Pilot Check Valve Structure for Residual Pressure Retention
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Solution Overview
Problem
Existing pilot check valves with residual pressure exhaust units face issues where a failure in sealing properties can lead to the unintended exhaustion of pressure fluid from fluid pressure devices during emergencies, such as power supply stoppages, resulting in loss of check function.
Innovation Solution
A pilot check valve design featuring a seal portion in the residual pressure exhaust path and an operation unit that allows selective movement of the check valve element and seal portion to maintain pressure fluid containment, even in case of sealing failures, by allowing fluid flow from the main path to the exhaust hole when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the residual pressure exhaust path is connected to the main path downstream of the check valve element, then the residual pressure can be exhausted from the fluid pressure device, but if a sealing failure occurs in the residual pressure exhaust unit, the pressure fluid may be unintentionally exhausted to the outside, losing the check function
Solution Approach 1:
The invention divides the residual pressure exhaust path into two separate connection points: one upstream of the check valve element and one downstream. This segmentation ensures that even if sealing fails in one path, the check valve element can still prevent unintended exhaustion through the other path, thereby maintaining check function reliability while enabling residual pressure exhaustion.
2Reliability
If a seal portion is added to block flow in the residual pressure exhaust path, then pressure fluid containment is improved, but the device complexity increases
Solution Approach 1:
The check valve element itself serves a dual function: it prevents unintended pressure fluid exhaustion through the residual pressure exhaust path while also allowing controlled residual pressure exhaustion when needed. This self-service approach eliminates the need for separate sealing mechanisms, maintaining pressure fluid containment without significantly increasing device complexity.
3Ease of operation
If the residual pressure exhaust path is provided, then residual pressure can be discharged when the fluid pressure device stops, but the risk of unintended exhaustion during emergencies increases
Solution Approach 1:
By segmenting the residual pressure exhaust path into upstream and downstream connections relative to the check valve element, the invention enables residual pressure discharge capability while maintaining emergency sealing reliability. The check valve element acts as a safeguard that prevents unintended exhaustion even when the residual pressure exhaust path is active.
Solution Approach 2:
The check valve element is positioned to provide beforehand cushioning against unintended pressure fluid exhaustion through the residual pressure exhaust path. This protective measure is built into the structure, ensuring that even if sealing fails or emergencies occur, the check function prevents harmful exhaustion before it can happen.
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 design effectively holds pressure fluid sealed downstream of the check valve element during emergencies, ensuring the check function is maintained even if sealing failures occur, thereby preventing unintended fluid exhaustion.
Implementation Method 1
a check valve element that is provided in the main path, allows a flow of a pressure fluid from a first side in communication with the input port toward a second side in communication with the output port, the check valve element being selectively moved, by supply or discharge of a pilot fluid, to a position where a flow from the output port toward the input port is blocked and a position where the flow is allowed
Implementation Method 2
a seal portion that is provided in the residual pressure exhaust path and blocks a flow of a pressure fluid from the connecting portion of the main path toward a side of the exhaust hole
Implementation Method 3
an operation unit that is capable of moving the check valve element to a position where a flow of a pressure fluid from the second side toward the first side in the main path is allowed and moving the seal portion to a position where the flow of a pressure fluid from the connecting portion of the main path in the residual pressure exhaust path toward the exhaust hole is allowed
Data Source
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AI summary
[Object] To provide a pilot check valve capable of holding residual pressure in a fluid pressure device when a failure occurs in a residual pressure exhaust unit. [Solution] A pilot check valve 10 includes a first body 18 that has input and output ports 11 and 12, a main path 13 that is in communication these ports, and a check valve element 14 that is provided in the main path and allows a flow of a pressure fluid from the input port toward the output port. The valve element blocks or allows a flow from the output port toward the input port side by supply or discharge of a pilot fluid. The check valve has a residual pressure exhaust path 15 having one end connected to a central hole 37 of the main path and another end connected to an exhaust hole 56, a seal member 48 that is provided in the exhaust path, and a push rod 45 that moves the check valve element to a position where a flow of a pressure fluid from the output port side toward the input port side in the main path is allowed and moves the seal portion to a position where a flow from the connecting portion toward the exhaust hole is allowed.