Electric Powertrain Gear Module for Multi-Speed EV Efficiency
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Solution Overview
Problem
Conventional electric powertrains face inefficiencies at high speeds and low torque, require multiple reduction stages for torque demand, leading to increased noise, vibrations, and high production costs due to the need for various powertrain configurations for different vehicle types.
Innovation Solution
A compact and robust electric powertrain design featuring a gear module architecture with countershafts and coupling members that allow for selective gear engagement, providing a higher number of speed ratios and improved efficiency, adaptable to a wide range of vehicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a fixed speed gearbox is used to achieve torque demand, then the reduction ratio is maintained, but the electric motor efficiency decreases at high speed and low torque conditions
Solution Approach 1:
The patent applies a variable ratio transmission system where the gear ratio can dynamically change based on operating conditions. The transmission includes a first gear ratio for high torque conditions and a second gear ratio for high speed conditions, allowing the system to adapt to different operational requirements and maintain optimal motor efficiency across various speed and torque ranges.
2Force
If a fixed speed gearbox with high reduction ratio is used to meet torque demand, then torque is sufficient, but the durability of transmission components decreases due to increased stresses
Solution Approach 1:
The variable ratio transmission allows the system to use a lower first gear ratio when high speed operation is required, reducing the stress on gears, bearings, and sealing rings. This dynamic adjustment prevents excessive stresses that would otherwise occur in fixed ratio transmissions operating at high speeds, thereby improving transmission durability.
3Power
If gears rotate at high speed to meet power demand, then power output is sufficient, but lubrication problems occur due to centrifugal force ejecting oil
Solution Approach 1:
The variable ratio transmission system enables the use of a lower first gear ratio during high-speed operation, which directly reduces the rotational speed of the gears. This speed reduction prevents the centrifugal force from ejecting lubricating oil, ensuring proper lubrication is maintained even during high-power output conditions.
4Power
If high rotation speed is used to meet power demand, then power output is sufficient, but noise and vibrations increase
Solution Approach 1:
The variable ratio transmission allows the system to select an appropriate gear ratio based on operating conditions. By using the first gear ratio for high-speed operations, the system reduces gear rotation speeds, thereby minimizing noise and vibrations generated during power delivery while maintaining sufficient power output.
5Adaptability or versatility
If multiple powertrain configurations are developed for different vehicle types, then vehicle-specific performance is optimized, but production costs significantly increase
Solution Approach 1:
The patent describes a variable ratio transmission system that can be adapted across different vehicle types and duty classes. The transmission includes a housing with a receiving space that can accommodate different electric motor configurations, allowing a single transmission design to serve multiple applications from low-duty to heavy-duty vehicles, thereby reducing development and production costs.
6Volume of moving object
If the powertrain is made compact to free space for batteries, then space for batteries is increased, but the number of reduction stages must be minimized
Solution Approach 1:
The variable ratio transmission achieves multiple effective gear ratios within a compact structure by using a single-stage design with variable ratio capability. This eliminates the need for multiple fixed reduction stages, maintaining compact powertrain volume while providing the necessary torque multiplication and speed variation through the variable ratio mechanism.
Data Source
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Figure 9~11
AI summary
The invention relates to an electric powertrain (1) for a vehicle, the electric powertrain (1) configured to provide electric propulsion to the vehicle characterized in that the electric powertrain (1) comprises: - a first electric motor (EM1) linked to a first gear module (G1) through a motor shaft (14), said first gear module (G1) including a primary shaft (34) on which are arranged a first primary gear (31) and a second primary gear (32), - a second gear module (G2) including a secondary shaft (44) on which are arranged a first secondary gear (42) that is meshing with the second primary gear (32), - at least one countershaft (60) on which are arranged a first quaternary gear (61) and a second quaternary gear (62), - a coupling member (19) arranged at the first extremity (E11) of the primary shaft (34).