Steer-By-Wire Screw Reducer Layout for Compact Low-Noise Torque Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional steer-by-wire steering devices face challenges with durability, power transfer efficiency, noise generation, and size due to the use of worm-worm wheel and ball nut reducers, which result in a bulky structure and reduced torque output, particularly affecting autonomous driving.
Innovation Solution
A steer-by-wire steering device featuring a sliding bar with a screw on its outer surface, a hollow first shaft for axial sliding, and a plurality of second shafts with screw shaft portions, along with a supporting member for coupling, which eliminates the need for balls and pulley-belt structures, allowing for a more compact design and enhanced power transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a ball nut reducer is used to reduce motor torque, then torque reduction is achieved, but the device becomes bulky and noise is generated due to ball circulation
Solution Approach 1:
The patent extracts and eliminates the balls from the ball nut reducer, retaining only the screw thread structure. This removes the noise-generating ball circulation mechanism while maintaining the torque reduction function through the screw thread engagement between the motor shaft and the rack bar.
Solution Approach 2:
The patent replaces the complex ball nut mechanical system with a simpler direct screw thread mechanism. This substitution eliminates the need for ball circulation paths and associated components, reducing device volume and noise while achieving the same torque reduction effect.
2Power
If a ball nut reducer is used to reduce motor torque, then torque reduction is achieved, but knocking sounds are generated during ball circulation
Solution Approach 1:
The patent extracts and eliminates the balls from the ball nut reducer, retaining only the screw thread structure. This removes the noise-generating ball circulation mechanism while maintaining the torque reduction function through the screw thread engagement between the motor shaft and the rack bar.
3Power
If a worm-worm wheel reducer is used, then torque reduction is achieved, but durability is weak and high power output is limited
Solution Approach 1:
The patent replaces the worm-worm wheel reducer with a screw thread mechanism directly integrated into the rack bar. This substitution improves durability by eliminating the weak worm gear connection while maintaining torque reduction capability through the self-locking property of the screw threads.
4Object-generated harmful factors
If the motor is spaced apart from the rack bar to reduce noise, then noise is reduced, but the device becomes bulky
Solution Approach 1:
The patent merges the motor shaft directly with the rack bar by integrating the screw thread structure into the rack bar itself. This eliminates the need for spacing between motor and rack bar, reducing device volume while maintaining noise reduction through the elimination of ball circulation.
5Power
If a pulley-belt reduction structure is added to achieve higher torque reduction, then reduction ratio is increased, but device complexity and size increase
Solution Approach 1:
The patent extracts and eliminates the pulley-belt reduction structure, achieving the required torque reduction through a single optimized screw thread mechanism integrated into the rack bar. This simplifies the device structure while maintaining the necessary reduction ratio.
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 reduces noise, increases power transfer efficiency and stability, and secures installation space by enabling a larger reduction ratio without additional components, improving driver convenience and motor performance.
Implementation Method 1
a sliding bar (102) provided to be axially slidable in a housing (101) and having a screw formed on an outer circumferential surface thereof
Data Source
AI summary
According to the embodiments of the present invention, the overall size reduction allows installation space to be advantageously secured, reduction in noise generated during operation improves the comfort of the driver, and the strength and stability of the connective structure between parts can be increased and power transmission can be more effective.