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US 2010/0133252 A1Published application
Glow plug and method for manufacturing the same
AssigneeNgk Spark Plug Co., Ltd.
InventorHaruhiko Abe
Life of this patent
Estimating the term…
Abstract
The present invention provides a glow plug capable of preventing a deformation or eccentricity of the coil, thereby improving a durability of the coil and preventing a variation in temperature-rising characteristic. Also, the present invention provides a method for manufacturing the glow plug.
Claims9
A glow plug, comprising:
- an axially extending cylindrical sheath tube including a closed front end;
- a coil made of a resistance wire, disposed within said sheath tube, extending along the axis of the sheath tube and joined to a front end of the sheath tube;
- and
- insulating powder filled in the sheath tube,
- wherein the glow plug is formed through a swaging step,
- wherein a rod-like insulator made of an insulating material is inserted in the coil prior to the swaging step,
- wherein a thin portion having a diameter smaller than an outer diameter of a general portion of the insulator is formed on the front end side of the insulator, said thin portion being inserted into a taper-shaped reduced diameter portion formed at the front end side of the coil, and
- wherein a front end portion of the insulator is disposed at a front edge position in a predetermined section in the axial direction where the swaging step is conducted.
5 more elements
(canceled)
(canceled)
A method for manufacturing a glow plug, comprising:
- disposing a coil made of a resistance wire along an axis of a cylindrical sheath tube that extends in an axial direction, said coil having a taper-shaped reduced diameter portion formed in a vicinity of the front end of the coil;
- joining a front end of the coil to a front end portion of the sheath tube while closing the front end of the sheath tube;
- inserting a rod-like insulator made of an insulating material into the coil, said insulator having a thin portion, which is formed on the front end side of the insulator, said thin portion having a diameter smaller than an outer diameter of a general portion of the insulator, said thin portion of said insulator being inserted in said taper-shaped reduced diameter portion formed in a vicinity of the front end of the coil;
- filling the sheath tube with an insulating powder;
- and
- swaging the sheath tube,
- wherein, in the swaging step, a front edge position in a predetermined section in the axial direction where the swaging step is conducted is disposed at the same position as a front end portion of the insulator or at a rearward position with respect to the front end portion of the insulator.
4 more elements
Dependencies are inferred from the claim text.