Single Shift Drum Transmission for Compact Gear Selection
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Solution Overview
Problem
Existing transmissions with first and second shift clutches for engine power transmission are large and costly due to the use of multiple change drums and step motors for gear shifting, leading to increased complexity and size.
Innovation Solution
A transmission design that uses a single shift drum with guide portions to select gear steps in both the first and second shifting parts, where the shift elements also serve as shifters, reducing the need for additional shifters and allowing gear shifts between selected steps by switching transmission paths with the first and second shift clutches, and employing an electric motor for the selection mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple change drums and step motors are used for each shift clutch, then gear shifting control is achieved, but the transmission size and cost increase
Solution Approach 1:
The patent combines the functions of multiple change drums into a single change drum. The first and second shift clutches share common guide portions on this single drum, eliminating the need for separate change drums for each clutch. This merging reduces the overall transmission size while maintaining the ability to control both shift operations independently through the shared drum's guide portions.
Solution Approach 2:
The single change drum serves multiple functions by providing guide portions for both the first shifter associated with the first shift clutch and the second shifter associated with the second shift clutch. This universal component performs what previously required separate dedicated components, reducing complexity and size while enabling coordinated control of multiple shifting operations.
2Ease of operation
If multiple change drums and step motors are used for each shift clutch, then gear shifting control is achieved, but manufacturing cost increases
Solution Approach 1:
By merging multiple change drums into a single change drum with integrated guide portions, the patent reduces the number of components that need to be manufactured, assembled, and inventoried. This consolidation lowers manufacturing costs through reduced material usage, simplified assembly processes, and decreased production complexity, while still providing the necessary control functions for multiple shift clutches.
Solution Approach 2:
The universal change drum design allows a single component to perform multiple shifting control functions, reducing the total bill of materials and manufacturing complexity. This multi-functional approach eliminates the need to manufacture separate change drums for each shift clutch, thereby reducing overall manufacturing costs while maintaining full gear shifting control capability.
3Adaptability or versatility
If separate shift drums are used for first and second clutches, then independent gear step selection is achieved, but device complexity increases
Solution Approach 1:
The patent merges the functions of separate shift drums into a single change drum that contains guide portions for both shifters. This consolidation reduces device complexity by eliminating redundant components while maintaining the ability to independently select gear steps for both the first and second clutches through the shared drum's differently positioned guide portions.
Solution Approach 2:
The single change drum is designed as a universal component that provides independent gear step selection for multiple clutches through its multiple guide portions. Each guide portion can be positioned to engage with the corresponding shifter, enabling independent control of each shift clutch while using a single unified component instead of multiple separate drums.
Data Source
AI summary
A transmission includes a first shifting part and a second shifting part which shift power of an internal combustion engine, a first shift clutch transmitting and interrupting the power to the first shifting part, and a second shift clutch transmitting and interrupting the power to the second shifting part, and a selection mechanism which selects gear steps. The selection mechanism includes three shifters that are respectively guided by cam grooves of a single shift drum through shift forks. The shifters can be respectively moved to selection positions where the gear steps are selected and to neutral positions where the gear steps are not selected in the first shifting part and the second shifting part. The cam grooves guide the shifters to the selection positions in each of the first shifting part and the second shifting part for each of predetermined rotational positions of the shift drum.