EV Drive Dog Coupling with Electric Motor Speed Synchronization
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Solution Overview
Problem
Existing drives with electric motors and transmissions for electric vehicles are complex, costly, and inefficient due to mechanical synchronization methods that result in poor shifting performance and traction disruptions during gear changes.
Innovation Solution
The drive system employs an electric synchronizing device to adjust the motor's rotational speed, eliminating the need for mechanical synchronization, allowing for a simple, cost-effective, and low-wear transmission design with positive engagement between the drive shaft and output shaft via a dog and window mechanism, enabling rapid and smooth gear changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical synchronization methods are used for gear shifting, then the transmission can achieve rotational speed matching, but the device complexity increases and manufacturing cost rises
Solution Approach 1:
The patent replaces the mechanical synchronization device with an electrical synchronization system that uses the electric motor's control capabilities to adjust rotational speed during shifting. The motor controller electronically adjusts the motor speed to match the required synchronization speed, eliminating the need for mechanical friction-based synchronizers and their associated complex mechanisms.
Solution Approach 2:
The patent changes the synchronization approach from mechanical parameter adjustment (friction-based speed matching) to electrical parameter control (motor speed adjustment via control signals). The motor's rotational speed parameter is dynamically adjusted during the shifting process to achieve synchronization without mechanical contact.
2Reliability
If mechanical synchronization devices are employed, then rotational speed matching is achieved, but friction and wear increase
Solution Approach 1:
The patent eliminates mechanical friction-based synchronization by using electrical control of the motor speed. The synchronization is achieved through electromagnetic control rather than mechanical friction, completely avoiding the friction losses and wear associated with traditional synchronizing devices.
3Device complexity
If traditional gear shifting is performed without electric synchronization, then the transmission structure is simpler, but shifting time increases and productivity decreases
Solution Approach 1:
The patent uses electrical synchronization control to rapidly adjust motor speed during shifting, enabling fast gear changes without complex mechanical synchronization devices. The electronic control system can quickly calculate and implement the required speed adjustments, achieving high shifting speeds with minimal structural complexity.
4Reliability
If mechanical synchronization is used, then gear engagement is reliable, but the manufacturing cost increases
Solution Approach 1:
The patent replaces expensive mechanical synchronization devices with a software-based electrical control system. The motor controller uses algorithms to calculate and implement speed adjustments, eliminating the need for precision-machined synchronizing rings, friction surfaces, and associated mechanical components, thereby reducing manufacturing costs while maintaining engagement reliability.
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 approach results in a more efficient, comfortable, and reliable gear shifting process with reduced friction and wear, allowing for quick transmission ratio changes without kinetic energy conversion to heat, enhancing the driving experience in electric vehicles.
Implementation Method 1
an electric synchronizing device is provided with which a rotational speed of the electric motor can be changed to a second rotational speed for a duration of the shifting process
Data Source
AI summary
A drive with an electric motor and transmission connected to the electric motor at a drive shaft. Transmission has gears with different transmission ratios. The transmission performs a shifting process in which a coupling of the drive shaft, driven by the electric motor rotating at a first rotational speed, to the output shaft via a first gear with a first transmission ratio is first released, whereby the drive shaft is no longer rotationally coupled to the output shaft, after which the drive shaft is rotationally coupled to the output shaft via a second gear with a second transmission ratio. An electric synchronizing device is provided to change a rotational speed of the electric motor to a second rotational speed for a duration of the shifting process. The second rotational speed corresponds to the first rotational speed multiplied by a quotient of the second transmission ratio and first transmission ratio, and the drive is designed to produce a releasable rotational coupling between the drive shaft and the output shaft via the second gear by positive engagement. The drive shaft is releasably coupled to the output shaft via a gear by at least one dog engaging a depression in a window extending along a direction of an element coupled to the drive shaft movable relative to an element coupled to the output shaft when not coupled to the drive shaft during a shifting process, so that the dog is movable into the depression through the window.