Pilot Hydraulic Valve Control for Multi-Function Working Machines
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Solution Overview
Problem
The existing hydraulic systems for working machines, such as skid-steer loaders and backhoes, have operation devices that are limited to controlling only control valves and are unable to change operation patterns, making them unusable for operating other valves like switching and proportional valves.
Innovation Solution
A hydraulic system that includes an operation device capable of changing operation patterns, featuring a hydraulic pump, pilot fluid passage, first and second control valves, a proportional valve, pressure detector, and a controller that adjusts the proportional valve based on detected pressure to control the flow of hydraulic fluid to hydraulic actuators, including a blocking switching valve and solenoid switching valve to manage pilot fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated hydraulic circuit with operation device is used to control control valves, then the control valves can be operated reliably, but the operation device becomes unusable for operating other valves such as switching valves and proportional valves
Solution Approach 1:
The operation device is designed to serve multiple functions: it can operate both control valves through the pilot fluid passage and switching valves/proportional valves through the hydraulic fluid passage. The system allows the single operation device to control different valve types by routing hydraulic fluid through different passages based on operational needs.
Solution Approach 2:
The hydraulic system is divided into separate functional passages: a pilot fluid passage for controlling control valves and a hydraulic fluid passage for operating switching valves and proportional valves. This segmentation allows each passage to be optimized for its specific function while enabling the operation device to control both types of valves.
2Device complexity
If the operation device has a single operation pattern for controlling control valves, then the control system is simple, but it cannot operate other valves like switching and proportional valves
Solution Approach 1:
The operation device is designed with multi-functionality to operate different types of valves (control valves, switching valves, and proportional valves) through different hydraulic passages, expanding its capability without requiring multiple separate operation devices.
Solution Approach 2:
The system dynamically switches between different operation modes by routing hydraulic fluid through different passages. The operation device can adapt its function based on which passage is active, allowing it to control different valve types as needed.
3Adaptability or versatility
If multiple separate operation devices are used to control different valve types, then each valve can be operated independently, but the system complexity and number of components increase
Solution Approach 1:
Multiple operation functions are merged into a single operation device. The system combines the control of control valves, switching valves, and proportional valves through one operation device by using separate hydraulic passages that can be selectively activated.
Solution Approach 2:
A single operation device is designed to perform multiple valve control functions, eliminating the need for separate operation devices for each valve type while maintaining independent control capability through passage selection.
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 the operation of multiple valve types, including switching and proportional valves, using a single operation device, enhancing the flexibility and functionality of the hydraulic system for working machines.
Implementation Method 1
a pressure detector provided in the pilot fluid passage to detect a pressure in the pilot fluid passage
Implementation Method 2
a hydraulic pump to output a hydraulic fluid, an operation device operable to supply a pilot fluid
Implementation Method 3
a proportional valve to change, in order to operate the second control valve, a pressure of the pilot fluid to be supplied to the second control valve
Data Source
AI summary
A hydraulic system for a working machine includes a hydraulic pump to output a hydraulic fluid, an operation device operable to supply a pilot fluid in accordance with an amount by which the operation device is operated, a hydraulic actuator to be operated by the hydraulic fluid, a pilot fluid passage connected to the operation device, a first control valve connected to the pilot fluid passage and to be operated by the pilot fluid to control a flow of the hydraulic fluid, a second control valve to be operated by the pilot fluid to control a flow of the hydraulic fluid, a proportional valve to change a pressure of the pilot fluid to operate the second control valve, a pressure detector provided in the pilot fluid passage to detect a pressure in the pilot fluid passage, and a controller to control the proportional valve based on the pressure.