Self-Balancing Line Shaft With Movable Weights for Spindle Vibration

Solution Overview

Problem

Machine tools experience downtime and increased manufacturing costs due to the need for frequent shutdowns to correct rotating unbalance in spindle devices, leading to undesirable vibrations and chatter during high-speed machining.

Innovation Solution

A self-balancing line shaft system comprising a spindle device, a cutter tool holder, and a balancing assembly with an annular groove and movable weight members that adjust to counteract centrifugal force, maintaining balance and reducing vibrations without requiring frequent shutdowns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If measurement and correction of rotating unbalance is conducted regularly to maintain high machining precision, then machining precision is improved, but machine tool downtime increases and manufacturing cost increases

Engineering Contradiction:

Improvemachining precisionVSAvoidmachine tool downtime

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The balancing assembly automatically adjusts the weight members to counteract rotating unbalance during machine operation without requiring external intervention or shutdown. The system serves itself by using centrifugal force generated during rotation to move the weight members into positions that balance the spindle, eliminating the need for manual measurement and correction operations.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The weight members are designed to be movable rather than fixed, allowing them to dynamically adjust their positions in response to rotating unbalance conditions. This dynamic adjustment mechanism enables the system to adapt to changing balance conditions during operation, maintaining precision without requiring periodic shutdowns for correction.

Inventive Principle:

Principle #15Dynamics

2Manufacturing precision

If measurement and correction of rotating unbalance is conducted regularly to prevent chatter and vibration, then machining quality is improved, but productivity decreases due to increased downtime

Engineering Contradiction:

Improvemachining qualityVSAvoidproductivity

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The balancing assembly automatically adjusts the weight members to counteract rotating unbalance during machine operation without requiring external intervention or shutdown. The system serves itself by using centrifugal force generated during rotation to move the weight members into positions that balance the spindle, eliminating the need for manual measurement and correction operations.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The balancing assembly operates continuously during machine rotation, constantly adjusting the weight members to maintain balance. This continuous action ensures that chatter and vibration are prevented throughout operation without interruption, maintaining productivity while ensuring machining quality.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If fixed weight balancing is used to counteract rotating unbalance, then balance correction is achieved, but the system cannot adapt to changing unbalance conditions during operation

Engineering Contradiction:

Improvebalance correctionVSAvoidadaptability to changing conditions

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The weight members are designed to be movable rather than fixed, allowing them to dynamically adjust their positions in response to rotating unbalance conditions. This dynamic adjustment mechanism enables the system to adapt to changing balance conditions during operation, maintaining precision without requiring periodic shutdowns for correction.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system uses centrifugal force generated during rotation as feedback to automatically position the weight members. As the spindle rotates and unbalance conditions change, the centrifugal force naturally moves the weight members to positions that counteract the unbalance, creating a self-regulating feedback mechanism that adapts to changing conditions.

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

The self-balancing line shaft effectively minimizes downtime and manufacturing costs by maintaining balance and reducing vibrations during high-speed machining, allowing the machine tool to operate with reduced interruptions.

Implementation Method 1

A plurality of weight members (32) are movable and disposed in the annular groove (31) along the circle path

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS10953506B2Self-balancing line shaft of a machine tool

Publication Date: 2021.03.23 NAT FORMOSA UNIV

AI summary

A self-balancing line shaft of a machine tool includes a spindle device, a cutter tool holder and at least one balancing assembly. The spindle device includes a spindle extending along and rotatable about an axis, and at least one precision lock nut threadedly engaged with and rotated with the spindle. The cutter tool holder is coaxially connected and rotated with the spindle. The balancing assembly includes an annular groove formed in one of the precision lock nut and the cutter tool holder and extending along a circle path surrounding the axis, and a plurality of weight members disposed in the annular groove to be moved in a direction opposite to a rotation unbalance during rotation of the spindle such that the center of mass of the whole rotating system is close to the axis.