Excavator Hydraulic Valve Control for Heavy Digging Load Sharing
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Solution Overview
Problem
The hydraulic system of an excavator may not properly distribute hydraulic oil to its three hydraulic cylinders, depending on the working state of the equipment, leading to inefficiencies in operation.
Innovation Solution
A hydraulic system with two pumps, three cylinders, and a control mechanism that includes operation valves and check valves, along with a work state determination unit and valve control unit, to manage the distribution of hydraulic oil based on the operational state, ensuring proper allocation during normal and heavy excavation states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic oil is distributed to three hydraulic cylinders from two hydraulic pumps without control mechanism, then the system structure is simple, but hydraulic oil cannot be properly distributed to the hydraulic cylinders depending on working state
Solution Approach 1:
The patent applies dynamics by making the hydraulic system's oil distribution paths dynamically controllable through operation valves. The valves can switch between different working states (normal state and heavy excavation state) based on actual working conditions, allowing the system to adapt its oil distribution configuration dynamically rather than being fixed. This resolves the contradiction by enabling reliable oil distribution under varying conditions without requiring a completely complex static control structure.
Solution Approach 2:
The patent changes the operational parameters of the hydraulic system by introducing control valves that can alter the flow paths and pressure distribution. The operation valves change the system state between normal operation and heavy excavation modes, effectively changing parameters like oil flow direction, pressure allocation, and cylinder actuation patterns. This allows reliable hydraulic oil distribution across different working conditions while maintaining a manageable control system complexity.
2Power
If hydraulic oil is supplied to all three hydraulic cylinders from both hydraulic pumps simultaneously, then the power supply is sufficient, but the hydraulic oil cannot be properly distributed depending on working state leading to pressure insufficiency
Solution Approach 1:
The patent applies local quality by directing hydraulic oil from different pumps to different hydraulic cylinders based on the specific working state. In normal state, both pumps can supply oil to all cylinders. In heavy excavation state, the control system allocates oil preferentially to the bucket cylinder (which requires high power for excavation) while maintaining supply to other cylinders. This localized optimization of oil distribution ensures both sufficient power supply and reliable pressure distribution according to actual needs.
Solution Approach 2:
The patent changes the pressure and flow parameters of hydraulic oil distribution based on working state. The operation valves adjust the pressure allocation to different cylinders dynamically - in heavy excavation state, higher pressure is directed to the bucket cylinder while maintaining adequate pressure in other cylinders. This parameter adjustment ensures sufficient hydraulic power where needed while maintaining reliable pressure distribution system-wide.
3Productivity
If the system uses fixed hydraulic oil distribution paths, then the device complexity is low, but the productivity decreases during heavy excavation states due to pressure insufficiency
Solution Approach 1:
The patent makes the hydraulic oil distribution dynamic rather than fixed. The operation valves can switch between normal state and heavy excavation state configurations, allowing the system to optimize oil flow paths based on actual productivity requirements. During heavy excavation, the system dynamically redirects oil flow to prioritize the bucket cylinder, maximizing excavation productivity. This dynamic adaptability achieves high productivity without requiring excessively complex control mechanisms.
Solution Approach 2:
The operation valves are designed with multi-functionality, serving both as flow control elements and as state-switching mechanisms. The same valves that control normal oil distribution also enable the heavy excavation mode by redirecting oil flow. This universal design allows the control system to achieve high productivity in excavation operations without adding separate dedicated control mechanisms, thereby limiting the increase in device complexity.
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
Ensures proper distribution of hydraulic oil to the cylinders, enhancing operational efficiency and preventing pressure insufficiency during heavy excavation states by adjusting the flow of oil from the pumps to the cylinders.
Implementation Method 1
an arm check valve that prevents backflow of hydraulic oil from the arm cylinder to the second hydraulic pump via the second arm operation valve
Implementation Method 2
a bucket check valve that prevents backflow of hydraulic oil from the bucket cylinder to the second hydraulic pump via the second bucket operation valve
Data Source
AI summary
A hydraulic system of an excavator includes a work state determination unit and a valve control unit. When it is determined that a work state of working equipment is a heavy excavation state, the valve control unit controls a first boom operation valve, a first arm operation valve, a first bucket operation valve, a second boom operation valve, a second arm operation valve, and a second bucket operation valve such that passing of hydraulic oil from a first hydraulic pump to a boom cylinder is restricted, hydraulic oil is supplied from a second hydraulic pump to a boom cylinder, hydraulic oil is supplied from both the first hydraulic pump and the second hydraulic pump to an arm cylinder, and hydraulic oil is supplied from one or both of the first hydraulic pump and the second hydraulic pump to a bucket cylinder.