Servo Steering Ball Nut with Elastic Bearing
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Solution Overview
Problem
Existing servo-assisted steering systems face challenges in simplifying component assembly and reducing complexity, particularly in accommodating axial and tilting movements with radial loads, which are not efficiently managed by conventional bearings designed primarily for radial forces.
Innovation Solution
A servo-assisted steering system utilizing a ball nut mounted in a bearing with elastic support via corrugated springs, where thrust washers prevent spring penetration into light metal alloy components, allowing for axial and radial support with a narrow encircling contact surface, enabling simple and cost-effective assembly and tilting movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional radial bearings are used to support the ball nut, then radial loads are managed, but axial loads and tilting movements are not efficiently managed
Solution Approach 1:
The patent combines multiple bearing functions into a single integrated bearing unit that simultaneously handles radial loads, axial loads, and tilting movements. The bearing design merges the capabilities of radial bearings with axial support features, eliminating the need for separate components for each load type.
Solution Approach 2:
The bearing is designed to dynamically adapt to varying load conditions and movement requirements. It allows controlled tilting movements and axial displacement while maintaining radial support, providing dynamic versatility rather than static rigid support for each direction.
2Reliability
If spherical bearings or spherical roller bearings are used to enable tilting motion and tolerance compensation, then acoustic characteristics improve and mechanical play reduces, but the bearing design becomes more complex and less suited for primarily axial loads
Solution Approach 1:
The bearing incorporates localized spherical or curved surface features only in the specific areas where tilting motion and tolerance compensation are needed, while maintaining a simple overall structure optimized for axial load support. This applies spherical geometry locally rather than requiring the entire bearing to be complex spherical design.
3Ease of manufacture
If the ball nut is rigidly mounted in the housing, then assembly is simple, but thermal expansion and mechanical play cannot be compensated
Solution Approach 1:
The mounting transitions from rigid fixed positioning to a controlled dynamic mounting that permits limited movement. The ball nut can tilt and expand axially within controlled limits, accommodating thermal expansion and mechanical play while maintaining operational stability through the bearing's elastic support.
4Reliability
If spring elements are used to enable axial movement, then tolerance compensation improves, but the bearing design becomes more complex
Solution Approach 1:
The spring elements are integrated directly into the bearing structure rather than being separate external components. The bearing design merges the spring mechanism with the bearing races and housing, creating a unified component that provides both support and elastic compliance without requiring additional separate spring assemblies.
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 enables easier assembly and reduced complexity by using tried-and-tested components, effectively managing dynamic loads through axial springing and limited tilting, thus reducing mechanical stress and play, while maintaining acoustic and thermal performance.
Implementation Method 1
the bearing is elastically supported with respect to the frame in the axial direction by means of spring elements
Implementation Method 2
thrust washers prevent spring penetration into light metal alloy components
Implementation Method 3
a servomotor which drives an axially displaceable component via a nut
Data Source
AI summary
The invention relates to a servo-assisted steering system, in particular for a motor vehicle, having a servo motor which drives an axially displaceable component via a nut (1) which is mounted in a frame (9, 10) in a rotatable manner in a bearing (4), wherein the nut (1) engages with a threaded spindle (2) formed on the component and is supported via the bearing (4) elastically with respect to the frame (9, 10) in the axial direction by means of spring elements (18, 20) and is supported on the frame (9, 10) in the radial direction along a narrow encircling contact surface (8, 30), wherein the spring elements (18, 20) are corrugated springs.