Pilot Pressure Check Valve Structure for Faster Spool Response
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Solution Overview
Problem
The responsiveness of check valves is deteriorated due to pressure retention in the spacer portion when the pilot pressure transitions from the first pilot chamber to the second pilot chamber, causing delayed valve opening operations.
Innovation Solution
A movement regulating portion, comprising a projecting portion on the spacer and a taper on the spool, regulates the spacer's movement, preventing pressure retention and ensuring immediate valve opening when the pilot pressure is applied to the second pilot chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base end portion of the rod is screwed and fastened to the one end portion of the spool, then the check valve can be assembled and function properly, but pressure retention occurs in the space between the spacer portion and the rod end surface, causing delayed valve opening operation
Solution Approach 1:
The patent extracts the harmful pressure retention from the system by introducing a communication passage that connects the space between the spacer portion and rod end surface to the first pilot chamber. This allows the trapped pressure to be discharged, eliminating the delay in valve opening operation while maintaining the screwed connection structure for reliable check valve assembly.
Solution Approach 2:
The communication passage acts as an intermediary channel between the trapped pressure space and the first pilot chamber. It provides a controlled pathway for pressure equalization, allowing the harmful pressure retention to be converted into a useful pressure communication mechanism that improves valve response time without compromising assembly reliability.
2Stress or pressure
If working oil enters through the connection portion between the spool and rod, then pressure builds up in the space behind the spacer portion, but this pressure retention inhibits valve opening operation and deteriorates responsiveness
Solution Approach 1:
The patent removes the harmful effect of pressure buildup by providing a discharge pathway through the communication passage. This passage extracts the excess pressure from the space behind the spacer portion and redirects it to the first pilot chamber, preventing pressure retention that would otherwise inhibit valve opening and reduce responsiveness.
Solution Approach 2:
The patent converts the harmful pressure buildup into a beneficial pressure communication mechanism. By routing the pressure through the communication passage to the first pilot chamber, the previously harmful pressure retention is transformed into a controlled pressure transfer that actually aids in the valve opening operation and improves overall system responsiveness.
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 configuration enhances the responsiveness of the check valve by preventing pressure retention and ensuring timely valve opening, thereby improving the control valve's operational efficiency.
Implementation Method 1
a check valve configured to allow only flow from the second pilot chamber to the signal pressure passage
Implementation Method 2
A centering spring configured to apply a spring force to one end portion of the spool
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A control valve (100) has a first and second pilot chambers (14, 15) facing both ends of a spool (12), a signal pressure passage (18) configured to lead a pilot pressure of the first and second pilot chambers (14, 15) to another device other than the control valve (100) as a signal pressure, a communication groove (19) configured to allow the first pilot chamber (14) and the signal pressure passage (18) to communicate with each other, a communication hole (20) configured to allow the second pilot chamber (15) and the signal pressure passage (18) to communicate with each other, and a check valve (21) interposed in the communication hole (20), and the check valve (21) has a poppet portion (50) configured to open or close the communication hole (20) and a spacer portion (60) configured to regulate a moving amount of the poppet portion (50) in an open direction, and the control valve (100) further includes a movement regulating portion (80) configured to regulate movement of the spacer portion (60) toward the poppet portion (50).