Central Torque Member Rotary Actuator for High Torque in Less Space
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Solution Overview
Problem
Existing fluid-powered rotary actuators are cumbersome, heavy, and costly due to their length and weight, necessitating a reduction in size and weight while maintaining durability and torque output.
Innovation Solution
The design incorporates a compact configuration with a torque member that transfers rotational force through a central portion within the actuator, eliminating the need for a large diameter shaft and allowing axial movement conversion into rotational movement efficiently, using intermeshing helical splines and a unique mounting system to reduce the actuator's length and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional large diameter shaft is used to transfer rotational force, then the actuator can maintain high torque output, but the actuator becomes longer and heavier
Solution Approach 1:
The patent places the torque member inside the piston sleeve, creating a nested configuration where the torque member is positioned within the hollow interior of the piston sleeve. This nesting arrangement eliminates the need for a large diameter shaft extending the full length of the actuator, as the torque is transferred through the internally positioned torque member, thereby reducing the actuator's overall length and weight while maintaining torque output capability
Solution Approach 2:
The patent transitions from a conventional shaft-based torque transfer (requiring radial space) to a central torque member positioned on the longitudinal axis within the piston sleeve. This dimensional reorganization allows torque transfer through the central axis rather than requiring a large radial shaft diameter, reducing the actuator's external dimensions and weight
2Force
If a conventional large diameter shaft is used to transfer rotational force, then the actuator can maintain high torque output, but the actuator becomes longer and heavier
Solution Approach 1:
The torque member is nested within the piston sleeve, allowing the torque transfer mechanism to be contained within the actuator's existing length rather than requiring an extended shaft. This nesting enables the actuator to achieve high torque output without increasing its overall length
Solution Approach 2:
The patent extracts the torque transfer function from the conventional external shaft and relocates it to a compact torque member positioned centrally within the piston sleeve. This extraction and relocation eliminates the need for a long external shaft, thereby reducing the actuator's overall length
3Reliability
If a complex mounting system is used to support the shaft, then the actuator can maintain durability and torque capacity, but the manufacturing cost increases
Solution Approach 1:
The piston sleeve serves multiple functions: it acts as the fluid-powered actuator component, provides structural support, and houses the torque member. This multi-functionality eliminates the need for separate complex mounting systems and bearing assemblies, simplifying manufacturing while maintaining durability and torque capacity
Solution Approach 2:
The patent merges the shaft support function into the piston sleeve structure itself, combining what would traditionally be separate components (shaft, bearings, mounting system) into an integrated piston sleeve-torque member assembly. This consolidation reduces the number of parts, simplifies manufacturing, and lowers cost while maintaining 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
This configuration results in a shorter, lighter, and cost-effective fluid-powered rotary actuator that maintains high torque output and durability, enhancing its applicability in various industrial applications.
Implementation Method 1
fluid pressure to one or the other opposing sides thereof to produce axial movement of the piston
Implementation Method 2
outer helical splines of the sleeve portion engage helical splines on the inward wall of the body sidewall to cause rotation of the sleeve portion
Data Source
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AI summary
A fluid-powered rotary actuator having a body with a shaft disposed therein and having a linear-to-rotary force-converting member mounted for longitudinal movement within said body in response to the selective application of pressurized fluid thereto. The actuator uses a torque member having a flange portion attached to the body or an external structure and a grooved central portion. A piston sleeve has outward grooves meshing with inward grooves on the shaft and inward grooves for meshing with outward grooves on the torque member central portion. The body sidewall is not used as a torque transmission surface during fluid-powered operation of the actuator.