Motor Vehicle Transmission Torque Path Synchronization
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Solution Overview
Problem
Existing motor vehicle transmission systems with central synchronization devices increase construction and control complexity, and require significant actuation force to engage and disengage clutches due to drag torque and friction, leading to inefficient gear shifting.
Innovation Solution
A transmission design with two switchable torque transmission paths, each including a friction clutch, allows for reduced actuation force by compensating drag torque and adjusting torque transmission ratios to minimize the force required for clutch operation, independent of input shaft synchronization, and includes a method for controlling these clutches to support clutch opening and closing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If central synchronization devices are used for gear shifting, then synchronization between input shafts is improved, but device complexity and control complexity increase
Solution Approach 1:
The patent extracts the synchronization function from a dedicated central synchronization device and integrates it into the existing torque transmission paths. The torque transmission paths are repurposed to serve dual functions: transmitting torque during power delivery and synchronizing input shafts during gear shifts. This eliminates the need for separate synchronization mechanisms while maintaining reliable synchronization between input shafts.
Solution Approach 2:
The torque transmission paths are designed to perform multiple functions: they transmit torque during normal power delivery and simultaneously serve as synchronization paths during gear shifting operations. By making these paths universal, the patent eliminates the need for dedicated synchronization devices, reducing construction complexity while maintaining synchronization reliability.
2Ease of operation
If conventional clutch designs are used for gear changing, then clutch engagement is achieved, but actuation force required increases due to drag torque and friction
Solution Approach 1:
The patent applies a counter-torque through the torque transmission paths that opposes the drag torque and friction forces acting on the clutch during engagement. By transmitting torque through the alternative path, a balancing moment is created that reduces the net force required to actuate the clutch, making the engagement process easier and reducing actuator size requirements.
Solution Approach 2:
Before the clutch engagement is completed, the torque transmission paths are activated to pre-load and balance the torque distribution. This preliminary action reduces the peak forces that would otherwise be required during the engagement process, making the operation smoother and reducing actuator demands.
3Force
If torque transmission paths with high transmission ratios are used, then actuation force is reduced, but synchronization capability may be affected
Solution Approach 1:
The patent employs dynamic control of the torque transmission paths, adjusting the torque distribution in real-time based on the synchronization requirements and gear shifting phase. The system dynamically balances the torque to achieve both force reduction and synchronization, adapting the torque split between paths as the shifting progresses to maintain optimal performance throughout the transition.
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
The design reduces the maximum actuation force needed for clutch operation, enabling a smaller and lighter actuator system, and allows for efficient synchronization during gear changes without interrupting power flow, particularly suitable for use with electric machines in motor vehicle drive trains.
Implementation Method 1
the torque transmission path includes a friction clutch
Data Source
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AI summary
Transmission (G) for a motor vehicle, wherein the transmission (G) comprises a drive shaft (GW1), two input shafts (W1, W2) each connectable to the drive shaft (GW1) via an input clutch (K1, K2) and each assigned to a sub-transmission (TG1, TG2), several shift clutches (S1a; S2a, S3a, S4a, S5a; S2, S3, S4, S5, S6, SR, K) and an output shaft (GW2) connected to both sub-transmissions (TG1, TG2) on the output side, wherein various gears (1 to 7, R1, R2) are selected between the drive shaft (GW1) and the output shaft (GW2) by selective actuation of the shift clutches (S1a; S2a, S3a, S4a, S5a; S2, S3, S4, S5, S6, SR, K) and the input clutches (K1, K2). can be represented, where a transmission ratio (iZ1) of a switchable torque transmission path (L1) between the input shafts (W1, W2) is greater than the largest step change between two adjacent gears (1 to 7);and a method for operating such a transmission (G) to relieve stress when opening one of the shift clutches (S1a; S2a, S3a, S4a, S5a; S2, S3, S4, S5, S6, SR, K) during its actuation.;