Hydraulic Pressure Circuit With Accumulator-Assisted Smooth Actuation
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Solution Overview
Problem
In hydraulic circuits using fixed displacement pumps, the constant discharge amount can lead to impacts when directional switching valves are switched, and there is a need for a cost-effective solution to smoothly control fluid pressure actuators while effectively utilizing energy.
Innovation Solution
A fluid pressure circuit that includes a tank, a fixed displacement pump, a fluid pressure actuator, a directional switching valve, an accumulator, an accumulator flow control valve, and a pump flow control valve, which is an electromagnetic proportional flow control valve, allowing for variable flow rate control and smooth operation of the fluid pressure actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed displacement pump is used to pressurize fluid, then the pump structure is simple and maintainability is excellent, but the constant discharge amount causes impacts when directional switching valves are switched
Solution Approach 1:
The patent introduces a flow control valve that can dynamically adjust the flow rate of pressurized fluid from the fixed displacement pump. By making the flow rate variable rather than constant, the system can reduce flow during valve switching operations, thereby minimizing impacts while still using a simple fixed displacement pump structure
Solution Approach 2:
The patent changes the parameter of flow rate from constant to variable by introducing a flow control valve. This allows the system to adjust the discharge amount of the fixed displacement pump according to operational needs, reducing impacts during valve switching while maintaining the simplicity of the fixed displacement pump
2Ease of operation
If a variable displacement pump is used to control flow rate smoothly, then the fluid pressure actuator can be smoothly controlled, but the device complexity and cost increase
Solution Approach 1:
The patent separates the flow control function from the pump by introducing a dedicated flow control valve in the circuit. This allows the fixed displacement pump to maintain its simple structure while the flow control valve handles the variable flow rate requirement, achieving smooth control without increasing pump complexity
Solution Approach 2:
The flow control valve acts as an intermediary between the fixed displacement pump and the fluid pressure actuator. It mediates the flow rate adjustment, allowing smooth control of the actuator while the pump itself remains a simple fixed displacement type
3Use of energy by moving object
If return oil is accumulated in an accumulator to utilize energy, then energy use efficiency is high, but the constant discharge from fixed displacement pump causes impacts during directional switching
Solution Approach 1:
The patent introduces a flow control valve that dynamically adjusts the flow rate from the fixed displacement pump, enabling the system to reduce flow during valve switching operations. This resolves the impact issue while maintaining the accumulator for energy recovery from return oil
Solution Approach 2:
By changing the flow rate parameter from constant to variable through the flow control valve, the system can optimize performance during different operational phases - allowing energy recovery in the accumulator during normal operation while minimizing impacts during valve switching events
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 enables smooth control of fluid pressure actuators according to operation commands, effectively utilizes energy by driving the actuator with accumulated fluid, and can be implemented at a low cost due to its simplified structure.
Implementation Method 1
the pump flow control valve is an electromagnetic proportional flow control valve
Implementation Method 2
an accumulator arranged in a branch flow passage branched from a connection flow passage that connects the fluid pressure actuator and the directional switching valve
Data Source
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AI summary
Provide, at a low cost, is a fluid pressure circuit capable of smoothly controlling a fluid pressure actuator according to an operation command and capable of effectively utilizing energy while using a fixed displacement pump. A fluid pressure circuit (130) includes a directional switching valve (4) arranged between a fixed displacement pump (2) and a fluid pressure actuator (5) and configured to switch a flow passage for a pressurized fluid, an accumulator (27) arranged in a branch flow passage (29, 30) branched from a connection flow passage (23) that connects the fluid pressure actuator and the directional switching valve, an accumulator flow control valve (26) arranged between the connection flow passage and the accumulator, and a pump flow control valve (40) arranged between the fluid pressure actuator and the fixed displacement pump and configured to variably divert a flow rate of the pressurized fluid discharged from the fixed displacement pump into a first system including the tank and a second system including the fluid pressure actuator.