JPH11204932A - Air blower device for reflow soldering machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable blowing hot air uniformly on the whole region of a board so as to prevent generation of temperature irregularity on a printed circuit board. SOLUTION: A conical member 10, provided with a blower 7 where a rotating shaft 7a is arranged orthogonally intersecting with a flat member 1 and an air duct 8 which is concentrical with the rotating shaft 7a of the blower 7 and forms a conical-shaped ventilator 11 in the air duct 8, is arranged concentrically with the rotating shaft 7a in the state wherein the tip 10a of the conical member 10 is opposing to the flat member 1. Also, a fixed vane 13, with which the gas sent from the blower 7 is formed into an eddy, is arranged in the ventilator 11 formed between the conical member 10 and the inner circumferential surface of the air duct 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blower for a reflow soldering machine, and more particularly to a printed circuit board which is conveyed by a conveying device such as a chain conveyor, and which is blown with hot air to the creamed solder. And a blower for a reflow soldering machine for soldering electronic components to a substrate.

[0002]

2. Description of the Related Art Conventionally, as an apparatus of this kind, for example, FIG.
As shown in FIG. 2, a blower d having a rotation axis c orthogonal to a planar body b having a large number of pores a, and a wind tunnel e concentric with the rotation axis c of the blower d. (For example, see Japanese Patent Application Laid-Open No. 9-237967).

In FIG. 1, f is a printed circuit board on which electronic components g are mounted, and h is a transfer device such as a chain conveyor for transferring the board f. Also, i is a carrier provided with support pins j. The substrate f is mounted on the carrier i via the support pins j, and is soldered by hot air while being conveyed with the carrier i.

[0004]

In this type of apparatus, hot air can be uniformly blown onto the substrate in order to prevent a difference in soldering performance and soldering state depending on the mounting position of the electronic component. It is desirable that the film be formed so as not to cause temperature unevenness.

However, in the conventional apparatus, as described above, since the wind tunnel is merely formed concentrically with the rotation axis of the blower, the wind tunnel merely guides the gas to the planar body and disperses the gas to the side. It simply had a function to prevent it.

Therefore, in the conventional apparatus, the gas sent from the blower is likely to be guided to the planar body in a state where the wind pressure is large at the periphery of the wind tunnel due to the action of the centrifugal force and small at the axial center position.
According to the conventional apparatus, there is a problem that unevenness is generated in the hot air blown out from the planar body, the entire area of the substrate cannot be heated uniformly, and as a result, the electronic components cannot be soldered accurately and stably. .

[0007] The present invention is to solve such a problem of the conventional product. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a blower of a reflow soldering machine formed so that hot air can be uniformly blown over the entire area of a printed circuit board so that temperature unevenness does not occur on the printed circuit board.

[0008]

The present invention employs the following technical means to solve the above-mentioned problems. That is, the present invention is a blowing device of a reflow soldering machine for blowing a heating gas onto a printed circuit board 2 through a planar body 1 having a large number of pores 1a to solder an electronic component 3, A blower 7 in which a rotating shaft 7a is disposed orthogonal to the planar body 1.
A wind tunnel 8 concentric with the rotating shaft 7 a of the blower 7, and a wind tunnel 8 in which the tip 10 a is disposed concentrically with the rotating shaft 7 a in a state where the tip 10 a faces the planar body 1 in the wind tunnel 8. A conical body 10 that forms a conical ventilation path 11 in the inside 8, and is provided from the blower 7 to the ventilation path 11 formed between the cone 10 and the inner peripheral surface of the wind tunnel 8. And a stationary wing 13 for vortexing the gas (claim 1).

Here, the planar body 1 having a large number of pores 1a is formed into a planar shape by providing a punched metal or the like having a large number of small holes or slits, or a punched metal or the like in a sandwich shape. There is a heating device. In the case where the planar body 1 is the former, a heater for heating the gas is provided at an appropriate position such as a circulation path. In the case of the apparatus of the present invention, examples of the blower 7 include a fan such as a sirocco fan and a blower.

In the apparatus of the present invention, as shown in FIG. 1 and the like, a diffusing portion 9 for diffusing and guiding gas toward the planar body 1 is provided at the outlet 8a of the wind tunnel 8. It is preferable that the diffusion portion 9 is formed to have a conical inclined surface portion 9a which is connected to the periphery of the outlet 8a and whose diameter is gradually enlarged toward the planar body 1 (claim 2).

In the case of the apparatus according to the present invention, the gas can be radially diffused from the outlet 8a of the wind tunnel 8 by the diffusing section 9 and diverged. Therefore, in this case, there is an advantage that it is possible to cope with the substrate 2 having a size that does not fit within the opening area of the outlet 8a without increasing the size of the outlet 8a, in other words, without increasing the size of the wind tunnel 8. There is.

In this case, the device of the present invention may be formed so that the diffusion portion 9 includes a square enclosure 9b formed from the periphery of the front end of the inclined surface 9a.

In this case, the gas can be efficiently guided to the planar body 1 without escaping to the side by the above-mentioned enclosure 9b, and the substrate 2 which cannot be accommodated in the opening surface of the inclined surface 9a.
There is an advantage that it is possible to cope with this without increasing the size of the wind tunnel 8.

Further, in the case of the present invention, as shown in FIG. 1 and the like, the outer shape of the wind tunnel 8 is provided with a conical outer portion 8b whose diameter is gradually reduced toward the outlet 8a, and has an abacus shape. (Claim 4).

In this case, since the outer shape of the wind tunnel 8 is in the shape of an abacus, the size of the wind tunnel 8 can be reduced and the space can be saved, and the side of the gas inlet 8c opposite to the outlet 8a is formed in a conical shape. Therefore, by arranging the blower 7 at this location, the gas can be smoothly guided toward the outlet 8a by using the inclined inner peripheral surface of the wind tunnel 8.

Here, the abacus pearl shape means a cross-sectional shape formed by joining conical shapes with enlarged sides, and as shown in FIG. A cylindrical portion 8d having the same diameter is formed in the cylindrical portion.
The case where the outer shape is formed in a reverse tapered shape through the above is also included.

However, the present invention is not limited to the case where the outer shape of the wind tunnel 8 is formed in an abacus shape. That is, the wind tunnel 8 may be formed by simply forming a cylindrical shape, for example, and providing a conical tapered portion whose diameter is gradually reduced toward the outlet 8a.

Further, in the case of the apparatus of the present invention, it is preferable that a plurality of fixed blades 13 are arranged at equal intervals around the axis of the wind tunnel 8 (claim 5).

In the apparatus of the present invention, the fixed wings 13 may be formed in a spiral shape, for example. However, forming the fixed wings 13 with a plurality of fixed wings 13 makes the wind tunnel 8 longer than in the case of forming a spiral shape. It is easy to generate an appropriate eddy current without any. Therefore, in the case of the device of the present invention, the device can be made more compact,
Space saving can be achieved.

The fixed wing 13 is fixed to the inner peripheral surface of the wind tunnel 8 or the outer peripheral surface of the cone 10 by, for example, welding. In the case of the device of the present invention,
May be appropriately selected depending on various conditions such as the output of the blower 7, the size of the wind tunnel 8, and the like.

[0021]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Reference numeral 1 denotes a planar body having a large number of pores 1a. In this embodiment, the planar body 1 is a planar heater having a large number of slits as the pores 1a. Reference numeral 2 denotes a printed circuit board on which electronic components 3 are mounted. The substrate 2 is placed on a net-shaped carrier 4 via support pins 4a, and is transported together with the carrier 4 on a chain conveyor 5.

Reference numeral 6 denotes a heating chamber for housing the apparatus of the present invention. The heating chamber 6 is usually arranged in series for preheating, reflow soldering, and slow cooling along the extending direction of the chain conveyor 5, and is filled with an inert gas such as nitrogen gas. ing. In the present embodiment, the apparatus of the present invention is housed in the heating chamber 6, and is disposed above and below the chain conveyor 5 so as to face each other.

Reference numeral 7 denotes a blower in which a rotating shaft 7a is disposed orthogonal to the planar body 1. In this embodiment, the blower 7 is configured by a sirocco fan, and is configured to rotate in a counterclockwise direction by a motor 7b disposed outside the heating chamber 6.

Reference numeral 8 denotes a wind tunnel concentric with the rotating shaft 7a of the blower 7. In this embodiment, the wind tunnel 8 is
conical outer part 8b whose diameter is gradually reduced toward a
The outer shape is formed substantially in the shape of an abacus.

In this embodiment, a diffuser 9 is provided at the outlet 8a of the wind tunnel 8 for diffusing and guiding the gas toward the planar body 1. In this embodiment, the diffusing portion 9 is a conical inclined surface portion 9a connected to the periphery of the outlet 8a and having a diameter gradually enlarged toward the planar body 1.
And a square enclosure 9b formed from the periphery of the tip of the inclined surface 9a.

Reference numeral 10 denotes a conical body that forms a conical ventilation passage 11 in the wind tunnel 8. The conical body 10 is disposed concentrically with the rotating shaft 7 a in the wind tunnel 8 with the tip 10 a facing the planar body 1. The tip 10a of the cone 10 is flattened in this embodiment, and faces the diffusion portion 9 described above. In this embodiment, the cone 10 is fixed in the wind tunnel 8 by a support rod 12 erected on the inner peripheral surface of the wind tunnel 8 on the side of the gas intake port 8c.

Reference numeral 13 denotes fixed blades for vortexing the gas sent from the blower 7. The fixed wings 13 are provided in the ventilation passage 11 formed between the cone 10 and the inner peripheral surface of the wind tunnel 8.
Are welded to the inner circumferential surface of the wind tunnel 8 at equal intervals around the axis of the wind tunnel 8.

Next, the operation of the present invention will be described. In the apparatus of the present invention, when the blower 7 rotates, the inert gas filling the heating chamber 6 is taken into the wind tunnel 8 from the gas inlet 8c, and is sent to the planar body 1 from the outlet 8a through the ventilation path 11.

In this case, in the apparatus of the present invention, as described above, the ventilation path 11 is formed in a conical shape whose diameter decreases toward the outlet 8a, and the ventilation path 11 is formed with the fixed blades 13. . Therefore, at the outlet 8 a, the gas is narrowed down to the axial center side of the wind tunnel 8 in the ventilation passage 11, vortexed by the fixed wings 13, and flows around the outlet 8 a. As a result, according to the device of the present invention, the gas is blown out from the outlet 8a at the same wind pressure and wind speed through the outlet 8a by the synergistic action of the conical ventilation passage 11 and the fixed blade 13.

In the case of this embodiment, the blown gas is heat-exchanged while passing through the pores 1a of the planar body 1 to become a heated gas, and the heated gas is uniformly sprayed onto the substrate 2. Then, the cream solder is melted, and the electronic component 3 is soldered to the substrate 2. The gas after soldering flows inside the heating chamber 6 outside the wind tunnel 8, flows into the wind tunnel 8 again through the gas inlet 8c, and circulates inside the heating chamber 6.

[0031]

As described above, the apparatus according to the present invention is provided with a conical ventilation path for equalizing the gas flow at the outlet of the wind tunnel and the fixed wings.

Therefore, in the case of the apparatus of the present invention, since hot air is blown out from the fine holes of the planar body at the same flow rate, the entire area of the substrate can be uniformly heated. As a result, according to this, it is possible to eliminate the occurrence of temperature unevenness on the printed circuit board, and to reliably solder the electronic component to the board in a stable state without causing a difference in the mounting position of the electronic component. It has the effect.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a preferred embodiment of the device of the present invention with a part thereof being cut away in a use state.

FIG. 2 is a partially cutaway perspective view of the same device in use.

FIG. 3 is a front view of the same device.

FIG. 4 is a plan view of the same device.

FIG. 5 is a partially cutaway perspective view showing the relationship between the above device and a printed circuit board.

FIG. 6 is a longitudinal sectional view showing a conventional example in which a part in a use state is cut away.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Planar body 1a Micropore 2 Printed circuit board 3 Electronic component 7 Blower 7a Rotation axis 8 Wind tunnel 10 Conical body 10a Tip part 11 Air passage 13 Fixed wing

Claims (5)

[Claims] 1. A blower of a reflow soldering machine for blowing a heating gas onto a printed circuit board through a planar body having a large number of pores to solder electronic components, wherein the planar body is provided. A blower having a rotation axis orthogonal to the blower, a wind tunnel concentric with the rotation axis of the blower, and concentric with the rotation axis in a state where the tip of the blower is opposed to the planar body in the wind tunnel. A conical body arranged in the wind tunnel to form a conical ventilation passage in the wind tunnel;
A reflow solder, comprising: fixed wings arranged in the ventilation path formed between the cone and the inner peripheral surface of the wind tunnel to vortex gas sent from a blower. Blower of tag machine. 2. A diffuser for diffusing gas toward a planar body is provided at an outlet of the wind tunnel, and the diffuser is connected to a periphery of the outlet to gradually reduce the diameter of the planar body. The blower for a reflow soldering machine according to claim 1, characterized in that the blower is formed with a conical inclined surface portion that is enlarged toward (2). 3. The air blower for a reflow soldering machine according to claim 2, wherein the diffusion portion is formed to have a square enclosure formed continuously from the periphery of the tip of the inclined surface. 4. The wind tunnel according to claim 1, wherein the wind tunnel is formed in an abacus shape with a conical outer portion whose diameter is gradually reduced toward the outlet. The blower of the reflow soldering machine according to the above. 5. The blower for a reflow soldering machine according to claim 1, wherein a plurality of fixed blades are arranged at equal intervals around the axis of the wind tunnel.