JP3829062B2 - Double-side heat treatment conveyor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a double-sided heat treatment conveyor used in a continuous heat treatment furnace or the like.
[0002]
[Prior art]
Conventionally, various substrates for electronic components are subjected to heat treatment for firing, for example, paste printed on the surface in the manufacturing process, and are generally subjected to double-sided heat treatment as electronic components are mounted on both sides. It has become. This double-sided heat treatment is performed in a heat-treatment furnace having a predetermined structure, and a double-sided heat-treating conveyor is usually used as means for transporting the workpiece into the heat-treatment furnace. Here, a metal mesh belt is generally used as the conveyor, and heat-resistant steel is generally used as a material constituting the metal mesh belt.
[0003]
[Problems to be solved by the invention]
However, the double-side heat treatment conveyor using the metal mesh belt as a transport belt has the following problems (1) to (3). That is,
(1) The heat resistant steel constituting the metal mesh belt cannot be used in a high temperature range exceeding about 1200 ° C.
(2) During heat treatment of workpieces, metal scales such as oxide scales and abrasion powders are likely to be generated from the transport zone moving in the furnace, and foreign matters such as metal scales may adhere to the workpiece surface and contaminate the workpieces. is there. This is extremely undesirable for electronic parts.
(3) In order to heat-treat the entire surface of the workpiece evenly, it is necessary to support and heat-treat the workpiece at a certain height from the metal mesh belt surface. A tray for loading workpieces is indispensable. Therefore, there is a problem that not only the cost is increased but also the production efficiency is lowered.
[0004]
The present invention has been made to solve the problems of conventional double-side heat treatment conveyors, and its purpose is to widen the operating temperature range at high temperatures, and to prevent workpieces from adhering to foreign objects such as metal scales. An object of the present invention is to provide a double-side heat treatment conveyor that prevents contamination and does not require a workpiece lifting jig or the like.
[0005]
[Means for Solving the Problems]
Therefore, in order to achieve the above-described object, a double-sided heat treatment conveyor according to the present invention includes a transport element that can move endlessly in a heat treatment furnace, and simultaneously conveys both surfaces of a workpiece transported into the heat treatment furnace by the transport element. It is a conveyor for double-sided heat treatment configured to be heat-treated,
The transport element is made of ceramic;
A plurality of pairs of link plates opposed to each other, a pin connecting the plurality of adjacent link plates adjacent to each other in the conveying direction, and a roller rotatably fitted to the pin,
Wherein the link plates are viewed contains a plurality of pairs of link plates that work receiving portion is formed for the point contact with the side edge of the workpiece or in line contact with the top surface for supporting the workpiece,
The roller includes a roller central portion that is eccentrically supported downward with respect to a pin axis, and roller both sides that are disposed on both sides of the roller central portion and are coaxially supported with the pin axis. It is characterized in that it is composed of a (claim 1).
[0006]
In the double-sided heat treatment conveyor according to the above configuration (Claim 1), since the conveying element is composed of ceramic, the operating temperature range at high temperature can be expanded, and foreign matters such as metal scales are not generated. It is possible to prevent contamination of the workpiece due to foreign matter adhesion. Further, by forming a work receiving portion on the upper surface of the link plate for supporting the work by making point contact or line contact with the side edge of the work, interference with the work surface of the transport element is avoided as much as possible. In this state, the workpiece can be supported and subjected to double-sided heat treatment. Further, since the roller central portion is eccentrically supported downward with respect to the axis of the pin, the heat in the continuous heat treatment furnace that has entered the back surface side of the workpiece is diffused from the central portion to both side portions. It becomes easy to heat-treat evenly.
[0007]
In the double-side heat treatment conveyor (Claim 1), it is preferable that the workpiece receiving portion is formed by a tapered surface formed on an upper surface of the link plate (Claim 2). In this case, the taper surface supports the work in a state in line contact with the side end of the work.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a double-sided heat treatment conveyor according to the present invention will be described with reference to the drawings.
FIG. 1 is an enlarged plan view of an essential part of a conveyor for double-sided heat treatment according to one embodiment of the present invention. FIG. 2 is a side view of the main part of the double-side heat treatment conveyor as seen from the conveying direction, and FIG. 3 is an enlarged view showing the vicinity of the workpiece receiving part in FIG.
[0009]
In FIG. 1, a transport element 1 can move endlessly in a continuous heat treatment furnace, for example, and both surfaces of a workpiece W such as an electronic component substrate transported into the continuous heat treatment furnace by the transport element 1 simultaneously. It is used for a double-sided heat treatment conveyor configured to be heat-treated. Specifically, the conveying element 1 is stretched between a driving wheel and a driven wheel (both are sprocket wheels and the like, not shown) of the conveyor disposed at the entrance and exit of the continuous heat treatment furnace, It moves endlessly in the continuous heat treatment furnace. In addition, in order to make this invention easy to understand, the conveying element 1 shown in the figure is only an example of a part of the excerpt, and in an actual double-sided heat treatment conveyor, the same conveying element 1 is used. A plurality are used between the driving wheel and the driven wheel and arranged in parallel.
[0010]
The conveying element 1 is made of ceramic and includes an inner link plate 2 and an outer link plate 3 as link plates, a roller 4 and a pin 5. The basic structure of the conveying element 1 is not different from that of a normal chain structure.
Specifically, in the transport element 1, a plurality of inner link plates 2 are arranged in the transport direction in pairs that are opposed to each other. The outer link plates 3 are arranged to face each other in pairs between the adjacent inner link plates 2. The inner link plate 2 and the outer link plate 3 are connected by the pin 5. A roller 4 is rotatably fitted to the pin 5 between a pair of inner link plates 2 arranged to face each other. The material of the ceramic used for the conveying element 1 is, among many, such as alumina, zirconia, silicon carbide and the like, considering the upper limit of the heat treatment temperature of the workpiece W to be subjected to the double-side heat treatment, the heat resistance and wear resistance required for the ceramic. In addition, it is appropriately selected in consideration of corrosion resistance and the like.
[0011]
As shown in FIG. 2, the roller 4 is, for example, a roller center portion 4a that is eccentrically supported downward with respect to the axis of the pin 5, and is disposed on both sides of the roller center portion 4a. It comprises roller both sides 4b and 4b supported coaxially with the axis of the pin 5, and when the conveying element 1 travels, the rollers both sides 4b and 4b slide on the rail 8 of the conveyor. ing. Here, the space between the roller central portion 4a and the workpiece W is set to be considerably wider than the space between the roller side portions 4b and the workpiece W, and the back side of the workpiece W is The heat in the continuous heat treatment furnace that has entered is diffused from the central part to both side parts, so that the workpiece W is easily heat-treated evenly.
[0012]
The conveying element 1 is stretched endlessly with a predetermined tension between the driving wheel and the driven wheel disposed at the entrance and exit of the continuous heat treatment furnace. At this time, the tooth portions of the driving wheel and the driven wheel The roller both sides 4b and 4b of the roller 4 constituting the conveying element 1 are meshed with each other, and the conveying element 1 moves endlessly in the conveying direction in the continuous heat treatment furnace by rotational driving of the driving wheel, A double-sided heat treatment is performed on the workpiece W to be conveyed.
[0013]
On the upper surface of the inner link plate 2, a tapered surface 6 is formed as a work receiving portion. As shown in FIGS. 2 and 3, the tapered surface 6 is formed such that the upper surface is tapered to have a downward slope inward in the width direction of the conveying element 1, for example. The workpiece W is supported in line contact with the side end of the workpiece in the conveying direction. By forming such a tapered surface 6, for example, as shown in FIG. 3, a gap 7 is formed between the tapered surface 6 and the side end of the workpiece W, and the workpiece W is substantially the entire back surface thereof. Is supported in a non-contact state with the conveying element 1, and a double-sided heat treatment is performed. In this conveying element 1, a pair of inner and outer links are provided such that the side end of the workpiece W is in line contact with the tapered surface 6 without the back surface of the workpiece W being in surface contact with the upper surface of the outer link plate 3. Each width dimension of the plates 2 and 3 is adjusted according to the width dimension of the workpiece W.
[0014]
In the double-sided heat treatment conveyor of the present embodiment configured as described above, since the transport element 1 is made of ceramic, the use temperature range at a high temperature is widened compared to the metal mesh belt in the above-described conventional example. Can do. Further, unlike the metal mesh belt, foreign matter such as a metal scale is not generated, so that contamination of the workpiece due to foreign matter adhesion can be prevented. Therefore, the reliability of the obtained product can be remarkably improved.
Further, since the taper surface 6 is formed on the upper surface of the inner link plate 2, the workpiece W is supported in a state where interference with the surface (back surface) of the workpiece W of the transport element 1 is avoided as much as possible, and both-side heat treatment is performed. It can be carried out. As a result, the lifting jig and tray in the conventional example are not required, the number of parts can be reduced, the working efficiency is remarkably improved, and the maintenance is also reduced.
[0015]
In the above description, the configuration in which the tapered surface 6 as the workpiece receiving portion is provided on the upper surface of the inner link plate 2 has been described. However, the present invention is not limited to this, and for example, the workpiece receiving portion is the workpiece. What is necessary is just to support the said work W by carrying out a point contact or a line contact to the side edge part of W. Specifically, as shown in FIG. 4, a tapered surface 6 having a downward gradient inward in the width direction of the transport element 1 may be formed on the upper surface of the outer link plate 3 as a work receiving portion. When the tapered surface 6 is formed on the upper surface of the outer link plate 3 as described above, the widths of the pair of inner and outer link plates 2 and 3 are set so that the back surface of the work W does not come into surface contact with the upper surface of the inner link plate 2. The dimensions and the like are adjusted according to the width dimension of the workpiece W. Further, instead of the line contact, a point contact may be used to support the workpiece W. In this case, instead of the tapered surface 6, needle-like or hemispherical projections are provided on the inner link plate 2 or the outer link. What is necessary is just to form in the plate 3. FIG.
[0016]
【The invention's effect】
The present invention configured as described above has the following effects. According to the double-side heat treatment conveyor of claim 1, since the conveying element is made of ceramic, it is possible to widen the operating temperature range at high temperature and to prevent foreign matters such as metal scales from being produced. It is possible to prevent the workpiece from being contaminated. In addition, since the work receiving part for supporting the work by making point contact or line contact with the side end part of the work is formed on the upper surface of the link plate, interference with the work surface of the transport element is prevented. The workpiece can be supported and subjected to double-sided heat treatment while avoiding as much as possible. Furthermore, since the conventionally used floating jig and tray are not required, the number of parts can be reduced and the work efficiency can be improved. In addition, since the roller central portion of the conveying element is eccentrically supported downward with respect to the axis of the pin, the heat in the continuous heat treatment furnace that has entered the back side of the workpiece is diffused from the central portion to both side portions. Thus, the workpiece can be easily heat-treated evenly.
[0017]
Further, according to the double-side heat treatment conveyor of claim 2, since the taper surface supports the work in a state of being in line contact with the side end portion of the work, the conveying element can be used with a simple configuration without using a lifting jig or the like. In a state where interference with the workpiece surface is avoided as much as possible, both-side heat treatment of the workpiece can be performed.
[Brief description of the drawings]
FIG. 1 is an enlarged plan view of a main part of a double-sided heat treatment conveyor according to an embodiment of the present invention.
FIG. 2 is a side view of the double-side heat treatment conveyor as seen from the carrying direction.
FIG. 3 is an enlarged view showing the vicinity of a work receiving portion in FIG. 2;
FIG. 4 is an enlarged view showing the vicinity of a work receiving portion according to another embodiment.
[Explanation of symbols]
1 Conveying element 2 Inner link plate 3 Outer link plate 4 Roller 5 Pin 6 Tapered surface (work receiving part)
7 Clearance W Workpiece

Claims (1)

A conveyor for double-sided heat treatment, comprising a transport element that can move endlessly in a heat treatment furnace, and configured to simultaneously heat-treat both surfaces of the workpiece transported into the heat treatment furnace by the transport element,
The transport element is made of ceramic;
A plurality of pairs of link plates opposed to each other, a pin connecting the plurality of adjacent link plates adjacent to each other in the conveying direction, and a roller rotatably fitted to the pin,
Wherein the link plates are viewed contains a plurality of pairs of link plates that work receiving portion is formed for the point contact with the side edge of the workpiece or in line contact with the top surface for supporting the workpiece,
The roller includes a roller central portion that is eccentrically supported downward with respect to a pin axis, and roller both sides that are disposed on both sides of the roller central portion and are coaxially supported with the pin axis. duplex heat treatment conveyor, characterized in that it is composed of a.

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