Integrated Electric Power Steering for Hydrostatic Backup Control
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Solution Overview
Problem
Existing electric power steering devices for heavy vehicles, such as tractors and earth moving machines, require a compact design that integrates hydrostatic steering and electrically assisted steering systems while ensuring easy installation and precise control, especially when the hydrostatic system malfunctions.
Innovation Solution
The electric power steering device incorporates a steering column with a tiltable base and upper segment, an articulated steering axis, a hydrostatic steering assembly, and an electrically assisted steering apparatus with a support frame, shaft, and electric motor, allowing for compact longitudinal design and precise control through a torsion bar and joint system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric power steering device integrates hydrostatic steering and electrically assisted steering systems, then the system provides backup steering capability and precise control, but the device complexity increases
Solution Approach 1:
The patent combines hydrostatic steering and electrically assisted steering systems into a single integrated steering device. The EPS motor and hydrostatic components share a common housing and are mechanically coupled through a differential mechanism, allowing both systems to work together in a unified structure rather than as separate assemblies.
Solution Approach 2:
The steering device is designed to perform multiple functions through a single integrated system. The differential mechanism allows the device to operate in hydrostatic mode for normal steering, EPS mode for precision control, and manual mode for backup operation, making the system versatile and adaptable to different operating conditions.
2Ease of operation
If the steering column is designed with tiltable base and upper segment for adjustability, then the ease of operation improves, but the device complexity increases
Solution Approach 1:
The steering column is designed with dynamic adjustability features. The upper segment can tilt relative to the base through a hinge connection, and the steering wheel can be positioned at different angles. These dynamic adjustments allow the operator to customize the steering position for comfort and ease of operation.
3Length of moving object
If the electric motor is positioned with annular rotor and stator in the EPS apparatus, then the compact longitudinal design is achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The electric motor is designed with a nested annular structure where the rotor is positioned inside the stator. This concentric arrangement allows the motor to be compact in the radial direction while maintaining adequate length axially. The annular components are precisely fitted together to minimize gaps and ensure efficient magnetic coupling.
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 results in a compact, versatile, and easily installable electric power steering device that provides precise control and easy maintenance, ensuring efficient operation even when the hydrostatic system is malfunctioning.
Implementation Method 1
an electric motor comprising an annular rotor constrained in rotation to the shaft and an annular stator that coaxially surrounds the annular rotor
Implementation Method 2
the wheels of the vehicles are steered by means of a hydraulic actuator, for example a double-acting hydraulic cylinder, which is connected with a hydraulic fluid reservoir through a pump and a hydraulic steering unit
Implementation Method 3
allowing, at the same time, to provide the installer with a product that is already assembled and ready for installation on the vehicle
Data Source
AI summary
An electric power steering device includes: —a steering column provided with: a base; an upper segment connected in a tiltable manner to the base, a steering axis comprising a lower axis rotatably contained inside the base; —a hydrostatic steering assembly; —an electrically assisted steering apparatus axially interposed between the steering column and the hydrostatic steering assembly and provided with: a support frame comprising a tubular central body; a shaft whose upper end axially projects outside an upper end of the central body and is connected to the lower end of the lower axis and whose lower end is connected to the hydrostatic steering assembly; and an electric motor positioned inside the central body of the support frame; in which the upper end of the central body is directly fixed to the base and in contact therewith.