Dual-Motor Transmission Powershifting Without Output Torque Drop
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Solution Overview
Problem
Existing dual-motor electrical transmissions for vehicles face inefficiencies and safety concerns in power shifting, particularly in high-performance applications, where maintaining output torque during gear shifts is crucial for optimal performance and safety.
Innovation Solution
A dual-motor electrical transmission system with two electric motors, multiple gear arrangements, and a summation box, utilizing clutch elements that can be selectively engaged and disengaged to maintain constant output torque during gear shifts, and a control method that synchronizes motor torques to prevent torque dips during shifting, incorporating spring-loaded or automatic disengagement mechanisms for safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single motor with multiple gear ratios is used, then the transmission structure is simpler, but the efficiency during gear shifts deteriorates due to torque drops
Solution Approach 1:
The transmission system is segmented into two independent electric motors (first and second motors) each with their own gear arrangements, allowing independent operation during gear shifts. This segmentation enables one motor to maintain torque output while the other motor's gear ratio is changed, eliminating the torque drops that occur in single-motor systems during gear shifts.
2Device complexity
If traditional gear shifting is used in single-motor transmissions, then the structure is simpler, but powershifting capability deteriorates causing torque drops during shifts
Solution Approach 1:
The patent merges two motor-gear systems into a single transmission unit with a common output shaft. This combination allows the first and second motors to work cooperatively, where one motor can compensate for the other during gear ratio changes, maintaining stable output torque and achieving powershifting capability that would be difficult to obtain with a single motor system.
3Ease of operation
If clutch elements are used for gear engagement, then gear shifting is enabled, but functional safety deteriorates without automatic disengagement mechanisms
Solution Approach 1:
The patent incorporates spring-loaded disengagement mechanisms that automatically and preliminarily disengage the clutch elements from the gear arrangements under certain conditions (such as loss of actuation pressure or electrical failure). This preliminary safety action ensures that the clutch elements cannot remain engaged when they should be disengaged, preventing unsafe operation while still allowing normal engaged/disengaged operation during regular gear shifts.
Data Source
AI summary
A dual-motor transmission therefor, comprising a first and a second electric traction motor, a first gear arrangement, a second gear arrangement, and a summation box. The first gear arrangement includes a shaft and at least a first gear and a second gear, wherein each of the first and the second gears can be selectively engaged and disengaged with the shaft via a clutch, and the first gear arrangement supplies a first torque from the first motor to the summation box. The second gear arrangement includes a shaft and at least a first gear, wherein the first gear can be engaged and disengaged with the shaft via a clutch, and the second gear arrangement supplies a second torque from the second motor to the summation box, and the summation box is configured to combine the first and second torques and to output a combined output torque.