Steering Lock Detent Star Wheel Torque Control
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Solution Overview
Problem
Existing steering lock systems for motor vehicles face challenges in achieving a reproducibly defined torque limit between the steering shaft and locking element, with existing solutions requiring significant effort, being costly, or prone to manufacturing defects such as cracking.
Innovation Solution
A locking star with a hollow profile and evenly distributed U-shaped projections on its outer circumference, forming locking recesses that occupy between two-fifths and three-quarters of the circumference, providing a defined and elastic contact surface for secure attachment to the steering spindle without damage, and a method involving bending, rolling, or extrusion for production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a locking star with projections is pushed onto the steering column under force, then the locking star can be securely attached to the steering spindle, but the shape of the locking star is not elastic enough to allow the detent element to be pushed onto the steering column under force while adequately absorbing manufacturing tolerances
Solution Approach 1:
The locking star is designed with a thin-walled hollow profile structure that provides flexibility and elasticity. The thin walls allow the structure to deform elastically under mounting forces and accommodate manufacturing tolerances, while still maintaining sufficient strength for secure attachment to the steering spindle.
2Ease of manufacture
If the locking star is formed by deep drawing or bending processes, then the locking recesses can be created, but cracking can occur at high degrees of deformation, especially in the bending radii
Solution Approach 1:
The locking star features rounded corners and curved transitions in its profile design. These curved geometries reduce stress concentration during forming operations, preventing cracking in the bending radii while maintaining the structural integrity needed for reliable operation.
Solution Approach 2:
The wall thickness of the hollow profile is optimized to balance flexibility and strength. By carefully controlling the wall thickness parameter, the locking star can withstand the deformation required for mounting without cracking, while still providing sufficient structural strength for secure attachment.
3Reliability
If tolerance rings are used to connect the steering lock to the steering column shaft, then the steering lock can be secured, but considerable effort is required to achieve a defined torque limit between the shaft and the detent element, necessitating two tolerance rings or machining of grooves into the shaft
Solution Approach 1:
The locking star integrates multiple functions into a single component: it provides the locking mechanism through its locking recesses, establishes the torque limit through its friction fit on the steering spindle, and eliminates the need for separate tolerance rings or machined grooves. This consolidation simplifies the overall device structure while maintaining reliable torque limiting functionality.
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 locking star achieves a reproducibly defined torque limit, is easy and inexpensive to manufacture, and ensures secure attachment to the steering spindle, preventing damage from excessive torque while allowing for smooth operation and theft prevention.
Implementation Method 1
a defined and elastic contact surface for secure attachment to the steering spindle without damage, and a method involving bending, rolling, or extrusion for production
Data Source
Figure 1~5
Figure 6~11
Figure 12~13
AI summary
The invention relates to a detent star wheel (2) for a steering lock of a motor vehicle, comprising a hollow profile having a longitudinal axis (11) and a plurality of detent recesses (3), which can be brought into engagement with a locking bolt (5) of the steering lock that can be moved to a locking or unlocking position (5). The detent recesses (3) are formed by projections (9, 9'), and an inner surface (7) of the detent star wheel (2) forms a contact surface (8) that in the circumferential contour is circularly perforated, wherein the detent recesses (3) extend consistently in parallel to the longitudinal axis (11) across the entire length (l) of the detent star wheel (2).