Priority Valve Hydraulic Circuit for Concurrent Actuator Flow
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Solution Overview
Problem
The existing single-pump hydraulic systems in construction machines face challenges with insufficient flow rates when both travel and work equipment operations are performed concurrently, leading to decreased speeds due to complex hardware and software configurations and high costs.
Innovation Solution
A hydraulic circuit with a priority valve that fully opens or restricts the second pump line based on the pressure difference between the pump delivery pressure and the load pressure of the first actuator, ensuring a secure flow rate for the first actuator and preventing speed decreases, without requiring multiple valves or complex control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple pressure compensation valves and solenoid valves are used to control flow rates to multiple actuators, then the moving speed of actuators can be maintained during concurrent operations, but the system complexity and cost increase
Solution Approach 1:
The patent combines the functions of multiple pressure compensation valves and solenoid valves into a single priority valve that automatically prioritizes flow distribution. This single valve integrates the control functions that would otherwise require multiple separate components, thereby maintaining actuator speeds during concurrent operations while significantly reducing system complexity
Solution Approach 2:
The priority valve operates autonomously based on pressure differential signals from the actuators, automatically determining which actuator receives priority flow without requiring external solenoid valve control or complex software routines. This self-service mechanism eliminates the need for multiple controlled valves while maintaining proper flow distribution
2Speed
If multiple pressure compensation valves and solenoid valves are installed to manage concurrent actuator operations, then actuator speed maintenance is achieved, but the hardware configuration becomes complex and costly
Solution Approach 1:
The patent merges multiple valve functions into a single priority valve component, reducing the total number of parts that need to be manufactured and assembled. This consolidation directly lowers hardware costs and simplifies manufacturing processes while maintaining the capability to preserve actuator speeds during simultaneous operations
Solution Approach 2:
The priority valve provides a simpler, more cost-effective alternative to multiple expensive solenoid valves and pressure compensation valves. By using a single mechanical valve instead of multiple electronically-controlled valves, the system achieves the same functional outcome at lower hardware cost
3Device complexity
If a single pump is used to supply pressurized oil to both travel and work equipment actuators, then system simplicity is maintained, but flow rate becomes insufficient during concurrent operations
Solution Approach 1:
The priority valve acts as an intermediary device between the single pump and the multiple actuators. It automatically distributes the limited pump flow rate by prioritizing the actuator with higher load pressure, ensuring that the single pump can effectively serve multiple actuators during concurrent operations without requiring additional pumps or complex valve assemblies
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 simplifies the system, maintaining high moving speeds for both actuators during concurrent operations by prioritizing the flow rate to the first actuator, reducing the need for complex hardware and software configurations and lowering costs.
Implementation Method 1
a priority valve provided on the second pump line. The priority valve is configured to: fully open the second pump line when a pressure difference between a delivery pressure of the pump and a load pressure of the first actuator is greater than a setting value; and decrease an opening degree of the second pump line in accordance with decrease in the pressure difference when the pressure difference is less than the setting value.
Data Source
AI summary
A hydraulic circuit of a construction machine includes: a first pump line that connects a delivery port of a pump to a pump port of a first direction-switching valve; a second pump line that is branched off from the first pump line and is connected to a pump port of a second direction-switching valve; and a priority valve provided on the second pump line. The priority valve is configured to: fully open the second pump line when a pressure difference between a delivery pressure of the pump and a load pressure of a first actuator is greater than a setting value; and decrease an opening degree of the second pump line in accordance with decrease in the pressure difference when the pressure difference is less than the setting value.