Mini Excavator Accumulator Layout for Protected Compact Installation

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Solution Overview

Problem

Small hydraulic excavators face challenges in compactly integrating accumulators due to limited space and the need for protection from external forces during operations like excavation, as conventional techniques require increased counterweight size and are not applicable to mini excavators with restricted dimensions.

Innovation Solution

The accumulator is disposed along a longitudinal board member within the main frame, protected by a valve block and positioned between the longitudinal board member and the valve block, allowing for efficient use of limited space and protection from external forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the upper structure and track roller assembly are separated into independent swingable units, then the shovel can achieve compact configuration for narrow sites, but the structural complexity increases

Engineering Contradiction:
Improveconfiguration compactnessVSAvoidstructural complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The upper structure is divided into multiple independently swingable modules: the track roller assembly can swing relative to the upper frame, and the upper structure itself can swing relative to the track. This segmentation allows each module to be positioned independently to achieve compact configurations while maintaining structural integrity through standardized connection interfaces.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic positioning capabilities where the track roller assembly and upper structure can swing to different angles based on operational requirements. This dynamic adjustment allows the shovel to transition between extended working configurations and compact storage configurations, optimizing space utilization without permanent structural modifications.

Inventive Principle:
Principle #15Dynamics

2Length of stationary object

If the track roller assembly is positioned at the rear end of the upper frame, then the overall width is reduced for narrow sites, but the track roller assembly becomes prone to collision with obstacles

Engineering Contradiction:
Improveoverall widthVSAvoidcollision resistance
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The track roller assembly is equipped with active swing capabilities that allow it to dynamically adjust its position and orientation in response to detected obstacles or changing work conditions. This dynamic positioning enables the assembly to avoid collisions by swinging away from obstacles while maintaining its compact rear-end positioning for narrow site operations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates sensors and control mechanisms that detect obstacles and automatically trigger swing movements of the track roller assembly. This feedback-based control system allows the assembly to respond to environmental conditions in real-time, reducing collision risk while maintaining the space-efficient rear-end positioning.

Inventive Principle:
Principle #23Feedback

3Stability of the object's composition

If a large-sized counterweight is installed to ensure stable operation, then stability is improved, but the shovel cannot enter narrow construction sites

Engineering Contradiction:
Improveoperational stabilityVSAvoidshovel size
Core Design Contradiction:
Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The counterweight is designed with swing capabilities that allow it to dynamically adjust its position relative to the upper frame. During operational phases, the counterweight can be positioned to maximize stability. When entering narrow sites, the counterweight can be swung to a retracted or folded position, reducing the overall envelope of the shovel to fit through tight spaces while maintaining stability through active positioning during work.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The counterweight structure serves multiple functions: it provides ballast for stability during operation, can be repositioned to reduce width for narrow site access, and may incorporate additional functional elements. This multi-functionality allows the same component to address both stability requirements and space constraints without requiring separate dedicated structures.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables the placement of accumulators in small hydraulic excavators with limited installation space, ensuring effective energy recovery and protection during operations, while also reducing pipe length and optimizing device arrangement.

Implementation Method 1

a hydraulic cylinder (22) for extending and retracting

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP3447197B1Compact hydraulic shovel
Publication Date: 2021.01.20 HITACHI CONSTRUCTION MACHINERY TIERRA CO LTD
  • EP3447197B1 patent drawingFigure 1
  • EP3447197B1 patent drawingFigure 2
  • EP3447197B1 patent drawingFigure 3

AI summary

To provide a small hydraulic excavator, which even may have an upperstructure formed such that at least its rear end swings within a body width range and having a limited installation space for devices, that allows an accumulator to be disposed and allows the accumulator to be protected from external force generated during work. The present invention relates to a rear small-swing type mini excavator that includes an accumulator 30 accommodating and recovering potential energy and hydraulic energy used by at least one of drives of an undercarriage 1, an upperstructure 2 formed such that its rear end swings within the body width range of the undercarriage 1, and a working device 3. In the rear small-swing type mini excavator, the accumulator 30 is disposed between a valve block 26 and a front longitudinal board 41 of a longitudinal board member included in a main frame 10 along the front longitudinal board 41, and a pipe connected to the accumulator 30 and the valve block 26 is disposed closer to the accumulator 30 and the valve block 26.