Pilot-Operated Control Valve Layout for Compact Floating Function
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Solution Overview
Problem
The existing control valve units with a floating function are oversized due to the increased spool length of the control valve, which is problematic for applications like tractors equipped with front loaders.
Innovation Solution
A control valve unit configuration that includes a pilot-operated control valve with three positions, additional pilot-operated operation valves, and check or on-off valves to achieve a floating function while maintaining a compact size, utilizing a neutral position to connect oil passages to the tank, reducing leakage, and using two-position switching type valves for cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a control valve with four positions is used to achieve floating function, then the floating operation is enabled, but the spool length increases and the control valve unit size increases
Solution Approach 1:
The patent divides the control valve system into two separate two-position valves instead of using one four-position valve. Each two-position valve controls one oil passage (first oil passage and second oil passage respectively), allowing the floating function to be achieved without requiring a long spool. The segmentation of control functions into separate valves reduces the spool length requirement while maintaining the ability to connect both oil passages to the tank simultaneously for floating operation.
2Adaptability or versatility
If a control valve with four positions is used to achieve floating function, then the floating operation is enabled, but the control valve unit size increases
Solution Approach 1:
The control valve unit is segmented into two independent two-position valves, each managing a specific oil passage. This segmentation allows for a more compact arrangement compared to a single four-position valve, as each valve can be optimized independently and arranged in series or parallel configurations that minimize the overall footprint of the control unit.
Solution Approach 2:
Each two-position valve is designed to perform multiple functions: normal operation (connecting pump to actuator) and floating operation (connecting actuator to tank). This multi-functionality eliminates the need for additional dedicated floating valves, reducing the overall number of components and the size of the control valve unit while maintaining full operational capability.
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 configuration allows for a compact control valve unit with a floating function, reducing size and leakage, and achieving the floating operation with a simpler and cost-effective design.
Implementation Method 1
a first pilot valve configured to be operated to a first supply position at which pilot hydraulic oil is supplied to a port in the control valve configured to operate the control valve to the first position
Data Source
AI summary
A control valve unit includes a pilot-operated first operation valve 21 that can be operated to a first closed position at which a first oil passage 41 and a tank port 24 are disconnected from each other and a first open position at which the first oil passage 41 and the tank port 24 are connected to each other; and a pilot-operated second operation valve 22 that can be operated to a second closed position at which a second oil passage 42 and the tank port 24 are disconnected from each other and a second open position at which the second oil passage 42 and the tank port 24 are connected to each other.