Transmission Parking Lock Using Pump-Driven Cam and Ratchet
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high cost and space requirements of electrically driven actuators in parking locks for automatic transmissions in electric or hybrid vehicles make them expensive and inefficient.
Innovation Solution
Designing a parking lock that uses the rotational movement of a media pump's drive shaft to actuate a ratchet wheel mechanism, allowing for alternating locking and unlocking with a conventional pawl, and incorporating a camshaft and preload unit to adjust the pawl between engagement and release positions, reducing the need for a dedicated electric actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrically driven actuator is used for the parking lock, then the parking lock can be actuated reliably, but the production costs and space requirements increase significantly
Solution Approach 1:
The media pump drive shaft is designed to perform dual functions: driving the media pump and actuating the parking lock through the cam mechanism. This eliminates the need for a separate electric actuator, reducing production costs while maintaining reliable parking lock functionality through the existing pump operation cycles.
Solution Approach 2:
The parking lock actuation mechanism is merged with the media pump drive system. The camshaft, driven by the media pump motor, integrates the locking and unlocking functions into the existing pump operation, eliminating redundant components and reducing overall system cost.
2Reliability
If an electrically driven actuator is used for the parking lock, then the parking lock can be actuated reliably, but the structural space required increases
Solution Approach 1:
The media pump drive shaft serves dual purposes: driving the media pump and actuating the parking lock. This eliminates the need for a separate electric actuator and its associated mounting space, reducing the overall structural space required in the transmission housing.
Solution Approach 2:
The parking lock mechanism is nested within the existing media pump drive structure. The camshaft and pawl mechanism are integrated into the pump housing, utilizing existing structural spaces rather than requiring additional dedicated space for actuator mounting.
3Ease of manufacture
If a camshaft mechanism is used to convert rotational movement to alternating locking/unlocking, then a dedicated electric actuator is eliminated, but the mechanism complexity increases
Solution Approach 1:
The camshaft acts as an intermediary mechanism that converts the continuous rotational movement of the media pump drive shaft into the alternating linear motion required for pawl engagement and disengagement. This simple mechanical intermediary eliminates the need for complex electric actuator control systems while maintaining manageable mechanism complexity.
4Ease of operation
If the pawl is preloaded in the release position, then the transmission is not blocked when the actuator is inactive, but an additional preload unit is required
Solution Approach 1:
The preload unit pre-positions the pawl in the release position before actuation is required. This preliminary action ensures that the transmission remains operable during normal operation and only blocks when the parking lock is intentionally engaged, eliminating the need for complex control logic while adding only a simple spring mechanism.
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 solution reduces production costs and space requirements while maintaining effective locking functionality, allowing for seamless transitions between brake and accelerator pedals without vehicle roll-away, particularly on inclines.
Implementation Method 1
The parking lock furthermore comprises a camshaft which is rotatable about an axis of rotation and on which there is arranged a cam which is connected in terms of drive to the lock device. The cam and the lock device are designed and coordinated with one another such that, when the camshaft rotates, the actuating element is actuated by the cam.
Implementation Method 2
The parking lock comprises a ratchet wheel, which is rotatable about a wheel axis, and a pawl, which interacts with the ratchet wheel. Said pawl is adjustable between an engagement position, in which it blocks a rotation of the ratchet wheel, and a release position, in which the blocking of the ratchet wheel is eliminated.
Implementation Method 3
In one advantageous refinement, the lock device comprises a preload unit which preloads the pawl in the direction of the release position.
Data Source
AI summary
A parking lock for a transmission of an electric or hybrid vehicle is disclosed. The parking lock includes a lock device including an actuatable actuating element and a setting element adjustable between a deployed position and a retracted position. The locking device is configured such that, in response to repeated actuation of the actuating element, the setting element is, via a coupling mechanism, adjusted alternately between the retracted position and the deployed position. A camshaft is provided with a cam arranged on the camshaft that is connected in terms of drive to the lock device. A ratchet wheel is provided with a pawl that is adjustable between an engagement position, where the pawl blocks a rotation of the ratchet wheel, and a release position, where the blocking of the ratchet wheel is released. The setting element adjusts the pawl between the engagement position and the release position.