Dog Clutch Phase Alignment for Low-Noise Drivetrain Shifting
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Solution Overview
Problem
Current vehicle drivetrain technologies face challenges in reducing mechanical noise and wear during gear engagement and dog clutch engagement, particularly due to the complexity and high cost of synchronizers and dog clutches.
Innovation Solution
A method and drivetrain system utilizing a dog clutch with two operating modes: an initial phase shift identifying mode and a normal operating mode, where the system controls a dog clutch with a first and second set of teeth, using an electrical propulsion motor and actuator to perform clutch engagement movements and identify the initial phase shift for interference-free engagement, allowing for cost-efficient and robust gear shifting without increased noise and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If synchronizers are used during gear shifting to reduce mechanical noise and wear, then noise and wear are reduced, but manufacturing cost and device complexity increase due to high manufacturing precision requirements
Solution Approach 1:
The patent extracts and removes the synchronizer component from the gear shifting system, replacing it with a dog clutch mechanism. This eliminates the need for complex friction surfaces and precision manufacturing while achieving the same noise and wear reduction goals through a simpler mechanical design.
Solution Approach 2:
Instead of using synchronizers to synchronize speeds before engagement, the patent inverts the approach by using a dog clutch with precisely controlled engagement timing and phase alignment. The control system calculates optimal engagement parameters to ensure smooth, low-noise engagement without requiring synchronizer friction surfaces.
2Reliability
If dog clutch teeth geometry is modified to improve gear engagement, then engagement performance improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the control parameters of the dog clutch engagement process rather than modifying the physical geometry of the teeth. By adjusting engagement timing, axial position, and rotational phase through the control system, optimal engagement performance is achieved while keeping the tooth geometry simple and easy to manufacture.
Solution Approach 2:
The patent replaces mechanical modifications to the dog clutch teeth with an electronic control system that calculates and controls engagement parameters. This substitution allows for precise engagement control through software algorithms rather than complex mechanical tooth designs, simplifying manufacturing.
3Object-affected harmful factors
If precise angular position control is implemented for interference-free dog clutch engagement, then noise and wear are reduced, but control system complexity increases
Solution Approach 1:
The patent implements a feedback control system that uses sensors to detect the actual angular positions of the clutch components and compares them with the calculated optimal positions. The control system continuously adjusts the engagement parameters based on this feedback to achieve precise, interference-free engagement while minimizing noise and wear.
Solution Approach 2:
The control system performs preliminary calculations of the optimal engagement parameters before the actual engagement occurs. By pre-calculating the required axial position, angular position, and timing based on the current state of the drivetrain, the system prepares the optimal engagement sequence in advance, reducing the complexity of real-time control during the actual engagement.
Data Source
AI summary
A method for operating a vehicle drivetrain having a dog clutch and an initial phase shift identifying mode and a normal operating mode. The method includes providing a dog clutch for selective torque transmission, wherein the dog clutch has a first clutch portion with a first set of teeth and a second clutch portion with a second set of teeth, and wherein the first clutch portion is axially moveable for enabling shifting of the dog clutch between an engaged state, in which the first and second clutch portions are operable to transmit torque between first and second clutch portion via the first and second set of teeth, and a disengaged state, in which the first and second clutch portions are rotatable with respect to each.