Elastically Deformable Cam Roller Carrier for Fuel Pump Misalignment

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Solution Overview

Problem

Misalignments between the cam lobe and cam roller in internal combustion engine fuel unit pumps lead to increased stress and manufacturing complexity, limiting fuel injection pressure and flow capabilities due to machining errors and tolerances.

Innovation Solution

An elastically deformable cam roller carrier aligns the cam roller with the cam lobe, allowing for compensation of initial misalignments and ensuring proper contact, thereby reducing stress on the cam roller and enabling higher fuel pressures without oversizing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cam roller is dimensioned larger to compensate for misalignments, then the contact area between cam lobe and cam roller increases, but the device complexity and manufacturing cost increase

Engineering Contradiction:

Improvecontact area between cam lobe and cam rollerVSAvoidcam roller size

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The cam roller carrier is made elastically deformable, allowing it to dynamically adjust its position and orientation in response to misalignments between the cam lobe and cam roller. This dynamic adaptation enables the system to maintain proper contact without requiring an oversized cam roller, thereby resolving the contradiction between reliability and device complexity

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The elastic deformability of the cam roller carrier allows it to change its physical parameters (position, orientation, shape) in response to misalignments. This parameter change enables the system to compensate for manufacturing tolerances and maintain optimal contact conditions without increasing the cam roller dimensions

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If machining tolerances are made stricter to avoid misalignments, then the alignment precision between cam lobe and cam roller improves, but the manufacturing cost increases

Engineering Contradiction:

Improvealignment between cam lobe and cam rollerVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The cam roller carrier performs self-alignment through its elastic deformability, automatically compensating for misalignments without requiring precision machining. This self-correcting mechanism allows the use of standard machining tolerances while achieving proper alignment, thereby resolving the contradiction between manufacturing precision and ease of manufacture

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention converts the harmful effect of misalignments (caused by machining tolerances) into a beneficial self-alignment process. The elastic deformability of the cam roller carrier allows it to absorb and correct misalignments, transforming what would be a manufacturing defect into a self-correcting feature that eliminates the need for strict machining tolerances

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Stability of the object's composition

If the cam roller carrier is made rigid to maintain precise alignment, then the alignment stability improves, but the ability to compensate misalignments decreases

Engineering Contradiction:

Improvealignment stabilityVSAvoidmisalignment compensation

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The cam roller carrier transitions from a rigid structure to a dynamically deformable one, allowing it to adapt its configuration in response to misalignments while maintaining stable contact. This dynamic behavior enables the system to achieve both alignment stability and misalignment compensation simultaneously

Inventive Principle:

Principle #15Dynamics

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

The solution effectively compensates for manufacturing tolerances, allowing for increased fuel injection pressure and flow while reducing manufacturing costs and complexity by ensuring proper alignment and distributing stress evenly across the cam roller.

Implementation Method 1

The cam roller carrier is elastically deformable for aligning the cam roller with the cam lobe of the rotatable shaft

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS10436185B2Fuel unit pump and internal combustion engine including a fuel unit pump

Publication Date: 2019.10.08 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A fuel unit pump for an internal combustion engine includes a fuel unit pump body, a pumping plunger and a roller tappet for contacting a cam lobe of a rotatable shaft of the internal combustion engine. The roller tappet includes a roller tappet body connected to the pumping plunger, and a cam roller rotatably mounted on a cam roller carrier and defining a cam roller rotation axis. The cam roller carrier is coupled to the roller tappet body and is elastically deformable for aligning the cam roller with the cam lobe.