Steering Rack Force Sensing via Radial Compressive Measurement
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Solution Overview
Problem
Existing steering devices struggle to reliably and easily detect or measure the rack force acting on the rack, which is crucial for simulating realistic steering feel in steer-by-wire systems.
Innovation Solution
A steering device with a sensor mechanism that measures the compressive force component directed radially to the longitudinal axis of the rack, allowing for indirect determination of the rack force acting in the axial direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piezoelectric transducers are used to directly measure axial forces on the pinion, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces a pressing mechanism as an intermediary component that transfers the rack force to the sensor mechanism. Instead of directly measuring the axial force on the rack, the pressing mechanism converts this force into a compressive force that acts on the sensor mechanism, enabling indirect measurement while simplifying the overall system architecture
Solution Approach 2:
The patent replaces direct mechanical force measurement with an indirect measurement approach using a sensor mechanism that detects compressive forces. This substitution allows for simplified sensor integration while maintaining measurement capability through the mechanical advantage provided by the pressing mechanism
2Reliability
If direct measurement of axial rack force is implemented, then measurement reliability is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent inverts the measurement approach by not directly measuring the axial rack force, but rather measuring the compressive force generated by the pressing mechanism. This inversion simplifies the manufacturing process as the sensor mechanism can be integrated into the existing pressing mechanism structure, avoiding complex direct measurement installations
3Ease of manufacture
If a sensor mechanism measuring compressive force is used, then ease of manufacture is improved, but measurement precision deteriorates
Solution Approach 1:
The patent changes the measurement parameter from direct axial force to compressive force generated by the pressing mechanism. This parameter change allows the use of simpler compressive force sensors while maintaining measurement accuracy through the mechanical relationship between the rack force and the compressive force in the pressing 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
Enables reliable and easy detection of rack force, facilitating the simulation of steering forces and enhancing the steering feel in steer-by-wire systems.
Implementation Method 1
the sensor mechanism is designed in such a manner and/or arranged so that a compressive force component directed radially to the longitudinal axis of the rack can be detected or measured by the sensor mechanism
Data Source
AI summary
A steering device for a vehicle, having a rack which is mounted so as to be displaceable in a direction of a longitudinal axis of the rack, having a pinion, wherein the rack meshes with the pinion, having a pressing mechanism, wherein the rack is pressed against the pinion by the pressing mechanism, and having a sensor mechanism. The sensor mechanism is designed at least for measuring a compressive force. To detect or measure a rack force of the rack reliably and/or easily, the steering device is characterized in that a compressive force component directed radially to the longitudinal axis of the rack can be detected or measured by the sensor mechanism.