External Rotor Motor Bearing Monitoring via Stator Flange Sensor
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Solution Overview
Problem
Existing electric motor systems require complex and resource-intensive circuitry to monitor vibrations for bearing malfunctions, making them prone to failures and costly to maintain.
Innovation Solution
An external-rotor electric motor design with a vibration sensor attached directly to the stator flange near the bearing support tube, allowing simultaneous monitoring of both bearings with a single sensor, and integrating electronics in a partial housing for cost-effective and compact operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vibration sensors are installed on the outside of the motor housing with separate electronic units for signal evaluation, then bearing malfunction monitoring is achieved, but the system becomes complex and susceptible to malfunction
Solution Approach 1:
The patent integrates the vibration sensor directly into the motor housing structure, combining the sensing function with the structural component. The sensor is mounted on the stator housing in direct proximity to the bearings, eliminating the need for separate external monitoring units and complex signal evaluation electronics, thereby reducing system complexity while maintaining monitoring capability
Solution Approach 2:
The motor housing itself serves as an intermediary structure that both provides mechanical support and houses the vibration sensor. The housing acts as a mounting platform that positions the sensor optimally near the bearings without requiring additional external fixtures or complex mounting mechanisms
2Reliability
If multiple vibration sensors are used to monitor both bearings, then comprehensive monitoring is achieved, but the cost and component quantity increase
Solution Approach 1:
A single vibration sensor is positioned on the stator housing to perform multiple monitoring functions for both bearings simultaneously. The sensor location is optimized to capture vibration signals from both bearing positions, allowing one sensor to replace what would traditionally require two separate sensors, thereby reducing component quantity while maintaining comprehensive monitoring coverage
Solution Approach 2:
The sensor is positioned in a location on the stator housing that allows it to detect vibrations from both bearings through structural transmission. By utilizing the three-dimensional vibration transmission paths through the motor housing, a single sensor placed in an optimal location can monitor both bearings without requiring physical proximity to each bearing individually
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 enables reliable and cost-effective bearing function monitoring with minimal components and circuitry, facilitating early detection of failures and reducing maintenance costs, particularly suitable for mass-produced brushless external-rotor motors used in fans.
Implementation Method 1
a vibration sensor to pick up vibrations that occur in the electric motor and that are caused by malfunctions of the bearings
Implementation Method 2
the transmission of high-frequency structure-borne sound components is quite readily possible
Data Source
AI summary
The present invention relates to an electric motor, comprising a stator and a rotor that can rotate relative to the stator and that is mounted in bearing arrangements, and also comprising a motor housing and a vibration sensor to pick up vibrations that occur in the electric motor and that are caused by malfunctions of the bearing arrangements. The configuration provided here is that of an external-rotor motor. The stator has a bearing support tube that is connected at one end to a ring-shaped stator flange. Bearing arrangements are arranged at a distance from each other in the bearing support tube in the direction of a center longitudinal axis of the bearing support tube, in which a shaft of the rotor is supported. The vibration sensor is attached to the stator flange.