Kinematics of Roller Migration in the Planetary Roller Screw Mechanism

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Matthew H. Jones ◽  
Steven A. Velinsky
Keyword(s):  
Slip Velocity ◽  
Kinematic Model ◽  
Helical Gear ◽  
Orbital Mechanics ◽  
Ring Gear ◽  
Manufacturing Errors ◽  
Roller Screw ◽  
Screw Mechanism ◽  
The Given

This paper develops a kinematic model to predict the axial migration of the rollers relative to the nut in the planetary roller screw mechanism (PRSM). This axial migration is an undesirable phenomenon that can cause binding and eventually lead to the destruction of the mechanism. It is shown that this migration is due to slip at the nut–roller interface, which is caused by a pitch mismatch between the spur-ring gear and the effective nut– roller helical gear pairs. This pitch circle mismatch can be due to manufacturing errors, deformations of the mechanism due to loading, and uncertainty in the radii of contact between the components. This paper derives the angle through which slip occurs and the subsequent axial migration of the roller. It is shown that this roller migration does not affect the overall lead of the PRSM. In addition, the general orbital mechanics, in-plane slip velocity at the nut–roller interface, and the axial slip velocities at the nut–roller and the screw–roller interfaces are also derived. Finally, an example problem is developed using a range of pitch mismatch values for the given roller screw dimensions, and the axial migration and slip velocities are determined.

Dynamics of the Planetary Roller Screw Mechanism

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Matthew H. Jones ◽  
Steven A. Velinsky ◽  
Ty A. Lasky
Keyword(s):  
Steady State ◽  
Slip Velocity ◽  
Equations Of Motion ◽  
Viscous Friction ◽  
Contact Angles ◽  
Dynamic Equations ◽  
Roller Screw ◽  
Angular Velocities ◽  
Screw Mechanism ◽  
Lagrange’S Method

This paper develops the dynamic equations of motion for the planetary roller screw mechanism (PRSM) accounting for the screw, rollers, and nut bodies. First, the linear and angular velocities and accelerations of the components are derived. Then, their angular momentums are presented. Next, the slip velocities at the contacts are derived in order to determine the direction of the forces of friction. The equations of motion are derived through the use of Lagrange's Method with viscous friction. The steady-state angular velocities and screw/roller slip velocities are also derived. An example demonstrates the magnitude of the slip velocity of the PRSM as a function of both the screw lead and the screw and nut contact angles. By allowing full dynamic simulation, the developed analysis can be used for much improved PRSM system design.

Kinematic Model of Planetary Roller Screw Mechanism With Run-Out and Position Errors

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Xiaojun Fu ◽  
Geng Liu ◽  
Shangjun Ma ◽  
Ruiting Tong ◽  
Teik C. Lim
Keyword(s):  
Rigid Body ◽  
Body Movement ◽  
Kinematic Model ◽  
Rotation Period ◽  
Fundamental Property ◽  
Transmission Error ◽  
Position Errors ◽  
Proposed Model ◽  
Roller Screw ◽  
Screw Mechanism

A kinematic model of the planetary roller screw mechanism (PRSM) is proposed, which accounts for the run-out errors of the screw, roller, nut, ring gear, and carrier, and the position errors of the nut and the pinhole in the carrier. The roller floating region, which contains all the possible positions of the roller inside the pinhole, is obtained by analyzing the axial clearances between mating thread surfaces and the radial clearance between the roller and carrier. The proposed model is based on the constraint that the set of roller floating region is not empty. Then, the additional rigid-body movement on the nut is derived and the path of motion transfer from the screw to the nut is obtained. According to the fundamental property of rigid-body kinematics, the axial velocity of the nut is derived and the transmission error of the PRSM is calculated. The proposed model is verified by comparing the calculated transmission error with experimental one. The results show that the transmission error of the PRSM with run-out and position errors is cyclic with a period corresponding to the rotation period of the screw and the magnitude of the transmission error can be much larger than the lead error of the screw. Besides, due to the run-out and position errors, the roller can move radially or transversally inside the pinhole of the carrier when the elements in the PRSM are regarded as rigid bodies.

Dynamic Modeling of the Double-Nut Planetary Roller Screw Mechanism Considering Elastic Deformations

2021 ◽  
Author(s):  
Xiaojun Fu ◽  
Geng Liu ◽  
Xin Li ◽  
Ma Shangjun ◽  
Qiao Guan
Keyword(s):  
External Force ◽  
Load Distribution ◽  
Equations Of Motion ◽  
Great Influence ◽  
Compressive Force ◽  
Mass System ◽  
Elastic Deformations ◽  
Roller Screw ◽  
Screw Mechanism ◽  
Nonlinear Equations Of Motion

Abstract With the rising application of double-nut Planetary Roller Screw Mechanism (PRSM) into industry, increasing comprehensive studies are required to identify the interactions among motion, forces and deformations of the mechanism. A dynamic model of the double-nut PRSM with considering elastic deformations is proposed in this paper. As preloads, inertial forces and elastic deformations have a great influence on the load distribution among threads, the double-nut PRSM is discretized into a spring-mass system. An adjacency matrix is introduced, which relates the elastic displacements of nodes and the deformations of elements in the spring-mass system. Then, the compressive force acting on the spacer is derived and the equations of load distribution are given. Considering both the equilibrium of forces and the compatibility of deformations, nonlinear equations of motion for the double-nut PRSM are developed. The effectiveness of the proposed model is verified by comparing dynamic characteristics and the load distribution among threads with those from the previously published models. Then, the dynamic analysis of a double-nut PRSM is carried out, when the rotational speed of the screw and the external force acting on the nut #2 are changed periodically. The results show that if the external force is increased, the preload of the nut #1 is decreased and that of the nut #2 is increased. Although the nominal radii of rollers are the same, the maximum contact force acting on the roller #2 is much larger than that of the roller #1.

Elasto-plastic contact characteristics of the Planetary Roller Screw Mechanism

2016 ◽  
pp. 181-186
Author(s):  
R.T. Tong ◽  
H. Guo ◽  
G. Liu ◽  
Q. Yao
Keyword(s):  
Roller Screw ◽  
Screw Mechanism

Investigation on the uncertain factors of the elastic–plastic contact characteristics of the planetary roller screw mechanism

2018 ◽  
Vol 233 (5) ◽  
pp. 1795-1806
Author(s):  
Qin Yao ◽  
Yongshou Liu ◽  
Mengchuang Zhang ◽  
Geng Liu ◽  
Shangjun Ma
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Mathematic Model ◽  
Contact Analysis ◽  
Secondary Development ◽  
Elastic Plastic ◽  
Development Platform ◽  
Roller Screw ◽  
Screw Mechanism ◽  
Element Method

The scatter of uncertain factors of the planetary roller screw mechanism, which originated from the manufacturing process, has a significant influence on its serving performance. However, this influence remains insufficiently studied. Further, the elastic–plastic contact analysis of the planetary roller screw mechanism with considering the uncertainties needs large numbers of repetitive calculations by traditional finite element method, which is labor intensive and often impractical. In this paper, an uncertain model of the planetary roller screw mechanism, including parameterization and finite element calculation, is established to conduct the elastic–plastic contact analysis automatically. Besides, the finite element method results can be also obtained automatically with the self-compiled flow program and the secondary development platform using the design of experiment method. Then, a mathematic model is applied to value the influence of the uncertain factors on the contact characteristics. The Pareto graphs are plotted to clearly show this sequence of the percent effects of all the uncertain factors. The present work, for the first time, developed an automatic modeling method for analyzing efficiently the uncertain factors of planetary roller screw mechanism, which is worthy in industrial application.

scholarly journals Modelling of Electro-mechanical Servo System Based on the Planetary Roller Screw Mechanism

2020 ◽  
Vol 306 ◽  
pp. 02004
Author(s):  
Jianxin Zhang ◽  
Chuanming Du ◽  
Shangjun Ma ◽  
Geng Liu
Keyword(s):  
Contact Stiffness ◽  
Servo System ◽  
Response Speed ◽  
Load Force ◽  
System Response ◽  
Analysis Model ◽  
Roller Screw ◽  
Fluctuation Amplitude ◽  
Screw Mechanism ◽  
Main Components

Taking the electro-mechanical servo system as the research object, considering the contact stiffness, friction and clearance of the main components in the electro-mechanical servo system, the analysis model of the electro-mechanical servo system based on Planetary roller screw mechanism (PRSM) is established by using AMESim software. The results showed that the response speed of the system slowed down when the friction of PRSM was taken into account. The larger the clearance or the smaller the stiffness, the greater the fluctuation amplitude of the system response. After the controller was adjusted, the steady-state error of the system caused by the load force can be reduced quickly.

Thermal characteristics analysis and experimental study of the planetary roller screw mechanism

2019 ◽  
Vol 149 ◽  
pp. 1345-1358 ◽  
Author(s):  
Guan Qiao ◽  
Geng Liu ◽  
Shangjun Ma ◽  
Yawen Wang ◽  
Pin Li ◽  
...  
Keyword(s):  
Experimental Study ◽  
Thermal Characteristics ◽  
Characteristics Analysis ◽  
Roller Screw ◽  
Screw Mechanism
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