Transfer Case Locking Sleeve and Plate Clutch Torque Coupling
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Solution Overview
Problem
Current transfer cases do not effectively positively couple the primary output shaft to the secondary output shaft for torque transfer, limiting the efficiency of power distribution in four-wheel drive modes.
Innovation Solution
A transfer case with a secondary torque transfer mechanism that includes a plate clutch and a locking sleeve, allowing for both friction coupling and positive coupling between the primary and secondary output shafts, enabling efficient torque transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a friction coupling mechanism (plate clutch) is used to transfer torque between the primary and secondary output shafts, then torque transfer is possible, but the coupling is not positive and torque transfer efficiency is limited
Solution Approach 1:
The coupling mechanism is segmented into two distinct components: a friction coupling element (plate clutch) for selective torque transfer and a positive locking element (locking sleeve with dogs) for secure engagement. This segmentation allows each component to perform its specific function optimally while working together to resolve the contradiction between reliable torque transfer and acceptable complexity.
Solution Approach 2:
The locking sleeve acts as an intermediary element that bridges the primary and secondary output shafts. It provides the positive coupling mechanism that directly addresses the limitation of friction-based torque transfer, enabling reliable and efficient torque transmission when four-wheel drive mode is engaged.
2Reliability
If only a friction coupling mechanism is used, then the device structure is simpler, but positive coupling between the primary and secondary output shafts is not achieved
Solution Approach 1:
The invention merges the friction coupling mechanism and the positive locking mechanism into a single integrated secondary torque transfer mechanism. The locking sleeve is positioned within the plate clutch assembly, combining both coupling approaches to achieve reliable positive coupling while maintaining a compact and manageable device structure.
Solution Approach 2:
The secondary torque transfer mechanism is designed to provide multiple functions: friction-based torque transfer for smooth engagement and positive locking for secure connection. This multi-functionality ensures reliable positive coupling between the output shafts while managing the overall device complexity through integrated design.
3Productivity
If a locking mechanism is added to provide positive coupling, then torque transfer efficiency improves, but the device complexity increases
Solution Approach 1:
The locking sleeve and its positive locking elements are nested within the existing plate clutch assembly. This nesting approach allows the addition of positive coupling capability without significantly increasing the overall device complexity, as the locking mechanism utilizes the same spatial envelope and structural framework as the friction coupling mechanism.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances torque transfer efficiency between the primary and secondary output shafts, improving power distribution in four-wheel drive modes and providing a reliable coupling mechanism.
Implementation Method 1
The apply plate is coupled to the primary output shaft to rotate therewith and is configured to compress the interleaved plates to selectively form a friction coupling between the primary output shaft and the secondary output shaft
Implementation Method 2
The locking sleeve is non-selectively coupled to one of the housing or the apply plate to rotate therewith and is configured to selectively couple to the other of the housing or the apply plate to form a positive coupling between the primary output shaft and the secondary output shaft
Data Source
AI summary
A transfer case includes a primary output shaft, and a secondary output selectively coupleable to the primary output shaft with a secondary torque transfer mechanism. The secondary torque transfer mechanism comprises a plate clutch and a locking sleeve. The plate clutch includes a housing coupled to the secondary output shaft, a plurality of interleaved plates alternatingly coupled to the primary output shaft and the housing, and an apply plate coupled to the primary output shaft and being configured to compress the interleaved plates to selectively form a friction coupling between the primary output shaft and the secondary output shaft. The locking sleeve is non-selectively coupled to one of the housing or the apply plate to rotate therewith, and is selectively coupleable to the other of the housing or the apply plate to form a positive coupling between the primary output shaft and the secondary output shaft.