Backhoe Loader Steering Return Control Using Cylinder Displacement

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Solution Overview

Problem

Existing engineering vehicles, particularly backhoe loaders, lack an automatic return function in their hydraulic steering systems, making it difficult for drivers to determine the direction and position, leading to increased operation intensity and fatigue.

Innovation Solution

A steering system with a direction control device, including a steering wheel, steering cylinder, steerable wheels, displacement sensor, return motor, and controller, which automatically returns the steerable wheels based on piston displacement detection, enhancing the steering system's convenience and reducing driver effort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a full hydraulic steering system is used, then steering operations become light and convenient, but the steering wheel cannot achieve the limit of end points of turning left and right, making it difficult for the driver to determine the direction and position

Engineering Contradiction:
Improvesteering operation convenienceVSAvoiddriver's ability to determine direction and position
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent introduces a steering angle sensor that detects the steering wheel angle and provides feedback to the controller. The controller then controls the electric motor to adjust the steering wheel angle, creating a closed-loop feedback system that enables the driver to accurately determine the steering wheel's position and achieve precise turning limits while maintaining the convenience of hydraulic power steering.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If a full hydraulic steering system is used, then steering operations become light and convenient, but frequent steering operations increase driver fatigue without an automatic return function

Engineering Contradiction:
Improvesteering operation convenienceVSAvoiddriver operation efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent implements an automatic return function where the steering system automatically returns the steering wheel to the central position after steering operations. The controller detects when steering input is released and automatically actuates the electric motor to return the steering wheel, eliminating the need for manual return operations and reducing driver fatigue during frequent steering maneuvers.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical return operations with an electric motor-driven automatic return system. The electric motor, controlled by the controller, substitutes for the driver's manual effort in returning the steering wheel, thereby improving operation efficiency and reducing fatigue while maintaining the light and convenient characteristics of hydraulic power steering.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If manual steering return is required, then the system structure remains simple, but the driver must continuously monitor and manually return the steering wheel, increasing operation intensity

Engineering Contradiction:
Improvesteering system structureVSAvoiddriver operation intensity
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent uses a steering angle sensor to provide continuous feedback on the steering wheel's position to the controller. This feedback mechanism enables the system to automatically detect when steering input is released and initiate the return process, reducing the need for continuous driver monitoring while maintaining relatively simple system architecture through the use of standard sensing and control components.

Inventive Principle:
Principle #23Feedback

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

The system enables automatic return of steerable wheels, reducing driver operation intensity and improving manipulation comfort by accurately positioning the steering cylinder, thus enhancing steering system usability.

Implementation Method 1

a displacement sensor configured to detect a piston displacement of the steering cylinder

Methodology Applied
Scientific EffectDisplacement detection: Displacement

Implementation Method 2

a hydraulic pump; and a full hydraulic steering device, with an oil inlet and an oil return port of the full hydraulic steering device being respectively connected with an oil outlet of the hydraulic pump

Methodology Applied
Scientific EffectHydraulic pressure transmission: Hydraulic Press

Data Source

PatentEP3984860B1Steering system of engineering vehicle and backhoe loader
Publication Date: 2026.01.21 JIANGSU XCMG CONSTRUCTION MACHINERY RESEARCH INSTITUTE LTD
  • EP3984860B1 patent drawingFigure 1

AI summary

The present disclosure provides a steering system of an engineering vehicle, and a backhoe loader. The steering system includes: a direction control device, including a steering wheel, a steering cylinder and steerable wheels, the steering cylinder being in transmission connection with the steering wheel and the steerable wheels; a displacement sensor configured to detect a piston displacement of the steering cylinder; a return motor in transmission connection with the steerable wheels to drive the steerable wheels to return to a normal position; and a controller in signal connection with the displacement sensor and the return motor, and configured to output a control signal according to the piston displacement detected by the displacement sensor to manipulate the return motor to drive the steerable wheels to return. The backhoe loader includes the steering system.