Rotary Actuator Reduces Leakage via Segmented Pressure Chambers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional rotary actuators face significant challenges in reducing internal leakage of pressure medium due to seal failures and the need for high-pressure rotary seals, which complicates the maintenance of sealing characteristics and reduces the operational duration of seals.
Innovation Solution
The rotary actuator design eliminates the need for rotary sliding portions between the output shaft and ribs, vanes, and end caps by using a configuration with a case, cylinder, output shaft, arm, and piston, where pressure chambers are defined within the cylinder, allowing the pressure medium to drive the output shaft rotation without high-pressure seals, thereby reducing internal leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-pressure rotary seals are used to seal rotary sliding portions, then sealing performance is improved, but seal durability deteriorates due to early failure
Solution Approach 1:
The invention extracts and eliminates the high-pressure rotary seals from the rotary sliding portions by redesigning the pressure chamber configuration. The pressure fluid is contained in separate pressure chambers (first pressure chamber with the arm, second pressure chamber with the piston) that do not require rotary seals, thereby removing the source of seal failure while maintaining sealing functionality through alternative means.
Solution Approach 2:
The invention segments the pressure fluid containment into distinct separate chambers: a first pressure chamber containing the arm and a second pressure chamber containing the piston. This segmentation allows each chamber to be sealed independently without requiring high-pressure rotary seals at common rotary interfaces, thus improving seal durability while maintaining sealing performance.
2Reliability
If seals are inserted into grooves on ribs and vanes, then sealing is attempted, but leakage increases due to inadequate sealing at corner sections
Solution Approach 1:
The invention removes the problematic groove seal configuration entirely by adopting a different pressure chamber definition. Instead of using seals in grooves on ribs and vanes, the pressure chambers are defined by the piston and arm components themselves, eliminating the corner section sealing problems that cause leakage.
Solution Approach 2:
Instead of trying to seal rotary sliding portions with seals inserted into grooves (conventional approach), the invention inverts the approach by defining pressure chambers that naturally contain the pressure fluid without requiring such seals. The piston and arm configuration inherently creates sealed chambers, reversing the traditional sealing strategy.
3Power
If conventional rotary actuator structure is used, then torque output is achieved, but internal leakage of pressure medium increases
Solution Approach 1:
The invention segments the pressure fluid containment into separate first and second pressure chambers with distinct boundaries (arm and piston). This segmentation prevents pressure fluid from leaking between chambers and reduces internal leakage overall, while maintaining the torque output function through the piston-arm-cylinder mechanism.
Solution Approach 2:
The invention extracts the leakage problem by removing the conventional rotary sliding seal interfaces that cause pressure fluid leakage. The new pressure chamber configuration using the piston and arm eliminates these leakage paths while preserving the essential torque generation capability.
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 effectively minimizes internal leakage and reduces the number of high-pressure rotary seals required, enhancing the reliability and longevity of the sealing mechanism while maintaining responsiveness in servo control mechanisms.
Implementation Method 1
one end portion of the piston is rotatably connected to the arm, the cylinder is internally provided with a first pressure chamber in which the output shaft and the arm are housed, and a second pressure chamber that is defined by the cylinder and the piston and in which another end portion of the piston that is located opposite from the end portion thereof connected to the arm is slidably installed, and as a result of a pressure medium being fed into one of the first pressure chamber and the second pressure chamber and discharged from the other
Implementation Method 2
as a result of a pressure medium being fed into one of the first pressure chamber and the second pressure chamber and discharged from the other, the arm is displaced in the circumferential direction of the cylinder, and the output shaft pivots in the rotational direction
Data Source
AI summary
A cylinder is installed within a case, and an output shaft and an arm that is integrated thereto and extends in a radial direction are installed within the cylinder. A piston extending in an arc slides and is displaced in a circumferential direction of the cylinder within the cylinder. One end portion of the piston is rotatably connected to the arm. The cylinder is internally provided with a first pressure chamber in which the arm is housed and a second pressure chamber in which the other end portion of the arm is slidably installed. A pressure medium is fed into one of the first and second pressure chambers and discharged from the other, and the output shaft pivots in a rotational direction.