Reaction flywheel for the small spacecrafts

One of the main issues in the design of low-sized reaction flywheel was the selection of bearings, because there are strict limits on the size and weight of the device that allows using only ultra-light series of ball bearings. At the preliminary stage of design calculations verification of safety factors for loads in mechanical tests and of flexural strength of axis for mechanical testing identifying by critical sections was carried out. Rotor system of low-sized reaction flywheel consists of a flywheel mounted on the outer rings of ball bearings, inductors, and the rotor’s magnet of the rotor position sensor. The most dangerous moment is the unbalance of the rotor system as there is a direct link between the dynamic loads and the level of contact pressure between the bearing balls and raceways. Upon reaching significant values of these stresses flaking on the tracks and rolling elements is possible. Furthermore, the pressure unbalance inevitably causes the flywheel shaft of the friction force and hence heat, which leads to an increase in drag torque of the rotor, and also accelerates the aging process lubricant. In accordance with the general requirements imposed on the rotor system of low-sized reaction flywheel it was subjected to dynamic balancing, because only this type of balancing ensures the elimination of all types of unbalances with the required accuracy. To carry out this process step the rotor system has two correction planes located on the rim of the flywheel in the areas of maximum distance from the axis of rotation. Balancing is carried out by removing material in the areas of the annular grooves of the correction planes. Comparing the characteristics of low-sized reaction flywheel and foreign analogues shows that the parameters correspond to foreign models.