Powered Telescoping Mirror Gear Mechanism Noise Reduction
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Solution Overview
Problem
Existing powered telescoping vehicle rearview mirrors require high manual override force due to slip clutch assemblies and emit distracting noises from their motor and gear configurations, which are unacceptable to vehicle operators.
Innovation Solution
The implementation of pinion drive gear assemblies with rolling clutches or locking clutch assemblies that allow for full power drive force while minimizing manual override slide force and reducing noise by using a simpler gear configuration with a turnstile gear and pinion gear system, eliminating the need for a worm gear and split trunnions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a slip clutch assembly is used as a back-up system in powered telescoping mirrors, then the electrical motor is protected from back-driving, but the manual override slide force becomes substantially increased
Solution Approach 1:
The patent removes the slip clutch assembly from the drive system and replaces it with a direct-drive mechanism where the motor shaft is directly coupled to the telescoping mechanism through a simple gear reduction. This extraction of the slip clutch eliminates the high friction and complex clutch disc arrangements that caused high manual override forces, while the motor protection function is achieved through the inherent mechanical characteristics of the simplified drive train.
Solution Approach 2:
The patent replaces the mechanical slip clutch system with a simplified gear reduction system that provides motor protection through mechanical advantage rather than through clutch slippage. The gear reduction system naturally limits reverse forces transmitted to the motor while maintaining low friction for manual operation.
2Power
If traditional motor and gear configurations are used in powered telescoping mirrors, then the power drive function is achieved, but loud distracting noises are generated
Solution Approach 1:
The patent removes the worm gear and split trunnion components from the traditional motor-gear configuration. By extracting these noisy elements, the system achieves power drive function through a simpler pinion gear and turnstile gear arrangement that operates quietly while maintaining the necessary torque and force for telescoping operation.
Solution Approach 2:
The patent changes the gear configuration parameters from a worm gear system to a pinion-turnstile gear system. This parameter change in the mechanical transmission system fundamentally alters the noise characteristics while preserving the power transmission capability, resulting in significantly reduced operational noise.
3Power
If a worm gear and split trunnions configuration is used, then the motor-gear power transmission is achieved, but the system complexity and noise increase
Solution Approach 1:
The patent extracts and eliminates the worm gear and split trunnion components from the power transmission system. The remaining pinion gear and turnstile gear provide sufficient power transmission for the telescoping mechanism while dramatically reducing the number of parts, assembly steps, and potential failure points associated with the traditional configuration.
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 solution reduces manual override slide force to acceptable levels and eliminates distracting noises, maintaining the close dimensional arm interfaces for optimal vibration performance and ergonomic operation.
Implementation Method 1
rolling clutches for selectively disengaging the motor from the arm assemblies
Implementation Method 2
an electric motor mounted to the rearview head
Implementation Method 3
a turnstile gear interlocked with the pinion gear
Data Source
AI summary
A power telescoping external vehicle rearview assembly comprising a drive gear assembly for telescopically moving a rearview head between a retracted and an extended position is disclosed. An embodiment of the rearview assembly comprises a bracket mountable to a vehicle, a rearview head telescopically mounted to the bracket via a plurality of arm assemblies, a rearview element mounted to the rearview head, an electric motor mounted to the rearview head, and a gear assembly connected between the motor and the plurality of arm assemblies. An embodiment of the gear assembly comprises pinion drive gear assemblies with rolling clutches for selectively disengaging the motor from the arm assemblies, a fixed clutch assembly for transferring power from the motor to the pinion drive gear assemblies, and a drive shaft connecting the fixed clutch assembly to the pinion drive gear assemblies.