Rotary Table Sealing Layout for Accurate Encoder Detection
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Solution Overview
Problem
The increase in the number of O-rings in rotary table devices leads to dynamic resistance, causing the center sleeve to twist and resulting in rotation non-detection zones and lost motion, which deteriorates rotation control performance and positioning accuracy.
Innovation Solution
The rotary table device design eliminates O-rings between the center shaft and center sleeve, using recesses and O-rings only between the center sleeve and housing to prevent fluid leakage, thereby avoiding dynamic resistance affecting the center shaft and maintaining encoder detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of O-rings is increased to prevent fluid leakage from an increased number of recesses, then fluid sealing is improved, but dynamic resistance increases causing center sleeve twist and encoder detection errors
Solution Approach 1:
The patent divides the sealing function into two independent locations: O-rings are placed only at the interface between the center sleeve and housing, while the interface between center shaft and center sleeve uses a different sealing approach. This segmentation isolates the dynamic resistance-generating O-rings from the rotating center shaft, preventing twist while maintaining fluid sealing through the recesses.
Solution Approach 2:
The patent extracts the O-rings from the center shaft-center sleeve interface, removing the source of dynamic resistance that causes center sleeve twist. The O-rings are relocated to only the center sleeve-housing interface, where they seal the recesses without interfering with encoder detection or causing rotational instability.
2Productivity
If the number of recesses is increased to distribute more air or oil, then fluid distribution capacity is improved, but the number of O-rings increases causing dynamic resistance and rotation control deterioration
Solution Approach 1:
The patent segments the sealing system so that multiple recesses can be provided for high fluid distribution capacity, but O-rings are concentrated at a single location (center sleeve-housing interface) rather than distributed at multiple interfaces. This reduces the total number of O-rings and their associated dynamic resistance while maintaining the ability to distribute large amounts of fluid.
3Reliability
If O-rings are provided between center sleeve and center shaft to prevent fluid leakage, then fluid sealing is improved, but dynamic resistance causes center sleeve twist and lost motion
Solution Approach 1:
The patent extracts the O-rings from the center shaft-center sleeve interface, eliminating the dynamic resistance that causes center sleeve twist and lost motion. Fluid sealing is maintained through alternative means at this interface while O-rings are concentrated at the stationary center sleeve-housing interface where they do not generate rotational resistance.
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 prevents deterioration in rotation control performance and positioning accuracy by eliminating dynamic resistance effects on the center shaft, ensuring stable fluid supply and accurate rotation detection.
Implementation Method 1
O-rings are disposed above and below each of the recesses in the axial direction to prevent leakage of the fluid from the recesses
Implementation Method 2
a rotary encoder disposed on the center shaft and the rotary table, the rotary encoder being configured to detect a rotation angle of the rotary table
Implementation Method 3
the fluid flows from a fluid flow path provided in the center sleeve into the recesses through the first path hole, and is supplied to a fluid flow path formed in the center shaft through the second path hole
Data Source
AI summary
There is provided a rotary table device including: a rotary table; a center shaft erected toward the rotary table; a housing including an inner peripheral surface having a circular cross section over a predetermined range along a rotation axis; a center sleeve including an outer peripheral surface having a circular cross section corresponding to the inner peripheral surface, and the outer peripheral surface being concentric with the inner peripheral surface; a plurality of recesses formed in at least one of the inner circumferential surface and the outer circumferential surface; a plurality of O-rings disposed to be sandwiched between the inner peripheral surface and the outer peripheral surface; an in-housing fluid flow path formed inside the housing; and a plurality of in-sleeve fluid flow paths formed inside the center sleeve.