Helical Gear Green Compact Tooling for Load Redistribution
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Solution Overview
Problem
The powder-metallurgical production of sector gears with helical toothing faces challenges in tool load distribution, leading to tool chipping and reduced service life due to uneven load distribution.
Innovation Solution
The introduction of varying helix angles on the die, lower stamp, and upper stamp surfaces, specifically the second, third, and fourth helix angles, which differ from the first helix angle of the helical toothing, allows for a redistribution of the tool load, preventing chipping by adjusting the load distribution and increasing the contact surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform helix angles are used on the die and stamp surfaces, then the manufacturing process is simple, but the tool load is unevenly distributed causing tool chipping and reduced service life
Solution Approach 1:
The patent applies local quality by assigning different helix angles to different regions of the die and stamp surfaces. Specifically, the first helical toothing has a first helix angle, while the adjoining toothed edge surfaces have second and third helix angles that differ from the first. This local variation in geometric parameters redistributes the tool load across different contact areas, preventing concentrated stress that leads to tool chipping and extending tool service life.
Solution Approach 2:
The patent implements parameter changes by modifying the helix angle parameter across different surfaces of the tooling. The first helix angle of the helical toothing is made different from the second helix angle of the toothed edge surfaces on the die, and similarly for the stamps. This deliberate parameter variation transforms the uniform load distribution into a non-uniform distribution that avoids peak stresses, thereby improving tool reliability without requiring fundamental changes to the manufacturing process.
2Strength
If the second helix angle of the toothed edge surface equals the first helix angle of the helical toothing, then the tool design is simple, but the load concentration causes tool chipping
Solution Approach 1:
The patent applies local quality by making the second helix angle of the toothed edge surfaces different from the first helix angle of the helical toothing. This creates localized variations in contact mechanics at the edge surfaces, distributing the load more evenly and preventing the concentration of stresses that would otherwise lead to tool chipping. The local geometric modification enhances tool strength without requiring overall redesign.
Solution Approach 2:
The patent employs asymmetry by deliberately making the helix angles asymmetric across different tool surfaces. The first helix angle of the helical toothing is intentionally made different from the second helix angle of the adjoining toothed edge surfaces. This asymmetric configuration breaks the symmetry of load distribution, preventing concentrated loading at specific contact points and thereby reducing tool chipping while maintaining manufacturing feasibility.
Data Source
AI summary
A device for producing a gear green compact from a powder includes a die, an upper stamp, and a lower stamp, wherein the die has at least one helical toothing on an inner lateral surface, which helical toothing extends only over a partial area of the circumference of the inner lateral surface, and which has a first helix angle, wherein, adjoining the first helical toothing in a circumferential direction, one toothed edge surface is formed on each side, both of which have a second helix angle, wherein at least one of the second helix angles of the die is unequal to the first helix angle of the helical toothing of the die.