Control Valve Damping Device Asymmetric Actuation
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Solution Overview
Problem
Control valves used in hydrostatic drive systems with closed circuits tend to oscillate during pressure changes, leading to leakage from the high-pressure side to the low-pressure side, causing energy losses and potential vehicle instability on slopes.
Innovation Solution
A hydraulic damping device is designed to be active only when the control slide moves from the blocked to the open position, using a damping piston with a throttle device and after-suction opening to dampen the opening movement, while being ineffective during the closing movement, allowing quick actuation to the blocked position and preventing pressure medium leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydraulic damping device is activated during control slide movement, then oscillation is reduced and leakage is prevented, but the control slide movement speed is reduced
Solution Approach 1:
The damping device is designed to be dynamically selective, activating only during the opening stroke of the control slide while remaining inactive during the closing stroke. This is achieved through the asymmetric configuration of the throttle device and after-suction opening, which creates damping pressure differential only when the spool moves from blocked to open position, thus preventing leakage during pressure changes without compromising closing speed
2Stability of the object's composition
If damping is applied in both opening and closing directions, then oscillation is controlled, but the system response time increases
Solution Approach 1:
The damping function is segmented to operate only in one direction (opening stroke) rather than both directions. The throttle device and after-suction opening are positioned and dimensioned to create damping effect exclusively when the control slide opens, allowing the closing operation to proceed rapidly without damping resistance, thus reducing overall system response time while still controlling oscillation during the critical opening phase
3Force
If the damping device uses a throttle device to displace pressure medium, then damping force is generated, but pressure loss increases
Solution Approach 1:
The damping effect is localized to specific phases of operation rather than being continuously applied. The throttle device creates pressure differential and damping force only when the control slide is moving in the opening direction, while the after-suction opening provides a low-resistance path during closing. This localized application of damping quality minimizes overall pressure loss while maintaining sufficient damping force when needed
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 leakage from the high-pressure side to the low-pressure side during pressure changes, reducing energy losses and ensuring vehicle stability by damping only the opening movement of the control slide, allowing rapid and undamped closure to prevent pressure medium escape.
Implementation Method 1
pressure medium is displaced from the damping chamber via a throttle device
Implementation Method 2
pressure medium is used when the damping piston is moved out of the receiving bore via an after-suction opening i n flows into the damping space
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a control valve (6) with a control spool (22) arranged to be longitudinally displaceable in a longitudinal bore (20) of a housing (21), wherein the control valve (6) has at least one inlet port (25a; 25b) and one outlet port (26), wherein the control spool (22) can be actuated between a closed position (6a), in which the connection between the inlet port (25a; 25b) and the outlet port (26) is blocked, and at least one open position (6b; 6c), in which the inlet port (25a; 25b) is connected to the outlet port (26). A hydraulic damping device (40) is provided, which is operatively connected to the control spool (22) and with which damping of the movement of the control spool (22) can be generated.The hydraulic damping device (40) is designed such that the damping of the damping device (40) is effective when the control slide (22) moves from the closed position (6a) to the open position (6b; 6c) and the damping of the damping device (40) is ineffective when the control slide (22) moves from the open position (6b; 6c) to the closed position (6a).