Ceiling Fan Dual Redundant Motor Mounting Assembly
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Solution Overview
Problem
Existing ceiling fan designs lack redundancy in suspension systems, which can lead to failure and damage if the primary mounting structure fails, and they often experience vibration and wobble during operation, affecting efficiency and reliability.
Innovation Solution
A dual redundant motor mounting assembly with a downrod, hollow motor shaft, retaining pin, and retaining rod, along with a support cable and clevis system, provides a redundant suspension mechanism and reduces vibration through the use of a non-rotating motor shaft and downrod assembly, ensuring continued operation and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single motor mounting assembly is used, then the device complexity is reduced, but the reliability decreases due to lack of redundancy
Solution Approach 1:
The motor mounting assembly is segmented into multiple independent suspension paths: a primary suspension path including the downrod and motor shaft, and a secondary suspension path including the support cable and retainer assembly. This segmentation provides redundancy so that if one path fails, the other can maintain motor support, directly improving reliability without requiring a completely complex new system design.
Solution Approach 2:
The retainer plate and retainer assembly are positioned to engage with the motor shaft beforehand, creating a pre-positioned backup support mechanism. The support cable is pre-tensioned and ready to bear load if the primary downrod assembly fails. This beforehand cushioning ensures that when failure occurs, the redundant system is already in place to prevent catastrophic motor failure.
2Reliability
If a redundant suspension system is added, then the reliability improves, but the device complexity increases
Solution Approach 1:
The motor shaft serves multiple functions: it acts as both the primary structural support element for the motor and as a mechanical interface for the retainer assembly. The downrod assembly also provides dual functionality by serving as both a structural support and a conduit for electrical wiring to the motor. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity while maintaining redundancy.
Solution Approach 2:
The retainer plate is positioned within the motor housing structure, and the retainer assembly nests around the motor shaft. The support cable routes through existing structural elements of the ceiling fan assembly. This nesting approach allows the redundant suspension components to be integrated within the existing structure rather than adding external bulk, thus improving reliability while minimizing the increase in overall device complexity.
3Object-generated harmful factors
If the motor shaft is made non-rotating, then vibration is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The rotational function is extracted from the motor shaft and assigned to the motor housing instead. The motor shaft becomes a fixed non-rotating support element, while the motor housing rotates with the motor assembly. This separation allows the motor shaft to focus solely on providing precise structural support and alignment, reducing vibration and wobble, while the manufacturing precision requirements are concentrated on the housing-motor interface rather than the shaft itself.
Solution Approach 2:
The motor shaft extends beyond the minimum required length to provide additional engagement surfaces for the retainer plate and downrod assembly. This excessive action in terms of shaft length provides built-in alignment features and tolerance compensation, which actually reduces the precision requirements for other mating components while ensuring stable, vibration-free motor mounting.
Data Source
AI summary
A ceiling fan having a dual redundant motor mounting assembly for suspending a motor comprising a downrod, a hollow motor shaft suspending the motor from the downrod, a retaining pin extending through the hollow motor shaft, and a retaining rod coupled to the retainer pin for redundantly suspending the motor.