Chuck Fixing Device Sliding Member Wear Dispersion

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing fixing devices in machine tools cause wear in the sliding member due to a significant difference in rotation speeds between the sliding member and the actuating lever, leading to wear in the axis line direction and rotation direction, particularly at specific angular positions.

Innovation Solution

A fixing device that synchronizes the rotation of the sliding member with the main spindle before contact with the actuating lever, using a rubber ring as a rotation transfer member, allowing the sliding member to rotate by inertia and reducing speed differences, thereby dispersing contact pressure and preventing focused wear at specific angular positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sliding member is always rotated integrally with the main spindle by providing a brake member, then wear in rotation direction can be prevented, but wear extending in axis direction easily occurs at specific angular positions

Engineering Contradiction:
Improvewear prevention in rotation directionVSAvoidwear extending in axis direction
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies periodic action by allowing the sliding member to rotate at variable speeds rather than constant speed. The sliding member rotates integrally with the main spindle during some portions of the cycle, and rotates by inertia during other portions, creating periodic variations in rotational speed that disperse contact points over time and prevent concentrated wear at specific angular positions.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements dynamics by transitioning from a static braking system to a dynamic inertial rotation system. Instead of always forcing integral rotation with a brake member, the system allows the sliding member to dynamically adjust its rotation state - sometimes rotating with the main spindle, sometimes rotating by inertia alone - which changes the contact characteristics and distributes wear more evenly.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If the sliding member rotates by inertia without integral rotation with main spindle, then wear in axis direction can be reduced, but wear in rotation direction increases due to speed difference

Engineering Contradiction:
Improvewear extending in axis directionVSAvoidwear prevention in rotation direction
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent uses periodic action by alternating between two rotation modes: integral rotation with the main spindle (preventing rotation direction wear) and inertial rotation (reducing axis direction wear). This periodic switching of rotation modes ensures that neither type of wear dominates, as each mode compensates for the limitations of the other during different phases of the operational cycle.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies parameter changes by varying the rotational speed parameter of the sliding member. Instead of maintaining a constant rotational speed relationship with the main spindle, the system allows the rotational speed to change dynamically - sometimes matching the main spindle speed, sometimes differing - which modifies the friction and wear characteristics to reduce overall wear in both directions.

Inventive Principle:
Principle #35Parameter changes

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

This solution effectively reduces wear in both the rotation and axis directions of the sliding member, preventing focused wear at specific angular positions by minimizing speed differences and dispersing contact pressure.

Implementation Method 1

a rubber ring (70) which rotates with the main spindle (90), and a bobbin (50) which is provided to be movable between a first position and a second position along an axis direction of the main spindle (90), rotates with the rubber ring (70) in contact with the rubber ring (70) in the first position in the movable range

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2647455B1Device for fixing workpiece in machine tool, and machine tool comprising fixing device
Publication Date: 2019.09.04 CITIZEN WATCH CO LTD
  • EP2647455B1 patent drawingFigure 1
  • EP2647455B1 patent drawingFigure 2
  • EP2647455B1 patent drawingFigure 3

AI summary

Wear of a sliding member is prevented or controlled in a portion of the sliding member at a specific angular position (phase) about an axis. A fixing device includes a chuck-actuating claw (40) which rotates with a main spindle (90), and is displaced to open and close a chuck section (20), a rubber ring (70) which rotates with the main spindle (90), and a bobbin (50) (sliding member) which is provided to be movable between a first position (P1) and a second position (P2) along an axis direction (MN) of the main spindle (90), rotates with the rubber ring (70) in contact with the rubber ring (70) in the first position (P1), rotates with the chuck-actuating claw (40) while displacing the chuck-actuating claw (40) in contact with the chuck-actuating claw (40) in the second position (P2), and does not have contact with both of the rubber ring (70) and the chuck-actuating claw (40) in a partial range between the first position (P1) and the second position (P2).