GB2311663A

GB2311663A - Conductive non-metallic spark plug connector element

Info

Publication number: GB2311663A
Application number: GB9705679A
Authority: GB
Inventors: Dirk Peier
Original assignee: BREMICKER AUTO ELEKTRIK
Current assignee: BREMICKER AUTO ELEKTRIK
Priority date: 1996-03-29
Filing date: 1997-03-19
Publication date: 1997-10-01
Also published as: GB9705679D0; DE19612508C2; ITMI970551A1; DE19612508A1; IT1290590B1; FR2746974A1

Description

2311663 CONNECTING PLUG The present invention relates to a connecting plug

for plugging onto an ignition plug, a heater plug or an ignition coil of an internal combustion engine, having an insulating body, an electrical connecting element, a connection part for an ignition cable and a contact part for a plug or coil, the connecting element, the connection part and the contact part being surrounded by the insulating body.

In the prior art, interference suppression plugs are known which comprise an interference suppression resistor having a resistance wire wound onto a carrier and a connection part and a contact part disposed at the ends of the carrier. This component is then enclosed in an insulating casing made of a thermosetting material or encapsulated by injection moulding. The interf erence suppression plug so formed is then inserted into a silicone sleeve for the purpose of electrical insulation and as protection against moisture.

The production complexity and, consequently, the cost expenditure for such plugs are appreciable.

Proceeding from this prior art, the aim of the present invention is to provide a connecting plug of the kind which can be manufactured inexpensively and with appreciable simplification.

Accordingly, the present invention provides a 2 connecting plug for plugging onto an ignition plug, a heater plug or an ignition coil of an internal combustion engine comprising an insulating body, an electrical connecting element, a connection part for an ignition cable and a contact part for a plug or coil, wherein the connecting element, the connection part and the contact part are surrounded by the insulating body, and at least one of the connecting element, the connection part or the contact part is formed by a high-voltage connecting means of electrically conductive polymer material, ceramic material or glass fusion material or a combination thereof.

In this connection, preferably, the insulating body is formed onto, in particular injected onto, the unit formed from connecting element, the connection part and the contact part.

Furthermore, at least one of the connection part and the contact part may be formed integrally with and of the same material as the connecting element.

In addition, the unit comprising the connection part, the contact part and the connecting element is preferably a moulded part, in particular an injectionmoulded part.

The design of the plug according to the present invention makes a very inexpensive implementation possible. In addition, manufacturing steps or.. assembly steps can be omitted in the fabrication of,the plug... The 3 electrical resistance necessary can be adjusted as desired by suitable material choice or by enriching the material with conductivity-increasing material, for example graphite. In particular, in the case of an integral design comprising a thermosetting material, a thermoplastic material or a ceramic, the separate manufacture of relatively expensive metal parts is no longer necessary, and the entire element comprising the connection part, the contact part and the connecting element can be moulded in one moulding step. In addition, with appropriate material selection, the occurrence of boundary layer problems between the internal elements and the external insulating body can be avoided.

In order to be able to utilize such a connecting plug as interference suppression element, at least one of the connection part, the contact part or the connecting element may have a tapered inductance or constricted inductance.

In this connection, the tapered inductance is preferably formed by an annular groove, wherein the cross-section of a central disc-shaped region defined by the annular groove is smaller than the cross-section of the connecting element.

In order to increase the inductance, a ferrite or other magnetic material can be incorporated in the tapered inductance zone or constricted inductance zone.

4 In addition, the conductive thermosetting material, thermoplastic material or ceramic material can be selected to have an ohmic resistance of from about 0 to about 100 Kiloohm.

Preferred embodiments of the present invention will now be described hereinbelow by way of example only with reference to the accompanying drawings, in which:

Figure 1 shows a longitudinal section of a connecting plug in accordance with a preferred embodiment of the present invention; and Figure 2 shows a longitudinal section of a connecting plug in the form of an interference suppression plug in accordance with another preferred embodiment of the present invention.

The connecting plug 1, which may be an interference suppression plug as shown in Figure 2, serves to plug onto the insulator of an ignition plug or a heater plug or onto the dome of an ignition coil of an internal combustion engine and connect those components to an ignition cable. For this purpose, the connecting plug 1, has an external insulating body 2 made of insulating material, preferably silicone. Disposed in the interior of the insulating body 2 is an electrical connecting element 3, a connection part 4 for an ignition cable 5, and a contact part 6 for connection to a plug or coil of an internal combustion engine. The connecting element 3, the connection part 4 and the contact part 6 are interconnected mechanically and electrically.

In the embodiment of Figure 1, the connecting element 3, the connection part 4 and the contact part 6 are integrally formed, for example injection-moulded from an electrically conductive thermoplastic material such as PPS (polyphenylene sulphide). Disposed on the outside around the insulating body 2 is a metallic screen 7, such as is known per se in the prior art.

The insulating body 2 extends appreciably beyond the connection part 4 and the contact part 6, so that an insulating and moisture-proof fixing of the ignition cable 5 or a corresponding connection to the plug or ignition coil is made possible.

In the embodiment of Figure 2. the connecting element 3, the connection part 4 and the contact part 6 are composed of a thermoplastic material or, alternatively, of an electrically conductive thermosetting material or ceramic material. The conductivity can be adjusted by adding suitable components to the raw material. For example, graphite can be incorporated in the basic material in an appropriate amount.

In order to incorporate an inductance in the part, tapered inductances or recessed inductances are provided in the embodiment of Figure 2. In this connection, the recessed inductances are provided in each case by an annular groove 8, wherein the cross section of the disc- 6 shaped region def ined by the annular groove is smaller than the cross section of the connecting element 3. In addition, a ferrite material can be incorporated in the tapered inductance zone or the constricted inductance zone to increase the inductance.

Preferably, a thermosetting material, a thermoplastic material or a ceramic material having an ohmic resistance of from 0 to about 100 Kiloohm is used as the production material for the connecting element 3, the connection part 4 and the contact part 6.

By virtue of the construction of the plug of the invention, it is possible to produce suitable connecting plugs, in particular interference suppression plugs, inexpensively. Steps can be omitted both in regard to the manufacture and also in regard to the assembly, and the electrical resistance of the plug can be adjusted almost as desired by suitable material selection. The use of expensive individual parts, in particular metal parts, for forming the connection part 4 or contact parts 6 can be dispensed with.

It will be understood that the present invention is not limited to the exemplary embodiment, but can be modified in many different ways within the scope of the invention as defined in the appended claims.

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Claims

Claims:

1 A connecting plug for plugging onto an ignition plug, a heater plug or an ignition coil of an internal combustion engine comprising an insulating body, an electrical connecting element, a connection part for an ignition cable and a contact part for a plug or coil, wherein the connecting element, the connection part and the contact part are surrounded by the insulating body, and at least one of the connecting element, the connection part or the contact part is formed by a highvoltage connecting means of electrically conductive polymer material, ceramic material or glass fusion material or a combination thereof.

2. A connecting plug according to claim 1, wherein the conductive polymer material comprises one of a thermosetting, a thermoplastic or an elastomeric material.

3. A connecting plug according to claim 1 or 2, wherein the insulating body is composed of an elastomeric material.

4. A connecting plug according to claim 3, wherein the insulating body is composed of silicone.

5. A connecting plug according to any foregoing claim, wherein the insulating body is formed onto the unit formed by the connecting element, the connection part and the contact part.

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6. A connecting plug according to any foregoing claim, wherein the insulating body is an injection moulded body.

7. A connecting plug according to any foregoing claim, wherein at least one of the connection part and the contact part is formed integrally with and of the same material as the connecting element.

8. A connecting plug according to claim 7, wherein the unit comprising the connection part, the contact part and the connecting element is a moulded part.

9. A connecting plug according to claim 8, wherein the moulded part is an injection moulded part.

10. A connecting plug according to any foregoing claim, wherein at least one of the connection part, the contact part or connecting element has a tapered inductance or constricted inductance.

11. A connecting plug according to claim 10, wherein the tapered inductance is formed by an annular groove, the cross-section of a discshaped central region defined by the annular groove being smaller than the cross-section of the connecting element.

12. A connecting plug according to claim 10, wherein a ferrite material or another magnetic material is incorporated in the tapered inductance zone or constricted inductance zone.

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13. A connecting plug according to claim 2, wherein the conductive thermosetting material, thermoplastic material or ceramic material has an ohmic resistance of from about 0 to about 100 Kiloohm.

14. A connecting plug for plugging onto an ignition plug, a heater plug or an ignition coil of an internal combustion engine substantially as hereinbefore described with reference to Figure 1 or Figure 2.