Helical Sector Gear Tooling for Uniform Powder Metal Compaction
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Solution Overview
Problem
Existing methods for forming helical sector gears, particularly those with powdered metal, face challenges in achieving uniform compaction due to the helical configuration, requiring both punch assemblies to rotate, which complicates the process and often necessitates machining operations for finishing.
Innovation Solution
A die set and method for forming helical sector gears that include a die with specific radial and circumferential surfaces, along with upper and lower punch assemblies, allowing for non-rotational and rotational components to compact powdered metal uniformly, enabling the formation of helical teeth that extend over a predetermined width with helical contours matching the gear's helix angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If both upper and lower punch assemblies rotate about the rotational axis to form helical teeth, then the helical configuration can be achieved, but the device complexity increases due to bearing requirements and rotational mechanisms
Solution Approach 1:
Instead of rotating the punch assemblies to form helical teeth, the invention inverts the approach by using stationary punch assemblies with linear motion. The helical configuration is achieved through the die cavity design and powder metal flow characteristics during compaction, eliminating the need for complex rotational mechanisms and bearings.
Solution Approach 2:
The invention replaces the mechanical rotational system (punch assemblies rotating about an axis with bearings) with a simpler linear compaction system. The helical tooth formation is achieved through the interaction of stationary punches with the powdered metal in the die cavity, substituting complex mechanical rotation with controlled powder flow and compaction pressure.
2Ease of manufacture
If traditional machining operations (milling or hobbing) are used to form helical sector gears, then the gear can be produced, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The invention performs preliminary action by forming the complete helical tooth configuration directly during the powder metal compaction process. The die cavity is pre-designed with the exact helical tooth geometry, allowing the gears to be formed in the desired shape before sintering, eliminating the need for subsequent machining operations like milling or hobbing.
Solution Approach 2:
The invention changes the manufacturing parameter from post-forming (machining) to pre-forming (compaction). By adjusting the die cavity geometry and compaction parameters, the helical tooth profile is directly formed during compaction, transforming the process from a two-step operation (compaction + machining) to a single-step operation (direct compaction forming).
Data Source
AI summary
A helical sector gear having a body and a gear segment having a plurality of helical teeth. The gear segment has a toothed sector, on which all of the helical teeth are formed, and spacing segments on the opposite circumferential ends of the toothed sector. Each of the spacing segments has a circumferential surface, which is longer than a pitch of the helical teeth, and a radial surface that is formed in a helical manner that conforms to the helix angle of helical teeth. A die set for forming the helical sector gear and a related method are also provided.