Motor assembly
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Solution Overview
Problem
Vacuum cleaner motors experience premature bearing wear due to eccentric rotation shafts caused by incorrect assembly, leading to increased vibration and reduced bearing life, especially when rotational speed is increased to maintain suction force with reduced motor size.
Innovation Solution
The motor design includes a housing cover with a guide rib that ensures proper alignment of bearings by maintaining contact with the motor housing's inner surface, preventing radial misalignment and minimizing bearing wear through precise coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the motor size is reduced to meet consumer demand for compact vacuum cleaners, then the motor dimensions decrease, but the bearing life is shortened due to increased rotational speed requirements and eccentricity effects
Solution Approach 1:
The guide rib is pre-formed on the housing cover before assembly, creating a predetermined alignment path that guides the housing cover into correct radial positioning during the assembly process. This preliminary structural feature prevents misalignment before it can occur, ensuring the rotation shaft remains centered even as motor size is reduced and rotational speed increases.
2Ease of operation
If fastening tolerance is provided to facilitate easy assembly of the bearing housing, then assembly ease is improved, but radial misalignment occurs leading to rotation shaft eccentricity and increased bearing wear
Solution Approach 1:
The guide rib acts as an intermediary element between the housing cover and motor housing. It provides a physical guide that mediates the assembly process, ensuring correct radial alignment while still allowing straightforward assembly. The guide rib translates the fastening tolerance into a controlled alignment feature rather than uncontrolled misalignment.
3Speed
If rotational speed is increased to maintain suction force with reduced motor size, then suction performance is maintained, but vibration increases and bearing wear accelerates due to eccentricity
Solution Approach 1:
The guide rib pre-aligns the housing cover radially before the motor operates at high speed. This preliminary alignment action ensures the rotation shaft is centered on the motor axis before rotation begins, preventing the development of eccentricity-induced vibration and bearing wear that would otherwise occur at high rotational speeds.
Data Source
AI summary
A motor includes a housing that has a bottom with a first bearing accommodation and a cylindrical side surface portion which extends from the bottom; a rotor assembly with a rotation shaft, and a rotor mounted on the rotation shaft and accommodated inside the housing; a stator assembly accommodated inside the housing and surrounding the rotor; a housing cover coupled to an upper end of the housing and having a second bearing accommodation; a flow guide on the housing cover; an impeller connected to the rotation shaft over the flow guide; an impeller cover; a first bearing accommodated in the first bearing accommodation and receiving the rotation shaft; and a second bearing accommodated in the second bearing accommodation and receiving the rotation shaft, the housing cover having a cover body with an opening, connection arms between the second bearing accommodation and the opening portion, and a guide rib.