Steering Rack Axial Pressure via Segmented Elastic Elements
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Solution Overview
Problem
Existing rack-and-pinion steering systems face challenges in maintaining constant axial pressure and compensating for wear without complex assembly or generating disturbing rattle noise, especially due to the difficulty in achieving precise axial adjustment under significant axial preload.
Innovation Solution
An apparatus with a support yoke and two elastic elements, where a first elastic element generates axial load and a second elastic element, independent of the axial load, provides a parallel force flow to adjust the abutment member, allowing for easier and more precise adjustment, and a resilient spacer ensures clearance for dimensional variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single elastic element is used to provide axial load on the support yoke, then the axial pressure force can be maintained, but the adjustment of the abutment member becomes difficult and imprecise due to the considerable axial preload
Solution Approach 1:
The single elastic element is segmented into two separate elastic elements: a first elastic element (axial spring) that provides the axial load, and a second elastic element (torsion spring) that provides the circumferential adjustment force. This segmentation allows the adjustment function to be independent from the axial loading function, enabling precise and easy adjustment of the abutment member without being hindered by the axial preload.
2Ease of operation
If a torsional spring is used to generate screwing movement of the adjustment member, then adjustment is possible, but the assembly becomes complex and expensive
Solution Approach 1:
The abutment member is designed with a screw thread that serves dual functions: it converts the circumferential force from the second elastic element into axial displacement for wear compensation, and it also serves as the adjustment mechanism itself. This multi-functionality eliminates the need for separate adjustment mechanisms and reduces overall assembly complexity.
3Force
If the axial load acts upon both the support yoke and the abutment member, then the axial pressure is maintained, but the abutment member cannot be adjusted easily due to the preload
Solution Approach 1:
The load path is segmented into two separate force flows: the first elastic element provides axial load exclusively to the support yoke and bearing element, while the second elastic element provides circumferential force exclusively to the abutment member for adjustment. This segmentation ensures that the axial pressure force is maintained while the abutment member can be adjusted easily and precisely without being subjected to the full axial preload.
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 apparatus achieves a simple and precise axial pressure force with automatic wear compensation, reducing the risk of rattle noise and maintaining desired clearance, even under varying conditions, through a combination of axial and circumferential elastic elements.
Implementation Method 1
a first elastic element (24) providing an axial load (FA) acting upon the support yoke (20) and the bearing element (22) to urge the support yoke (20) against the rack (12)
Implementation Method 2
a separate, second elastic element (28) providing a load (FC) acting upon the abutment member (26) in a circumferential direction (30) to urge the abutment member (26) against the support yoke (20)
Implementation Method 3
a wear-compensating abutment member (26) coacting with the bearing element (22) such that a relative rotation about the axis (A) generates an axial displacement of the abutment member (26) relative to the bearing element (22)
Data Source
Figure 1
Figure 2~4
Figure 5~7
AI summary
An apparatus (10) for pressing a rack (12) against a pinion (14) of a steering gear assembly (16) includes a housing (18), a support yoke (20) slidably guided in the housing (18) along an axis (A), a bearing element (22) that is fixed to the housing (18) in an axial direction, a first elastic element (24) providing an axial load (FA) acting upon the support yoke (20) and the bearing element (22) to urge the support yoke (20) against the rack (12), a wear-compensating abutment member (26) coacting with the bearing element (22) such that a relative rotation about the axis (A) generates an axial displacement of the abutment member (26) relative to the bearing element (22), and a separate, second elastic element (28) providing a load (Fc) acting upon the abutment member (26) in a circumferential direction (30) to urge the abutment member (26) against the support yoke (20).