Excavator Control Valve With Variable Return Flow Opening
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Solution Overview
Problem
Existing excavators experience unnecessary pressure loss when hydraulic oil flows from hydraulic cylinders to hydraulic oil tanks, particularly during high-load operations like excavation, due to the presence of diaphragms in the flow path.
Innovation Solution
The excavator incorporates a control device that dynamically adjusts the opening area of the flow path between the hydraulic actuator and the hydraulic oil tank using a solenoid valve, increasing the opening area during high-load operations to reduce pressure loss and prevent wasteful energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If diaphragms are installed in the flow path between hydraulic cylinder and hydraulic oil tank, then the operating speed of hydraulic cylinder can be suppressed, but unnecessary pressure loss occurs during high-load operations
Solution Approach 1:
The patent applies dynamics by making the flow path opening area variable rather than fixed. The second control valve dynamically adjusts the opening area of the flow path between the hydraulic actuator and hydraulic oil tank based on operating conditions. During high-load operations, the opening area is increased to reduce pressure loss, while during normal operations, it maintains the suppressed speed function. This dynamic adjustment resolves the contradiction between maintaining speed suppression and reducing energy loss.
2Loss of energy
If the opening area of flow path is increased during high-load operations, then pressure loss is reduced, but the ability to suppress operating speed may be compromised
Solution Approach 1:
The system dynamically adjusts the flow path opening area based on real-time operating conditions detected by sensors. During high-load operations, the opening area is increased to minimize pressure loss and energy waste. During normal operations, the opening area is maintained at a level that provides speed suppression. This conditional dynamic adjustment ensures that speed control is maintained when needed while reducing energy loss when load demands are high.
3Object-affected harmful factors
If a switching valve with multiple diaphragms is used, then fluid noise can be reduced, but device complexity increases
Solution Approach 1:
The patent extracts the noise-reduction function from a complex multi-diaphragm switching valve configuration and implements it through a simplified control valve system. The second control valve with adjustable opening area achieves both noise reduction and pressure loss reduction without requiring multiple diaphragms in series or complex switching mechanisms. This extraction of the essential function simplifies the overall device structure while maintaining the beneficial effects.
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 solution effectively reduces pressure loss and conserves energy by optimizing the flow rate of hydraulic oil during high-load tasks, enhancing the operational efficiency of the excavator.
Implementation Method 1
increasing the opening area during high-load operations to reduce pressure loss and prevent wasteful energy consumption
Data Source
AI summary
An excavator includes a lower travelling body; an upper turning body mounted on the lower travelling body; an engine installed in the upper turning body; a hydraulic pump connected to the engine; a hydraulic actuator driven by hydraulic oil discharged by the hydraulic pump to move a work element; a first control valve configured to control a flow rate of the hydraulic oil flowing from the hydraulic pump to the hydraulic actuator; a second control valve configured to control a flow rate of the hydraulic oil flowing from the hydraulic actuator to a hydraulic oil tank; and a control device configured to control opening and closing of the second control valve.