Method of manufacturing a molded fuel injector

• US 5,185,919 A
• Filed: 05/14/1992
• Issued: 02/16/1993
• Est. Priority Date: 11/19/1990
• Status: Expired due to Term

• Current Assignee: Mid-America Commercialization Corporation
• Original Assignee: Ford Motor Company
• Inventors: Hickey, John C.
• Primary Examiner(s): Hall, Carl E.
• Application Number:
  US07/882,786
• Time in Patent Office: 278 Days
• Field of Search: 29/602.1, 29/606, 264/272.19, 251/129.15, 251/129.21, 239/585.2, 239/585.4, 239/585.5, 239/600, 123/456, 123/470, 123/468, 123/466
• US Class Current: 29/602.1
• CPC Class Codes: B29C 45/14065 Positioning or centering articles in the mould
• CPC Class Codes: B29C 45/14639 for obtaining an insulating effect, e.g. for electrical components
• CPC Class Codes: F02M 51/0614 characterised by arrangement of electromagnets or fixed armature
• CPC Class Codes: F02M 51/0678 all portions having fuel passages, e.g. flats, grooves, diameter reductions
• CPC Class Codes: F02M 61/166 Selection of particular materials
• CPC Class Codes: F02M 61/168 Assembling; Disassembling; Manufacturing; Adjusting
• CPC Class Codes: F02M 69/465 of fuel rails
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor

Abstract

A fuel injector having major components formed by an injection molding process. A coil bobbin assembly is positioned within a magnetic permeable core. An injection molding process provides a plastic housing with the magnetic core and coil bobbin assembly hermetically sealed therein. The molding process also provides a fuel passageway through, and hermetically sealed from, the magnetic core and coil bobbin assembly.

Claims

1. A method for forming a fuel injector, comprising the steps of:

positioning an electric coil assembly adjacent to a magnetic core which is comprised of a magnetic permeable material for receiving magnetic energy from said coil assembly;

injection molding plastic around both said magnetic core and said coil assembly to totally surround and hermetically seal said coil assembly and permanently position said coil assembly adjacent to said magnetic core, said injection molding step also forming a cavity concentric to said coil assembly;

slidably inserting an armature into said cavity, said armature comprised of a magnetic permeable material for magnetically coupling to said magnetic core; and

coupling a needle and seat valve to said armature for controlling fuel flow.

2. The method for forming a fuel injector recited in claim 1 further comprising the steps of:

inserting a removable pin within said cavity concentric to said coil assembly; and

positioning said pin and said coil assembly and said magnetic core in a recess of a mold.

3. The method for forming a fuel injector recited in claim 2 wherein said step of coupling a needle and seat valve further comprises a step of coupling a silicon etched nozzle to said needle and seat valve.

4. A method for forming a fuel injector for controlling fuel from a fuel supply, comprising the steps of:

inserting an electric coil assembly within a magnetic core and positioning both within a separable mold wherein said electric coil assembly includes a wire wound on a bobbin having a pair of electrical contacts extending therefrom;

inserting a first removable pin into an opening concentrically formed in both said magnetic core and said coil assembly;

inserting a second removable pin to encapsulate said pair of electrical contacts;

injecting plastic into said mold for hermetically sealing said coil assembly within said magnetic core and also forming a fuel injector housing surrounding said coil assembly and said magnetic core;

removing said first pin to define an electrical connection for said pair of electrical contacts which is external to said housing and sealed from said fuel passageway;

removing said separable mold to define an integrally formed fuel injector housing with a fuel passageway, magnetic core, and hermetically sealed electric coil assembly positioned therein;

inserting an armature comprised of a magnetic permeable material into said fuel passageway; and

coupling a needle and seat valve to said armature and to said fuel passageway for controlling fuel flow.

5. The method recited in claim 4 further comprising the steps of:

inserting a third removable pin into said mold and biased against said magnetic core opposite said first removable pin; and

removing said third removable pin after said injection molding step to define a neck integrally formed with said housing having an extended fuel passageway therein.