Parking Lock Actuating Contour for Lower Release Force
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Solution Overview
Problem
Existing parking lock arrangements in automatic transmissions face issues with high dynamic and high-frequency loads causing micro-movements, leading to a loss of self-locking due to clearance fits and low geometric overlap, which results in increased actuation forces and mass, negatively affecting installation space and housing loads.
Innovation Solution
The actuating contour of the actuating element is designed as a rotationally symmetrical circular arc along its longitudinal axis, reducing mass and actuation forces while maintaining robust self-locking behavior, with a constant or variable interlocking angle to minimize release forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actuating element uses a conventional linear taper angle design, then the self-locking function is maintained, but the actuation forces increase and the mass increases
Solution Approach 1:
The actuating element uses a circular arc contact surface instead of a linear taper, creating a curved geometry that maintains self-locking through variable interlocking angle while reducing the required actuation force. The circular arc profile allows the contact point to move along a curved path, providing mechanical advantage throughout the actuation stroke.
Solution Approach 2:
The invention changes the geometric parameter from a constant linear taper angle to a variable interlocking angle along the circular arc. This parameter variation allows optimization of the force distribution, maintaining high self-locking reliability at the engaged position while reducing the peak actuation force required during engagement.
2Reliability
If the actuating element uses a conventional linear taper angle design, then the self-locking function is maintained, but the installation space increases
Solution Approach 1:
The circular arc geometry of the actuating element allows for a more compact design compared to the linear taper. The curved profile enables the force application point to follow an optimized path, reducing the axial and radial dimensions required for the same self-locking performance, thereby decreasing the overall installation space.
3Device complexity
If the actuating element uses a conventional linear taper angle design, then the structural simplicity is maintained, but the mass increases
Solution Approach 1:
The circular arc profile allows the actuating element to be designed with optimized material distribution. The curved geometry provides structural efficiency, allowing reduction of material cross-section in non-critical areas while maintaining strength and self-locking function, thereby reducing mass without significantly increasing manufacturing complexity.
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 design reduces the necessary installation space and mass of the actuating element, enhances robustness against self-locking loss, and simplifies production and installation, while minimizing actuation forces and housing loads.
Implementation Method 1
self-locking always takes place at the actuating element for the case in which the sum of the existing friction forces is greater than the sum of the forces that result in the axial displacement of the actuating element
Implementation Method 2
The actuating element is axially displaceably mounted on the actuating rod and, during the engagement and disengagement of the parking lock, is in contact with an actuating zone of the parking pawl as well as with a support contour of a housing-affixed guide element
Data Source
AI summary
A parking lock arrangement with an actuating device for engaging and disengaging a parking pawl (10) for interlocking and releasing a parking interlock gear (20) includes an axially movable actuating rod (30) with an axially displaceable actuating element (40) on an end facing the parking pawl (10). During the engagement and disengagement of the parking lock, an actuating contour (41) of the actuating element (40) is in contact with an actuating zone (13) of the parking pawl (10) and with a support contour (51) of a housing-affixed guide element (50). The actuating contour (41) is designed to be rotationally symmetrical with respect to a longitudinal axis (42) of the actuating element (40) and extends along this longitudinal axis (42). The actuating contour (41) is a circular arc as viewed in the direction of the longitudinal axis (42) of the actuating element (40).