Strain Wave Gear Assembly With Floating Wave Generator Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing strain wave gear systems face challenges in efficient installation, sealing, and lubrication, leading to potential misalignment, radial loading issues, and difficulties in ensuring proper grease application.
Innovation Solution
The proposed strain wave gear system incorporates a ring gear, a wave generator, and a flexspline with a non-circular shape, along with a sealing system using a housing and cap with a protrusion and cavity to ensure consistent sealant application, and a lubricating system with a plunger to precisely deliver grease to bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ball bearings are used to constrain the wave generator, then the manufacturer can properly position the wave generator, but the bearings become over-constrained and experience undesirable radial loads due to manufacturing tolerances and eccentricities
Solution Approach 1:
The patent removes the ball bearings that were previously used to constrain the wave generator radially. Instead, the wave generator is constrained only axially by the input assembly, allowing it to float radially and accommodate manufacturing tolerances without creating excessive radial loads on bearing components.
Solution Approach 2:
The wave generator is designed to float radially within the flexspline, transitioning from a statically constrained position to a dynamically adaptable position that naturally accommodates eccentricities and manufacturing variations, thereby reducing harmful radial loads.
2Ease of manufacture
If the wave generator is attached to the input as an assembly, then the system can be installed, but the input requires custom modifications and the end user bears responsibility for proper positioning
Solution Approach 1:
The wave generator is pre-positioned and constrained within the flexspline assembly during manufacturing, so that when the complete assembly is installed, the critical positioning has already been accomplished by the manufacturer rather than requiring precise user installation.
Solution Approach 2:
The wave generator and flexspline are combined into a single pre-assembled unit with integrated positioning features, eliminating the need for separate positioning steps and custom input modifications while ensuring proper alignment from the factory.
3Reliability
If sealant is applied in traditional strain wave gear systems, then sealing is achieved, but consistent application is difficult and improper application can harm the system
Solution Approach 1:
Sealant is pre-applied to the mating surfaces of the cap and housing before final assembly, ensuring consistent coverage and proper positioning. This preliminary application eliminates the difficulty of applying sealant after components are assembled and ensures reliable sealing from the start.
Solution Approach 2:
The patent introduces specific structural features (such as sealant retention grooves or channels) that act as intermediaries to guide and hold the sealant in the correct position, making application easier and ensuring consistent, proper sealing without requiring highly skilled manual application.
4Reliability
If grease is applied to bearings in traditional systems, then lubrication is provided, but ensuring proper grease application is difficult and can be time-consuming
Solution Approach 1:
Grease is pre-applied to the bearing surfaces during manufacturing, so that when the strain wave gear assembly is installed, the bearings are already lubricated and ready for operation. This eliminates the time-consuming step of manual grease application by the installer.
Solution Approach 2:
The bearing design includes integrated grease retention features or pre-filled grease cartridges that allow the bearing to self-lubricate upon assembly, eliminating the need for external grease application and ensuring proper lubrication without requiring user intervention or time investment.
Data Source
AI summary
A strain wave gear system (10) includes first and second sets of ball bearings (80, 82) located intermediate a flange (84) and a retainer plate (88) rotatable with an output (54) and a radially oriented flat disc (74) of the input including strain relief (76). Strain relief (76) is a helical slot in a coupling (70) located radially within the wave generator (94) and the ring gear (22). The ring gear (22) is sealed by a sealing system including sealant (42) forced by a protrusion (34) of the cap (24) entering into a cavity (36) through a channel (40) into a relief volume (38) of the housing (12). The bearing (48) rotatably mounting the housing (12) to the output (54) is lubricated by a lubricating system including plungers (110) threadably received in axial bores (102) intersecting with radial bores (104) in communication with radial holes (47) of the bearing (48).