Cam Follower Roller Retaining Plug Assembly

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Solution Overview

Problem

Existing cam follower roller devices require complex assembly and retention methods, such as deformations and gluing, which complicate storage, transport, and installation in fuel injection pumps and valve rocker systems.

Innovation Solution

A cam follower roller device with a removable retaining plug that provides a radial interference fit with the tappet body, allowing for temporary axial retention of the insert and sub-assembly during storage and transport, eliminating the need for permanent fixing means like deformations or gluing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If deformations are formed on the tappet body to fix the insert, then the insert is retained during storage and transport, but the assembly process becomes more complex and time-consuming

Engineering Contradiction:
Improveretention of insertVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A removable retaining plug is introduced as an intermediary component between the tappet body and the insert. This plug serves as a temporary retention mechanism during storage and transport, but can be easily removed before installation, thus providing reliable retention without permanent complex fixing means.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The retention function is segmented into two distinct phases: temporary retention during storage/transport using the retaining plug, and permanent retention during operation using the deformation features. This segmentation allows each phase to have its own optimized retention mechanism without compromising the other.

Inventive Principle:
Principle #1Segmentation

2Reliability

If permanent fixing means such as deformations or gluing are used, then the insert is securely retained, but the device requires more complex manufacturing processes and longer assembly time

Engineering Contradiction:
Improveretention of insertVSAvoidassembly time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The retaining plug is pre-installed on the tappet body before the insert is mounted. This preliminary action ensures that the insert is securely retained during storage and transport without requiring complex permanent fixing means, thereby reducing assembly time when the device is actually installed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The retaining plug acts as a temporary, disposable component that serves its purpose during storage and transport but is removed before installation. This approach is more time-efficient and less complex than permanent fixing means, as it requires simple insertion and removal rather than deformation or gluing processes.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of operation

If the cam follower roller device is assembled as a preassembled unit, then storage and transport are simplified, but the retaining mechanism requires additional components

Engineering Contradiction:
Improvestorage and transportVSAvoidnumber of components
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The retaining plug serves multiple functions: it acts as a retention mechanism during storage and transport, provides alignment guidance during assembly, and can be easily removed before installation. This multi-functionality justifies the additional component by eliminating the need for more complex retention mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The retention function is extracted as a separate, removable component (the retaining plug) rather than being integrated into the tappet body structure. This extraction allows the plug to be easily removed before installation while providing simple retention during storage and transport.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Facilitates simplified assembly, storage, and handling as a preassembled unit, with the retaining plug being easily removable for installation, reducing design complexity and assembly time.

Implementation Method 1

A radial interference fit is provided between the retaining plug and the tappet body. The retaining plug comprises a mounting portion fitted on or into the tappet body.

Methodology Applied
Scientific EffectRadial interference fit: Friction

Data Source

PatentEP3173612B1Cam follower roller device with retaining plug
Publication Date: 2019.09.18 AB SKF SKF PATENT DEPARTMENT
  • EP3173612B1 patent drawingFigure 1~2
  • EP3173612B1 patent drawingFigure 3

AI summary

The cam follower roller device comprises a tappet body (12) extending along an axis, an insert (18) mounted in the tappet body, a pin (14) mounted at least on said insert and a roller (16) mounted on said pin, The device further comprises a removable retaining plug (20) carried by the tappet body (12) and adapted to retain the insert relative to said body. A radial interference fit is provided between the retaining plug (20) and the tappet body.