Machine Tool Spindle Head Automatic Weight Estimation
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Solution Overview
Problem
Conventional machine tools require direct input of tool weight data, which can lead to erroneous inputs, and existing solutions are limited to specific types of machine tools or mechanisms, such as arm-type tool changers or magnetic bearing systems, and cannot accurately estimate tool weight for all spindle head configurations.
Innovation Solution
A machine tool with a load torque detection unit, data storage for relational data between tool weights and load torques, and a tool weight estimation unit that calculates tool weight based on detected load torque or drive current, allowing for automatic weight estimation without direct input, and includes a correction mechanism for deteriorating mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct input of tool weight data is required, then operator control is maintained, but erroneous input occurs reducing reliability
Solution Approach 1:
The machine tool performs self-measurement of tool weight using the spindle motor as a detection device. The control device automatically calculates tool weight based on motor current or torque data during spindle rotation, eliminating the need for manual operator input and preventing erroneous data entry while maintaining system reliability
Solution Approach 2:
The patent replaces manual input mechanisms with an automated detection system using electrical measurements. The control device substitutes direct operator input with indirect measurement through motor current or torque sensing, automatically deriving tool weight from electrical parameters during normal spindle operation
2Extent of automation
If existing automatic detection methods are used, then tool weight estimation is automated, but they are limited to specific machine tool types
Solution Approach 1:
The patent employs the spindle motor, a component present in all machine tools, to perform both its primary function of driving the spindle and the secondary function of detecting tool weight. By utilizing electrical parameters (current or torque) that are already measured for motor control, the system achieves universal applicability across different machine tool types without requiring specialized detection hardware
Solution Approach 2:
The control device acts as an intermediary that extracts tool weight information from existing motor operation data. Instead of requiring direct physical measurement devices, the control device processes electrical parameters (current or torque) that naturally occur during motor operation, serving as a mediator between the motor's electrical characteristics and the tool weight measurement function
3Measurement precision
If conventional detection methods are applied, then tool weight can be measured, but additional specialized devices are required increasing complexity
Solution Approach 1:
The patent merges the tool weight detection function with the existing spindle motor and control device. The same control device that manages motor operation also performs weight measurement by analyzing motor current or torque data, eliminating the need for separate detection hardware and reducing overall system complexity while maintaining measurement precision
Solution Approach 2:
The spindle motor serves itself by providing detection data for tool weight measurement through its own operational parameters. The motor's current or torque characteristics during rotation naturally contain information about the attached tool's weight, allowing the system to self-measure without external detection devices
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 accurate tool weight estimation and prevents erroneous inputs, optimizes spindle head operations, detects abnormalities in the drive system, and creates tool weight data for tool changers without direct input, ensuring proper operation and preventing processing defects.
Implementation Method 1
a load torque detection unit configured to detect a load torque applied to the spindle head drive motor
Implementation Method 2
obtain beforehand a relationship between a weight of a tool installed in the spindle head and a load torque that is applied to the spindle head drive motor under a predetermined drive condition
Data Source
AI summary
In a machine tool in which a spindle head is driven by a spindle head drive motor via a ball screw/nut mechanism, tools of different weights are each installed in the spindle head beforehand, a load torque applied to the spindle head drive motor is obtained, and relational data between the tool weight and the load torque is stored. When each tool is installed in the spindle head, the weight of the tool is estimated from, the load torque detected by a load torque detection unit while the spindle head is stopped, and the relational data between the tool weight and load torque.