Power Shovel Hydraulic Pump Layout for Lower Motor Energy Use
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Solution Overview
Problem
Conventional hydraulic control devices for construction machines, such as power shovels, require multiple electric motors and pumps, leading to increased energy consumption, cost, and complexity due to the need for multiple inverters and additional space, as well as inefficient oil supply and energy usage.
Innovation Solution
The implementation of a hydraulic control device with two sets of variable hydraulic pumps driven by separate electric motors, where primary pumps supply oil to main actuators and secondary pumps supply oil to sub-actuators and pilot pressure, allowing for optimized energy use and reduced unnecessary oil supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple electric motors and hydraulic pumps are used to control different actuators, then the control precision and adaptability of oil supply to each actuator is improved, but the device complexity and cost increase due to multiple inverters and additional components
Solution Approach 1:
The patent combines multiple hydraulic pumps into a single integrated pump unit that serves multiple actuators. This pump includes multiple plunger groups that can be independently controlled, merging the functions of what would traditionally require separate pumps and inverters, thereby reducing device complexity while maintaining control precision
Solution Approach 2:
The single hydraulic pump is designed with multi-functionality to serve multiple actuators including travel motors, boom cylinder, arm cylinder, bucket cylinder, and swinging cylinder. The pump can selectively supply oil to different actuators based on operational needs, providing universal control capability without requiring dedicated pumps for each actuator
2Device complexity
If a single electric motor drives all hydraulic pumps, then the device complexity is reduced, but energy consumption increases due to inefficient oil supply and unnecessary energy use
Solution Approach 1:
The hydraulic pump employs variable displacement plunger groups that can dynamically adjust their oil supply quantity based on the actual needs of different actuators. The control system selectively actuates specific plunger groups depending on which actuators require operation, enabling dynamic energy optimization rather than continuous full-capacity operation
Solution Approach 2:
The system changes operational parameters by selectively engaging different plunger groups within the pump for different operational modes. For example, only the first plunger group operates during travel, while both first and second plunger groups operate during excavation, optimizing energy consumption by matching pump output to actual workload requirements
3Speed
If hydraulic pumps continuously supply oil to all actuators, then the readiness and response time of the system is improved, but energy consumption and unnecessary oil supply increase
Solution Approach 1:
The hydraulic pump is segmented into multiple independent plunger groups (first plunger group and second plunger group) that can be selectively activated. This segmentation allows the system to supply oil only to the specific actuators that require operation at any given time, rather than continuously supplying all actuators, thus reducing energy loss while maintaining readiness for required operations
Solution Approach 2:
The system applies partial action by activating only the necessary plunger groups based on operational requirements. For instance, during travel operations, only the first plunger group is activated to supply the travel motor, rather than continuously operating all pump components, thereby avoiding excessive energy consumption while maintaining system responsiveness
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 reduces energy consumption and costs by utilizing electric motors more efficiently, minimizing unnecessary energy use during operations that require less oil, and allowing for precise control of oil supply to different actuators, thereby enhancing operational efficiency.
Implementation Method 1
a hydraulic pump is activated by an electric motor, and operating oil supplied from the hydraulic pump is used to actuate a hydraulic actuator
Data Source
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Figure 3A~3C
AI summary
To provide a hydraulic control device for a construction machine, wherein the amount of drive of an electric motor is reduced in order to minimize cost and conserve energy, and wasteful energy consumption can be minimized. The hydraulic control device for a construction machine comprises a hydraulically actuated primary actuator group and a secondary actuator group which is used less frequently than the primary actuator group. The hydraulic control device also comprises primary pumps (P1, P2) for supplying operating oil to the primary actuator group; secondary pumps (P3, P4) for supplying the operating oil to the secondary actuator group; actuator operating means; a remote control valve group (75) and a pilot valve (72) for outputting pilot pressures according to the operated amount of the actuator operation means; a primary control valve group (50) and a secondary control valve group (60), which are driven by the pilot pressures and which control the flow rate of the operating oil supplied to the hydraulic actuators; a first electric motor (M1) for driving the primary pumps (P1, P2); and a second electric motor (M2) for driving the secondary pumps (P3, P4).