Claims:We Claim

1. A magnet assembly (200) of a fuel injector (100), comprising at least :
- a magnet core (230);
- a magnet sleeve (205a) accommodating the magnet core (230) connected to a backflow tube (205b);
- a magnet armature (210), which cooperates with the magnet core (230), and is arranged in a longitudinally moveable manner along a longitudinal axis of the magnet sleeve (205a);
characterized in that, said magnet sleeve (205a) is integrated with said backflow tube (205b) into a single component (205).

2. The magnet assembly as claimed in claim 1, wherein one end of said magnet sleeve (205) in proximity with said magnet armature (210) has at least two retaining screws (220) on the inner surface of said magnet sleeve.

3. A fuel injector (100), said fuel injector (100) comprising at least :
- a backflow tube (205b) and a magnet assembly (200), said magnet assembly (200) comprising a magnet core (230); a magnet sleeve (205a) accommodating the magnet core (230); and a magnet armature (210), which cooperates with the magnet core (230), and is arranged in a longitudinally moveable manner along a longitudinal axis of the magnet sleeve (205a), characterized in that, said magnet sleeve (205a) is integrated with said backflow tube (205b) into a single component (205).
, Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention

[0001]This invention relates to a magnet assembly for a fuel injector and a fuel injector thereof.

Background of the invention

[0002] Figure 1 is a representative illustration of a fuel injector known in the state of the art. A person skilled in art would be aware that many version of fuel injectors are already known. However, some basic components in a fuel injector are always present. Among other basic components of any fuel injector known in the state of the art, the magnet assembly is one of them. With regard to this disclosure we will specifically focus on the magnet assembly components.

[0003]The invention relates to a magnet assembly according to the preamble of claim 1. Furthermore, the invention relates to a fuel injector using a magnet assembly according to the invention.
[0004]A magnet assembly according to the preamble of claim 1 is known from DE102009001706A1 of the Applicant. The known magnet assembly has a magnet core with a magnet coil embedded in the magnet core, wherein the magnet core is radially surrounded by a magnet sleeve, which serves for the axial positioning or fixing of the magnet core within an injector. For this purpose, the magnet sleeve on a 10 radially inwardly projecting retaining section in the form of a retaining flange, which rests with the interposition of a residual air gap disc on a front face of the magnet core. The residual air gap disk in turn acts in an axial end position of a magnet armature, which is arranged longitudinally movably within the injector, with a (plane) front face of the magnet armature, against which the front face can abut. The magnet sleeve is joined at one end with a backflow connector which facilitates the return flow of fuel from the injector to the fuel tank. A disadvantage of such a construction is that the production and assembly costs of such a magnet assembly and thus also a fuel injector having such a magnet assembly are relatively high due to the separate components.

Brief description of the accompanying drawings

[0005] Figure 1 is a representative illustration of a fuel injector (100) and consequently a magnet assembly (200) for a fuel injector (100) known in the state of the art.

[0006] Figure 2 illustrates a magnet assembly (200) of a fuel injector (100) in accordance with this disclosure.

Detailed description of the invention

[0008] Figure 2 illustrates a magnet assembly (200) of a fuel injector (100) in accordance with this disclosure. The magnet assembly (200) comprises a magnet core (230), which has a radially encircling, annular receiving space for receiving a magnet coil (235) at one front face.
[0009]The magnet core (230) is radially surrounded by a magnet sleeve (205a), which is braced axially in the direction of the component via a threaded connection and a union nut, not shown in detail. The magnet sleeve (205a) is preferably made of a non-magnet material. The magnet sleeve (205a) has a flange-like retaining section (215) projecting radially in the direction of the longitudinal axis of the magnet core (230).
[0010]The fuel injector (100) also has a backflow tube (205b) which makes its way towards the magnet sleeve (205a). According to the disclosure, the backflow tube (205b) and the magnet sleeve (205a) are integrated together to form a unified magnet sleeve (205).

[0011] The lower end of the magnet sleeve contains at least two retaining screws (220) right on top of the said flange (215) like retaining section of the magnet sleeve (205). Said retaining screws (220) help to keep the magnet core (230) in position.

[0012]The retaining screws (220) are held in position with the help of external threads (225) being done on them. Said retaining screws (220) are then screwed in place into the internal threads (225) done on the inner surface of said magnet sleeve (205).

[0013]The advantage of said unified magnetic sleeve (205) is that it reduces the number of components, viz. separate backflow tube (205b) and separate magnet sleeve (205a), and thereby reduces the cost of manufacture. It also eliminates the need for Residual Air Gap shims (215 of Figure 1) for the magnet assembly (200).

[0014]It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to magnet assembly of fuel injector are envisaged and form a part of this invention. The scope of the invention is only limited by the claims.