Vibration decrease of electromechanical actuators based on roller screw mechanisms

Abstract

Abstract. The reduction of the vibratory activity of the roller screw mechanism (RSM) for converting a rotational movement into a translational movement is discussed. A mathematical model of vibratory activity roller screw mechanisms on the basis of elastic compliances was developed. The resulting equation for calculating the natural frequencies of the basic RSM elements -screw, rollers and nut was obtained. It is proved that the RSM has a low vibroactivity that allows you to create mechatronic actuators, the maximum level of vibration does not exceed 60 to 62 dB, which is 11-16 dB below the level of vibratory activity gear mechanisms IntruductionRecently, planetary roller-screw mechanisms (RSM) have become widely used among executive mechanisms used for converting rotary movement into linear displacement [1][2][3][4][5][6]. In papers [2, 3, 6] we have shown methods for calculating the main technical characteristics of those mechanisms. At the same time, an important actuators characteristic, often determining the applicability of a particular mechanism, is its vibroactivity and, as a result, the noise generated. The screw gear smoothness is the cause of decreased RSM vibroactivity and noise and makes those mechanisms promising for use. As for RSM, the closest analogues for the design models are planetary gear mechanisms [4,5] and rolling bearings [6,7] which vibrational processes have been studied sufficiently. However, the use of calculation procedures developed here and practical recommendations for the RSM vibrations reduction is unjustified, because of the changing characteristics and difference between screw mechanisms [8,9]. Let us consider the mechanism option where the screw-rollers support interface is made with multistart threads and has end-capping geared rims. The mechanism structure (Fig.1) comprises screw 1 installed in bearings fixed in housing 2. On the screw and rollers geared rims 6 were cut. The screw is mating the thread rolls 3 through the thread and through the gear rims 6, and the rollers interact with the nut 4 thread. The casing is fixed to the base 5. The problems solved during RSM vibroactivity study are as follows: determining vibration sources, their frequencies and amplitudes, calculating the forced vibrations spectrum, determining the audio range vibration levels accounted for by the RSM casing. Materials and methodsOut of the many oscillation theory methods, the most suitable method for solving the tasks in hand is the dynamic compliance method. The method is as follows. The mechanism is divided into a number of simple subsystems. As for the RSM the following subsystems are distinguished: screw, rollers, nuts and housing (Fig. 2). 1 -screws and clips; 2 -roller and nuts; 3 -screw and toothed roller in the circuit; 4 -screw-on body X axis; 5 -the screw-on housing axis Y; 6 -the screw-on housing axis Z; 7 -a nut body on X-axis; 8 -a nut body on Y-axis; 9 -key -keyway; 10 -body-reliance on the X axis; 11 -body-reliance on the Y axis; 12 -body-reliance on the Z axis; 13 -body-suppor...

Dynamics of the Vibro-Impact Nonlinear Damped and Forced Oscillator under the Influence of the Electromagnetic Actuation

“…Morozov et al [16] discussed the diminution of the vibratory activity of a roller screw mechanism for converting a rotational movement into a translational one. It was proved that this mechanism has a low vibroactivity that leads to create mechatronic actuators.…”

Lagrange-method-based dynamic analysis of multi-stage planetary roller screw mechanism

“…According to the bond-graph formalism, Karm et al (2009) developed a simplified dynamic model of the inverted PRSM and integrated it into a model of electromechanical actuator. Considering the elastic contacts between parts, Morozov et al (2017) proposed a dynamic model of the PRSM to calculate the natural frequencies of the mechanism and a linear electromechanical actuator with the PRSM. Ma et al (2017) proposed a dynamic model of PRSM based on the bond graph theory that accounts for friction forces, axial clearances, and the stiffness of the screw.…”

Control of mechatronic drives considering the type and number of the nonlinearities of a mechanical converter

“…The concept of designing an electromechanical drive as a single mechatronic device is widely known and has been realized during the creation of a mechatronic single-block drive, that is a whole structure based on a contactless torque motor to the hollow rotor built with a planetary screw or roller screw mechanism which provides either a linear or rotational output motion Fig. 1 [1][2][3][4]. The software implementation and hardware execution of the motion controller by the drives largely determine the quality of the output motion [5][6][7][8].…”

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