Swash Plate Hydraulic Feedback Link Vibration Control
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Solution Overview
Problem
The swash plate type variable displacement hydraulic rotary machines suffer from rattling movements and plastic deformations in the feedback link due to repeated axial displacements of the servo piston, leading to instability and reduced durability over time.
Innovation Solution
The feedback link is redesigned with an expansion spring and indented grooves on the servo piston, where the expansion spring's fore ends constantly engage with the groove sides, preventing rattling and attenuating high-frequency vibrations, ensuring stable displacement transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bifurcated holder spring is used to transmit displacement from the servo piston, then high frequency vibrations can be attenuated, but rattling movements occur when the servo piston reverses direction causing plastic deformation
Solution Approach 1:
The holder spring is divided into multiple holder portions (first holder portion and second holder portion) that can independently engage with the pin member. This segmentation allows each holder portion to maintain contact during direction reversals, preventing rattling movements while still providing vibration attenuation through the spring mechanism.
Solution Approach 2:
The holder spring is designed to maintain pre-compression or pre-tension engagement with the pin member before direction reversal occurs. This beforehand cushioning ensures that contact is maintained during transitions, preventing impact loads and rattling movements that would otherwise cause plastic deformation.
2Object-affected harmful factors
If the holder spring maintains constant engagement with the pin member, then rattling movements are prevented, but the spring action required for vibration attenuation is reduced
Solution Approach 1:
The holder spring is designed with dynamic engagement characteristics where the degree of engagement varies with the operating conditions. During normal operation, the spring maintains flexible contact for vibration attenuation, while during direction reversals, the geometry ensures continuous contact to prevent rattling, thus dynamically adapting to different operational phases.
Solution Approach 2:
The holder spring's engagement parameters (such as contact force, engagement depth, or stiffness) are designed to change based on the servo piston's position and velocity. This allows the spring to provide sufficient damping during steady-state operation while maintaining reliable contact during transient direction changes, optimizing both vibration attenuation and rattling prevention.
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
This configuration stabilizes the feedback link's operation over extended periods, preventing plastic deformations and enhancing the reliability and durability of the hydraulic rotary machine by consistently engaging the expansion spring with the servo piston's grooves, thus maintaining accurate displacement control.
Implementation Method 1
an expansion spring adapted to spread apart at fore distal ends by spring action; and in that an indented groove is provided on the outer peripheral side of the servo piston for abutting engagement with fore end portions of the expansion spring
Data Source
AI summary
A feedback link which transmits a movement of a servo piston to a control sleeve of a regulator is constituted by a link lever formed of a rigid material and an expansion spring formed of a spring material. The expansion spring is formed by folding a narrow leaf spring substantially into U-shape, and provided with a pair of convexly curved plate portions extending forward from a bent portion as a base end and spread apart from each other in a forward direction. On the other hand, an indented groove which is provided on the servo piston is composed of a parallel groove portion and a tapered groove portion. The convexly curved plate portions are engaged in the parallel groove portion of the indented groove in a resilient deformed state to transmit a displacement of the servo piston from the expansion spring to the link lever.