Steel Inner Drum Structure to Prevent Spline Stripping
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Solution Overview
Problem
Existing inner drums in automobile transmissions, typically made of aluminum, suffer from deformation and spline stripping when metal parts contact them, limiting their ability to accommodate multiple clutches effectively.
Innovation Solution
A steel inner drum design featuring a coupling part with internal splines, an annular trough, circular wall appendages with rib structures and slots for snap rings, and a lip structure that allows for enhanced engagement and stability, enabling the accommodation of additional clutches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If aluminum material is used for the inner drum, then weight is reduced, but deformation and spline stripping occur when metal parts contact
Solution Approach 1:
The patent changes the material parameter from aluminum to steel, fundamentally altering the mechanical properties of the inner drum. This material substitution increases strength and hardness, preventing deformation and spline stripping while maintaining the drum's structural function in the transmission system.
Solution Approach 2:
The inner drum employs a composite structure combining steel material with specific geometric features including splines, appendages, slots, and a lip structure. This composite design integrates the high strength of steel with functional elements that accommodate multiple clutches, resolving the contradiction between weight reduction and reliability.
2Ease of manufacture
If the inner drum design is simplified, then manufacturing is easier, but the ability to accommodate multiple clutches is limited
Solution Approach 1:
The inner drum is segmented into distinct functional elements: a coupling part with splines, an annular trough, a circular wall with multiple appendages, slots for snap rings, and a lip structure. Each segment serves a specific function in accommodating clutches, allowing the drum to handle multiple clutches while maintaining manufacturability through modular design features.
Solution Approach 2:
The inner drum design incorporates universal features that enable it to accommodate multiple different clutch types. The circular wall with evenly spaced appendages and slots provides a standardized interface that can engage various clutch configurations, making the single drum design adaptable to multiple clutch arrangements without requiring complex customizations.
3Productivity
If more clutches are added to the inner drum, then transmission functionality is improved, but structural complexity increases
Solution Approach 1:
The patent utilizes the radial dimension by extending appendages outward from the circular wall to create engagement surfaces for clutch plates. This dimensional approach allows multiple clutches to be accommodated in the radial space around the drum's circumference, increasing clutch capacity without proportionally increasing axial or circumferential complexity.
Solution Approach 2:
The inner drum structure nests multiple functional elements within a compact configuration: splines are nested within the coupling part, appendages extend from the circular wall, slots are positioned within the appendages for snap rings, and the lip structure is integrated between the circular wall and annular trough. This nesting allows multiple clutches to be accommodated in a space-efficient manner.
Data Source
AI summary
An inner drum that includes a coupling part having an external surface and an internal surface, wherein the internal surface contains splines. An annular trough is engaged to the exterior surface of the coupling part. A circular wall contains a plurality of appendages extending upward from the circular wall. At least one slot is disposed within the appendages for receiving a snap ring.