Steering Column Adjusting Drive With Nested Spindles for Longer Travel
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Solution Overview
Problem
Existing motor-adjustable steering column adjusting drives require high drive torque and large constructional space due to high frictional and inertial forces, limiting the usable adjustment path and leading to bulky and heavy designs, especially when attempting to stow the steering wheel for autonomous driving modes.
Innovation Solution
A motorized adjusting drive with an external threaded spindle that can be partially hollow, allowing it to be immersed within the drive unit for increased adjustment path and reduced drive power requirements, utilizing a coupling device for flexible operation between plunger spindle and rotary spindle modes, and incorporating stop elements for mechanical simplicity and low maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a telescopically nested arrangement of two spindle drives is used to achieve greater adjustment paths, then the adjustment path is extended, but the drive torque and constructional space requirements increase significantly
Solution Approach 1:
The patent applies nesting by placing the second threaded spindle inside the first threaded spindle, creating a compact telescopic arrangement. This allows both spindles to operate within a confined space while providing extended adjustment paths, resolving the contradiction between long adjustment paths and large constructional space requirements.
Solution Approach 2:
The adjusting drive is divided into two independent spindle drives that can operate separately or in combination. Each spindle drive handles specific portions of the adjustment path, allowing the system to achieve greater total adjustment without requiring both drives to operate simultaneously at full capacity, thereby reducing peak drive torque requirements.
2Length of moving object
If a telescopically nested arrangement of two spindle drives is used to achieve greater adjustment paths, then the adjustment path is extended, but the constructional space and weight increase
Solution Approach 1:
The second threaded spindle is nested inside the first threaded spindle, creating a compact telescopic structure. This nesting arrangement minimizes the overall constructional space and reduces the amount of material required compared to a side-by-side configuration, thereby reducing weight while maintaining extended adjustment capability.
3Device complexity
If the external threaded spindle is fixedly supported on the drive unit to provide structural stability, then the structure is simplified, but the usable free adjustment path is limited
Solution Approach 1:
The patent makes the support configuration of the external threaded spindle dynamic rather than fixed. The external threaded spindle can be supported at different positions along the drive unit depending on the required adjustment path, allowing the system to adapt between structural simplicity and extended adjustment range as needed.
Solution Approach 2:
The adjustment path is divided into segments handled by different spindle drives. The external threaded spindle can be positioned to provide its full length as usable adjustment path when needed, while the internal threaded spindle provides additional adjustment range, allowing both spindles to contribute to the total adjustment path without requiring simultaneous full-length operation.
4Device complexity
If both spindle drives are always rotatably driven simultaneously in a nested arrangement, then the adjustment mechanism is simplified, but the frictional and inertial forces increase
Solution Approach 1:
The patent enables selective operation of the two spindle drives rather than requiring simultaneous operation. The control system can activate only the necessary spindle drive depending on the current adjustment requirements, reducing frictional and inertial forces by keeping one spindle stationary when its adjustment is not needed.
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 a more compact, lightweight, and flexible adjusting drive with reduced drive torque requirements, enabling a larger usable adjustment path and improved installation options, while maintaining robustness and low maintenance needs.
Implementation Method 1
a threaded spindle screwed into a spindle nut. By means of the drive unit, the threaded spindle and the spindle nut may be driven in rotation relative to one another about the threaded spindle axis
Implementation Method 2
The external threaded spindle is configured as a hollow spindle with an internal thread into which an internal threaded spindle engages
Data Source
AI summary
An adjusting drive for a motor-adjustable steering column for a motor vehicle, includes a motorized drive unit and an external threaded spindle which has an external thread and a coaxial internal thread into which an internal threaded spindle engages. The external threaded spindle and the internal threaded spindle can be driven in rotation relative to one another about an axis by the drive unit. In order to provide an adjusting drive which requires a reduced drive torque and delivers an optimized free adjustment path, the external threaded spindle engages with its external thread in a drive nut, wherein the drive nut or the internal threaded spindle is able to be driven in rotation by the drive unit and is supported relative to the drive unit in the direction of the axis.