Transmission Parking Pawl Actuation Assembly Design
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Solution Overview
Problem
Existing parking pawl actuation assemblies in transmissions are complex, heavy, costly, and occupy significant space without enhancing transmission performance, necessitating a more efficient and compact solution.
Innovation Solution
A parking pawl actuation assembly comprising a shaft, hub, cam plate, lever plate, resilient members, and an actuator that selectively positions the parking pawl to engage or disengage the parking gear, reducing complexity and weight while maintaining functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct acting actuators or mechanical linkages are used to engage a parking lock, then the parking function is achieved, but the complexity, weight, cost and package size increase
Solution Approach 1:
The patent combines multiple parking pawl actuation mechanisms into a single integrated assembly where the hub member integrates the cam plate, lever plate, and resilient members. This merging reduces the number of separate components and simplifies the overall structure while maintaining the parking lock function.
Solution Approach 2:
The hub member serves multiple functions: it supports the cam plate and lever plate rotation, provides mounting for resilient members, and transmits actuation forces. This multi-functionality reduces the need for separate dedicated components for each function, thereby reducing complexity.
2Reliability
If direct acting actuators or mechanical linkages are used to engage a parking lock, then the parking function is achieved, but the weight increases
Solution Approach 1:
The patent employs resilient members including a spring plate and compression spring that provide flexible, lightweight actuation forces compared to rigid mechanical linkages. These flexible elements reduce weight while maintaining the necessary force transmission for parking pawl engagement.
3Reliability
If direct acting actuators or mechanical linkages are used to engage a parking lock, then the parking function is achieved, but the package size increases
Solution Approach 1:
The patent nests the cam plate and lever plate within the hub member structure, with the cam plate positioned inside the hub's radial bore and the lever plate arranged adjacent to it. This nested arrangement compactly packs multiple moving components into a small volume, reducing the overall package size of the actuation assembly.
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
The assembly reduces complexity, weight, and package size while maintaining effective engagement and disengagement of the parking gear, thereby improving transmission efficiency and cost-effectiveness.
Implementation Method 1
The first resilient member is disposed between the cam plate and the lever plate. The resilient member applies a rotational force on the cam plate in a first rotational direction when the lever plate is rotated in the first rotational direction.
Implementation Method 2
The second resilient member disposed between the transmission housing and the spring plate. The second resilient member has a first and a second end, the first end configured to engage the spring plate and the second end configured to engage the housing of the transmission, and wherein the second resilient member applies a detent force to the spring plate when the spring plate is rotated.
Data Source
AI summary
A parking pawl actuation assembly for a transmission includes a shaft, a hub member rotatably supported by the shaft, a cam plate and lever plate rotatably supported by the hub member, a first resilient member disposed between the cam plate and the lever plate, and wherein the resilient member applies a rotational force on the cam plate in a first rotational direction when the lever plate is rotated in the first rotational direction, an actuator configured to selectively rotate the lever plate to one of a plurality of positions, and a parking pawl member configured to engage the cam plate and the parking gear of the transmission.