DE102008057517A1 - Distributor pipe of fuel injection system of internal combustion engine for motor vehicle, comprises a tube-like main metal body having a hollow dome-like distributing metal sockets, which are connected with the interior of the main body - Google Patents

Abstract

The distributor pipe (1) of a fuel injection system of an internal combustion engine comprises a tube-like main metal body (2) having a hollow dome-like distributing metal sockets (3), which are connected with the interior of the main body in a fluid-guiding manner and have a plastic connection piece (4) molded onto the distributing socket and surrounding its end side. The distributing sockets arranged at the circumference of the main body are encapsulated together with the plastic, so that the distributing sockets are arranged and lockingly connected with one another by the connection piece. The distributor pipe (1) of a fuel injection system of an internal combustion engine comprises a tube-like main metal body (2) having a hollow dome-like distributing metal sockets (3), which are connected with the interior of the main body in a fluid-guiding manner and have a plastic connection piece (4) molded onto the distributing socket and surrounding its end side. The distributing sockets arranged at the circumference of the main body are encapsulated together with the plastic, so that the distributing sockets are arranged and lockingly connected with one another by the connection piece forming the plastic. Positive fit elements are formed on the outer side of the main body and are surrounded by plastic. An injection nozzle is kept at the connection piece using a clip. A reinforcing rib and/or a screw-on point are molded onto the main body. The screw-on point forms a mounting flange, by which the distributor pipe is fixable at the motor. The plastic is permanently heat-resistant up to a temperature of 150[deg] C, where the metal is iron-containing material or light-metal material. The main body of the distributor pipe has a closure at one end. The closure is formed by a threaded plug or a welded plate. An end of the main body is curved and forms the distributor pipe. An independent claim is included for a method for manufacturing a distributor pipe of a fuel injection system of an internal combustion engine.

Description

The The invention relates to a manifold of a fuel injection system an internal combustion engine according to the preamble of claim 1 and a method for its production according to the Preamble of claim 12.

From the DE 10 2006 010 244 B3 Fuel rail is known with a manifold for supplying fuel to injection valves of an internal combustion engine, are arranged on the branch piece for connection of injection valves and mounting elements for fastening the fuel rail to the internal combustion engine. The manifold, the branch pipe and the mounting elements are made of metal. The mounting element is defined by a plastic injection molding on the manifold and the branch pipe. The plastic injection molded part forms a junction piece between manifold and branch pipe. For each branch piece a plastic injection molded part is provided. This creates a permanently strong connection between the components. However, the knot piece made of plastic merely serves for attaching the distributor tube to another component, so that the distributor tube is position-determined relative to this second component. There is only a local definition.

The formation of manifolds by hydroforming is in the EP 1318292 B1 disclosed. In this case, hollow-drilled blocks are threaded onto a carrier tube, which each have a radial channel with an outlet which forms an injection opening. Between each block and the support tube, a seal is placed beforehand. Thereafter, the support tube is inserted in the sliding assembly with the blocks in the mold space of a hydroforming and set under internal high pressure. In this case, the tube is widened between the blocks, so that they are enclosed axially form-fitting manner. At the same time creates a very high frictional engagement within the block between tube and block, so that the blocks are immovably fixed to the support tube. Finally, pin holes are inserted, which are passed through the respective radial channel and perforate the support tube, so that a passage from the interior of the support tube is provided on the radial channel to the outside.

From the US 7,263,975 B2 a fuel rail for an internal combustion engine can be removed, which consists of reducing the weight and the manufacturing cost of a metallic tube with a circumferentially formed fuel inlet and fuel outlet, which is closed at both ends with plastic caps. The fuel inlet is formed on the circumference of the tube in the immediate vicinity of one end, wherein at this inlet a supply line is attached, which is held by the local plastic cap with a passage. The tube consists of an inner metallic layer and an outer layer of plastic. This is intended to achieve the weight advantages. Furthermore, at least one holder is attached to the tube by means of a substantially C-shaped base portion integrally connected thereto, either by a snap connection or by other attachment means. The holder serves to receive an injection nozzle.

The known from the prior art distribution pipes have the disadvantage on that they are either very heavy and thus to a high weight lead the entire engine, which ultimately increased Consumption of such a manifold having internal combustion engine pulls. Or / and they are very expensive to manufacture.

It Therefore, the object of the present invention is simpler here Production possibility a weight-reduced design allow a distributor pipe. This should become one Weight reduction and a cost reduction lead. For this should also be given a procedure.

The The object is achieved by the features of claim 1 with respect to the manifold and through the features of claim 12 with respect to the manufacturing process solved.

Characterized in that in a generic manifold according to the invention, the manifold has a molded-on this and at least end surrounding him connector made of plastic, the manifold is lighter, thereby reducing the consumption of a motor vehicle, in which an internal combustion engine is used with such a manifold reduced become. The encapsulation represents a with little effort to be operated production technology, the con nection piece can be formed very accurately. This represents an alignment with the manufacturing technology of the main body by means of hydroforming, since this can hereby be formed with high-precision and very high-quality surfaces. In this way, the production costs are reduced for the production of a precisely reproducible highly accurately formed manifold, which offers a special competitive advantage. Since the spray material contracts on cooling, it shrinks towards the manifold neck on this, so that the formed connector has a very good grip on the neck. For this purpose, no additional connection techniques or separate connection components are required which saves weight and further reduces production costs. An even better grip can be achieved by the connecting piece when the spray material in the area of the distributor socket is also sprayed around the main body, thereby giving an intimate, immovable positive fit in all spatial directions. The latter method step can be found in the particularly preferred embodiment of the method according to claim 14, in which the main body is formed in a tool in the hydroforming and molded in sections in the same tool with plastic. Due to the sequence of two completely different manufacturing processes in a single tool, the production cost is significantly reduced and a particularly high reproducible precision in the formation of the manifold achieved because the component to be manufactured does not have to be converted from one tool to another. Furthermore, the production time is shortened.

In a particularly preferred embodiment of the invention Distributor tube according to claim 2 or of the method according to claim 22 are several arranged on the circumference of the main body Manifolds molded together with plastic, so that the assigned to each manifold and formed by the plastic Connecting pieces are connected to each other cohesively. This will stop the fittings on the main body or even further improved on the dome-shaped manifold, because they hold each other by the material consistency. It is also advantageous that, although several cavities with multiple injection channels can be used, the Providing only a single cavity, consisting of several interconnected Teilkavitäten consists, with a single injection channel is conceivable. This leaves a strong one apparatus simplification too.

The dome-shaped manifold can, moreover in a preferred embodiment of the invention Method according to claim 20 by means of fluidic internal high pressure be shaped out of the main body at the same time can be done with the formation of the entire main body and therefore very process-economical. With the shape The manifolds are also like the rest of the main body formed with high precision. If necessary, in particular for a process-reliable training larger Forming lengths of the manifold during the Hydroforming from the ends of the main body to the or the Ausformbereichen body material, for example be nachschoben by stamping.

Around a further improvement of a hold of the plastic material to reach the main body or on the manifold, is in a preferred embodiment of the invention according to claim 3 provided that on the outside, in particular on Scope of the main body form-fitting elements formed are embraced by the plastic. Here, the slip resistance of Plastic supports. The form-locking elements can otherwise alternatively or additionally be formed the manifold neck.

It is also advantageous if, according to a preferred Development of the invention according to claim 4 on the connection piece an injection nozzle is held by means of a clip. On This way is a simple assembly and disassembly of the injector possible. Also, the clip can be made of plastic and be sprayed on the manifold.

According to one particularly preferred embodiment of the invention according to claim 5 is at the main body at least one reinforcing rib and / or sprayed on a screw-on. This makes it possible over the attachment point the main body and thus the manifold on a component of the internal combustion engine particularly fast and easy to set. The reinforcing rib is used for Stiffening of the main body, making this even lower Wall thicknesses can be formed without special losses to accept in the strength, what the lightweight construction the distributor pipe favors. Furthermore, a reinforcing rib be formed in the area of screw-on, so there even large tightening torques can be used without that the manifold is damaged.

According to one preferred embodiment of the invention according to claim 6 forms the Anschraubstelle an attachment flange, by means of which the manifold attachable to the engine. As a result, the Anschraubstelle the Contour of the motor can be adjusted accordingly, so that for attachment to an improved force application for screwing is given and on the other hand, the manifold stably rests on the engine.

Around to ensure a durable use of the manifold, is in accordance with a preferred embodiment of The invention according to claim 7, the plastic at least up to one Temperature of 150 ° C permanently heat resistant.

In terms of longevity it is beneficial if, according to a Preferred embodiment of the invention according to claim 8, the metal is an iron-containing material. The fatigue strength relative to The specific gravity can be optimized when the metal a light metallic material.

In a particularly preferred embodiment of the invention according to the Claim 11 with respect to the subject of the manifold and claim 19 regarding the associated manufacturing method one end of the main body is bent, which then one the manifold forms. The bending process can take place in such a way that first in a separate bending tool a pre-bent state of the main body is reached, after which by closing the combination tool from hydroforming and Injection molding the final bending shape is achieved. Of course, also the final bending shape already by a bending process before introduction into the Combination tool can be achieved. By passing the can Distribution pipe can be better adapted to the space requirements, whereby a compaction of the engine compartment is favored.

by virtue of the special training of the end is on the one hand at this point forming a manifold from the main body no longer necessary, which is also relatively difficult, if not would be impossible, since the tubular Main body at least during hydroforming both ends must be sealed and thus the end for a local Forming is really out of the question. The other is now the otherwise unusable end functionally applicable and the length of the main body can be better use for the formation of manifolds. Furthermore accounts for additional closure means and the associated joining or assembly process for this End, which simplifies the manufacturing process of the manifold and accelerates.

Especially, if such a bending operation is not taken into account It is necessary to have the ends of the main body during the entire manufacturing process ses seal, so no plastic can flow into the interior of the main body, what that for the training of the fittings Reduce the amount of plastic material available and would make the manifold unnecessarily heavier. In addition, care must be taken to ensure that no pressure fluid penetrates outward from inside the main body, because this is the application of plastic by injection molding hinder or prevent. An appropriate seal can be achieved by axial punches in the main body immerse end.

Around to improve the tightness even further, receives according to a preferred embodiment of the invention according to claim 9 of the main body a closure at one end. Of course, the shutter also due to the function of the distribution pipe necessary, since the introduced into the manifold fuel exclusively via supplied to the manifold of the internal combustion engine and maintain the pressure level of the pressurized fuel shall be. The application of the closure can already before the hydroforming done, thereby simplifying the apparatus an axial stamp is saved. However, it is also possible the closure after hydroforming, but in any case before injection molding on the main body of the To install distribution pipe. The closure can be unsolvable or detachably connected to the main body.

In one due to its simple design and construction preferred development of the invention according to claim 10 and 21 the closure is represented by a threaded plug or to the main body of the manifold at the end a plate pressure and fluid tight welded.

To the molding or encapsulation of the manifold with the connector this is usually closed. To guarantee the function of the manifold during operation is the respective connector to open, thus fuel over the main body and the manifold to the associated injector can get. A variant to achieve the opening according to a preferred embodiment of the invention according to claim 13, in the pressure and fluid-tight connected to the manifold neck Connecting piece to drain channels into the Lead inside of the main body. As it is here to a connection action to the combined method hydroforming and injection molding turns and outside the combination tool is done, there is no way to make these processes undesirable to influence.

A Variant for this according to a preferred embodiment The invention according to claim 15 is that a pin in an existing prior to the injection molding opening the respective manifold is used, the opening for the time being, d. H. during injection molding closes and then removed again. The pin protrudes from the manifold out and is infused with. He forms the channel cross-section in the fitting and holds the channel opposite the increasing fluid injection molding free. The elaborate subsequent generation and / or reworking of the channels is avoided. Furthermore, the production time is barely extended as the channels are virtually simultaneous be formed with the generation of the connecting piece and only the pins have to be moved back. The pins can be integral with the forming tool be connected or movable in this led.

The mentioned opening at the manifold, which is the inside of the main body of Ver Divider tube connects to the environment, can be punched in a simple manner according to a preferred embodiment of the invention according to claim 16 by means of a punch. The punch may preferably be part of the forming tool.

In a particularly preferred embodiment of the invention according to the Claim 17, the punch in the opening to the Completion of the plastic injection process remain in this sealing. This represents another variant for the formation of the channels which further simplifies the manufacturing apparatus, since the Punch is used multifunctional. Here he serves both for opening the distributor socket as well as for closing the opening and to the formation of the channel and replaced with the latter function the above pin. Again, it will be the plastic impossible, inside the main body penetrate. In addition, a seal of the main body against realized a pressure drop within the main body.

In a particularly preferred embodiment of the invention according to the Claim 18 is during the plastic injection process inside the main body a fluidic support pressure on, which corresponds at least approximately to the injection pressure. This prevents the main body from passing through the Injection pressure is incident, whereby otherwise a bad part produced and would give a production failure.

The Invention will become more apparent hereinafter with the aid of drawings explained.

It demonstrate:

1 an inventive distributor tube in a plan view,

2 an inventive manifold, as in 1 shown in a side view,

3 a detail of a on a main body of the in 1 and 2 illustrated manifold according to the invention formed manifold manifold with attached connector,

4 a further inventive distributor tube of a further embodiment in a plan view,

5 an inventive manifold, as in 4 shown in a side view,

6 a detail of a on a main body of the in 4 and 5 illustrated manifold according to the invention formed manifold manifold with attached connector,

7 an enlarged section in area VII of 6 .

8th a further embodiment of the attachment of the connection body on the main body and

9 the embodiment of 8th with enlarged representation of positive locking elements to improve the adhesion of the plastic to the outside of the manifold.

The Figures are merely schematic in nature and are for understanding only the invention. The same elements are given the same reference numerals Mistake.

In 1 is a distributor tube according to the invention 1 shown. This distribution pipe 1 is used in a fuel injection system of an internal combustion engine. The internal combustion engine is in turn used in cars or trucks.

The Fuel Injection System is a high pressure device, such as a common-rail injection system for diesel fuel. Indeed are also gasoline direct injection systems here to be considered.

The manifold 1 has a main body 2 on. The main body 2 is a hollow cylinder or a pipe. From the main body 2 outgoing are hollow dome manifolds 3 formed with the interior of the main body 2 be in fluid communication. As in the in the 1 and 2 illustrated embodiment, the manifolds are 3 of the main body 2 as dome-shaped expansions of the main body 2 educated.

The manifolds 3 are formed in a hydroforming process. The main body 2 with its manifolds 3 is made of metallic material, in particular steel or light metal. At the manifold 3 are made of plastic fittings 4 appropriate. The fittings 4 are doing during a manifold 3 overmoulding process formed and stand with the interior of the main body 2 in connection.

About a clip solution injectors are at the Anschlusstücken 4 attached.

For the production of the manifold 1 this is made of steel or light metal by means of hydroforming formed as needed. For this purpose who the high pressure-tight seal two Axialstempel in the two open ends of the main body 2 , which was previously placed in a split hydroforming, pushed. After closing the tool, a pressure fluid is introduced into the interior via corresponding channels in the axial dies and the pressurized fluid is pressurized. In the resulting expansion, the dome-like spigot 3 educated.

The detailed presentation 3 facilitates understanding of the structure of the manifold 1 ,

In a first embodiment of the method, the deformed distributor tube is removed from the hydroforming tool and provided with threads at one end in separate working steps. At the other end it is closed. The closure can be realized by a threaded plug or by a welded plate. Furthermore, the machined manifold 1 are subsequently inserted in an injection mold and at the points of the manifold 3 be overmoulded with plastic. During encapsulation, the fittings become 4 formed for the injectors, which are held at this later about by means of clips.

It will also be on the outside of the manifold 1 , in particular on the main body 2 , Reinforced ribs and screwed points, which are designed as flanges for attachment to the internal combustion engine. For a better grip on the manifold 1 are all encapsulations by the plastic together, and thus cohesively, connected.

In another embodiment, the main body comprises 2 Furthermore positive locking elements, where the plastic finds a non-slip grip. After encapsulation, the finished component is removed from the injection mold and in the fittings 4 For example, the necessary channels are introduced by drilling. In the process, the manifolds will also be used 3 open. The fittings 4 However, surrounded pressure and fluid-tight, the manifold 3 ,

The closure of one end and the thread of the other end of the main body 2 forming tube is formed after the encapsulation. It is important to ensure that no plastic in the distribution pipe during the overmolding 1 So the main body 2 penetrates. In this framework, it is possible to open the manifold 3 already in hydroforming process to create, for example by means of stamping. The openings reached are, as already explained, closed again before Umspritzungsvorgang. It is advantageous if in the openings preferably a pin is inserted, the thickness of the clear width of the later channel in the connection piece 4 has. When encapsulating then the channel to be reached is recessed, so that a costly reworking of the channel after the encapsulation is omitted. The openings go over into the channels.

In one in the 1 to 3 not shown embodiment, an apparatus simplification is performed such that the manifold 1 so it is prebent that one end of the main body 2 already a manifold 3 forms. A later processing to create the opening in the manifold 3 is therefore unnecessary and a closure of one end of the main body 2 can also be omitted.

The process can be carried out in a particularly cost-effective manner if the entire process takes place with a single tool which is capable of being subjected to high pressure forming and injection molding and which is formed, for example, by a hydroforming die modified for the application of the injection molding method. For example, the punches that are the openings in the manifold 3 create, leave in the openings until the completion of the plastic extrusion. The punches then form on the one hand a seal of the main body 2 against a pressure drop and on the other hand a seal against the inflow of plastic into the interior of the main body 2 , A certain support pressure within the main body 2 is advantageous because it ensures that the injection pressure does not cause the main body to collapse 2 leads.

If but cavities for the formation of the encapsulation are relatively large, such that due to the expansion Pressed by means of hydroforming tube material could be, so are slides or similar Devices, the cavities during the forming process shut up, hold up. The thread for the one end and the closure for the other end are then in a subsequent operation outside this to make a single tool.

The inventively produced metal hybrid manifold 1 impresses with its unrivaled low weight, because the metal tube ensures the required pressure resistance even with small wall thicknesses operationally and all fittings 4 and flanges are formed by lightweight plastic. Furthermore, the method is relatively simple and fast.

As a variant of the embodiments, as in the 1 to 3 are shown in 6 in the area of an opening 5 , a capping zone 6 indicated. In the capping zone 6 becomes part of the dome-shaped bulge, namely a dome 3a that the manifold 3 trains, separated. This is done by drilling or punching.

That following the severing a stamp-like mold core 7 with a cone tip adjacent to the opening 5 can be used to act as already explained sealing, is also indicated.

While in 6 the main body 2 with a full encapsulation 9 is completely encapsulated, is in 8th a partial encapsulation 10 shown.

The detailed representation in 7 shows how the dome 3a at the by the capping zone 6 trained beveled cut off.

That the ends of the opening 5 a beaded overhang 13 form, that is 9 refer to. Adjacent to this area are ruffles 14 , Grooves or furrows on the outer surface of the main body 2 educated. The cantilever 13 and the ruffles 14 form an example of the positive locking elements that can be embraced by the molded plastic to improve the grip.

In the 4 a dashed groove is shown as a rear handle option for a clip in the attachment of an injector, not shown.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102006010244 B3 [0002]
• - EP 1318292 B1 [0003]
• - US 7263975 B2 [0004]

Claims (22)

Distributor tube ( 1 ) of a fuel injection system of an internal combustion engine, with a tube-shaped main body made of metal ( 2 ), the at least one hollow dome-like manifold ( 3 ) of the same material, which carries fluid with the interior of the main body ( 2 ), characterized in that the manifold ( 3 ) on this molded and at least end surrounding him connector ( 4 ) Made of plastic. Distributor tube ( 1 ) according to claim 1, characterized in that several at the periphery of the main body ( 2 ) arranged distributor neck ( 3 ) are molded together with plastic, so that the each manifold ( 3 ) and formed by the plastic fittings ( 4 ) are materially connected to each other. Distributor tube ( 1 ) according to claim 1 or 2, characterized in that on the outside of the main body ( 2 ) Forming elements are formed, which are encompassed by the plastic. Distributor tube ( 1 ) according to one of claims 1 to 3, characterized in that on the connecting piece ( 4 ) An injection nozzle is held by a clip. Distributor tube ( 1 ) according to one of claims 1 to 4, characterized in that on the main body ( 2 ) At least one reinforcing rib and / or Anschraubstelle is molded. Distributor tube ( 1 ) according to claim 5, characterized in that the bolting point forms a mounting flange, by means of which the distributor pipe ( 1 ) is attachable to the engine. Distributor tube ( 1 ) according to one of claims 1 to 6, characterized in that the plastic is durable heat resistant at least up to a temperature of 150 ° C. Distributor tube ( 1 ) according to one of claims 1 to 7, characterized in that the metal is an iron-containing material or a light metal material. Distributor tube ( 1 ) according to one of claims 1 to 8, characterized in that the main body ( 2 ) of the manifold ( 1 ) has a closure at one end. Distributor tube ( 1 ) according to claim 9, characterized in that the closure ( 12 ) is formed by a threaded plug or a welded plate. Distributor tube ( 1 ) according to one of claims 1 to 8, characterized in that one end of the main body ( 2 ) is bent and a manifold ( 3 ). Method for manufacturing a distributor tube ( 1 ) of a fuel injection system of an internal combustion engine, wherein a tubular main body ( 2 ) of metal a hollow, dome-like manifold ( 3 ) fluidly communicating with the interior of the main body ( 2 ), which is formed in an internal high-pressure forming step, characterized in that the manifold ( 3 ) at least end to form a connection piece ( 4 ) is injection molded with plastic for an injection nozzle forming plastic component. A method according to claim 12, characterized in that in the pressure and fluid-tight with the manifold neck ( 3 ) connected connector ( 4 ) into the interior of the main body ( 2 ) leading channels are drilled. Method according to one of claims 12 or 13, characterized in that the main body ( 2 ) is formed in a tool with internal high pressure and molded in sections in the same tool with plastic. A method according to claim 12, characterized in that prior to the plastic injection process, a pin in an opening of the respective manifold ( 3 ) is used, which closes the opening and is removed after the injection process again from the opening. A method according to claim 12, characterized in that at the manifold ( 3 ) is punched out by means of a punch an opening that the interior of the main body ( 2 ) of the manifold ( 1 ) connects to the environment. Method according to claim 16, characterized in that that the punch in the opening until the completion the plastic injection process this remains sealing. Method according to one of claims 12 to 17, characterized in that during the plastic injection process inside the main body ( 2 ) A support pressure is applied, which corresponds at least approximately to the injection pressure. Method according to one of claims 12 to 18, characterized in that one end of the main body ( 2 ) to a manifold ( 3 ) is pre-bent. Method according to one of claims 12 to 19, characterized in that from the main body ( 2 ) are formed by means of fluidic internal high-pressure dome, the manifolds ( 3 ) of the distributor tube ( 1 ) form. Method according to one of claims 12 to 20, characterized in that the main body ( 2 ) is sealed before the injection process at one end by means of a threaded plug or by welding a plate. Method according to one of claims 12 to 21, characterized in that a plurality of manifolds ( 3 ) are encapsulated with plastic, wherein the thereby formed connecting pieces ( 4 ) are joined together materially.