Elastomeric Toothed Belt Strain Wave Gear for High Torque
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Solution Overview
Problem
Existing strain wave gears face challenges in producing a wave generator that is easy to manufacture and can reliably transmit high torques, particularly in small dimensions, which requires complex manufacturing processes for deformable metal sleeves.
Innovation Solution
Designing an elastically deformable force-transmitting ring element as an elastomeric toothed belt with external teeth, coupled with a second ring gear, allowing for a simpler and more cost-effective production method, and incorporating a rotating planetary gear carrier with unprofiled planetary gears for precise guidance and high torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a deformable metal sleeve is used as the force-transmitting ring element, then high torque transmission is achieved, but manufacturing complexity and costs increase significantly
Solution Approach 1:
The patent changes the material parameter from metal to elastomer, transforming the force-transmitting ring element from a rigid metal sleeve to a flexible elastomeric component. This material substitution enables torque transmission through elastic deformation rather than rigid structural deformation, significantly simplifying manufacturing processes while maintaining torque transmission capability
Solution Approach 2:
The patent employs composite construction by combining the elastomeric force-transmitting ring element with rigid toothed belt components and planetary gears. This composite approach allows the elastomer to handle flexible deformation and torque transmission, while the rigid components provide structural support and precise gear engagement, resolving the contradiction between torque capability and manufacturing ease
2Productivity
If the pitch circle diameter of the external teeth is smaller than that of the internal teeth, then high transmission ratio is achieved, but the number of teeth decreases
Solution Approach 1:
The patent introduces dynamic deformation of the elastomeric ring element, which allows the effective number of engaged teeth to vary during operation. As the elastomer deforms elastically under load, teeth engage and disengage dynamically, enabling high transmission ratios without requiring a fixed reduction in tooth count. This dynamic behavior resolves the contradiction between transmission ratio and tooth quantity
3Ease of manufacture
If unprofiled planetary gears are used in the wave generator, then manufacturing is simplified, but precise guidance must be maintained
Solution Approach 1:
The patent introduces the elastomeric ring element as an intermediary between the unprofiled planetary gears and the toothed belt. This elastomeric intermediary compensates for the lack of precise gear profiles by providing elastic compliance and self-centering, allowing unprofiled gears to achieve precise guidance through the mediating effect of the deformable elastomer rather than relying solely on precise gear 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 strain wave gears with high transmission ratios and consistently high efficiencies, reducing manufacturing complexity and costs while maintaining precise and smooth operation.
Implementation Method 1
a rotating wave generator (4) which radially deforms by a rotating radial force an elastically deformable force-transmitting ring element (5; 25)
Implementation Method 2
unprofiled planetary gears (14, 15) on a rolling side, which roll on the power-transmitting element with a rolling diameter that is larger than the calculated inner diameter
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Wave gear with a rotating wave generator that produces a rotating radial force shaft which radially deforms a force-transmitting, elastic ring element provided with external teeth, and with a first ring gear provided with internal teeth, wherein the pitch circle diameter of the external teeth of the force-transmitting ring element is smaller than the pitch circle diameter of the internal teeth of the first ring gear and the external teeth of the force-transmitting ring element engage with corresponding partial areas of the internal teeth of the first ring gear in at least two tooth engagement areas deformed by the wave generator and displaced circumferentially over the periphery of the first ring gear, wherein the elastically deformable force-transmitting ring element is designed as an elastomeric toothed belt.wherein a second ring gear with internal teeth is provided and the pitch circle diameter of the external teeth of the power-transmitting ring element designed as an elastomeric toothed belt is also smaller than the pitch circle diameter of the internal teeth of the second ring gear, wherein the elastomeric toothed belt engages equally with partial areas of the internal teeth of the second ring gear in the circumferentially displaced tooth engagement areas.