Rotary Actuator Piston Layout for Lower Radial Force Loss
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Solution Overview
Problem
The existing rotary actuator design from the '696 Patent faces inefficiencies in transmitting the force of the pressure medium as a rotational force to the arm and output shaft, due to radial outward forces acting on the piston.
Innovation Solution
The rotary actuator design includes a piston with a top surface divided into three equally radial regions, with the connection point between the piston and the arm positioned on a virtual line orthogonal to the top surface and passing through the central region, minimizing directional differences and reducing radial outward forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the connection point between the piston and arm is positioned at the edge of the piston top surface, then the structure is simpler, but part of the pressure medium force acts radially outward reducing transmission efficiency
Solution Approach 1:
The top surface of the piston is divided into three equally divided regions in the radial direction, with the connection point positioned on the virtual line passing through the central region. This segmentation allows the force to be applied at an optimal location that balances structural simplicity with efficient force transmission, minimizing radial outward forces while maintaining ease of manufacture.
2Volume of moving object
If the cylinder is positioned closer to the piston connection point, then the actuator size is reduced, but friction between the piston and cylinder increases
Solution Approach 1:
The cylinder is positioned at a distance from the piston connection point in the circumferential direction rather than radially adjacent. This dimensional arrangement allows the cylinder to be closer to the rotation center while maintaining sufficient distance from the piston connection point, thereby reducing friction between the piston and cylinder while keeping the actuator compact.
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 allows for efficient transmission of the pressure medium's force to rotate the arm and output shaft, while reducing radial outward forces and friction, thereby enhancing the actuator's efficiency and performance.
Implementation Method 1
a force pushing the piston away from the cylinder acts on a first end of the cylinder, which is the end opposite to the connected portion of the piston
Implementation Method 2
an arm connecting the piston and the output shaft
Data Source
Figure 1
Figure 2
AI summary
A rotary actuator (10) includes: an output shaft (20); a housing (70) in which a cylinder (80) is defined, the cylinder having a circular arc shape around the output shaft; a piston (50) adapted to move inside the cylinder by action of a pressure medium; and an arm (30) connecting the piston and the output shaft. When viewed in plan from a direction parallel to the output shaft, a top surface (52A) of the piston has three equally divided regions divided in the radial direction from the center of the output shaft, the middle one of the three regions is a central region (R). When viewed in plan from the direction parallel to the output shaft, a connection point between the piston and the arm is situated on a virtual line that is orthogonal to the top surface and passes through the central region.