Drive Train Linkage With Zero-Deadband Coupling for Backlash

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Solution Overview

Problem

Drive trains that couple input and output shafts often introduce backlash, which increases over time due to wear, leading to motion and vibration even when the transmission is at rest, affecting accuracy and efficiency.

Innovation Solution

A drive train linkage system with a drive arm and a driven arm coupled by multiple coupling members, forming a substantially zero mechanical deadband coupling, where the coupling members are adjusted to maintain a consistent relative relationship between the input and output shafts, reducing backlash and vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional drive trains with gear trains, belts, chains, or sprockets are used to couple input and output shafts, then torque transfer is achieved, but backlash is introduced that increases over time due to wear, leading to motion and vibration even when the transmission is at rest

Engineering Contradiction:

Improvebacklash controlVSAvoidvibration and motion at rest

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The drive train linkage is segmented into multiple rigid linkages (first linkage and second linkage) connected through coupling members, replacing traditional gear trains and belt-pulley systems. This segmentation eliminates backlash by using rigid connections without meshing teeth or flexible belts, thereby preventing vibration and motion at rest while maintaining reliable torque transfer between input and output shafts.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent replaces traditional mechanical transmission elements (gears, belts, chains, sprockets) with a rigid linkage system consisting of coupled arms and coupling members. This substitution eliminates the inherent backlash of meshing gears and flexible drive elements, providing a backlash-free torque transfer mechanism that does not generate vibration or unintended motion when at rest.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If traditional coupling mechanisms are used, then torque transfer is achieved, but mechanical deadband and backlash increase over time due to wear

Engineering Contradiction:

Improvealignment precisionVSAvoidbacklash stability over time

Core Design Contradiction:

Manufacturing precisionVSDuration of action of moving object

Solution Approach 1:

Instead of using traditional mechanisms that require periodic adjustment to compensate for wear-induced backlash, the patent inverts the approach by using rigid linkages with coupling members that maintain precise alignment without wear. The system is designed to be inherently stable over time, eliminating the need for adjustment and preventing backlash accumulation throughout the operational lifespan of the drive train.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The coupling members are designed with adjustable characteristics, allowing the system to adapt to minor variations in alignment or wear while maintaining zero mechanical deadband. This dynamic capability ensures that the drive train linkage preserves manufacturing precision and alignment accuracy throughout its operational life, preventing backlash from increasing over time.

Inventive Principle:

Principle #15Dynamics

3Reliability

If multiple coupling members are used to form zero mechanical deadband coupling, then backlash and vibration are reduced, but device complexity increases

Engineering Contradiction:

Improvetorque transfer accuracyVSAvoidnumber of coupling members

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into the coupling members, which simultaneously provide torque transfer, maintain alignment, and eliminate backlash. By merging these functions into a unified rigid linkage system rather than using separate components for each function, the design achieves zero mechanical deadband and high torque transfer accuracy while minimizing the overall complexity of the drive train mechanism.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11536352B2Drive train linkage and method therefor

Publication Date: 2022.12.27 THE BOEING CO

AI summary

A drive train linkage includes a drive arm having a drive arm pivot axis, a driven arm having a driven arm pivot axis, at least one first coupling member extending between and being rotatably coupled to each of the drive arm and driven arm, and at least one second coupling member extending between and being rotatably coupled to each of the drive arm and driven arm so that the at least one second coupling member opposes the at least one first coupling member, where the at least one first coupling member and the at least one second coupling member are coupled to both the drive arm and the driven arm so to form a substantially zero mechanical deadband coupling between the drive arm and the driven arm.