Rack Bearing Preload Plug for Quiet Rack-and-Pinion Steering

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

A rack and pinion steering system incorporating a non-metallic rack bearing with a spring element and an adjuster plug, where the rack bearing is preloaded axially and radially to ensure engagement between the rack and gear, reducing noise and improving steering feel by maintaining contact and compensating for tolerance stack-ups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If axial or radial clearance is present between system components, then manufacturing and assembly are easier, but system noise increases and steering feel performance deteriorates

Engineering Contradiction:

Improveease of assemblyVSAvoidsystem noise

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The rack bearing is preloaded axially and radially before operation to eliminate clearance between components. The spring element is pre-compressed to apply continuous preload force, ensuring components remain in contact during operation, which prevents noise and maintains steering feel performance.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the physical state of the bearing assembly by introducing preload forces that alter the contact conditions between components. The spring element modifies the force parameters to maintain constant contact pressure, eliminating the harmful effects of clearance while preserving ease of assembly through the adjustable plug mechanism.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If axial or radial clearance is present between system components, then system complexity is reduced, but steering feel performance deteriorates

Engineering Contradiction:

Improvesystem complexityVSAvoidsteering feel performance

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The spring element acts as an intermediary component that transmits preload force from the adjustable plug to the rack bearing. This intermediary mechanism enables precise control of contact forces between the pinion gear and rack, maintaining steering feel performance while adding only one simple component to the system.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The spring element automatically maintains constant preload on the rack bearing throughout operation, self-adjusting to compensate for tolerance variations and wear. This self-regulating mechanism ensures consistent steering feel performance without requiring complex active control systems.

Inventive Principle:

Principle #25Self-service

3Device complexity

If axial or radial clearance is present between system components, then system complexity is reduced, but reliability of meshing deteriorates

Engineering Contradiction:

Improvesystem complexityVSAvoidreliability of meshing

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The rack bearing is preloaded axially and radially before operation to eliminate clearance between components. The spring element is pre-compressed to apply continuous preload force, ensuring components remain in contact during operation, which prevents noise and maintains steering feel performance.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The spring element acts as an intermediary component that transmits preload force from the adjustable plug to the rack bearing. This intermediary mechanism enables precise control of contact forces between the pinion gear and rack, maintaining steering feel performance while adding only one simple component to the system.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 maintaining a consistent preload and reducing rattle and clunk, thereby simplifying the system complexity.

Implementation Method 1

The rack bearing includes a spring element that extends between the first bearing portion and the second bearing portion

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS11738797B2Wedge adjuster plug

Publication Date: 2023.08.29 STEERING SOLUTIONS IP HOLDING CORP

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.