CVT Case Rib Layout for Gear Noise and Weight Reduction
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Solution Overview
Problem
Existing driving force transmission apparatuses face challenges in weight reduction while maintaining structural integrity and noise/vibration suppression, as conventional rib configurations either increase weight or require additional components for reinforcement and noise/vibration suppression.
Innovation Solution
A driving force transmission apparatus with a case design featuring an axial rib that extends linearly from the side cover to the housing, positioned adjacent to the gears and oil pump, connecting both fastening points and incorporating a hollow structure to suppress meshing reaction forces and vibrations, thereby reducing weight and enhancing rigidity and noise/vibration suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a grid-like rib is provided over the entire surface of the outer wall, then the transmission case gains reinforcement and noise/vibration suppression, but the transmission case weighs more
Solution Approach 1:
The patent applies local quality by providing a rib structure only at specific locations where reinforcement is needed (adjacent to gears and oil pump) rather than covering the entire outer wall surface. This localized approach maintains structural integrity at critical areas while eliminating unnecessary material elsewhere, thereby reducing overall weight.
Solution Approach 2:
The rib structure is segmented into specific functional zones: one rib adjacent to the gears for suppressing meshing reaction forces, and another rib adjacent to the oil pump for suppressing vibrations. This segmentation allows each rib to perform its specific function efficiently without requiring a comprehensive grid-like coverage, thus reducing material usage and weight.
2Object-generated harmful factors
If a grid-like rib is provided over the entire surface of the outer wall, then noise and vibration suppression is improved, but the transmission case weighs more
Solution Approach 1:
The patent places rib structures only at locations where noise and vibration generation occurs - specifically adjacent to the gears for meshing noise suppression and adjacent to the oil pump for vibration suppression. This localized noise and vibration control eliminates the need for comprehensive surface coverage, thereby reducing weight while maintaining effectiveness.
Solution Approach 2:
The rib structures are positioned to convert harmful meshing reaction forces and vibrations into beneficial structural support. By placing ribs at these specific locations, the harmful forces are suppressed and redirected through the rib structure, transforming potential damage into structural reinforcement without requiring additional weight.
3Strength
If additional ribs are added for reinforcement and noise/vibration suppression, then structural integrity is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple functions into the rib structure: reinforcement, noise suppression, and vibration suppression are all achieved through the same rib elements. The first rib serves both to reinforce the structure and suppress gear meshing noise, while the second rib simultaneously reinforces and suppresses oil pump vibrations. This merging eliminates the need for separate components, reducing device complexity.
Solution Approach 2:
The rib structure is designed with multi-functionality, serving as both a reinforcement element and a noise/vibration suppression element. Each rib is positioned to perform multiple roles: structural support, noise reduction, and vibration damping, thereby eliminating the need for additional specialized components and simplifying the overall device complexity.
Data Source
AI summary
The continuously variable transmission includes a transmission case having a side cover, a housing, and a case sandwiched between the side cover and the housing, an oil pump disposed in the transmission case, and a pair of gears disposed in the transmission case. An axial rib having a linear shape extending from the side cover toward the housing is formed on an outer wall surface of the case at a position adjacent to the pair of gears. The axial rib is positioned on a straight line extending from the oil pump in the vertical direction and is locally positioned at a position where the meshing reaction force of the pair of gears is suppressed.