Machine Tool Spindle Drive Pulley and Encoder Clutch Alignment

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Solution Overview

Problem

Existing machine tool electrical driving systems face inefficiencies in power transmission from the spindle motor to the spindle, leading to decreased power transmission efficiency and inaccurate engagement of clutch serrations during mode switching, resulting in vibrations, noises, and processing defects.

Innovation Solution

A machine tool electrical driving system that includes a drive pulley connected to the spindle motor, a clutch unit with a serration engagement mechanism, and an encoder unit for accurate position detection, allowing direct power transmission and precise serration alignment for improved efficiency and accurate mode switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If power of the motor is transmitted to the spindle through the clutch device, then mode switching between clamping and machining operations is enabled, but power transmission efficiency decreases

Engineering Contradiction:
Improvemode switching capabilityVSAvoidpower transmission efficiency
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent extracts the clutch device from the main power transmission path between the motor and spindle. Instead of transmitting power through the clutch device during machining operations, the system directly couples the motor to the spindle, bypassing the clutch mechanism. This eliminates energy losses in the clutch while maintaining mode switching capability through a different configuration approach.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If the position of the spindle is not accurately known after stopping, then mode switching can be performed freely, but serration engagement in the clutch device becomes incorrect

Engineering Contradiction:
Improvemode switching freedomVSAvoidserration engagement accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent employs a sensor to detect the position of the clutch serration and provides feedback to the control system. Before switching to clamping mode, the control system uses this feedback information to accurately position the clutch, ensuring correct serration engagement. This feedback mechanism maintains precision while allowing flexible mode switching operations.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If the serration is not correctly engaged during mode switching, then operation flexibility is maintained, but rotational force transmission becomes inaccurate causing vibrations and noises

Engineering Contradiction:
Improveoperation flexibilityVSAvoidrotational force transmission accuracy
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent performs preliminary positioning of the clutch serration using the sensor-detected position information before initiating the mode switch. The control system advances or retracts the clutch to the correct position in advance, ensuring that when the clutch engages, the serrations are already properly aligned. This preliminary action prevents vibrations and noises while maintaining operational flexibility.

Inventive Principle:
Principle #10Preliminary action

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

Enhances power transmission efficiency and ensures accurate serration engagement, reducing vibrations and processing defects by directly transmitting rotational force from the drive pulley to the spindle and enabling precise control during mode switching.

Implementation Method 1

an encoder unit configured to detect a rotation position of the drive pulley

Methodology Applied
Scientific EffectEncoder detection:

Implementation Method 2

a motion conversion unit configured to receive a rotational force of the drive pulley and convert the rotation force into a forward-rearward motion of the drawbar

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP3854518B1Electrical driving system for machine tool
Publication Date: 2023.10.11 KHAN WORKHLDG CO LTD
  • EP3854518B1 patent drawingFigure 1~2
  • EP3854518B1 patent drawingFigure 3
  • EP3854518B1 patent drawingFigure 4a

AI summary

The present disclosure provides a machine tool electrical driving system and an operation method thereof capable of directly transmitting power of a spindle motor to a spindle through a drive pulley to improve power transmission efficiency. A machine tool electrical driving system of the present disclosure includes a housing, a hollow tubular spindle extending in a front-rear direction in the housing and rotatably installed with respect to the housing, a drive pulley fixedly installed to the spindle outside a rear portion of the spindle, a spindle motor configured to rotate the drive pulley, a chuck installed in a front end portion of the spindle and having a jaw clamping a workpiece, a drawbar installed to be linearly movable inside the spindle in a front-rear direction so that a front end portion is connected to the chuck to be linearly movable with respect to the chuck but non-rotatable relative to the chuck in the front-rear direction, a motion conversion unit configured to receive a rotational force of the drive pulley and convert the rotation force into a forward-rearward motion of the drawbar, a chuck locking unit configured to restrain or release a rotary motion of the chuck with respect to the housing, a clutch unit installed to be movable forward or rearward between a front portion of the spindle and a rear portion of the chuck and connecting the spindle to the chuck or separating the spindle from the chuck so that the spindle is rotatable relative to the chuck, and an encoder unit configured to detect a rotation position of the drive pulley.