Spool Valve Actuator With Avoidance Slot to Reduce Hysteresis
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Solution Overview
Problem
Existing spool type directional control valves suffer from hysteresis and asymmetrical hysteresis when the spool moves in different directions due to friction forces, particularly between the catcher and sealing ring, which affect their performance.
Innovation Solution
An actuator with a catcher and shaft design that includes avoidance slots and limiting portions to control spool movement, separating the operation process from other control means and minimizing friction-related hysteresis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a manual actuator with catcher and shaft is used to control spool movement, then the directional control valve can be operated manually, but friction forces between the catcher and sealing ring cause hysteresis and asymmetrical hysteresis
Solution Approach 1:
The patent extracts and removes the catcher component that causes friction and hysteresis. By eliminating the catcher entirely, the design achieves manual operation through direct shaft manipulation without the problematic intermediate component, thereby resolving the hysteresis issue while maintaining ease of operation
Solution Approach 2:
The patent introduces a groove structure as an alternative intermediary mechanism between the shaft and the sealing ring. This groove design allows the shaft to interact with the sealing ring in a way that minimizes friction and prevents the asymmetrical hysteresis caused by the traditional catcher design
2Productivity
If the shaft is directly connected to the catcher, then rotation of the shaft can drive the catcher to rotate and move the spool, but the catcher and sealing ring friction causes asymmetrical hysteresis in different directions
Solution Approach 1:
The patent removes the catcher component that causes asymmetrical hysteresis. By eliminating this intermediate component, the shaft can directly influence spool movement without the friction-induced directional inconsistencies, thereby maintaining productivity while improving directional consistency
Solution Approach 2:
Instead of using a catcher to transmit rotational motion from the shaft to the spool, the patent inverts the approach by allowing the shaft to directly interact with the sealing ring through a groove structure, reversing the traditional motion transmission path and eliminating the source of asymmetrical hysteresis
Data Source
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AI summary
An actuator and a spool type directional control valve. The actuator includes a catcher and a shaft. The catcher is provided with a first connecting portion and a second connecting portion. The first connecting portion is used to connect to a spool, and the second connecting portion includes a first limiting portion and an avoidance slot which are connected in a circumferential direction. The shaft includes a shaft body and a control member. The shaft body is used to connect to an operation mechanism and is driven to rotate by the operation mechanism, so that: the control member is capable of abutting against the first limiting portion, and driving the catcher to rotate forward by a first angle a via the first limiting portion so as to drive the spool move forward to a first working position; and the control member is capable of rotating freely in the avoidance slot, and the maximum rotation angle c of the control member in the avoidance slot is not less than the first angle a. With the actuator, the hysteresis of the directional control valve may be reduced, and asymmetrical hysteresis of the directional control valve when the spool moving in different directions can also be avoided.