Hollow Motor Steering Column Adaptive Gear Ratio
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Solution Overview
Problem
The existing Active Front Steering (AFS) systems are costly due to their complexity and high number of components, limiting their widespread application in vehicles beyond premium models, necessitating a simpler and more cost-effective solution.
Innovation Solution
A lower-end adaptive front steering system is developed using a hollow motor integrated with a steering column shaft and planetary gear trains, reducing the number of components and allowing for a compact design by changing the steering gear ratio based on the motor's rotation direction and amount, with a locking unit for system failure scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional AFS system with separate actuator and decelerator is used, then steering adaptability is improved, but device complexity and material cost increase
Solution Approach 1:
The patent combines the actuator (motor) and decelerator (planetary gear train) into a single integrated hollow motor assembly. The motor is positioned inside the steering column shaft, and the planetary gear train is integrated with the motor housing, eliminating the need for separate actuator and decelerator components found in conventional AFS systems.
Solution Approach 2:
The motor is nested inside the steering column shaft in a coaxial arrangement. The planetary gear train is nested within the motor housing structure, with planet gears positioned between the sun gear (connected to motor shaft) and ring gear (connected to lower shaft). This nested configuration reduces component count and simplifies the overall system architecture.
2Adaptability or versatility
If a conventional AFS system with multiple components is used, then steering adaptability is improved, but material cost increases
Solution Approach 1:
The patent merges multiple components into fewer integrated parts. The motor housing serves dual functions as both the actuator housing and the decelerator housing. The planetary gear train shares common components (housing, shafts) with the motor assembly, reducing the total quantity of materials required compared to conventional systems with separate actuators and decelerators.
Solution Approach 2:
The motor housing is designed to perform multiple functions: it houses the motor, serves as the decelerator housing, and provides mounting structures for the planetary gear train. This multi-functionality reduces the need for additional separate components and materials.
3Adaptability or versatility
If the motor housing rotates with the upper shaft, then steering gear ratio adjustment is achieved, but wire twisting may occur
Solution Approach 1:
The system dynamically adjusts the steering gear ratio by controlling the motor's rotation direction and amount. The ECU commands the motor to rotate in specific directions and by specific amounts based on driving conditions, enabling real-time adaptation of the steering ratio without mechanical linkages that would cause wire twisting.
Solution Approach 2:
The ECU receives feedback from sensors (steering torque sensor, vehicle speed sensor) and adjusts the motor control signals accordingly. This closed-loop control enables precise adjustment of the steering gear ratio while monitoring system state to prevent harmful effects such as wire twisting.
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 solution simplifies the system, reduces material costs, and ensures steering convenience and stability by minimizing component count and eliminating twisted wires, while maintaining optimal steering performance and packaging efficiency.
Implementation Method 1
an upper planetary gear train (15) which transmits power between the upper shaft (10) and the hollow motor (12), and a lower planetary gear train (20) which transmits power between the lower shaft (11) and the hollow motor (12)
Data Source
AI summary
An adaptive front steering system is capable of ensuring steering convenience and driving safety by changing a steering gear ratio in accordance with a driving situation of a vehicle. The adaptive front steering system is implemented as a new type of active front steering (AFS) system in which a hollow motor is applied to a steering column shaft, and a steering gear ratio is changed in accordance with a rotation direction and a rotation amount of a shaft of the hollow motor which is rotated together with an upper shaft.