Motor-Adjustable Steering Column with Eccentric Spindle Drive
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Solution Overview
Problem
Existing motor-adjustable steering columns require a large installation space and expose the threaded spindle to the outside, making them inefficient for compact designs, especially in conventional steering systems with a mechanically continuous steering shaft.
Innovation Solution
A motor-adjustable steering column design where the threaded spindle is arranged at a radial distance from the longitudinal axis and housed within a spindle tunnel formed in the jacket tube, allowing for a compact and protected spindle drive that is suitable for both conventional and steer-by-wire systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the threaded spindle is arranged outside the outer casing, then the adjustment drive is easily accessible and simple to service, but the installation space required is large and the threaded spindle is exposed to external influences
Solution Approach 1:
The patent implements nesting by placing the threaded spindle inside the actuating unit's jacket tube, which is itself nested within the outer casing. The spindle tunnel provides a dedicated pathway within the jacket tube that allows the threaded spindle to be housed protected while maintaining functional accessibility through the opening in the jacket tube.
Solution Approach 2:
The patent transitions from a conventional external arrangement to an internal arrangement by creating a spindle tunnel within the jacket tube's wall structure. This utilizes the radial dimension of the jacket tube to accommodate the threaded spindle, effectively moving the component from external space into the structural dimension of the existing housing.
2Reliability
If the threaded spindle is arranged coaxially on the longitudinal axis, then the threaded spindle can be accommodated in a protected manner within the actuating unit, but this arrangement is only suitable for steer-by-wire systems without a mechanically continuous steering shaft
Solution Approach 1:
The patent segments the functional pathways by creating separate tunnels: one for the steering spindle (coaxial, for mechanical steering continuity) and another for the threaded spindle (eccentric, for adjustment drive function). This segmentation allows both functions to coexist without interference, enabling compatibility with both conventional and steer-by-wire systems.
Solution Approach 2:
The patent employs asymmetric arrangement by positioning the threaded spindle eccentrically relative to the longitudinal axis, while maintaining the steering spindle's coaxial position. This asymmetric configuration within the symmetric jacket tube structure allows the threaded spindle to be protected while preserving the steering shaft's mechanical continuity.
3Volume of stationary object
If the steering column is designed for compact dimensions, then space in the motor vehicle is optimized, but the installation and servicing of the adjustment drive becomes more difficult
Solution Approach 1:
The jacket tube serves multiple functions: it provides structural support for the actuating unit, contains the spindle tunnel for protected spindle accommodation, and maintains the opening for steering spindle passage. This multi-functionality achieves compactness without sacrificing serviceability, as the threaded spindle remains accessible through the existing opening.
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 design achieves a space-saving, compact, and dimensionally stable steering column with a protected spindle drive, enabling efficient adjustment and enhanced operational safety, including protection during crashes, while maintaining the ability to couple with steering gears.
Implementation Method 1
an electric servomotor and which engages in a spindle nut
Implementation Method 2
a threaded spindle which is arranged at least partially inside the actuating unit and which can be driven in rotation by an electric servomotor and which engages in a spindle nut, the threaded spindle being arranged at a distance from the longitudinal axis
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to a motor-adjustable steering column (1) for a motor vehicle, comprising an outer casing (3) which is supported by a support unit (4) that can be mounted on a vehicle body and in which outer casing an adjusting unit (2) is accommodated so as to be telescopically adjustable in the longitudinal direction, in which adjusting unit a steering shaft (22) is rotatably mounted in a casing tube (21) so as to be coaxially rotatably about a longitudinal axis (L), wherein an adjusting drive (5) is arranged between the outer casing (3) and the adjusting unit (2), said drive having a threaded spindle (56), at least part of which is arranged inside the adjusting unit (2) and which engages in a spindle nut (57) such that it can be rotationally driven by an electrical servomotor (54). In order to provide a compact adjusting drive (5) which is accommodated in a protected manner, according to the invention the threaded spindle (56) is arranged at a distance (a) from the longitudinal axis (L).