Pump Rotor Structure With Ring Rib for Compact Magnetic Bearing Support
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Solution Overview
Problem
Existing pump devices face issues with reduced shape accuracy and increased axial size due to thermal caulking of the drive magnet, leading to reduced magnetic characteristics and cooling inefficiency of the radial bearing and drive magnet.
Innovation Solution
The pump device incorporates a rotor design with a ring-shaped rib protruding inwardly from the drive magnet, allowing for a reduced axial length while maintaining magnetic attraction force, and features a flow path groove between the rotor components to enhance cooling, utilizing a U-shaped flow passage for improved fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the drive magnet is fixed by thermal caulking with a simple cylindrical structure, then the manufacturing process is simple, but the shape accuracy of the rotor reduces due to burr formation
Solution Approach 1:
The drive magnet is divided into a cylindrical body and a separate protruding portion (ring-shaped rib). This segmentation allows the protruding portion to serve as a stop that prevents the caulked part from forming burrs, while the cylindrical body maintains structural integrity. The segmentation resolves the contradiction by enabling simple thermal caulking without compromising shape accuracy.
Solution Approach 2:
A ring-shaped rib protruding in the radial direction is added to the drive magnet. This dimensional addition creates a stop feature that limits the caulking depth and prevents burr formation. The radial protrusion provides a geometric constraint that maintains shape accuracy while keeping the manufacturing process simple.
2Force
If the drive magnet is made longer in the axial direction to generate sufficient magnetic attracting force, then the magnetic force is sufficient to press the radial bearing, but the axial dimension of the rotor increases
Solution Approach 1:
The drive magnet incorporates a ring-shaped rib that protrudes in the radial direction rather than extending axially. This radial protrusion increases the effective volume and magnetic force generation capability without increasing the axial dimension. The magnetic force is enhanced through increased volume while the axial length remains compact.
3Length of moving object
If the axial length of the drive magnet is reduced to decrease rotor size, then the axial dimension is reduced, but the volume is insufficient to generate necessary magnetic attracting force
Solution Approach 1:
The drive magnet uses a ring-shaped rib protruding in the radial direction to increase volume without increasing axial length. This radial extension provides additional magnetic material volume for generating sufficient magnetic force while maintaining a compact axial dimension. The volume is increased through radial rather than axial growth.
4Temperature
If the gap between the drive magnet and cylindrical part is reduced to improve cooling efficiency, then the cooling effect is enhanced, but the flow passage area is reduced
Solution Approach 1:
The drive magnet is segmented with a ring-shaped rib that creates a defined flow passage structure. This segmentation organizes the fluid flow path, allowing for optimized gap dimensions that balance cooling efficiency with adequate flow area. The rib structure guides fluid flow while maintaining appropriate clearance for heat dissipation.
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 maintains shape accuracy, secures necessary magnetic force, and enhances cooling efficiency of the drive magnet and radial bearing, thereby prolonging component life and reducing temperature-related degradation.
Implementation Method 1
the radial bearing which is held inside the cylindrical part is pressed against a support member such as a washer in an axial direction by a magnetic attracting force generated by the drive magnet
Implementation Method 2
a fluid of the pump chamber flows through a gap between the drive magnet and the cylindrical part of the rotor to cool the drive magnet
Implementation Method 3
the radial bearing becomes a high temperature due to friction and the like
Data Source
AI summary
A pump device includes a motor having a rotor and a stator, and an impeller which is disposed in a pump chamber and is integrally rotated with the rotor. The rotor includes a rotor member having a first cylindrical part and a drive magnet surrounding the first cylindrical part. A radial bearing is held on an inner side of the first cylindrical part. The drive magnet has a second cylindrical part surrounding an outer periphery of the first cylindrical part and a ring-shaped rib which protrudes from an end of the second cylindrical part to an inner side. The rotor member has a seat part, which protrudes from the first cylindrical part to an outer side and supports an end of the second cylindrical part, and a caulked part which is enlarged from the first cylindrical part to an outer side and is overlapped with the ring-shaped rib.