Tappet Bridge Piece Radial Clamping for Fuel Pump Noise
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Solution Overview
Problem
Existing tappets for high-pressure fuel pumps suffer from noise emissions due to axial and radial mobility of the bridge piece, inability to withstand high loads, and restricted media passage.
Innovation Solution
The bridge piece is securely held in the housing by a snap ring in an axially and radially tensioned manner without play, using bent hook-like ends or wedges for radial bracing, allowing for a thicker design that enhances load-bearing capacity and media flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the bridge piece is made thinner to fit within the housing, then the housing can accommodate the bridge piece, but the bridge piece cannot withstand high loads and produces noise due to mobility
Solution Approach 1:
The bridge piece is segmented into a thin-walled tubular structure with longitudinal ribs, dividing the load-bearing function across multiple structural elements rather than requiring a solid thick cross-section
Solution Approach 2:
The bridge piece combines thin-walled construction with integrated longitudinal ribs to create a composite structural system that achieves high stiffness and load-bearing capacity despite reduced material volume
2Strength
If the bridge piece is made thicker to withstand high loads, then the load-bearing capacity increases, but the bridge piece cannot be mounted in the housing and media passage is restricted
Solution Approach 1:
The bridge piece uses a thin-walled tubular design with longitudinal ribs that segment the structure into load-bearing elements, achieving high strength without increased overall thickness
Solution Approach 2:
Instead of increasing thickness in the radial dimension, the bridge piece derives strength from longitudinal ribs that extend along the length of the tube, utilizing the longitudinal dimension to compensate for reduced radial thickness
3Strength
If the bridge piece radially fills the tappet to increase strength, then load-bearing capacity improves, but media passage through the tappet deteriorates
Solution Approach 1:
The thin-walled tubular bridge piece acts as a flexible yet strong structure that maintains structural integrity while leaving sufficient radial clearance for media flow around the component
Solution Approach 2:
The bridge piece derives its strength from longitudinal ribs extending along the tube length rather than from radial thickness, allowing the radial dimension to be minimized for optimal media passage while maintaining load-bearing capacity through longitudinal structural elements
4Adaptability or versatility
If the bridge piece is allowed to move axially and radially to accommodate thermal expansion and manufacturing tolerances, then adaptability improves, but noise emissions and rattling increase
Solution Approach 1:
The retaining ring applies preliminary radial clamping force to the bridge piece, preventing unwanted axial and radial movements before they can generate noise or rattling during operation
Solution Approach 2:
The retaining ring creates a pre-stressed state in the bridge piece, changing the mechanical parameters (clamping force, contact pressure) to eliminate play and noise while maintaining the ability to accommodate thermal expansion and manufacturing tolerances
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 eliminates noise issues, supports high loads, and increases media passage volume, ensuring a quieter and more efficient operation of high-pressure fuel pumps.
Implementation Method 1
the snap ring (12) on the inner shell (8) fixed retaining ring... held in the housing by the retaining ring in an axially and radially tensioned manner without play... snapping ends of the securing ring bent like a hook in the axial direction of the plunger
Data Source
Figure 1~2
Figure 3~5
AI summary
A tappet (1) for a high-pressure fuel pump of an internal combustion engine is proposed, having a tube-like housing (2), in the case of the drive-side annular face (3) of which two flats (5) which are recessed from an outer shell (4) of the housing (2) lie diametrically opposite one another, in which flats a pin (7) is mounted which supports a roller (6), wherein, axially below the roller (6), an inner shell (8) of the housing (2) is penetrated by a separate bridge piece (9), the output-side face (10) of which acts as a rest for a tappet follower part and which bears axially firstly in the direction of the drive-side annular face (3) against undersides (13) of the flats (5) and secondly in the direction of an output-side annular face (11) of the housing (2) by way of a securing ring (12) which is fixed on the inner shell (8), wherein the bridge piece (9) is held by the securing ring (12) such that it is clamped axially and radially without play in the housing (2).