Strain Wave Gear Rolling Contact for Axial Rattle Suppression
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Solution Overview
Problem
Existing strain wave gearing mechanisms experience axial-direction displacement and high friction loss due to sliding contact with regulating members, which affects the efficiency of the gear movement.
Innovation Solution
The strain wave gearing incorporates a radially flexible cylindrical externally toothed gear with first and second internally toothed gears, a wave generator, and regulating parts with raceway grooves and rolling elements to facilitate rolling contact instead of sliding, reducing friction loss and axial-direction movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a regulating member (plate, retaining ring) is arranged to regulate axial-direction movement of the externally toothed gear, then axial-direction movement is regulated, but axial-direction displacement still occurs and friction loss is high due to sliding contact
Solution Approach 1:
The patent replaces the sliding contact mechanism with a rolling contact mechanism by introducing rolling elements (balls or rollers) between the externally toothed gear and the regulating members. This substitution transforms the frictional sliding interaction into rolling interaction, dramatically reducing friction loss while maintaining effective axial movement regulation.
Solution Approach 2:
The patent introduces rolling elements as intermediary components between the externally toothed gear and the regulating members (fixed-side and rotating-side members). These rolling elements act as mediators that transmit the regulatory function while minimizing direct sliding contact, thereby reducing friction loss.
2Reliability
If a regulating member is arranged to regulate axial-direction movement of the externally toothed gear, then axial-direction movement is regulated, but axial-direction displacement still occurs
Solution Approach 1:
The patent replaces the sliding contact mechanism with a rolling contact mechanism by introducing rolling elements (balls or rollers) between the externally toothed gear and the regulating members. This substitution transforms the frictional sliding interaction into rolling interaction, dramatically reducing friction loss while maintaining effective axial movement regulation.
Solution Approach 2:
The patent changes the contact mode parameter from sliding to rolling by introducing rolling elements. This parameter change fundamentally alters the interaction between the gear and regulating members, eliminating axial displacement while maintaining regulation functionality.
3Reliability
If the externally toothed gear is configured as a double helical gear, then axial-direction movement is regulated, but device complexity increases
Solution Approach 1:
The patent segments the regulating mechanism into separate components: fixed-side regulating members, rotating-side regulating members, and rolling elements. This segmentation allows each component to perform its specific function independently, achieving axial movement regulation without requiring the complex double helical gear configuration.
Solution Approach 2:
The patent introduces rolling elements as intermediary components between the externally toothed gear and the regulating members (fixed-side and rotating-side members). These rolling elements act as mediators that transmit the regulatory function while minimizing direct sliding contact, thereby reducing friction loss.
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 configuration significantly reduces friction loss and suppresses axial-direction movement, enhancing the efficiency of the strain wave gearing by ensuring rolling contact and applying pressure in the axial direction, thereby preventing thrust force generation.
Implementation Method 1
a plurality of first rolling elements sandwiched between the first raceway groove and the fixed-side raceway groove in a state that allows rolling... a plurality of second rolling elements sandwiched between the second raceway groove and the rotating-side raceway groove in a state that allows rolling
Implementation Method 2
a radially flexible cylindrical externally toothed gear... a wave generator that causes the externally toothed gear to flex in a radial direction
Data Source
AI summary
In a strain wave gearing, in order to regulate axial-direction movement of an externally toothed gear thereof, first balls are directly interposed between a first annular end surface and a device housing, whereby the first annular end surface and the device housing are in rolling contact with one another. Similarly, second balls, are directly interposed between a second annular end surface and an output shaft, whereby the second annular end surface and the output shaft are in rolling contact with one another. No contact occurs other than rolling contact of contact portions. Additionally, pressure is applied in the axial direction to the portions that make rolling contact, and axial-direction rattling is eliminated, whereby axial-direction movement of the externally toothed gear is reliably suppressed, and generation of high thrust force is prevented.