Rotation Table Clamp Torque Measurement Without Workpiece Removal

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Solution Overview

Problem

Existing rotation tables fail to accurately measure clamp torque while a workpiece is attached, leading to potential slip and machine tool stoppages, requiring removal of the workpiece or machining jig for measurement.

Innovation Solution

A rotation table with a clamp torque measurement unit that includes a motor, detector, state monitoring unit, and measurement unit, allowing for clamp torque measurement without removing the workpiece, using motor torque information and rotation shaft state changes to determine clamp torque.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a jig for applying rotation torque is attached to measure clamp torque, then clamp torque measurement is enabled, but workpiece or machining jig must be removed from rotation table

Engineering Contradiction:

Improveclamp torque measurementVSAvoidmeasurement operation time

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The rotation table system integrates multiple functions: it can perform both workpiece machining and clamp torque measurement without requiring separate measurement equipment or workpiece removal. The motor and detector system serves dual purposes of driving the rotation table and measuring clamp torque.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own internal motor and detector components to measure clamp torque, eliminating the need for external measurement jigs. The rotation table measures its own clamp torque through the existing motor torque information and detector, making the measurement process self-contained.

Inventive Principle:

Principle #25Self-service

2Measurement precision

If external torque application method is used to measure clamp torque, then clamp torque can be measured, but measurement complexity and operation steps increase

Engineering Contradiction:

Improveclamp torque measurementVSAvoidmeasurement system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts the measurement function from external equipment and integrates it into the existing motor control system. By using the motor's torque information and the detector's rotation shaft state data, the measurement capability is extracted and embedded within the rotation table's control unit.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The measurement system merges the motor drive function with the measurement function. The control unit combines motor torque information with detector output to calculate clamp torque, merging two separate functions (driving and measuring) into a single integrated system.

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If clamp torque is not monitored, then machine tool can operate continuously, but rotation shaft may slip causing sudden stop and defective products

Engineering Contradiction:

Improvecontinuous operationVSAvoidrotation shaft holding stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system implements feedback monitoring of clamp torque through the detector and control unit. The detector continuously monitors rotation shaft state, and the control unit processes this information to detect clamp failures before they cause slip, providing early warning and enabling preventive maintenance.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary detection of clamp torque degradation before actual slip occurs. By monitoring clamp torque in advance and detecting deviations from normal values, the system can identify potential clamp failures early and take preventive action before they affect workpiece machining.

Inventive Principle:

Principle #10Preliminary action

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

Enables continuous operation of the machine tool by accurately measuring clamp torque in situ, preventing sudden stops and extending maintenance intervals by automatically adjusting clamp torque.

Implementation Method 1

a detector that detects rotation shaft state information relating to at least one of position, speed, or acceleration of the rotation shaft

Methodology Applied

Scientific EffectPosition detection:

Implementation Method 2

a motor of which one end of a rotation shaft is connected with the workpiece placement table

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 3

a clamp mechanism that holds the workpiece placement table at a stop position

Methodology Applied

Scientific EffectMechanical clamping: Friction

Implementation Method 4

measures a clamp torque based on motor torque information in accordance with the rotation instruction and a change in rotation shaft state

Methodology Applied

Scientific EffectTorque measurement:

Data Source

PatentUS9164006B2Rotation table with clamp torque measurement unit

Publication Date: 2015.10.20 FANUC LTD

AI summary

A rotation instruction is transmitted to a motor in a state where a workpiece placement table connected to a rotation shaft of the motor is clamped by a clamp mechanism provided in a rotation table, and a clamp torque is measured based on motor torque information in accordance with the rotation instruction and a change in rotation shaft state (a rotation position, a rotation speed, and the like).