JPH05146868A - Nitrogen-seal injecting type soldering device - Google Patents

Abstract

PURPOSE:To provide a nitrogen-seal injecting type soldering device, in which the necessary nitrogen atmosphere in the soldering process part can surely be produced in the above soldering device having carrier-less conveying mechanism as variable in carrying angle and carrying width and executing at least the soldering process with the necessary nitrogen atmosphere. CONSTITUTION:In the injecting type soldering device constituted by providing a carrying conveyor 2 (tracks 2a, 2b) constituted as variable in the carrying angle and the carrying width and having a soldering vessel 8' at the lower part, in order to form a space S1 for storing the nitrogen gas at the upper part of the soldering vessel 8', an upper closing plate 50 is arranged as approaching to the upper surface of the tracks 2a, 2b at the upper part of both tracks 2a, 2b. Further, side sealed plates 55A, 55B projecting downward to the soldering vessel 8' and dipped in the molten soldering vessel 8' at the lower end are arranged at the lower surfaces of both tracks 2a, 2b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitrogen-encapsulated jet type soldering apparatus, and more particularly, to a high nitrogen atmosphere in a solder bath while having carrierless conveying means whose conveying angle and conveying width are both variable. The present invention relates to a nitrogen-filled jet-type soldering device that can be created.

[0002]

2. Description of the Related Art Conventionally, a printed circuit board is generally soldered by a jet type (automatic) soldering device. FIG. 7 shows an example of a jet type soldering device.
In this soldering apparatus 1, reference numeral 2 is a conveyer conveyor for conveying an article to be soldered (for example, a printed circuit board) to be soldered. The transfer conveyor 2 is composed of two tracks 2a and 2b provided in parallel and facing each other. Soldered products are those tracks 2
It is conveyed in a state of being installed between a and 2b. Below the transfer conveyor 2, along the extending direction of the transfer conveyor 2 from the inlet side (front side in the drawing) toward the outlet side, the fluxer 5, the warm air heater 6, the preheater 7, the solder bath 8, The cooling fan 9 and the like are sequentially arranged.

With this configuration, the printed circuit board carried into the soldering device 1 from the entrance side of the conveyor 2 is first coated with flux by the fluxer 5 and then applied to the warm air heater 6. The flux is dried, preheated by the preheater 7, soldered in the solder bath 8, cooled by the cooling fan 9 and then carried out and moved to the next step. Will be things.

Here, the conveyor 2 is inclined so as to be slightly upward from the entrance side toward the exit side.
This is for more reliable soldering in the solder bath 8. The transport conveyor 2 is supported by a frame (not shown) arranged outside the tracks 2a and 2b, and the tilt angle of the frame is variable together with the frame. Further, the transfer conveyor 2 has both tracks 2a corresponding to the width of the printed circuit board to be transferred,
The distance between the two 2b can be adjusted.

By the way, in the soldering apparatus (process) as described above, conventionally, a flux containing pine resin (rosin) or a halide is used as the flux adhered by the fluxer 5. If this flux remains on the printed circuit board, it may cause corrosion or decrease in insulation resistance. Therefore, cleaning with chlorofluorocarbon or trichloroethane was performed after the soldering process. However, in recent years, it has been determined that these fluorocarbons and trichloroethane are internationally regulated as ozone-depleting substances.

Under these circumstances, recently, a soldering apparatus which does not require cleaning of flux in the soldering process of a printed circuit board has begun to be provided. It was developed from the following viewpoints. In other words, the flux is a so-called reducing agent (antioxidant), and the stronger the action, the better the original function of the flux is. However, such flux has a large amount of residue, which requires cleaning after soldering. .. That is, the above soldering apparatus volatilizes the flux in the soldering process by using a flux having a small reducing action, and does not require cleaning of the flux. When such a flux is used, it is feared that the terminals and copper foil will be oxidized before reaching the soldering part. Therefore, soldering should be performed in an inert gas (nitrogen gas) atmosphere. There is.

For example, ELECTRONIC PACKING & PRODUCTIO
In N magazine, April 1990 issue, P64-P66, in the jet type soldering device, the entire transport system from the fluxer to the cooling device is covered with a cover in a tunnel shape, and nitrogen gas is supplied to almost the entire area inside the cover. A nitrogen-enclosed jet-type soldering device in which a mouth is arranged and the entire inside of the cover is made into a nitrogen atmosphere is disclosed. In this case, the oxygen concentration inside the cover that covers the entire transport system is set to about 50 ppm or less. According to the nitrogen-filled type soldering apparatus as described above, good soldering can be performed even if a flux having a small reducing action is used.

[0008]

However, the above-mentioned nitrogen-encapsulated jet type soldering device has the following disadvantages. That is, in the above apparatus, the transport mechanism for transporting the printed circuit board is of the carrier type (pallet transport type). Therefore, the conveying path is formed in a so-called belt conveyor, and the printed boards are mounted one by one on a dedicated pallet and conveyed on the conveyor belt. Further, the transport path is considered to be in consideration of the flow in the cover, but is formed in a slanted shape such that it repeats up and down with respect to its extending direction. Due to such a structure, the above-mentioned nitrogen-enclosed jet-type soldering device is shown in FIG.
It cannot be applied to the carrierless type as shown in (1), that is, the soldering device in which the printed circuit board is directly held by the conveyor 2 and conveyed, and the inclination angle of the conveyor 2 is changed.

Further, the inventors of the present invention have now coped with a solder tank for carrying out soldering in the nitrogen-filled jet-type soldering apparatus as described above, without making the entire conveying system corresponding to each process into a nitrogen atmosphere. It was found that the soldering can be performed satisfactorily even when the exposed portion is in a nitrogen atmosphere.

The present invention has been made in view of the above circumstances, and has a carrierless transfer mechanism in which the transfer angle is variable, and in particular, nitrogen filling in which the soldering step is performed in a required nitrogen atmosphere. An object of the present invention is to provide a nitrogen-enclosed jet-type soldering device capable of reliably creating a nitrogen atmosphere in a soldering process part in the jet-type soldering device.

[0011]

The invention according to claim 1 is
It has a pair of parallel tracks whose distances from each other can be adjusted, and a solder tank is placed below a conveyor that conveys the products to be soldered, so that at least the soldering process is performed in a nitrogen atmosphere. A nitrogen-encapsulated jet-type soldering device comprising a shield for forming a shielded space including the transfer conveyor above the solder tank, wherein the shield is at least both tracks above the pair of tracks. An upper closing plate that covers the space and a length that substantially corresponds to the solder bath, and a side shield plate that is attached to each of the tracks and projects downward toward the solder bath. The blocking plate is close to the upper surface of each track at least in the fixed position or the moving range of each track, while at least the lower end of the side shield plate is at the lower end. And it is characterized in that it is immersed in the molten solder in the tank.

According to a second aspect of the present invention, in the nitrogen-encapsulated jet type soldering apparatus according to the first aspect, above the upper closing plate, on both sides of the conveyor in parallel with the conveyor. An upper cover is provided between the provided frames, and a lower cover that closes at least a gap between the frames and the solder bath is provided below the frames. To do.

According to a third aspect of the present invention, in the nitrogen-encapsulated jet type soldering device according to the second aspect, the lower cover has an opening through which the solder bath is viewed, and the opening cover is provided with the opening. A projecting plate extending downward toward the solder bath is formed, and at least the lower end of the projecting plate is immersed in the molten solder in the solder bath.

[0014]

In the nitrogen-filled jet type soldering device according to the first aspect of the invention, an extremely narrow enclosed space is formed between the tracks forming the conveyor. In addition, the side shield plate forming the surrounding space is soaked in the molten solder in the solder bath so that the molten solder itself acts as a structure of the surrounding space.

In the nitrogen-filled jet type soldering device according to the second aspect, the surrounding space is further doubly surrounded by the upper cover and the lower cover. At this time, the frame itself also has a structure that constitutes an outer shielded space.

In the nitrogen-filled jet-type soldering device according to the third aspect of the present invention, a structure using molten solder is constructed for the shielding between the lower cover and the solder bath.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show the vicinity of a solder bath of a nitrogen-filled jet-type soldering apparatus 60 according to the present invention. In these drawings, reference numeral 2 is a conveyer conveyor, and 8'is a solder bath. In the present embodiment, the solder bath 8'is formed into two baths by a partition plate 13 as shown in FIG. 2, and one tank is provided with a first nozzle 11 and the other bath is provided with a first nozzle 11. Two nozzles 12 are provided. Nitrogen supply pipes 14, 14, ... For ejecting nitrogen gas are provided in the vicinity of the upper end of the solder bath 8'and below the transfer line L of the printed circuit board. Nitrogen gas generated by a nitrogen generator (not shown) is introduced into these nitrogen supply pipes 14.

Below the transport conveyor 2, in addition to the solder bath 8 ', a fluxer, preheater, etc. (not shown) similar to the soldering device 1 shown in FIG. 7 are provided on the front side of the solder bath 8'. A cooling fan is arranged on the rear side of the solder bath 8 '. However, the flux used in the nitrogen-filled jet type soldering device 60 according to the present invention is a special flux having a small reducing action, and does not require cleaning after soldering. Further, the fluxer for applying the flux to the soldering surface of the printed circuit board is of a type in which the flux is sprayed and sprayed. In FIG. 1, reference numeral 3 is a transfer claw that moves along each of the tracks 2a and 2b that form the transfer conveyor 2, and as shown in the figure, the printed board P is directly gripped and transferred between the transfer claws 3 facing each other. To do.

A track 2a constituting the transfer conveyor 2,
As shown in FIG. 1, the trajectories 2a, 2a,
2b, or the frames 10 for suspending and supporting the devices such as the fluxer and the pre-heater are the tracks 2a and 2 respectively.
It extends in parallel with the tracks 2a and 2b at substantially the same height as b. That is, the change of the transfer angle of the transfer conveyor 2 is performed by changing the angles of the frames 10, 10.

The distance between the tracks 2a and 2b forming the conveyor 2 can be adjusted by a track width adjusting mechanism (not shown) so as to accommodate printed boards P of different sizes. ..

As shown in FIG. 1, an upper closing plate 50 extending over at least the two tracks 2a and 2b is provided above the pair of tracks 2a and 2b in a range substantially corresponding to the solder bath 8 '. ing. As shown in FIG. 2, the upper blocking plate 50 has a dimension slightly longer in the front-back direction than the dimension of the solder bath 8'in the same direction with respect to the extending direction of the tracks 2a and 2b. The upper closing plate 50 is made of, for example, a stainless plate. In the present embodiment, the upper closing plate 50 is supported at its both ends by frames 10, 10 arranged outside the two tracks 2a, 2b as shown in FIG. Further, the upper part of each of the tracks 2a and 2b and the portion between the tracks 2a and 2b in the upper blocking plate 50 are close to the upper surfaces of the tracks 2a and 2b as shown in FIG. This is to minimize the gap between the upper blocking plate 50 and the tracks 2a and 2b.

On the other hand, side shield plates 55A and 55B projecting downward toward the solder bath 8'are provided in the lower surfaces of the tracks 2a and 2b corresponding to the solder bath 8 '. There is. These side shield plates 55A and 55B are L-shaped when viewed from the front as shown in FIG. 1, and the short sides of the L-shape are attached to the lower surfaces of the tracks 2a and 2b with screws (not shown) or the like. There is. This side shielding plate 55A, 55B
As shown in FIG. 2, the track 2a, 2b is formed to be slightly shorter than the entire length of the solder bath 8'with its lower portion inside the solder bath 8 ', that is, in the molten solder. It is immersed.

The first and second nozzles 11 and 12 are provided inside the solder bath 8 '. Therefore, the one side shield plate 55B attached to the track 2b that can be laterally moved by the track width adjusting mechanism should avoid interference with the nozzles 11 and 12 as shown in FIG. Notch portions 56 and 57 are formed. In FIG. 2, another notch provided between these notch portions 56 and 57 is a groove 58 for allowing the partition plate 13 to escape. The cutout portions 56, 57
As a result, the side shield plate 55B can move in parallel with the other side shield plate 55A in the solder bath 8'as the track 2b moves laterally. However, both of the notches 56 and 57 are set so that the gap between the nozzles 11 and 12 does not become too large, particularly in the portions corresponding to the ejection ports 11a and 12a of the nozzles 11 and 12. That is, the gap is set to such a degree that the gap is closed by the jet of solder from the nozzles 11 and 12.

On the other hand, since the side shield plate 55A provided on the fixed track 2a is located outside the nozzles 11 and 12, the groove 58 is formed, but the notch 56, It does not have a notch such as 57.

The above-described upper blocking plate 50 and the side shield plates 55A and 55B constitute a main part of the shield body according to the present invention. As shown in FIG. 5, the upper cover 15 is provided above the upper closing plate 50, and the lower cover 16 is provided below the portion of the frames 10, 10 corresponding to the solder bath 8 '. Below, these upper covers 15
The structure of the lower cover 16 will be described.

As shown in FIGS. 1 and 2, the upper cover 15 has a rectangular top plate 17 and four side plates 18a, 18b, 18c and 18d bent vertically downward from the four sides of the top plate 17.
It is formed from and. Of the side plates 18a to 18d, the two side plates 18a and 18c facing each other are the conveyor 2
In the direction orthogonal to the extending direction of the (frame 10),
The other two side plates 18b and 18d facing each other face in the directions along the frames 10 and 10, respectively. The upper cover 15 is attached by fixing the side plates 18b and 18d to the outer surface 10a of the frame 10 with screws, for example.

The lower cover 16 has a bottom plate 23 having a size corresponding to the solder bath 8'and covering at least the entire upper opening of the solder bath 8 '. This lower cover 16
Is formed by bending a stainless plate. The bottom plate 2
Both side ends of the sheet 3 (end portions in the left-right direction of the paper surface in FIG. 1) rise upward, and the rising ends are bent horizontally outward to form a mounting portion 24. The mounting portion 24 corresponds to the frames 10 and 10 and has lower surfaces 10b and 10b.
It is attached to, for example, a screw.

The portion of the bottom plate 23 corresponding to the solder bath 8'has a rectangular opening 25 as shown in FIG.
The upper surface of the solder bath 8'can be seen from the opening 25. This bottom plate 23, as shown in FIG.
The outlets 11a and 12a are located below the outlets 11a and 12a.
Is at a position slightly above the opening 25. However, the bottom plate 23 is located above the upper end of the outer wall of the solder bath 8 '. Based on this configuration, the side shield plate 5
5A and 55B are immersed in the solder bath 8'through the opening 25.

Shield plates (protruding plates) 26a, 26b, 26c, 26d project downward from the four sides of the opening 25, as shown in FIGS. 1 and 2, respectively. Has been done. These shield plates 26a-
Since 26d is originally located in the opening 25, it is integral with the bottom plate 23 and is made of a stainless plate. The lower parts of these shield plates 26a to 26d are inside the solder bath 8 ', like the side shield plates 55A and 55B.
That is, it is inserted in the molten solder. However, these shield plates 26a to 26d are provided in a position close to the inner wall surface side plate of the solder bath 8'in a non-contact state with respect to the inner wall surface, and are located sufficiently outside of the nozzles 11 and 12. ing. Of the shield plates 26a to 26d, a pair of shield plates 2 provided in the extending direction of the conveyor 2.
Since 6b and 26d cross the partition plate 13 of the solder bath 8 ', a portion corresponding to the partition plate 13 has a form in which the partition plate 13 is escaped by a groove 27 as shown in FIG.

Further, in the present embodiment, among the side plates 18a to 18d of the upper cover 15, the side plates 18a, 18 which are formed in the front and rear direction in the direction orthogonal to the frame 10.
As shown in FIG. 5, the shutter 30 (30
A, 30B) are provided respectively. The shutter 30 closes the space between the upper cover 15 and the lower cover 16 at positions corresponding to the front and rear side plates 18a and 18c.

In this case, the shutter 30 is composed of a plurality of screens 31, 31, ... Arranged in the width direction as shown in FIG. These screens 31 have guide rails 32 whose upper ends are provided near the inner upper ends of the side plates 18a and 18c in parallel with the side plates 18a and 18c.
It engages with a groove 33 formed between 32 and can slide along the guide rail 32. Further, as shown in FIG. 6, the screens 31 are adjacent to each other and wrap in the width direction. These screens 31 are made of, for example, a film-like material having extremely high flexibility. In addition, in this case, each screen 31 has an upper bent portion 3 hooked on a guide rail 32 as shown in FIG.
4, the lower surface of the other end 34b of the screen 31 adjacent to the screen 31 is hooked on the upper surface of the one end 34a of the adjacent screens 3.
1 Prevents gaps between the two.

Now, the shutter 30 (30A, 30
B) is, as shown in FIG. 5, between the two orbits 2a and 2b, and between one of the orbits 2b, which is movable in the lateral direction in order to adjust the distance between the orbits 2a, and the frame 10 parallel thereto. It is provided for each. Of the screens 31 constituting the shutters 30A and 30B, the screen 31a adjacent to the track 2a has the same track 2a.
In addition, the screens 31b, 31 adjacent to the track 2b
c is connected to the same track 2b, and the screen 31d adjacent to the frame 10 is connected to the frame 10.

As described above, in this embodiment, the upper blocking plate 50, the side shielding plates 55A and 55B, the upper cover 15, the lower cover 16 and the shutter 30 constitute the shielding body 61 according to the present invention. ..

Next, the operation of the nitrogen-filled jet type soldering device (hereinafter abbreviated as "soldering device") 60 having the above-mentioned structure will be described. In the soldering device 60, both tracks 2 in the space above the solder bath 8 '
As shown in Fig. 1, a space between a and 2b is [both orbits 2a and 2b.
b]-[upper blocking plate 50]-[side shielding plates 55A, 55]
B]-[Solder bath 8 '(correctly, the upper surface of the molten solder inside the solder bath 8')] forms a tunnel-shaped space.

That is, an upper closing plate 50 is provided above the tracks 2a and 2b, and the upper closing plate 50 is set so that the gap between the upper surfaces of the tracks 2a and 2b is as small as possible. Therefore, the upper portion between the two tracks 2a and 2b is almost closed by the upper closing plate 50. Also, since the side shield plates 55A and 55B are respectively hung from the lower surfaces of the two orbits 2a and 2b, and the lower portions thereof are immersed in the molten solder in the solder bath 8 ', there is a gap between the two orbits 2a and 2b. The lower space is those side shield plates 55A,
It is blocked by 55B and the liquid surface of the molten solder. Here, the side shield plate 55B provided on the movable track 2b
As described above, since the notches 56 and 57 that prevent interference with the nozzles 11 and 12 are provided, there is a gap between the notches 56 and 57 and the nozzles 11 and 12. However, this gap is closed by the molten solder spouted from the nozzles 11 and 12 flowing into it.

The tunnel-shaped surrounding space is maintained in the closed state even when one of the tracks 2b is moved to change the width of the conveyor 2. That is, when the track width adjusting mechanism (not shown) is operated, the track 2b moves laterally. The side shield plate 55B is provided on the lower surface of the track 2b.
However, since the side shield plate 55B has a shape in which the portions corresponding to the nozzles 11 and 12 are escaped by the notches 56 and 57 as described above, the track 2 is provided.
The lateral movement of b is not restricted at all. Also, the cutout 5
Even if the side shield plate 55B moves in such a manner, the nozzles 1 and 5 are made by the solder jetted as described above.
The gap between 1 and 12 is closed. In addition, the upper closing plate 5
In this case, the gap between 0 and the upper surface of the moving track 2b is
Since the distance between a and 2b is constant, even if the track 2b moves laterally, the gap between the track 2b and the upper blocking plate 50 is maintained at a minute size.

Further, in the present embodiment, by the upper cover 15 and the lower cover 16, as shown in FIG. 1, [upper cover 15]-[both frames 10, 10]-[lower cover 16]-[lower cover]. 16 shield plates 26a to 26
d]-[Solder bath 8 '(upper surface of molten solder in the solder bath 8')], a tunnel-like space, that is, another tunnel-like space surrounding the space formed between both tracks 2a and 2b. A space is formed.

The openings in the front and rear of the double-structured tunnel-shaped space are formed by the shutter 30 (30A,
Since it is closed by 30B), the shielded spaces S1 and S are almost completely surrounded above the solder bath 8 '.
2 is doubled in this case.

When the one track 2b is moved in the lateral direction, for example, the direction in which the distance between the two tracks 2a and 2b is reduced, the shutters 30A and 30B are composed of a plurality of screens 31 that wrap each other. Therefore, while maintaining the desired closed state, the trajectory 2b
It is possible to change the width when moving.

In the operating state of the soldering device 60, nitrogen gas is jetted from the nitrogen supply pipes 14, 14, ... (FIG. 2). Since these nitrogen supply pipes 14 are provided in the vicinity of the upper end of the solder bath 8'as described above, the spouted nitrogen gas is formed between the orbits 2a and 2b and below the upper closing plate 50. The shielding space S1 is filled. This shielded space S1 is an extremely narrow space.
Therefore, a nitrogen atmosphere having an oxygen concentration of 5% or less can be easily created inside the shielded space S1 even when a nitrogen generator utilizing membrane separation (for example, not a nitrogen cylinder) is used as the nitrogen generating means as in the present embodiment. Be issued. In the present specification, the “nitrogen atmosphere” means a nitrogen gas concentration of 10
It does not mean 0%, which means that the proportion of nitrogen is higher and the proportion of oxygen is lower than that of normal air.

The printed circuit boards P to be soldered are sequentially transported by the transport conveyor 2, and first, a flux having a low reducing action is applied to the soldering surface (back surface) by a spray type fluxer (not shown), and then on the preheater. It passes through and approaches the solder bath 8 ′ and reaches the shield 61. The entrance of the shield 61 is the shutter 30 (3
Although the screen 31 constituting the shutter 30 is made of an extremely flexible film, the printed circuit board P (mounting board on which electronic parts are mounted) easily pushes the screen 31 away and passes through. can do. The lower ends of the screens 31 are turned up when the electronic components mounted on the printed circuit board P pass through. However, after the components pass, the screens 31 are immediately restored due to elasticity, so that the time between the screens 31 is very short. .. Therefore, the amount of nitrogen gas that leaks from the inside of the shield 16 to the outside through the shutter 30A even when the parts pass through is extremely small.

The printed circuit board which has passed through the shutter 30 (30A) and entered the shield 61 is soldered in a high-concentration nitrogen atmosphere. As a result, it is possible to effectively prevent oxidation of terminals, copper foil, and the like on the printed circuit board P, enable the use of a flux having a low reducing action, and eliminate the flux cleaning step.

The printed circuit board P soldered by passing over the solder bath 8'passes through the shutter 30A on the outlet side as in the case of the shutter 30A on the inlet side and goes out to the outside of the front shield 61 and is subjected to the next step. Is processed.

The soldering device 6 in this embodiment is also used.
At 0, since the shield 61 is provided with the upper cover 15 and the lower cover 16 in addition to the upper blocking plate 50 and the side blocking plates 55A and 55B, the gap between the tracks 2a and 2b and the upper blocking plate 50. Even if nitrogen gas leaks from the above, the leaking nitrogen gas is trapped in the shielded space S2 outside them.
For this reason, the shielding space S2 also becomes a nitrogen atmosphere having a low oxygen concentration, though not as much as the inner shielding space S1, and contributes to maintaining the nitrogen gas concentration in the inner shielding space S1 at a high level.

It has already been described that the width of the conveyor 2 can be freely adjusted in the soldering device 60. Further, the soldering device 60 is used in the transport conveyor 2
The angle adjustment can be performed in exactly the same manner as in the conventional jet type soldering device of this type.

That is, the shield 61 is also vertically moved integrally with the conveyor 2 by adjusting the angle of the conveyor 2, but in this case, there is no problem with the upper closing plate 50 and the upper cover 15. right. on the other hand,
Relative movement occurs between the side shield plates 55A, 55B and the lower cover 16 and the solder bath 8 '. However, although the side shield plates 55A and 55B are immersed in the molten solder in the solder bath 8 ', they are not restrained at all with the solder bath 8'and thus can move up and down. However, when only the conveyor 2 is moved up and down without changing the height of the solder bath 8 ', the side shield plate 55B is used.
And the nozzles 11 and 12 are in contact with each other.
57, the distance between the nozzles 11 and 12 will be greatly separated, but in reality, when the angle of the conveyor 2 is adjusted, the height of the solder bath 8'is also adjusted. It never happens. Then, as long as at least the lower ends of the side shield plates 55A and 55B are immersed in the molten solder, the substantially sealed structure of the shield space S1 is maintained. The same applies to the lower cover 16. The shield plates 16a, 16b, 16 of the lower cover 16B
Although c and 16d are immersed in the molten solder in the solder bath 8 ', they can move up and down without interfering with the solder bath 8'. As long as at least the lower ends of the shield plates 26a to 26d are immersed in the molten solder, the sealed structure of the solder bath 8'and the lower cover 16 is maintained.

Further, since the solder bath 8'is usually placed on a carriage equipped with an up-and-down mechanism in the jet type soldering apparatus, the solder bath 8'is located below the transport conveyor 2 at the time of maintenance, for example. In the case where the solder tank 8'is pulled out laterally from the device, the shield plates 16a to 16d are detached from the inside of the solder tank 8'by lowering the solder tank 8'downwardly by the vertical movement mechanism of the carriage, whereby the solder tank 8'is removed. It can be pulled out to the side.

As described above, according to the nitrogen-filled jet type soldering device 60, the solder is used in the nitrogen-filled jet type soldering device which is a carrierless type and which is provided with a carrying mechanism of varying the carrying angle and the carrying width. It is possible to reliably form the shielded space S1 that creates the required nitrogen atmosphere in the upper space of the solder bath in which the attaching process is performed. Moreover, the shielded space S1 has both tracks 2a of the transport conveyor 2,
Since it is an extremely narrow space between 2b, it is possible to easily create a nitrogen atmosphere having an extremely high nitrogen concentration.

Further, in particular, in creating the shielded space S1, a part of the shielded space is melted by the molten solder by immersing the lower portions of the side shield plates 55A and 55B in the molten solder in the solder bath 8 '. As a result, the connection with the solder bath 8'for forming the shielded space S1 can be simplified, and the conveyor 2
The angle adjustment and width adjustment can be performed without any restrictions.

Further, in the shield 61 according to this embodiment, since the upper cover 15 and the lower cover 16 are provided so as to further surround the above-mentioned shield space S1 from the outside thereof, the shield space inside the shield space S1 is provided. Leakage of nitrogen gas in S1 to the outside is prevented as much as possible, and the nitrogen gas concentration in the space S1 can be maintained in a high state.

Moreover, in this case, the upper cover 15 and the lower cover 16 are attached to the frame 10 and the frames 10 and 10 are also used as members for forming the outer shielded space S2. It realizes a structure that is easy to perform, such as maintenance. Further, since the lower cover 16 is constructed such that the shield plates 26a to 26d shield the gap with the solder bath 8'by the molten solder in the solder bath 8'as well as the side shield plates 55A and 55B, Can be simplified and the angle of the conveyor 2 can be freely adjusted.

As described above, according to the present invention, in a jet type soldering apparatus which is a carrierless type and which has a transport mechanism of varying a transport angle and a transport width, at least a portion of the nitrogen corresponding to the soldering process is required to have nitrogen. Although it has been made possible to create an atmosphere, the present invention described above enables the parts other than the soldering process, that is, the fluxer part or the preheater part to perform the processes other than the soldering process in a nitrogen atmosphere. Providing an enclosure such as the shield 61 is not excluded.

In the shield 61, the top plate 17 of the upper cover 15 and the upper closing plate 50 are
It is also possible to provide a window made of a transparent member so that the soldering state can be confirmed even from above the shield 61.

[0054]

As described above, according to the nitrogen-filled jet-type soldering device according to the first aspect of the invention, the nitrogen-filled jet-type soldering device is a carrierless type and is provided with a carrying mechanism with a variable carrying angle and carrying width. In the device, in creating a shielded space having a required nitrogen atmosphere in the upper space of the solder tank for performing the soldering process, the shielded space can be a very narrow space between both tracks of the conveyor, This makes it possible to easily create a nitrogen atmosphere having an extremely high nitrogen concentration. Moreover, in creating the narrow shielded space, the lower part of the side shield plate is immersed in the molten solder in the solder bath, and the molten solder forms a part of the shielded space. This has an excellent effect that the connection with the solder bath in the formation can be simplified and the angle adjustment and the width adjustment of the conveyor can be performed without any restriction.

According to the nitrogen-enclosed jet type soldering device of the second aspect, the above-mentioned shielded space is doubled by the upper cover and the lower cover, and the nitrogen gas in the inside shielded space is exposed to the outside. Leakage can be prevented as much as possible, and the nitrogen gas concentration in the shielded space can be maintained at a high state.

According to the nitrogen-filled jet type soldering device of the third aspect, the upper cover and the lower cover are attached to a frame, and the frame is used as a member for forming an outer shielded space. As a result, a rational and easy-to-maintain configuration is realized. In addition, the lower cover is also configured to shield the gap with the solder tank by the molten solder in the solder tank with the shield plate, so that the engagement with the solder tank can be simplified and the angle of the conveyor can be freely adjusted. It has an excellent effect that it can.

[Brief description of drawings]

FIG. 1 is a front sectional view showing a solder bath portion of a nitrogen-filled jet-type soldering device according to an embodiment of the present invention.

2 is a partial cross-sectional side view of FIG.

FIG. 3 is a plan view showing a lower cover of the shield according to the present embodiment.

FIG. 4 is a side view of the lower cover shown in FIG.

FIG. 5 is a front view showing an embodiment of a shutter that constitutes the shield according to the present embodiment together with a conveyor and the like.

FIG. 6 is a perspective view showing the shutter shown in FIG.

FIG. 7 is a perspective view showing an example of a jet type soldering device.

[Explanation of symbols]

1 Jet-type soldering device 2 Transport conveyors 2a, 2b Track 8'Solder tank 10 Frame 15 Upper cover 16 Lower cover 25 Opening 26a, 26b, 26c, 26d Shield plate (protruding plate) 30 Shutter 50 Upper closing plate 55A, 55B Side shield plate 60 Nitrogen-enclosed jet-type soldering device 61 Shield S1, S2 Shield space

Claims (3)

[Claims] 1. A solder tank is arranged below a conveyor for conveying soldered products, which has a pair of parallel tracks whose distances from each other can be adjusted. At least the soldering step is performed in a nitrogen atmosphere. A nitrogen-filled jet-type soldering device comprising a shield for forming a shielded space including the transfer conveyor in the upper part of the solder tank, as described above, wherein the shield is one of the pair of tracks. An upper closing plate that covers the upper part at least between both tracks and a length substantially corresponding to the solder tank, and a side shield plate that is attached to each of the tracks and projects downward toward the solder tank. Further, the upper blocking plate is close to the upper surface of each track at least in the fixed position or the moving range of each track, while the side shield plate is at least its side. Nitrogen-filled nozzle-type soldering apparatus, characterized in that the end is immersed in the molten solder in said solder bath. 2. An upper cover is provided above the upper blocking plate and extending between frames provided on both sides of the transport conveyor in parallel with the transport conveyor, and an upper cover is provided below the frame between the frames. 2. The nitrogen-enclosed jet-type soldering device according to claim 1, further comprising a lower cover that closes at least a gap between the frame and the solder bath. 3. The lower cover has an opening through which the solder bath is seen, and a projecting plate extending downward from the periphery of the opening is formed toward the solder bath. 3. The nitrogen-enclosed jet-type soldering device according to claim 2, wherein at least the lower end is immersed in the molten solder in the solder bath.