Pinion Shaft Swivel Ring for Low-Friction Steering Gear
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Solution Overview
Problem
Power-assisted steering systems in vehicles face issues with gear play-induced noise and high friction due to component tolerances and material wear, which affect steering feel and efficiency, especially during alternating steering and low-speed operations.
Innovation Solution
A steering gear design with a variable spring-loading rigidity for the pinion shaft, utilizing a swivel ring with torsion webs that deform to increase spring-loading under high torque, reducing friction and noise during low-torque conditions, and maintaining low friction for improved steering feel during normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the spring-loading rate is increased to eliminate gear play and reduce noise over the useful life, then noise development is reduced, but friction in the steering gear increases resulting in poor steering feel
Solution Approach 1:
The patent applies the dynamics principle by making the spring-loading rate variable rather than constant. The torsion webs in the swivel ring structure allow the spring-loading rate to change dynamically based on the swivel angle of the pinion shaft. During alternating steering operations, the spring-loading increases to eliminate gear play and reduce noise, while during normal steering operations, the spring-loading is reduced to maintain good steering feel with lower friction.
Solution Approach 2:
The patent implements parameter changes by varying the spring-loading rate as a function of the swivel angle. The torsion webs are designed with specific geometric parameters that cause the spring constant to change with the angle of rotation. This allows the system to optimize noise reduction at certain angular positions while maintaining acceptable friction levels during normal operation.
2Reliability
If the spring-loading rate is increased to ensure sufficiently high spring-loading throughout the useful life, then gear play is eliminated, but friction increases reducing steering efficiency
Solution Approach 1:
The dynamic characteristic of the torsion web structure allows the spring-loading rate to adapt to operational conditions. The swivel ring design enables the system to provide high spring-loading when needed (during alternating steering) while reducing energy loss during normal steering operations, thus improving overall steering efficiency without compromising reliability.
Solution Approach 2:
By changing the spring-loading parameter dynamically based on swivel angle, the system maintains reliable gear play elimination when required while minimizing energy loss during normal operation. The geometric design of the torsion webs ensures that the spring constant varies in a controlled manner to optimize both reliability and efficiency.
3Object-affected harmful factors
If a fixed high spring-loading is applied to the pinion shaft, then noise from gear play is reduced, but friction increases leading to poor steering feel especially in the new state
Solution Approach 1:
The patent employs dynamics by designing the swivel ring with torsion webs that create a variable spring-loading rate. This dynamic system automatically adjusts the spring-loading based on the operational state: high loading during alternating steering to eliminate noise, and lower loading during normal steering to maintain good steering feel, eliminating the need for compromise in fixed spring-loading designs.
Solution Approach 2:
The spring-loading parameter is changed dynamically as a function of the pinion shaft swivel angle. The torsion web geometry is specifically designed to provide high spring constant values when the shaft is in positions prone to gear play noise, while maintaining lower spring constant values during normal steering operations, thus resolving the contradiction between noise reduction and steering feel.
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 design effectively eliminates gear play noise and maintains a good steering feel over the vehicle's useful life by adjusting spring-loading based on torque levels, enhancing both noise reduction and steering efficiency.
Implementation Method 1
the torsion webs are twisted upon a rotation of the outer ring with respect to the bearing sleeve... the elastic restoring effect generated thereby produces the spring-loading of the pinion shaft
Implementation Method 2
The swivel ring comprises an inner ring and an outer ring connected to the inner ring via two torsion webs... the outer ring and the bearing sleeve are connected via a plurality of torsion webs which are twisted upon a rotation of the outer ring with respect to the bearing sleeve
Data Source
AI summary
A steering gear includes a gear wheel, a screw pinion meshing therewith, and a screw pinion shaft that includes the screw pinion. The screw pinion shaft is mounted on one side of the screw pinion in a fixed bearing. The steering gear includes a rotary bearing which comprises an inner bearing shell and an outer bearing shell. The outer bearing shell is connected to an inner ring of a swivel ring. The inner ring is connected to an outer ring of the swivel ring by a torsion web so as to pivot about a pivot axis. The torsion web runs at a distance from a supporting surface. The distance is dimensioned such that the torsion web does not contact the supporting surface when the screw pinion shaft is not loaded with a torque, and partially contacts the same when the screw pinion shaft is loaded with an operating torque.