Rotary Joint Noise Suppression via Elastic Bearing Mediators
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Solution Overview
Problem
Conventional rotary joints in polishing apparatuses generate noise due to improper fitting between the rotating body, housing, and bearings, especially when using resin for the rotating body, leading to vibrations and noise during low-speed rotation.
Innovation Solution
Incorporating elastic members, such as O-rings, between the rotating body and the bearings or between the housing and the bearings, and using restricting portions and flanges to press the bearings against the housing, which absorb gaps and reduce vibrations, thereby suppressing noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a bearing is installed by fitting between the rotating body and the housing, then the rotary joint can rotate, but proper fitting is difficult due to dimensional tolerances and assembly accuracy, creating gaps that generate vibrations and noises
Solution Approach 1:
An elastic member is introduced as an intermediary element between the bearing and the rotating body/housing. This elastic member fills the gaps created by dimensional tolerances and assembly inaccuracies, preventing vibrations and noises while allowing the bearing to rotate properly. The elastic member acts as a mediator that absorbs the fitting errors without compromising the rotation capability.
2Adaptability or versatility
If the rotating body is formed from resin to enable pure water circulation, then fluid circulation is improved, but proper fitting becomes difficult due to creep phenomenon and absolute strength of the resin
Solution Approach 1:
The elastic member serves as an intermediary that compensates for the dimensional changes and creep phenomenon inherent in resin materials. By placing the elastic member between the resin rotating body and the bearing, the system maintains proper fitting accuracy despite the resin's tendency to deform over time, while still allowing pure water circulation through the rotating body.
Solution Approach 2:
The elastic member changes its physical parameters (elastic deformation) to accommodate the creep phenomenon of the resin rotating body. As the resin undergoes dimensional changes due to creep, the elastic member adjusts its shape and size accordingly, maintaining the proper fit between the rotating body and the bearing throughout the operational lifecycle.
3Ease of manufacture
If gaps are created between the bearing and the rotating body or housing due to improper fitting, then assembly becomes easier, but vibrations are generated during rotation, especially at low rotational speeds
Solution Approach 1:
The elastic member is positioned as an intermediary between the bearing and the rotating body/housing to fill the gaps created by assembly tolerances. This eliminates the direct contact between mismatched surfaces that would otherwise generate vibrations during rotation, particularly at low speeds where the rotational energy is insufficient to overcome the gap-induced instability.
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
The solution effectively suppresses noise generation during the rotation of the rotary joint by absorbing gaps and reducing vibrations, ensuring quieter operation even at low rotational speeds.
Implementation Method 1
at least one elastic member is interposed at least either between the rotating body and the at least one bearing or between the housing and the at least one bearing
Data Source
AI summary
The invention suppresses generation of noises attributable to rotation of a rotary joint. A rotary joint includes a rotating body that rotates on a rotating axis A, a housing disposed so as to surround the rotating body, and at least one bearing disposed between the rotating body and the housing and adapted to support rotation of the rotating body. The rotary joint supplies fluids through fluid connection ports formed in the housing and fluid passages formed inside the rotating body to a polishing table having attached thereto a polishing pad for polishing a substrate or a holding portion that is adapted to hold the substrate while pressing the substrate against the polishing pad. At least one elastic member is interposed at least either between the rotating body and the at least one bearing or between the housing and the at least one bearing.