Steering Column Height Adjustment With Spindle Spring Compensation
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Solution Overview
Problem
Existing steering column height adjustment devices experience uneven adjustment speeds and noise due to weight force counterforces, leading to annoying driver experiences, and prior solutions using helical springs consume significant installation space.
Innovation Solution
An electrically adjustable steering column with a threaded spindle driven by an electric motor and reduction gear, surrounded by a compression spring that counteracts weight force, optimizing space usage and reducing spring weight, with the spring force dimensioned to prevent one-sided loads and compensate weight force vectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a helical spring is arranged on a box-type rocker arm to support weight force, then the load on the height adjustment device is minimized, but the installation space is significantly increased
Solution Approach 1:
The spring arrangement is moved from the box-type rocker arm to the threaded spindle, changing the spatial dimension and location of the spring. This allows the spring to surround the spindle circumferentially, utilizing the vertical adjustment space more efficiently and reducing the overall installation footprint while maintaining the weight force compensation function.
Solution Approach 2:
The spring is arranged to surround the threaded spindle, with the spring enclosing the spindle in a nested configuration. This allows the spring to be integrated within the existing vertical space of the height adjustment mechanism, eliminating the need for additional external space that would be required if the spring were mounted on the rocker arm.
2Device complexity
If weight force is not compensated, then the structure is simpler, but the adjustment speed becomes uneven and noise increases
Solution Approach 1:
A compression spring is introduced to compensate for the weight force of the steering assembly. The spring is arranged to surround the threaded spindle and acts on the spindle nut, providing an upward force that counteracts the downward weight force. This ensures uniform adjustment speed in both raising and lowering directions while reducing noise, all within a compact space-efficient design.
3Speed
If spring force is increased to fully compensate weight force, then uniform adjustment speed is achieved, but one-sided load on spindle nut occurs
Solution Approach 1:
The spring force is deliberately designed to be less than the full weight force, providing partial compensation rather than complete counteraction. The spring constant is selected so that the spring force ranges from approximately 20-50N in the upper position to 80-120N in the lower position, while the weight force is approximately 100-150N. This partial compensation achieves sufficiently uniform adjustment speed while preventing permanent one-sided loading of the spindle nut.
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 provides nearly uniform adjustment speed and reduced noise, saving costs and installation space while ensuring pleasant sound patterns and efficient operation.
Implementation Method 1
The at least one spring exerts a spring force on the spindle nut which counteracts a weight force acting in the direction of the axis of rotation of the threaded spindle
Implementation Method 2
A rotational movement of the threaded spindle is converted into a translational movement of the spindle nut in a direction of the longitudinal axis of the threaded spindle
Data Source
AI summary
A height adjustment device of a steering column of a motor vehicle includes an electric motor and a reduction gear. The electric motor drives a threaded spindle to raise and lower a steering assembly connected to the steering column. The threaded spindle is engaged with a spindle nut, a rotational movement of the threaded spindle is converted into a translational movement of the spindle nut in a direction of a longitudinal axis of the threaded spindle, and the threaded spindle is surrounded on a circumferential side by at least one spring that exerts a spring force on the spindle nut to counteract a weight force of the steering assembly acting in the direction of the axis of rotation of the threaded spindle. The at least one spring includes a compression spring between the reduction gear and the spindle nut and tensioned when the steering assembly is lowered.