Countershaft Powershift Transmission With Fewer Clutches
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Solution Overview
Problem
Existing powershift transmissions for agricultural machinery are complex in production and lack flexibility in operating modes, particularly not allowing a creeper gear mode, and require a large number of clutches, which complicates their design and increases size.
Innovation Solution
A powershift transmission design with two shift groups and a countershaft, allowing for various gear pair configurations and switching states, enabling a large number of gear variants with minimal structural changes, reducing the need for clutches and maintaining a compact size by using a countershaft with at least two clutches, and integrating a reversing unit for reverse travel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a two-stage power shift transmission with planetary gears and clutches is used, then the transmission can be operated in various operating modes (through-drive mode, reduction mode, reversing mode), but the production technology becomes complex and further operating modes like creeper gear mode cannot be added
Solution Approach 1:
The patent applies universality by designing a transmission system where a single modular architecture can perform multiple functions. The planetary gear set is configured to provide through-drive mode, reduction mode, and reversing mode through different engagement states of the same components, without requiring separate dedicated mechanisms for each mode. This allows the transmission to be versatile while avoiding the complexity of having separate systems for each operating mode.
Solution Approach 2:
The patent segments the transmission system into modular components: a planetary gear set, a first clutch for engaging/disengaging the planetary gear, and a second clutch for the reversing unit. This segmentation allows each component to be independently designed and controlled, simplifying the overall production technology while maintaining the ability to achieve multiple operating modes through coordinated engagement of these discrete modules.
2Adaptability or versatility
If multiple clutches are used to enable various gear pair configurations and switching states, then a large number of gear variants can be achieved, but the number of clutches increases which complicates design and increases size
Solution Approach 1:
The patent makes the planetary gear set multi-functional by using a single clutch mechanism to achieve multiple gear variants. The first clutch can engage or disengage the planetary gear to provide different transmission ratios, and the second clutch controls the reversing unit. This universal design allows the same components to provide multiple gear variants (including creeper gear mode) without requiring a separate clutch for each gear change, thereby reducing the total number of clutches needed.
Solution Approach 2:
The patent merges the functions of multiple potential clutch mechanisms into a streamlined system. Instead of having separate clutches for each gear pair configuration, the design combines the gear shifting function and reversing function into two clutch-controlled modules. This merging reduces the number of clutches from what would traditionally be required for each individual gear variant down to just two clutches that control multiple operating modes through their engagement and disengagement states.
3Adaptability or versatility
If traditional powershift transmission designs are used, then through-drive mode and reduction mode are available, but creeper gear mode cannot be implemented
Solution Approach 1:
The patent achieves universality by designing the planetary gear set and clutch system to provide three distinct operating modes: through-drive mode (clutch disengaged, planetary gear overrunning), reduction mode (clutch engaged, planetary gear rolling around brake-locked sun gear), and creeper gear mode (additional engagement state of the same components). This multi-functional design allows creeper gear mode to be implemented without adding separate dedicated mechanisms, as the existing universal components can be configured to provide this additional mode through different engagement states.
Data Source
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AI summary
The invention relates to a power shift transmission for an agricultural machine comprising a gearbox housing, an input shaft and an output shaft unit, wherein the input shaft and the output shaft unit extend at least partially within the gearbox housing, wherein a countershaft is arranged parallel offset between the input shaft and the output shaft unit within the gearbox housing, wherein the input shaft and the countershaft are connected to each other via a pre-shift group and the countershaft and the output shaft unit via a post-shift group.