Fuel Pump Holder Damping With Progressive Spring Arms

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Solution Overview

Problem

Existing fuel delivery devices suffer from mechanical damage due to excessive axial deflection caused by external acceleration forces, which is not adequately addressed by current damping elements with non-progressive spring characteristics.

Innovation Solution

Incorporating an elastic spring section that extends in both axial and circumferential directions, connected to the cantilever section of the damping elements, which provides a progressively increasing spring force with axial deflection, reducing the axial deflection of the pump holder and preventing mechanical overload.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If damping elements with non-progressive spring characteristics are used, then structure-borne noise decoupling is achieved, but axial deflection exceeds maximum permissible values causing mechanical damage

Engineering Contradiction:
Improvestructure-borne noise decouplingVSAvoidmechanical damage prevention
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the spring characteristic parameter from non-progressive to strongly progressive. The damping element is designed with a progressive spring characteristic where the spring stiffness increases with deflection amount, allowing it to provide gentle damping at small deflections (maintaining noise decoupling) while providing increasingly stronger resistance at large deflections (preventing mechanical damage).

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The damping element transitions from a static spring characteristic to a dynamic one where the spring force adapts to the deflection amount. The progressive spring characteristic allows the damping element to automatically adjust its damping force based on the magnitude of axial deflection, providing optimal protection across different operating conditions.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If elastic spring arms with axial deflection capability are used, then noise decoupling is improved, but spring arms are subjected to mechanical loads that can cause damage

Engineering Contradiction:
Improvenoise decouplingVSAvoidspring arm durability
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The spring characteristic parameter is changed from linear/non-progressive to strongly progressive. This ensures that the spring force increases disproportionately with deflection, providing adequate protection against mechanical overload while maintaining the necessary deflection capability for noise decoupling.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If axial deflection of pump holder is reduced, then mechanical damage is prevented, but noise decoupling effectiveness may be compromised

Engineering Contradiction:
Improvemechanical damage preventionVSAvoidstructure-borne noise transmission
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The damping element uses a dynamic progressive spring characteristic that adapts to different deflection levels. At small deflections typical of noise vibration, the spring remains compliant allowing effective noise decoupling. At large deflections that could cause damage, the spring becomes progressively stiffer to limit further deflection and protect the pump holder.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring stiffness parameter changes dynamically with deflection amount. The progressive spring characteristic ensures that the damping element provides appropriate compliance for noise isolation while automatically increasing resistance to prevent excessive deflection that would cause mechanical damage.

Inventive Principle:
Principle #35Parameter changes

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 design effectively reduces axial deflection and prevents mechanical damage to the damping elements, while maintaining effective structure-borne noise decoupling and acoustic decoupling, enhancing the durability and performance of the fuel delivery device.

Implementation Method 1

an elastic spring section adjoins the cantilever section, which extends with its longitudinal extent in the axial direction and in the circumferential direction with respect to a pump axis and is connected to the holder

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the damping elements have a strongly progressive spring characteristic during axial deflection, so that with increasing spring deflection of the pump holder a progressively increasing spring force is produced in the damping element

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 3

The damping elements dampen the transmission of structure-borne noise from the conveyor unit to the adjacent components

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP2494181B1Device for delivering fuel
Publication Date: 2014.08.13 ROBERT BOSCH GMBH
  • EP2494181B1 patent drawingFigure 1
  • EP2494181B1 patent drawingFigure 2
  • EP2494181B1 patent drawingFigure 3

AI summary

Devices for conveying fuel are known having a conveying assembly and a pump holder holding the conveying assembly which has a receptacle for the conveying assembly and a holder connected to the receptacle via three damping elements. The damping elements damp the structure-born noise transmission from the conveying assembly to the adjacent components. The damping elements each have a cantilever section which projects starting from the receptacle into the region of the holder and runs in the radial direction and circumferential direction. The cantilever sections are designed as elastic spring arms, the axial deflection thereof in respect of a pump axis being able to exceed a maximum allowable value by means of external acceleration forces. The mechanical stresses occurring in the spring arms can lead to damage to the spring arms. In the device according to the invention, the damping elements have a strongly progressive spring characteristic curve in respect of an axial deflection such that a progressively increasing spring force in the damping element occurs with increasing spring travel of the pump holder. The axial deflection of the pump holder is consequently reduced over that of the prior art. According to the invention, an elastic spring section (15) connects on the cantilever section (12) which runs with the longitudinal extension thereof in the axial direction and in the circumferential direction in respect of a pump axis (2.1) and is connected to the holder (11).