Fuel-injection metering device, fuel-injection nozzle, mould for producing a fuel-injection metering device and method for producing a fuel-injection metering device

Abstract

The present application concerns a fuel-injection metering device for a motor vehicle. The fuel-injection device include a main body with at least one through-hole, whereby the main body forms a valve seat on its inner face that is provided to interact with a valve body, whereby the inner face of the main body is electrochemically machined. The application also concerns a mould, a production method, and a fuel-injection nozzle.

Claims

1. Mould for producing a fuel-injection metering device, with an electrically chargeable cathode, whereby the cathode exhibits at one end an electrically insulating layer through which an engagement section of the cathode protrudes, characterized in that, the engagement section is surrounded by segment-like insulation sections running in an axial direction, between which active areas of the cathode are uncovered.

2. Mould according to claim 1, characterized in that there is at least one electrolyte fluid guidance groove on the surface of the insulation layer, and/or at least one electrolyte fluid guidance channel runs through the material of the insulation layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is also explained in more detail as follows by means of a drawing. The drawing features different embodiments. The following are shown:

(2) FIG. 1 shows a fuel-injection metering device according to the invention in installed state in a fuel-injection nozzle depicted in longitudinal cross-section,

(3) FIG. 2 shows a top view only of the fuel-injection metering device from the fuel feed side,

(4) FIG. 3 shows a longitudinal section along line Ill from FIG. 2 through the fuel-injection metering device shown in that figure,

(5) FIG. 4 shows an enlargement of the area IV from FIG. 3,

(6) FIG. 5 shows a cross-section along line V through the fuel-injection metering device from FIG. 3,

(7) FIGS. 6a and 6b show perspective views of a mould according to the invention for producing a fuel-injection metering device according to the invention,

(8) FIG. 7 shows a cross-section through an engagement section of a mould configuration of FIGS. 6a and 6b acting as a cathode,

(9) FIG. 8 shows a variant of the embodiment from FIG. 7 of an engagement section of a mould configuration acting as a cathode,

(10) FIG. 9 shows the engagement section from FIG. 7 without insulating segments on the outer face between wing-like active elements,

(11) FIG. 10 shows the engagement section from FIG. 8 without insulating segments, similar to the depiction in FIG. 9,

(12) FIG. 11 shows an initial depiction of a method for producing a fuel-injection metering device, and

(13) FIG. 12 shows a variant of a method for producing a fuel-injection metering device.

DETAILED DESCRIPTION

(14) The figures are diagrammatic in nature only and serve solely to explain the invention. Identical elements bear the same reference numerals. Features of the various embodiments can be interchanged. A specific feature of one embodiment can therefore be realized in another embodiment.

(15) FIG. 1 shows a section of a fuel-injection nozzle nearest to a combustion chamber. This fuel-injection nozzle 1 can be activated by an actuator not shown which can comprise a solenoid, a magnetic cup, an overmould, connector pins, conductor barrels, support discs, O-rings, clamping sleeves, adjusting sleeves, internal poles, covers, stop rings and similar components.

(16) The fuel-injection nozzle 1 also comprises a valve sleeve 2 on which a sealing element 3 such as a sealing ring is mounted. An activation element such as a needle 4 can be positioned inside the valve sleeve 2. The needle 4 acts as a tappet. A valve body 5 is positioned at the end of the needle 4 which is closest to the combustion power. The valve body 5 is configured as a sphere 6 or is sphere-like. The valve body 5 is positioned inside a fuel-injection metering device 7. Here, the fuel-injection metering device 7 forms a valve seat 8 on the inner face 9 of a main body 10. The main body 10 is inserted in the valve sleeve 2, preferably tightly fitted and additionally or alternatively secured in a positive-locking manner. The main body 10 can essentially be attached to the valve sleeve 2 in a firmly bonded, force-fitting or positive-locking manner.

(17) The main body 10 in cup-like configuration is also shown in FIG. 2 in enlarged form. It comprises a circumferential wall 11 which is closed at one end by a base 12.

(18) The integral configuration of the base 12 with the wall 11 can be clearly seen in FIG. 3.

(19) Returning to FIG. 2, attention is drawn to five longitudinal grooves 13 which can also be designated as pockets. The longitudinal grooves 13 have a concave, evenly rounded shape. They are separated from each other by ridges 14. At each side of a ridge 14 there is an edge 15 oriented in an axial direction.

(20) The edges 15 are blunted/rounded in configuration, in particular with a radius of 300-500 μm. Radius, measurements of approximately 100 μm to 800 μm, in particular approximately 600 μm, 650 μm, 700 μm and 750 μm are especially preferable. The longitudinal grooves 13, the curvatures of the edges 15 and the shape of the recess 16 formed by them are defined or solely and/or conclusively caused by means of an electrochemical machining method.

(21) As can also be clearly seen in FIG. 3, a central or centric depression 17 is configured. While the depression 17 is on the inner face 9, there is on the outer face, complementary to the depression 17, a protrusion 18 in the form of a dome/ball shape or a convexity/protuberance.

(22) It can be clearly seen in FIG. 3 that the longitudinal grooves 13 do not extend over the entire length of the inner face 9. In this way, the longitudinal grooves 13 run between a hollow-cylindrical wall section 19 and a chamfered area 20 up to a transition area 21 close to the base. The relevant bevel angle for the chamfered area 20 at which the longitudinal grooves/pockets 13 are (solely) positioned is approximately 5° to 10°.

(23) This angle is designated in FIG. 4 as a. FIG. 5 also clearly shows the regular alternation between ridges 14 and longitudinal grooves 13 as well as the roundness of the edges/longitudinal edges 15 in the area of the ridges 14.

(24) FIGS. 6a and 6b show the tip of a mould 22 according to the invention. The mould 22 exhibits a basic body 23, for example made of brass. Towards its tip, i.e. for the purpose of protrusion into the main body 10 when inserted into the later, the basic body 23 has a reduced diameter and is designated at this point as the engagement section 24: The engagement section 24 exhibits a hollow core 25 made of the same material as the basic body 23, which is preferably brass. On the outer face, the engagement section 24 is surrounded by segment-like insulation sections 26. The segment-like insulation sections 26 are chamfered or flattened towards the distal end of the engagement section 24. A radial outer end face 27 of active elements 28 protruding from the core 25 moves to the surface between the segment-like engagement sections 26. Leading away from the end faces 27 in a radial direction, electrolyte fluid guidance grooves 30 are provided in a ring 29. The ring 29 is structured out of insulating material, thereby acting as an insulation layer 31. The ring 29 is at the end of the larger diameter of the basic body 23 that serves as a cathode. The basic body 23, which ultimately forms the core 25 of the engagement section 24, is electrically chargeable and as such acts as a cathode 32.

(25) This cathode 32 is also shown in FIG. 6b.

(26) FIG. 7 shows a cross-section of an engagement section 24. Here, the active elements 28 protrude like wings from a tube-like configuration of the core 25. The core 25 in this case has a wall thickness which is relatively thin, for example between 0.2 and 0.3 mm. The integral active elements 28 then transport electric current to their end faces 27, whereby the current occurring at the end faces 27 results in removal of material on the inner face 9 of the main body 10, when the cathode 32 is inside or is inserted in the recess/(pocket) hole 16. The insulation sections 26 are then always positioned between two integral active elements connected with the core 25.

(27) This is also the case in the embodiment shown in FIG. 8, although in this case the shape of the wings/active elements 28 differs from the embodiment shown in FIG. 7. The cross-section of the core 25 with active elements 28 is more star-shaped/poinsettia-like in this case, such that the active elements 28 widen in the direction of the core 25.

(28) FIGS. 9 and 10 show the cathode materials of the engagement sections 24 in cross section. Inside the cathode 32 during operation, an electrolyte fluid flows either into the main body 10 of the fuel-injection metering device 7 or out of it. This can be seen especially clearly in FIGS. 11 and 12. The electrolyte flow is indicated by means of arrows 33. In the embodiments shown in FIGS. 11 and 12, electrolyte fluid flows through the interior of the cathode 32 into the interior of the main body 10 and then either (see FIG. 11) out through an electrolyte fluid groove 30 or out through an electrolyte fluid channel 34 (see FIG. 12). However, it is much more advantageous if the direction of fluid flow is reversed.

(29) In the embodiment according to FIG. 11, a discolouration on the surface of the main body 10 facing the insulation layer 31 is shown in position 35.

(30) It should be apparent that the foregoing relates only to the preferred embodiments of the present application and the resultant patent. Numerous changes and modification may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and the equivalents thereof.

LIST OF REFERENCE NUMERALS

(31) 1 Fuel-injection nozzle 2 Valve sleeve 3 Sealing element 4 Needle 5 Valve body 6 Sphere 7 Fuel-injection metering device 8 Valve seat 9 Inner face 10 Main body 11 Wall 12 Base 13 Longitudinal groove/pocket 14 Ridge 15 Edge/longitudinal edge 16 Recess/(pocket) hole 17 Depression 18 Protrusion 19 Hollow-cylindrical wall section 20 Chamfered area 21 Transition area 22 Mould 23 Basic body 24 Engagement section 25 Core 26 Segment-like insulation section 27 End face 28 Active element 29 Ring 30 Electrolyte fluid groove 31 Insulation layer 32 Cathode 33 Electrolyte fluid flow 34 Electrolyte fluid channel 35 Discolouration