Switchable i-brake Clutch with Transition Mode
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Solution Overview
Problem
Current clutch assemblies for hybrid transmission applications lack a 'change of mind' mode that allows for clutch engagement adjustments without additional signals, leading to inefficiencies in transition phases.
Innovation Solution
The clutch assembly incorporates an actuation assembly with struts and pawls that enable a transition mode by rotating struts within pockets to achieve partial or full engagement with the inner ring, allowing for freewheel, transition, and locked modes without additional signals, utilizing an actuation plate to displace axially and rotate struts to control pawl engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a clutch assembly uses traditional binary engagement (fully engaged or fully disengaged), then the structure is simple and reliable, but it lacks flexibility for transition modes and cannot achieve 'change of mind' adjustments
Solution Approach 1:
The clutch assembly is segmented into multiple functional components: outer ring, inner ring, multiple struts (first strut, second strut), and multiple pawls (first pawl, second pawl). Each component has a specific function in controlling engagement states. The segmentation allows independent control of different engagement phases, enabling transition modes between fully engaged and fully disengaged states.
Solution Approach 2:
The clutch assembly incorporates dynamic elements including rotatable struts within pockets, spring-biased pawls, and movable actuation plates. The struts can rotate to different positions (first position, second position, third position) to control pawl engagement dynamically. The spring biasing allows pawls to automatically engage or disengage based on rotational direction and applied forces, providing adaptive transition modes.
2Adaptability or versatility
If the clutch assembly includes multiple struts and pawls for transition mode control, then engagement flexibility is improved, but the number of components and structural complexity increases
Solution Approach 1:
Multiple struts and pawls are integrated within a single outer ring structure that contains multiple pockets. The actuation plates serve dual purposes by controlling multiple struts simultaneously. The inner ring with circumferential teeth serves as a common engagement surface for multiple pawls. This merging reduces the number of separate assemblies while maintaining transition mode functionality.
Solution Approach 2:
The struts serve multiple functions: they control pawl engagement, provide mechanical advantage for actuation, and can be positioned in different states (first position for disengagement, second position for transition, third position for full engagement). The pawls serve both as engagement elements and as indicators of clutch state. The actuation plates control multiple struts and can operate in different axial directions, providing multi-functionality with reduced component count.
3Ease of operation
If the clutch assembly uses spring-biased pawls for automatic engagement, then ease of operation is improved, but the force required for actuation increases
Solution Approach 1:
The springs are pre-loaded to bias the pawls toward the engaged position before actuation occurs. This preliminary action means that once the actuation plate moves the strut to the appropriate position, the pawl automatically engages with the teeth without requiring additional actuation force. The spring stores energy that is released to drive the engagement, reducing the force needed from the actuator.
Solution Approach 2:
The spring bias provides excessive engagement force to ensure positive engagement of the pawl with the teeth. This excessive action guarantees reliable engagement but requires the actuation system to overcome the spring force during disengagement. The design accepts this trade-off by using the spring force to simplify the engagement operation while the actuation system manages the disengagement force requirement.
Data Source
AI summary
A clutch assembly comprises an actuation assembly, an outer ring, and an inner ring disposed radially inward of the outer ring and rotatable about an axis in first and second rotational directions. A first and second strut are rotatably disposed within first and second pockets of the outer ring and configured to be rotated by the actuation assembly. A first pawl and a second pawl are rotatably disposed within a third pocket and a fourth pocket, respectively. For a transition mode, the actuation assembly is configured to rotate the first strut within the first pocket such that rotation of the first strut in the first rotational direction urges the first pawl radially inward into partial engagement with teeth disposed on an outer surface of the inner ring, the second pawl remains free of contact with the inner ring and the inner ring rotates in the first rotational direction.