JPS61128592A - Making of enamelled insulation metal substrate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to the production of a hollow insulated metal substrate in which a hollow insulating layer is formed on the surface of a metal core, and conductor patterns constituting a circuit are formed on the hollow insulating layer. This is about the method.

[Conventional example]

In recent years, as a circuit board, a glass glaze is applied to the surface of a metal core such as a copper plate and fired at a high temperature to form a single layer of enamel on the surface of the metal core, and this enamel layer is used as an insulating layer. This is an enamel insulating metal substrate on which a conductive pattern such as silver paste is printed
Enamel substrates (hereinafter simply referred to as enamel substrates) are attracting attention because of their excellent heat dissipation effects and mechanical strength.

In particular, enamel boards with a steel core have magnetic cores, so when used in motors etc.
It has become more effective.

By the way, such a hollow substrate has conventionally been produced by the method described below.

That is, a metal material such as a steel plate, which will become the metal core of the enamel board, is punched out in advance for the partial end faces and through holes of the enamel board that will be coated with the insulating layer, and then those parts are punched out. A enamel insulating layer is formed on the surface of the metal material, and a conductor pattern is formed on the enamel insulating layer, and then the metal material is heated so that the end face of the metal core excluding the partial end face portion is exposed. For each board, several pieces are punched and cut using a press or the like into a shape suitable for the hollow board.

[Problem that the invention seeks to solve]

In such a conventional method for manufacturing a hollow substrate,
Punching and cutting with a press etc. is performed including the part of the enamel insulating layer, and since this part is mainly composed of glass, cracks are likely to occur in the enamel insulating layer during press punching, and this crank part is likely to be missing. There was a problem with it.

In addition, if a conductor pattern of silver or the like is formed on the crank, even if it is of a fine rank, fine silver particles will grow inside the crank, and the so-called silver migration (migr-ion) will occur.
ation) phenomenon, which may cause an electrical short circuit between the metal core and the conductor pattern, resulting in poor insulation.

[Features of the invention]

The present invention includes the steps of uniformly firing and forming an enameled insulating layer on the surface of a metal material that will become a metal core, and cutting the metal material with the enameled insulating layer formed on the surface into a shape suitable for the enameled substrate to be manufactured. and a step of forming a conductor pattern constituting a circuit on the enamel insulating layer, and after the cutting step, the enamel insulating layer is fired again.

[Purpose of the invention]

An object of the present invention is to eliminate cracks by re-firing after forming by pressing.

〔Example〕

Hereinafter, a method for manufacturing a hollow substrate of the present invention will be explained using illustrated examples. Before entering into this explanation, the functions of the hollow substrate will be described below using a motor as an application example.

FIG. 1 shows the cross-sectional structure of a small motor equipped with such a hollow substrate. A stator magnet 3 made of an annular permanent magnet is fitted onto the inner peripheral surface of the magnet 2 .

Bearing holding part 2b formed in the center of stator case 2
An oil-impregnated metal 4 containing lubricating oil is attached to the rotary shaft 5, and this oil-impregnated metal 4 rotatably supports the output shaft portion 5a of the rotating shaft 5. A rotor core 6 having a plurality of salient poles is fitted onto the rotating shaft 5, and a coil 7 is further wound around the rotor core 6.

Further, a commutator 8 is fitted to the rotating shaft 5, and this commutator 8
Each winding end of the coil 7 is connected to the terminal. An enamel base [10 according to the present invention] is fitted into the upper opening of the stator case 2, and the enamel base 10 is fitted onto a mating step 2c provided at the opening end of the stator case 2.

On the other hand, a cup-shaped bearing holder 11 is attached to the center of the hollow substrate 10, and the oil-impregnated metal I2 stored in the bearing holder 11 holds the other shaft end 5b of the rotating shaft 5. It is rotatably supported. Rotating shaft 5
A seat plate 13 mounted within the bearing holder 11 is in contact with the shaft end 5b, and this seat plate 13 is adapted to receive the thrust force of the rotating shaft 5. Note that the reference numeral 14 is a brush whose base end is attached to the hollow substrate 10 and connected to the circuit of this substrate.

The enamel substrate 10 includes a metal core 10a made of a magnetic material such as a copper plate having a substantially disk shape, and a enamel insulating layer 10b formed on both sides thereof.
As shown in the figure, a conductor pattern 10c made of silver or copper paste is formed. Note that the enamel insulating layer lOb is formed by applying a glassy glaze to the surface of the metal core 10a and firing it.
It is formed to have a thickness of approximately 50 to 200 μm. Further, the conductor pattern 10c is configured as a control circuit that controls the rotational speed of the motor 1 using a semiconductor such as a film resistor, a capacitor, and an integrated circuit.

As shown in FIG. 2, the enamel substrate IO has a terminal piece 10d protruding from a part of the outer periphery.
After forming the enamel insulating layer 10b, the outer peripheral end surface is punched out using a press or the like so that the metal core 10a is exposed on the outer peripheral end surface except for 0d. By bringing the outer circumferential end surface and the inner surface of the opening of the stator case 2 into contact with each other, they are kept at the same potential (earth) to prevent the generation of electrical noise.

Note that the hollow substrate 10 is provided with through holes through which lead terminals of the elements are inserted.

Further, the hollow substrate 10 is fixed to the stator case 2 by a caulking piece of the stator case 2.

Here, to specifically describe the method for manufacturing the above-mentioned enamel substrate 10, in FIG.
0, a through hole 10e and holes 20a and 20b shaped as shown in the figure are formed by press punching.
Each of them is designed to be perforated. Of course, these holes are drilled through the metal material 20. Note that Figure 4 shows the state of several enamel boards before they are cut out, but in reality they are two plate-shaped metal materials.
0, a plurality of hollow substrates are cut out in a process described later.

One of the split holes 20a formed by the first press punching forms the terminal piece 10d, and
The dividing hole 20b forms a connecting piece 20C. In addition, the portions 2OA and 20 indicated by two-dot chain lines in FIG.
B is a part to be punched out in a cutting process to be described later, and in the process shown in FIG. 4, only the through hole 10e and dividing holes 20a, 20b are bored.

After drilling such holes 10e, 20a, 20b,
A powdered glaze containing glass as a main component and various mixtures is applied to both the front and back sides of the metal material 20 including all these holes by electrostatic coating, and this coated layer is heated to approximately 800°C. The enamel is baked in a furnace for several minutes to several tens of minutes to liquefy the glaze to form an enamel insulating layer on the surface of the metal material, and then cooled.

That is, this step is a step of uniformly firing and forming a hollow insulating layer on the upper and lower surfaces of the metal material.

Next, a cutting process is started in which the metal material 20 is punched and cut into a shape corresponding to the hollow substrate to be manufactured.

That is, in FIG. 4, the portions 20A, 20 indicated by two-dot chain lines
b is punched out using a press or the like, leaving a connecting piece 20c as shown in FIG. .

At this time, cracks may occur in the enamel insulating layer due to punching and cutting by the press, so it is fired again in the next step. That is, the metal material 20 shown in FIG. 5 is fired in a furnace at about 750'' C for several minutes to several tens of minutes, the glaze is made into a slow wave shape, the cracks are eliminated, and then the material is cooled.

Next, in FIG. 4, a conductor pattern 10c (second
(see figure). The conductor pattern 10c is formed by printing a paste of silver or copper on the enamel insulating layer by screen printing, and then printing a resistive paste on the enamel insulating layer and the conductor pattern 10c by screen printing. It is formed by firing in a furnace at about 600°C. That is, this step is a step of forming a conductive pattern and a resistive film on the hollow insulating layer.

The conductor pattern may be produced by bonding a thin copper plate to the surface of the hollow insulating layer and then etching it to form a predetermined wiring pattern in the same way as for ordinary printed wiring boards. Further, a thick film resistor may be formed after this step.

Thereafter, terminals of integrated circuits, capacitors, etc. (see FIG. 3) are inserted into the through holes 10e shown in FIG. 5, and these terminals are connected to the conductive patterns 10c shown in FIG. 2 by soldering. It has become. A bearing holder 11 as shown in FIG. 2 is mounted in a hole in the center of the hollow base plate 10 shown in FIG.

Next, the portion of the connecting piece 20c shown by the chain double-dashed line in FIG. 5 is cut using a press or the like.

In the manner described above, a hollow board as shown in FIG. 3 is produced as a completed product, and is installed in a small DC motor or the like as exemplified in FIG. 1.

〔Effect of the invention〕

According to the present invention described above, the metal material with the enamel insulating layer formed on its surface is cut into a shape suitable for the substrate to be manufactured, and then the enamel insulating layer is fired again. Even if a crank occurs in the insulating layer, it can be eliminated again, and as a result, poor insulation between the metal core and the conductor pattern due to the silver migration phenomenon can be prevented. Also,
This has the effect of eliminating the possibility of missing the hollow insulating layer due to the expansion of cracks.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a small motor equipped with an enameled insulated metal wiring board manufactured according to the present invention, Fig. 2 is a perspective view of the enameled insulated metal wiring board, and Fig. 3 is a reversal of the enameled insulated metal wiring board. 4th perspective view showing the state
This figure is a perspective view showing the state before the cutting process by pressing of the above enamel insulated metal wiring board, and FIG. 5 is a perspective view showing the state after the above enamel insulating metal wiring board has been refired after the cutting process. 10-Enameled insulated metal wiring board 10a-Metal core 10b-Enameled insulating layer 10c-Conductor pattern 2
0-Metal material patent applicant Sankyo Seiki Seisakusho Co., Ltd. rr5 ()

Claims (1)

[Claims] A process of uniformly firing and forming an enameled insulating layer on the surface of the metal material that will become the metal core, a process of cutting the metal material with the enameled insulating layer formed on the surface into a shape according to the enameled substrate to be manufactured, and 1. A method for producing an enameled insulating metal substrate, which comprises at least the step of forming a conductor pattern constituting a circuit on an insulating layer, and after the cutting step, the enameled insulating layer is fired again.