Vacuum Pump Magnetic Bearing Adjustment Through a Side Inlet
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Solution Overview
Problem
Existing vacuum pumps, particularly turbo-molecular pumps used for leak detectors, face challenges in adjusting the position of magnets due to the inlet port being formed at the side surface of the housing, complicating the application of a proper preload to the rolling bearing.
Innovation Solution
The vacuum pump design allows for easy adjustment of the magnet position by using a magnet nut that can be rotated via a tool inserted through the side inlet port, enabling precise adjustment of the preload on the rolling bearing, even when the inlet port is not above the magnet nut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the inlet port is formed at the side surface of the housing, then the vacuum pump structure is more compact or suitable for leak detector applications, but the adjustment of magnet position and preload application becomes difficult
Solution Approach 1:
The adjustment member is designed with a through-hole that allows insertion of a tool through the inlet port. The tool passes through the inlet port and into the through-hole of the adjustment member, enabling magnet position adjustment from the side surface without requiring direct access to the magnet nut. This nested configuration allows compact housing design while maintaining adjustability.
Solution Approach 2:
The adjustment member acts as an intermediary component between the inlet port and the magnet nut. It transmits the rotational force from the tool (inserted through the inlet port) to the magnet nut, enabling preload adjustment indirectly through the side surface inlet port without requiring direct access to the magnet nut location.
2Ease of operation
If the magnet nut is positioned such that the inlet port is above it, then magnet position adjustment is easy, but the housing design becomes less flexible for compact applications
Solution Approach 1:
The adjustment member serves multiple functions: it positions the magnet, transmits rotational force from tools inserted through the inlet port, and enables preload adjustment regardless of the inlet port's location on the housing. This multi-functional design allows the same mechanism to work whether the inlet port is above or at the side of the magnet nut, providing design flexibility.
Solution Approach 2:
The adjustment mechanism is designed to accept tool insertion from the inlet port direction (which can be from the side surface), transforming the adjustment operation into a three-dimensional access problem rather than requiring direct radial access to the magnet nut. This allows adjustment functionality to be maintained even when the inlet port is positioned at the side surface rather than above the magnet nut.
3Ease of operation
If a tool is inserted through the inlet port to rotate the magnet nut, then magnet position can be adjusted from the side surface, but the adjustment mechanism becomes more complex
Solution Approach 1:
The adjustment mechanism is segmented into distinct functional components: the adjustment member with the through-hole, the magnet nut, and the tool. This segmentation allows the adjustment member to be designed independently with the through-hole feature, separating the access path (through inlet port) from the adjustment function (rotating magnet nut), thereby reducing overall system complexity while improving accessibility.
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 design facilitates easy and precise preload adjustment on the rolling bearing, reducing mechanical noise and vibration, and enabling efficient operation of the vacuum pump even when the inlet port is not above the magnet nut.
Implementation Method 1
The magnetic bearing includes a rotary-side magnet arranged on the rotor and a stationary-side magnet arranged on a magnet holder portion fixed to the housing
Implementation Method 2
The rolling bearing needs to be applied with a preload in order to reduce rattling or noise upon rotation
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
In a vacuum pump (1), a housing (2) has a first inlet port (P11) at a side portion (13). A magnetic bearing (32) has a first permanent magnet (41) arranged at the periphery of a magnet holder portion (16) fixed to the housing (2) and a second permanent magnet (42) arranged at the rotor (3) to face the first permanent magnet (41) in a radial direction. A magnet nut (46) has, at an inner surface thereof, an internal thread shape to be engaged with an external thread shape formed at the periphery of the magnet holder portion (16). The magnet nut (46) moves in a direction along the rotation axis of the rotor (3) by rotating relative to the magnet holder portion (16), thereby adjusting the position of the first permanent magnet (41) with respect to the second permanent magnet (42). The magnet nut (46) has, at a side surface thereof, a through-hole (52c) in which a rotation tool (61) inserted through the first inlet port (P11) is to be locked.