Two-Ratio Torque Transmission with Clutch Drag Torque Isolation
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Solution Overview
Problem
Existing torque transmission devices in hybrid and electric vehicles face inefficiencies due to drag torque in clutches, significant dimensioning and mass requirements, and mechanical strength issues caused by high rotational speeds, particularly when using wet clutches and high-speed electric motors.
Innovation Solution
A torque transmission device with two speed ratios, utilizing a connection element that interrupts the drive between the first clutch's output and the transmission mechanism when the second clutch is closed, reducing drag torque and avoiding excessive centrifugation, and employing progressive multi-disc clutches for smooth gear changes and improved energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If clutches are used to select reduction ratios in a transmission device, then speed and torque adaptation is achieved, but drag torque occurs on open clutches which reduces efficiency
Solution Approach 1:
The patent extracts the harmful drag torque effect by introducing a connecting element that selectively interrupts the drive path. When the second clutch is closed, the connecting element disconnects the first clutch's output from the transmission member, removing the source of drag torque while preserving the clutch's ability to engage when needed for speed/torque adaptation.
Solution Approach 2:
The connecting element acts as an intermediary between the first clutch and the transmission member. It mediates the power flow by being able to connect or disconnect the drive path, allowing the system to maintain adaptability while eliminating the harmful drag torque effect on open clutches.
2Force
If clutches transmit large torque, then the transmission device can handle high torque requirements, but the clutches become large in size and mass
Solution Approach 1:
The patent segments the torque transmission path into two separate clutches (first and second clutches) with different functions. The first clutch handles starting torque with a smaller size, while the second clutch handles high-speed torque. This segmentation allows each clutch to be optimized for its specific torque requirement, reducing overall mass compared to a single large clutch handling all torque.
3Speed
If the first transmission mechanism acts as a speed multiplier with high-speed electric motor, then the output element rotates at very high speed, but mechanical strength problems occur
Solution Approach 1:
The patent applies preliminary anti-action by using the connecting element to preemptively disconnect the first clutch's output from the transmission member when the second clutch is closed. This prevents the harmful high-speed rotation from occurring in the first transmission mechanism, countering the mechanical strength problem before it can manifest.
Solution Approach 2:
The patent converts the potentially harmful high-speed rotation into a beneficial configuration by using the connecting element to selectively engage or disengage the first transmission path. When disconnected, the first transmission mechanism is protected from excessive speeds; when engaged, it provides useful speed multiplication at appropriate operating conditions.
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
This solution enhances the safety and efficiency of torque transmission by minimizing drag torque, reducing clutch size and mass, and preventing mechanical strength issues, while maintaining user comfort through smooth acceleration and reduced energy losses.
Implementation Method 1
the opening of the connection element makes it possible to avoid excessive centrifugation of the first output element of the first clutch which could rotate at a speed higher than that of the engine
Implementation Method 2
The use of clutches, particularly progressive multi-disc clutches, also helps ensure user comfort by avoiding sudden gear changes and perceptible variations in acceleration
Data Source
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AI summary
The invention relates to a torque transmission device (10) for a vehicle comprising at least one electric motor (4), the torque transmission device comprising: - a first clutch (1) - a second clutch (2) - a transmission member (5), - a first transmission mechanism (11), between the first clutch and the transmission member, - a second transmission mechanism (12), between the second clutch and the transmission member, - a connection element (6) designed to allow or interrupt the mutual driven rotation between a first output element (33) of the first clutch (1) and the transmission member (5), by means of the first transmission mechanism (11).