Steering Feedback Actuator Gear Layout for Compact High Reduction
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Solution Overview
Problem
Conventional power steering systems have complex structures and require multiple parts, while steer-by-wire (SBW) systems face challenges in reducing size and achieving high deceleration ratios.
Innovation Solution
A steering feedback actuator design featuring a housing, cover, motor, sun gear, ring gear, planet gear, carrier, and fixing member, with specific geometries and assembly mechanisms to prevent interference and enhance deceleration ratio within a limited space, while reducing assembly complexity and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional power steering system uses a fluid pressure type steering system with an oil pump, then steering assistance power is generated, but the system requires multiple parts and has a complicated structure
Solution Approach 1:
The patent replaces the fluid pressure type mechanical steering system with an electric motor-based steer-by-wire system. The motor (300) directly provides steering assistance torque through a deceleration mechanism, eliminating the need for oil pumps, fluid pressure channels, and multiple mechanical components, thereby reducing structural complexity while maintaining steering assistance power
Solution Approach 2:
The patent extracts and removes the fluid pressure generation components (oil pump, reservoir, hoses) from the steering system. By using an electric motor to directly generate steering torque, the system eliminates the entire fluid pressure subsystem, achieving a simpler structure with fewer parts
2Volume of moving object
If the SBW system uses a feedback motor connected to the steering wheel, then feedback is provided to the steering wheel, but the size reduction and high deceleration ratio are challenging
Solution Approach 1:
The patent implements a nested planetary gear deceleration mechanism where the planet gear (430) is positioned between the sun gear (410) and ring gear (420). This nested arrangement achieves high deceleration ratio within a compact volume, as the planet gear rotates on its own axis while simultaneously orbiting the sun gear, maximizing torque multiplication in minimal space
Solution Approach 2:
The patent uses a three-dimensional planetary gear configuration that exploits radial and axial dimensions simultaneously. The sun gear rotates centrally, planet gears orbit radially while rotating on their axes, and the ring gear provides outer containment, creating a compact cylindrical deceleration mechanism that achieves high reduction ratios without increasing overall footprint
3Volume of moving object
If the motor and deceleration member are disposed close together, then space is saved, but interference between the motor and deceleration member occurs
Solution Approach 1:
The patent segments the internal housing space into distinct functional zones using a barrier rib (140). The first accommodation part (120) houses the motor while the second accommodation part (130) contains the deceleration mechanism. This segmentation prevents interference between rotating components while maintaining compact overall dimensions by efficiently utilizing vertical space separation
4Reliability
If grease is used in the deceleration mechanism, then lubrication is provided, but grease may enter the motor and cause damage
Solution Approach 1:
The patent extracts the lubrication function from the motor environment by confining grease exclusively to the deceleration mechanism compartment (130). The barrier rib (140) acts as a physical extraction boundary that prevents grease migration toward the motor, allowing full lubrication of gear components without exposing the motor to harmful contaminants
Solution Approach 2:
The barrier rib (140) serves as an intermediary structure between the motor and deceleration mechanism. This intermediate partition allows the system to simultaneously achieve proper lubrication of moving parts while protecting the motor from grease contamination, acting as a protective mediator that separates incompatible environmental requirements
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 design prevents motor interference and damage from grease, enhances deceleration ratio, reduces noise and durability issues, and simplifies assembly, leading to a more compact and cost-effective SBW system.
Implementation Method 1
a sun gear connected to the motor, a ring gear disposed to surround the sun gear, a planet gear disposed between the sun gear and the ring gear
Implementation Method 2
a barrier rib disposed between the first accommodation part and the second accommodation part
Data Source
AI summary
The steering feedback actuator includes a housing, a cover disposed to face the housing, a motor disposed within the housing, a sun gear connected to the motor, a ring gear disposed to surround the sun gear, a planet gear disposed between the sun gear and the ring gear, a carrier connected to the planet gear and rotated in conjunction with a rotation of the planet gear, and a fixing member provided between the cover and the ring gear and configured to fix the cover to the ring gear.