JPH0479395A - Enameled circuit board - Google Patents

Abstract

PURPOSE:To prevent a temperature fuse from being damaged, by providing a recessed part whose area is the same as the plane of the fuse or somewhat larger, and whose depth is the same as the thickness of the fuse or somewhat deeper, and by forming the temperature fuse in the recessed part. CONSTITUTION:A recessed part 5 is provided beforehand on the core of an enameled board 1, and after enameling the core, a circuit 2 and a protective glass layer 3 are formed thereon. Thereafter, a temperature fuse 4 is formed. For example, on the place predetermined to form the fuse, the range predetermined to form the recessed part is set, and groove holes of 0.1-0.3mm in width are provided on the places around the range, except for the places predetermined to form conductor circuits. Then, the core is put on the flat die face of a press, and by pressing the part predetermined to form the recessed part with the punch of the press, the recessed part is formed. By providing the groove holes, even when pressing the part predetermined to form the recessed part, there is no possibility of a protruding part generating on the reverse of the core. The depth of the recessed part is made to be 0.1-0.3mm. Thereafter, after enameling the core and forming thereon the conductor circuit, the protective glass layer is formed thereon, and the temperature fuse is formed in the recessed part provided on an enamel.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hollow circuit board on which a temperature fuse is printed.

More specifically, the present invention relates to a hollow circuit board on which a thermal fuse is formed, which causes problems such as damage to the fuse due to overlapping during packaging, space factor during packaging, and pressure loss when the board is air-cooled.

[Conventional technology]

When forming a temperature fuse on a circuit board, paste solder is usually used and printed to a thickness of 0.1 to 0.30+nn by a screen or metal mask method.

Conventionally, these fuses have a slight bulge on the surface of the flat board as shown in Figure 4, so they can be damaged if they come into contact with other boards during manufacturing or packaging. However, there were problems such as loss of proper operating characteristics of the fuse.

Therefore, in order to avoid such problems, we have proposed attaching a metal cover over the fuse to prevent damage during packaging, transportation, etc., as shown in the cross-sectional view in Figure 5.

[Problem to be solved by the invention]

However, although this method is effective in preventing damage to printed thermal fuses, since they are formed protruding from the flat substrate surface, they are installed in the air duct of an automobile air conditioner and used for air cooling. It has been found that in such cases, problems such as pressure loss and wind noise may occur.

The purpose of the present invention is to solve the problem of the conventional hollow circuit boards that are formed by printing temperature fuses. To provide a hollow circuit board provided with a temperature fuse that is not damaged.

[Means to solve the problem]

The present invention provides a temperature fuse printed on a hollow circuit board with an area that is the same as the area of the fuse plane, or slightly larger than the area, and whose depth is the same as the thickness of the fuse to be formed. Alternatively, it is a hollow circuit board characterized in that a recessed portion slightly deeper than the thickness of the fuse is provided, and a temperature fuse is formed in the recessed portion.

It is desirable that the depth of the recessed portion for forming a temperature fuse on the substrate be in the range of 0.1 to 0.31 mm.

The method for making this recess is to first cut it off with a mini-milling machine or the like so that the recess of the required depth is cut into an area corresponding to the size of the fuse formed at the time of the iron plate of the core. There is a way to make a dent. However, it is preferable to use this method when the core thickness is as thick as 0.61 or more, and for thin cores such as 0.5m+g or less, the strength of the core may be slightly affected after that part is removed. There may be some problems.

The second method is to make indentations when pressing an iron plate. In this method, when making a dent in the iron plate, a slot is provided around the dent to provide relief for the amount of push-in, as shown in Figure 2, so that only a protrusion is produced on the back side. When making dents during pressing, it is desirable to make the dents with the press die surface flat.

By applying enamel glaze, forming a circuit, and forming a fuse on the iron plate in which the recessed portion has been formed in this manner, the enamel board having the temperature fuse provided in the recessed portion of the present invention can be obtained.

FIG. 1 shows a three-dimensional cross-sectional view of the temperature fuse section of the present invention.

A recessed portion 4 is previously provided in the core of the enamel substrate 1, and after enamel glazing 5, a circuit formation 2 and a protective glass layer 3 are formed, and then a temperature fuse formation 4 is performed.

The formed fuse surface will be at the same position as the circuit surface or lower.

〔Example〕

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to the same extent by these Examples.

When the board is a steel plate (core), as shown in the plan view in Fig. 2, the area where the dent is to be formed is set at the place where the fuse is planned to be installed, and the area around it excluding the area where the conductor circuit is to be formed has a width of 0. A slotted hole of 1 to 0.3 mm is made, and this core is inserted into the third
As shown in the figure, place it on the die surface of a flat press and press the dent forming part with the punch of the press to form a dent part.

The slot was made so that the part where the circuit formed on the board was located was not covered. By providing a slotted hole, there will be no protrusion on the back side even if the recessed part is pressed. The depth of the recessed portion shall be 0.1 to 0.3 mm.

After that, the enamel was glazed, a conductive circuit was formed, a protective glass layer was formed, and a temperature fuse was formed in the recessed part on the enamel.

In FIG. 2, 7 is a slot, 1 is a hollow substrate, 2 is a circuit, 5 is a recessed portion, and 4 is a temperature fuse.

Items with dents made by pressing were thinner in that area, but there were no particular problems in terms of strength, and there were no problems when applying enamel glaze, forming circuits, and forming fuses.

The surface of the fuse thus formed is located at or below the circuit surface of the board, and is completely flat overall, which prevents the fuse from being damaged during packaging and transportation.
It was also possible to eliminate the negative effects on the operating characteristics.

〔Effect of the invention〕

The enamel circuit board of the present invention, in which a temperature fuse is provided in the recessed part, has no bulge in the temperature fuse part, and is easy to pack and use.
Damage to the temperature fuse due to stacking during transportation can be prevented. Since there is no bulge, the space factor after stacking is good, and less packaging space is required.

The enamel board of the present invention has no protrusions even when it is installed in the middle of a ventilation path and the board is not cooled by the airflow before being used, such as when used to adjust the air volume of an automobile air conditioning blower. Therefore, it is easy to handle and can be used without increasing ventilation resistance.

FIG. 3 is a plan view of a hollow circuit board according to an embodiment in which a temperature fuse is formed in a hollow part of the hollow board having a hollow part formed by punching.

FIG. 3 is a cross-sectional elevational view showing the slotted hole of FIG. 2 and the recess formed by the punch of the press.

FIG. 4 shows a cross-sectional elevational view of a conventional flat enamel substrate with a temperature fuse provided thereon.

FIG. 5 shows a cross-sectional elevational view of a conventional thermal fuse on a flat substrate protected by a metal cover.

DESCRIPTION OF SYMBOLS 1... Hollow board, 2... Circuit, 3... Protective glass, 4... Temperature fuse, 5... Recessed part, 6...
...Enamel 7...Slot hole.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional elevational view of the temperature fuse portion of the hollow circuit board of the present invention. Figure 2 shows the core of the present invention with slotted holes and pressed by the applicant's representative Hiroshi Fujimoto Figure 1 Figure 4 Figure 2 Figure 5 Figure 3

Claims (1)

[Claims] The area where the thermal fuse is printed on the hollow circuit board is the same as the area of the fuse plane.
Alternatively, a recessed portion is provided which is slightly larger than the area and whose depth is equal to or slightly deeper than the thickness of the fuse to be formed, and a thermal fuse is formed in the recessed portion. Enamel circuit board.