Excavator Hydraulic Pump Control for Variable Negative Feedback
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Solution Overview
Problem
The existing negative control hydraulic system in shovels has a fixed correspondence between hydraulic pump discharge and control pressure, leading to situations where either excessive or insufficient hydraulic oil is discharged, lacking flexibility in control.
Innovation Solution
A shovel with a control device that adjusts the negative control characteristics based on the operation details of the operating device, using a controller to manage the discharge quantity of the hydraulic pump through a power control and energy-saving control mechanism, allowing for flexible control of the hydraulic pump discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed negative control hydraulic system is used, then the system structure is simple, but the discharge amount of the hydraulic pump cannot be flexibly controlled
Solution Approach 1:
The patent applies dynamics by making the control characteristic variable rather than fixed. The control device changes the control characteristic of the negative control based on operation details detected from the operating device, allowing the system to adapt dynamically to different operating conditions. This enables flexible control of the hydraulic pump discharge amount while maintaining system simplicity through automated adaptation.
Solution Approach 2:
The patent changes the control parameter (control characteristic) of the negative control system based on detected operation details. By varying the control characteristic according to the degree of operation, the system achieves flexible discharge amount control without requiring a completely complex control architecture, thus resolving the contradiction between adaptability and device complexity.
2Reliability
If the hydraulic pump discharge is increased to ensure sufficient oil supply, then the actuator operation is reliable, but unnecessary energy is consumed when actuators are not operated
Solution Approach 1:
The patent changes the control characteristic parameter based on operation details to optimize the balance between reliability and energy efficiency. When actuators are operated, the control characteristic ensures sufficient discharge for reliable operation. When not operated, the discharge is reduced to minimize energy consumption, thus resolving the contradiction between reliability and energy loss.
Solution Approach 2:
The patent applies local quality by adjusting the control characteristic according to specific operation conditions rather than maintaining a uniform discharge level. This allows the system to provide high discharge (ensuring reliability) only when needed during actuator operation, and reduce discharge (reducing energy loss) during idle periods, thereby resolving the contradiction locally based on actual operational requirements.
3Loss of energy
If the hydraulic pump discharge is reduced to save energy, then energy consumption decreases, but insufficient oil may be discharged when actuators need operation
Solution Approach 1:
The patent dynamically changes the control characteristic based on detected operation details to prevent insufficient discharge. When operation is detected, the control characteristic is adjusted to ensure adequate discharge for reliable actuator operation. When no operation is detected, the discharge is reduced to save energy, thus resolving the contradiction between energy loss and reliability.
Solution Approach 2:
The patent uses preliminary action by detecting operation details in advance and proactively adjusting the control characteristic before potential insufficient discharge occurs. This ensures that when actuators need operation, the hydraulic pump is already configured to discharge sufficient oil, maintaining reliability while minimizing energy consumption during idle periods.
Data Source
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AI summary
A shovel (100) includes a lower traveling structure (1), an upper swing structure (3) mounted on the lower traveling structure (1), an engine (11) mounted on the upper swing structure (3), a main pump (14) configured to be driven by the engine (11), an attachment attached to the upper swing structure (3), an operating device (26) configured to operate the attachment, and a controller (30) configured to control the discharge quantity of the main pump (14) through negative control. The controller (30) is configured to change a control characteristic of the negative control according to the details of an operation on the operating device (26).