Machine Tool Door Torque Detection Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Machine tools with automatic door opening/closing systems face safety risks due to potential collisions or malfunctions, often requiring expensive sensors to prevent injuries, which increases costs.
Innovation Solution
A door opening/closing device that includes a disturbance torque estimation unit, torque comparison unit, and motor stop unit to detect abnormal loads on the door drive motor, allowing for safe operation without expensive sensors by stopping the door movement when excessive torque is detected and reversing it with controlled speed adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an area sensor is used to detect human or object existence in the machine, then safety is improved, but cost increases
Solution Approach 1:
The patent replaces the optical/electronic area sensor system with a mechanical torque detection system. The disturbance torque estimation unit estimates torque applied to the door opening/closing drive motor, and the torque comparison unit compares this torque to predetermined thresholds. This mechanical approach uses the existing motor's torque characteristics to detect obstacles, eliminating the need for expensive area sensors while maintaining safety functionality.
Solution Approach 2:
The system uses the door opening/closing drive motor's own torque characteristics to detect obstacles and ensure safety. The disturbance torque estimation unit utilizes torque information already generated during motor operation, and the motor stop unit automatically stops the door operation when abnormal torque is detected. This self-service approach allows the existing motor system to perform both its primary function and safety detection without requiring separate expensive sensing components.
2Reliability
If the door opening/closing operation is stopped when disturbance torque exceeds limits, then safety is improved, but productivity decreases
Solution Approach 1:
The patent implements dynamic control of the door opening/closing operation based on real-time torque conditions. The motor stop unit stops the operation only when disturbance torque exceeds predetermined limits, while allowing normal operation to proceed at full speed when torque is within acceptable ranges. This dynamic approach adapts the door's motion characteristics to current conditions, maintaining high productivity during normal operation while ensuring safety when obstacles are detected.
Data Source
AI summary
A machine tool according to the present invention is provided with a door opening/closing device including a movable door, a door opening/closing drive motor configured to drive the movable door, a power transferring mechanism configured to transfer power of the door opening/closing drive motor to the movable door. The machine tool includes a disturbance torque estimation unit configured to estimate a disturbance torque applied to the door opening/closing drive motor at an opening/closing operation of the movable door, a torque comparison unit configured to compare the disturbance torque estimated by the disturbance torque estimation unit to a predetermined first upper limit and a predetermined first lower limit, and a motor stop unit configured to stop the opening/closing operation of the movable door when the torque comparison unit determines that the disturbance torque is larger than the first upper limit or smaller than the first lower limit.