Rack Bearing and Wedge Adjuster Plug for Steering Clearance Control
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Solution Overview
Problem
Rack and pinion steering systems experience undesirable noise, suboptimal steering feel, and increased complexity due to axial or radial clearance between system components, which affect the reliability of meshing between the pinion gear and the rack.
Innovation Solution
Incorporating a rack housing with a non-metallic rack bearing that includes a spring element and an adjuster plug, where the rack bearing is preloaded axially and radially to ensure engagement with the rack housing, and the adjuster plug further biases the bearing portions for improved fit and reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If axial or radial clearance exists between system components, then manufacturing and assembly are easier, but system noise increases and steering feel performance deteriorates
Solution Approach 1:
The rack bearing is preloaded axially and radially during assembly to eliminate clearance between components before operation. The adjuster plug is positioned to apply preliminary biasing force to the bearing portions, ensuring engagement with the rack housing bore is established in advance, preventing noise and improving steering feel without requiring complex post-assembly adjustments
2Manufacturing precision
If axial or radial clearance exists between system components, then component fit is more tolerant, but steering feel performance deteriorates
Solution Approach 1:
The rack bearing is preloaded with axial and radial forces that change the physical state of the bearing portions, eliminating clearance and ensuring consistent engagement with the rack housing bore. This parameter change (from clearanced to preloaded state) improves steering feel performance while maintaining manufacturing precision through the adjuster plug mechanism that compensates for tolerance stack-ups
3Object-affected harmful factors
If clearance is reduced through preloading, then system noise decreases and steering feel improves, but device complexity increases
Solution Approach 1:
The adjuster plug serves multiple functions: it positions the rack bearing, applies axial preload, provides radial preload through engagement with the rack housing, and compensates for tolerance variations. The rack bearing itself performs both axial and radial support functions while maintaining engagement with the pinion gear. This multi-functionality reduces the need for separate adjustment mechanisms and reduces overall system complexity
4Reliability
If preloaded engagement is applied to compensate for tolerance stack-ups, then meshing reliability improves, but manufacturing complexity increases
Solution Approach 1:
The rack bearing and adjuster plug assembly automatically compensates for tolerance stack-ups through elastic deformation and preload distribution. The bearing portions are biased towards engagement with the rack housing bore, creating self-adjusting contact pressures that maintain reliable meshing between the pinion gear and rack without requiring complex manufacturing tolerances or manual adjustment procedures
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 minimizes system noise, enhances steering feel performance, and improves the reliability of meshing between the pinion gear and the rack by providing a secure, preloaded engagement that compensates for tolerance stack-ups and maintains contact under varying conditions.
Implementation Method 1
The rack bearing includes a spring element that extends between the first bearing portion and the second bearing portion
Implementation Method 2
the adjuster plug engagement surface is disposed in a nonparallel and a non-perpendicular relationship with respect to the second adjuster plug end
Data Source
AI summary
A rack and pinion steering system includes a rack housing, a rack bearing, and an adjuster plug. The rack housing defines a rack housing bore extending along an axis. The rack bearing is disposed within the rack housing bore. The rack bearing has a first bearing portion that is biasingly connected to a second bearing portion. The first bearing portion and the second bearing portion extend along the axis between a first rack bearing end and a second rack bearing end. The adjuster plug is disposed within the rack housing bore. The adjuster plug extends along the axis between a first adjuster plug end that engages the second rack bearing and a second adjuster plug end.