Linear Actuator for Rotating Shaft Sealing and Pressure Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional linear actuators for rotating shaft assemblies face challenges such as fluid leakage, pressure loss, and heat buildup due to small clearances and constant lubrication needs, which require continuous pressurized fluid delivery and complex designs.
Innovation Solution
A linear actuator design that temporarily engages seals between rotating and non-rotating components to deliver pressurized fluid, allowing the rotating components to spin freely while maintaining fluid pressurization using valves, reducing the need for constant pressure contact and minimizing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If conventional rotary unions with small clearances are used to deliver pressurized fluid to rotating components, then fluid pressure can be maintained, but fluid leakage and pressure loss occur
Solution Approach 1:
The system uses periodic engagement of seals with the rotating shaft - seals are engaged during stationary periods to deliver pressurized fluid, then disengaged during rotation. This periodic action allows pressure maintenance when needed while avoiding continuous contact losses during operation
Solution Approach 2:
Pressurized fluid is delivered to the rotating components before rotation begins, while the seals are still engaged and can maintain pressure effectively. The fluid is pre-loaded into the system during the stationary phase, eliminating the need for continuous pressure delivery during rotation
2Stress or pressure
If small clearances are used in rotary unions to maintain pressure, then fluid pressure is maintained, but heat buildup occurs due to fluid shear
Solution Approach 1:
The seals are engaged only periodically during stationary phases rather than continuously during rotation. This eliminates continuous fluid shear through small clearances, preventing heat buildup while still allowing pressure delivery when the system is stationary
3Reliability
If constant lubrication is provided through small clearances in rotary unions, then components are lubricated, but fluid contamination and device failure occur
Solution Approach 1:
Lubrication and sealing occur periodically when seals are engaged during stationary phases, rather than continuously during rotation. This periodic contact reduces contamination exposure while still providing necessary lubrication and sealing functions
Solution Approach 2:
The sealing and lubrication function is extracted from the continuous rotary union structure and implemented as a separate periodic process using engageable seals. This separates the lubrication function from the continuous rotation path, reducing contamination risks
4Reliability
If pressure seals are placed between stationary and rotating structures to prevent leakage, then leakage is prevented, but excessive wear occurs due to constant contact
Solution Approach 1:
Pressure seals are engaged periodically during stationary phases to prevent leakage and maintain pressure, then disengaged during rotation. This periodic engagement prevents leakage when needed while eliminating constant contact wear during operation
Solution Approach 2:
The sealing system transitions from a static continuous contact design to a dynamic engageable/disengageable seal system. This allows the seals to be in contact only when pressure sealing is needed, adapting their state to the operational requirements
5Ease of operation
If mechanical systems are used to position and clamp work pieces, then positioning is achieved, but the systems cannot be adapted for rotating shaft assemblies
Solution Approach 1:
The linear actuator system is designed to perform multiple functions - it can position and clamp work pieces like traditional mechanical systems, and also adapt to rotating shaft assemblies by integrating with the rotational mechanism. The system combines linear actuation with rotational capability in a unified design
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 design reduces heat buildup, eliminates the need for continuous lubrication, and prevents fluid leakage by maintaining pressurization within the rotating components, enhancing the reliability and efficiency of the actuator.
Implementation Method 1
A passage isolation system for selectively isolating fluid communication between the first delivery passage and the first main passage and fluid communication between the second delivery passage and the second main passage
Implementation Method 2
A pressure limiting system for selectively blocking fluid communication through the first main passage and the second main passage
Implementation Method 3
A linear actuator for a rotating shaft assembly includes a cylinder member and a primary piston arranged within a cavity defined by the cylinder member
Data Source
AI summary
A linear actuator for a rotating shaft assembly includes a cylinder and a piston arranged within a cavity defined by the cylinder. Faces of the piston delimit first and second chambers within the cavity. A rotatable shaft fixed to the piston defines a first main passage in fluid communication with the first chamber and a second main passage in fluid communication with the second chamber. A pressure delivery body rotatably fixed to the rotatable shaft defines a first delivery passage in fluid communication with the first main passage and a second delivery passage in fluid communication with the second main passage. A passage isolation system selectively isolates fluid communication between the first delivery passage and the first main passage and fluid communication between the second delivery passage and the second main passage. A pressure limiting system selectively blocks fluid communication through the first and second main passages.