DE102009057176A1 - Method for the autofrettage of a component such as a connection strip for injecting system with a wall and a cavity surrounded by the wall, comprises equipping an endangered area of the component with a reinforcing element - Google Patents

Abstract

The method for the autofrettage of a component (1) such as a connection strip for injecting system with a wall and a cavity surrounded by the wall, comprises equipping an endangered area (4) of the component that is resisted for the component of determined operating pressure, for the autofrettage process with a reinforcing element, which is a clamping ring or a clamping bush. The clamping ring or the clamping bush has two hollow-cylindrical shaped half cells, which are connected with a joining means such as quick-release fastener or a bolted connection. The method for the autofrettage of a component (1) such as a connection strip for injecting system with a wall and a cavity surrounded by the wall, comprises equipping an endangered area (4) of the component that is resisted for the component of determined operating pressure, for the autofrettage process with a reinforcing element, which is a clamping ring or a clamping bush. The clamping ring or the clamping bush has two hollow-cylindrical shaped half cells, which are connected with a joining means such as quick-release fastener or a bolted connection. A number of the reinforcing elements is attached for the autofrettage process on the component. The reinforcement elements are removed after the autofrettage process from the component.

Description

The present invention relates to a method for autofrettage of a component according to the preamble of claim 1.

Manifolds CR (so-called Rails) are exposed during operation to a high pulsating pressure (currently up to about 1800 bar). This places high demands on the fatigue strength of the rail. To increase the fatigue strength, the rails are autofretted. When autofretting the rail is exposed inside (high pressure area) for about 5 s to a pressure of about 7000 bar. As a result, internal compressive stresses are generated in the rail material, which counteract the tensile stresses resulting from the operating pressure.

For the rail to survive this unique autofrettage pressure without deformation, it must have sufficient rail wall thickness. However, the wall thickness is clearly oversized for the later operating pressure. Due to this oversizing, the rail weight and the rail raw part costs increase (forging).

The tightening of the exhaust gas regulations (EU6, EU7 ...) requires in the medium term an increase of the injection pressure with diesel engines of z. Currently approx. 1800 bar to approx. 2200 bar and more. Due to the increasing injection pressure, the rail is subject to higher loads and must therefore be autofretted accordingly with higher pressure (up to approx. 10,000 bar). As a result, the rail is always thick-walled and thus heavier and more expensive.

Various improved autofrettage methods have become known in the art.

For example, in the DE 100 00 796 B4 or the DE 200 23 235 U1 proposed to fix the pipeline during the Autofrettagevorgangs in a clamping system with one or more holding means fixed. This "straitjacket" is intended to ensure that a tube performance curve designed with bends or bends is maintained as precisely as possible during the autofrettage process. Indirectly, this also achieves a material saving, since, for example, short pipelines in their specific environment no longer have to be installed with great prestress or by "keeping" the gradient geometry.

In the DE 102 60 856 A1 For example, it is proposed that a component in its cavity during a Druckbeaufschlagungsphase is acted upon with such a pressure that the component is at least partially partially deformed to generate compressive residual stresses in the component and that the component is heated during a temperature treatment phase to a component temperature higher than a room temperature , The thermal treatment is a significantly improved resistance or fatigue strength to high operating pressures and due to large pressure fluctuations to be achieved. Indirectly also a material saving is conceivable because the walls can be made correspondingly thinner.

The method according to DE 102 60 856 A1 However, it is expensive and correspondingly expensive. The process is likely to be difficult to control and very material dependent. The in the DE 100 00 796 B4 or the DE 200 23 235 U1 proposed measures are useless for a substantially straight distribution strip, since such a distribution strip has no curvatures or bends.

The object of the present invention was to propose a method for autofrettage of a metallic component, in particular a distributor strip for injection systems, which allows an embodiment of the component wall thickness on the basis of the expected operating pressure.

According to the invention, it is proposed for this purpose that an endangered area be equipped with a reinforcing element. In this way, regardless of the autofrettage pressure, the wall of the component can only be designed for the operating pressure (eg 1800 instead of 7000 bar) if the component is clamped from outside only for the autofrettage process in the hazardous areas (eg with Clamping rings, clamping jaws, clamping forms, etc.) and thus reinforced. The weight of the component can be reduced accordingly. Lowering the weight of the component also involves a reduction in costs since less material is needed for the component.

Further advantageous embodiments of the invention emerge in particular from the features of the subclaims.

Advantageously, it is provided, for example, that the reinforcing element is a clamping ring or a clamping bush. The above-mentioned elements are particularly suitable for reinforcing the endangered areas, in particular that the homogeneous form of force absorption due to the circular shape is to be expected.

In a further advantageous embodiment of the proposed method can be provided that the clamping ring or the clamping bush has two hollow cylindrical shells. insofar the easy handling of the reinforcing element is ensured. The two half shells can be arranged in a simple manner around the endangered areas and removed again after autofrettage.

To further facilitate the handling and acceleration of the method can be advantageously provided that the half-shells with a connecting means, such as a quick release or a screw connection can be connected.

In a further advantageous embodiment of the method according to the invention can be provided that a number of reinforcing elements for the Autofrettagevorgang be attached to the component. In this respect, the vulnerable areas can be very differentiated, for example, with different reinforcing elements, in particular in terms of size, shape and resilience, are equipped.

Further features and advantages of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings. Show in it

1 a component, in particular a distributor rail common rail, which comes for the inventive method in question;

2 a cross section of the component according to 1 ;

3 a component with a reinforcing element, in particular a clamping ring, for the Autofrettagevorgang;

4 a component with a reinforcing element, in particular a clamping bush, for the Autofrettagevorgang;

5 two half shells of a clamping ring or a clamping bush;

6 a component, in particular a distributor rail common rail, which comes for the inventive method in question.

LIST OF REFERENCE NUMBERS

1

Component (distribution bar)

2

wall

3

cavity

4

endangered area

5

Reinforcement element (clamping ring / clamping bush)

6

shells

First, it will open 1 Referenced.

A component 1 , especially as in 1 illustrated a distribution bar for an injection system, essentially comprises a wall 2 and one through the wall 2 enclosed cavity 3 , Furthermore, the component has 1 endangered areas 4 on. These are areas, although one for the component 1 certain operating pressure, but not pressure, during the autofrettage process. The endangered areas 4 For example, have a lower wall thickness than non-vulnerable areas, which in turn would withstand both the operating pressure, as well as the pressure during the Autofrettagevorgangs.

The endangered areas 4 be used for the autofrettage process with reinforcing elements 5 fitted. In the reinforcing element 5 it is for example a clamping ring. In 3 is an example of a clamping ring (half-sectional view) representative of the reinforcement of all vulnerable areas 4 shown. The clamping ring can be two hollow cylindrical shells 6 have, which can be connected to each other with a suitable connection means (not shown), for example a quick release or a screw connection. This temporary reinforcement allows the component 1 will not be permanently deformed at the endangered cross sections due to the high autofrettage pressure.

While the example according to 3 assumes a scattered attachment of reinforcing elements to a component, is in 6 clearly that the entire component 1 with a reinforcing element 5 can be equipped for the autofrettage process. The component, in particular the distributor strip for an injection system (rail), according to 6 has a constant over the entire Raillänge cross-section. In this respect, the endangered area extends here 4 over the entire component 1 , The reinforcing element 5 is here because of its elongated extension rather than a clamping bush to address, but not in 6 shown.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10000796 B4 [0006, 0008]
• DE 20023235 U1 [0006, 0008]
• DE 10260856 A1 [0007, 0008]

Claims (6)

Method for autofrettage of a component ( 1 ), in particular a distributor strip for injection systems, having a wall ( 2 ) and through the wall ( 2 ) enclosed cavity ( 3 ), characterized in that a vulnerable area ( 4 ) of the component ( 1 ), although that for the component ( 1 ) would withstand certain operating pressure, but not the pressure during the autofrettage process, for the autofrettage process with at least one reinforcing element ( 5 ). A method according to claim 1, characterized in that it is in the reinforcing element ( 5 ) is a clamping ring or a clamping bush. Method according to at least one of the preceding claims, characterized in that the clamping ring or the clamping bush two hollow cylindrical shells ( 6 ) having. Method according to at least one of the preceding claims, characterized in that the half shells ( 6 ) are connectable to a connecting means, such as a quick release or a screw connection. Method according to at least one of the preceding claims, characterized in that a number of reinforcing elements ( 5 ) for the autofrettage process on the component ( 1 ). Method according to at least one of the preceding claims, characterized in that the reinforcing element or elements ( 5 ) after the autofrettage process of the component ( 1 ) are removed.

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