Compliant Cam Using Elastically Compressible Material

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Solution Overview

Problem

Existing cam and follower systems require flexible components or additional deflection mechanisms, leading to increased complexity, cost, and alignment issues due to rigid cams, and result in wear and frictional contact problems.

Innovation Solution

A compliant cam system utilizing a rotatable cam body with an elastically compressible material portion that deflects to create a biasing force when rotated, eliminating the need for separate springs or deflectable members by using the cam's material to engage with a follower.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid cam is used in the cam and follower system, then the cam structure is simple and strong, but the system requires additional deflection mechanisms (springs or biasing devices) to allow cam lobe displacement, increasing system complexity and cost

Engineering Contradiction:

Improvecam structure strengthVSAvoidsystem complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The cam material's elastic modulus is changed to create an elastically compressible cam that can deflect under load. This parameter change allows the cam to provide both structural strength and necessary deflection without requiring separate spring mechanisms, thereby reducing system complexity while maintaining strength

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses composite material construction where the cam is made from materials with specific elastic properties that allow controlled deflection. This composite approach enables the cam to integrate both the structural function and the deflection function that were previously separated into distinct components

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If a rigid cam is used, then manufacturing is simpler, but alignment and tolerancing issues increase because the cam cannot accommodate variations through deflection

Engineering Contradiction:

Improvecam manufacturing simplicityVSAvoidalignment and tolerancing precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

By changing the material parameters to create an elastically compressible cam, the system gains tolerance to alignment variations. The cam's elastic deflection capability allows it to accommodate manufacturing tolerances and alignment variations without requiring extremely tight tolerancing, thus maintaining ease of manufacture while improving precision

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If a rigid cam is used, then the cam structure is simpler, but frictional contact wear increases requiring subsequent adjustment of cam and follower positioning

Engineering Contradiction:

Improvecam structure complexityVSAvoidcomponent wear resistance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The elastic compressibility parameter of the cam material is optimized to provide a compliant contact surface that reduces frictional wear. This parameter change allows the cam to maintain simpler structure while improving reliability by reducing wear through elastic deformation at the contact interface

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The elastically compressible cam material provides beforehand cushioning at the contact interface, absorbing impact and reducing frictional wear before damage can occur. This preemptive cushioning effect reduces component wear and extends service life without requiring complex protective mechanisms

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 compliant cam system reduces system complexity and cost by generating a biasing force through material deflection, minimizing wear and alignment issues while maintaining secure engagement without additional components.

Implementation Method 1

At least a portion of the cam is an elastically compressible material

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS9091339B2Compliant cam of composite materials

Publication Date: 2015.07.28 HARRIS CORP

AI summary

A compliant cam system includes a cam having a cam body rotatable with respect to a cam rotational axis. The cam body has a cam body center spaced from the cam rotational axis. At least a portion of the cam is an elastically compressible material. A follower having at least one follower surface is in contact with the compressible material portion of the cam. A cam non-deflected condition is defined when an elastically compressible material portion outer surface is in contact with the cam follower surface prior to deflection of the elastically compressible material portion. The cam when thereafter rotated with respect to the cam rotational axis moves the cam body center toward the follower. The elastically compressible material portion deflects, defining a deflected condition, creating a biasing force acting toward the follower, and releasably frictionally engaging the elastically compressible material portion with the follower.