Woodworking Tool Spindle Temperature Monitoring

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Solution Overview

Problem

Woodworking machine tool spindles often experience pivot bearing damage due to high forces, leading to machine downtime and repair costs, with existing technologies failing to detect impending failures effectively.

Innovation Solution

Incorporating temperature sensors adjacent to pivot bearings within the spindle housing to monitor temperature, with signals transmitted via wires or wirelessly to an evaluation unit, which generates warnings or switches off the spindle to prevent damage, and using additional sensors to account for ambient temperature influences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If temperature sensors are installed adjacent to pivot bearings to monitor temperature, then early detection of bearing failure is achieved, but device complexity increases

Engineering Contradiction:
Improveearly detection of bearing failureVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces temperature sensors as intermediary devices that indirectly monitor the condition of pivot bearings by measuring temperature, which is a precursor to bearing failure. This allows early detection without directly interfacing with the bearing mechanism, thus improving reliability while adding minimal complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The temperature sensors perform preliminary monitoring of bearing conditions before actual failure occurs. By detecting temperature increases that precede bearing damage, the system enables preventive maintenance actions, improving reliability by catching issues early in their development.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If multiple temperature sensors are provided for multiple pivot bearings, then comprehensive monitoring is achieved, but manufacturing cost increases

Engineering Contradiction:
Improvecomprehensive monitoringVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The monitoring system is segmented into individual temperature sensors for each pivot bearing, allowing selective installation based on criticality. This enables comprehensive monitoring where needed while avoiding unnecessary sensors on less critical bearings, balancing reliability improvement with manufacturing cost control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Temperature monitoring is applied locally at each pivot bearing location rather than using a single general sensor. This localized approach ensures comprehensive monitoring of critical areas while allowing the system to be manufactured with the minimum necessary number of sensors for each specific application.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If the temperature sensor is placed very close to the pivot bearing, then measurement precision is improved, but the sensor may interfere with spindle adjustment movements

Engineering Contradiction:
Improvetemperature measurement precisionVSAvoidspindle adjustment movements
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The temperature sensor is positioned in a radially inward direction toward the pivot bearing rather than axially along the spindle movement path. This dimensional change in sensor placement allows close proximity for accurate temperature measurement while maintaining clear axial pathways for spindle adjustment movements without interference.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Reliability

If sensor lines are used to transmit signals from the temperature sensor, then signal transmission is reliable, but adjustment movements of the spindle axis are impaired

Engineering Contradiction:
Improvesignal transmissionVSAvoidadjustment movements
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The sensor signal transmission is extracted from the axial spindle region by routing sensor lines through the spindle housing structure rather than through the moving spindle components. This separation allows reliable signal transmission while keeping the adjustment movement paths clear and unobstructed.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Early detection of pivot bearing failure reduces unplanned downtimes and repair costs by providing timely notifications and preventing damage to surrounding machine parts.

Implementation Method 1

at least one temperature sensor with which the temperature of the pivot bearing can be detected

Methodology Applied
Scientific EffectTemperature sensing: Thermocouple

Data Source

PatentEP3205463B1Wood treatment tool spindle, moulding machine with such a tool spindle and method utilizing a tool spindle
Publication Date: 2020.11.18 MICHAEL WEINIG AG
  • EP3205463B1 patent drawingFigure 1
  • EP3205463B1 patent drawingFigure 2
  • EP3205463B1 patent drawingFigure 3

AI summary

The woodworking tool spindle has a spindle housing (15) in which a spindle shaft (16) with at least one rotary bearing (17, 18) is mounted. To monitor the temperature of the rotary bearing (17, 18), the tool spindle (4) is equipped with at least one temperature sensor (33), the signals of which are fed to at least one evaluation unit. Depending on this evaluation, the evaluation unit generates output signals. This allows for a reliable determination of whether the temperature of the rotary bearing (17, 18) approaches a critical value during operation of the tool spindle (4). At least one such tool spindle (4) is used in a moulder. Preferably, the temperature of the rotary bearing (17, 18) is monitored by the temperature sensor (33) in all tool spindles (4) of the moulder. The temperature sensor (33) continuously measures the temperature of the rotary bearing (17, 18) and feeds it to the evaluation unit.It compares the supplied temperature signals with a temperature limit and generates a signal when the supplied temperature signals reach the temperature limit.