JPH02228010A - Transformer - Google Patents

Abstract

PURPOSE:To obtain a transformer characterized by excellent heat resistance, suitability for mass production and excellent output characteristics by using a film made of polymethylpentene as an insulating member. CONSTITUTION:A transformer 1 has an approximately cylindrical shape and has the following parts: a case 2 wherein an ignition-plug mounting part 2a is provided at one end part, and the other end is opened; an I-type core 3; a secondary winding 4 which is wound around the outer surface of the core 3; a primary winding 5 which is wound around the outer surface of the winding 4; a cylindrical core 6 which is arranged around the outer surface of the primary winding 5; and bias magnets 7a and 7b which are arranged at both end parts of the core 3. Films 10 made of polymethylpentene are coaxially wound between the layers of the secondary winding 4 and the primary winding 5, between the secondary winding 4 and the outer surface of a bobbin 8 and between the primary winding 5 and the inner surface of the cylindrical core 6, respectively. The insulation between them is provided. In this way, the transformer characterized by excellent heat resistance, excellent output characteristics and suitability for mass production is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a transformer, and more particularly to a transformer suitable for supplying high voltage to a spark plug or the like of an internal combustion engine.

(Prior art) In general, in a transformer that has a large transformation ratio and generates high voltage, there is insulation between layers of the primary winding for low voltage input and secondary winding for high voltage generation, insulation between windings, and even insulation between each winding. It is necessary to give sufficient consideration to the insulation between the wire and the core. Furthermore, it is necessary to fully consider heat resistance.

Insulating members that provide insulation in such transformers have traditionally been made of insulating paper such as kraft paper, PET (polyethylene terephthalate) or PP (polypropylene).
A film made of polyphenylene sulfide or pps (polyphenylene sulfide) is used.

However, in the case of insulating paper, in order to increase the dielectric strength, the thickness must be increased, so in recent years, films have been increasingly used as insulating members.

When a PP film is used as an insulating member, PP
Due to its physical properties, this film has a problem in that its heat resistance characteristics deteriorate at temperatures above about 100'C.

Furthermore, when a PPS film is used as the insulating member, although it is superior to PET and PP films in terms of heat resistance, it has the drawback of being expensive and lacking in mass production.

Furthermore, both the above-mentioned PET and PPS films have a dielectric constant of 3.0 or more, which causes a problem of lowering the resonant frequency of the transformer and deteriorating the output voltage characteristics.

(Problems to be Solved by the Invention) The present invention has been made in view of the above circumstances, and aims to provide a transformer that has excellent heat resistance, is suitable for mass production, and can obtain good output characteristics. This is the purpose.

[Structure of the Invention] (Means for Solving the Problems) The transformer of the present invention comprises a multilayer primary winding and a secondary winding, a core that magnetically couples these two windings, and a core for magnetically coupling these two windings. The transformer has an insulating member that insulates between layers, between each winding, and between each winding and a core, using a polymethylpentene film as the insulating member.

(Function) According to the transformer having the above structure, a film made of polymethylpentene is used as an insulating member to insulate between the layers of the primary and secondary windings, between each winding, and between each winding and the core. Therefore, compared to the case where a film made of PET or PPS is used, the low dielectric constant causes a high resonance frequency and good output characteristics.

Additionally, it has higher heat resistance than PP film, so it can be used at high temperatures.

Furthermore, since polymethylpentene films are less expensive than PPS films, they are suitable for mass production.

(Example) An embodiment of the present invention will be described below with reference to FIG.

The transformer 1 shown in the figure is configured to supply a high voltage to a spark plug 2o, and has a substantially cylindrical shape with a spark plug mounting portion 2a at one end and an open end at the other end. A case 2, a ■-shaped core 3 built into the case 2, a multilayer secondary winding 4 made of relatively thin wire wound around the outer periphery of the core 3, and the secondary winding 4. A multilayer primary winding 5 made of comparatively thin wire is wound around the outer periphery of the secondary winding 5, a cylindrical core 6 is arranged around the outer periphery of the secondary winding 5, and bias magnets are arranged at both ends of the core 3. 7a.

7b.

Between each layer of the secondary winding 4 and the secondary winding 5, between the secondary winding 4 and the outer periphery of the bobbin 8 described later, and between the secondary winding 5 and the inner peripheral surface of the cylindrical core 6. A film 10 made of polymethylpentene as an insulating member is concentrically wound between the two to provide insulation between the two.

The core 3 is disposed at the center of the case 2 along its length, and a cylindrical first bobbin 8 is attached to the outer periphery of the core 3.

The bobbin 8 is formed to have a length that projects laterally from both ends of the core 3, and bias magnets 7a and 7b are attached inside each end of the bobbin 8 in close contact with the core 3.

Further, a support member 9 made of an insulator is fixed to the end of the bobbin 8 on the bias magnet 7a side, and this support member 9 allows the connector 21 for the spark plug 20 to face the opening of the spark plug mounting portion 2a. It is designed to support the state.

The cylindrical core 6 is made of a non-oriented silicon steel plate (about 0.1 mm thick) containing about 6.5 wt% silicon.
It is formed by winding it around the outer periphery of the next winding 5 about two to three times.

In FIG. 1, reference numeral 11 indicates a synthetic resin filler filled in the case 2.

Here, the physical properties of the film 10 will be mentioned. Table 1 below shows a comparison of the temperature characteristics and dielectric constants of polymethylbenzone, PEP, PPS, and PP.

Table 1 Next, the action of the transformer l having the above configuration is shown in the film 10.
The effect will be explained mainly with reference to Table 1.

Since this transformer 1 uses the film 10 having the above-described structure as an insulating member, the continuous use temperature is higher than when a PP film is used, and the transformer 1 is superior to the conventional example in terms of heat resistance.

Furthermore, since the film 10 of this example has a smaller dielectric constant than films made of PET or PPS, the resonant frequency of the transformer 1 itself can be made higher than that of the conventional example.

That is, the output voltage output from the secondary winding 4 of the transformer 1 of this embodiment can obtain a preset peak value of -40 (kV), for example, as shown in FIG.

On the other hand, in a transformer using a film made of PET or PPS, the dielectric constant is higher than that of the film 10, and as shown by the dotted line in FIG.
kV) is difficult to obtain.

In this way, the transformer 1 of this embodiment has better output characteristics than the conventional example.

Furthermore, since polymethylpentene is cheaper than PPS, the transformer 1 of this embodiment is suitable for mass production.

Further, since the film 10 is more flexible than films made of PET or PPS, when manufacturing the transformer 1, the secondary winding 4. - Another advantage is that the winding work for the next winding 5 is easy.

Incidentally, this problem can be solved by subjecting the film 10 made of polymethylpentene to corona treatment to roughen its surface and increase its adhesion to the filler 11.

The present invention can be modified in various ways other than the embodiments described above.

For example, in the above-mentioned embodiment, a case has been described in which the transformer functions as a high-voltage transformer for a spark plug, that is, an ignition transformer, but it is also applicable as a flyback transformer for a television.

[Effects of the Invention] According to the present invention detailed above, by using a polymethylpentene film as an insulating member, it is possible to provide a transformer that has excellent heat resistance, good output characteristics, and is suitable for mass production. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the transformer of the present invention, and FIG.
This figure is a perspective view showing the winding state of the film on the secondary winding side of the transformer shown in FIG. 1, and FIG. 3 is a waveform diagram showing the output voltage waveform of the transformer. DESCRIPTION OF SYMBOLS 1...Transformer, 3...Core, 4...Secondary winding, 5...-Secondary winding, 10...Film.

Claims (1)

[Claims] A multi-layered primary winding and a secondary winding, a core that magnetically couples these two windings, and an insulating member that insulates between the layers of each winding, between each winding, and between each winding and the core. A transformer characterized in that a polymethylpentene film is used as the insulating member.