Ball Screw Electronic Power Steering for Commercial Vehicles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electric power steering systems provide insufficient steering assistance for commercial vehicles like trucks and buses, which require larger steering forces, and are not capable of implementing advanced driver assistance functions such as automatic parking, lane maintenance, and autonomous driving.
Innovation Solution
An electronic steering device featuring a reduction gear connected to a drive motor, a ball screw, and a ball nut with gear teeth, allowing for enhanced steering power and integration of driver assistance functions, including automatic parking and autonomous driving, through independent control of dual drive motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hydraulic steering system is used, then steering power is sufficient for commercial vehicles, but electronic control functions (automatic parking, lane maintenance, autonomous driving) cannot be implemented
Solution Approach 1:
The patent replaces the hydraulic power steering system with an electric power steering system using a motor-driven ball screw mechanism. This substitution enables electronic control functions while providing sufficient steering power for commercial vehicles through the mechanical advantage of the ball screw and reduction gear.
Solution Approach 2:
The patent changes the fundamental operating parameter from hydraulic pressure to electric motor torque, allowing integration of electronic control systems while maintaining the mechanical force output needed for commercial vehicle steering through optimized motor selection and ball screw geometry.
2Adaptability or versatility
If conventional electric steering apparatus is used, then electronic control functions can be implemented, but steering assistance power is insufficient for commercial vehicles
Solution Approach 1:
The patent employs a ball screw mechanism where spherical balls roll between the screw threads, converting rotational motion to linear motion with high mechanical efficiency. This curved geometric interaction multiplies the motor torque to provide sufficient steering assistance power for commercial vehicles.
Solution Approach 2:
The patent adds a reduction gear stage between the motor and ball screw, introducing an additional dimensional transformation that multiplies torque output. This gear reduction enables the motor to deliver the high steering assistance power required for commercial vehicles while maintaining electronic controllability.
3Force
If hydraulic pump and operating cylinder are used, then steering assistance is provided, but system complexity and maintenance requirements increase
Solution Approach 1:
The patent replaces the complex hydraulic system (pump, hoses, operating cylinder, fluid reservoir) with a more compact electric motor and ball screw assembly. This substitution reduces system complexity, eliminates hydraulic fluid maintenance requirements, and improves reliability while providing equivalent or superior steering assistance.
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 electric power steering for commercial vehicles, enhances driver convenience, and improves safety by securing redundancy with dual motors, enabling steer-by-wire systems and advanced driver assistance functions.
Implementation Method 1
a ball screw rotatable in conjunction with the output shaft, wherein the ball screw has an upper end coupled to a lower end of the output shaft, and wherein the ball screw has outer peripheral screw threads formed on an outer peripheral surface thereof
Implementation Method 2
a ball nut having gear teeth formed on an outer peripheral surface thereof and inner peripheral screw threads formed on an inner peripheral surface thereof, wherein the inner peripheral screw threads correspond to the outer peripheral screw threads, wherein the ball nut is coupled to the ball screw via a ball, and wherein the ball nut slides in an axial direction
Data Source
AI summary
An electronic power steering apparatus, according to one embodiment of the present invention, comprises: an output shaft rotated by means of a reduction gear connected to a driving motor; a ball screw having an upper end coupled to a lower end of the output shaft, and having outer circumferential screw grooves formed on an outer circumferential surface thereof to rotate in conjunction with the output shaft; a ball nut having gear teeth formed on an outer circumferential surface thereof and inner circumferential screw grooves corresponding to the outer circumferential screw grooves formed on an inner circumferential surface thereof, the ball nut being coupled to the ball screw via a ball and sliding in an axial direction; and a sector shaft, coupled to the gear teeth of the ball nut, for operating a pitman arm while rotating during the axial sliding of the ball nut.