A Frictional Heat Model of Planetary Roller Screw Mechanism Considering Load Distribution

Abstract

Planetary roller screw (PRS), with higher thrust, higher load capacity, and higher speed, is the best choice of the transmission component of the servo system. However, spinning sliding of rollers and support bearings can cause frictional moments and frictional heat, which is an undesirable phenomenon. Besides, frictional heat will further result in high temperature that causes deterioration of lubrication and eventually lead to destruction of the mechanism. Therefore, it is important to predict frictional moments which result in frictional heat. In order to predict the magnitude of frictional heat of PRS mechanism and study the influence of structural parameters of thread and operating conditions on frictional heat, first, a frictional moment model of bearings is built, and frictional moments models of PRS considering the elastic hysteresis of material, the spinning sliding of the rollers, the viscosity of lubricating oil and the differential sliding of thread raceways are established in this paper, respectively. Second, heat generation models of bearing and PRS are presented, respectively. Finally, relationships between frictional heat in terms of operating conditions of PRS, contact angle, and helix angle of roller thread are investigated. The achievements of this project will provide theoretical basis for the design of PRS with lower frictional moments and higher transmission efficiency.

Thermo-Mechanical Model and Thermal Analysis of Hollow Cylinder Planetary Roller Screw Mechanism

“…The total frictional moments of the PRSM consist of the frictional moments caused by preload and the frictional resistance moments caused by movement of components. The heat generated by the PRSM was defined as (Ma et al, 2015):…”

“…Li et al (2012) proposed a theoretical temperature model based on heat conduction equation of the screw and the modified boundary value conditions. The aim of this paper is to extend our previous research on frictional heat model of PRSM considering load distribution (Ma et al, 2015) to establish a FEMbased thermo-mechanical model for a preloaded hollow cylinder PRSM system. Temperature distribution and thermal error of screw shaft caused by two heat sources are investigated.…”

“…Extremely small leads were easily obtained. A reliable frictional heat model of PRSM considering load distribution is developed by Ma et al (2015) to precisely predict the quantity of frictional heat and thoroughly study the influences of structure parameters of thread on frictional heat. Dynamic responses, frictional characteristics and contact slip were systematically studied.…”

Planar roller chain drive dynamics using a cylindrical contact force model

“…Aspects such as the compliance of the matting contact surfaces, as in roller screw mechanisms (Jones and Velinsky 2013), or the frictional heat due to the contact within such mechanisms (Ma et al 2014), exemplify cases in which the normal and tangent forces in the contact mechanics are required. Dynamic models to represent such non-ideal characteristics constitute challenges to find new and better machine designs.…”

Thermo-mechanical coupling–based finite element analysis of the load distribution of planetary roller screw mechanism

“…In recent years, many studies have been published that support the engineering applications of PRSMs, such as kinematic modeling and analysis, 2-5 the meshing mechanism, 6,7 rolling-sliding friction, 8,9 frictional heat and thermal analysis, 10,11 and dynamics of PRSMs. 12 Importantly, the load distribution over the threads of the screw, roller, and nut is another important research field, which is the basis for studying the carrying capacity, durability and stiffness, and so on.…”