Main Spindle Chuck With Pneumatic Clamping and Vibration Support

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Solution Overview

Problem

Conventional main spindle devices face challenges in high-speed rotation, size reduction, and fine adjustment of chuck clamping force due to balance issues, complexity in configuration, and the need for external components, making high-precision machining difficult.

Innovation Solution

A main spindle device with a cylindrical structure incorporating compressed air flow paths and pistons, where the cylinder and pistons are positioned near the collet to facilitate high-speed rotation, compact design, and precise clamping force adjustment, using a chuck unit with a collet grasping mechanism and a steady rest pipe to prevent vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If toggle method is used for clamping collet, then clamping force can be applied, but device becomes hard to rotate at high speed due to balance loss

Engineering Contradiction:
Improveclamping forceVSAvoidrotation speed
Core Design Contradiction:
ForceVSSpeed

Solution Approach 1:

The patent replaces the mechanical toggle system with a pneumatic system using compressed air to apply clamping force. The compressed air acts directly on the collet through the chuck, eliminating the need for mechanical toggles that cause balance issues during high-speed rotation. This substitution of mechanical components with pneumatic components resolves the contradiction between maintaining clamping force and achieving high-speed rotation.

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

2Force

If toggle method is used for clamping collet, then clamping force can be applied, but device size increases due to external components

Engineering Contradiction:
Improveclamping forceVSAvoiddevice size
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The patent integrates the compressed air storage and delivery system within the main spindle structure itself, rather than using external add-on components. The compressed air is stored in a reservoir integrated into the spindle and delivered directly to the chuck, merging multiple functions (air storage, air delivery, clamping) into a single compact unit. This integration eliminates the need for external cylinders and piping, thereby reducing overall device size while maintaining clamping capability.

Inventive Principle:
Principle #5Merging (Combining)

3Force

If toggle method is used for clamping collet, then clamping force can be applied, but fine adjustment of clamping force becomes difficult

Engineering Contradiction:
Improveclamping forceVSAvoidfine adjustment capability
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The patent enables fine adjustment of clamping force by controlling the pressure parameter of the compressed air. By varying the air pressure within a continuous range, the operator can precisely adjust the clamping force applied to the collet and workpiece. This continuous parameter control through pneumatic pressure provides much finer adjustment capability compared to the discrete mechanical adjustments required by toggle systems.

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If coned disc springs are positioned away from collet, then device structure is simplified, but balance is lost during high-speed rotation

Engineering Contradiction:
Improvestructural complexityVSAvoidrotation speed
Core Design Contradiction:
Device complexityVSSpeed

Solution Approach 1:

The patent eliminates the need for coned disc springs by using a pneumatic system. Compressed air is directed through passages in the spindle to act directly on the collet, removing the mechanical spring components entirely. This substitution not only simplifies the structure but also eliminates the balance problems associated with positioning spring components, enabling high-speed rotation.

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

5Force

If coned disc springs are made long to achieve sufficient spring force, then clamping force is adequate, but device size cannot be reduced

Engineering Contradiction:
Improveclamping forceVSAvoiddevice size
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The patent uses pneumatic pressure from compressed air to generate clamping force, replacing the mechanical spring system. The compressed air acts on a piston or directly on the collet through the chuck, generating sufficient clamping force in a compact space. This pneumatic approach eliminates the need for long spring components, allowing the device to maintain adequate clamping force while achieving significant size reduction.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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

Enables high-speed rotation, compact size, efficient power transmission, and precise machining with adjustable clamping force, effectively suppressing work vibration and enhancing machining accuracy.

Implementation Method 1

compressed air flow paths 11 and 12 are formed in the main spindle 1 along a direction in which an axial line of the main spindle 1 extends

Methodology Applied
Scientific EffectCompressed air flow: Pressure Gradient

Implementation Method 2

a piston 311 and a piston 321 which are positioned near the collet 6

Methodology Applied
Scientific EffectPneumatic actuation: Hydraulic Press

Data Source

PatentEP3733331B1Main spindle device
Publication Date: 2022.07.20 TSUGAMI CORP
  • EP3733331B1 patent drawingFigure 1
  • EP3733331B1 patent drawingFigure 2
  • EP3733331B1 patent drawingFigure 3

AI summary

A main spindle device has a main spindle (1) having a hollow hole, and a chuck unit (10) for grasping a work (W). A pipe unit (71) is inserted into the hollow hole of the main spindle (1) and receives insertion of the work (W) to thereby prevent the work (W) from vibrating when rotated together with the rotation of the main spindle. A support unit (72) supports the pipe unit (71) at one end of the main spindle (1) such that the axial line of the pipe unit (71) coincides with the axial line of the main spindle (1) and such that one end of the pipe unit (71) projects from the one end of the main spindle (1) to be positioned inside the chuck unit (10).