PECULIARITIES OF THE DEVELOPMENT AND MANUFACTURING OF THE PROTOTYPE OF GAPLESS PLANETARY ROLLER SCREW MECHANISM

Author(s):  
D. S. Blinov ◽  
D. K. Dragun ◽  
A. S. Nosov

Known designs of gapless planetary roller screw mechanisms (PRSM) are highly accurate and rigid, but have low load capacity and short life. To eliminate these shortcomings, a new design of a gapless PRSM was developed and patented using a one-piece thin-walled nut. Due to radial deformation of the nut, the gaps between the threaded parts of the mechanism are chosen. The previous works have described the design of a new gapless PRSM and theoretically proved the possibility of a significant increase in load capacity and life using this mechanism. To confirm the theoretical results and conclusions, it is necessary to conduct experimental studies for which a prototype of the new gapless PRSM was made. The work presented describes a new technology for manufacturing threaded parts of this mechanism. In contrast to the traditional technology of grinding screw surfaces of the PRSM parts, which require special expensive equipment, it is proposed to grind and bore the screw surfaces of the parts with special plates on CNC turning machines. The metrological control has established that the dimensions of all parts of the prototype, including the threaded parts, did not go beyond the fields of the calculated or assigned tolerances.

2020 ◽  
Author(s):  
Nam Su Kim ◽  
Kyongho Kim ◽  
Sinhyok Jong

Abstract This paper aims to investigate the contact characteristics and static load carrying capacity of planetary roller screw mechanism (PRSM). Compared to the ball screw mechanism, the advantages of the PRSM are high stiffness, high load capacity, long travel life and compact structure, etc., since the PRSM possesses more contact points than ball screws in a comparable size. The actuated load is carried through the threaded surface contacts of the screw, the rollers and the nut and the contact characteristics of these components are very important for studying the wear, transmission accuracy and efficiency of a PRSM. Prior work has neglected to take a fundamental approach towards understanding the elastic-plastic contact characteristics of threaded surfaces under high loads and it is closely related to the static load carrying capacity of PRSM. Accordingly, in this paper, the contact characteristics of PRSM under the different working loads are modeled based on Hertz contact theory and the calculation formulas between normal force of thread turns and the elastic-plastic contact stress and deformation are derived. Then, it goes further to derive a calculation method of static load carrying capacity of PRSM based on simplified model of static load distribution. Finally, a verification model is developed by finite element method (FEM) to perform contact stress and strain analysis of PRSM. Besides, through the comparison of the results between the theory model and ANSYS Workbench finite element model verify the reliability of the theory.


Author(s):  
Xinhua Zhang ◽  
Xijian Huo ◽  
Jian Huang ◽  
Xiaoshuai Duan ◽  
Ping Guan ◽  
...  

Author(s):  
Hui Guo ◽  
Ruiting Tong ◽  
Geng Liu ◽  
Wenjie Zhang ◽  
Shangjun Ma

Based on the relationship between the load distribution and the load deformation of the thread of the planetary roller screw mechanism (PRSM), a modification method of the roller thread is proposed. The nut side and the screw side of the roller thread are modified by different amount of modification, and the modified thread load distribution is calculated and analyzed. The results show that the effects of roller thread modification on the load distribution are significant, and the sensitivity of the load capacity of the nut and screw to the modification is different. Through the study of the influence of roller thread modification on thread load distribution, the optimal value of the roller thread modification on the nut side and the screw side is obtained under the PRSM parameters given in this paper, which provides a theoretical guidance for the future PRSM load balancing design.


2016 ◽  
Vol 106 (05) ◽  
pp. 325-328
Author(s):  
C. Prof. Brecher ◽  
M. Fey ◽  
M. Hildebrand

Innerhalb der Rollengewindetriebe sind Planetenrollengewindetriebe aufgrund der sehr hohen Tragfähigkeit, Steifigkeit und Positioniergenauigkeit die am meisten verbreitete Bauart. Diesen Vorteilen steht eine bauartbedingte Einschränkung der realisierbaren Gesamtsteigung gegenüber. Es konnte anhand analytischer und experimenteller Untersuchungen gezeigt werden, dass sich diese Einschränkung durch eine Variation der Gewindegangzahlen der Spindel und der Mutter positiv beeinflussen lässt.   Due to the very high load capacity, rigidity and positioning accuracy, planetary roller screws are the most common type of roller screw drives. These advantages are contrasted by a limitation of total pitch caused by geometry parameters of this type. It was shown on the basis of analytical and experimental studies that this limitation can be positively influenced by a variation of the thread numbers of the spindle and the nut.


1980 ◽  
Vol 102 (1) ◽  
pp. 94-101 ◽  
Author(s):  
S. Okabe ◽  
Y. Yokoyama

This paper treats the motion of a particle on a vibratory feeder whose track has directional characteristic in repulsive motion, for examples, obliquely bristled track, obliquely sliced track and so on. Under some assumptions, the practical equation for predicting the mean conveying velocity is shown and the relations between conveying condition and the mean conveying velocity are clarified theoretically. These relations are shown in various diagrams. Referring these diagrams, the optimum conveying conditions are discussed also. The theoretical results show that the mean conveying velocity is considerably larger than that of the ordinary feeder. The theoretical results are confirmed by experimental studies.


Author(s):  
Yu Guo ◽  
Yu Hou ◽  
Qi Zhao ◽  
Xionghao Ren ◽  
Shuangtao Chen ◽  
...  

Foil bearing is considered to be a promising supporting technology in high-speed centrifugal machinery. Due to the high-speed shearing effect in the viscous lubricant film, heat generation could not be ignored. In this paper, a thermo-elastic model of the multi-leaf foil thrust bearing is proposed to predict its thermal and static characteristics. In the model, modified Reynolds equation, energy equation, and Kirchhoff equation are solved in a coupling way. The contact area between the foil and welding plate is taken into account. Besides, the effect of cooling air on the bearing temperature is investigated. The ultimate load capacity and transient overload failure process of the bearing is analyzed and discussed. The effect of rotation speed on the bearing temperature is more obvious than that of the bearing load. The bearing temperature drops obviously by introducing the cooling air, and the cooling effect is improved with the supply pressure. The transient overload failure of the bearing occurs when the bearing load exceeds the ultimate value.


10.12737/7168 ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 4-22 ◽  
Author(s):  
Анатолий Леонович ◽  
Anatoliy Leonovich ◽  
Виталий Мазур ◽  
Vitaliy Mazur ◽  
Даниил Козлов ◽  
...  

This article presents the review of experimental and theoretical studies on ultra-low-frequency MHD oscillations of the geomagnetic tail. We consider the Kelvin–Helmholtz instability at the magnetopause, oscillations with a discrete spectrum in the “magic frequencies” range, the ballooning instability of coupled Alfvén and slow magnetosonic waves, and “flapping” oscillations of the current sheet of the geomagnetic tail. Over the last decade, observations from THEMIS, CLUSTER and Double Star satellites have been of great importance for experimental studies. The use of several spacecraft allows us to study the structure of MHD oscillations with high spatial resolution. Due to this, we can make a detailed comparison between theoretical results and those obtained from multi-spacecraft studies. To make such comparisons in theoretical studies, in turn, we have to use the numerical models closest to the real magnetosphere.


2016 ◽  
Vol 19 (1) ◽  
Author(s):  
GEORGI GEORGIEV ◽  
NADEZHDA EVSTATIEVA

A comparative analysis has been carried out on two options of three-phase parametric current sources (inductive-capacitive stabilizers). Their capacities to operate in voltage stabilizer mode have been studied. Such capacities were proven and their conditions were defined. Theoretical results were experimentally checked and confirmed with satisfactory accuracy. Based on theoretical and experimental studies it was proven that the considered systems can operate in both modes – as current and voltage stabilizers.


Sign in / Sign up

Export Citation Format

Share Document