Threaded connection of high-pressure fluid-carrying components of an injection device for internal combustion engines

Patent metadata

Field	Value
Publication number	US-9810352-B2
Application number	US-201313761279-A
Country	US
Kind code	B2
Filing date	Feb 7, 2013
Priority date	Feb 7, 2012
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

In a method for producing a threaded connection between a first component and a second component of an injection device for internal combustion engines, which are each provided for carrying high-pressure fluid, an internal thread is formed on a tubular end portion of the first component, into which the second component can be screwed and clamped against a resting surface of the first component, the second component having formed thereon an external threaded portion for engaging the internal thread of the tubular end portion, an outer ring imparting an elastic prestress acting in the radial direction is pressed onto the tubular end portion, and the components are subsequently screwed together.

First claim

The invention claimed is:

1. A method for producing a threaded connection between a first component that is an integrated high-pressure accumulator of a modular common-rail injector for an internal combustion engine and a second component that is a supporting body of the modular common-rail injector for an internal combustion engine, which components are configured for carrying high-pressure fluid, said method comprising
providing said first component, wherein said first component has a tubular end portion having an interior surface, a resting surface on the interior surface and internal threads formed on another part of the interior surface, the internal threads configured to engage external threads of said second component,
providing said second component, wherein said second component has an external thread configured for threadably engaging the internal threads of the first component and having a separate end face configured for being clamped against the resting surface of the first component after the components are screwed together,
pressing an outer ring onto the tubular end portion of the integrated high-pressure accumulator of a modular common-rail injector to impart an elastic prestress acting in a radial direction onto the tubular end portion,
wherein the elastic prestress imparted by the outer ring imparts a compression between the outer ring and the tubular end portion that is at least 150 N/mm 2 , and
screwing the first and second components together,
wherein the compression imparted between the outer ring and the tubular end portion provides relief to a portion of the threads of the first and second components when the first and second components are threadably screwed together, and the resting surface and the end face are pressed against each other by the compression when the integrated high-pressure accumulator of a modular common-rail injector and the supporting body of the modular common-rail injector are screwed together.

2. A method according to claim 1 , wherein the tubular end portion has a free end and said pressing comprises pressing the outer ring onto the free end of the tubular end portion.

3. A method according to claim 1 , wherein the compression between the outer ring and the tubular end portion is 200-250 N/mm 2 .

4. A threadably connected pair of high-pressure fluid-carrying components of an injection device for an internal combustion engine comprising
a first component that is an integrated high-pressure accumulator of a modular common-rail injector, the first component having a tubular end portion, said tubular end portion comprising an internal thread on a first section and resting surface on a second section; and
a second component that is a supporting body of the modular common-rail injector comprising an external thread screwed into the internal thread for threadably connecting the first component and the second component, the second component having an external end face configured for being clamped against the resting surface of the first component when tightening the threaded connection; and
an outer ring externally fastened to the tubular end portion of said first component by a press fit for imparting an elastic prestress on the tubular end portion in an inward radial direction, wherein the elastic prestress imparted by the outer ring imparts a compression between the outer ring and the tubular end portion that is at least 150 N/mm 2 ,
such that when the first and second components are screwed together the compression imparted between the outer ring and the tubular end portion provides relief to a portion of the threads of the first and second components by which the first and second components are threadably screwed together, and so that the resting surface and the end face are pressed against each other by the compression when the integrated high-pressure accumulator of a modular common-rail injector and the supporting body of the modular common-rail injector are threadably screwed together.

5. A threaded connection according to claim 4 , wherein the tubular end portion includes a free end and the outer ring is fastened to the free end of the tubular end portion.

6. A threadably connected pair of high-pressure fluid-carrying components of an injection device for an internal combustion engine according to claim 4 , wherein the compression between the outer ring and the tubular end portion is 200-250 N/mm 2 .

7. A threadably connected first component and second component of an injection device for internal combustion engines, wherein each component is for carrying high-pressure fluid, said first component is an integrated high-pressure accumulator of a modular common-rail injector and said second component is a supporting body of the modular common-rail injector,
the first component having a tubular end portion having an internal surface; internal threads formed on a section of the interior surface; and a section comprising a resting surface formed on the interior surface, wherein the tubular end portion has a free end;
the second component having an external surface; external threads on a section of the external surface, wherein the external threads are configured for engaging the internal threads in the tubular end portion of the first component, said second component having an unthreaded section of the external surface that is configured for being compressed against the resting surface of the first component;
an outer ring press-fitted over a portion of the tubular end portion to form a compression region imparting an elastic prestress inwardly acting in the radial direction onto the tubular end portion, wherein a region overlaid by the outer press ring comprises a compression region; and
wherein the first and second components are screwed together via the respective internal and external threads, and the free end of the tubular end portion of the first component is not threadably engaged with said second component,
wherein the resting surface is compressed against the unthreaded portion of the exterior surface of the second component by the outer ring,
wherein the compression imparted in the compression region provides stress relief to a portion of the threads of the first and second components by which the first and second components are threadably screwed together, and
wherein the compression between the outer ring and the tubular end portion is at least 150 N/mm 2 .

Assignees

• Bosch Gmbh Robert

Inventors

• Nussbaumer Gernot

Classifications

• Y10T29/49432

  Nozzle making · CPC title

• F02M55/005

  for high pressure conduits, e.g. connected to pump outlet or to injector inlet · CPC title

• F02M47/027 Primary

  Electrically actuated valves draining the chamber to release the closing pressure · CPC title

• F16L15/00 Primary

  Screw-threaded joints; Forms of screw-threads for such joints · CPC title

• F02M2200/03

  Fuel-injection apparatus having means for reducing or avoiding stress, e.g. the stress caused by mechanical force, by fluid pressure or by temperature variations · CPC title