Modular Tractor Transmission Module CVT Powershift Configuration
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Solution Overview
Problem
Existing modular transmission systems for agricultural tractors are not adequately suited for all agricultural applications, as they either lack versatility or require extensive reconfiguration, leading to increased factory lead times and limited customer choices.
Innovation Solution
A modular transmission module with an epicyclic gearing system that can be selectively configured between continuous variable transmission (CVT) and multi-ratio powershift transmission arrangements, utilizing a universal end flange with interchangeable shaft supports and hydraulically operated clutches to accommodate different power input and output ratios, allowing for a high percentage of common parts and reduced assembly time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a modular transmission system is used to provide customer choice and reduce lead times, then factory lead time is reduced and customer choice is enhanced, but the transmission must be designed to accommodate multiple transmission types (CVT and powershift) which increases design complexity
Solution Approach 1:
The epicyclic gear unit is designed as a universal module that can function in multiple transmission configurations. The same basic epicyclic module serves both CVT and powershift transmission types by changing only the connection configuration between the input shaft and the third gear element, allowing one design to fulfill multiple functions and reduce overall system complexity
Solution Approach 2:
The transmission system is divided into separable functional modules: the common epicyclic gear unit and the variable transmission type components (CVT mechanism or powershift clutches). This segmentation allows the common parts to be pre-assembled and stocked, reducing factory lead time while the specific transmission type can be configured later based on customer requirements
2Ease of manufacture
If a single modular module is designed to accommodate both CVT and powershift arrangements, then the percentage of common parts increases and manufacturing efficiency improves, but the module must include redundant components which increases the device complexity
Solution Approach 1:
The universal end flange is designed with multiple shaft support configurations that can accommodate different transmission arrangements. The same physical flange structure serves multiple functions by supporting different shaft configurations depending on whether CVT or powershift is implemented, reducing the need for separate components for each transmission type
Solution Approach 2:
The module includes redundant shaft supports in the end flange that are activated locally depending on the transmission type. For example, the end flange may have a redundant shaft support that is used in CVT arrangement but not in powershift arrangement, allowing the same component to adapt to different local requirements without requiring complete redesign
3Adaptability or versatility
If the epicyclic gear unit is designed with three gear elements for selective configuration, then versatility between CVT and powershift arrangements is achieved, but the gear unit complexity increases compared to traditional single-configuration epicyclics
Solution Approach 1:
The epicyclic gear unit is designed with dynamic configurability through the third gear element that can be selectively connected to different components depending on the transmission type. In CVT arrangement, the third gear element connects to the variable ratio mechanism, while in powershift arrangement, it connects to clutch mechanisms, allowing the same gear unit structure to adapt dynamically to different operational requirements
Data Source
AI summary
There is provided transmission module (10) for a tractor which is selectively configurable between a CVT arrangement and a multi-ratio powershift transmission arrangement. The module comprises an epicyclic unit (13) in which a first gear element of the epicyclic is driven mechanically from the input shaft (11) and a second gear element of the epicyclic acts as an output of the transmission module. By simply connecting either a CVT unit (24) or a pair of clutches (80) between the input shaft and a third gear element the module (10) can be converted to the desired transmission arrangement. This delivers benefits in a factory for example whereby a large proportion of the assembly can be completed before tailoring the transmission to a customers requirements, thus reducing lead times on delivery.