Torque Converter Hub Chamfer and Gear Extensions for Friction Reduction
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Solution Overview
Problem
The existing assembly process of a torque converter and transmission in automotive powertrains faces challenges due to friction between the torque converter and auxiliary gear during indexing, making it difficult to align and mount the auxiliary gear correctly.
Innovation Solution
The implementation of a hub with a chamfered edge and a gear with extensions that contact only during indexing, reducing friction by minimizing surface contact and allowing for precise alignment before sliding the hub into the gear's axial opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the torque converter is lowered on the auxiliary gear such that the weight of the torque converter is bearing on the auxiliary gear during indexing, then the torque converter can be positioned on the transmission, but friction is produced between the torque converter and auxiliary gear causing the auxiliary gear to rotate with the torque converter, making alignment and mounting more difficult
Solution Approach 1:
The auxiliary gear is segmented into two functional zones: a reduced-contact-area region that contacts the torque converter hub during indexing, and a full-contact region that engages with the hub after alignment. This segmentation allows the gear to provide sufficient support during positioning while minimizing friction that would cause unwanted rotation.
Solution Approach 2:
The auxiliary gear has non-uniform contact surface properties: the peripheral portion has a reduced contact area with the hub to minimize friction during indexing, while the central portion maintains full contact capability for secure mounting after alignment. This local quality variation resolves the contradiction between needing support and avoiding friction-induced rotation.
2Stability of the object's composition
If the auxiliary gear has full surface contact with the hub during indexing, then stable support is provided, but increased friction causes the gear to rotate with the torque converter, complicating alignment
Solution Approach 1:
The contact interface is segmented into an active support zone (reduced contact area) and a passive engagement zone (full contact capability). During indexing, only the active zone engages, providing minimal stable support while allowing precise rotational alignment. After alignment, the full contact capability ensures secure mounting.
Solution Approach 2:
Instead of full surface contact, only a partial reduced-contact-area portion of the auxiliary gear contacts the hub during indexing. This partial action provides just enough stability to prevent excessive play while minimizing friction to enable precise alignment, avoiding the over-constraint that would hinder alignment precision.
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 reduces friction and facilitates easier alignment and mounting of the auxiliary gear, improving the assembly process by minimizing surface contact and ensuring accurate alignment.
Implementation Method 1
friction is reduced between the torque converter and auxiliary gear during installation of the auxiliary gear to the hub of the torque converter impeller
Data Source
AI summary
An automatic transmission assembly includes a torque converter drivably engaged with a transmission. The torque converter has an impeller with a hub. The hub has an exterior surface, a hub end face, and a first chamfered edge between the exterior surface and the hub end face. A gear has an axial opening, a gear end face, and a second chamfered edge between the axial opening and the gear end face. First and second extensions extend from the second chamfered edge. The first and second extensions extend in a direction normal to the second chamfered edge. During indexing of the torque converter, the first and second extensions contact the first chamfered edge.