Steering Column Safety Element Reducing Breakaway Torque
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Solution Overview
Problem
Conventional steering columns with additional intermediate bearings for radial support increase breakaway torque and manufacturing complexity, leading to safety risks and high forces required for telescopic adjustment, especially during crashes.
Innovation Solution
A steering column design featuring a safety element, such as an annular element or retaining ring, that creates a radial safety distance between the casing unit and steering spindle, restricting deflection and preventing excessive force during crashes without forming a mechanical connection during normal operation, thus reducing bearing friction and manufacturing tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an additional intermediate bearing is added to provide radial support for the steering spindle, then the rigidity of the steering spindle is improved and vibration transmission is reduced, but the breakaway torque is increased due to bearing friction
Solution Approach 1:
The patent removes the additional intermediate bearing from the steering column assembly, extracting the source of excessive friction while retaining the essential radial support function through the front and rear bearings alone. This eliminates the unnecessary bearing friction that increases breakaway torque.
Solution Approach 2:
Instead of adding more bearings to increase rigidity, the patent inverts the approach by reducing the number of bearings to three (front, rear, and optionally one intermediate), thereby reducing friction and breakaway torque while maintaining sufficient rigidity through optimized bearing placement and steering spindle design.
2Stability of the object's composition
If an additional intermediate bearing is added for radial support, then the steering spindle stability is improved, but the manufacturing complexity and tolerance requirements are increased
Solution Approach 1:
The patent extracts the unnecessary intermediate bearing component, thereby simplifying the manufacturing process and reducing tolerance requirements. The front and rear bearings provide sufficient radial support without the complexity of an overdetermined three-bearing arrangement.
Solution Approach 2:
The patent segments the bearing arrangement into essential front and rear bearings only, eliminating the redundant intermediate bearing. This segmentation reduces the number of components and assembly steps, thereby reducing manufacturing complexity.
3Stability of the object's composition
If an additional intermediate bearing is added for radial support, then vibration transmission to the steering wheel is reduced, but the forces required for telescopic adjustment are increased
Solution Approach 1:
The patent removes the additional intermediate bearing that causes excessive friction, thereby reducing the forces required for telescopic adjustment of the steering column while maintaining sufficient vibration reduction through the front and rear bearings.
4Stability of the object's composition
If the steering spindle is overdetermined with three bearings, then radial support is improved, but the steering column can lock during crashes due to increased friction
Solution Approach 1:
The patent extracts the redundant intermediate bearing from the overdetermined three-bearing arrangement, reducing bearing friction to levels that prevent locking during crashes while maintaining sufficient radial support through the front and rear bearings for reliable steering operation.
Solution Approach 2:
The patent changes the parameter of bearing quantity from three to two essential bearings, thereby altering the friction characteristics to ensure the steering column remains operable during crashes without locking due to excessive bearing friction.
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 effectively restricts steering spindle deflection to a safe threshold, ensuring the steering column can be safely pushed together during crashes without excessive force, reducing manufacturing complexity and preventing lock bolt jumping, while maintaining normal operation functionality.
Implementation Method 1
a safety element is arranged between the steering gear-side end of the casing unit and the rear bearing... which safety element leaves a circumferential radial safety distance between casing unit and steering spindle
Implementation Method 2
the impact energy in the crash can be reduced in a controlled manner by energy-absorption apparatuses arranged between the telescopic casing tubes or between the casing unit and a support unit of the steering column
Implementation Method 3
the hollow shaft of the steering spindle is mounted on one side in a front anti-friction bearing... and on the other side the steering shaft which is telescopic in the hollow shaft is mounted in a rear anti-friction bearing
Data Source
AI summary
A steering column for a motor vehicle includes a case with a steering gear-side end and a steering wheel-side end. The case includes an outer casing tube in which an inner casing tube is arranged telescopically and in which a steering spindle is mounted rotatably about a longitudinal axis. The steering spindle includes a hollow shaft in which a steering shaft is arranged telescopically. The steering spindle is mounted rotatably in a rear bearing in the steering wheel-side end portion. A safety element may be arranged between the steering gear-side end of the case and the rear bearing between the case and the steering spindle, which leaves a circumferential radial safety distance between the case and steering spindle which is smaller than the radial distance between the case and steering spindle outside the safety element between the steering gear-side end of the case and the rear bearing.