1. High Mobility and Productivity
We coupled the AC drive system, which has a high load-responsive IGBT inverter, with drive control software that was jointly developed with other Hitachi Group companies, to achieve a system that excels in controlling travel motor speed and torque. Whether taking off from a standstill, ascending grades, or performing steering maneuvers, the system delivers an optimal, individual amount of power to each of the travel motors for smooth, quick operation.
In addition to adding various sensors that detect vehicle motion, this is the first time in this class of machinery that we employed the Hitachi Drive Control System which aims to achieve higher drive control performance by reducing tire slippage on acceleration and tire lock-up during braking, and preventing chassis oscillation in a front-rear direction and tire skid while steering. Consequently, we realized strong and steady travel performance that ensures more stable jobsite haul-cycle times which contributes to higher productivity.
These two models also boast powerful electric brakes that are activated during downhill driving. Since this dump truck does not require the use of mechanical brakes during normal driving, not only is deceleration smoother but maintenance for the mechanical brakes is required less frequently.
In the wide-berth cab, which is capable of housing two full-size seats, a large LCD display is located at the base of the handle. The display is in clear view and quickly provides the operator with information and warnings on drive operations such as traveling speed, engine turnover, and hauling performance. In addition, the multilingual display allows users to view information and warnings in their own language, thereby contributing to improved serviceability and safety.
Thanks to a powerful electric brake, the dump trucks can be normally operated using two pedals, one for acceleration and one for the brakes. Easier operability alleviates operator fatigue.
We located the levers and switches for operating the body the center console, making it possible operate the body with one hand.
3. High Reliability and Safety
The mainframe’s structural design, including the cab support, is improved and fortified based on operating information we gathered on conventional models being used around the world.
We added a temperature sensor to the bearing area of the alternator and drive motor, which are the main components of the AC drive system developed in cooperation with other Hitachi Group companies. An alarm sounds when the sensor detects abnormal heat emission, and restricts driving operations to prevent sudden damage to the machine.
Improvements were made to the nominal payload measurement system. Measurement errors have been reduced by reflecting changes in fuel weight within the fuel tank into the nominal payload. In this fashion, we are working to further improve the reliability of production volume measurements at mining sites.
ROPS and FOPS are built into every truck cab as a standard safety requirement to withstand the impact of falling objects or a truck rollover. Other standard safety features include two mirrors with a front and rear view cameras to provide extensive truck perimeter visibility, ample 630mm width truck access stairways, and four engine stop switches located outside the cab to allow the operator to turn off the engine in an emergency situation during maintenance. In addition, we took advantage of the wide cab feature to provide more ample foot space to improve the operating environment.
The optional Peripheral Vision Support System feature provides another view to support the operator.
4. Superior Maintainability and Interchangeability
We are now offering customers the option of choosing between the standard feature Cummins Inc. engine and one by MTU Friedrichshafen GmbH. With the exception of North America where there are exhaust gas restrictions, to respond to the voice of customers worldwide, we are offering a choice of engines to contribute to an improvement in productivity and maintainability.
The evacuator exhaust valve for the engine suction filter and electric grease pump are among the new features we added to further improve daily maintainability.
Other standard features for maintainability include a trailing arm front suspension that permits strut removal without tire removal, a centralized auto-grease system can be accessed from the ground, a battery and relay box located in the front bumper for easy access, and a maintenance deck in the rear of the cab.
We also achieved a high level of interchangeability for common engine and hydraulic system components used in AC drive dump trucks and ultra large hydraulic excavators.