Servovalve Clamp Feedback Wear Reduction
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Solution Overview
Problem
Conventional servovalves experience wear and increased friction between the feedback member and the movable power distribution member due to mechanical connections, leading to reliability and lifetime issues, and existing solutions either fail to reduce wear effectively or introduce new friction problems.
Innovation Solution
A two-stage hydraulic servovalve with clamp means that securely connect the feedback member to the movable power distribution member without clearance, allowing transverse movement to reduce harmful forces and friction, using slender metal rods for flexibility and minimizing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mechanical connection with clearance (ball and groove) is used between the feedback member and movable power distribution member, then the servovalve can accommodate relative movement and reduce initial friction, but wear increases over time which disturbs servocontrol and reduces reliability
Solution Approach 1:
The invention changes the clearance parameter to zero by using a clamp connection that eliminates the gap between the feedback member and movable power distribution member. The clamp securely holds the feedback member against the movable member, transforming the connection from clearance-based to contact-based, thereby reducing wear while maintaining movement capability through the deformable feedback member's flexibility.
2Reliability
If a rigid clamping connection is used to eliminate clearance between the feedback member and movable power distribution member, then wear is reduced, but radial forces increase which generate high friction and may jam the valve
Solution Approach 1:
The invention uses the flexibility of the feedback member (blade or rod) to accommodate radial movements without generating harmful forces. The deformable feedback member can bend or deflect under radial loads, absorbing the forces that would otherwise be transmitted to the clamp and generate friction. This flexibility allows the rigid clamp to eliminate clearance while the feedback member's deformability prevents friction buildup.
3Reliability
If harder materials or surface treatments are applied to reduce wear, then friction wear decreases, but the complexity and difficulty of manufacturing increase due to the compact size of servovalve parts
Solution Approach 1:
The invention extracts the wear problem from the material surface and relocates it to the connection mechanism. Instead of treating the surfaces of the feedback member and movable power distribution member to reduce wear, the clamp connection eliminates relative movement between these surfaces entirely. The wear is effectively removed from the system by preventing the sliding action that causes it, simplifying manufacturing while improving 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 reduces wear and friction between the feedback member and the movable power distribution member, enhancing the servovalve's reliability and maintaining acceptable resolution and hysteresis performance.
Implementation Method 1
clamp means for clamping the feedback member, which means are arranged to allow a clamped portion of the feedback member to move relative to the movable power distribution member
Implementation Method 2
a deformable feedback member operationally connected to the rotor and to the movable power distribution member... allow a clamped portion of the feedback member to move relative to the movable power distribution member at least along a direction extending transversely
Implementation Method 3
The function of the power stage is to deliver a pressure or a flow rate proportional to an instruction transmitted to the pilot stage
Data Source
AI summary
A hydraulic servovalve having two stages and feedback members in which the movable power distribution member has clamp means for clamping the feedback member, while allowing a clamped portion of the feedback member at least one freedom of movement relative to the movable distribution member.