Electric Vehicle Transmission With Differentiated Electric Machines
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Solution Overview
Problem
Current electric vehicle transmissions with multiple gear ratios are costly and require variations in torque compensation, which existing technologies fail to address effectively.
Innovation Solution
A transmission device with at least two electric machines of different technical characteristics, where one machine handles primary propulsion and the other provides additional torque during acceleration or torque compensation, using a system of gears and coupling mechanisms to select transmission ratios and prevent torque transmission when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two identical electric machines are used to compensate for torque variations during gear changes, then torque continuity is improved, but cost increases
Solution Approach 1:
The patent applies local quality by assigning different roles and specifications to the two electric machines. The first electric machine is designed with high performance characteristics to provide continuous torque, while the second electric machine has reduced specifications and lower cost. This differentiated approach allows torque compensation during gear changes without requiring both machines to be identical, thereby reducing overall system cost while maintaining torque continuity.
2Ease of manufacture
If a second electric machine with degraded characteristics is used to reduce costs, then cost decreases, but torque delivery capability worsens
Solution Approach 1:
The patent applies preliminary action by having the second electric machine pre-loaded and ready to activate before gear changes occur. The control system detects upcoming gear changes and activates the second electric machine in advance to compensate for torque variations. This timing strategy ensures that even though the second machine has degraded characteristics, it can still effectively compensate for torque drops by being activated at the precise moment needed, maintaining overall torque delivery.
3Adaptability or versatility
If multiple gears with coupling means are added to select transmission ratios, then adaptability improves, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the transmission system into distinct gear modules (first gear, second gear, third gear), each with its own coupling means. This modular segmentation allows independent control and selection of different transmission ratios. Each gear module can be engaged or disengaged independently through its coupling means, providing adaptable transmission ratio selection while keeping the overall system manageable through modular architecture.
Data Source
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AI summary
The invention relates to a transmission device (T) with at least two transmission ratios, in particular for electric vehicle, the transmission device (T) comprising: - a first electric machine (M1) connected to a primary shaft (1), - a second electric machine (M2) connected to a secondary shaft (2), - a tertiary shaft (3) connected to the primary shaft (1) and to the secondary shaft (2) via gears (10, 20, 30) corresponding to said transmission ratios, characterized in that the first electric machine (M1) has different technical characteristics from the second electric machine (M2).