Cab-Tilt Power Interruption in Electric Work Machines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electrically driven work machines, such as hydraulic excavators, maintenance efficiency is reduced due to residual voltage in the electrical system when the prime mover is stopped but the key switch remains in the on-state, requiring careful attention to voltage levels during maintenance.
Innovation Solution
The electrically driven work machine incorporates a control power interruption device that disconnects power to the inverter, power feed system, and driving battery device when the cab is tilted up, using a sensor to detect the tilted-up state and ensure power interruption regardless of the key switch state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the key switch is in the on-state during maintenance, then the electrical system remains powered for operational readiness, but maintenance safety is compromised due to residual voltage
Solution Approach 1:
The control power interruption device is activated in advance when the cab is tilted up for maintenance, automatically cutting off power to the inverter and electrical system before maintenance personnel begin work. This preliminary action ensures that even if the key switch is in the on-state, the electrical system is de-energized during maintenance, eliminating the residual voltage hazard while maintaining operational readiness when the cab is in its normal position.
2Ease of operation
If the cab is tilted up to expose maintenance target parts, then maintenance accessibility is improved, but electrical system safety is worsened due to remaining voltage
Solution Approach 1:
The control power interruption device serves as an intermediary between the cab tilt-up action and the electrical system. When the cab is tilted up, the sensor detects this position and automatically activates the power interruption device, which mediates by cutting off power to the inverter and electrical components. This allows maintenance personnel to safely access exposed parts without dealing with residual voltage, while maintaining the ability to quickly restore power by returning the cab to its normal position.
3Extent of automation
If a sensor detects cab tilt-up position, then automatic power interruption is enabled, but device complexity increases
Solution Approach 1:
The sensor and control power interruption device work together in a self-service manner where the sensor automatically detects when the cab is tilted up and triggers the power interruption without requiring manual intervention from the operator. The system serves itself by using the cab's own position as the trigger signal, eliminating the need for complex manual control mechanisms while achieving automatic safety protection.
Data Source
AI summary
There is provided an electrically driven work machine including an electric motor that is a prime mover, an inverter that controls the electric motor, a power feed system that supplies power to the inverter, a driving battery device that stores the power supplied from the power feed system and supplies the power to the inverter, a control battery that supplies power for control for the inverter, the power feed system, and the driving battery device, and an opening-closing cover that covers the power feed system. The electrically driven work machine includes a control power interruption device that interrupts supply of the power for control with respect to the inverter, the power feed system, and the driving battery device in conjunction with opening of the opening-closing cover.