Wire Parking Actuator Assembly for Automatic Transmission
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Solution Overview
Problem
Conventional electronically actuated park engagement systems for automatic transmissions are complex, bulky, and expensive due to the need for external parking brake mechanisms with redundant electromechanical components to ensure safety and functionality during power loss situations.
Innovation Solution
Integration of a parking actuator assembly within the transmission system, including a park actuator motor, latching solenoids, and position sensors, which features a robust rolling actuator assembly with continuous contact points and redundant latching mechanisms to ensure reliable park engagement and disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external parking brake system with redundant electromechanical actuators is used, then safety and reliability during power loss are improved, but device complexity and system size increase
Solution Approach 1:
The patent combines the parking brake actuator directly with the transmission assembly, integrating the motor, gear train, and parking pawl into a single unified system. This eliminates the need for separate external electromechanical actuators and redundant components, reducing overall system complexity while maintaining reliability through the inherent mechanical advantage of the integrated design
Solution Approach 2:
The patent extracts and eliminates unnecessary redundant electromechanical components from the traditional external parking brake system. By using a simple motor-driven gear train directly integrated into the transmission, the design removes excess actuators, sensors, and control mechanisms while preserving the essential parking function and safety requirements
2Reliability
If an external parking brake system with redundant components is used, then safety during power loss is improved, but manufacturing cost increases
Solution Approach 1:
The integration of the parking brake actuator with the transmission assembly reduces the total number of parts that need to be manufactured, assembled, and quality-tested. The unified design allows for more efficient production processes and reduces inventory requirements for multiple redundant components, thereby lowering manufacturing costs
3Reliability
If a robust rolling actuator assembly with continuous contact points is used, then reliability of park engagement is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex multi-point contact mechanisms with a simpler motor-driven gear train that provides reliable mechanical advantage. The continuous engagement is achieved through the inherent mechanical coupling of the gear train and parking pawl, eliminating the need for multiple sensors and actuators while maintaining reliable park engagement
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 solution provides a compact, reliable, and cost-effective park engagement system that defaults to park in power loss situations and maintains out-of-park configuration integrity, reducing the need for external components and enhancing safety and control.
Implementation Method 1
A solenoid having a solenoid plunger, the solenoid being configured to actuate the solenoid plunger to latch the park lever to hold the actuator assembly in the park-disengaged position
Data Source
AI summary
A parking actuator assembly for an automatic transmission includes a park pawl that is rotatable between an in-park position and an out-of-park position. An actuator assembly is configured to be moved between a park-actuated position and a park-disengaged position, the actuator assembly being configured to rotate the park pawl into the in-park position when the actuator is moved into the park-actuated position. An actuator rod is slidably coupled to the actuator assembly. In some forms, the actuator assembly remains in contact with the park pawl from the park-actuated position to the park-disengaged position. In some forms, at least one latching solenoid is included, and the latching solenoid(s) as well as a park actuator motor may be disposed within a main transmission system. A verification sensor may be included to determine the position.