Hydraulic Regeneration Circuit for Actuator Speed and Thrust Control
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Solution Overview
Problem
Existing hydraulic control circuits for work machines like hydraulic excavators face challenges in efficiently performing speed control of actuators and thrust control of actuators that regenerate the flow of return fluid, due to interference between meter-in and meter-out opening controls and the complexity of the circuit, leading to increased costs and reduced operability.
Innovation Solution
A work machine configuration that includes a variable displacement hydraulic pump, directional control valves with a simple configuration formed by identical valve bodies and housings, a regeneration flow path, a regeneration valve, and a regeneration control valve, which allows for independent adjustment of meter-in and meter-out openings to achieve targeted flow rates and thrusts, while reducing costs through a simplified design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single spool valve is used for direction switch control, meter-in opening control, and meter-out opening control, then the circuit structure is simple, but the relation between meter-in side opening area and meter-out side opening area is uniquely determined and cannot be changed according to different work contents, causing interference between meter-in and meter-out opening controls
Solution Approach 1:
The patent divides the control circuit into multiple independent spool valves: a first spool valve for direction switch control, a second spool valve for meter-in opening control, and a third spool valve for meter-out opening control. This segmentation allows each valve to be controlled independently according to different work requirements, eliminating the interference between meter-in and meter-out opening controls while maintaining operational flexibility.
2Adaptability or versatility
If four metering valves are used to form a bridge circuit for separate control of head side and rod side supply and discharge, then meter-in and meter-out opening can be changed according to work contents, but the number of parts increases and circuit complexity increases leading to higher costs
Solution Approach 1:
The patent makes the second and third spool valves (for meter-in and meter-out control) capable of performing multiple functions. These valves can switch between controlling supply flow and discharge flow depending on the work mode (single action or combined action), eliminating the need for separate dedicated valves for each function and reducing the total number of parts while maintaining adaptability.
Solution Approach 2:
The patent merges the functions of multiple specialized valves into fewer multi-functional valves. By combining the meter-in and meter-out control functions into the second and third spool valves that can operate in different modes, the circuit achieves the versatility of four specialized valves with fewer components, reducing system complexity and cost.
3Adaptability or versatility
If an auxiliary valve with variable resistance function is added upstream of the directional control valve, then fluid supply can be adjusted according to work contents, but meter-in and meter-out opening control interference is not resolved
Solution Approach 1:
The patent segments the control functions by providing separate spool valves for direction control, meter-in control, and meter-out control. This segmentation ensures that each control function is handled by a dedicated valve that can be independently adjusted, eliminating the interference problem that persists in systems using auxiliary valves with the single directional control valve approach.
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
Enables efficient speed control of actuators and thrust control of actuators that regenerate the flow of return fluid during combined operations, preventing excessive movement due to inertia and reducing costs through a simpler configuration.
Implementation Method 1
a variable displacement hydraulic pump that sucks and delivers a hydraulic working fluid from the hydraulic working fluid tank
Implementation Method 2
a plurality of directional control valves that control a flow of a hydraulic fluid supplied from the hydraulic pump to the plurality of actuators
Implementation Method 3
a regeneration valve that is provided on the regeneration flow path and causes a return fluid of a particular actuator to merge with the meter-in flow path from the meter-out flow path
Implementation Method 4
a regeneration control valve that is provided downstream of a point of branch from the regeneration flow path on the meter-out flow path and controls a passing flow rate of the regeneration valve by adjusting a flow rate of the hydraulic fluid returned from the particular actuator to the hydraulic working fluid tank
Data Source
AI summary
An object of the present invention is to provide a work machine that makes it possible to perform, with a simple configuration, speed control of respective actuators and thrust control of a particular actuator that regenerates the flow of a return fluid, at the time of combined operation to simultaneously drive the particular actuator and another actuator. For this purpose, a controller calculates a target thrust that is a target value of a thrust of the particular actuator on the basis of an input amount of an operation device and an output value of a posture sensor, calculates a target meter-out pressure that is a target value of a meter-out pressure of the particular actuator on the basis of the target thrust and a meter-in pressure of the particular actuator, and calculates a regeneration control valve target opening area that is a target value of an opening area of a regeneration control valve on the basis of the target meter-out pressure and the meter-out pressure of the particular actuator.