Driveline Shift Drum Parking Lock Mechanism
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Solution Overview
Problem
Existing vehicle drivelines require additional actuators to prevent rolling off when parked, which increases complexity and cost.
Innovation Solution
Incorporating a further cam profile and cam follower on the shift drum, connected via a gear set mechanism to a locking element, which locks a drive shaft connected to the differential, eliminating the need for a separate actuator by utilizing the existing shift drum for locking the output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate additional actuator is used to lock the driveline output when parked, then the vehicle can be secured against rolling off, but the device complexity and cost increase
Solution Approach 1:
The shift drum is designed to perform dual functions: its original function of actuating shift forks for gear changes, and a new function of actuating the parking lock through an additional cam profile. This multi-functionality eliminates the need for a separate actuator, reducing device complexity while maintaining the security function against rolling off
Solution Approach 2:
The parking lock actuation mechanism is merged with the existing shift drum mechanism. The additional cam profile on the shift drum combines the gear shifting and parking lock functions into a single integrated system, controlled by the same actuator, thereby reducing overall system complexity
2Reliability
If a separate additional actuator is used to lock the driveline output when parked, then the vehicle can be secured against rolling off, but the cost increases
Solution Approach 1:
The shift drum serves multiple purposes including gear shifting and parking lock actuation, eliminating the need to manufacture and install a separate actuator. This reduces manufacturing costs by utilizing existing components for multiple functions
Solution Approach 2:
The existing shift drum system serves itself by taking on the additional responsibility of actuating the parking lock. This self-service approach eliminates the need for separate components and reduces overall system cost
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 provides a simple and cost-effective method to prevent vehicle rolling off during parking without additional actuators, reducing complexity and enhancing reliability.
Implementation Method 1
The further cam follower is kept in contact with the side wall of the recess preferably by means of a spring
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A driveline 1 comprises a transmission 7 having an input shaft 9 and an output shaft 13 as well as an end drive 19 connected to the output shaft of the transmission, which end drive includes a differential 21. The transmission comprises a plurality of switchable gear trains as well as a shift drum 23 which has three cam profiles 25, 27, 29 and three shift forks SOI, S23, S4X provided with cam followers for moving a clutch element for coupling a gear to a shaft present in the transmission. The shift drum 23 further includes a further cam profile 31 and the transmission comprises a further cam follower F4 as well as a locking element which is connected via a gear unit 35 to the further cam follower and locks a driving element 37 in the driveline so that drive shafts connected to the differential are locked against rotation.