Self-Drilling Screw Tip Structure for Chip Removal and Fastening
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Solution Overview
Problem
Conventional screws face limitations in efficiently cutting fibers during drilling, leading to chip accumulation, increased resistance, and potential workpiece cracking due to inadequate chip removal and limited groove area for receiving residual chips.
Innovation Solution
A screw design featuring a drill portion with outwardly extending cutting units and gradually reduced thickness, incorporating groove regions and drilling regions with inclined join walls, allowing for efficient cutting and chip accommodation, and a thread unit that continues the cutting operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional groove is formed on the shank, then the groove can accommodate chips, but the cutting effect is limited and fibers cannot be efficiently severed
Solution Approach 1:
The drill portion is segmented into multiple drilling regions with cutting units, groove regions, and join walls, transforming the single groove structure into a multi-functional segmented system that simultaneously cuts fibers and accommodates chips
Solution Approach 2:
The invention transitions from a two-dimensional groove surface to a three-dimensional structure with cutting units extending outward from groove regions, creating additional cutting surfaces and chip accommodation space in multiple dimensions
2Quantity of substance
If the groove area is increased to receive more chips, then chip capacity improves, but the groove blocks easily and causes larger resistance
Solution Approach 1:
Chips are extracted from the main shank groove area and directed into separate groove regions through cutting units, preventing chip accumulation and blockage in the primary drilling path while maintaining adequate chip capacity
Solution Approach 2:
Join walls serve as intermediary structures connecting groove regions to the main shank, facilitating smooth chip flow from cutting regions into groove accommodation areas without creating blockage points
3Length of moving object
If the drill body thickness is reduced to enlarge the drilled hole, then hole diameter increases, but structural strength may be compromised
Solution Approach 1:
The drill body exhibits local quality variation with different thicknesses in different regions - thicker at the base for strength, gradually reducing toward the end portion for enlarged hole diameter, optimizing both structural integrity and drilling performance
Solution Approach 2:
The drill body thickness dynamically transitions from the shank connection point toward the end portion, creating a gradient structure that adapts to different functional requirements along the length of the drill portion
4Productivity
If cutting units extend outward to enlarge hole diameter, then drilling speed improves, but device complexity increases
Solution Approach 1:
Cutting units, groove regions, and join walls are merged into an integrated drill portion structure that performs multiple functions simultaneously, reducing overall device complexity while maintaining high drilling productivity
Data Source
Figure 1
Figure 2
Figure 2A
AI summary
A screw (3) includes a head (31), a shank (32), a thread unit (33), and a drill portion (34). The drill portion (34) includes a drill body (341) with an end portion (3411) and opposite groove regions (342) and opposite drilling regions (343) respectively formed on the drill body (341) . Regarding each drilling region (343), on one side of each groove region (342) is formed a cutting unit (3431) which has a connecting section (34311) extending outwards from the groove region (342) and a cutting edge section (34312) connected to the connecting section (34311), and on the other side of the groove region (343) is mainly formed a first join wall (3432) which has a slanted surface so that the drill body (341) narrows gradually towards the end portion (3411). A first distance (L1) defined between two junctions (P1) where respective connecting sections (34311) meet respective cutting edge sections (34312) is greater than an outer diameter (OD) of the shank (32) . Accordingly, the screw (3) reams, cuts quickly, removes chips, and attains a stable fastening effect.