Motor Pulley Tooth Count for Resonance Mitigation

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Solution Overview

Problem

Conventional motor pulleys often experience resonance phenomena due to noise frequency alignment, leading to increased noise, vibrations, and reduced durability, as the number of teeth is selected based solely on the output of the steering system without considering resonance mitigation.

Innovation Solution

Selecting the number of teeth for the motor pulley such that the noise resonance frequency is shifted to a higher frequency region by making it relatively prime to the motor poles, motor slots, and their least common multiple, thereby minimizing resonance influence and reducing noise and vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the number of teeth of the motor pulley is selected based solely on the output of the steering system, then the steering system output requirement is met, but the motor pulley noise frequency may become an integer number of times as high as the motor noise frequency, causing resonance phenomenon

Engineering Contradiction:

Improvesteering system outputVSAvoiddurability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the parameter of the number of teeth of the motor pulley from a conventional selection based solely on steering system output to a specifically calculated value that satisfies a mathematical relationship (noise resonance frequency being an integer multiple of motor noise frequency). This parameter change resolves the contradiction by simultaneously meeting steering system output requirements while avoiding resonance frequencies that would compromise durability.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the number of teeth of the motor pulley is selected based solely on the output of the steering system, then the steering system output requirement is met, but noise and vibrations become severe due to resonance phenomenon

Engineering Contradiction:

Improvesteering system outputVSAvoidnoise and vibrations

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by selecting a specific number of teeth for the motor pulley that satisfies the frequency relationship condition. This changes the noise resonance frequency to be an integer number of times as high as the motor noise frequency, thereby shifting the operating frequency away from resonant conditions and significantly reducing noise and vibrations while maintaining steering system output performance.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the number of teeth of the motor pulley is selected based solely on the output of the steering system, then the steering system output requirement is met, but the possibility of generating a resonance phenomenon increases

Engineering Contradiction:

Improvesteering system outputVSAvoidresonance phenomenon

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the selection criterion for the number of teeth from a simple output-based selection to a frequency-based selection where the noise resonance frequency is specifically set to be an integer number of times as high as the motor noise frequency. This parameter change minimizes the influence of resonance phenomena by avoiding critical resonance frequencies while maintaining the required steering system output.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8766507B2Motor pulley

Publication Date: 2014.07.01 HL MANDO CORP

AI summary

A motor pulley minimizes an influence of a resonance phenomenon, thereby reducing noise and vibrations and preventing lowering of durability.