Machine Tool Drive Regulation for Spindle Safety
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Solution Overview
Problem
Existing motor regulation units in machine tools, such as speed regulation and excitation stop units, often lead to reduced maintenance efficiency and safety issues during door maintenance, as they either cause frequent errors or allow unintended movement of the main spindle during maintenance operations.
Innovation Solution
A drive regulation device that includes a detection unit for door states, an excitation operation unit for switching the motor between excitation and non-excitation states, and a speed regulation unit that only activates when the door is open and the motor is in an excitation state, ensuring the motor does not exceed a predetermined speed and preventing unintended rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the speed regulation unit is adopted to stop the motor when the door is open, then safety is improved, but maintenance efficiency deteriorates due to frequent error responses when manually rotating the main spindle
Solution Approach 1:
The speed regulation unit is dynamically switched on or off based on the door state. When the door is closed, the speed regulation unit is active to prevent unexpected high-speed rotation. When the door is opened, the speed regulation unit is deactivated to allow manual rotation during maintenance without triggering false errors, thus resolving the contradiction between safety and maintenance efficiency.
2Reliability
If the excitation stop unit is adopted to stop the motor when the door is open, then safety is improved, but the angular position of the main spindle is erroneously moved during maintenance
Solution Approach 1:
Instead of completely stopping the motor by cutting excitation, the speed regulation unit is selectively activated only when the door is closed. This localized control approach maintains motor excitation and angular position accuracy during maintenance while still providing safety protection when the door is closed, resolving the contradiction between safety and position accuracy.
3Reliability
If the allowable rotation speed is set to extremely low speed, then safety is improved, but maintenance operation becomes difficult
Solution Approach 1:
The speed regulation constraint is dynamically adjusted based on door state. When the door is closed, extremely low allowable speed ensures safety. When the door is opened, the speed regulation unit is deactivated allowing operators to rotate the main spindle at appropriate speeds for maintenance operations, thus resolving the contradiction between safety and ease of operation.
Data Source
AI summary
A drive regulation device for a machine tool that stops driving of a motor when a door (18) provided for a cover (17) for covering a driven body driven by the motor becomes to be in an open state includes a detection unit (21) detecting an open/closed state of the door (18) provided for the cover (17) for covering the driven body driven by the motor, an excitation operation unit (22) switching the motor between an excitation state and a non-excitation state, a speed regulation unit (23) stopping the motor, when the motor that has been stopped is rotated faster than a predetermined allowable rotation speed, and a speed-regulation switch unit (24) controlling the speed regulation unit (23), in a case where the detection unit (21) detects that the door (18) is in the open state, such that the speed regulation unit (23) works when the motor is in the excitation state, and the speed regulation unit (23) does not work when the motor is in the non-excitation state.