Drive Train Discontinuity Detection Using Dual Shaft Encoders

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Solution Overview

Problem

Existing systems for monitoring mechanical drive trains for discontinuities, such as broken drive shafts or gear failures, require separate hardware and software and are not integrated directly into the drive unit, making them inefficient and inflexible for detecting and responding to complex drive train issues.

Innovation Solution

The integration of two incremental shaft encoders at the ends of a mechanical drive train, connected to a logic unit, such as a variable frequency motor drive, which compares their speed data, accounting for encoder resolution and gear ratios, and triggers actions like motor shutdown and load braking if a speed deviation exceeds preset values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate hardware and software are used to monitor drive trains, then detection capability is provided, but system complexity and inefficiency increase

Engineering Contradiction:

Improvedrive train discontinuity detectionVSAvoidseparate hardware and software components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines separate monitoring hardware and software into an integrated system within the drive unit itself. The controller is embedded directly in the drive unit, merging previously separate components into a unified system that reduces complexity while maintaining detection capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The controller within the drive unit performs multiple functions: it controls motor operation and simultaneously monitors drive train discontinuities. This multi-functionality eliminates the need for separate dedicated monitoring hardware, reducing overall system complexity while maintaining reliable detection.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If separate monitoring systems are used, then detection function is provided, but flexibility and integration efficiency decrease

Engineering Contradiction:

Improvediscontinuity detection accuracyVSAvoidsystem integration flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

By integrating the controller directly into the drive unit, the system achieves both accurate discontinuity detection and high flexibility. The unified structure allows the system to adapt to different drive train configurations while maintaining reliable monitoring through the embedded controller.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS7841583B1System and method for detecting a discontinuity in a mechanical drive train

Publication Date: 2010.11.30 MAGNETEK INC

AI summary

Two incremental shaft encoders are mounted on the two extreme ends of a mechanical drive train. The encoders generate data which is representative of the rotational speed of the drive train component proximate to where the encoder is mounted. The data from the encoders is communicated to a logic unit associated with operation of the drive train, such as a variable frequency motor drive (VFD). Software in the logic unit monitors and compares the speed of both encoders. An encoder resolution setting and a gear ratio are entered into the software parameters. If a difference in speeds (as monitored and indicated by the encoders) is greater than a preset value for a period longer than a preset time period, the logic unit displays an error message and a programmed action (such as motor shutdown and load braking) is executed.