Air conditioning unit for the cabin of a construction machine

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Solution Overview

Problem

The maintenance of outdoor air filters in construction machines, such as hydraulic excavators, is labor-intensive and prone to moisture issues, leading to reduced filter lifespan and potential indoor unit nonconformity due to rainwater or carwash water penetration.

Innovation Solution

The outdoor air duct is configured to pass between the cab box side face and the operator's seat, with a filter accommodation portion inside the cab box, allowing easy attachment and removal of the outdoor air filter without external access, and featuring an inverted U-shape to prevent moisture adhesion and penetration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the outdoor air filter is arranged at the outdoor air inlet port on the rear side of the cab box, then the filter can effectively trap dusts in outdoor air, but maintenance work requires workers to go around the outside of the cab box causing increased labor and time consumption

Engineering Contradiction:
Improveease of maintenanceVSAvoidmaintenance time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The outdoor air filter is relocated from the rear exterior position to the interior of the cab box, changing the spatial dimension of filter placement. The filter accommodation portion is formed in the outdoor air duct inside the cab box, allowing maintenance to be performed from the interior space rather than requiring exterior access.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The cab box interior space is utilized for dual purposes: as the operator's room and as the accommodation space for the outdoor air filter. This multi-functional use of the cab box interior eliminates the need for separate exterior filter housing and simplifies maintenance access.

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

2Reliability

If the outdoor air filter is provided at the outdoor air inlet port, then the filter can trap dusts, but rainwater or carwash water may adhere to the filter reducing its lifespan and potentially causing moisture penetration to the indoor unit

Engineering Contradiction:
Improvefilter lifespanVSAvoidmoisture adhesion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The outdoor air filter is extracted from the outdoor air inlet port position and relocated to the interior of the cab box. This separation removes the filter from the direct path of rainwater and carwash water, eliminating the harmful moisture adhesion while maintaining the filter's dust-trapping function through the indoor-accessible accommodation portion.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If the outdoor air duct is configured to pass between the cab box side face and operator's seat with an inverted U-shape, then the filter accommodation portion can be positioned inside the cab box for easy maintenance, but the duct configuration becomes more complex

Engineering Contradiction:
Improveease of filter accessVSAvoidduct configuration
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The outdoor air duct is designed with an inverted U-shape configuration that dynamically adapts to the cab box interior space constraints. The duct rises from the outdoor air inlet port, bends upward to position the filter accommodation portion inside the cab box, and then descends to connect to the indoor unit, flexibly navigating around the operator's seat and cab box structure.

Inventive Principle:
Principle #15Dynamics

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 simplifies maintenance, extends filter life, and protects the indoor unit from moisture, enhancing workability and reliability by allowing easy filter access and positioning the filter away from the outdoor air inlet port to prevent moisture adhesion.

Implementation Method 1

an outdoor air filter for trapping dusts in outdoor air flowing through the outdoor air duct

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP2674310B1Air conditioning unit for the cabin of a construction machine
Publication Date: 2019.11.13 HITACHI CONSTRUCTION MACHINERY TIERRA CO LTD
  • EP2674310B1 patent drawingFigure 1
  • EP2674310B1 patent drawingFigure 2
  • EP2674310B1 patent drawingFigure 3

AI summary

An upper revolving structure (3) is provided with a revolving frame (5), a floor member (10), and a cab box (20). On this, an indoor unit (21) for an air conditioner is provided on the floor member (10), and an outdoor air inlet port (16) is provided by being opened to the outside of the cab box (20). An outdoor air duct (24) is provided for supplying outdoor air introduced through the outdoor air inlet port (16) toward the indoor unit (21). In this duct (24), an intermediate portion (24A) is arranged at a high position on the side of an operator's seat (17), and on this intermediate portion (24A), a filter accommodating portion (26) is provided by being opened into the cab box (20). In the filter accommodating portion (26), an outdoor air filter (28) for trapping dusts in the outdoor air flowing through the outdoor air duct (24) is accommodated capable of being attached and removed.