Ignition coil for internal combustion engine

Patent metadata

Field	Value
Publication number	US-10305258-B2
Application number	US-201615564876-A
Country	US
Kind code	B2
Filing date	Apr 7, 2016
Priority date	Apr 8, 2015
Publication date	May 28, 2019
Grant date	May 28, 2019

Abstract

In an ignition coil for an internal combustion engine, a spark plug is incorporated which has an insulator including an insulator head that has no corrugation. The ignition coil has a coil body part generating high voltage and a joint part, which holds therein a conducting member electrically connecting the coil body part and a spark plug. The joint part has a plug cap into which the insulator head of the spark plug is inserted and which is formed of an elastic member having a cylindrical shape. The plug cap has a close-contact part whose inner peripheral surface is closely brought into contact with an outer peripheral surface of the insulator. The close-contact part has a tip end-side close-contact part positioned at a tip end side with respect to a middle position in an axial direction, and a base end-side close-contact part positioned at a base end side with respect to the middle position. At least part of the base end-side close-contact part is provided with a strong strained force part that has strained force for fastening the insulator head, the strained force being stronger than strained force of all portions of the tip end-side close-contact part.

First claim

The invention claimed is:

1. An ignition coil for an internal combustion engine and configured to receive a spark plug that has an insulator including an insulator head that has no corrugation, the ignition coil comprising
a coil body part configured to generate a voltage sufficient to generate a spark, and
a joint part, which holds therein an electrical conductor electrically connected to the coil body part and configured to electrically connect to the spark plug, wherein
the joint part has a plug cap into which the insulator head of the spark plug is configured to be inserted and which is formed of an elastic member having a cylindrical shape,
the plug cap has a close-contact part with an inner peripheral surface that is configured to be closely brought into contact with an outer peripheral surface of the insulator,
the close-contact part has a tip end-side close-contact part positioned at a tip end side with respect to a middle position in an axial direction, and a base end-side close-contact part positioned at a base end side with respect to the middle position,
at least part of the base end-side close-contact part is provided with a strong strain force part that is configured to generate a strain force for fastening the insulator head, the strain force for fastening the insulator head being stronger than a strain force of all portions of the tip end-side close-contact part,
the tip end-side close-contact part has an internal diameter that is constant in the axial direction,
the close-contact part is configured to closely contact the outer peripheral surface of the insulator from a base end of the base end-side close-contact part to a tip end of the tip end-side close-contact part,
the strong strain force part includes an inner peripheral surface of the plug cap that is swelled inward so that a thickness thereof in a radial direction is larger than that of the tip end-side close-contact part when spark plug is not received in the ignition coil, and
an internal diameter of the close-contact part is constant along an axial direction.

Assignees

• Denso Corp

Inventors

• Hattori Kenji
• Doi Kaori
• Shibata Masamichi
• Miwa Tetsuya

Classifications

• F02P3/02

  having inductive energy storage, e.g. arrangements of induction coils {(ignition coils structurally combined with sparking plugs F02P13/00; constructional details of ignition coils H01F38/12)} · CPC title

• H01F38/12

  Ignition, e.g. for IC engines · CPC title

• F02P13/00

  Sparking plugs structurally combined with other parts of internal-combustion engines ({connection of ignition coil to spark plug connector F02P3/02;} with fuel injectors F02M57/06 {; spark plug connector per se H01T13/04 – H01T13/06; predominant aspects of sparking plug, see H01T13/40 – H01T13/44}) · CPC title

• H01T13/04 Primary

  Means providing electrical connection to sparking plugs · CPC title

• F02P15/00

  Electric spark ignition having characteristics not provided for in, or of interest apart from, groups F02P1/00 - F02P13/00 {and combined with layout of ignition circuits (not combined F02B, F02C, F02G, F02K)} · CPC title