Ball Screw Electric Power Steering for Heavy-Duty Automation
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Solution Overview
Problem
Existing hydraulic power steering systems in trucks and buses lack the ability to perform automatic parking, lane-keeping, and autonomous driving functions due to the absence of an electronic control device, and require improved durability and convenience in power transmission components.
Innovation Solution
An electric power steering apparatus with a ball screw, ball nut, sector shaft, and gearbox housing, utilizing a speed reducer to amplify steering torque and enhance durability of components like the ball nut, ball screw, and housing, while incorporating an electronic control device for enhanced functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hydraulic power steering apparatus is used to provide high steering force for trucks and buses, then steering force is sufficient, but automatic parking and autonomous driving functions cannot be implemented due to lack of electronic control device
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 integration of electronic control devices while maintaining sufficient steering force for trucks and buses, thereby enabling automatic parking and autonomous driving functions.
Solution Approach 2:
The electric power steering apparatus is designed to serve multiple functions: it provides high steering force for manual operation, enables electronic control for automatic parking, supports lane-keeping assistance, and facilitates autonomous driving. This multi-functionality is achieved by integrating the motor, speed reducer, and electronic control device into a unified system.
2Ease of operation
If hydraulic pump and operation cylinder are used to assist steering, then steering assistance is provided, but durability of power transmission components is insufficient
Solution Approach 1:
The patent replaces the hydraulic pump and operation cylinder with a motor-driven ball screw mechanism. This substitution improves the durability of power transmission components by eliminating hydraulic fluid leakage issues, reducing maintenance requirements, and providing more reliable mechanical power transmission through the ball screw and nut assembly.
3Extent of automation
If electric power steering apparatus is implemented to enable automatic parking function, then automation capability is improved, but steering force may be insufficient for trucks and buses
Solution Approach 1:
The patent incorporates a speed reducer in the power transmission path to amplify the motor output torque before it reaches the steering mechanism. This preliminary mechanical advantage ensures that the motor can generate sufficient steering force for trucks and buses while maintaining the ability to implement automatic parking and other automated functions through electronic control.
4Force
If speed reducer is added to amplify steering torque, then steering force is increased, but device complexity increases
Solution Approach 1:
The patent integrates the speed reducer directly into the ball screw mechanism, combining the torque amplification function with the existing power transmission components. This merging approach minimizes additional structural complexity while achieving the required steering torque amplification for heavy-duty vehicles.
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 trucks and buses to perform automatic parking, lane-keeping, and autonomous driving functions, while improving the durability and convenience of power transmission components.
Implementation Method 1
a ball screw operably coupled to a steering shaft, configured to be rotatable, and having an outer screw groove provided on an outer surface of the ball screw; a ball nut having an inner screw groove provided on an inner surface of the ball nut
Implementation Method 2
having gear teeth provided on an outer surface of the ball nut and coupled to a sector shaft
Data Source
AI summary
Provided are an electric power steering apparatus and a vehicle having the same, the electric power steering apparatus including a ball screw coupled to a steering shaft, configured to rotate, and having an outer peripheral screw groove provided in an outer peripheral surface thereof, a ball nut having an inner peripheral screw groove provided in an inner peripheral surface thereof and corresponding to the outer peripheral screw groove, having outer peripheral gear teeth provided on an outer peripheral surface thereof and coupled to a sector shaft, and configured to slide in an axial direction if the ball screw rotates, a gearbox housing in which the ball screw, the sector shaft, and the ball nut are embedded, and a nut slider coupled to the outer peripheral surface of the ball nut and configured to slide while being supported on an inner peripheral surface of the gearbox housing if the ball nut slides.