Torque Damper Motor Mitigates Gear Backlash and Resonance

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Solution Overview

Problem

Mechanical gear systems face issues with backlash and torsional resonance due to incompatible speed operations between prime movers and loads, leading to excessive wear, vibration, and resonance problems, which existing solutions like specialized gear design and tight tolerances fail to fully address, especially under dynamic loading conditions.

Innovation Solution

A controlled torque damper motor is introduced between the gearbox output and the load, powered by a power electronics-based variable speed drive, capable of rapid torque control to mitigate backlash and resonance, with configurations such as pulsed output and homopolar motor designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If specialized gear teeth design is used to address backlash, then gear engagement stability is improved, but manufacturing cost increases

Engineering Contradiction:

Improvegear engagement stabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

A damping motor is introduced as an intermediary device between the prime mover and the load. This motor actively compensates for backlash and torsional vibrations through controlled torque application, eliminating the need for specialized gear tooth designs while maintaining reliable gear engagement under dynamic loading conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If tight gear interface tolerances are used to reduce backlash, then gear mesh precision is improved, but mechanical friction increases

Engineering Contradiction:

Improvegear mesh precisionVSAvoidmechanical friction

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

Instead of using static tight tolerances to eliminate backlash, the invention employs a dynamic solution where a damping motor continuously adjusts torque to maintain proper gear engagement. This dynamic approach allows for standard tolerances while preventing the gear teeth from disengaging and reengaging, thereby reducing mechanical friction and wear.

Inventive Principle:

Principle #15Dynamics

3Object-affected harmful factors

If the system operates through critical speeds quickly to avoid resonance, then resonance damage is reduced, but mechanical stress on gears increases

Engineering Contradiction:

Improveresonance damageVSAvoidmechanical stress on gears

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The damping motor performs preliminary action by detecting and counteracting torsional vibrations before they amplify into resonant conditions. By continuously monitoring and compensating for torque fluctuations, the system can pass through critical speeds smoothly without experiencing excessive mechanical stress or resonance damage.

Inventive Principle:

Principle #10Preliminary action

4Reliability

If a fixed biasing torque is added to keep gear teeth engaged, then backlash is reduced, but system complexity increases

Engineering Contradiction:

Improvegear tooth engagementVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The damping motor provides self-service by automatically adjusting its torque output based on real-time system conditions. Rather than requiring a fixed biasing torque that must be manually set and maintained, the control system continuously monitors gear engagement status and dynamically adjusts the damping torque to maintain proper engagement without adding permanent mechanical complexity.

Inventive Principle:

Principle #25Self-service

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 torque damper motor significantly reduces backlash and resonance, providing improved output torque control and extending gear and bearing life by maintaining a constant gearbox output torque, even under varying load conditions, with the ability to dampen resonance and reduce wear.

Implementation Method 1

A torque damper motor 18, powered by a power electronics-based variable speed drive, is capable of rapid torque control to mitigate backlash and resonance

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The torque damper motor significantly reduces backlash and resonance, providing improved output torque control and extending gear and bearing life by maintaining a constant gearbox output torque

Methodology Applied

Scientific EffectElectromagnetic damping: Eddy Current Damping

Data Source

PatentUS8161843B2Damping motor and control approach for mitigating torsional backlash, damping critical geartrain speeds, and providing improved torque control in mechanical gears

Publication Date: 2012.04.24 FLORIDA STATE UNIV RES FOUND INC

AI summary

A torque damper motor connected to the output side of a mechanical gear system. The damper motor, along with its associated control system, mitigates backlash problems, reduced torsional resonance, and provides improved output torque control. In the preferred embodiment, the damper motor is powered by a power electronics-based variable speed drive. The damper motor can be significantly less powerful than the overall rating of the gear system (typically 5-10% of the overall rating) while still providing the enhanced performance.