Integrated No-Back Spring for Steering Torque Consistency
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Solution Overview
Problem
Traditional torque adjustment devices in vehicle steering systems face issues with longevity, weight, simplicity of design, and consistency due to changes in friction surfaces and partial rotation of axial springs, especially under higher torque requirements.
Innovation Solution
A no-back spring apparatus with an integrally formed body having retaining fingers and spring elements, which axially retains the bearing assembly within a housing structure, providing improved torque adjustment by combining axial spring and no-back washer functionality in a lightweight and simplified design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional torque adjustment devices use a plastic bearing sleeve with an axial spring and no-back washer, then torque adjustment capability is improved, but the device complexity increases and longevity decreases due to friction surface changes and spring rotation
Solution Approach 1:
The patent combines the axial spring and no-back washer into a single integrated component called a no-back spring apparatus. This merging eliminates the need for separate axial spring and no-back washer parts, reducing assembly complexity while maintaining the torque adjustment capability through the unified structure's interaction with the bearing sleeve's friction surface
Solution Approach 2:
The no-back spring apparatus serves multiple functions simultaneously: it provides axial retention, maintains preload on the bearing assembly, and enables torque adjustment through its friction interface with the bearing sleeve. This multi-functionality reduces the overall device complexity by consolidating what would otherwise require multiple separate components
2Adaptability or versatility
If traditional torque adjustment devices use a plastic bearing sleeve with friction surfaces, then torque adjustment is achieved, but reliability decreases due to friction surface changes during prolonged usage
Solution Approach 1:
The patent utilizes the friction coefficient parameter between the no-back spring apparatus and the bearing sleeve to achieve torque adjustment. By controlling the friction interface characteristics, the system can adjust torque within a narrow range while maintaining reliable operation. The friction surface changes during prolonged usage are accommodated through the elastic properties of the spring element, which compensates for wear and maintains consistent torque characteristics
3Adaptability or versatility
If traditional torque adjustment devices allow axial spring rotation, then torque adjustment is achieved, but longevity decreases due to spring winding and geometry deflection
Solution Approach 1:
The no-back spring apparatus features an asymmetric design with a flat portion on one axial side and a curved portion on the opposite axial side. This asymmetry prevents the apparatus from rotating during operation, as the flat portion interfaces with a corresponding flat surface that restricts rotation. By preventing spring rotation, the design eliminates spring winding and geometry deflection, significantly improving longevity while maintaining torque adjustment capability through controlled friction at the interface
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 enhances the longevity and consistency of torque adjustment, improves weight and design simplicity, and effectively meets both minimum and maximum torque requirements by maintaining the axial spring's stationary position and utilizing a frictional surface for enhanced rotational stability.
Implementation Method 1
at least one spring element integrally formed with the body and extending axially from the body and in contact with a frictional surface of the bearing sleeve
Implementation Method 2
The axial spring is intended to remain stationary while the steering shaft rotates due to the difference of friction interfaces, i.e. dry steel-on-steel between the no-back washer and axial spring versus lubricated steel of the axial spring on the plastic bearing sleeve frictional surface
Data Source
AI summary
A no-back spring apparatus includes a body having an annular shape extending between an outer diameter and an inner diameter, the body comprising a first axial side and a second axial side, the second axial side including a flat portion extending from the inner diameter toward the outer diameter. The no-back spring apparatus also includes a plurality of retaining fingers circumferentially spaced from each other and integrally formed with the body and extending radially outwardly from the outer diameter. The no-back spring apparatus further includes a plurality of spring elements integrally formed with the body, each of the plurality of spring elements including a tab portion extending radially inwardly from the inner dimeter.