Arcuate Tool Holder Positioning for Low-Friction Machine Tool Alignment
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Solution Overview
Problem
Existing machine tools face challenges in maintaining positioning accuracy and extending the service life of components due to high friction between the tool holder and the spindle, leading to increased wear and tear.
Innovation Solution
A tool holder positioning device with a first adapting member and a second adapting member, featuring non-circular protruding and recessed positioning portions with tapered arcuate abutment surfaces, which reduce contact area and friction, thereby enhancing positioning accuracy and service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the outer peripheral surfaces of the bosses and the groove inner surfaces are continuously in frictional contact to prevent rotation, then the positioning accuracy is improved, but the wear and tear increases and service life decreases
Solution Approach 1:
The patent applies curvature by designing the abutment surfaces as arcuate (curved) surfaces instead of flat surfaces. The first arcuate abutment surface and second arcuate abutment surface engage through point or line contact rather than surface contact, significantly reducing the contact area and friction between the tool holder positioning device and the machine head device, thereby reducing wear while maintaining positioning accuracy.
Solution Approach 2:
The patent implements local quality by creating different surface characteristics in different regions. The arcuate abutment surfaces are designed with specific curvature radii to achieve localized point or line contact, while other surfaces maintain their original properties. This localized change in contact characteristics reduces friction and wear at the critical engagement points without affecting other functional areas.
2Duration of action of stationary object
If clearance is increased between the outer peripheral surface and groove inner surface to reduce friction, then wear is reduced, but positioning accuracy decreases and component loosening occurs
Solution Approach 1:
The arcuate geometry of the abutment surfaces enables engagement through point or line contact rather than surface contact. This curved surface design allows the components to engage with minimal clearance while maintaining precise positioning, as the curvature naturally guides the engagement and prevents excessive movement or loosening.
Solution Approach 2:
Instead of increasing clearance to reduce friction (the conventional approach), the patent inverts the approach by using curved surfaces that achieve friction reduction through geometry rather than separation. The arcuate surfaces create a self-aligning engagement that maintains precision without requiring large clearances.
3Duration of action of stationary object
If large clearance is provided to reduce friction between contacting surfaces, then wear is reduced, but loosening and impact of components increases
Solution Approach 1:
The arcuate abutment surfaces are designed with specific curvature radii that ensure point or line contact during engagement. This curved geometry provides inherent stability by creating a self-centering effect, where the curvature guides the components into proper alignment and maintains stable engagement without excessive clearance, preventing loosening and impact during operation.
Data Source
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AI summary
A tool holder positioning device (4, 4') configured to be disposed on a machine head device (3) of a machine tool and for installation of a tool holder device (5) includes a first adapting member (41, 41') to be disposed on one of the machine tool and the tool holder device (5), and a second adapting member (42, 42') to be disposed on the other one of the machine tool and the tool holder device (5). The first adapting member (41, 41') includes a protruding positioning portion (412') having a plurality of angularly spaced-apart first abutment areas (413) each of which has a first arcuate abutment surface (416). The second adapting member (42, 42') includes a recessed positioning portion (422') having a plurality of angularly spaced-apart second abutment areas (423) corresponding in number to the first abutment areas (413) and each of which has a second arcuate abutment surface (426) abutting against the first arcuate abutment surface (416) when the tool holder positioning device (4, 4') is in an engaged state.