Arcuate Rotary Piston Actuator for Wide-Angle High-Torque Motion
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Solution Overview
Problem
Existing rotary hydraulic actuators in heavy equipment applications face challenges in providing increased actuation speed, wide ranges of motion, efficiency in fluid power usage, and ease of maintenance, while also being compact and lightweight, with limited scalability to meet power-to-weight ratios, stiffness, holding capacities, and energy efficiency expectations.
Innovation Solution
A rotary piston actuator assembly featuring an arcuate-shaped piston and bearing sleeve assembly, with a rotor assembly and fluid delivery shaft, allowing for compact and lightweight design while providing high torque and range of motion, and incorporating a friction-reducing coating for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If linear hydraulic actuators are used in heavy equipment applications, then power transmission capability is sufficient, but actuation speed is limited and ranges of motion are restricted
Solution Approach 1:
The patent inverts the conventional linear motion approach by using rotary pistons that move in arcuate paths within a rotary actuator housing. This inversion allows the piston to directly generate rotational motion, achieving wide ranges of motion and high actuation speeds while maintaining power transmission capability suitable for heavy equipment applications.
Solution Approach 2:
The patent employs arcuate chambers and arcuate-shaped pistons with curved geometries. The arcuate bearing sleeve assembly and curved piston paths enable smooth rotational movement through wide angles, directly addressing the limitation of restricted ranges of motion in conventional linear actuators while maintaining structural integrity for heavy-duty applications.
2Power
If rotary hydraulic actuators are used for continuous inertial loading, then load holding is not required, but power-to-weight ratios and stiffness are insufficient for heavy equipment
Solution Approach 1:
The patent utilizes composite structural design combining arcuate bearing sleeve assemblies with rotary piston mechanisms. This composite approach integrates multiple functional elements (bearing surfaces, sealing chambers, fluid passages) into a unified rotary structure that achieves high power-to-weight ratios while maintaining the stiffness and holding capacity required for heavy equipment applications.
Solution Approach 2:
The rotary piston is nested within the arcuate chamber, which is itself contained within the rotary actuator housing. This nested configuration allows compact packaging of multiple functional components, reducing overall actuator weight while maintaining structural rigidity and power transmission capability for heavy-duty operations.
3Weight of moving object
If conventional actuator designs are scaled down for compactness, then weight is reduced, but field-serviceability and maintenance ease deteriorate
Solution Approach 1:
The rotary actuator is segmented into distinct modular components including the rotary piston, arcuate bearing sleeve assembly, sealing chambers, and fluid delivery system. This segmentation allows individual components to be independently accessed, inspected, and replaced in the field, maintaining ease of serviceability while achieving compact overall dimensions and reduced weight through efficient spatial arrangement.
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 enables enhanced actuation speed, wider ranges of motion, improved efficiency, and easier maintenance, while maintaining compactness and lightweight design, effectively addressing the limitations of existing rotary hydraulic actuators in heavy equipment applications.
Implementation Method 1
pistons of the rotor are moved by fluid under pressure
Implementation Method 2
fluid actuator comprising a housing defining a first chamber comprising a first cavity, a first fluid port in fluid communication with the first cavity, and a first open end
Implementation Method 3
a first arcuate bearing sleeve assembly having an inner surface configured to be contacted by a radially outer side of the first piston
Implementation Method 4
incorporating a friction-reducing coating for improved performance
Data Source
AI summary
The subject matter of this specification can be embodied in, among other things, a rotary actuator that includes a housing defining an arcuate chamber comprising a cavity, a rotor arm configured for rotary movement, an arcuate-shaped first piston disposed in said housing for reciprocal movement in the arcuate chamber, where a seal, the cavity, and the piston define a pressure chamber that includes part or all of the arcuate chamber, and a portion of the piston contacts the rotor arm, and a rotor assembly rotatably surrounding said housing and having a rotary output tube about the axis, wherein the rotor arm extends radially outward to the rotary output tube and the rotor arm is coupled to the rotary output tube.