Hydraulic Pump Flow Allocation for Excavator Actuator Interference
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Solution Overview
Problem
Hydraulic interference and efficiency loss occur when multiple hydraulic actuators in a working machine, such as a hydraulic excavator, are supplied with oil from both pumps, leading to reduced operability and increased circuit complexity.
Innovation Solution
A hydraulic control system that selectively supplies hydraulic oil to actuators from a single pump when operation demands are low and from both pumps when demands are high, adjusting flow rates to ensure each actuator operates at the required speed, minimizing merging frequency and circuit complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hydraulic oil is supplied to hydraulic actuator B from both first and second hydraulic pumps, then the flow rate requirement can be met, but hydraulic interference occurs and efficiency deteriorates
Solution Approach 1:
The hydraulic system is segmented into dedicated supply paths: hydraulic actuator A receives oil only from the first hydraulic pump, while hydraulic actuator B receives oil only from the second hydraulic pump. This segmentation eliminates hydraulic interference between actuators while maintaining the ability to meet high flow rate requirements through the second pump's dedicated supply.
2Speed
If hydraulic oil from both first and second hydraulic pumps is merged and supplied to hydraulic actuator B, then the flow rate requirement can be met, but circuit complexity increases
Solution Approach 1:
The circuit is segmented into separate supply lines: the first hydraulic pump supplies hydraulic actuator A through one path, while the second hydraulic pump supplies hydraulic actuator B through a separate path. This eliminates the need for merging hydraulic oil from both pumps, thereby reducing circuit complexity while still meeting the flow rate requirements of both actuators.
3Device complexity
If the first hydraulic pump supplies both hydraulic actuators A and B, then the circuit is simplified, but the flow rate requirement cannot be met when total demand exceeds pump capacity
Solution Approach 1:
The system is segmented into two independent supply chains: the first hydraulic pump is dedicated to hydraulic actuator A, and the second hydraulic pump is dedicated to hydraulic actuator B. This segmentation allows each pump to independently meet the flow rate requirements of its assigned actuator without being constrained by the other actuator's demand, thereby resolving the flow rate limitation while keeping the circuit relatively simple.
Solution Approach 2:
Each hydraulic pump is designed with multi-functionality to handle different operational scenarios: the first hydraulic pump can supply hydraulic actuator A alone or in combination with the second pump supplying hydraulic actuator B, while the second hydraulic pump can supply hydraulic actuator B alone or in combination with the first pump supplying hydraulic actuator A. This multi-functionality allows the system to meet varying flow rate demands without complex merging mechanisms.
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
Improves operability and efficiency by ensuring each actuator operates at the desired speed, reducing hydraulic interference and circuit complexity, even during simultaneous operations.
Implementation Method 1
a first hydraulic pump, a second hydraulic pump, and a plurality of hydraulic actuators using these first and second hydraulic pumps as hydraulic supply sources
Data Source
AI summary
Problem: In a case where the hydraulic actuator A supplied with hydraulic oil only from the first hydraulic pump and the hydraulic actuator B supplied with hydraulic oil from the first and second hydraulic pumps are operated simultaneously, even if the required flow rate for the first hydraulic pump of the hydraulic actuators A and B exceeds the first hydraulic pump maximum discharge flow rate, the hydraulic actuators A and B can be driven at the operation speed corresponding to the operation amount of the operation means.Solution: A target flow rate correction means is provided for setting the bucket cylinder required flow rate as a target flow rate from the hydraulic pump to the bucket cylinder, a flow rate obtained by subtracting the bucket cylinder required flow rate from the pump maximum discharge flow rate as a target flow rate from the hydraulic pump to the boom cylinder, and setting a flow rate obtained by subtracting the target flow rate from the hydraulic pump to the boom cylinder from the bucket cylinder total required flow rate as a target flow rate from the hydraulic pump to the boom cylinder.