Anti-Reverse Spool Valve Without Check Valves for Hydraulic Motors
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Solution Overview
Problem
Existing anti-reverse valves for hydraulic motors in excavators are costly due to complex configurations and a large number of parts, particularly the use of check valves, which complicates the prevention of reverse actions after the motor stops.
Innovation Solution
An anti-reverse valve design featuring a spool movable between various positions to manage pressure and prevent reverse action by releasing pressure to a tank, eliminating the need for check valves and simplifying the configuration, thus reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pair of check valves is provided inside a spool to prevent reverse action, then the reverse action of hydraulic motor is prevented, but the number of parts increases and configuration becomes complicated
Solution Approach 1:
The invention extracts and eliminates the check valves from the spool assembly, replacing them with a simplified spool-based pressure control mechanism. The spool directly controls communication between the discharge side oil passage and suction side oil passage without requiring separate check valve components, thereby maintaining reverse action prevention while reducing part count and configuration complexity.
Solution Approach 2:
The spool is designed to perform multiple functions: it controls oil passage communication, regulates pressure differential, and prevents reverse action all through a single component. This multi-functional design eliminates the need for separate check valves and other auxiliary components, simplifying the overall valve configuration while maintaining effective reverse action prevention.
2Reliability
If a pair of check valves is provided inside a spool to prevent reverse action, then the reverse action of hydraulic motor is prevented, but the cost increases
Solution Approach 1:
The invention merges the functions of multiple components (check valves, spool, and pressure control elements) into a single integrated spool assembly. This consolidation reduces the total number of parts that need to be manufactured, assembled, and maintained, thereby lowering manufacturing costs while effectively preventing hydraulic motor reverse action through the unified pressure control mechanism.
3Speed
If high pressure remains in the discharge side oil passage to generate brake pressure, then the hydraulic motor stops by brake pressure, but this pressure causes reverse action of the hydraulic motor
Solution Approach 1:
The spool is designed to dynamically respond to pressure differential between discharge and suction sides. When reverse action begins, the pressure differential automatically moves the spool to open communication between oil passages, equalizing pressure and stopping reverse rotation. This dynamic response mechanism effectively prevents reverse action while allowing normal braking function.
Solution Approach 2:
The valve incorporates a feedback mechanism where the pressure differential between discharge and suction sides automatically controls spool position. When reverse pressure builds up, it feeds back to move the spool, which then opens oil passage communication to equalize pressures and eliminate reverse action, creating a self-regulating system that maintains reliability without external control.
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 prevents reverse actions of hydraulic motors at a lower cost by simplifying the valve design and eliminating the need for check valves, while also preventing excessive pressure from damaging sealing components.
Implementation Method 1
when a second communication position at which the second supply and discharge passage and the drain passage communicate with each other is established, the reverse pressure is released to the tank (19)
Data Source
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AI summary
In an anti-reverse valve (100), a first communication passage (151) that allows the first supply and discharge passage (111) to communicate with the first pressure chamber (121) and a second communication passage (152) that allows the second supply and discharge passage (112) to communicate with the second pressure chamber (122) are provided inside the spool (102), a first restrictor (151c) is provided in the first communication passage (151), a second restrictor (152c) is provided in the second communication passage (152), and a first annular groove (141) that allows the first supply and discharge passage (111) to communicate with the drain passage (113) when the spool (102) is placed at the first communication position (C1) and a second annular groove (142) that allows the second supply and discharge passage (112) to communicate with the drain passage (114) when the spool (102) is placed at the second communication position (C2) are provided in an outer periphery of the spool (102).