Rotary Vane Actuator Seal Gap Limiting Mechanism
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Solution Overview
Problem
In rotary vane actuators, maintaining an appropriate force under fixing screws is challenging, leading to seal leakage or extrusion, which increases leakage, causes premature wear, and high friction, especially under high temperature conditions.
Innovation Solution
A vane assembly with a limiting portion that restricts the movement of the side-plate towards the vane, maintaining a seal gap to prevent over-clamping and extrusion of the seal, using a protrusion or spacer to limit compression and ensure proper seal positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fixing screw is tightened enough to prevent seal leakage, then sealing performance is improved, but the seal becomes extruded and deformed causing premature wear and high friction
Solution Approach 1:
A limiting portion (protrusion or spacer) is introduced as an intermediary element between the side-plate and the vane. This intermediary physically restricts the clamping force that can be applied to the seal, preventing over-compression and extrusion while still maintaining adequate sealing pressure. The limiting portion acts as a mechanical stop that mediates between the need for sealing and the need to preserve seal integrity.
Solution Approach 2:
The invention changes the mechanical parameters of the seal compression by introducing a physical limit on the clamping force. The limiting portion defines a maximum compression distance, thereby controlling the compression ratio and pressure applied to the seal. This parameter control prevents the seal from being compressed beyond its elastic limit, avoiding extrusion and deformation.
2Strength
If the fixing screw is not tightened enough, then seal deformation is avoided, but leakage occurs between the seal and vane interface
Solution Approach 1:
The limiting portion serves as a mediator that ensures minimum adequate clamping force is applied to the seal. By providing a defined contact surface and stop position, it guarantees that the seal receives sufficient compression to maintain sealing contact with the vane interface, preventing leakage while avoiding excessive compression.
Solution Approach 2:
The limiting portion is pre-installed in a fixed position relative to the vane or side-plate, establishing the correct clamping force parameter before the seal is subjected to operating conditions. This preliminary positioning ensures that when the fixing screw is tightened, the seal is compressed to the optimal degree from the outset, preventing both leakage and extrusion.
3Reliability
If high clamping force is applied to the seal, then sealing performance is improved, but friction and wear increase due to deformation
Solution Approach 1:
The limiting portion controls the clamping force parameter to remain within an optimal range. By preventing compression beyond a certain point, it ensures that the seal maintains sufficient contact pressure for sealing without exceeding the threshold that would cause deformation, excessive friction, and premature wear. This parameter optimization balances sealing performance with reduced harmful effects.
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 solution effectively prevents seal leakage and extrusion, maintaining efficient energy conversion and reducing wear and friction, even under high temperature conditions.
Implementation Method 1
A seal expander, made from a springy material such as steel, can also be sandwiched between the seal and side-plate and is shaped to contact and apply force to the inner surface of the seal lip and keep the seal lip in contact with the inner surface of the chamber cavity.
Implementation Method 2
the vane assembly has a limiting portion to limit the movement of the side-plate towards the vane so that a gap for the seal is maintained between the side-plate and the vane
Implementation Method 3
a retaining means for connecting the first side-plate to the rotatable vane
Implementation Method 4
pressure difference between the first and second chambers produces a torque on the vane resulting in rotational movement of the vane
Implementation Method 5
pressure difference between the first and second chambers produces a torque on the vane resulting in rotational movement of the vane
Data Source
AI summary
A rotary vane type actuator includes a vane assembly for converting pressure from a pressurized medium within the actuator into rotational movement. The vane assembly has a rotatable vane and a vane seal for preventing leakage of pressurized medium through or around the vane assembly. A side-plate is attached to the rotatable vane and the side-plate has a limiting protrusion that abuts the vane to maintain a gap between the vane and the side-plate so that the seal in the gap is not extruded from between the vane and side-plate.