Parking Lock Assembly with Releasable Coupling
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Solution Overview
Problem
Existing parking lock arrangements for motor vehicle transmissions face challenges in reliably setting and maintaining the parking lock position, particularly when the shift drum is faulty or cannot be rotated, leading to unintended release of the parking lock.
Innovation Solution
A parking lock arrangement featuring a roller actuator that can be rotated between basic and parked positions, coupled with a lever mechanism and a releasable coupling device, allowing actuation via either the shift drum or an electrical release signal to ensure the parking lock pawl is properly engaged, with mechanical preloading to maintain the lock position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shift drum is used to actuate the parking lock, then the parking lock can be engaged, but the system becomes vulnerable to faults or non-rotation of the shift drum
Solution Approach 1:
The patent changes the actuation parameter from solely mechanical (shift drum rotation) to include both mechanical and electrical actuation methods. The electrical actuator can independently actuate the parking lock pawl when the shift drum is faulty, providing an alternative actuation parameter that maintains reliability while adding versatility to the system.
2Reliability
If a single actuation mechanism is used, then the device complexity is reduced, but the safety redundancy is insufficient
Solution Approach 1:
The patent implements beforehand cushioning by providing an electrical actuator as a pre-prepared backup mechanism. This electrical actuator remains dormant during normal operation but is ready to activate immediately if the mechanical shift drum actuation fails, thus cushioning against potential parking lock engagement failures without adding significant complexity to the overall system.
3Stability of the object's composition
If the actuating lever is mechanically preloaded, then the parking lock position is maintained, but the coupling device must be releasable for fault conditions
Solution Approach 1:
The patent applies dynamics by making the coupling device between the actuating lever and cam lever releasable rather than permanently fixed. This allows the system to transition between coupled and uncoupled states: coupled during normal operation to maintain mechanical preload and position stability, and uncoupled when electrical actuation is needed, thus adapting the connection state to operational requirements.
Data Source
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AI summary
Parking lock assembly (30) for a motor vehicle transmission (16) comprising a housing (22), a parking lock wheel (32) which can be connected to a shaft (36) of the motor vehicle transmission (16), a parking lock pawl (38) which can be pivoted about a housing-fixed pawl axis (40) between a parking lock position and a release position, wherein the parking lock pawl (38) engages with the parking lock wheel (32) in the parking lock position and prevents its rotation, an actuating mechanism (50) for the parking lock pawl (38) and an actuator assembly (58) for the actuating mechanism (50), wherein the actuator assembly (58) has an actuating element which can be moved between a basic position (R) and a parking position (P) and is coupled to the actuating mechanism (50).In this arrangement, an actuating element such as an actuating lever (76) is coupled to the actuator and to the actuating mechanism (50) via a releasable coupling device (82), wherein the actuating element (76) is furthermore mechanically biased in one direction in order to push the parking lock pawl (38) into the parking lock position via the actuating mechanism (50), and wherein the coupling device (82) is designed such that it can be released by means of an electrical release signal (86).