Hydraulic Pilot Circuit Switching for Multi-Pattern Valve Control
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Solution Overview
Problem
The existing hydraulic systems for working machines, such as skid-steer loaders and backhoes, are limited by operation devices that can only switch control valves using a single operation pattern, making them unusable for operating other valves like switching valves and proportional valves.
Innovation Solution
The proposed hydraulic system introduces an operation device that can change its operation pattern by using a blocking switching valve and a solenoid valve, allowing the system to operate multiple control valves, including proportional valves, based on detected pilot pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single operation device is used to control hydraulic valves, then the device structure is simple, but the operation device cannot operate multiple types of valves (switching valves and proportional valves) with different operation patterns
Solution Approach 1:
The operation device is designed to perform multiple functions by controlling different types of hydraulic valves through a unified interface. The single operation device can operate both switching valves and proportional valves by selecting different operation patterns, eliminating the need for separate operation devices for each valve type while maintaining structural simplicity.
Solution Approach 2:
The hydraulic circuit incorporates dynamic switching capability through a switching valve that can change its connection state based on operation pattern selection. This allows the system to dynamically reconfigure the hydraulic circuit to match different operation requirements, enabling the same operation device to control different valve types appropriately.
2Ease of operation
If multiple dedicated operation devices are provided for different valves, then each valve can be operated optimally, but the device complexity and number of components increase
Solution Approach 1:
Instead of providing separate operation devices for switching valves and proportional valves, the invention uses a single operation device that can adapt to control different valve types. This reduces the number of operation devices while maintaining optimal control capability through pattern selection and electronic proportioning mechanisms.
Solution Approach 2:
The invention introduces an electronic proportioning mechanism and control system as an intermediary between the operation device and the hydraulic valves. This intermediary translates the operator's input into appropriate control signals for different valve types, enabling a single operation device to effectively control multiple valve types with different operation characteristics.
3Adaptability or versatility
If the operation device has a fixed operation pattern, then the hydraulic circuit is simple, but the device cannot be used for operating other valves like switching valves and proportional valves
Solution Approach 1:
The operation device incorporates dynamic pattern switching capability that allows it to adapt its operation mode based on the type of valve being controlled. An operation pattern selection mechanism enables the device to switch between different control patterns, making it compatible with both switching valves and proportional valves without requiring multiple dedicated devices.
Solution Approach 2:
The invention changes the operational parameters of the operation device based on the selected operation pattern. By adjusting parameters such as control pressure, flow rate, and response characteristics according to the pattern selection, the same operation device can effectively control different types of hydraulic valves with varying operational requirements.
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
This solution enables the hydraulic system to dynamically change its operation pattern, allowing the operation device to control various hydraulic actuators and valves, enhancing the versatility and operational capabilities of the working machine.
Implementation Method 1
a blocking switching valve provided in the first pilot fluid passage
Implementation Method 2
a solenoid valve provided in the second pilot fluid passage
Implementation Method 3
a pressure detector to detect a pilot pressure which is a pressure of the pilot fluid in the first pilot fluid passage
Implementation Method 4
the hydraulic-pilot-operated hydraulic system includes a dedicated hydraulic circuit to control the flow of a pilot fluid for operating the control valves
Data Source
AI summary
In a working machine, a controller is configured or programmed to control actuation of a blocking switching valve and a solenoid valve, to cause the blocking switching valve to unblock a first pilot fluid passage to perform switching to a first operation pattern in which an operation device operates a first device via a first control valve and a first hydraulic actuator, and cause the blocking switching valve to block a second pilot fluid passage and control the solenoid valve based on pilot pressure detected by a pressure detector to perform switching to a second operation pattern in which the operation device operates a second device via a second control valve and a second hydraulic actuator.