In mechanical drives of machines there is a need to control changes in the speed of their actuators. Stepped and stepless gearboxes are used for this purpose. Known speed control devices have many disadvantages that adversely affect the durability and reliability of drive components and machines in general. These include the design complexity, high material consumption, automation complexity, dynamic loads during transitions from one speed to another, intensive wear of parts due to the friction connections use.
Aim. Development of a mathematical model of dynamic processes in speed change devices with multistage gear differential transmissions with closed-loop hydraulic systems on an example of a concrete design. Method. A device with a multistage differential has been considered, in which the gear wheel - the ring gear of the first stage is connected to the sun gear wheel of the second stage, the gear wheel - the ring gear of the second stage is connected to the sun gear wheel of the third stage, and so on, depending on the number of steps.
The article analyses the functioning of epicyclical gear train with closed circuit hydrosystem, where the driving element is the sun gear and driven one is the carrier or vice versa. Control element is the ring gear, which rotates or can be stopped by the closed circuit hydrosystem.
We have conducted a theoretical research of efficiency in such epicyclical gear train. Using the means of computer modelling, we have obtained graphical dependences of the transmission efficiency from its parameters.