Pot-Shaped Harmonic Drive Coupling for High Torque in Tight Space
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Solution Overview
Problem
Conventional harmonic drives face challenges in achieving a favorable ratio between transmittable torque and required installation space, while also needing a production-friendly structure.
Innovation Solution
A pot-shaped flexible transmission element is used, coupled non-rotatably to the drive element with a form-fitting coupling and contact flanks to minimize play, allowing for high torque transmission with reduced torque irregularities and improved durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a collar-shaped flexible transmission element is used, then the structure is simple and easy to manufacture, but the torque-to-space ratio is reduced
Solution Approach 1:
The patent uses a pot-shaped flexible transmission element instead of a collar-shaped one. This pot-shaped element has a closed bottom that extends radially inward, creating a more compact structure that improves the torque-to-space ratio while maintaining manufacturing feasibility through elastic deformation principles
Solution Approach 2:
The invention transitions from a two-dimensional collar shape to a three-dimensional pot shape by adding a closed bottom surface. This dimensional change allows the flexible element to engage teeth more effectively and transmit torque more efficiently within a smaller space envelope
2Power
If a pot-shaped flexible transmission element is used, then the torque-to-space ratio is improved, but the structure becomes more complex
Solution Approach 1:
The pot-shaped flexible transmission element utilizes elastic deformation of a thin-walled structure to achieve the desired three-dimensional form. The flexibility of the shell material allows the complex pot shape to be manufactured as a single piece without internal supports or complex assembly, reducing overall structural complexity
Solution Approach 2:
The invention changes the geometric parameters of the flexible element by introducing a closed bottom with specific curvature and thickness. These parameter changes optimize the torque-to-space ratio while the material selection and dimensional relationships maintain manufacturing simplicity
3Power
If the flexible transmission element is coupled rigidly to the drive element, then torque transmission is efficient, but play and tilting moments increase
Solution Approach 1:
The pot-shaped flexible transmission element is coupled to the drive element through a form-fitting connection that allows controlled elastic deformation. This flexible coupling absorbs play and reduces tilting moments by accommodating misalignments through the elastic properties of the pot-shaped structure, maintaining reliable torque transmission without rigid constraints
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 design enhances the torque-to-space ratio, minimizes torque irregularities, and improves controllability and durability by using a pot-shaped flexible transmission element with a form-fitting coupling and contact flanks, reducing play and tilting moments.
Implementation Method 1
a flexible, pot-shaped transmission element (26) designed to be deformed elastically
Implementation Method 2
contact flanks (40) which bear against one another in a form-fitting manner suitable for minimizing play
Data Source
AI summary
A harmonic drive, more particularly in an electromechanical camshaft phaser, comprises a drive element (2), a flexible transmission element (26) connected to the drive element (2) and having external teeth (29), and an output element (4) that is designed as a ring gear and has internal teeth (30) that partially mesh with the external teeth (29). The flexible transmission element (26) is pot-shaped, and is coupled in a torque-transmitting manner to the drive element (2) radially inside the outer teeth (29).