Nested Drive Device Shaft Sealing for Vacuum Systems
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Solution Overview
Problem
Conventional drive devices with coaxial rotary shafts face challenges in maintaining sealability and miniaturization when operating in high-degree vacuum low-pressure environments, as existing sealing configurations are not effective in preventing pressure leaks and may interfere with motor placement.
Innovation Solution
The drive device incorporates a unique configuration with spiral ribbed output shafts, roller followers, and sealing members between the shafts and the case, ensuring effective separation of pressure zones and allowing for miniaturization by overlapping motors without elongating the shafts, while using different materials for shaft portions to achieve balanced strength and improved sealability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealing mechanisms are added to separate pressure zones in a drive device, then sealability is improved, but device complexity increases
Solution Approach 1:
The patent implements nesting by placing the first output shaft inside the second output shaft, creating a concentric arrangement where one shaft is housed within the other. This nested configuration allows sealing members to be positioned between the shafts and the case to separate pressure zones without adding external complexity to the device structure.
Solution Approach 2:
The patent divides the drive device into distinct pressure zones by positioning sealing members between the first output shaft and the case, and between the second output shaft and the case. This segmentation creates separate atmospheric pressure and low pressure spaces, improving sealability while maintaining a manageable structural division.
2Adaptability or versatility
If the shafts are elongated to accommodate motor placement, then adaptability is improved, but length of moving object increases
Solution Approach 1:
By nesting the first output shaft within the second output shaft, the patent enables both motors to be positioned along the same axial line without requiring extended shaft lengths. The concentric arrangement maximizes space utilization, allowing motor placement flexibility while keeping the overall device length compact.
3Volume of moving object
If the drive device is miniaturized, then volume of moving object is reduced, but motor placement becomes difficult
Solution Approach 1:
The nested shaft configuration allows both motors to be positioned concentrically along the same axis, enabling miniaturization of the overall device volume. This arrangement eliminates the need for extended shafts or distributed motor placements, achieving compact dimensions while maintaining full motor functionality and placement flexibility.
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 enhances sealability and maintainability, enabling the drive device to operate in high-degree vacuum conditions while maintaining airtightness and reducing the device's size, thus improving operational efficiency and space utilization in substrate processing systems.
Implementation Method 1
the output shaft including an outer peripheral surface having a rib formed in a spiral shape
Implementation Method 2
the roller followers being installed on an outer peripheral surface of the other end and engaged at a predetermined reduction gear ratio with the rib of the first motor
Implementation Method 3
a first sealing member located between the case and the outer peripheral surface of the first shaft body; and a second sealing member located between an inner peripheral surface of the first shaft body and an outer peripheral surface of the second shaft body
Data Source
AI summary
A drive device is provided to include: a case; a first motor and a second motor having an output shaft extending along a first axial line in the case and a second axial line parallel to the first axial line in the case, respectively; a first output shaft including a first shaft body and roller followers, the roller followers being engaged at a predetermined reduction gear ratio with the rib of the first motor; a second output shaft including a second shaft body and roller followers, the roller followers being engaged at a predetermined reduction gear ratio with the rib of the second motor; a first sealing member located between the case and the outer peripheral surface of the first shaft body; and a second sealing member located between an inner peripheral surface of the first shaft body and an outer peripheral surface of the second shaft body.