Excavator Valve Block Layout for Balanced Hydraulic Flow
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Solution Overview
Problem
The existing excavator systems face challenges in appropriately distributing hydraulic oil to multiple hydraulic actuators during composite operations, as the flow rate of hydraulic oil into the arm cylinder cannot be adequately limited, leading to potential imbalances in oil distribution.
Innovation Solution
The excavator incorporates a first spool valve in the center bypass pipeline and a second spool valve in the parallel pipeline, both formed in a valve block, with the second spool valve disposed upstream of the first spool valve, allowing for precise control of hydraulic oil flow rates to and from hydraulic actuators, including an arm-use second spool valve that adjusts the flow rate to prevent excessive oil flow into actuators with low load pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a poppet type control valve is used to limit hydraulic oil flow rate, then the structure is simple, but the flow rate cannot be appropriately limited during composite operations
Solution Approach 1:
The control valve is divided into two separate spool valves (first spool valve in center bypass pipeline, second spool valve in parallel pipeline) that independently control different flow paths. This segmentation allows precise control of hydraulic oil distribution to multiple actuators during composite operations, resolving the limitation of single-valve poppet type control systems.
2Productivity
If hydraulic oil is supplied to multiple hydraulic actuators through a single pump, then the system is compact and efficient, but the flow rate distribution to each actuator cannot be appropriately controlled during composite operations
Solution Approach 1:
Two spool valves are introduced as intermediary control elements between the single hydraulic pump and multiple actuators. The first spool valve controls flow through the center bypass pipeline, while the second spool valve controls flow through the parallel pipeline. These intermediaries enable precise flow rate distribution to maintain balanced composite operations even with a single pump source.
3Ease of operation
If the flow path area of the center bypass pipeline is reduced when spool valves move from neutral position, then individual actuator control is improved, but the overall hydraulic oil distribution balance deteriorates
Solution Approach 1:
The hydraulic control system is segmented into two independent control paths: center bypass pipeline with first spool valve and parallel pipeline with second spool valve. This segmentation allows each valve to control its respective path without interfering with the other, maintaining overall distribution balance while enabling individual actuator control through coordinated operation of both valves.
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 enables more effective distribution of hydraulic oil to multiple hydraulic actuators during composite operations, preventing unbalanced operations by limiting oil flow into actuators with relatively low load pressures, thus ensuring balanced performance across the excavator's components.
Implementation Method 1
a first spool valve configured to control a flow rate of the hydraulic oil flowing from the hydraulic pump to the hydraulic actuator and a flow rate of the hydraulic oil flowing from the hydraulic actuator to a hydraulic oil tank
Data Source
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AI summary
An excavator according to an embodiment of the present invention includes an arm cylinder (8) driven by hydraulic oil discharged from a main pump (14) to move an arm (5); a control valve (176B) disposed in a center bypass pipeline (42R); a control valve (177) disposed in a parallel pipeline (42R); and a controller (30) for controlling the movement of the control valve (177). The control valve (176B) and the control valve (177) are formed in a valve block (17B) of control valves (17), and the control valve (177) is disposed upstream of the control valve (176B).