Compact Linear-to-Rotary Actuator With Reduced Seal Side Loads
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Solution Overview
Problem
Existing rotary actuators face challenges such as seal leakage, limited rotary motion range, and increased space requirements, while linear actuators struggle to provide efficient rotary motion with compact design and leak-free performance.
Innovation Solution
A compact linear-to-rotary motion apparatus is developed, featuring a linear actuator with a piston shaft that translates within a piston chamber, connected to a rotor apparatus via torque linkages. This system converts linear motion into rotary motion, reducing side loads on seals and fitting within a compact design envelope similar to rotary actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If rotary actuators are used to deliver rotary motion efficiently, then space is conserved, but seal side loads increase causing leakage
Solution Approach 1:
The rotary actuator is segmented into modular components including a housing assembly, rotor assembly, and stator assembly that can be independently manufactured and assembled. This segmentation allows for optimized seal placement and reduced side loads on seals through proper distribution of mechanical stresses across multiple interface points.
2Reliability
If linear actuators are used to provide rotary motion, then leak-free performance is achieved, but space requirements increase
Solution Approach 1:
The invention replaces the traditional mechanical linear-to-rotary conversion mechanism with a magnetic coupling system. The stator assembly generates a rotating magnetic field that directly drives the rotor assembly, eliminating the need for mechanical linkages and significantly reducing the space required while maintaining leak-free performance through magnetic rather than mechanical power transmission.
3Power
If rotary actuators are designed to maintain constant torque, then performance is improved, but device complexity increases
Solution Approach 1:
The stator assembly utilizes variable geometry windings that can be electronically controlled to produce a rotating magnetic field with constant magnitude. By changing the electrical parameters (current magnitude and phase angles) rather than mechanical parameters, the actuator maintains constant torque output while keeping the mechanical structure relatively simple and modular.
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 apparatus achieves efficient rotary motion with reduced side loads on seals, fits within a compact space, and maintains a flat torque curve, addressing the limitations of existing technologies while providing a reliable and space-efficient solution.
Implementation Method 1
a first torque linkage having a first torque linkage end pivotably connected to the rotor arm end of the rotor arm, and a second torque linkage end opposite the first torque linkage end and pivotably connected to the first piston shaft end of the first piston shaft
Data Source
AI summary
The subject matter of this specification can be embodied in, among other things, a linear-to-rotary apparatus that includes a linear actuator having an actuator housing including a piston chamber, a piston shaft disposed in the piston chamber, and a rotor apparatus. The rotor apparatus includes a rotary joint defining a rotational axis, a rotor arm extending radially from the rotary joint and configured to at least partially pivot about the rotary joint, and a torque linkage pivotably connected to the rotor arm. The torque linkage is also attached to an end of the piston shaft of the piston at a pivot connection joint, where the pivot connection joint defines a pivot axis that is substantially perpendicular to the translation axis of the piston shaft.