2-speed transmission

With automated gear changes for modern hybrid or electric trucks and buses.

Effective solution for expanding the possibilities of using the electric drive in the transmissions of modern vehicles

Effective solution for expanding the possibilities of using the electric drive in the transmissions of modern vehicles

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About the project

KATE's 2-speed transmission is designed to work in pairs with an electric motor in modern hybrid or electric trucks and buses. Two forward gears and one rear gear, maximum torque up to 800 Nm, maximum input shaft speed up to 4500 rpm.

The torque transmission is possible in both directions of rotation, and a flexible structural design provides the possibility to create a wide range of products.

The vehicles of the future are already being developed, which do not have the usual power plants and mechanical transmissions. They are replaced by new hybrid and electric circuits, in which the main element is the traction motor, gearing the driving axle. Nevertheless, even designing an electric motor specifically for a certain vehicle, it is difficult to ensure its maximum efficiency over the entire range of torque and speed. In this regard, electric transmission designs with two-speed transmissions for advanced vehicles often began to appear.

KATE LLC develops the most advanced solutions for vehicles and is pleased to take up the task in 2013. So, two-speed transmissions were developed in full accordance with the customer's technical requirements. They work as part of a set of traction electrical equipment in the electromechanical transmission of modern heavy-duty trucks or buses. Installation of two-speed transmissions implies their placement on the driving axle between the traction motor and the main transmission. The transmission has two forward gears and one reverse gear, a neutral position, and the possibility of semi-automatic gear shifting.

The neutral allows to safely tow the vehicle in the event of an electric motor failure, which was a specific requirement of the customer. The product is equipped with sensors for the engaged gear, which is indicated on the driver's display. Gear shifting occurs automatically after the corresponding request from the driver (by pressing a button), and it is also possible to implement an algorithm for fully automatic shifting.
Due to the possibility of torque transfer in both rotation directions, the electric motor is also used in the braking and recovery modes. The use of the gearbox is possible in different climatic zones in Russia at ambient temperatures from -50 to +50 degrees Celsius, and the product itself is equipped with an oil temperature sensor.

The serial detailed design documentation is developed and the production of the transmission is being prepared

The first prototypes were manufactured and tested as early as 2014. Based on the results of functional and durability tests, changes were made and a repeated cycle of production and testing of prototypes was carried out. Now, serial detailed design documentation has already been developed for the 2-speed transmissions and their production is being prepared. Prospects for the development of the project can also be the integration of the transmission and the final drive into a unit built in a single housing. Variability in size, torque and speed limitations allows to offer different customers a personalized solution.

Technical Specifications

Number of gears 2+N
Transmission ratio spread 3.9
Maximum input shaft torque up to 800 N*m
Maximum input shaft speed up to 4500 rpm
Maximum output shaft speed up to 8000 rpm
Maximum input shaft power 30-200 kW
Nominal efficiency 0.92
Shift control semi-automatic
Type of shifting mechanism drive electropneumatic
Type of cooling system air
1 up to 12
2 up to 3

Application

Advanced bus with electromechanical transmission

A modern bus with a hybrid or electric transmission with an electric motor-axle has high traction and dynamic characteristics, which are superior to buses with a mechanical transmission: rapid acceleration, maintaining a stable high speed while driving on the track by using a speed-increasing gear of the transmission, and using a speed-reducing gear while driving in the city at small speed and overcoming the hills.
The 2-speed transmission and electric motor can be used in various arrangement solutions of modern hybrid or electric trucks and buses.

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