Hot Forging Extrusion Tool for Helical Gear Teeth
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Solution Overview
Problem
Existing forging techniques, such as hot or semi-hot forging, struggle to accurately manufacture gear teeth with complex geometries, particularly helical teeth, on semi-products with varying central geometries, often requiring expensive thermochemical processes and are not suitable for producing transmission ring gears.
Innovation Solution
A hot or semi-hot forging machine equipped with a system for applying vertical compression force, featuring a movable tool holder with extrusion tools in the form of rings with varying forming rates, and a mechanism to transform vertical movement into rotational movement for helical gear production, allowing precise extrusion of gear teeth on the external face of semi-products with complex geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If hot or semi-hot forging techniques are used to form gear teeth, then the manufacturing process is simpler and more direct, but the equipment cannot produce gear teeth on workpieces with complex central geometry where thickness varies
Solution Approach 1:
The forging equipment is divided into multiple independent components: a fixed lower punch, a movable upper punch, and a rotatable extrusion tool with teeth. This segmentation allows each component to perform its specific function independently, enabling the system to handle complex geometries while maintaining ease of manufacture for the gear teeth themselves.
Solution Approach 2:
The extrusion tool is made rotatable around the workpiece axis, transforming a static forging setup into a dynamic one. This rotational capability allows the extrusion teeth to engage with the workpiece peripheral part at various positions, enabling gear tooth formation on workpieces with complex central geometry including flanges, hubs, and lightening forms.
2Manufacturing precision
If gear teeth are produced by machining an axisymmetric forged part, then the teeth can be precisely formed, but the material must have moderate hardness requiring complex and costly thermochemical hardening processes
Solution Approach 1:
The gear teeth are formed by extrusion during the forging process itself, before the workpiece is completed. This preliminary formation of teeth eliminates the need for subsequent machining operations and associated thermochemical hardening processes, as the extruded teeth can be directly hardened or used as-is depending on material properties.
Solution Approach 2:
The mechanical machining process is replaced with a thermomechanical extrusion process. Instead of cutting or forming teeth through mechanical removal or shaping operations that require hardening, the teeth are directly extruded into the workpiece material in its softened hot or semi-hot state, substituting complex mechanical-thermal processes with a more integrated approach.
3Stability of the object's composition
If a cylindrical mandrel is engaged in the bore of the workpiece to hold it during extrusion, then the workpiece is stabilized, but the equipment cannot produce gear teeth on workpieces with complex central geometry where thickness differs from the tooth portion
Solution Approach 1:
Instead of using an internal mandrel to support the workpiece from the inside, the invention uses external punches that clamp the workpiece periphery while allowing the central geometry to remain free. This inverted support approach enables accommodation of complex central geometries including flanges, hubs, and variable thickness sections while maintaining workpiece stability during extrusion.
4Manufacturing precision
If the extrusion tool is located entirely below the support in the post-forging position, then the gear teeth are completely formed, but the tool holder must move through a large vertical distance
Solution Approach 1:
The extrusion tool is given rotational freedom around the workpiece axis in addition to vertical movement. This adds a rotational dimension to the tool's degrees of freedom, allowing the teeth to be formed by rotational engagement rather than requiring the tool to travel the entire vertical distance, thus reducing cycle time while ensuring complete tooth formation.
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
Enables the precise and efficient production of straight or helical gear teeth on semi-products with complex central geometries, eliminating the need for costly thermochemical processes and allowing for subsequent finishing by rectification, thereby improving mechanical resistance and reducing production costs.
Implementation Method 1
a system for applying a vertical compressive force, movable in a downward vertical movement... to extrude the gear teeth of the semi-finished product
Implementation Method 2
intended to forge a straight or advantageously helical gear tooth on the outer face of revolution of a semi-finished product, by applying a warm or hot extrusion process
Data Source
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Figure 2A~3
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AI summary
Contents of the abstract. The invention relates to equipment for a hot or semi-hot forging machine (2) comprising: - a fixed punch (4) arranged to delimit a support seat for the semi-product (3) to be forged; - a counter punch (5) mounted movably vertically to occupy a lower position for which the punch and the counter punch immobilize the semi-product, - a tool holder (9) supporting an extrusion tool (10) and being arranged to receive the vertical compressive force of the application system (2b) of the forging machine to extrude the teeth of the semi-product during the vertical downward movement of the application system (2b) of the vertical compressive force.