Motor Bearing Positioning via Segmented Axial Tubes
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Solution Overview
Problem
Conventional bearing positioning structures for motors are prone to deformation due to heat expansion and cold shrinkage, leading to unreliable positioning of the bearing, which can result in reduced motor lifespan and increased dust ingress.
Innovation Solution
A bearing positioning structure featuring a positioning member with a pressing portion and a coupling portion that securely engages with the axial tube, combined with a restraining member to limit axial movement of the rotor shaft, and additional features to prevent dust ingress, such as protrusions and inclined guiding faces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the axial tube is used to receive the bearing with supporting member and positioning member fixed by force-fitting, then the bearing can be positioned in the axial tube, but the axial tube deforms due to heat expansion and cold shrinkage leading to unreliable positioning
Solution Approach 1:
The axial tube is divided into two separate tubes: a first axial tube for receiving the supporting member and a second axial tube for receiving the positioning member. This segmentation isolates the thermal deformation effects in each tube, preventing cumulative deformation that would compromise bearing positioning reliability.
Solution Approach 2:
The bearing is introduced as an intermediary component between the first axial tube (with supporting member) and the second axial tube (with positioning member). This intermediary structure allows the bearing to be securely positioned while accommodating the separate thermal expansion and contraction of each axial tube without transmitting deformation stresses.
2Reliability
If the positioning member is force-fitted in the axial tube to prevent bearing movement, then bearing positioning is achieved, but the structure becomes complex and assembly reliability decreases
Solution Approach 1:
The positioning structure is segmented into distinct functional components: the first axial tube with supporting member for one end of the bearing, and the second axial tube with positioning member for the other end. This segmentation simplifies each individual structure while achieving reliable bearing positioning through the combination of both segments.
Solution Approach 2:
Instead of fitting the positioning member into the axial tube as in conventional designs, the invention inverts the approach by having the axial tubes receive and secure the bearing from opposite directions, with each tube independently positioned and fixed, thereby simplifying the overall assembly process.
3Reliability
If the through-hole diameter is smaller than the shaft end to prevent rotor disengagement, then rotor retention is achieved, but dust can enter through gaps leading to reduced motor life
Solution Approach 1:
The sealing structure is segmented with protrusions provided on both the first axial tube and the second axial tube at their respective ends. These protrusions create multiple sealing barriers that prevent dust ingress while maintaining the through-hole configuration for rotor shaft passage, thereby protecting the motor interior without compromising rotor retention.
Data Source
AI summary
A bearing positioning structure for a motor includes an axial tube and a positioning member. The positioning member includes a pressing portion and a coupling portion. The coupling portion of the positioning member is engaged with a coupling section of the axial tube for securely mounting the positioning member to the axial tube, with the pressing portion of the positioning member pressing against a bearing to position the bearing in the axial tube. In another example, the coupling portion of the positioning member engages with a coupling section on a stator.