Plastic Coupling Assembly with Spring Segments for Axial Compliance
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Solution Overview
Problem
Existing coupling assemblies in vehicle steering systems face challenges in efficiently transferring torque while allowing axial stroke of the worm shaft, and maintaining alignment between the motor shaft and worm shaft, which affects the ease of assembly and functionality.
Innovation Solution
A coupling assembly formed from a lightweight plastic material with spline connections and clamp rings, combined with annularly shaped spring segments and connector ribs, enabling torque transfer and axial compliance to accommodate worm shaft stroke and misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a coupling assembly allows axial stroke of the worm shaft, then the worm shaft can accommodate axial movement, but torque transfer efficiency may be compromised
Solution Approach 1:
The coupling assembly is segmented into a motor shaft coupling, a worm shaft coupling, and a flexible coupling element. This segmentation allows the flexible coupling element to accommodate axial stroke while the splined connections maintain torque transfer efficiency through direct mechanical engagement.
Solution Approach 2:
The flexible coupling element acts as a flexible connector between the motor shaft coupling and worm shaft coupling. It provides axial compliance to accommodate worm shaft stroke while maintaining structural integrity for torque transfer through its splined geometry.
2Manufacturing precision
If the coupling assembly maintains alignment between motor shaft and worm shaft, then rotational accuracy is improved, but assembly complexity increases
Solution Approach 1:
The coupling assembly includes pre-formed splined bores and clamp ring mounting features that guide alignment during assembly. The clamp rings are pre-positioned to maintain alignment between the motor shaft and worm shaft, reducing the need for complex alignment procedures during installation.
Solution Approach 2:
The flexible coupling element serves as an intermediary between the motor shaft coupling and worm shaft coupling. It maintains alignment while accommodating minor misalignments and axial movements, simplifying the overall assembly process.
3Strength
If a coupling assembly uses clamp rings to secure shafts, then connection strength is improved, but ease of assembly deteriorates
Solution Approach 1:
The clamp rings are pre-positioned on the coupling assembly with alignment features that guide them onto the shafts. The splined bores and clamp ring geometry are designed to self-align during assembly, reducing the skill level and time required for installation while maintaining strong connections.
Solution Approach 2:
The coupling assembly is designed to be self-aligning during assembly. The splined connections and clamp ring features automatically position components correctly, allowing assembly without specialized tools or extensive training, while still providing strong secure connections.
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 ensures efficient torque transfer, allows for axial movement of the worm shaft, and enhances assembly ease by maintaining alignment and flexibility, reducing the risk of misalignment and improving the overall performance of the vehicle steering system.
Implementation Method 1
The coupling assembly includes a plurality of spring segments arranged along the worm shaft axis between the worm shaft and the motor shaft. The spring segments are connected to one another and to the worm shaft and motor shaft via connector ribs.
Data Source
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AI summary
Disclosed is a coupling assembly (10) including a first coupling end operably connectable to a first shaft (28) and a second coupling end operably connectable to a second shaft (22). A coupling body (30) of a plastic material is located between and operably connected to the first coupling end and to the second coupling end. The coupling body includes at least one spring segment (58) allowing relative motion between the first coupling end and the second coupling end along a coupling assembly axis. Also disclosed is a vehicle steering system utilizing the coupling assembly.