Steering Column Spindle Locking for Defined Adjustment Modes
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Solution Overview
Problem
Existing motor-adjustable steering column adjusting drives face limitations in adjustment behavior, particularly regarding haptics and acoustics, due to undefined operating modes in multi-stage spindle mechanisms, leading to inconsistent feel and sound during adjustments, and restricted design freedom.
Innovation Solution
A blocking device is introduced that selectively locks the outer threaded spindle with the spindle nut or the inner threaded spindle for conjoint rotation, allowing defined activation of either the first or second spindle mechanism, ensuring consistent haptic and acoustic characteristics and independent transmission ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a multi-stage adjusting drive with telescopically nested spindle mechanisms is used to achieve greater adjustment travel, then the adjustment range is improved, but the adjustment behavior becomes undefined with inconsistent haptic and acoustic characteristics
Solution Approach 1:
The blocking device dynamically switches between two operating modes: in the first mode, it blocks the inner threaded spindle to activate the first spindle mechanism for coarse adjustment; in the second mode, it blocks the outer threaded spindle to activate the second spindle mechanism for fine adjustment. This dynamic switching ensures defined and consistent adjustment behavior across the entire adjustment range while maintaining the extended travel capability.
2Length of moving object
If a multi-stage adjusting drive with telescopically nested spindle mechanisms is used to achieve greater adjustment travel, then the adjustment range is improved, but the design freedom is restricted due to coupled transmission ratios
Solution Approach 1:
The adjusting drive is segmented into two independent spindle mechanisms with separate transmission ratios. The first spindle mechanism (inner threaded spindle and first spindle nut) and the second spindle mechanism (outer threaded spindle and second spindle nut) can be designed with different transmission characteristics. The blocking device selectively engages one mechanism at a time, allowing independent optimization of each mechanism's transmission ratio for coarse and fine adjustment respectively, thereby restoring design freedom.
3Device complexity
If a simple rotary or spindle drive is used, then the structure is simple, but the maximum adjustment travel is limited by the length of the threaded spindle
Solution Approach 1:
The adjusting drive employs a telescopically nested arrangement where the inner threaded spindle is received within the outer threaded spindle. This nested configuration allows two spindle mechanisms to be integrated in a compact space, extending the adjustment travel beyond what a single spindle could provide while maintaining relatively simple structural elements. The blocking device enables selective engagement of each nested spindle mechanism.
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
This solution improves adjustment behavior by eliminating undefined mixed operating modes, providing distinct and consistent haptic and acoustic feedback, and increases design freedom by allowing tailored adjustment speeds and precision in different ranges.
Implementation Method 1
the threaded spindle and the spindle nut can be driven in rotation relative to one another about their common axis, the threaded spindle axis or spindle axis, by the drive unit, whereby the threaded spindle and the spindle nut can be moved toward one another or away from one another in translational fashion in the direction of the threaded spindle axis
Implementation Method 2
a blocking device that is switchable between a first position and a second position is provided, wherein, in the first position, the outer threaded spindle is locked together with the spindle nut for conjoint rotation, and in the second position, the outer threaded spindle is locked together with the inner threaded spindle for conjoint rotation
Data Source
AI summary
An adjusting drive for a motor-adjustable steering column may include an outer threaded spindle that has an external thread that engages with a spindle nut and that has an internal thread that is engaged by an inner threaded spindle. The spindle nut, the outer threaded spindle, and the inner threaded spindle can be driven in rotation relative to one another about an axis by a motor-type drive unit. The adjusting drive may also include a blocking device that is switchable between a first position and a second position. In the first position the outer threaded spindle is locked together with the spindle nut for conjoint rotation. In the second position the outer threaded spindle is locked together with the inner threaded spindle for conjoint rotation.