Steering Wheel Stowage Using a Planetary Gear and Reaction Motor
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Solution Overview
Problem
Current steering wheel stowing systems for steer-by-wire vehicles face limitations in movement range and space maximization due to the need for additional actuators, which also result in increased weight and cost, and lack rapid deployment capabilities essential for smooth driver steering during autonomous driving transitions.
Innovation Solution
A device utilizing a planetary gear set and reaction force motor to rapidly stow and deploy the steering wheel, with a sliding unit and telescopic motor, allowing for high-torque operation and emergency deployment, while eliminating the need for additional motors or actuators by leveraging existing steering system components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stowing actuator is added to move the steering wheel, then the steering wheel can be stowed, but the layout space is reduced and cost increases
Solution Approach 1:
The patent combines the stowing function with the existing reaction force motor that is already part of the steer-by-wire steering system. The reaction force motor serves dual purposes: providing reaction torque during steering operations and driving the steering wheel stowage through the planetary gear set. This eliminates the need for a separate stowing actuator, thereby reducing layout space and device complexity while maintaining stowage capability.
2Speed
If the actuator size is increased to enable rapid steering wheel deployment, then deployment speed improves, but weight and cost increase
Solution Approach 1:
The patent employs a planetary gear set that can dynamically switch between different operational modes through braking elements. The system can operate in motor-driven mode for controlled stowage/deployment, in high-speed free-wheeling mode for rapid deployment, and in locked mode for holding position. This dynamic capability allows rapid steering wheel deployment without requiring an oversized motor, as the gear set amplifies torque and enables high-speed operation when needed while keeping the motor size compact.
3Reliability
If a rotational stowing system is used, then the steering wheel can be moved, but the movement range is limited
Solution Approach 1:
The patent transitions from rotational stowing motion to linear sliding motion by incorporating a rack gear that converts the rotational output of the planetary gear set into linear displacement. This dimensional change allows the steering wheel to move along a longer linear path within the stowage space, significantly increasing the movement range compared to purely rotational systems while maintaining compact packaging.
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 rapid and safe stowage and deployment of the steering wheel, reducing weight and cost while maintaining space maximization effects, facilitating quick transitions between autonomous and driver-controlled driving modes.
Implementation Method 1
a planetary gear set having a first rotational element connected to the steering wheel and selectively locked by a first braking element, a second rotational element connected to a reaction force motor, and a third rotational element selectively locked by a second braking element
Implementation Method 2
a first rotational element connected to the steering wheel and selectively locked by a first braking element, a second rotational element connected to a reaction force motor, and a third rotational element selectively locked by a second braking element
Implementation Method 3
The sliding unit may include a rack gear disposed at an inner surface of the stowage space, which is formed in an interior of a vehicle and thus, the rack gear may extend in an axial direction of the steering wheel. The sliding unit may also include a pinion rotatably provided at the steering wheel module, the pinion being connected between the third rotational element and the rack gear in a gear engagement manner
Data Source
AI summary
A device for stowing a steering wheel and a control method thereof are provided. The device includes a steering wheel module having a steering wheel and the steering wheel module is movable to an interior of a stowage space together with the steering wheel. A planetary gear set are provided and include a first rotational element connected to the steering wheel and selectively locked by a first braking element, a second rotational element connected to a reaction force motor, and a third rotational element selectively locked by a second braking element. A sliding unit is configured to slide the steering wheel module into the stowage space using rotational force received from the third rotational element.