Spindle Torque Equalization for Backlash-Free Drilling-Milling

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Solution Overview

Problem

Current drilling and milling devices on numerically controlled machine tools face challenges in achieving high cutting performance and surface quality, with limited tool and device lifespan, and existing solutions do not effectively address precision and backlash issues during machining operations.

Innovation Solution

A drilling and milling device with a spindle and drive shaft coupled via a gear, incorporating a device for equalizing torque and rotational speed, utilizing a centrifugal mass and a viscous brake to optimize mass distribution and damping, and featuring a control circuit for real-time adjustments based on sensor data to enhance machining quality and tool lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a conventional drilling and milling device is used on numerically controlled machine tools, then basic machining operations can be performed, but cutting performance and surface quality are limited

Engineering Contradiction:
Improvecutting performanceVSAvoidsurface quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the braking torque adjustable during operation. The control circuit allows the braking torque to be varied depending on the machining situation, enabling optimal performance for different cutting conditions and surface quality requirements, thus resolving the contradiction between productivity and manufacturing precision

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes parameters by introducing an adjustable braking torque that can be modified during operation. The control circuit enables parameter adjustment of the braking force to optimize both cutting performance and surface quality, allowing the system to adapt to different machining requirements

Inventive Principle:
Principle #35Parameter changes

2Duration of action of moving object

If existing drilling and milling devices are used, then machining operations can be completed, but tool lifespan and device service life are limited

Engineering Contradiction:
Improvetool lifespanVSAvoiddevice service life
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The patent applies preliminary action by preloading the bearing systems through the braking device before machining operations begin. This preliminary preload ensures optimal bearing operation conditions from the start, reducing wear and extending both tool lifespan and device service life

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control circuit implements feedback by monitoring machining conditions and adjusting the braking torque accordingly. This feedback mechanism helps maintain optimal operating parameters, preventing excessive wear and extending the durability of both tools and the device

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If a drilling and milling device without torque equalization is used, then the structure remains simple, but backlash and precision issues occur during machining

Engineering Contradiction:
Improvemachining precisionVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces a braking device as an intermediary element between the drive shaft and the environment. This intermediary component equalizes torque fluctuations and eliminates backlash without requiring complete redesign of the drive system, thus improving precision while limiting complexity increase

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces complex mechanical backlash compensation mechanisms with a braking-based torque equalization system. The brake-induced friction provides smooth torque equalization, substituting for more complex mechanical solutions and achieving precision improvement with controlled complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The solution significantly improves cutting performance, surface quality, and tool lifespan by eliminating backlash and preloading bearing systems, allowing for precise machining and adaptable braking torque, thus enhancing the overall processing quality and service life of the device and tools.

Implementation Method 1

incorporating a device for equalizing torque and rotational speed, utilizing a centrifugal mass and a viscous brake to optimize mass distribution and damping

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Implementation Method 2

utilizing a centrifugal mass and a viscous brake to optimize mass distribution and damping

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3523089B1Drilling-milling device having a device for evening out the torque and the rotational speed of the spindle
Publication Date: 2022.08.17 WTO VERMOGENSVERWALTUNG GMBH
  • EP3523089B1 patent drawingFigure 1
  • EP3523089B1 patent drawingFigure 2
  • EP3523089B1 patent drawingFigure 3

AI summary

The invention relates to a drilling-milling device, which is provided for use in turning centers or machining centers or other numerically controlled machine tools. In order to further improve the machining quality, especially in the case of an interrupted cut, and to further increase the operational life of the tools and the service life of the drilling-milling device, a device is provided for evening out the torque and/or the rotational velocity of the spindle.