Flexible Gear Compound Teeth Torque and Shock Trade-off

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Solution Overview

Problem

Existing clockwork mechanisms face challenges in achieving optimal torque transmission while maintaining resistance to shocks, particularly in flexible toothings made from micro-machinable materials like silicon, which struggle to balance efficiency and impact resistance.

Innovation Solution

A clock wheel design featuring compound teeth with a lug and an elastic blade, where the internal ends of the notches are positioned to allow minimal deformation under normal conditions and significant flexibility during impacts, ensuring effective torque transmission and impact resistance by maintaining the aspect ratio and curvature constraints of the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If flexible elastic parts are used in clockwork gears, then torque transmission efficiency is improved, but impact resistance deteriorates

Engineering Contradiction:
Improvetorque transmission efficiencyVSAvoidimpact resistance
Core Design Contradiction:
PowerVSStrength

Solution Approach 1:

The tooth is divided into two distinct segments: a rigid lug portion and a flexible blade portion. The rigid lug provides impact resistance while the flexible blade ensures torque transmission efficiency and backlash compensation, resolving the contradiction between these two opposing requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the tooth have different mechanical properties: the lug foot and lug body are made rigid for shock resistance, while the blade is made elastic for torque transmission. This local differentiation of material properties allows each part to fulfill its specific function optimally.

Inventive Principle:
Principle #3Local quality

2Strength

If rigid teeth are used for impact resistance, then shock resistance is improved, but torque transmission efficiency deteriorates

Engineering Contradiction:
Improveshock resistanceVSAvoidtorque transmission efficiency
Core Design Contradiction:
StrengthVSPower

Solution Approach 1:

The tooth is segmented into rigid lug for shock absorption and flexible blade for efficient torque transmission, allowing each segment to optimize its function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tooth combines rigid and elastic materials or material states in a single structure, creating a composite tooth that exhibits both rigid and flexible characteristics in different regions to satisfy conflicting performance requirements.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If micro-machinable materials like silicon are used, then manufacturing precision is improved, but impact resistance deteriorates

Engineering Contradiction:
Improvegear geometry precisionVSAvoidimpact resistance
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The tooth structure is segmented into rigid lug and flexible blade portions, allowing the rigid lug to provide impact resistance while the flexible blade maintains the benefits of micro-machining precision for torque transmission.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lug portion is designed with greater thickness and rigidity to withstand impacts, while the blade portion is optimized for precision manufacturing. This local quality differentiation allows the gear to achieve both manufacturing precision and impact resistance.

Inventive Principle:
Principle #3Local quality

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 design achieves zero backlash and improved shock resistance, maintaining performance under normal operation while allowing flexibility during impacts, ensuring the gear train can withstand significant stresses without compromising efficiency or durability.

Implementation Method 1

an elastic blade projecting from a blade foot facing said lug from which it is separated by a ventral notch

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2672336B1Flexible gear
Publication Date: 2018.08.15 OMEGA SA
  • EP2672336B1 patent drawingFigure 1
  • EP2672336B1 patent drawingFigure 2
  • EP2672336B1 patent drawingFigure 3~4

AI summary

The gear (10) has teeth (2) comprising a pin (3) projecting from a pin foot. An elastic blade (4) projects from a foot blade (41) facing toward the pin that is separated by a ventral notch. The elastic blade comprises a concave profile located opposite to the pin for delimiting a dorsal notch. The foot blade is delimited toward a rotation axis of the gear by inner ends of the ventral- and dorsal notches. The pin is bifurcated, and comprises two teeth (81, 85), which enclose a recess (87) and have greater rigidity than that of the elastic blade. An independent claim is also included for a clockwork wheel.