Inverter Layout for Slewing Motor Cable Length Reduction

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Solution Overview

Problem

The existing design of hydraulic excavators with slewing electric motors and inverters results in elongated high-tension cables that can interfere with control signal lines, leading to noise and increased installation costs.

Innovation Solution

Reconfiguring the layout by placing the inverter near the slewing motor in a side region, reducing the length of high-tension cables and protecting them from environmental factors, while also utilizing a slew assist electric motor to minimize the slewing hydraulic motor's capacity and optimizing the placement of control components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the inverter is disposed in the engine room at the rear of the center region, then the control device is positioned in a conventional location, but the high-tension cable becomes elongated and may approach or cross control signal lines causing noise interference

Engineering Contradiction:
Improvecontrol accuracyVSAvoidhigh-tension cable length
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The inverter is relocated from the engine room to the center region where the slewing motor is disposed, changing the spatial dimension of component arrangement. This repositioning in a different location dimension reduces the cable length and prevents interference with control signal lines, thereby improving control accuracy while maintaining conventional inverter functionality

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

2Ease of manufacture

If the high-tension cable is elongated to connect the slewing motor with the inverter in the engine room, then the components can be positioned according to conventional layout, but the installation expense increases and manufacturing cost rises

Engineering Contradiction:
Improveinstallation costVSAvoidhigh-tension cable length
Core Design Contradiction:
Ease of manufactureVSLength of stationary object

Solution Approach 1:

The inverter is merged with the slewing motor by disposing the inverter in the same center region and positioning it near the slewing motor. This spatial merging eliminates the need for long high-tension cables, reducing installation expense and manufacturing cost while maintaining the functional separation between the inverter and slewing motor

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2568086B1Electric work vehicle
Publication Date: 2021.12.01 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP2568086B1 patent drawingFigure 1
  • EP2568086B1 patent drawingFigure 2~3
  • EP2568086B1 patent drawingFigure 4

AI summary

[Problem] Provided is an electric work vehicle in which the length of a high-tension cable connecting an electric motor included in a slewing motor with an inverter for controlling the electric motor can be set to be comparatively short. [Means for Resolution] The invention is configured in such a manner that a region on a main frame 1 is divided into three regions consisting of a center region S, a first side region L, and a second side region R, by means of a first vertical rib 1a and a second vertical rib 1b, a slewing hydraulic motor 8 and a slew assist electric motor 21, which constitute the slewing motor, are disposed in the center region S, and an inverter 22 for controlling the slew assist electric motor 21 is disposed in a position near the second vertical rib 1b in a second tool chamber 13 provided in the second side region R, i.e. the inverter 22 is disposed in a position close to the slew assist electric motor 21.