Fuel Injection Device End Face Structuring for Torque Transmission
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Solution Overview
Problem
Existing fuel injection devices for internal combustion engines face limitations in maximum permissible tightening torque and nominal pressure due to the strength of locking pins, which also incur high costs and complex anti-rotation mechanisms.
Innovation Solution
The fuel injection device increases the coefficient of friction between components by structuring the end faces with ring sector-shaped segments and grooves, allowing for higher torque transmission without relative rotation, and optionally uses a locking pin for additional anti-twist functionality, thereby enhancing the maximum transmissible torque and nominal pressure without increasing the hold-down force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If locking pins are used to prevent rotation of components during tightening, then anti-rotation function is achieved, but the maximum permissible tightening torque is limited by the strength of the locking pins and costs increase
Solution Approach 1:
The invention extracts the anti-rotation function from the locking pin system and transfers it to the end face structuring. The grooves and ring sector-shaped segments on the end faces provide the anti-rotation mechanism, allowing the locking pin to be removed or used only as an optional additional element, thereby eliminating the torque limitation imposed by locking pin strength
Solution Approach 2:
The end face structuring with grooves and ring sector-shaped segments acts as an intermediary mechanism that enables torque transmission and anti-rotation without relying on the locking pin. This intermediary structure distributes the torque across the end face contact area, preventing rotation while allowing higher tightening torques
2Ease of operation
If locking pins are used to prevent component rotation, then anti-rotation is achieved, but device complexity and cost increase
Solution Approach 1:
The invention removes the locking pin from the essential anti-rotation mechanism, making it optional rather than mandatory. The end face structuring alone provides sufficient anti-rotation capability, simplifying the overall device structure and reducing component count and cost
Solution Approach 2:
The end faces are designed to automatically prevent rotation through their structured geometry. The grooves and ring sector-shaped segments create mechanical interlocking that self-regulates during tightening, eliminating the need for separate locking mechanisms and reducing device complexity
3Strength
If end faces are structured with grooves and ring sector-shaped segments, then coefficient of friction increases and torque transmission improves, but manufacturing complexity increases
Solution Approach 1:
The end face is segmented into grooves and ring sector-shaped segments, which can be manufactured as standardized features. This segmentation allows the complex structuring to be broken down into repeatable manufacturing operations, reducing overall manufacturing complexity despite the increased surface feature complexity
Solution Approach 2:
The invention changes the surface parameters of the end faces by adding grooves and ring sector-shaped segments with specific geometric parameters. These parameter changes increase the coefficient of friction and torque transmission capability while the parameters are designed to be achievable with standard manufacturing processes
4Strength
If maximum permissible tightening torque is increased without increasing hold-down force, then nominal pressure increases, but component rotation during tightening occurs
Solution Approach 1:
The invention replaces the mechanical locking system (locking pins) with a friction-based system enhanced by end face structuring. The grooves and ring sector-shaped segments increase the coefficient of friction, allowing higher torque transmission while preventing rotation through frictional forces rather than mechanical interlocking
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively increases the maximum permissible tightening torque and nominal pressure of the fuel injection device, reducing the need for excessive hold-down force and allowing for higher pressure sealing within the device, while maintaining assembly precision and preventing component rotation during tightening.
Implementation Method 1
The structuring increases the coefficient of friction, especially the coefficient of static friction, in the contact of the first component with the second component, so that the maximum transferrable tightening torque of the clamping nut - with a constant hold-down force on the first and second component - is increased
Data Source
AI summary
Fuel injection device (100) for injecting fuel into a combustion chamber of an internal combustion engine, comprising a first component (1) and a second component (2; 2') axially screwed together by a clamping nut (5), the clamping nut (5) being in threaded engagement with the first component (1) such that a first end face (1a) formed on the first component (1) is pressed together with a second end face (2a; 2a') formed on the second component (2; 2'). At least the first end face (1a) is structured such that no rotation of the first component (1) and second component (2; 2') occurs during tightening of the clamping nut (5).