Steering Rack Wear Compensator Using Rotating Cam
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Solution Overview
Problem
Rack and pinion steering systems often experience rattles due to wear in components, which existing compensation mechanisms fail to adequately address, particularly when driving over rough roads.
Innovation Solution
A wear compensator comprising a rack follower, an adjuster plug, a wear cam, and a torsion spring, which rotates to compensate for wear by axially lengthening as components wear, maintaining engagement between the rack and pinion shaft gear, thereby reducing or eliminating rattles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rack follower with a compression spring is used to bias the rack against the pinion shaft gear, then the rack is maintained in engagement with the pinion shaft gear, but wear in the system still results in rattles in the steering system
Solution Approach 1:
The wear cam is made rotatable relative to the adjuster plug, transforming the static compression spring system into a dynamic one. As wear occurs, the wear cam rotates incrementally, allowing the cam surfaces to maintain contact while compensating for dimensional changes in the rack and pinion gear, thereby preventing rattles while maintaining reliable engagement.
Solution Approach 2:
The torsion spring changes the rotational parameter of the wear cam to compensate for wear. As the rack and pinion gear wear, the torsion spring allows the wear cam to rotate, adjusting the effective position of the rack follower to maintain proper engagement and eliminate rattles.
2Object-affected harmful factors
If a wear compensator with rotatable wear cam and torsion spring is used to eliminate rattles, then steering rack assembly wear is compensated, but the packaging space in the steering assembly increases
Solution Approach 1:
The wear cam is positioned within the existing steering gear housing structure, nested between the rack follower and the adjuster plug. The torsion spring is mounted within the adjuster plug body, utilizing the existing internal space. This nested arrangement allows the wear compensator to fit within the conventional packaging space without significant volume increase.
Solution Approach 2:
The wear cam rotation occurs in a dimensional space that does not significantly increase the external packaging volume. The compensatory motion is achieved through rotational adjustment within the existing axial space, effectively using angular displacement to compensate for linear wear without requiring additional packaging volume.
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 wear compensator effectively reduces or eliminates rattles in the steering system while maintaining a similar packaging size to conventional assemblies, providing reliable wear compensation.
Implementation Method 1
The torsion spring connects between the adjuster plug and the wear cam and rotationally biases the wear cam relative to the adjuster plug
Implementation Method 2
The rack follower may include a main body having shoes extending therefrom configured to engage and slide against the rack
Implementation Method 3
the wear cam includes a wear cam surface operatively engaging the plug cam surface
Data Source
AI summary
A wear compensator for use in a vehicle rack and pinion steering assembly and a method of biasing a rack against a pinion shaft gear in a rack and pinion steering assembly are disclosed. The wear compensator may include a rack follower, an adjuster plug, a wear cam and a torsion spring. The rack follower slides on the rack. The adjuster plug is retained by the steering gear housing and includes a plug cam surface. The wear cam includes a wear cam surface operatively engaging the plug cam surface, is mounted between the rack follower and the adjuster plug, and can rotate relative to the adjuster plug. The torsion spring connects between the adjuster plug and the wear cam in order to rotatably bias the wear cam relative to the adjuster plug.