Steering Pinion Worm Drive Packaging
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Solution Overview
Problem
Electromechanical motor vehicle steering systems with electric drive devices directly on the steering pinion face challenges in packaging and crash behavior due to limited torque transmission and space constraints, especially when a torque sensor is present.
Innovation Solution
The electric drive device engages with the steering pinion via a worm wheel, with the steering rack positioned between the worm wheel and the steering column, allowing for a more compact and flexible arrangement, including a worm shaft with a single-stage transmission and the worm wheel mounted on the steering pinion, which can be fastened independently with positive or non-positive connections for overload protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electric drive device is placed directly on the steering pinion, then higher steering performance is achieved, but package options are limited due to space constraints and torque sensor arrangement
Solution Approach 1:
The patent repositions the electric drive device from a lateral arrangement to a longitudinal arrangement along the steering column. The drive device is positioned above the steering pinion assembly, utilizing the vertical space along the steering column rather than lateral space, thereby resolving the packaging conflict while maintaining direct engagement with the pinion for high steering performance.
Solution Approach 2:
The electric motor is integrated into the steering column structure, with the drive device nested within the steering column housing. The motor shaft directly engages the steering pinion, creating a compact nested arrangement that eliminates the need for separate mounting space while maintaining direct drive capability.
2Area of stationary object
If the electric drive device is placed in the upper portion of the steering column, then packaging is improved, but maximum drive torques are limited due to transmission via the steering column and crash behavior challenges arise
Solution Approach 1:
The patent extracts the electric drive device from the traditional column-mounted position and relocates it to engage directly with the steering pinion. This extraction from the column's upper portion eliminates the torque transmission limitation through the column while the direct pinion engagement provides maximum torque transfer. The drive device is repositioned to work in conjunction with rather than through the column structure.
3Adaptability or versatility
If a second pinion is added to the steering rack, then the electric drive device can be attached, but device complexity increases due to two gear sections
Solution Approach 1:
The patent makes the single steering pinion multi-functional by having it serve both as the steering input element (engaged by the steering wheel via the column) and as the drive output element (engaged by the electric motor). The pinion's teeth are engaged by both the steering rack and the worm gear from the electric drive device, eliminating the need for a separate second pinion while maintaining all necessary functions.
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 configuration enhances packaging options, reduces installation conflicts with torque sensors, and provides a compact design while maintaining high steering performance by allowing the electric motor and worm wheel to be positioned below the steering rack, thus improving the overall efficiency and flexibility of the steering system.
Implementation Method 1
an electric drive device with an electric motor and a worm wheel arranged on the steering pinion
Data Source
AI summary
An electromechanical motor vehicle steering system includes a steering column, a steering rack, a steering pinion that couples the steering column to the steering rack, and an electric drive device with an electric motor and a worm wheel arranged on the steering pinion. The steering rack is arranged between the worm wheel of the electric drive device and the steering column.