Electric Power Steering Ball Screw Torque Transmission
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Solution Overview
Problem
Hydraulic power steering systems used in trucks and buses, which require large steering forces, cannot support advanced features like automatic parking, lane keeping, and autonomous driving due to the absence of electronic control devices, and face durability issues with power transmission parts.
Innovation Solution
An electric power steering apparatus with a ball screw, ball nut, sector shaft, and sliding support member, coupled through a reducer, enhances torque transmission and durability, incorporating an electronic control device for motor operation and sensor integration to assist steering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hydraulic power steering apparatus is used to provide large steering force for trucks and buses, then steering force is sufficient, but electronic control functions (automatic parking, lane keeping, autonomous driving) cannot be implemented
Solution Approach 1:
The patent replaces the hydraulic power steering system with an electric power steering system that uses a motor to generate steering force. This substitution enables the integration of electronic control devices, sensors, and communication modules, allowing trucks and buses to implement advanced functions such as automatic parking, lane keeping, and autonomous driving while maintaining sufficient steering force.
2Force
If hydraulic power steering apparatus is used for large steering force applications, then steering capability is adequate, but durability of power transmission parts deteriorates
Solution Approach 1:
The patent optimizes the design parameters of power transmission components including the ball nut, ball screw, and sector shaft. By changing material parameters, geometric parameters, and operational parameters, the system achieves both high steering force capability and improved durability, preventing the deterioration that occurs in traditional hydraulic systems.
3Adaptability or versatility
If electric power steering apparatus is used to enable electronic control functions, then adaptability improves, but torque transmission capability for large vehicles deteriorates
Solution Approach 1:
The patent divides the power transmission system into modular components including a motor, reducer, ball screw mechanism, and sector shaft. This segmentation allows each component to be optimized independently - the motor provides electronic control capability while the reducer and ball screw mechanism amplify torque to meet the high power requirements of large vehicles like trucks and buses.
4Power
If reducer is added to transmit amplified steering torque, then torque transmission capability improves, but device complexity increases
Solution Approach 1:
The patent merges the reducer function with the ball screw mechanism into an integrated power transmission assembly. The motor connects directly to the ball screw through the reducer, combining multiple functions into a compact unit that transmits amplified steering torque while minimizing structural complexity and space 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
Enables efficient transmission of amplified steering torque and improves driver convenience by enhancing the durability of power transmission components, allowing for advanced vehicle control features like automatic parking and autonomous driving.
Implementation Method 1
a ball screw 210 having an outer screw groove 211 formed on an outer circumferential surface, a ball nut 220 having a gear portion 226 formed on one side of an outer circumferential surface and an inner screw groove 221 corresponding to the outer screw groove 211 formed on an inner circumferential surface
Implementation Method 2
a sliding support member 230 coupled to an outer circumferential surface of the ball nut 220, supported on an inner circumferential surface of a housing 135, and axially slid together with the ball nut
Data Source
AI summary
An electric power steering apparatus according to the embodiments of the present disclosure may comprise a ball screw having an outer screw groove formed on its outer circumferential surface, a ball nut having a gear portion formed on one side of the outer circumferential surface and an inner screw groove corresponding to the outer screw groove formed on the inner circumferential surface, coupled to the ball screw through a ball and sliding in the axial direction, a sector shaft having a shaft gear coupled to the gear portion of the ball nut on an outer circumferential surface and rotating when the ball nut slides in an axial direction, and a sliding support member coupled to the outer circumferential surface of the ball nut, supported on an inner circumferential surface of a housing, and axially slid together with the ball nut.