Armature for a fuel injector

• US 9,309,847 B2
• Filed: 06/11/2012
• Issued: 04/12/2016
• Est. Priority Date: 08/09/2011
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schumacher, Matthias, Burghardt, Andreas, Rager, Jochen
• Primary Examiner(s): Talpalatski, Alexander
• Application Number:
  US14/237,704
• Publication Number:
  US 20140319392A1
• Time in Patent Office: 1,401 Days
• Field of Search: 335/279
• US Class Current: 1/1
• CPC Class Codes: F02D 19/0686 Injectors
• CPC Class Codes: F02D 19/084 Blends of gasoline and alcohols, e.g. E85
• CPC Class Codes: F02M 2200/02 Fuel-injection apparatus having means for reducing wear
• CPC Class Codes: F02M 2200/08 Fuel-injection apparatus having special means for influencing magnetic flux, e.g. for shielding or guiding magnetic flux
• CPC Class Codes: F02M 2200/8046 the manufacture involving injection moulding, e.g. of plastic or metal
• CPC Class Codes: F02M 2200/956 Ethanol
• CPC Class Codes: F02M 51/0664 having a cylindrically or partly cylindrically shaped armature, e.g. entering the winding; having a plate-shaped or undulated armature entering the winding
• CPC Class Codes: H01F 2007/086 Structural details of the armature
• CPC Class Codes: H01F 7/081 Magnetic constructions
• CPC Class Codes: H01F 7/129 of armatures
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

An armature for an injector including at least one magnetic region and at least one non-magnetic region, the armature being developed as a one-piece component, the magnetic and non-magnetic regions being integrally connected to each other by a two-component powder injection molding process, and the magnetic region being completely enclosed by the non-magnetic region.

Claims

1. An armature for an injector, comprising:

at least one magnetic region; and

at least one non-magnetic region, wherein;

the armature is configured as a one-piece component,

the magnetic and non-magnetic regions are integrally connected to each other as a two-component powder injection molding part, and

the magnetic region is completely enclosed by the non-magnetic region;

wherein the armature has an annular shape with a feed-through opening,

wherein the non-magnetic region includes a first axial end face section, a second axial and face section, an inner circumferential section, and an outer circumferential section,

wherein the first axial end face section faces an inner pole, and

wherein the outer circumferential section has a lesser thickness than a thickness of the second axial end face section and a thickness of the inner circumferential section.

3. The armature as recited in claim 1, wherein the inner circumferential section has a greater thickness than the thickness of the outer circumferential section and than the thickness of the second axial end face section.

4. The armature as recited in claim 1, wherein the armature forms a stop on at least one of a first and a second armature end face.

5. The armature as recited in claim 1, wherein:

the magnetic region is configured from a magnetic material having a high saturation induction, and

the non-magnetic region is configured from one of a ceramic material and a hard metal.

6. The armature as recited in claim 1, wherein the non-magnetic region is configured from a fuel-resistant material.

7. The armature as recited in claim 1, wherein the non-magnetic region is configured from a wear-resistant material.

8. The armature as recited in claim 1, wherein the magnetic region makes up 85 to 95% of the total weight of the armature, and the non-magnetic region 5 to 15% of the total weight of the armature.

9. The armature as recited in claim 1, wherein the armature forms a stop on at least one of a first and a second armature end face, wherein the magnetic region is configured from a magnetic material having a high saturation induction, and wherein the non-magnetic region is configured from one of a ceramic material and a hard metal.

10. The armature as recited in claim 1, wherein the armature forms a stop on at least one of a first and a second armature end face, and wherein the non-magnetic region is configured from a fuel-resistant material.

11. The armature as recited in claim 1, wherein the armature forms a stop on at least one of a first and a second armature end face, and wherein the non-magnetic region is configured from a wear-resistant material.

12. The armature as recited in claim 11, wherein the magnetic region makes up 85 to 95% of the total weight of the armature, and the non-magnetic region 5 to 15% of the total weight of the armature.

13. The armature as recited in claim 9, wherein the magnetic region makes up 85 to 95% of the total weight of the armature, and the non-magnetic region 5 to 15% of the total weight of the armature.

14. The armature as recited in claim 10, wherein the magnetic region makes up 85 to 95% of the total weight of the armature, and the non-magnetic region 5 to 15% of the total weight of the armature.

2. An armature for an injector comprising:

at least one magnetic region; and

at least one non-magnetic region, wherein;

the armature is developed as a one-piece component,

the magnetic and non-magnetic regions are integrally connected to each other as a two-component powder injection molding part, and

the magnetic region is completely enclosed by the non-magnetic region;

wherein the armature has an annular shape with a feed-through opening,

wherein the non-magnetic region includes a first axial end face section, a second axial and face section, an inner circumferential section, and an outer circumferential section,

wherein the first axial end face section faces an inner pole, and

wherein a thickness of the first axial end face section and a thickness of the outer circumferential section are identical.

15. A fuel injector, comprising:

a coil;

a valve sleeve;

a housing attached to an outer side of the valve sleeve, wherein the coil is situated within the housing;

an inner pole; and

an armature, including at least one magnetic region, and at least one non-magnetic region, wherein the inner pole and the armature are disposed in an interior of the valve sleeve along a center axis, and wherein;

the armature is configured as a one-piece component,

the magnetic and non-magnetic regions are integrally connected to each other as a two-component powder injected molded part, and

the magnetic region is completely enclosed by the non-magnetic region.

16. The fuel injector as recited in claim 15, wherein:

the armature has an annular shape with a feed-through opening,

the non-magnetic region includes a first axial end face section, a second axial and face section, an inner circumferential section, and an outer circumferential section,

the first axial end face section faces the inner pole, and

the outer circumferential section has a lesser thickness than a thickness of the second axial end face section and a thickness of the inner circumferential section.

17. The fuel injector as recited in claim 15, wherein:

the armature has an annular shape with a feed-through opening,

the non-magnetic region includes a first axial end face section, a second axial and face section, an inner circumferential section, and an outer circumferential section,

the first axial end face section faces the inner pole, and

a thickness of the first axial end face section and a thickness of the outer circumferential section are identical.

18. The fuel injector as recited in claim 15, wherein the armature forms a stop on at least one of a first and a second armature end face, wherein the magnetic region is configured from a magnetic material having a high saturation induction, and wherein the non-magnetic region is configured from one of a ceramic material and a hard metal.

19. The fuel injector as recited in claim 15, wherein the armature forms a stop on at least one of a first and a second armature end face, and wherein the non-magnetic region is configured from a fuel-resistant material.

20. The fuel injector as recited in claim 15, wherein the armature forms a stop on at least one of a first and a second armature end face, and wherein the non-magnetic region is configured from a wear-resistant material.

21. The fuel injector as recited in claim 20, wherein the magnetic region makes up 85 to 95% of the total weight of the armature, and the non-magnetic region 5 to 15% of the total weight of the armature.

22. The fuel injector as recited in claim 18, wherein the magnetic region makes up 85 to 95% of the total weight of the armature, and the non-magnetic region 5 to 15% of the total weight of the armature.

23. The fuel injector as recited in claim 19, wherein the magnetic region makes up 85 to 95% of the total weight of the armature, and the non-magnetic region 5 to 15% of the total weight of the armature.

24. A method for making an armature for a fuel injector, the method comprising:

providing a first armature part having a magnetic region;

providing a second armature part having a non-magnetic region, wherein the second armature part is arranged so that the non-magnetic region is completely enclosed by the non-magnetic region; and

integrally connecting the first armature part and the second armature part to each other by a powder injection molding process, so as to form the first and second armature parts into the armature which is a two-component powder injection molding part, wherein the armature has a feed-through opening for receiving a valve needle.

25. The method of claim 24, wherein the first armature part having the magnetic region is made of a magnetic material having a high saturation induction at a low electrical conductivity, and wherein the second armature part having the non-magnetic region is made from a ceramic material or a hard metal.

26. The method as recited in claim 24, wherein:

the armature has an annular shape with the feed-through opening,

the non-magnetic region includes a first axial end face section, a second axial and face section, an inner circumferential section, and an outer circumferential section,

the first axial end face section faces an inner pole, and

the outer circumferential section has a lesser thickness than a thickness of the second axial end face section and a thickness of the inner circumferential section.

27. The method as recited in claim 24, wherein:

the armature has an annular shape with the feed-through opening,

the non-magnetic region includes a first axial end face section, a second axial and face section, an inner circumferential section, and an outer circumferential section,

the first axial end face section faces an inner pole, and

a thickness of the first axial end face section and a thickness of the outer circumferential section are identical.