EP1797315B1 - Retainer for a fuel injection device - Google Patents

Description

State of the art

The invention is based on a hold-down device for a fuel injection device

Hold-downs with a flat base element are for example made of DE 101 52 421 A , of the US 5,970,953A ( FIG. 3 ) and the EP 1 544 455A (Published on 22.06.2005).

It is already out of the DE 29 26 490 A1 a fastening device for a fuel injection valve for attachment to a suction tube, in which the axial fixation of the fuel injection valve on the fuel distributor line or on a plug-in nipple by a fastener, which is designed as a U-shaped securing clip provided with two resiliently resilient legs is. The securing clip engages in the mounted state by corresponding recesses of the plug-in nipple and can be latched into a recess formed as an annular groove in a connecting piece of the fuel injection valve. The axial clearance between the recesses and the securing clip as well as between the annular groove and the securing clip should be kept small in order to achieve an exact fixation of the fuel injection valve without tension of the seal.

A disadvantage of the DE 29 26 490 A1 known fastening device is in particular the bracing effect of the various support parts the fuel injector. The force flow generated in the fuel injection valve leads to deformations and thus to changes in the stroke of the valve needle to jamming and to a pressure or bending load of the housing parts, which are generally thin-walled and welded together at several points. In addition, each fastening measure leads, for example by a support collar to increase the radial extent of the fuel injection valve and thus to an increased space requirement during installation.

It is already known from the DE 101 08 193 A1 a fixing device for mutually fixing a fuel injection valve in a cylinder head of an internal combustion engine and the fuel injection valve to a fuel distribution line. The fastening device comprises a sleeve which is clamped between a shoulder of the fuel rail and a shoulder of the fuel injection valve and is formed of an elastic material. Due to its tubular structure, the sleeve can transfer the hold-down forces to the fuel injector only to a limited extent effectively. The claimed by the shoulders of the fuel injector and fuel rail surfaces of serving as hold down sleeve represent the manufacturing edges resulting in the production of the blank of the sleeve cutting edges.

Advantages of the invention

The hold-down device according to the invention for a fuel injection device with the characterizing features of claim 1 has the advantage that it has a particularly simple design, is very simple and inexpensive to produce and still a very effective holddown of a fuel injector in a receiving bore of a cylinder head or an intake pipe is achieved. With conventional manufacturing processes, such as stamping, eroding or laser cutting, blanks for the subsequent hold-down can be removed from sheets of spring steel or stainless steel and bent into numerous, quite complex desired shapes.

With the hold-down device according to the invention without means for Verdrehfixierung a more accurate alignment of the fuel injector over known holddowns with integrated Verdrehfixierungen is possible, since the component tolerances of the hold-down for Verdrehfixierung omitted by the inventive design. The hold-down device can also compensate for larger axial tolerances than is possible with known hold-downs. Above all, in connection with the fuel injection device, which has a simple Verdrehfixierung, the above-mentioned advantages.

The measures listed in the dependent claims advantageous refinements and improvements of the claim 1 hold-down are possible.

It is advantageous to carry out the hold-down as a stamped and bent part and shape and obstruct in a fuel injector that the stress of bending stress surfaces of the inclined portions and abutment portions of the blank perpendicular to the cutting edges, the release of the blank for the Hold-downs from the corresponding sheet arise. In this way, the permanent load capacity of the stressed portions of the hold-down bracket of the hold-down can be increased and achieve an optimum hold-down force on the fuel injection valve for secure fixation in the receiving bore.

It is particularly advantageous to provide the hold-down in the circumferential direction with an open area in such a way that it is penetrated by the connection plug of the fuel injection valve, so that a clear installation position is defined for the hold-down. A Verdrehfixierung the blank holder relative to the connection piece is eliminated by the mating pin / recess on the fuel injector / nozzle. The holding-down device is mounted on the fuel injection valve in such a way that a hold-down clip subjected to bending stress is directed away from the connection plug of the fuel injection valve.

drawing

Embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description. Show it FIG. 1 a partially illustrated fuel injection device with a first hold-down in a side view, FIG. 2 the fuel injection device according to FIG. 1 in a perspective view, FIG. 3 A second example of a fuel injection device in a perspective view, FIG. 4 in the fuel injectors of FIGS. 1 to 3 Used hold-down invention as a single component, FIG. 5 a second form of a non-inventive hold-down and FIG. 6 a third form of a non-inventive hold-down.

Description of the embodiments

In the FIG. 1 is an example of a valve in the form of an injection valve 1 for fuel injection systems of mixture-compressing spark-ignition internal combustion engines shown in a side view. The fuel injection valve 1 is part of a fuel injection device. With a downstream end, the fuel injection valve 1, which is designed in the form of a direct-injection injector for injecting fuel directly into a combustion chamber of the internal combustion engine, is installed in a receiving bore of a cylinder head, not shown. A sealing ring 2, in particular of Teflon®, ensures optimum sealing of the fuel injection valve 1 with respect to the wall of the cylinder head. The valve receptacle can also be provided on a receiving socket of a suction pipe, not shown.

The fuel injection valve 1 has at its inlet-side end 3 a plug connection to a fuel distributor line 4, which is sealed by a sealing ring 5 between a connection piece 6 of the fuel distributor line 4, which is shown in section, and an inlet connection 7 of the fuel injection valve 1. The fuel injection valve 1 has an electrical connection plug 8 for the electrical contacting for actuating the fuel injection valve 1.

In order to space the fuel injection valve 1 and the fuel distributor line 4 radially from one another and to hold down the fuel injection valve 1 securely in the receiving bore of the cylinder head or intake pipe, a hold-down device 10 is provided according to the invention between the fuel injection valve 1 and the connecting piece 6. The hold-down 10 is designed as a bow-shaped component, for example as a stamped and bent part. The hold-down 10 has a part-ring-shaped base element 11, wherein this base element 11, which does not rotate through 360 °, but for example has only an extension of about 250 ° to 320 °, is supported on a shoulder 12 of the fuel injection valve 1. With a bent from the flat base member 11, axially resilient hold-down bracket 13 of the hold-down 10 abuts a downstream end surface 14 of the connecting piece 6 to the fuel rail 4 in the installed state. In the area of the electrical connector 8, the hold-down 10 is interrupted, the hold-down 10 forms a closed bracket element, in particular the FIGS. 2 to 4 clarify. In this way, the hold-down 10 can surround the fuel injector 1 and still allows the passage of the electrical connector plug 8. The hold-down bar 13 protrudes with its resilient brackets from the connector 8 away.

In the transition region of the electrical connector 8 to the fuel injection valve 1 at least partially in the region of the inlet nozzle 7 enveloping Kunststoffumspritzung a pin-shaped raised pin 15 is provided on the fuel injector 1, which corresponds to a groove-like depression or recess 16 at the connecting piece 6 of the fuel manifold 4. The projecting into the recess 16 pin 15 of the fuel injector 1 provides a direct and thus very secure rotation of the fuel injector 1 relative to the fuel rail 4 and for a reliable assignment of the rotational position of the blank holder 10 to the fuel injector 1. On the other hand, with the downholder 10 according to the invention a more accurate Alignment of the fuel injection valve 1 with respect to known downholders with integrated Verdrehfixierungen possible, since the component tolerances of the blank holder 10 accounts for the Verdrehfixierung by the embodiment of the invention. The hold-down 10 can also compensate for larger axial tolerances, as is possible with known holders.

The recess 16 on the connecting piece 6 of the fuel distributor line 4 extends from the end face 14 and extends in slot-like or groove-like manner in the axial direction. The recess 16, which is introduced, for example, by machining, has such an axial extent that the pin 15 of the fuel injection valve 1 can be received in full length. In FIG. 2 is the fuel injection device according to FIG. 1 shown in a perspective view. This illustration particularly clarifies the mounting position of the hold-down 10 between the shoulder 12 and the end face 14 and the engagement of the pin 15 in the recess 16.

This in FIG. 3 in a perspective view shown second example of a fuel injection device differs from the in FIG. 2 illustrated example, especially in the execution of the connecting piece 6 and the recess 16. The connecting piece 6 of the fuel distributor line 4 has at its downstream end an annular projecting collar 19 on which the end face 14 is formed to bear the hold 10 with its hold-down bracket 13 and in which the recess 16 is formed. The groove-like recess 16 is completely penetrated by the pin 15 in the installed state of the fuel injection valve 1. In the example deep-drawn connection piece 6, the recess 16 is introduced by means of punching or by machining.

In the FIGS. 4 to 6 For example, three forms of hold-downs 10 are shown, with the in FIG. 4 as a single component shown holding-down device 10 in the fuel injectors of FIGS. 1 to 3 used holdings corresponds to 10. All forms are characterized by the fact that, starting from a planar part-ring-shaped base element 11, at least one bent, axially resilient hold-down bracket 13 extends out of the plane of the base element 11.

As already described, the connector 8 of the fuel injection valve 1 extends through the open area 20 of the base element 11 of the hold-down 10. The base element 11 can be substantially circular (FIG. FIGS. 4 and 5 ) or depending on the shape of the fuel injection valve 1, for example pear-shaped ( FIG. 6 ) or similar in cross section. At the in FIG. 4 illustrated example, the base member 11 is made flat, for example, with a thickness of about 1.5 mm, so that a large bearing surface on the shoulder 12 is present. In contrast, the basic elements 11 of the hold-down 10 of the FIGS. 5 and 6 upright, for example, in turn, with a wall thickness of about 1.5 mm, but thus also dictates the small width of the support surface of the respective base member 11 on the shoulder 12.

The hold-down 10 according to FIG. 4 represents a closed bracket member, since the hold-down bar 13 is connected endlessly to the base member 11. From the base member 11, two webs 21 extend with increased width largely in the axial direction and thus substantially perpendicular to the extension plane of the base member 11. These webs 21 go kinked into the actual axially resilient holddown 13, wherein the hold-down bracket 13 composed of three essential sections. The hold-down bar 13 has, starting from the webs 21, only a small axial extent, which results from two uniform oblique sections 22. The oblique sections 22 merge into slightly curved contact sections 23 which, in the installed state, ultimately have touching contact with the end face 14 of the connecting piece 6. Between the abutment portions 23, a connecting portion 24 is provided, which is carried out slightly lowered relative to the abutment portions 23 and ensures that the entire hold-down device 10 is closed. The circumferential extent of the hold-down strap 13 with its sections 22, 23 and 24 largely corresponds to that of the base element 11, but in a different axial plane, caused by the height of the webs 21st

In contrast to the hold-down device 10 described above, the hold-down device 10 according to FIGS. 5 and 6 no connection portion 24, so that an overall open holddown 10 is present. From the base element 11 in turn two webs 21 extend substantially in the axial direction and thus substantially perpendicular to the plane of extension of the base member 11. The webs 21 extend with respect to their wall thickness twisted relative to the base member 11, wherein the transition region 25 inward ( FIG. 6 ) or outside ( FIG. 5 ) can be turned. As FIG. 6 shows, the webs 21 may have a curved, for example S-shaped configuration. The webs 21 go over bent into the actual axially resilient hold-down bar 13, wherein the hold-down bar 13 composed of two sections. The hold-down bar 13, starting from the webs 21 only a small axial extent, resulting in two uniform oblique sections 22. The oblique sections 22 merge into slightly curved contact sections 23, which ultimately come into contact with the end face 14 of the contact-making contact in the installed state Have connecting piece 6. The two abutment sections 23 of each hold-down 10 terminate the two-part hold-down bar 13 in this way.

The entire hold-down bar 13 with its inclined sections 22 and abutment sections 23 and the connecting section 24 in turn has a wall thickness of about 1.5 mm, while the width of the hold-down bar 13, in particular of the abutment sections 23 is greater.

All described downholders 10 are used e.g. separated by punching, eroding or laser cutting from sheets of spring steel or stainless steel (with a thickness of about 1.5 mm) and then brought by bending in the desired shape. All forms of the blank holder 10 have in common that the bending stress stressed surfaces of the blank holder 10, in particular the inclined portions 22 and the abutment portions 23 perpendicular to the cutting edges 27, which are defined in the extraction of the blank for the blank holder 10 from the corresponding sheet.

Claims (8)

1. Hold-down for a fuel injection apparatus which comprises at least one fuel injection valve (1), one receiving hole for the fuel injection valve (1) and one connection piece (6) of a fuel distributor line (4), it being possible for the hold-down (10) to be clamped in between a shoulder (12) of the fuel injection valve (1) and an end face (14) of the connection piece (6), the hold-down (10) having a part-annular basic element (11), from which an axially resilient hold-down shackle (13) extends in a bent-away manner, which hold-down shackle (13) has at least two webs (21), two oblique sections (22) and two contact sections (23), and the basic element (11) being configured as a flat part ring in accordance with the sheet-metal thickness which is used, and the two contact sections (23) of the hold-down shackle (13) being connected directly to one another via a connecting section (24), with the result that the entire hold-down (10) forms a closed shackle element.
2. Hold-down according to Claim 1, characterized in that the basic element (11) of the hold-down (10) can be placed onto the shoulder (12) of the fuel injection valve (1).
3. Hold-down according to Claim 1 or 2, characterized in that the contact sections (23) of the hold-down shackle (13) can be placed onto the end surface (14) of the connection piece (6).
4. Hold-down according to one of the preceding claims, characterized in that those surfaces of the oblique sections (22) and contact sections (23) which are loaded by flexural stress extend perpendicularly with respect to the cut edges (27) which are produced when the blank for the hold-down (10) is released from the corresponding metal sheet.
5. Hold-down according to one of the preceding claims, characterized in that it is configured as a stamped bent part.
6. Hold-down according to one of the preceding claims, characterized in that the metal sheet which is used for the hold-down (10) is composed of spring steel or stainless steel.
7. Hold-down according to Claim 4 or 6, characterized in that the hold-down (10) has a wall thickness of approximately 1.5 mm in accordance with the sheet-metal thickness which is used.
8. Hold-down according to Claim 1, characterized in that the circumferential extent of the hold-down shackle (13) corresponds largely to that of the basic element (11).

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