided housings with an appropriate tightening force.

Further, a locking piece and an engaging member are provided in the housing,
With the hollow elastic member mounted between the housings, the engaging member is engaged with the locking piece and the hollow elastic member is pressed to assemble the inert gas chamber. This facilitates maintenance and has the effect of improving maintainability.

[Brief description of the drawings]

FIGS. 1 to 4 relate to an embodiment of the present invention, and FIG. 1 is an exploded perspective view of a housing and a hollow elastic member of an automatic soldering apparatus.

FIG. 2 is a longitudinal sectional view of a heating chamber of the automatic soldering apparatus.

FIG. 3 is an enlarged vertical cross-sectional view of a main part showing an operation of a hollow elastic member mounted between housings.

FIG. 4 is a vertical sectional view taken along the line IV-IV in FIG. 3;

5 to 8 relate to a conventional example, and FIG. 5 is an enlarged longitudinal sectional view of a solid elastic member mounted between housings.

FIG. 6 is an enlarged longitudinal sectional view of a solid instep-shaped elastic member mounted between the housings.

FIG. 7 is an enlarged vertical cross-sectional view showing a state in which one housing is cut into and joined to a solid instep-shaped elastic member.

8 is a vertical sectional view taken along the line VIII-VIII in FIGS. 5 to 7. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Automatic soldering apparatus 11 Plural housings 11A Upper housing 11B as an example of one housing Lower housing 11a as an example of the other housing 11a Joining portion 11b Joining portion 12 Locking piece 13 Engaging member 14 Hollow elastic member 15 Heating chamber 19 substrate 30 electronic component

Claims (2)

(57) [Claims] 1. An automatic soldering apparatus for heating and soldering a substrate on which electronic components are mounted while transporting the substrate in a heating chamber filled with an inert gas, wherein a plurality of housings forming an inert gas chamber by joining are provided. An automatic soldering apparatus, comprising: a hollow elastic member provided at a joint of the housing and filled with an inert gas therein, wherein the hollow elastic member is sandwiched by the housing. . 2. An automatic soldering apparatus for heating and soldering a substrate on which electronic components are mounted while transporting the substrate in a heating chamber filled with an inert gas, wherein a plurality of housings forming an inert gas chamber by joining are provided. A locking piece formed on one of the plurality of housings, an engagement member provided on the other of the housings corresponding to the locking pieces, and a joining portion of the housings. And a hollow elastic member in which an inert gas is sealed inside, and the engaging member is engaged with the locking piece in a state where the hollow elastic member is mounted between the housings to press the hollow elastic member. An automatic soldering apparatus characterized in that it is configured to perform