Cam Follower Roller Device Angular Misalignment

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Solution Overview

Problem

Cam follower roller devices in automotive and industrial applications experience edge stresses due to angular misalignment between the tappet body and housing axes, leading to increased pressure contact with the cam, which can cause wear and inefficiency.

Innovation Solution

Incorporating deformable rings between the pin ends and the tappet body, providing a flexible connection that allows the pin to tilt and accommodate angular misalignment, thereby reducing edge stresses on the roller and minimizing pressure contact with the cam.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid connection is used between the pin and tappet body, then the structure is simple and strong, but edge stresses occur at the roller ends due to angular misalignment

Engineering Contradiction:
Improvestructural strengthVSAvoidedge stresses on roller
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent employs deformable rings as flexible elements positioned between the pin ends and the tappet body. These rings can deform elastically to accommodate angular misalignment between the tappet body axis and housing axis, preventing rigid stress concentration at the roller ends while maintaining structural integrity.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the rigidity parameter of the connection between pin and tappet body by introducing deformable rings. This allows the connection to transition from rigid to flexible, enabling angular adjustment to eliminate edge stresses on the roller while maintaining sufficient structural strength.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the pin is fixed rigidly to the tappet body, then manufacturing is simple, but angular misalignment increases pressure contact between roller and cam

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidpressure contact between roller and cam
Core Design Contradiction:
Ease of manufactureVSStress or pressure

Solution Approach 1:

The deformable rings serve as flexible intermediaries that allow angular adjustment of the pin relative to the tappet body. This flexibility accommodates misalignment without increasing manufacturing complexity significantly, as the rings can be installed in the existing hole structure.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The deformable rings act as intermediary elements between the pin and tappet body, providing a compliant connection that absorbs angular misalignment. This mediator allows the pin to tilt slightly, reducing pressure contact between the roller and cam while maintaining a relatively simple manufacturing process.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If deformable rings are introduced to allow pin tilting, then edge stresses are reduced, but device complexity increases

Engineering Contradiction:
Improveedge stresses on rollerVSAvoidstructural complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The deformable rings provide a relatively simple flexible connection solution. Each ring is a single component that can be pressed into place between the pin end and tappet body, adding minimal structural complexity while effectively reducing edge stresses through elastic deformation.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The introduction of deformable rings changes the mechanical parameter of the pin-tappet body connection from rigid to flexible. This parameter change enables angular adjustment to reduce edge stresses, while the simplicity of the ring geometry and installation process minimizes the increase in overall device complexity.

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

The flexible connection between the pin and tappet body reduces edge stresses and pressure contact, enhancing the operational efficiency and longevity of the cam follower roller device by accommodating misalignment and distributing forces more evenly.

Implementation Method 1

one deformable ring disposed between each pin end of said pin and an inner wall of the associated hole of said tappet body

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The edge stresses that may occur at the ends of the roller with the contact against the associated cam is reduced

Methodology Applied
Scientific EffectStress distribution: Deformation

Data Source

PatentEP3181836B1Cam follower roller device
Publication Date: 2020.02.05 AB SKF SKF PATENT DEPARTMENT
  • EP3181836B1 patent drawingFigure 1~2

AI summary

The cam follower roller device comprises a tappet body 12, a pin 14 and a roller 16 mounted on said pin, the tappet body comprising holes 12b, 12c for mounting pin ends 14b, 14c of said pin on said tappet body. The device further comprises one deformable ring 18, 20 disposed between each pin end 14b, 14c of said pin and an inner wall of the associated hole 12b, 12c of said tappet body.