Lathe Spindle Clutch Alignment for Accurate Mode Switching

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Solution Overview

Problem

Existing machine tool electrical driving systems face issues with accurate engagement of serrations in the clutch device during mode switches, leading to vibrations, noises, and processing defects due to incorrect transmission of rotational force.

Innovation Solution

A machine tool electrical driving system with a position detection unit using encoder pulleys and a controller to align the drive pulley and clutch unit, ensuring accurate serration engagement by detecting and adjusting the position of the clutch unit before mode switches, utilizing a motion conversion unit and clutch driving unit for precise linear motion and rotation control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the clutch device components are linearly moved to switch between operation modes, then mode switching is enabled, but the serration engagement becomes inaccurate causing vibrations and noises

Engineering Contradiction:
Improvemode switching capabilityVSAvoidserration engagement accuracy
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs a feedback mechanism where the position of the clutch device components is continuously monitored during mode transitions. The control unit receives position information and adjusts the linear movement of clutch components to ensure precise serration alignment, thereby maintaining reliable engagement while enabling mode switching.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements preliminary positioning actions before the actual mode switch occurs. The control unit pre-adjusts the clutch device components to predetermined positions based on the target operation mode, ensuring that serrations are correctly aligned before power transmission begins, thus preventing vibrations and noises.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the spindle rotates at high speed in incorrect engagement state, then machining operation can be performed, but processing defects occur due to inaccurate rotational force transmission

Engineering Contradiction:
Improvemachining speedVSAvoidprocessing quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent uses a feedback control system that continuously monitors the engagement state of the clutch device. Before allowing high-speed spindle rotation, the system verifies that serrations are correctly engaged. The control unit receives position feedback and only permits machining operations when proper engagement is confirmed, thereby preventing processing defects while maintaining productivity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements a preliminary check mechanism that prevents high-speed operation when engagement is incorrect. The control unit detects the position of clutch components and blocks the spindle from rotating at high speed until proper serration engagement is achieved, thus avoiding processing defects before they can occur.

Inventive Principle:
Principle #9Preliminary anti-action

3Device complexity

If the position of the clutch unit is not detected in real time, then the system structure can be simpler, but the serration engagement accuracy deteriorates during mode transitions

Engineering Contradiction:
Improveposition detection systemVSAvoidclutch unit position accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent incorporates a position detection system that provides real-time feedback on the clutch unit's position during mode transitions. Sensors monitor the linear movement of clutch components and transmit position information to the control unit, which uses this feedback to precisely control the engagement of serrations, thereby achieving high measurement precision without excessive system complexity.

Inventive Principle:
Principle #23Feedback

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

Ensures accurate driving control in each operation mode by correctly engaging serrations, maintaining initial clamping force during mode transitions, and preventing processing defects.

Implementation Method 1

an encoder axially coupled with the second encoder pulley to detect an amount of rotation and a rotation position

Methodology Applied
Scientific EffectEncoder detection:

Implementation Method 2

a timing belt wound around the first encoder pulley and the second encoder pulley to transmit a rotational force of the first encoder pulley to the second encoder pulley

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

a motion conversion unit configured to convert a rotary motion of the drive pulley into a forward-rearward linear motion of the drawbar

Methodology Applied
Scientific EffectLead screw mechanism: Screw

Implementation Method 4

a clutch unit to selectively connect the spindle to the drive pulley and the housing

Methodology Applied
Scientific EffectMechanical engagement: Mechanical Fastener

Data Source

PatentEP3854519B1Electrical driving system for machine tool
Publication Date: 2024.05.15 KHAN WORKHLDG CO LTD
  • EP3854519B1 patent drawingFigure 1
  • EP3854519B1 patent drawingFigure 2~3
  • EP3854519B1 patent drawingFigure 4~5

AI summary

The present disclosure provides a machine tool ELECTRICAL DRIVING SYSTEM capable of selectively transmitting power of a motor for driving a spindle in a lathe which machines a workpiece to a rotation system including a drawbar and a spindle for driving a chuck, using a clutch mechanism. The machine tool ELECTRICAL DRIVING SYSTEM according to the present disclosure includes a housing, a hollow tubular spindle rotatably installed with respect to the housing inside the housing, a drive pulley rotatably installed with respect to the spindle outside the spindle, a spindle motor configured to rotate the drive pulley, a drawbar installed to be linearly movable with respect to the spindle but non-rotatable relative to the spindle in an axial direction inside the spindle to linearly move with respect to the spindle in the axial direction or to rotate together with the spindle, a motion conversion unit configured to convert a rotary motion of the drive pulley into a forward-rearward linear motion of the drawbar, a clutch unit installed outside the spindle (20) to selectively connect the spindle to the drive pulley and the housing, a position detection unit including an encoder connected to the drive pulley to detect an amount of rotation and a rotation position of the drive pulley, and a controller configured to perform a position adjustment process of rotating the drive pulley based on position information of the clutch unit detected by the position detection unit immediately before a spindle operation mode state is switched to a clamping operation mode and immediately before the clamping operation mode is switched to the spindle operation mode to align the position of the clutch unit.