Wheel Loader Bucket Angle Control on Inclined Ground

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Solution Overview

Problem

Existing wheel loaders fail to prevent load material spillage during transitions from flat ground to inclined ground travel due to inadequate bucket angle adjustments based on ground inclination, leading to potential spillage even with operator oversight.

Innovation Solution

A wheel loader equipped with sensors to detect bucket, lift arm, and vehicle body angles, along with a controller that automatically adjusts the bucket angle to maintain a constant orientation relative to the ground, preventing spillage during changes in terrain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the wheel loader uses a link mechanism with the lift arm to position the bucket, then the bucket can be raised to position above the dump truck vessel, but the bucket angle becomes non-constant relative to the ground causing inclination and spillage

Engineering Contradiction:
Improvebucket position heightVSAvoidbucket angle stability
Core Design Contradiction:
Length of moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies dynamics by making the bucket angle adjustable rather than fixed. The bucket angle is dynamically changed based on detected ground inclination to maintain a constant bucket-to-ground angle, preventing spillage while allowing the bucket to reach the required position height.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the bucket angle parameter based on ground inclination detection. When the ground is inclined, the bucket angle is adjusted to compensate, maintaining a constant effective angle relative to the ground surface and preventing load material spillage.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the wheel loader operates on inclined ground without adjusting bucket angle, then the operation is simple, but load materials spill from the bucket

Engineering Contradiction:
Improveoperation simplicityVSAvoidspillage prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs self-service by automatically detecting ground inclination and adjusting the bucket angle without operator intervention. The control unit automatically commands the bucket actuator to change the bucket angle based on sensor data, eliminating the need for manual adjustment while preventing spillage.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent implements feedback by using sensors to detect ground inclination and bucket angle, then feeding this information to the control unit which adjusts the bucket angle accordingly. This closed-loop control ensures the bucket maintains the optimal angle relative to the ground surface.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If the wheel loader switches from flat ground to inclined ground traveling, then the vehicle can adapt to terrain changes, but spillage occurs if the bucket angle is not adjusted

Engineering Contradiction:
Improveterrain adaptabilityVSAvoidspillage prevention during transition
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system takes preliminary action by detecting ground inclination changes and automatically adjusting the bucket angle before spillage can occur. The control unit continuously monitors ground conditions and proactively changes the bucket angle to maintain proper loading orientation during terrain transitions.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4001514B1Work vehicle
Publication Date: 2026.02.25 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP4001514B1 patent drawingFigure 1
  • EP4001514B1 patent drawingFigure 2
  • EP4001514B1 patent drawingFigure 3

AI summary

Provided is a work vehicle capable of preventing spillage of load materials from a bucket, even without adjusting an angle of the bucket in a scene where a traveling state is switched from a flat ground traveling to an inclined ground traveling. In a wheel loader 1 comprising a bucket 21 provided on the front of a vehicle body to scoop and discharge a work object, an inclination sensor 33 for detecting an inclination angle θ of the vehicle body is provided, and the controller 6 is configured to, in the case where a height position of the bucket 21 is higher than a predetermined height and it is determined that the vehicle body is in a state of being inclined rearward, activate a bucket cylinder 22 to a side for causing the bucket 21 to dump and correct an angle of the bucket 21.