Wiper Motor Resilient Interface Assembly for Shaft Stability
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Solution Overview
Problem
Conventional wiper systems with worm-driven reduction gear motors face issues with loading deflection, axial and cross-axial movement, and rust/corrosion due to the use of pal-nuts and metal wave springs, which fail to effectively regulate output shaft movement and are prone to single-axis regulation and linear spring rates.
Innovation Solution
A resilient interface assembly, comprising a torus-shaped elastomeric spring installed between the housing and motor arm of the worm-driven reduction gear motor, provides resistance to loading deflection and dampens axial and cross-axial movement, ensuring constant gear mesh and regulated worm versus gear compliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a worm-driven reduction gear motor with pal-nut and metal wave spring is used to drive wiper assemblies, then the motor can convert singular angular motion into two-way linear reciprocal motion, but the output shaft experiences loading deflection and axial and cross-axial movement that cannot be effectively regulated
Solution Approach 1:
The patent changes the spring rate parameter from linear (metal wave spring) to progressive (elastomeric material with varying stiffness). The elastomeric material exhibits non-linear elastic behavior where the spring rate increases with compression, providing better regulation of output shaft movement while maintaining motion conversion capability
Solution Approach 2:
The patent employs composite construction by combining elastomeric material with metal components (output shaft, housing, motor arm). The elastomeric material provides damping and compliance, while the metal components provide structural strength, creating a hybrid system that resolves the contradiction between motion conversion and shaft stability
2Manufacturing precision
If pal-nut and metal wave spring are used for regulating axial travel of the output shaft, then single-axis regulation is achieved, but the system cannot effectively dampen cross-axial movement and is prone to rust and corrosion
Solution Approach 1:
The patent replaces the metal wave spring mechanical system with an elastomeric material-based system. The elastomeric material provides both axial and cross-axial damping through its viscoelastic properties, eliminating the need for separate corrosion protection measures while improving overall regulation capability
Solution Approach 2:
The elastomeric interface assembly performs multiple functions simultaneously: it regulates axial travel, dampens cross-axial movement, provides corrosion resistance, and reduces noise. This multi-functionality resolves the limitation of single-axis regulation while eliminating corrosion susceptibility
3Device complexity
If metal wave spring with linear spring rate is used, then simple construction is achieved, but the system is subject to rust and corrosion and cannot provide progressive damping
Solution Approach 1:
The patent changes the spring rate characteristic from linear to progressive by using elastomeric material. The material's non-linear elastic behavior provides progressive damping where the stiffness increases with compression, improving reliability without significantly increasing construction complexity
4Ease of manufacture
If conventional worm-driven reduction gear motor is used, then cost-effective solution is achieved, but loading deflection and unregulated output shaft movement result in unpredictable wear and rougher operation
Solution Approach 1:
The elastomeric material acts as an intermediary element between the motor components and the load. It absorbs and dampens loading deflections and output shaft movements, providing predictable wear characteristics and smoother operation while maintaining cost-effectiveness through simple implementation
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 resilient interface assembly results in predictable wear characteristics, smoother operation, and a compact, durable, weather-resistant, and cost-effective wiper system with improved mechanical compliance and reduced noise and inertia.
Implementation Method 1
A resilient interface assembly, comprising a torus-shaped elastomeric spring installed between the housing and motor arm of the worm-driven reduction gear motor, provides resistance to loading deflection and dampens axial and cross-axial movement
Implementation Method 2
dampens axial and cross-axial movement of the output shaft
Data Source
AI summary
A wiper system includes at least one wiper assembly, a linkage assembly connected to the at least one wiper assembly, and at least one worm-driven reduction gear motor having a housing, an output shaft rotatably supported by the housing, and a motor arm connected to the output shaft and the linkage assembly to drive the at least one wiper assembly in repeated wiping motion across a surface to be wiped. The wiper system also includes a resilient interface assembly disposed between the housing and the motor arm to provide resistance to loading deflection and damp axial and cross-axial movement of the output shaft of the motor.