Rotary Vane Actuator Bearing Layout to Prevent Seal Leak Paths
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Solution Overview
Problem
Conventional rotary vane actuators experience fluid leak paths due to axial bearings wearing on the actuation member seals, leading to actuator dead band and internal fluid leakage.
Innovation Solution
The bearings are integrated into the axial surfaces of the vanes instead of the housing, ensuring they move with the actuation member and seals, preventing wear-induced leak paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If axial bearings are interference fit into the rotor cap and floor of the housing, then the bearings can support axial loads and facilitate rotation, but the bearings work loose from the housing surfaces and wear against the actuation member seals, creating internal fluid leak paths
Solution Approach 1:
Instead of fitting bearings into the housing (rotor cap and floor), the patent inverts the arrangement by fitting the bearings directly onto the actuation member (rotor and vane). This reversal prevents the bearings from working loose against the housing surfaces and eliminates the wear grooves that create fluid leak paths, while still providing the necessary axial load support and rotation facilitation.
2Productivity
If bearings are fit into the housing surfaces, then the actuation member can rotate, but the bearings create ledges that wear grooves into the seals, resulting in actuator dead band and excess internal fluid leakage
Solution Approach 1:
The patent applies inversion by relocating the bearings from the housing to the actuation member. This eliminates the ledge formation and groove wear that occur when bearings are pressed into housing surfaces, thereby preventing fluid leakage paths while maintaining rotation facilitation. The bearings on the actuation member rotate with it, avoiding relative motion that causes wear grooves.
3Ease of operation
If axial bearings are used to prevent friction along the main axis, then motion is facilitated, but the bearings wear on the actuation member seals, creating actuation internal fluid leak paths
Solution Approach 1:
By inverting the bearing placement from housing to actuation member, the patent eliminates the harmful interaction between bearings and seals. The bearings on the actuation member move together with it, preventing the relative motion that causes wear and fluid leakage, while still providing friction reduction along the main axis.
Data Source
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AI summary
Embodiments of the present invention describe the arrangement of bearings in actuators. In particular, the bearings are fit into a surface of the actuation member instead of into the housing for the actuation member. In an exemplary embodiment of a rotary vane actuator, the bearings are fit into the axial surfaces of the vane actuation member instead of in the floor and rotor cap of the housing. In this way, the problem of an axial bearing working loose and grinding a leak path into the actuation member is addressed.