Frictional steering devices in two-flow transmissions of transport caterpillar vehicles
The problem of quality of management of turn is the general for tracked vehicles of different function, especially for high-speed transport vehicles. Usually, this problem is solved application of two-flow transmission with use of hydrostatic gear in a parallel flow of power with the transforming mechanism (the central or onboard gearboxes). In the article is offered to use the frictional steering device as a part of the closed-loop (servo) control system as an alternative to hydrostatic gear. To control over effort of compression and, respectively, slipping of disks of the frictional steering device applies the principle of pulse-width modulation of power pressure. Assessment of power dissipation capability on the slipping element of management of the frictional steering device installed in transmission of the tracked vehicle with onboard gearboxes weighing 42 tons is carried out. It is established that at the most probable turning radius power dissipation capability doesn't exceed 50 kW. Besides, in article kinematic schemes of the one-stage and two-level frictional steering device are provided. The one-stage frictional steering device was tested on ride tests of the tracked vehicle with onboard gearboxes, its application is limited to one rated turning radius and high loading of frictional elements. Use of the two-level steering device will allow to reduce wear of disks of elements of management and smoother turn, in comparison with one-stage, but will complicate a design a little. The scheme of two-line transmission with the central gearbox is also provided. It is expected that the power disseminated on the frictional steering device will be higher, than when using in transmission with onboard gearboxes. Thus, calculations and tests show that frictional steering devices are capable to replace hydrostatic gear in the steering device of the tracked vehicle, especially in the conditions of dense configuration of transmission department where other options are still impossible.