Hydraulic Flow-Path Switching for Stable Travel and Work Pressure
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Solution Overview
Problem
Conventional hydraulic control apparatuses experience a sudden drop in traveling speed when shifting from a single operation state to a combined operation state, and fail to secure necessary driving pressure for the work actuator while preventing excessive increase in traveling speed.
Innovation Solution
A hydraulic control apparatus with a flow-path selector valve and a flow-path switching control unit that adjusts the communication flow path's opening area based on the detected driving state of the work actuator, ensuring the necessary driving pressure is maintained and traveling speed is not excessively increased during combined operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the communication flow path is opened when working pressure is higher than traveling pressure, then the sudden deceleration of traveling motion is prevented, but the traveling speed excessively increases and the working pressure of work actuator cannot be secured
Solution Approach 1:
The invention changes the opening area parameter of the communication flow path from fixed to variable. The flow-path switching control unit adjusts the opening area based on the detected driving state of the work actuator, allowing the system to optimize both traveling speed and working pressure dynamically rather than using a fixed opening that causes contradictory effects
Solution Approach 2:
The invention introduces feedback control by using the driving state detector to monitor the work actuator's performance and feed this information back to the flow-path switching control unit. This closed-loop control enables real-time adjustment of the communication flow path opening area to maintain optimal balance between traveling speed and working pressure
2Speed
If the communication flow path provides communication between pump lines, then the flow rate to traveling motors is maintained during valve switching, but hydraulic fluid that should supply the work actuator flows into the traveling motor at large flow rate
Solution Approach 1:
The invention dynamically changes the opening area parameter of the communication flow path based on system conditions. By adjusting this parameter, the system can control the flow rate distribution between work actuator and traveling motor, preventing excessive flow to the traveling motor while maintaining speed stability during valve transitions
Solution Approach 2:
The invention transforms the static communication flow path into a dynamic one with variable opening area. This allows the system to adapt the flow distribution in real-time according to the driving state, ensuring that hydraulic fluid is properly directed to maintain both traveling speed stability and work actuator performance
3Stability of the object's composition
If the flow-path selector valve is switched to straight traveling position, then the straight traveling ability is secured, but the traveling speed suddenly decreases
Solution Approach 1:
The invention applies preliminary action by opening the communication flow path before or during the valve switching process. This preparatory action ensures that hydraulic fluid can be supplied to traveling motors from both pump lines, maintaining traveling speed stability when the flow-path selector valve switches to the straight traveling position
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
The solution effectively reduces sudden deceleration of traveling speed and secures the driving pressure of the work actuator, preventing excessive increase in traveling speed, thereby ensuring stable operation of the work machine.
Implementation Method 1
the straight traveling position is provided with a communication flow path. The communication flow path provides communication between a pump line connected to the first pump and a pump line connected to the second pump
Implementation Method 2
a first pump that discharges hydraulic fluid; a second pump that is separately provided from the first pump and discharges hydraulic fluid
Implementation Method 3
a work actuator that is driven by supply of hydraulic fluid to make the work attachment perform a target work motion
Implementation Method 4
a first traveling motor that is driven by supply of hydraulic fluid to make the first traveling body perform the traveling motion; a second traveling motor that is driven by supply of hydraulic fluid to make the second traveling body perform the traveling motion
Data Source
AI summary
A hydraulic drive apparatus includes a flow-path selector valve and a flow-path switching control unit that operates the valve. The flow-path selector valve has a first position for a single operation state and a second position for a combined operation state, configured to, at the first position, form a first flow path connected to a first pump, a second flow path connected to a second pump, and a connecting flow path providing communication between the first flow path and the second flow path. When a driving state of a work actuator is deviated from an allowable range in the combined operation state, the flow-path switching control unit reduces an opening area of the connecting flow path as compared with that when the driving state is within the allowable range.