Transmission Shift Fork Actuation With Cam-Driven Lever Arm
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing driveline shifting systems in commercial vehicle transmissions face issues with small rotational actuation accuracy and increased wear due to the use of parallel axle gear trains, which result in potential backlash and reduced accuracy.
Innovation Solution
A low rotation angle actuation system is implemented, comprising a motor coupled to a lever arm via a parallel axis gear train and a shaft connected to a driveline shifting member, with a rolling element housed within a slot in the lever arm and an eccentric pin on the final gear to create a cam effect, allowing for precise and efficient gear engagement with increased torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If parallel axis gear trains are used to actuate the shift fork, then gear engagement can be achieved, but backlash and reduced accuracy occur due to small number of teeth working in final stages
Solution Approach 1:
The patent replaces the traditional parallel axis gear train with a cam-based mechanical system. The cam profile is specifically designed to convert rotational motion into precise linear displacement of the shift fork, eliminating the backlash and tooth engagement issues inherent in gear trains. The cam mechanism provides direct, backlash-free actuation while maintaining the desired small rotational output.
2Speed
If parallel axis gear trains are used with small rotational output, then high speed actuation is achieved, but wear increases due to changes in gear clearance
Solution Approach 1:
The cam-based system replaces the gear train to eliminate wear-related issues. The cam profile is designed to provide the necessary motion profile without the clearance changes that occur in gear meshes, thereby extending component life while maintaining high actuation speed.
Solution Approach 2:
The cam mechanism allows for optimized dynamic performance by designing the cam profile to provide smooth acceleration and deceleration of the shift fork, reducing impact loads and wear while maintaining high actuation speeds.
3Measurement precision
If small rotational movement is required for shift fork actuation, then precision is improved, but torque requirement increases
Solution Approach 1:
The cam profile utilizes curved geometry to provide mechanical advantage. The cam shape is specifically designed to convert small rotational movements into the required linear displacement while optimizing the force distribution, thereby reducing the peak torque requirements compared to a direct rotational-to-linear conversion 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 enables accurate and efficient small rotational movements of the shift fork, reducing wear and improving gear engagement speed, while maintaining a simplified and cost-effective component arrangement for multiple driveline members.
Implementation Method 1
A cam is established by using an eccentric pin on a final gear of the gear train in which the rolling element is mounted
Implementation Method 2
the lever arm driven via a rolling element housed within a slot in the lever arm
Data Source
AI summary
Methods and systems are provided for an actuation system for a driveline shifting member in a transmission system of a vehicle. In one example, a system may include an actuator coupled to a lever arm via one or more parallel axis gears, and a shaft connecting the lever arm to a driveline shifting member, the lever arm driven via a rolling element housed within a slot in the lever arm aligned with a center of a parallel axis gear of the one or more parallel axis gears.