KR102447585B1 - Device of a fuel injection system and metal-to-metal sealing connection arrangement - Google Patents

Abstract

The device 1 of the fuel injection system comprises a fuel guiding component 2 and a connection 3 . In this case, a metallic sealing connection unit 4 comprising a first metallic connecting partner 6 and a second metallic connecting partner 5 is provided. The metal connection partners 5 , 6 can be connected to each other with respect to the axis 12 , in which case the first connection partner 6 is provided with a conical sealing surface 15 , said second connection partner 5 . A sealing profile 19 is formed which is assigned to the conical sealing surface 15 of the first connecting partner 6 . The sealing contour 19 of the second connection partner 5 has in its initial state a peripheral elevation 18 extending around the axis 14 , said elevation having a conical sealing face 15 of the first connection partner 6 . ), the sealing contour 19 of the second connection partner 5 forms a conical sealing of the first connection partner 6 with the raised portion 18 of the second connection partner 5 deformed in the screwed state. In order to form a metal seal between the faces 15 , the peripheral elevation 18 of the second connection partner 5 is at least partially formed during screwing of the second connection partner 5 and the first connection partner 6 . It is formed to be plastically deformed.

Description

DEVICE OF A FUEL INJECTION SYSTEM AND METAL-TO-METAL SEALING CONNECTION ARRANGEMENT

The present invention relates to a metal-sealed connection unit and a device for a fuel injection system comprising the metal-sealed connection unit. In particular, the present invention relates to the field of fuel injection systems for internal combustion engines.

DE 10 2008 035 492 A1 discloses a rail assembly for a fuel injection system. The rail assembly is used in particular for internal combustion engines of automobiles. In this case, a supply pipe for supplying and providing fuel in a low pressure state and a plurality of branches fixed to the supply pipe for fluidly connecting the supply pipe to each fuel injector are provided. The supply tube also has an inner contour at the axial end into which the pressure sensor connection is inserted, said inner contour being conical in shape complementary to the outer contour of the insertion section. Said conical inner contour with an outwardly extending inner cross-section in this case can only be formed by axial press-fitting of the insertion section. This makes it possible to ensure that the inner contour of the feed tube is formed exactly complementary to the outer contour of the insertion section.

The rail assembly disclosed in DE 10 2008 035 492 A1 and the connection provided in this case and formed by axial press-fitting has the disadvantage that the pre-stresses appearing in the connection are not generally determined. Very large forces can be generated in this case, especially by means of axial press-in, which necessitate a suitable design of the connection partner. Since the cone angle of the conical inner contour is very small, the resulting tensile forces can become quite large very quickly, and therefore an adequate possibility of deformation of the supply pipe must be ensured.

In an embodiment of the connection of the fuel reservoir with the pressure sensor, it is conceivable that a screw connection is used. In this case sphere/cone or cone/cone connection pairs with displaced contact surfaces can be considered. In this case, screwing by a predetermined rotational moment is possible, and the interface is sealed by surface contact. Due to material pairs and geometrical tolerances, plastic deformation of only one connecting part or of the two connecting partners takes place in this case. However, in this case, there is a problem that the shape of the sealing position can be significantly changed due to various influences by the rotational moment controlled assembly. The main influence in this case is the fluctuation of the friction value. This is particularly undesirable, since very large safety factors have to be set in the design of the connection partner to ensure minimal strain or pre-stress.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a device for a fuel injection system and a metal sealing connection unit in which the above disadvantages are eliminated.

The above object is solved according to the invention by a metal sealing connection unit comprising the features of claim 1 and a device for a fuel injection system comprising the features of claim 10 .

The device according to the invention of a metal sealing connection unit according to the invention comprising the features of claim 1 and of a fuel injection system comprising the features of claim 10 offers the advantage that an improved shape and operation are possible. An improved sealing action can be achieved, especially with regard to the use of the provided material. Especially in this case, the power density can be increased in the same assembly space, so that it can be sealed against higher pressures. Thus, material usage can be reduced to achieve a given demand. This also allows for an inexpensive implementation of a sealing function capable of sealing against the internal pressure of the fuel guiding component, in particular the fuel distributor.

By means of the measures presented in the dependent claims, advantageous improvements of the metallic sealing connection unit presented in claim 1 and the arrangement of the fuel injection system presented in claim 10 are possible.

In particular, use can take place in fuel injection systems for gasoline direct injection, in which case an air-fuel mixture is formed inside the cylinder combustion chambers of an internal combustion engine designed as a gasoline engine. For this purpose, fuel is injected into the combustion chamber at high pressure. The fuel distributor can in this case be used as an accumulator and for distributing fuel to a number of fuel injection valves. For controlling, in particular regulating, the pressure in the injection system, a sensor can be used, which enables at least one pressure measurement and is preferably designed as a high-pressure sensor.

Special requirements are given if a screw connection has to be implemented, in particular for connecting such a pressure sensor with a fuel distributor block for gasoline direct injection. One connection partner may be a screw socket which guides the internal pressure and has a sealing function. For other connection partners, the pre-stress can be maintained not by the screw head, but by the sealing cone. During possible screw tightening with a predetermined rotational moment, significant fluctuations in the shape of the sealing position appear, which in particular are caused by fluctuations in the friction values. Alternatively, it is advantageous if, in addition to the sealing position, the screwing depth or spacing of the connection partners is adjusted.

In this case, preferably, a sealing is possible at the metal interface between one connection partner, eg the base body of the fuel reservoir, and another connection partner, eg an installation part. The metal interface comprises a rotatable bolt having a thread and a conical sealing surface, a fixed nut having a thread and a spherical or toric sealing seat, the relative movement of two mating partners (sealing partners) by rotational motion during screwing of the bolt and It is characterized in that a plastic deformation of one connecting partner is provided due to a pre-stress for sealing against the fuel.

In this case, in a possible variant, spherical or toric bolts and conical nuts may also be used. Also, the mounting part in the sealed position may be a sensor. Furthermore, plastic deformation can only be effected at the pressure sensor connection by means of a suitable material pair. The target setting of the sealing sheet width at the time of initial assembly of the interface can be achieved by the assembly method of the rotation angle control method. A provided bolt may be configured to guide the internal pressure. The cone angle at the bolt may be approximately 60° to 120°. In addition, the radius of the nut side may be formed so that the pressure sensor connection part is not completely plastically deformed even when the maximum pressure is applied.

In an embodiment of the metal sealing connection unit, it is preferred that the peripheral riser is formed as a spherical and/or toric body. Formation into a torus is in this case a shape corresponding to the partial shape of the torus, in particular the convex shape is predetermined. The spherical shape is usually a partial form of a torus. Due to this, a shape in which the plastic deformation of the second connecting partner is limited to the peripheral riser is possible. Furthermore, a desired peripheral seal can be achieved by means of plastic deformation, whereby a sealing profile having at least approximately a predetermined size of the resulting sealing surface is set as intended. It is therefore also advantageous for the plastic deformation between the first and second connection partners to appear only in the sealing contour of the second connection partner.

In particular, in this case, it is preferable that the peripheral riser of the second connection partner is formed such that only partial plastic deformation of the riser occurs during the maximum settable plastic deformation of the peripheral riser. The threaded engagement between the first and second connection partners is in this case advantageously such that the sealing seat width at the deformed rise between the first and second connection partners is between the first and second connection partners. It may be formed to be settable by a rotation angle. The magnitude of the plastic deformation of the sealing contour of the second connecting partner in this case is also predetermined by the predetermined angle of rotation.

It is also preferred that a conical sealing area is formed by plastic deformation of the sealing contour of the second connecting partner, in which case a conical sealing area having a predetermined conical angle is formed by the conical sealing surface of the first connecting partner. Due to this, an effective predetermined sealing surface, in particular the size of the sealing surface, can be reliably established. In this case, there is also a clear independence from possible manufacturing tolerances and friction value fluctuations.

In a possible embodiment, it is preferred that the first connection partner is formed as a bolt with an axial bore and the second connection partner is formed as a socket with an axial through bore. In this case, the axial bore or the axial through-bore may be formed "axially" only with respect to the sealing area, but not necessarily "axially" with respect to the entire part. In another possible embodiment, it is preferred that the first connection partner is formed as a socket with an axial bore and the second connection partner is formed as a bolt with an axial bore. Due to this, plastic deformation can only take place on one of the connection partners, as intended, depending on the application, specifically for the connection of sensors, in particular pressure sensors.

This also provides the advantage of being given a defined contact point or a defined contact line around the perimeter at the start of the screwing. Experiments have shown that in the case of material pairs of mainly similar steels, for example corrosion-resistant steels, sometimes a cold shut appears in the sealing cone. This can be explained in particular by the local high stress at the edge of the provided chamfer. This is countered in particular by the spherical or toric sealing contours in the seat, since this results in a uniform rise in stress.

By means of an optimized assembly process, the plastic deformation can be established precisely within a given size and preferably without dependence on friction. Another advantage is that the thread strength can be better exploited by the optimized assembly process, since the fluctuation of the pre-stress is smaller and thus a smaller difference from the maximum thread stress is possible.

A deformed metal sealing ball/coone-connection, which preferably rotates in the contact area, can be realized after assembly, in which case the sealing contour in the contact area is formed in the form of a spherical or toric shape, so that the "ball" has a spherical or toric shape. transformed as part of the body. The material pair results in a plastic deformation of the sealing contour upon screwing, while the first connecting partner is not plastically deformed, in particular in the contact area to the sealing contour. By plastic deformation of the sealing contour of the second connection partner, a conical sealing area with a predetermined cone angle is formed by the first connection partner. By means of the shape of the cone area, the necessary sealing length and pre-stress can be set very precisely. This is achieved in particular by means of a geometrical relationship between the thread pitch and the angle of rotation using an assembly method with a controlled rotation angle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention are described in the following description with reference to the accompanying drawings, in which corresponding elements have the same reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an excerpt schematic cross-sectional view according to a first embodiment of the invention of a device of a fuel injection system comprising a connecting unit before assembly;
FIG. 2 shows a part of the connecting unit indicated by II in FIG. 1 according to a first embodiment of the present invention; FIG.
Fig. 3 shows a part of the connecting unit indicated by II in Fig. 1 according to a second embodiment of the invention;

1 shows a device 1 of a fuel injection system comprising a component 2 for guiding fuel and a connection 3 , the connection unit 4 being connected to a connection partner 5 and a connection provided in the component 2 . It can be formed between the connection partners (6) provided in (3). In this case, FIG. 1 shows the state of the connection unit 4 before assembly, wherein the connection partner 6 on the connection part 3 is used as the first connection partner 6 and the connection partner 5 on the part 2 is the second A schematic excerpt sectional view according to a first embodiment used as a connection partner 5 is shown.

The part 2 can in particular be formed as a fuel distributor rail 2 . The connection 3 can be formed as a sensor 3 . A sensor element 7 can be provided, which in the assembled state measures the pressure of the fuel, for example located in the axial bore 8 of the connection 3 . This allows the connection 3 to be formed as a pressure sensor 3 . However, other sensor functions can also be implemented, for example temperature measurement. The pressure of gasoline as fuel may be, for example, 35 MPa.

An external thread 9 is formed on the first connecting partner 6 . Furthermore, the second connection partner 5 has an internal thread 10 by which the first connection partner 6 can be screwed into the second connection partner 5 . A screw connection 11 is provided by means of an external thread 9 and an internal thread 10 . The connection partners 5 , 6 in this case are in relation to the shaft 12 by means of a screw connection so that the connection partner 6 is engageable into the recess 14 of the connection partner 5 in the engagement direction 13 . so they can be connected to each other.

A conical sealing surface 15 is formed on the connecting partner 6 . The cone angle 16 of the conical sealing face 15 is in this case selected in the range of approximately 60° to approximately 120°.

A partly conical face 17 is formed on the connecting partner 5 , which leads to a peripheral riser 18 . A sealing profile 19 is realized in the connection partner 5 by means of the conical face 17 and the raised portion 18 . A peripheral riser 18 extends around the axis 12 . The peripheral riser 18 faces the conical sealing face 15 of the connecting partner 6 . Furthermore, the conical sealing surface 17 of the connecting partner 5 faces the conical sealing surface 15 of the connecting partner 6 . The sealing contour 19 of the connection partner 5 is formed by the raised portion 18 of the second connection partner 5 deformed at least partially in the screwed state and the conical sealing surface 15 of the first connection partner 6 . ), the peripheral elevation 18 of the second connection partner 5 is partially plastically deformed upon screwing the second connection partner 5 and the first connection partner 6 in order to form a metal seal between them. do. This process will continue to be described with reference to FIG. 2 .

FIG. 2 shows according to a first embodiment of the invention a part of the connecting unit 4 marked with II in FIG. 1 during assembly. In this case, the connection partner 6 is shown in contact with the riser 18 directly at the contact point 21 or at the peripheral contact line 21 due to its angular position 20 . When further screwing is made, plastic deformation of the raised portion 18 appears. This may take, for example, the final position indicated by the line 12 shown in dashed lines. The final position of the connection partner 6 relative to the connection partner 5 can in this case be determined by means of the line 22 , said final position corresponding to the maximum settable plastic deformation of the peripheral riser 18 , this In this case, only partial plastic deformation of the rising portion 18 appears. The riser 18 is suitably formed for this purpose.

In the deformed state of the riser 18, an effective sealing surface 23 occurs with the position indicated by the line 22 in FIG. This effective sealing surface 23 is formed between the conical sealing surface 15 and the plastically deformed rise 18 . The structural size of the sealing surface 23 can be set at least approximately by the rotation angle position 20 .

This allows the formation of a metallic seal between the connecting partners 5 , 6 between the raised portion 18 partially deformed in the screwed state and the conical sealing face 15 . The riser 18 is in this case spherical and/or toric in its initial state. In particular, the peripheral rise 18 of the connection partner 5 may comprise a rounded transition 24 for the axial through bore 25 of the connection partner 5 . The rounded transition 24 may be implemented with a radius R in this case.

The material pair between the connecting partners 5 , 6 is predetermined such that only plastic deformation of the raised portion 18 and no plastic deformation of the conical sealing face 15 occur. Thereby, in the assembled state, the sealing area 23 provided by the effective sealing surface 23 is formed as a conical sealing area 23 , said sealing area 23 having the same conical angle 16 as the conical sealing surface 15 . ) has This is because the cone angle 16 of the sealing area 23 is in this case predetermined by the conical sealing surface 15 of the first connecting partner 6 . The cone angle 16 of the sealing area 23 is thereby also within the range of approximately 60° to approximately 120°. The cone angle 26 of the conical face 17 of the sealing contour 19 of the connection partner 5 is preferably predetermined to be greater than the cone angle 16 .

A (central) sealing sheet width 27 is formed in the deformed rise 18 between the connecting partners 5 , 6 from the effective sealing surface (sealing area) 23 . The sealing sheet width 27 can in this case also be set by the angle of rotation (angle position) 20 between the connecting partners 5 , 6 .

In this embodiment the first connection partner 6 is formed as a bolt 6 with an axial bore 8 . The second connection partner 5 is formed as a socket 5 with an axial through bore 25 .

FIG. 3 shows a part of the connecting unit 4 indicated by II in FIG. 1 according to a second embodiment. In this embodiment a first connection partner 6 is provided for the component 2 , while a second connection partner 5 is provided for the connection 3 . A plastically deformable rise 18 is thereby formed in the connecting partner 5 of the connecting part 3 . A conical sealing surface 15 , which is preferably not plastically deformed during the formation of the connection, is formed on the connection partner 6 of the part 2 . Thus in this embodiment the first connection partner 6 can be formed as a socket with an axial through bore 25 , and the second connection partner 5 as a bolt 5 with an axial bore 8 . can be formed.

The present invention is not limited to the above-described embodiments.

4 connection unit
5 Second connection partner
6 1st connection partner
15 conical sealing face
18 rise
19 sealing configuration

Claims (11)

A metal sealing connection unit (4), comprising:
The connection unit comprises a first metal connection partner 6 and a second metal connection partner 5 , the metal connection partners 5 , 6 being able to be connected to each other with respect to the shaft 12 by means of a screw connection and , a sealing contour assigned to the conical sealing surface 15 of the first connection partner 6 , wherein the first connection partner 6 is formed with a conical sealing surface 15 and the second connection partner 5 is assigned to the conical sealing surface 15 of the first connection partner 6 , 19 ) is formed, the sealing contour 19 of the second connecting partner 5 having a peripheral elevation 18 extending around the axis 12 in the initial state, the elevation 18 being the Facing the conical sealing surface 15 of the first connection partner 6 , the sealing contour 19 of the second connection partner 5 is at least partially deformed in the screwed state. ) of the second connecting partner 5 and the first connecting partner 6 to form a metallic seal between the raised portion 18 of the The peripheral elevation 18 of the second connection partner 5 is formed to be at least partially plastically deformed upon screwing, and the peripheral elevation 18 of the second connection partner 5 comprises: 18) Connection unit, characterized in that it is formed such that only a partial plastic deformation of the raised portion (18) of the sealing contour (19) occurs during the maximum settable plastic deformation of 18). Connection unit according to claim 1, characterized in that the peripheral riser (18) is formed as a sphere and/or a torus. 3. The method according to claim 1 or 2, characterized in that the plastic deformation between the first connection partner (6) and the second connection partner (5) appears only in the contour (19) of the second connection partner (5). connecting unit. The cone according to claim 1 or 2, defined by the conical sealing surface (15) of the first connection partner (6) by plastic deformation of the sealing contour (19) of the second connection partner (5). Connection unit, characterized in that a conical sealing area (23) with an angle (16) is formed. Connection unit according to claim 1 or 2, characterized in that the cone angle (16) of the conical sealing surface (15) is selected in the range of 60° to 120°. 3. The method according to claim 1 or 2, wherein the screw connection between the first connection partner (6) and the second connection partner (5) is such that the first connection partner (6) and the second connection partner (5) ) that the sealing sheet width 27 is formed so as to be settable by the angle of rotation 20 between the first and second connecting partners 6 and 5. Connecting unit characterized. Connection unit according to claim 1 or 2, characterized in that the peripheral rise (18) of the second connection partner (5) has a rounded transition (24) to the axial through bore (25). delete 3. The first connection partner (6) according to claim 1 or 2, wherein the first connection partner (6) is formed as a bolt (6) with an axial bore (8), and the second connection partner (5) has an axial through bore (25). ), or the first connection partner 6 is formed as a socket 6 with an axial through bore 25, and the second connection partner 5 has an axial bore A connecting unit, characterized in that it is formed as a bolt (5) with (8). Device (1) of a fuel injection system comprising a component (2) for guiding fuel and a connection (3), wherein a metal sealing connection of a unit (4) according to claim 1 or 2 is provided, said connection comprising: A device enabling the connection of a connection partner (6; 5) provided on the connection part (3) with a connection partner (5; 6) provided on the part (2). Device according to claim 10, characterized in that the connection (3) comprises a sensor (7) and/or a pressure sensor (7).

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