Sheet-Metal Flexspline Toothing for Faster Harmonic Drive Forming
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Solution Overview
Problem
Existing flexible transmission elements for harmonic drives face challenges in production technology that limit their efficiency and adaptability, particularly in achieving optimal elastic properties and simplified geometry.
Innovation Solution
A flexible transmission element with plate toothing produced using non-cutting shaping processes, where a hat-shaped sheet-metal part is deep-drawn and shaped using a profiled roller tool to form a sleeve section with outward toothing, and flange openings for enhanced elastic properties, eliminating the need for additional processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cutting methods are used to produce tooth structures, then manufacturing precision can be achieved, but production time increases and production technology becomes more complex
Solution Approach 1:
The patent replaces cutting methods with a non-cutting shaping process using a profiled roller tool that presses material radially outward to form teeth. This substitution of the mechanical system from removal-based to deformation-based manufacturing achieves both high precision and improved productivity.
2Reliability
If multiple processing steps are used to achieve optimal elastic properties, then transmission element performance improves, but production complexity increases
Solution Approach 1:
The patent combines multiple functions into a single integrated die structure that simultaneously forms the outer toothing, creates the thicker section for elastic properties, and shapes the overall geometry. This merging of processing steps into one operation reduces production complexity while maintaining optimal elastic properties.
Solution Approach 2:
The die is pre-configured with the complete tooth profile and thicker section geometry, allowing all necessary features to be formed in a single pressing operation. The preliminary preparation of the die structure enables subsequent one-step formation of the transmission element with all required characteristics.
3Ease of manufacture
If conventional shaping processes are used with profiled roller tools moving relative to the workpiece, then tooth structures can be formed, but additional reprocessing of outer toothing geometry is required
Solution Approach 1:
Instead of moving the profiled roller tool relative to the workpiece surface, the patent inverts the approach by holding the workpiece stationary and pressing material radially outward through a stationary die with the complete tooth profile. This inversion eliminates the need for subsequent reprocessing of the outer toothing geometry.
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
The solution enables the production of a transmission element with improved elastic flexibility and load-carrying capacity, suitable for harmonic drives and other applications, such as electric camshaft adjusters and reciprocating engine compression ratio variation, without requiring reprocessing of the outer toothing geometry.
Implementation Method 1
Material located in the thicker section is pressed radially outwardly into an inner toothed die, with which outer toothing of the transmission element is shaped
Data Source
AI summary
A flexible transmission element (1) which can be used, in particular in a harmonic drive (9) and which includes a sleeve-shaped, outer toothed section (3) and a flange (4) connected to this section (3), the outer toothing (8) of the sleeve-shaped section (3) is sheet metal toothing formed in a die.