Tool Clamping Device Capacitance Piston Position Detection
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Solution Overview
Problem
Existing tool clamping devices face challenges in detecting the position of the tool release piston accurately due to spatial constraints, such as rotatable lubricant supplies, leading to potential friction welding and damage, as well as delays and unscheduled spindle downtimes during tool changes.
Innovation Solution
A tool clamping device with an integrated electrical sensor system, where the tool release piston functions as a capacitor electrode, allowing its position to be detected by changing capacitance values based on its movement, ensuring reliable position detection and simplifying the sensor structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate position sensor is installed to detect the tool release piston position, then measurement precision is improved, but device complexity increases and spatial constraints are violated
Solution Approach 1:
The patent merges the position detection function directly into the tool release piston by utilizing the piston's own metallic conductivity as the capacitor electrode. This integration eliminates the need for separate position sensors and their associated mounting structures, thereby maintaining measurement precision while reducing device complexity and resolving spatial constraint issues.
2Productivity
If the tool release piston is moved quickly from the drawbar, then productivity is improved, but reliability deteriorates due to potential friction welding from incomplete movement
Solution Approach 1:
The patent implements feedback by continuously monitoring the tool release piston position through capacitance measurements. The control unit receives real-time position information and can verify whether the piston has completely moved away from the drawbar before initiating spindle rotation, thus preventing friction welding while maintaining high productivity through optimized timing.
3Reliability
If a predetermined waiting period is implemented before starting the work spindle, then reliability is improved by ensuring complete piston retraction, but productivity deteriorates due to workflow delay
Solution Approach 1:
The patent replaces the fixed waiting period with an active feedback-based position verification system. The control unit continuously monitors the tool release piston position via capacitance sensing and only permits spindle startup when complete piston retraction is confirmed, thereby maintaining reliability while eliminating unnecessary delays and improving overall workflow efficiency.
4Ease of operation
If hydraulic or pneumatic drive is used for the tool release piston, then ease of operation is improved, but reliability worsens due to potential faulty pressure conditions causing incomplete movement
Solution Approach 1:
The patent implements feedback monitoring of the tool release piston position through capacitance sensing. The control unit receives real-time position information and can detect incomplete movement caused by faulty pressure conditions, thereby maintaining the ease of hydraulic or pneumatic operation while improving reliability through active verification of movement completion.
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 solution enhances functional reliability, reduces unscheduled spindle downtimes, and optimizes the tool change process by providing real-time feedback, leading to increased efficiency and reduced manufacturing time per part.
Implementation Method 1
the tool release piston (3) functions as a capacitor electrode and thus forms an electrical capacitance with at least one other electrode (18 to 21)
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The device has an activation element that is moved by a drive between two positions. A sensor is fixed in a form of an electrical component for detecting a position of the activation element. A section of the activation element directly is formed as a component e.g. electrical switch, of the electrical component. A closing state of an electrical switch depends on a position of the activation element. A tool release piston (3) forms an electrical contact by a slip ring supported in an electrically high-impedance or insulated way relative to a hydraulic cylinder (2).