Spool Valve Damping for Hydraulic Collision
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Solution Overview
Problem
Spool valves in hydraulic machines face issues with high-speed collisions with casings, leading to potential damage to components, as existing configurations do not effectively prevent such collisions during state switching.
Innovation Solution
Incorporation of damper chambers and a damper-effect adjustment part, including accumulators, check valves, and variable pressure-reducing valves, to decelerate the spool and adjust the damper effect based on oil viscosity, temperature, and operation pressure, preventing high-speed collisions and enabling adaptive control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the spool valve switches between first state and second state, then the flow channel is switched effectively, but the spool collides with the casing at high speed causing component damage
Solution Approach 1:
The patent applies beforehand cushioning by introducing a damper chamber between the spool and the casing. This damper chamber is pre-filled with oil that acts as a cushioning medium. When the spool moves toward the stroke end, the oil in the damper chamber compresses and provides damping force, preventing high-speed collision before it occurs. This resolves the contradiction by maintaining fast switching while protecting components through advance cushioning preparation.
Solution Approach 2:
The patent employs hydraulics by using oil-filled damper chambers to control spool motion. The hydraulic damping force is generated by the oil's resistance to flow through restricted passages during spool movement. This hydraulic mechanism enables controlled deceleration of the spool, achieving both rapid switching and collision prevention by utilizing the compressibility and flow resistance characteristics of hydraulic fluid.
2Device complexity
If the damper effect is fixed, then the structure is simple, but the deceleration effect is insufficient when oil temperature increases and viscosity decreases
Solution Approach 1:
The patent applies dynamics by making the damper effect adjustable rather than fixed. The damper chamber's damping characteristic can be dynamically changed by controlling the amount of oil injected into it. When oil temperature increases and viscosity decreases, more oil can be injected into the damper chamber to maintain adequate damping force. This dynamic adjustment capability resolves the contradiction between structural simplicity and deceleration effectiveness under varying operating conditions.
Solution Approach 2:
The patent utilizes parameter changes by varying the oil volume in the damper chamber to adjust damping characteristics. The damping force depends on the oil volume and viscosity parameters. By changing the oil volume parameter in response to temperature changes, the system maintains effective deceleration. This parameter adjustment approach allows the simple damper structure to adapt to varying operating conditions and maintain reliability.
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 spool collisions with casings, reducing the risk of component damage and ensuring reliable operation by decelerating the spool and adjusting the damper effect according to varying conditions, thus enhancing the reliability of hydraulic machines and wind turbine power generating apparatuses.
Implementation Method 1
a pair of damper chambers disposed between respective end surfaces of the spool and respective side plates of the casing which face the end surfaces, and configured to decelerate the spool when the spool reaches a position immediately before a stroke end
Implementation Method 2
the damper-effect adjustment part includes a pair of accumulators provided respectively corresponding to the pair of damper chambers
Data Source
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AI summary
A spool valve (30) is used in a hydraulic machine including a hydraulic chamber (34), a high-pressure oil line (12) and a low-pressure oil line (14). The spool valve (30) includes: a casing (31) which includes a hydraulic-chamber port (35) communicating with the hydraulic chamber (34), a high-pressure port communicating with the high-pressure oil line (12), and a low-pressure port communicating with the low-pressure oil line (14); a spool (60) configured to a switch a state of the hydraulic machine between a first state in which the hydraulic chamber (34) and the high-pressure oil line (12) are in communication and a second state in which the hydraulic chamber (34) and the low-pressure oil line (14) are in communication, by moving in an axial direction of the spool inside the casing (31); and a pair of damper chambers (80, 82) disposed between respective end surfaces (63, 66) of the spool (60) and respective side plates of the casing (31) which face the end surfaces (63, 66), and configured to decelerate the spool (60) when the spool (60) reaches a position immediately before a stroke end.