Chuck Jaw Wedge Structure for Reduced Top Jaw Lifting
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Solution Overview
Problem
The existing chuck mechanism experiences increased axial lifting of the top jaw due to reduced rigidity and increased reaction forces when holding large diameter works, caused by a thin and rigid chuck body and guide groove, leading to deformation and instability.
Innovation Solution
The chuck mechanism design includes a longer wedge with the end face positioned outward in the width direction relative to the narrow portion, reducing displacement and supporting the wide portion, and increasing the reinforcement rib's thickness and width, thus enhancing the chuck body's rigidity and reducing the need for a rib avoidance groove.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a large through hole is formed in the chuck body without changing the outer diameter, then the chuck body thickness is reduced, but the rigidity of the chuck body and the length of the guide groove are reduced, causing increased reaction force and elastic deformation of the master jaw
Solution Approach 1:
The master jaw is divided into a wide portion and a narrow portion, with the wide portion having increased thickness to provide local reinforcement. This segmentation allows the chuck body to maintain overall compactness while the reinforced wide portion of the master jaw locally compensates for the reduced rigidity caused by the larger through hole.
Solution Approach 2:
The wide portion of the master jaw is given increased thickness specifically at the location where reaction force is applied, creating local quality enhancement. This localized reinforcement addresses the rigidity issue at the critical stress point without increasing the overall size of the chuck body or master jaw.
2Length of moving object
If the master jaw length is reduced due to larger through hole, then the guide groove length is reduced, but the reaction force against the moment is increased, causing greater elastic deformation and top jaw lifting
Solution Approach 1:
The master jaw is segmented into wide and narrow portions, with the wide portion serving as a reinforced section that locally increases the moment of inertia. This segmentation allows the shorter master jaw to still provide sufficient resistance to the reaction force moment through the strategically positioned wide portion.
Solution Approach 2:
The solution addresses the length deficiency by transitioning to a different dimension - increasing the thickness (width dimension) of the wide portion of the master jaw. This dimensional change compensates for the reduced length in the axial direction by providing greater section modulus at the critical location.
3Volume of moving object
If the chuck body thickness is reduced to accommodate larger through hole, then the rigidity is reduced, but the area receiving reaction force in the master jaw becomes thinner and more prone to elastic deformation
Solution Approach 1:
The wide portion of the master jaw is given increased thickness specifically at the location where reaction force is applied, creating local quality enhancement. This localized reinforcement addresses the rigidity issue at the critical stress point without increasing the overall size of the chuck body or master jaw.
Solution Approach 2:
The master jaw functions as a composite structure with different thickness sections - the wide portion has increased thickness for reinforcement while the narrow portion maintains standard dimensions. This composite geometry optimizes the balance between material usage and structural strength.
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 design significantly reduces the lifting of the top jaw during work holding, maintaining stability even with larger through holes without changing the outer diameter, by distributing reaction forces more effectively and increasing the chuck body's rigidity.
Implementation Method 1
a wedge projecting toward an axially rear side is formed radially inside the wide portion... the plunger moves toward an axially rear side, whereby the master jaw moves toward radially inside by wedge action
Data Source
Figure 1
Figure 2~2(b)
Figure 3
AI summary
The chuck mechanism includes: a chuck body 10; an axially movable plunger 40 disposed inside the chuck body; and a master jaw 20 radially movable by wedge action caused by fitting the plunger in the master jaw 20. A guide groove 11 that radially guides the master jaw and has a T-shaped cross section is formed in the chuck body. The master jaw has a narrow portion 23 and a wide portion 24 that form a T-shaped cross section. A wedge 21 fitted in a wedge groove 41 of the plunger is formed radially inside the wide portion. The end face 21a of the wedge in the width direction is positioned outward in the width direction with respect to the end face 23a of the narrow portion in the width direction.