JPH04129287A - Enameled substrate with screwed part - Google Patents

Abstract

PURPOSE:To avoid an accident such as cut of a circuit by providing a screwed part having a groove having no enameled layer for isolating from each other between a conductor circuit region of an enameled substrate and the screwed part of the substrate. CONSTITUTION:Threaded holes 4 are formed at both ends of an enameled substrate 1. A groove 6 is so formed by cutting an enameled layer of the part by sand-blasting as to isolate the conductor circuit region 2 of the substrate 1 and a screwed part 7. Thus, a crack 8 in the enamel due to screw clamping does not affect the circuit part and safety and the circuit part is assured.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an enameled substrate having a screwed portion.

More specifically, the present invention relates to an enamel board that does not affect the circuit even if the screw-fastening portion is tightened.

[Conventional technology]

Conventionally, even when a hole for screwing is bored in a metal core, the entire board is glazed and enameled, and a conductive circuit is formed on this board.

Place this enamel board with holes for screws into the casing, etc.
When using these holes to fasten with screws, there was a problem in that if the screws were tightened too strongly, cracks would form in the enamel, and these cracks would propagate and cut off adjacent circuits.

[Problem to be solved by the invention]

An object of the present invention is to provide an enameled board with a screw-fastening part, so that when the board is screwed to another support, even if cracks occur in the enamel layer around the screws when the screws are tightened, the conductor circuit will not be affected. Our goal is to provide a non-enamel substrate.

[Means to solve the problem]

The present invention is an enameled substrate having a screw fixing portion having a groove without an enameled layer separating the conductor circuit region of the enameled substrate and the screw fixing portion of the enameled substrate from each other.

A method of forming a groove without an enamel layer is to set a groove about one inch wide around the screw hole or on the boundary line between the conductor circuit area and the screw hole, and then remove the enamel layer in this area. The enamel frit is electrocuted by scraping off the enamel layer by means such as sandblasting or mechanical cutting, or by printing Ni paste on the pretreated metal core where the grooves are to be formed, or by applying partial Ni plating. When deposited and fired, no enamel is attached to the portion where the Ni layer is formed, so it is possible to form a groove without an enamel layer.

With this configuration, even if a crack occurs in the enamel layer around the hole due to strong tightening at the screwed part, the propagation of the crack will be stopped in the groove part where there is no enamel layer, and the conductor circuit area will be prevented from propagating. Therefore, accidents such as circuit breakage can be avoided.

〔Example〕

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

The drawings will be explained. FIG. 1 shows a cross-sectional elevation view of an enameled substrate with an isolation groove without an enameled layer between the conductor circuit area and the screwed part, screwed to a base support.

FIG. 2 is a plan view of a portion of the enamel substrate provided with the isolation groove.

1 is an enamel substrate, 2 is a conductor circuit area, 3 is a conductor circuit,
4 is a hole for screw fixing, 5 is a screw, 6 is an isolation groove, 7 is a screw fixing part of the board, 8 is a crack that occurs when tightening a screw, 9
is the base support to which the enamel substrate is attached.

[Example 1] Two M3 screw holes were provided at both ends of an enamel substrate measuring 35 μl×67 fins×0.8 m+*t. 1 so as to isolate the conductive circuit area of this enamel board from the screwed part.
Two grooves each having a width of mI and a length of 35 mm were formed by sandblasting the enamel layer in this area.

When this M3 screw was tightened with a torque of 6 kg-(7), a crack occurred in the enamel layer of the screwed part under the washer.

However, this crack was also stopped by the groove, and no crack occurred in the central circuit section.

[Example 2] Holes for screw fixing were drilled in a pretreated core iron plate, a groove was planned to separate the hole from the circuit area, Ni plating was applied partially where the groove was needed, and then enamel frit was applied. was electrodeposited and fired. Since no enamel was formed on the Ni plating, it was possible to form a groove without an enamel layer. When the M3 screws were tightened to a torque of 6 kg-■ in the same manner as in Example 1, a crack appeared in the enamel layer under the washer where the screws were fixed, but no cracks occurred in the central circuit section. Ta.

〔Effect of the invention〕

Since the enamel board of the present invention has a groove separating the conductor circuit part and the screwed part, cracks in the enamel caused by screw tightening do not affect the circuit part, and the safety of the circuit part can be ensured.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional elevational view of an enamel substrate provided with isolation grooves. FIG. 2 is a plan view of FIG. 1. 1... Enamel board, 2... Conductor circuit area, 3...
・Conductor circuit, 4... Screw fixing hole, 5... Screw, 6
...Isolation groove, 7...Screwed part, 8...Crack.

Claims (1)

[Claims] An enamel substrate having a screw fixing part having a groove without an enamel layer separating the conductive circuit area of the enamel substrate and the screw fixing part of the enamel substrate from each other.