Hydraulic Shut-Off Valve Spool for Pressure Equalization
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Solution Overview
Problem
Hydraulic motors experience pressure spikes and imbalances due to spring-based mechanisms, leading to piston shoe lift and potential damage, which existing case drain lines fail to prevent effectively.
Innovation Solution
A first valve with a spool mechanism that controls hydraulic fluid flow by moving between positions, equalizing pressures across the hydraulic motor system, including the inlet, outlet, and case drain lines, preventing pressure imbalances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a spring-based mechanism is used to keep pistons in contact with the cam plate or swash plate, then the hydraulic motor can be compact, but pressure spikes and pressure imbalances occur causing piston shoe lift and potential damage
Solution Approach 1:
The valve is segmented into multiple independent fluid flow ports (first through fifth ports) that can be independently controlled by the spool mechanism. This segmentation allows selective connection of different hydraulic lines (supply line, control lines, return line, case drain line) to equalize pressures in specific regions without affecting others, thereby preventing piston shoe lift while maintaining compact motor design.
Solution Approach 2:
The valve acts as an intermediary device between the hydraulic motor and the hydraulic lines. By introducing this intermediate component, the system can control and equalize pressures in control lines and case drain lines, preventing direct pressure imbalances from causing piston shoe lift, while the compact hydraulic motor structure is preserved.
2Stress or pressure
If case drain lines are used to relieve excess pressure, then some pressure relief is achieved, but trapped return pressure in motor control lines and increases in case drain pressure upon closing shut-off valves prevent effective prevention of pressure spikes
Solution Approach 1:
The valve is designed to equalize pressures in control lines and case drain lines to the return line pressure before the shut-off valve closes or before pressure spikes occur. This preliminary pressure equalization prevents the trapped return pressure and case drain pressure increases from causing piston shoe lift, rather than merely relieving excess pressure after it occurs.
Solution Approach 2:
The valve merges the control of multiple hydraulic lines (supply line, first control line, second control line, return line, case drain line) into a single integrated mechanism. The spool simultaneously controls connections for all these lines, allowing coordinated pressure equalization across the entire system, preventing the isolated pressure issues that case drain lines alone cannot address.
3Ease of operation
If a traditional shut-off valve is used to stop or start hydraulic fluid flow, then flow control is achieved, but pressure imbalances occur in control lines and case drain lines leading to piston shoe lift
Solution Approach 1:
The valve performs multiple functions simultaneously: it controls hydraulic fluid flow to the hydraulic motor (shut-off function), equalizes pressures in control lines to the return line, and equalizes case drain line pressure to the return line. This multi-functionality is achieved through the spool mechanism that can connect different fluid flow ports in various configurations, providing both flow control and pressure balance without requiring separate valves.
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
Prevents piston shoe lift by equalizing pressures, reducing the likelihood of motor damage and enhancing the reliability of compact hydraulic motors.
Implementation Method 1
a first valve, for controlling the flow of hydraulic fluid therethrough
Implementation Method 2
equalizing pressures across the hydraulic motor system, including the inlet, outlet, and case drain lines
Data Source
Figure 1
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AI summary
A valve (200) for controlling the flow of hydraulic fluid to a hydraulic motor (214) is disclosed. The valve (200) includes a sleeve (209) and a spool (212). The sleeve (209) includes a first fluid flow port (201) for receiving hydraulic fluid from the supply line (223); a second fluid flow port (202) for supplying hydraulic fluid to a second valve (213); a third fluid flow port (203) for receiving hydraulic fluid from a first control line (220a); a fourth fluid flow port (204) for receiving hydraulic fluid from a second control line (220b); and a fifth fluid flow port (205) in fluid communication with the return line (224). The valve (200) is arranged to be actuated to move the spool (212) between a first position and a second position. When the spool (212) is in the second position, the fifth fluid flow port (205) is in fluid communication with the second, third and fourth fluid flow ports (202, 203, 204) and the first fluid flow port (201) is closed by the spool (212).