Hydraulic Flow-Path Switching for Accurate Regeneration Control
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Solution Overview
Problem
Conventional hydraulic control apparatuses for work machines face challenges in determining appropriate regeneration operations during combined operation states due to communication between pump lines affecting pump pressure, making it difficult to assess the need for regeneration based on pump pressure alone.
Innovation Solution
A hydraulic control apparatus with a flow-path selector valve, regeneration valve, and regeneration release valve, along with a pump pressure detector and driving state detector, allows for appropriate flow path formation and regeneration operation judgment in both single and combined operation states by shifting the flow-path selector valve and controlling the regeneration valves based on detected pressures and driving states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a communication flow path is provided between pump lines in combined operation state, then the sudden decrease in traveling speed is reduced, but the pump pressure becomes affected by traveling motor drive pressure making regeneration operation judgment difficult
Solution Approach 1:
The hydraulic system is segmented into two independent pump lines (first pump line and second pump line) that operate separately. The flow path selector valve can switch between connecting to the first pump line or the second pump line, allowing independent pressure measurement for regeneration judgment without interference from traveling motor operations.
Solution Approach 2:
The flow path selector valve acts as an intermediary that selectively connects the hydraulic actuators to either the first pump line or the second pump line. This mediation allows the system to isolate pressure measurements to a single pump line, eliminating the confounding effect of communication between pump lines on pressure measurement accuracy.
2Adaptability or versatility
If flow path switching is performed in combined operation state, then work actuator operation is enabled, but the flow rate to traveling motors is suddenly decreased by half
Solution Approach 1:
The communication flow path is established in advance before flow path switching occurs. This preliminary action ensures that when the flow path selector valve switches from the neutral position to the work position, the traveling motors already have an alternative supply path available, preventing sudden flow rate decrease and maintaining traveling speed.
Solution Approach 2:
The communication flow path maintains continuous hydraulic fluid supply to the traveling motors during flow path switching. By providing a parallel supply path, the system ensures uninterrupted flow to the traveling motors, maintaining the continuity of useful action (traveling motion) while enabling work actuator operation.
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 accurate determination of regeneration operations in both single and combined states, ensuring efficient hydraulic fluid management and improved work machine performance by accounting for load variations and pump pressures.
Implementation Method 1
a first pump that discharges hydraulic fluid; a second pump that is separately provided from the first pump and discharges hydraulic fluid
Implementation Method 2
a flow-path selector valve capable of making a flow-path switching motion for switching a flow path of hydraulic fluid discharged by the first pump and the second pump
Implementation Method 3
a regeneration valve provided in a regeneration flow path for merging discharge hydraulic fluid that is discharged from the work actuator making the work actuator perform the target work motion into supply hydraulic fluid that is to be supplied to the work actuator
Implementation Method 4
a pump pressure detector that detects a second pump pressure, which is a pressure of hydraulic fluid discharged by the second pump
Implementation Method 5
a driving state detector that detects a physical quantity which is an index of a driving state of the work actuator and varied with a variation in the load of the work actuator
Data Source
AI summary
Disclosed is a hydraulic control apparatus including a flow-path selector valve that switches a supply flow path and a flow-path switching control unit that operates the same, a regeneration valve and a regeneration release valve capable of the regenerative operation, and a regeneration control unit that operates the same. The flow-path switching control unit makes the flow-path selector valve form a flow-path providing communication between first and second pumps in a combined operation state. The regeneration control unit judges the propriety of the regenerative operation on the basis of the second pump pressure which is the discharge pressure of the second pump in a single operation state and judges the propriety of the regenerative operation on the basis of whether or not the driving state of the work actuator is within an allowable range corresponding to the target work operation amount in the combined operation state.