Park Actuator Assembly With Integral Collar for Transmission Reliability
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Solution Overview
Problem
Existing park actuator assemblies in automatic transmissions face issues with disengagement under extreme forces due to small contacting surfaces, leading to potential failure in maintaining the actuator on the actuator rod and unintended engagement with the park gear.
Innovation Solution
The park actuator assembly features an actuator rod with an integral collar and a spring enclosed within the actuator, along with tabs and a cam surface, allowing for improved engagement and disengagement mechanisms that reduce the risk of disengagement and enhance reliability, incorporating a solenoid assembly for ETRS systems that can accommodate both push and pull actuation modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the actuator uses a small contacting surface design, then the packaging space is reduced, but the reliability deteriorates due to disengagement under extreme forces
Solution Approach 1:
The actuator rod is segmented into multiple functional sections: a collar section with increased surface area for reliable engagement, a spring section for force application, and a rod section for actuation. This segmentation allows the collar to provide large contacting surface area for reliability while the overall actuator maintains compact dimensions for space efficiency.
Solution Approach 2:
The collar is designed with a larger diameter than the rod, creating a dimensional transition that increases the contacting surface area in the radial dimension. This dimensional change allows the actuator to engage reliably with the park pawl while maintaining a compact axial length for packaging constraints.
2Reliability
If the actuator assembly includes enclosed spring and collar components, then the operational reliability is improved, but the device complexity increases
Solution Approach 1:
The collar and spring are integrated into a single actuator rod assembly, where the collar is formed as an integral part of the rod and the spring is positioned within the actuator housing. This merging reduces the number of separate components and simplifies assembly while maintaining the reliability benefits of the collar and spring mechanism.
Solution Approach 2:
The spring is nested within the actuator housing, and the collar is integrated into the rod structure. This nested arrangement allows multiple functional components to be contained within a compact assembly, reducing overall complexity while maintaining reliable operation.
3Ease of operation
If the actuator rod extends beyond the actuator, then the engagement mechanism is simplified, but the risk of disengagement under extreme forces increases
Solution Approach 1:
The collar acts as a cushioning element that absorbs and distributes extreme forces before they can cause disengagement. By providing a large surface area contact point, the collar prevents the actuator rod from being pulled out under extreme loading conditions, thereby maintaining reliability while keeping the engagement mechanism simple.
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 configuration provides a more reliable and efficient park actuator system with reduced packaging size, fewer manufacturing steps, and improved operational reliability, minimizing the risk of the transmission being stuck in park mode.
Implementation Method 1
a spring enclosed within the actuator on the actuator rod
Data Source
AI summary
A parking actuator assembly for an automatic transmission includes an actuator rod, an actuator axially slidable on the actuator rod, and a spring enclosed within the actuator on the actuator rod.