Toothed Hub Forming by Deep Drawing and Axial Upset Forging
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Solution Overview
Problem
Existing methods for producing internally or externally toothed hubs in sheet metal blanks, particularly for shaft-hub connections, are costly and require material removal, such as the complex and expensive laser process for creating an additional disc in pulley production.
Innovation Solution
A method involving deep drawing and collar pulling processes to form a cup-shaped depression in a thin sheet metal blank, followed by collar drawing and solid sheet metal forming to create a hub with internal or external teeth without material removal, using molding tools and punching tools to concentrate material and increase thickness for sufficient strength and torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an additional internally broached disc is used to achieve positive-locking shaft-hub connection, then the connection reliability is improved, but the manufacturing cost and process complexity increase significantly
Solution Approach 1:
The invention merges the hub body and the locking elements into a single integrated component formed from one sheet metal blank. The forming process simultaneously creates the hub structure and the internal toothing features, eliminating the need for separate broached discs and reducing assembly steps while maintaining connection reliability
Solution Approach 2:
The sheet metal blank is designed to perform multiple functions: it forms the hub body, creates the collar structure, and generates the internal toothing features all in one piece. This multi-functional approach replaces the need for separate components and complex manufacturing processes
2Strength
If deep drawing and collar drawing processes are used to concentrate material in the hub area, then the hub strength and torque transmission capability are improved, but the number of forming stages increases
Solution Approach 1:
The deep drawing process pre-concentrates material in the hub area by forming a cup-shaped depression, creating a thicker base region before the collar drawing step. This preliminary material concentration ensures sufficient material availability for the subsequent collar formation and toothing features, achieving the required hub strength
Solution Approach 2:
The forming process continues seamlessly from deep drawing to collar drawing to final toothing formation, with each stage building upon the previous stage's results. The material flow and forming action are continuous, minimizing idle time and maintaining productive action throughout the manufacturing sequence
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
This method allows for cost-effective production of hubs with increased torque transmission capabilities, eliminating the need for material removal and complex laser processes, while maintaining the structural integrity and strength of the hub.
Implementation Method 1
deep drawing of a cup-shaped depression with a round base in the sheet metal blank in several drawing stages such that the wall thickness of the sheet metal blank increases in the hub area
Implementation Method 2
production of a collar in the area of the base surface by means of collar drawing
Implementation Method 3
the collar material is compressed axially, forming the groove in the die (material flow)
Data Source
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AI summary
The invention relates to a method for producing a hub with an inner toothing from a sheet blank made of thin sheet metal, the method comprising the following steps: - deep drawing a cup-shaped indentation with a round base surface in the sheet blank in a number of drawing steps, in such a way that the thickness of the sheet blank increases in the region of the base surface; - producing a collar in the region of the base surface by means of collar drawing; - stabilising the collar by a mould resting flush against the outer surface thereof; - introducing a die having a negative of the inner toothing into the collar; and - subsequently performing bulk sheet-metal forming by axially upset forging the collar until the material in the region of the collar lies in the die. The invention also relates to a method for producing a hub having an outer toothing.