Spindle Motor Abnormality Detection via Stopping Time Analysis
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Solution Overview
Problem
Existing methods for detecting spindle abnormalities in machine tools are burdensome for operators and costly, as they require manual vibration measurement or continuous attachment of sensors, and struggle to accurately detect issues amidst factory noise.
Innovation Solution
An abnormality detecting device and method that measures spindle stopping time, temperature, and velocity, using sensors to compare data against normal conditions to judge spindle or spindle motor abnormalities, reducing operator burden and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vibration measuring equipment is attached to the spindle or spindle motor for automatic detection, then detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical vibration measurement systems with an electrical measurement system. Instead of attaching vibration sensors to the spindle, the invention measures the electrical current consumed by the spindle motor during free-running rotation. The current value reflects the mechanical resistance and bearing condition, providing indirect but accurate detection of spindle abnormalities without mechanical contact.
Solution Approach 2:
The patent uses electrical current as an intermediary parameter to detect mechanical conditions. Rather than directly measuring mechanical vibration or contact, the system measures the electrical current drawn by the motor, which serves as a mediator that reflects the mechanical state of the spindle and bearing through the relationship between electrical consumption and mechanical resistance.
2Measurement precision
If a vibration sensor is always attached to the spindle for automatic detection, then detection accuracy is improved, but cost increases
Solution Approach 1:
The patent replaces expensive mechanical vibration sensors with a simple electrical current measurement system. The current sensor or existing motor controller already present in the system can detect abnormalities through current analysis, eliminating the need for specialized vibration measurement equipment and reducing overall system cost.
Solution Approach 2:
The patent utilizes the existing spindle motor and its electrical characteristics as the detection mechanism. The motor itself provides the sensing function through its current consumption pattern, eliminating the need for separate detection devices. The system essentially detects abnormalities through the motor's own operational characteristics rather than requiring external sensing equipment.
3Measurement precision
If an operator manually detects abnormal noise by holding measuring equipment, then detection capability is improved, but ease of operation deteriorates
Solution Approach 1:
The patent replaces manual acoustic detection with automated electrical measurement. Instead of operators using their ears or handheld devices to listen for abnormal noises, the system automatically monitors electrical current parameters that reflect mechanical conditions, providing continuous objective detection without human involvement.
Solution Approach 2:
The patent implements continuous automated monitoring with feedback mechanisms. The system continuously measures current consumption, compares it against normal operating ranges, and can trigger alerts or stop operations when abnormalities are detected. This automated feedback loop replaces manual inspection with continuous self-monitoring, improving both detection capability and operational ease.
Data Source
AI summary
An abnormality detecting device and method for detecting a symptom of a failure of a spindle of a machine tool before the spindle malfunctions. The abnormality detecting device for detecting an abnormality or malfunction includes a spindle motor and a motor controller. The motor controller includes a time measuring part which measures a spindle stopping time from when a free-run of the spindle motor accelerated to a predetermined number of rotations is started to when the spindle motor is stopped, a storing part which stores the spindle stopping time measured by the time measuring part, and a comparing part which compares a plurality of data with respect to the spindle stopping time stored in the storing part, and judges as to whether or not an abnormality exists in the spindle or the spindle motor.