Harmonic Drive Flanged Bushing Press Joint for Torque Slip Control
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Solution Overview
Problem
Existing harmonic drives face challenges in achieving a compact, production-friendly construction with high operational reliability, particularly in maintaining a secure connection that compensates for manufacturing tolerances and allows for efficient torque transmission while preventing relative rotating under low torque and allowing for slight slipping under overload.
Innovation Solution
A harmonic drive design featuring a deformable flanged bushing with a wave-shaped profiling that forms a positively locking press joint with the housing, utilizing a thin-walled bushing section for frictional locking and a wave-shaped counter-contour for elastic design, ensuring efficient assembly, low space requirements, and high fatigue strength, with discrete contact points for torque transmission without backlash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a screwed connection is used to fasten the flanged bushing to the housing, then the connection is secure and reliable, but the assembly process becomes time-consuming and complex
Solution Approach 1:
The invention extracts and eliminates the screwed connection from the assembly, replacing it with a press-fit connection between the bushing section and the housing component. This removes the time-consuming screw fastening process while maintaining a secure connection through the positively locking press joint.
Solution Approach 2:
The invention merges the fastening function with the structural connection by designing the bushing section to be directly press-fitted into the housing component. The connection structure itself provides both structural support and fastening, eliminating the need for separate fastening elements like screws.
2Volume of moving object
If a thin-walled flanged bushing is used for the drive element, then the space requirement is reduced and the design becomes more compact, but the torque transmission capability under low torque conditions becomes insufficient
Solution Approach 1:
The invention introduces a wave-shaped profiling that dynamically adapts the connection characteristics. Under low torque, the wave shape allows frictional locking to prevent relative rotating. Under overload, the wave shape enables controlled macroscopic slipping while preventing catastrophic failure.
Solution Approach 2:
The invention creates a composite connection system combining frictional locking (for low torque prevention) and positively locking wave shape (for overload protection). This composite approach allows the thin-walled bushing to handle both low torque transmission and overload conditions effectively.
3Productivity
If a rigid connection is used between the bushing and housing, then the torque transmission is efficient, but the manufacturing tolerances cannot be compensated and the risk of damage increases
Solution Approach 1:
The invention changes the connection parameter from rigid to elastic by introducing the wave-shaped profiling. This allows the connection to deform elastically within certain limits, compensating for manufacturing tolerances while maintaining efficient torque transmission through the wave shape's mechanical interlocking.
4Reliability
If a positively locking connection is used to prevent relative rotating, then the connection is secure under low torque, but the ability to allow controlled slipping under overload is reduced
Solution Approach 1:
The wave-shaped profiling creates a dynamic connection that transitions from frictional locking under low torque to controlled macroscopic slipping under overload. The connection adapts its behavior based on the applied torque, providing security when needed and protection when overloaded.
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 design provides a compact, reliable, and efficient harmonic drive mechanism that compensates for manufacturing tolerances, prevents relative rotating under low torque, and allows for controlled slipping under overload, ensuring consistent performance and durability.
Implementation Method 1
relative rotating between the thin-walled flanged bushing and the two elements which are fixed on the housing is prevented first of all by way of a frictionally locking connection
Implementation Method 2
manufacturing tolerances of solid components which are fixed on the housing are compensated for by way of the elasticity which exists between the wave peaks of the thin-walled bushing section
Data Source
AI summary
A harmonic drive including a housing component (4) and a drive element (18) which is held on the housing component, can be deformed by a wave generator (14), is in the form of a flanged bushing and has a toothing region (17) having a cylindrical basic shape and a disc section (19) which adjoins the toothing region (17). Adjoining the disc section (19) there is a bushing section (20) which is concentric to the toothing region (17), overlaps the latter in the axial direction and is held interlockingly between a cylindrical edge section (21), which is thick-walled in comparison with the bushing section (20), of the housing component (4) and an intrinsically rigid component (22) which is likewise solid in comparison with the flanged bushing (18).