INFLUENCE OF MANUFACTURING ERRORS ON THE ACTUAL PROFILE OF THE ROLLER SCREW THREAD

This article described the structure and movement principle of planetary roller screw; established the equation of screw thread surface and roller surface, solved the meshing points of crossing thread engagement using numerical methods, while the screw and roller meshing at pitch diameter; studied meshing relationship between screw and roller comparing the distribution of simulated meshing point under various design parameters. The conclusion provides a theoretical basis for choosing parameters of planetary roller screw.

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An efficient method for analyzing the roller screw thread geometry

Mechanism and Machine Theory ◽

10.1016/j.mechmachtheory.2018.04.004 ◽

2018 ◽

Vol 126 ◽

pp. 243-264 ◽

Cited By ~ 6

Author(s):

Sebastian Sandu ◽

Nans Biboulet ◽

Daniel Nelias ◽

Folly Abevi

Keyword(s):

Efficient Method ◽

Screw Thread ◽

Roller Screw

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Kinematics of Planetary Roller Screw Mechanism considering Helical Directions of Screw and Roller Threads

Mathematical Problems in Engineering ◽

10.1155/2015/459462 ◽

2015 ◽

Vol 2015 ◽

pp. 1-11 ◽

Cited By ~ 9

Author(s):

Shangjun Ma ◽

Tao Zhang ◽

Geng Liu ◽

Ruiting Tong ◽

Xiaojun Fu

Keyword(s):

Numerical Simulation ◽

Numerical Model ◽

Analytical Model ◽

Analytical Solutions ◽

Simulation Method ◽

Screw Thread ◽

Numerical Simulation Method ◽

Roller Screw ◽

Screw Mechanism ◽

Planetary Transmission

Based on the differential principle of thread transmission, an analytical model considering helical directions between screw and roller threads in planetary roller screw mechanism (PRSM) is presented in this work. The model is critical for the design of PRSM with a smaller lead and a bigger pitch to realize a higher transmission accuracy. The kinematic principle of planetary transmission is employed to analyze the PRSM with different screw thread and roller thread directions. In order to investigate the differences with different screw thread and roller thread directions, the numerical model is developed by using the software Adams to validate the analytical solutions calculated by the presented model. The results indicate, when the helical direction of screw thread is identical with the direction of roller thread, that the lead of PRSM is unaffected regardless of whether sliding between screw and rollers occurs or not. Only when the direction of screw thread is reverse to the direction of roller thread, the design of PRSM with a smaller lead can be realized under a bigger pitch. The presented models and numerical simulation method can be used to research the transmission accuracy of PRSM.

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Kinematics of Roller Migration in the Planetary Roller Screw Mechanism

Journal of Mechanical Design ◽

10.1115/1.4006529 ◽

2012 ◽

Vol 134 (6) ◽

Cited By ~ 43

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.

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Microdensitometer—computer correlation analysis of ultrastructural periodicity

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081024 ◽

1978 ◽

Vol 36 (2) ◽

pp. 32-33

Author(s):

D.R. Ensor ◽

C.G. Jensen ◽

J.A. Fillery ◽

R.J.K. Baker

Keyword(s):

Correlation Analysis ◽

Background Noise ◽

Computer Control ◽

Optical Diffraction ◽

Screw Thread ◽

Straight Line ◽

Computer Storage ◽

Correlation Process ◽

Electron Microscope Image ◽

Fixed Beam

Because periodicity is a major indicator of structural organisation numerous methods have been devised to demonstrate periodicity masked by background “noise” in the electron microscope image (e.g. photographic image reinforcement, Markham et al, 1964; optical diffraction techniques, Horne, 1977; McIntosh,1974). Computer correlation analysis of a densitometer tracing provides another means of minimising "noise". The correlation process uncovers periodic information by cancelling random elements. The technique is easily executed, the results are readily interpreted and the computer removes tedium, lends accuracy and assists in impartiality.A scanning densitometer was adapted to allow computer control of the scan and to give direct computer storage of the data. A photographic transparency of the image to be scanned is mounted on a stage coupled directly to an accurate screw thread driven by a stepping motor. The stage is moved so that the fixed beam of the densitometer (which is directed normal to the transparency) traces a straight line along the structure of interest in the image.

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