Parking Interlock Coupling Device for Automatic Transmission
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Solution Overview
Problem
The existing parking interlock arrangements for automatic transmissions face limitations in functional reliability due to restricted actuating force and increased selecting torque, which compromises the ability to effectively lock the vehicle in the park position.
Innovation Solution
A parking interlock arrangement that utilizes a coupling device to independently set the actuating force of the connecting rod, allowing for increased actuating force on the locking pawl while reducing the selecting torque, and incorporates a connecting rod spring and compensating spring to enhance reliability and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the connecting rod is directly actuated by the notched disk or detent lever, then the structure is simple, but the actuating force is limited and selecting torque increases
Solution Approach 1:
A coupling device with rod elements and guide elements is introduced as an intermediary between the connecting rod and the notched disk. This mediator allows the actuating force to be amplified independently of the selecting force by decoupling the force transmission path from the rotation path, resolving the contradiction between high actuating force and low selecting torque
2Reliability
If the connecting rod is directly actuated by the notched disk, then the structure is simple, but the functional reliability is compromised
Solution Approach 1:
The coupling device segments the force transmission function from the rotation control function by using separate rod elements and guide elements. This segmentation allows each component to be optimized for its specific function, improving reliability while keeping individual components simple
Solution Approach 2:
The coupling device acts as a mediator that provides stable and reliable force transmission through guided rod elements, improving functional reliability without requiring complex redesign of the entire system
3Reliability
If higher actuating force is applied to the locking pawl, then the parking interlock reliability improves, but the selecting torque increases
Solution Approach 1:
The coupling device with guide elements acts as a mediator that allows high actuating force to be applied to the locking pawl through the rod elements without transmitting this force as torque to the selector shaft, thus improving parking interlock reliability while keeping selecting torque low
Solution Approach 2:
The force transmission path is segmented into independent rod elements that can provide high actuating force separately from the rotation path, allowing reliable parking interlock without increasing selecting torque
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 significantly improves the functional reliability and selecting comfort of the parking interlock arrangement by allowing higher actuating forces without increasing shifting or selecting forces, ensuring the vehicle remains securely locked in the park position.
Implementation Method 1
a connecting rod spring, by means of which axially movable locking rollers can be stressed in order to actuate the locking pawl
Implementation Method 2
at least one compensating spring can be used for the coupling device. The compensating spring is used to compensate for increased connecting rod forces or actuating forces during shifting
Data Source
AI summary
A parking interlock arrangement for an automatic transmission of a vehicle which comprises a parking interlock gear (1) operatively connected to an output shaft and which can be locked by way of a locking pawl (2) in a shift position (P) of a notched disk (4). The notched disk (4) is connected, in a rotationally fixed manner, to a selector shaft (5). The locking pawl (2) can be actuated by way of a connecting rod (3), and the connecting rod (3) is operatively connected to the notched disk (4) by way of a coupling device in order to limit the selecting torque to be applied to the selector shaft (5).