Machine Tool Selective Rail Locking for Precision Spindle Control

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Solution Overview

Problem

Machine tools with gear transmissions suffer from accuracy issues due to backlash and play, making them unsuitable for high-precision machining operations like C-axis contouring, especially when handling large workpieces.

Innovation Solution

A machine tool design featuring a dual motor spindle drive system with a selectively fixable transmission element, including a locking mechanism that aligns and engages rails to prevent play, allowing precise control of the spindle's rotation by switching between fixed and free configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a separate motor with gear transmission is used to rotate the spindle for large workpieces, then the machine tool can handle larger workpieces, but the accuracy to position the rotational angle of the spindle deteriorates due to backlash or play within the gear transmission

Engineering Contradiction:
Improveworkpiece sizeVSAvoidrotational angle positioning accuracy
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the transmission element selectively fixable and releasable. The transmission element can be fixed to the spindle in a fixed configuration for high-accuracy operations, and released to a free configuration when not needed. This dynamic switching capability allows the system to adapt between different operational requirements, resolving the contradiction between handling large workpieces and maintaining rotational positioning accuracy.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a gear transmission is used to drive the spindle, then the motor can be separated from the spindle allowing larger workpieces, but backlash and play within the transmission reduce machining accuracy

Engineering Contradiction:
Improvespindle drive configuration flexibilityVSAvoidmachining accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The transmission element's selective fixability allows the system to dynamically switch between fixed and free configurations. When fixed, it provides the necessary gear transmission for large workpiece handling; when free, it eliminates the backlash and play that compromise machining accuracy. This dynamic characteristic enables the system to maintain high adaptability while achieving high precision when needed.

Inventive Principle:
Principle #15Dynamics

3Speed

If two separate motors are used to drive a turntable for high- and medium-speed operations and low-speed indexing, then various speed requirements are met, but gear transmissions still induce inaccuracies for contouring applications

Engineering Contradiction:
Improverotational speed rangeVSAvoidcontouring accuracy
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The selectively fixable transmission element provides a dynamic solution that allows the system to switch between different operational modes. For high- and medium-speed operations, the transmission element can be in the free configuration allowing motor-driven rotation. For low-speed contouring operations requiring high precision, the transmission element can be fixed to eliminate backlash, thereby maintaining contouring accuracy across the full speed range.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3156160B1Machine tool
Publication Date: 2020.01.08 YAMAZAKI MAZAK KK
  • EP3156160B1 patent drawingFigure 1
  • EP3156160B1 patent drawingFigure 2
  • EP3156160B1 patent drawingFigure 3

AI summary

The invention provides a machine tool capable of machining a larger workpiece precisely and accurately. A machine tool (1) of the invention includes a first rotor (10), an enclosure (48), a first rail (58), a second rail (56), and a coupling member (66). The first rotor (10) is surrounded by the enclosure (48). The first rail (58) is disposed on the first rotor (10). The second rail (56) is disposed on the enclosure (48) so as to be brought into alignment with the first rail (58) at a predetermined rotational position. The coupling member (66) moves along the first rail (58) and the second rail (56), engages with the first rail (58) and the second rail (56) in a first state, and engages with the second rail (56) without engaging with the first rail (58) in a second state.