CN107110087B

CN107110087B - Device for fuel injection system and metal-sealed connecting assembly

Info

Publication number: CN107110087B
Application number: CN201580070390.2A
Authority: CN
Inventors: K·朗; G·赫克; N·席尔霍尔茨
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2014-12-22
Filing date: 2015-10-26
Publication date: 2021-04-27
Anticipated expiration: 2035-10-26
Also published as: DE102014226819A1; CN107110087A; ES2838806T3; EP3237746A1; KR102447585B1; WO2016102104A1; PL3237746T3; EP3237746B1; KR20170095886A

Abstract

The invention relates to a metal-sealed connecting assembly (4). The device of the fuel injection system has a fuel-conducting part (2) and a connecting piece (3). The connecting assembly comprises a first metallic connecting partner (6) and a second metallic connecting partner (5). The metallic connection partners (5, 6) can be connected to one another about an axis (12) in such a way that a conical sealing surface (15) is formed on the first connection partner (6), wherein a sealing contour (19) associated with the conical sealing surface (15) of the first connection partner (6) is formed on the second connection partner (5). The sealing contour (19) of the second connection partner (5) has, in an initial state, a bead (18) which runs around the axis (12) and faces the conical sealing surface (15) of the first connection partner (6), wherein the sealing contour (19) of the second connection partner (5) is configured in such a way that, when the first connection partner (6) is screwed together with the second connection partner (5), the running bead (18) of the second connection partner (5) is at least partially plastically deformed in order to form a metallic seal between the conical sealing surface (15) of the first connection partner (6) and the at least partially deformed bead (18) of the second connection partner (5) in the screwed-together state.

Description

Device for fuel injection system and metal-sealed connecting assembly

Technical Field

The invention relates to a metal-sealed connecting arrangement and to a device for a fuel injection system having a metal-sealed connecting arrangement. The invention relates in particular to the field of fuel injection devices for internal combustion engines.

Background

A rail assembly of a fuel injection system is known from DE 102008035492 a 1. The rail assembly is used in particular for internal combustion engines of motor vehicles. In this case, a supply line is provided for supplying and supplying the fuel under pressure, and a plurality of branches fastened to the supply line are provided for the fluid connection of the supply line to in each case one fuel injector. Furthermore, the supply tube has an inner contour on its axial end, into which the pressure sensor connection is inserted, which inner contour is of conical shape, complementary to the outer contour of the use section. In this case, the conical inner contour with the outwardly expanding inner cross section can also be formed by axially pressing in the use section. This ensures that the inner contour of the supply pipe is shaped exactly complementary to the outer contour of the use section.

The rail assembly known from DE 102008035492 a1 and the connection provided therein, which is designed by axial pressing, have the following disadvantages: the pretension generated on this connection is not determined to a large extent. In particular, very high forces can occur here by axial pressing, which requires a corresponding design of the connection partners. Since the cone angle of the conical inner contour is very small, the occurring tensile forces can become very fast and very large, so that a corresponding plasticity of the supply tube has to be ensured.

The use of a threaded connection can be considered when forming the connection of the pressure sensor to the fuel storage device. Ball/cone or cone/cone connection pairings with moving contact surfaces can be considered here. Here, a threaded connection with a defined torque is possible, wherein the interface is sealed by surface contact. Depending on the material pairing and the geometric tolerances, a plastic deformation of only one connection partner or of both connection partners takes place. However, this causes problems: by controlling the torque of the assembly, large deviations in the sealing position behavior may occur due to various influences. The important influence here is the deviation of the friction coefficient. This is particularly disadvantageous, since a very high safety factor must be applied in the design of the connection partners in order to ensure a minimum deformation or pretensioning force.

Disclosure of Invention

In contrast, the invention proposes a metal-sealed connecting arrangement, in particular for a fuel injection system of an internal combustion engine, having a first metal connecting partner which can be connected to one another by screwing about an axis, wherein a conical sealing surface is formed on the first connecting partner, wherein a sealing contour associated with the conical sealing surface of the first connecting partner is formed on the second connecting partner, wherein the sealing contour of the second connecting partner has, in an initial state, a bulge which runs around the axis and faces the conical sealing surface of the first connecting partner, wherein the sealing contour of the second connecting partner is configured such that, when the first connecting partner is screwed to the second connecting partner, the circumferential bead of the second connection partner is at least partially plastically deformed in order to form a metal seal between the conical sealing surface of the first connection partner and the at least partially deformed bead of the second connection partner in the tightened state.

According to the invention, a device for a fuel injection system is also proposed, having a fuel-conducting component and a connecting piece, wherein a metal-tight connection assembly according to the invention is provided, which enables a connection of a connection partner provided on the component to a connection partner provided on the connecting piece.

The metal seal connection assembly and the fuel injection device of the present invention have the advantages that: improved configuration and functional manner can be achieved. In particular, an improved sealing action can be achieved with respect to a given material usage. In particular, the power density can be increased here with the same installation space, so that sealing can take place against higher pressures. Accordingly, material usage can be reduced to meet the predetermined requirements. This also makes it possible to realize a sealing function at low cost, in which case the fuel-conducting component, in particular the internal pressure of the fuel distributor, can be sealed off.

The metal-sealing connection assembly according to the invention and the device according to the invention for a fuel injection system can be realized by the measures mentioned in the preferred embodiments.

In particular, it can be used in a fuel injection device for gasoline direct injection in which an air-fuel mixture is formed in a cylinder combustion chamber of an internal combustion engine configured as a gasoline engine. For this purpose, fuel is injected into the combustion chamber at a high pressure. The fuel distribution device can be used here as a pressure accumulator and for distributing fuel to a plurality of fuel injection valves. For controlling, in particular regulating, the pressure in the injection system, a sensor can be used, which can at least make a pressure measurement and is preferably configured as a high-pressure sensor.

Special requirements arise in particular for the connection of such a pressure sensor to a fuel distribution rail for direct gasoline injection if a threaded connection is to be realized. A connecting counterpart can be a screw-in nipple which has a sealing function and guides the internal pressure. In the other connection partner, the pretensioning force cannot be maintained by the screw head but by the sealing cone. However, large deviations in the sealing position behavior occur in the case of a possible screwing-in with a defined torque, which is caused in particular by deviations in the coefficient of friction. Thus, in contrast to this, it is advantageous: the screwing-in depth or the spacing of the connection partners beside the sealing position is adjusted.

In this case, a seal can advantageously be achieved at the metal interface between one connection partner, for example a base body of the fuel storage device, and the other connection partner, for example a mounting part. The metal connection can be characterized by a rotating screw with a thread and a conical sealing surface, an upright nut with a thread and a spherical or toroidal (torisch) sealing seat, a relative movement caused by the rotational movement of the two connection partners (sealing partners) during screwing in of the screw, and a plastic deformation of the one connection partner due to the pretensioning force for the fuel seal.

In a possible variant, a spherical or toroidal bolt and a conical nut can also be used. Furthermore, the mounting in the sealing position can be a sensor. Furthermore, only plastic deformation can occur on the pressure sensor socket by means of suitable material pairing. The width of the sealing seat can be adjusted in a targeted manner during the initial assembly of the interface by means of an assembly method which controls the rotation angle. The bolts provided can be configured to guide the internal pressure. The taper angle on the bolt can be between about 60 degrees and about 120 degrees. Furthermore, the radius on the nut side can be configured in such a way that it does not deform completely plastic even when the contact pressure is at its maximum.

Therefore, in the formation of a metal-sealed connection assembly, it is advantageous: the circumferential bead is shaped in the form of a sphere and/or a torus. In this case, a configuration corresponding to the partial shape of the torus, in particular a convex configuration, is provided in the case of a torus-shaped formation. The spherical configuration is generally part-shaped as a torus. Thus, a molding is possible in which the plastic deformation of the second connection partner is limited to the encircling bead. Furthermore, an advantageous circumferential seal can be achieved by: the sealing contour is specifically adjusted by plastic deformation to an at least approximately predetermined size of the sealing surface produced. It is therefore also advantageous: plastic deformation between the first and second connection partners occurs only on the sealing contour of the second connection partner.

In particular, it is advantageous here that: the circumferential bead of the second connection partner is configured in such a way that, at the maximum adjustable plastic deformation of the circumferential bead, only a partial plastic deformation of the bead occurs. The threaded connection between the first and second connection partners can be advantageously configured in such a way that the width of the sealing seat on the projection deformed between the first and second connection partners can be adjusted by the angle of rotation between the first and second connection partners. The degree of plastic deformation of the sealing contour of the second connection partner is also specified here by the specified angle of rotation.

Advantageously, the conical sealing region is also formed by plastic deformation of the sealing contour of the second connection partner. Wherein the conical sealing region is formed with a cone angle, which is defined by the conical sealing surface of the first connection partner. This enables a desired effective sealing surface, in particular the size of the sealing surface, to be reliably adjusted. A certain independence from possible manufacturing tolerances and deviations of the coefficient of friction is also obtained here.

In one possible embodiment, it is advantageous: the first connection partner is configured as a screw with an axial bore, and the second connection partner is configured as a connection piece with an axial through-bore. Here, too, the axial bore or the axial through-hole is configured "axially" only with respect to the sealing region and not necessarily with respect to the entire component. In another possible embodiment, it is advantageous: the first connection partner is designed as a connection piece having an axial through-opening, and the second connection partner is designed as a screw having an axial bore. In this way, depending on the application, a plastic deformation can be achieved in a targeted manner on only one of the connection partners, specifically for the attachment of a sensor, in particular a pressure sensor.

The advantages are thus also obtained: at the start of the screwing, there is a defined contact point or a defined contact line all around. In tests it has been shown that: in the case of material pairings, which are mainly of similar steel, for example corrosion-resistant steel, cold welds sometimes occur on the sealing cone. This can be explained in particular by locally high stresses at the edges of the chamfers provided. This is counteracted in particular by a spherical or toroidal sealing contour on the seat, since a more uniform stress rise is thereby achieved.

The plastic deformation can be set precisely and largely independently of friction within the desired order of magnitude by means of an optimized assembly process. A further advantage is that the thread strength can be used better by means of an optimized assembly process, since smaller deviations from the maximum thread stress can be achieved by means of smaller deviations in the pretensioning force.

In an advantageous manner, a metal-sealing, rotationally fixed, modified ball/cone connection in the contact region can be realized after assembly, wherein the sealing contour in the contact region is shaped like a sphere or torus, so that the "ball" is modified or changed in the shape of a sphere to a part of a torus. Depending on the material pairing, the sealing contour is plastically deformed during the screwing-in process, whereas the first connection partner is not plastically deformed, in particular in its contact region facing the sealing contour. A conical sealing region with a cone angle, which is defined by the first connection partner, is formed by plastic deformation of the sealing contour of the second connection partner. The required sealing length and the pretensioning force can be set very precisely by forming the conical region. This is achieved in particular by means of an assembly method which controls the angle of rotation and by means of a geometric relationship between the thread pitch and the angle of rotation.

Drawings

In the following description, preferred embodiments of the present invention are explained in detail with reference to the drawings, in which corresponding elements are provided with consistent reference numerals.

Fig. 1 shows, in a simplified schematic cross-sectional view corresponding to a first embodiment of the invention, an arrangement of a fuel injection device with a connection assembly before assembly;

fig. 2 shows a partial section of the connecting assembly, indicated with II in fig. 1, in accordance with a first embodiment of the invention; and

fig. 3 shows a partial section of a connecting assembly, which is designated II in fig. 1, according to a second exemplary embodiment of the invention.

Detailed Description

Fig. 1 shows a device of a fuel injection system with a fuel-conducting component 2 and a connecting piece 3, wherein a connecting arrangement 4 can be set up between a connecting partner 5 arranged on the component 2 and a connecting partner 6 arranged on the connecting piece 3. Fig. 1 shows a simplified schematic cross-sectional illustration of the connecting assembly 4 in a state before assembly, in which the connecting partner 6 on the connecting piece 3 serves as a first connecting partner 6 and the connecting partner 5 on the component 2 serves as a second connecting partner 6.

The component 2 can be configured in particular as a fuel distribution rail 2. The connecting element 3 can be configured as a sensor 3. For this purpose, a sensor element 7 can be provided, which in the assembled state measures, for example, the fuel pressure prevailing in an axial bore 8 of the connection piece 3. The connecting element 3 can thus be configured as a pressure sensor 3. However, other sensor functions, such as temperature measurement, can also be implemented. The pressure of the gasoline as possible fuel can be 35Mpa, for example.

An external thread 9 is formed on the first connection partner 6. Furthermore, the second connection partner 5 has an internal thread 10, by means of which the first connection partner 6 can be screwed into the second connection partner 5. The threaded connection 11 is provided by the external thread 9 and the internal thread 10. The connection partners 5,6 can be connected to one another by screwing about the axis 12 in such a way that the connection partners 6 can engage in the groove 14 of the connection partners 5 in the engagement direction 13.

A conical sealing surface 15 is formed on the connection partner 6. The cone angle 16 of the conical sealing surface 15 is selected from the range of about 60 degrees to about 120 degrees.

A partially conical surface 17 is formed on the connection partner 5, which surface merges into a circumferential bead 18. A sealing contour 19 is realized on the connection partner 5 by the conical surface 17 and the bulge 18. The protuberance 18 encircles about the axis 12. The circumferential bead 18 faces the conical sealing surface 15 of the connection partner 6. Furthermore, the conical sealing surface 17 of the connection partner 5 also faces the conical sealing surface 15 of the connection partner 6. The sealing contour 19 of the connection partner 5 is configured in such a way that, when the first connection partner 6 is screwed together with the second connection partner 5, the circumferential bead 18 of the second connection partner 5 is partially plastically deformed, so that a metallic seal is formed between the conical sealing surface 15 of the first connection partner 6 and the at least partially deformed bead 18 of the second connection partner 5 in the screwed-together state. The process is described in detail below also with reference to fig. 2.

Fig. 2 shows a detail of the connecting assembly 4, which is designated II in fig. 1, during assembly, in accordance with a first exemplary embodiment of the invention. The connection partner 6 is shown in a state in which it, due to its angular position 20, strikes the projection 18 exactly at the contact point 21 or the circumferential contact line 21. The bulge 18 is plastically deformed when tightening is continued. Thus, for example, a final position can be assumed, which is illustrated by the dashed line 22. In this case, the final position of the connection partner 6 relative to the connection partner 5 can be determined by the line 22, which corresponds to the maximum adjustable plastic deformation of the circumferential bead 18, wherein only a partial plastic deformation of the bead 18 occurs. The bulge 18 is suitably configured for this purpose.

In the deformed state of the bead 18, an effective sealing surface 23 is then produced, the position of which on the line 22 is illustrated in fig. 2. The effective sealing surface 23 is produced between the conical sealing surface 15 and the plastically deformed bulge 18. The geometry of the sealing surface 23 can be adjusted at least approximately by the angular position 20.

A metal seal can thus be formed between the

connection partners

5,6 between the conical sealing surface 15 and the bulge 18 which is partially deformed in the tightened state. In this case, the elevations 18 are shaped in the initial state as spheres and/or torus shapes. In particular, the circumferential bead 18 of the connection partner 5 can have a rounded transition 24 to the axial through-opening 25 of the connection partner 5. The rounded transition 24 can be embodied with a radius R.

The material pairing between the

connection partners

5,6 is arranged such that only plastic deformation of the bulge 18 occurs and no plastic deformation of the conical sealing surface 15 occurs. The sealing area 23, which is defined by the effective sealing surface 23 in the assembled state, is thus designed as a conical sealing area 23 having the same cone angle 16 as the conical sealing surface 15. Since the conical angle 16 of the sealing region 23 is defined by the conical sealing surface 15 of the first connection partner 6. Thus, the cone angle 16 of the sealing area 23 is in the range from about 60 degrees to about 120 degrees. Preferably, the cone angle 26 of the conical surface 17 of the sealing contour 19 of the connection partner 5 is defined to be greater than the cone angle 16.

The effective sealing surface (sealing area) 23 results in an (average) sealing seat width 27 between the

connection partners

5,6 over the deformation ridge 18. The seal seat width 27 can likewise be adjusted by the angle of rotation (angle of rotation) 20 between the

connection partners

5, 6.

In this exemplary embodiment, the first connection partner 6 is designed as a screw 6 with an axial bore 8. The second connection partner 5 is designed as a connection piece 5 with an axial through-hole 25.

Fig. 3 shows a detail of the connecting assembly 4, which detail is denoted by II in fig. 1, according to a second exemplary embodiment of the invention. In this embodiment, the first connection partner 6 is arranged on the part 2, while the second connection partner 5 is arranged on the connecting piece 3. The plastically deformable bulge 18 is thus formed on the connection partner 5 of the connection element 3. A conical sealing surface 15 is formed on the connection partner 6 of the component 2, which conical sealing surface is preferably not plastically deformed when the connection is being made. In this embodiment, the first connection partner 6 can therefore be configured as a socket with an axial through-hole 25, and the second connection partner 5 can be configured as a bolt 5 with an axial hole 8.

The invention is not limited to the described embodiments.

Claims

1. Metal-sealed connecting arrangement (4) having a pressure sensor (3) as a first metallic connecting partner (6) and having a fuel distribution strip (2) as a second metallic connecting partner (5), wherein the first connecting partner (6) and the second connecting partner (5) are part of a fuel injection system of an internal combustion engine, wherein a conical sealing surface (15) is formed on the first connecting partner (6), characterized in that the first connecting partner (6) and the second connecting partner (5) can be directly connected to one another by screwing together about an axis (12), wherein a sealing contour (19) associated with the conical sealing surface (15) of the first connecting partner (6) is formed on the second connecting partner (5), wherein the sealing contour (19) of the second connecting partner (5) has an initial state about the axis (12) ) A circumferential bead (18) which faces the conical sealing surface (15) of the first connection partner (6), wherein the sealing contour (19) of the second connection partner (5) is configured in such a way that, when the first connection partner (6) is screwed to the second connection partner (5), the circumferential bead (18) of the second connection partner (5) is at least partially plastically deformed in order to form a metallic seal between the conical sealing surface (15) of the first connection partner (6) and the circumferential bead (18) of the second connection partner (5) which is at least partially deformed in the screwed-on state.

2. A connecting assembly according to claim 1, characterized in that the encircling elevation (18) is shaped as a sphere or a torus.

3. A connecting assembly according to claim 1 or 2, characterized in that plastic deformation between the first and second connecting partners (6, 5) occurs only on the sealing contour (19) of the second connecting partner (5).

4. A connection assembly according to claim 1 or 2, characterised in that a conical sealing area (23) with a cone angle (16) prescribed by the conical sealing surface (15) of the first connection counterpart (6) is formed by plastic deformation of the sealing profile (19) of the second connection counterpart (5).

5. A connection assembly according to claim 1 or 2, characterized in that the cone angle (16) of the conical sealing surface (15) is selected from the range of 60 to 120 degrees.

6. The connecting assembly according to claim 1 or 2, characterized in that the screwing between the first connecting partner (6) and the second connecting partner (5) is configured such that the sealing seat width (27) between the first connecting partner (6) and the second connecting partner (5) on the circumferential ridge (18) which is deformed can be adjusted by the angle of rotation (20) between the first connecting partner (6) and the second connecting partner (5).

7. A connection assembly according to claim 1 or 2, characterized in that the encircling elevation (18) of the second connection counterpart (5) has a rounded transition (24) to an axial through hole (25).

8. A connecting assembly according to claim 1 or 2, characterized in that the encircling ridge (18) of the second connecting partner (5) is configured in such a way that, with a maximum adjustable plastic deformation of the encircling ridge (18), only a partial plastic deformation of the encircling ridge (18) of the sealing contour (19) occurs.

9. A connecting assembly according to claim 1 or 2, characterized in that the first connecting partner (6) is configured as a bolt with an axial bore (8), the second connecting partner (5) is configured as a nipple with an axial through-bore (25); alternatively, the first connection partner (6) is configured as a connection piece having an axial through-opening (25), and the second connection partner (5) is configured as a screw having an axial bore (8).

10. A connecting assembly according to claim 1 or 2, characterised in that it is used in a fuel injection device of an internal combustion engine.

11. Arrangement of a fuel injection system with a fuel-conducting component and a connection piece, wherein a connection assembly (4) according to one of claims 1 to 9 is provided, which enables a connection of a second connection partner (5) provided on the component to a first connection partner (6) provided on the connection piece.

12. Device according to claim 11, characterized in that the connection has a sensor (7).

13. The device according to claim 12, characterized in that the sensor (7) is a pressure sensor.