Design of High Ratio Gear Reducer Using Vernier Differential Theory

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Jaehyeock Chang ◽  
Inbae Chang
Keyword(s):  
Static Analysis ◽  
High Ratio ◽  
Tooth Profile ◽  
Planetary Gears ◽  
Simple Mechanism ◽  
Involute Gear ◽  
Wide Range ◽  
Vernier Effect ◽  
Internal Gear

Abstract In this study, we propose a high ratio involute gear reducer using the Vernier effect, so-called Vernier drive. Our design consists of a fixed internal gear, a rotating internal gear, and single-profile planetary gears, which are mounted on a carrier and simultaneously mesh with both internal gears. Since the mechanism requires a design beyond the conventional gear meshing principles, a method to modify the tooth profile of the rotating internal gear is introduced and mathematically verified with exact geometric relations. The performance of the Vernier drive is theoretically studied by quasi-static analysis, and the operation is tested with additively manufactured prototypes. The results demonstrate that the Vernier drive is able to cover a wide range of reduction ratios with a simple mechanism.

scholarly journals Application of Dendrimers for Treating Parasitic Diseases

Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 343
Author(s):  
Veronica Folliero ◽  
Carla Zannella ◽  
Annalisa Chianese ◽  
Debora Stelitano ◽  
Annalisa Ambrosino ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Water Solubility ◽  
Parasitic Infection ◽  
Three Dimensional ◽  
Medical Knowledge ◽  
High Ratio ◽  
Molecular Volume ◽  
Parasitic Infections ◽  
Parasitic Diseases ◽  
Wide Range

Despite advances in medical knowledge, parasitic diseases remain a significant global health burden and their pharmacological treatment is often hampered by drug toxicity. Therefore, drug delivery systems may provide useful advantages when used in combination with conventional therapeutic compounds. Dendrimers are three-dimensional polymeric structures, characterized by a central core, branches and terminal functional groups. These nanostructures are known for their defined structure, great water solubility, biocompatibility and high encapsulation ability against a wide range of molecules. Furthermore, the high ratio between terminal groups and molecular volume render them a hopeful vector for drug delivery. These nanostructures offer several advantages compared to conventional drugs for the treatment of parasitic infection. Dendrimers deliver drugs to target sites with reduced dosage, solving side effects that occur with accepted marketed drugs. In recent years, extensive progress has been made towards the use of dendrimers for therapeutic, prophylactic and diagnostic purposes for the management of parasitic infections. The present review highlights the potential of several dendrimers in the management of parasitic diseases.

Research on S-gear design, manufacturing and measuring based on NC machining center

2020 ◽  
pp. 095440542098134
Author(s):  
Shao-ying Ren ◽  
Yan-zhong Wang ◽  
Yuan Li
Keyword(s):  
Convex Surface ◽  
Coordinate Measuring Machine ◽  
Nc Machining ◽  
Tooth Profile ◽  
Numerical Control ◽  
Machining Center ◽  
Involute Gear ◽  
Measuring Machine ◽  
Gear Contact ◽  
Nc Machining Center

This article presents a method of design, manufacturing, and measuring S-gear. S-gear is a kind of gear whose tooth profile is an S-shaped curve. The sine (cosine) gear, cycloid gear, polynomial gear, and circular arc gear are all S-gears in essence. In the S-gear transmission, the concave surface of one gear and the convex surface of the other gear contact each other. Therefore, the power transmitted by S-gear is much larger than that of the convex-convex-contact involute gear. Some scholars have studied the characteristics of S-gear, but few have explored its manufacturing. In this article, the Numerical Control (NC) machining technology of S-gear is studied in detail for its industrial application. The polynomial curve is used to construct the tooth profile of the S-gear based on the Gear Meshing Theory. The mathematical model of polynomial S-gear is established, by which involute gear can be represented as a special S-gear. The steps of generating NC codes are described. Then, the S-gear sample is processed with an NC machining center. Finally, the sample is measured with a Coordinate Measuring Machine (CMM), and the measurement results show that the accuracy of the S-gear processed by the NC machining center reaches ISO6. This research provides a feasible approach for the design, manufacturing, and measuring of S-gear.

scholarly journals Characterization and Applications of Diamond-like Nanocomposites: A Brief Review

2018 ◽  
Author(s):  
Kalyan Adhikary ◽  
Sayan Das ◽  
Debasish De ◽  
Anup Mondal ◽  
Utpal Gangopadhyay ◽  
...  
Keyword(s):  
Silicon Oxide ◽  
High Ratio ◽  
Atomic Scale ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Marine Energy ◽  
Deposition Parameters ◽  
Free Air ◽  
Wide Range ◽  
Scale Network

Diamond-like Nanocomposites (DLN) is a newly member in amorphous carbon (a:C) family. It consists of two or more interpenetrated atomic scale network structure. The amorphous silicon oxide (a:SiO) is incorporated within diamond-like carbon (DLC) matrix i.e. a:CH and both the network is interpenetrated by Si-C bond. Hence, the internal stress of deposited DLN film decreases remarkably compare to DLC. The diamond like properties has come due to deform tetrahedral carbon with sp3 configuration and high ratio of sp3 to sp2 bond. The DLN has excellent mechanical, electrical, optical and tribological properties. Those the properties of DLN could be varied over a wide range by changing deposition parameters, precursor and even post deposition treatment also. The range of properties are : Resistivity 10-4 to 1014 Ωcm, hardness 10–22 GPa, coefficient of friction 0.03-0.2, wear factor 0.2-0.4 10-7mm3/Nm, transmission Vis-far IR, modulus of elasticity 150-200 GPa, residual stress 200-300 Mpa, Dielectric constant 3-9 and maximum operating temperature 6000C in oxygen environment and 12000C in O2 free air. Generally, the PECVD method is used to synthesis the DLN film. The most common procedures used for investigation of structure and composition of DLN films are Raman spectroscopy, Fourier transformed infrared spectroscopy (FTIR), HRTEM, FESEM and X-ray photo electron spectroscopy (XPS). Interest in the coating technology has been expressed by nearly every industrial segment including automotive, aerospace, chemical processing, marine, energy, personal care, office equipment, electronics, biomedical and tool and die or in a single line from data to beer in all segment of life. In this review paper, characterization of Diamond-like Nanocomposites is discussed and subsequently different application areas are also elaborated.

Effect of tooth waist order parameters of double involute gears on lubrication performance of gear drive

2016 ◽  
Vol 68 (6) ◽  
pp. 671-675 ◽  
Author(s):  
Zhimin Fan ◽  
Wanfeng Zhou ◽  
Ruixue Wang ◽  
Na Wang
Keyword(s):  
Elastohydrodynamic Lubrication ◽  
Reference Value ◽  
Tooth Profile ◽  
Order Parameters ◽  
Content Type ◽  
Oil Film ◽  
Gear Drive ◽  
Involute Gear ◽  
Lubrication Performance ◽  
Involute Gears

Purpose The purpose of this paper is to derive a new lubrication model of double involute gears drive and study the effect of the tooth waist order parameters of double involute gears on lubrication performance. Design/methodology/approach The new lubrication model of double involute gears drive was established according to the meshing characteristics of double involute gears drive and the finite length line contact elastohydrodynamic lubrication theory. Numerical calculation of the lubrication model of gear drive was conducted using the multigrid method. Findings The results show that the oil film necking phenomenon and the oil film pressure peak emerged at the tooth waist order area and the tooth profile ends, and when compared with involute gear, the lubrication performance at the tooth waist order area is better than that at the tooth profile ends. The effect of tooth waist order parameters on lubrication performance at the tooth waist order area was greater than that at other areas. Originality/value This research will promote the application of the double involute gear as soon as possible, and it has the reference value for other types of gears.

Motion Simulation of Gears and Cams Using Working Model

1997 ◽  
Author(s):  
Shih-Liang Wang
Keyword(s):  
Complex Geometry ◽  
Gear Tooth ◽  
Tooth Profile ◽  
Line Contact ◽  
Motion Simulation ◽  
The Past ◽  
Working Model ◽  
Simulation Engine ◽  
Involute Gear ◽  
Involute Surface

Abstract Motion simulation of mechanism of line contact like gears and cams has been difficult in the past. With Working Model, NURBS based complex geometry can be modeled fairly easily, and its simulation engine can animate this type of mechanism accurately. In this paper several Working Model files are developed for visualization and analysis. An algorithm to generate involute gear tooth profile is introduced in this paper for the involute and a portion of non-involute surface.

Effect of Ratio of Liquid Pigment on Colouring Cement Matrix

2019 ◽  
Vol 296 ◽  
pp. 3-8
Author(s):  
David Bujdoš ◽  
Lucia Bulíková
Keyword(s):  
Colour Change ◽  
High Ratio ◽  
General Definition ◽  
Cement Matrix ◽  
Future Research ◽  
Colour Space ◽  
Cement Mortars ◽  
Wide Range ◽  
Definition Of ◽  
Cie Lab

Nowadays, the colouring is used in wide range of architectural concrete. Therefore, determination efficiency of pigments in case of particular combination of input materials is necessary. The research deals with influence of concentration of liquid inorganic pigments on the resulting colour of cement mortars. Two liquid pigments (yellow, red) were used for measurement purposes to verify their optimal ratio to achieve the best colouring of cement specimens. Pigments were mixed in the mortars of two types of cements used for architectural and decorative design. The colour change was determined using Konica Minolta spectrophotometer in colour space CIE Lab (1976). General definition of deviation in the colour space ΔELab was applied for calculating of colour deviation. From the results of the laboratory tests is obvious that significant change of the colour of cement specimens do not show between the concentration of 6% and 9% of the pigment per cement weight yet. Consequently, using of high ratio of pigment than 9% is not profitable neither for purchaser, nor builder. Future research will focus on trials with a more elaborate share of pigment and it will have importance for price optimization in the construction industry.

Rating Gear Strength

1981 ◽  
Vol 103 (2) ◽  
pp. 516-527 ◽  
Author(s):  
G. Castellani ◽  
V. P. Castelli
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Gear Tooth ◽  
Correction Factors ◽  
Iso Standards ◽  
Gear Teeth ◽  
Root Parameters ◽  
Involute Gear ◽  
Tooth Form ◽  
Internal Gear

Synthetic formulas are written suitable to represent and compare the AGMA and ISO Standards for rating gear tooth strength. The corresponding tooth form and stress correction factors are compared for different kinds of involute gear teeth. A unified procedure is given to enable computing of the root parameters for teeth generated by any kind of tool which completes the ISO method, extending it to the case of shaped teeth. Both AGMA and ISO methods are also applied to the calculation of the aforesaid factors for internal gear teeth. In this case reliability is checked by finite element method. The comparison shows that research is necessary to review some items relating to calculation of stress correction factors.

Optimization of Profile Modifications With Regard to Dynamic Tooth Loads in Single and Double-Helical Planetary Gears With Flexible Ring-Gears

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
M. Chapron ◽  
P. Velex ◽  
J. Bruyère ◽  
S. Becquerelle
Keyword(s):  
Equations Of Motion ◽  
Integration Scheme ◽  
Time Varying ◽  
Time Step ◽  
Planetary Gears ◽  
Contact Algorithm ◽  
Beam Elements ◽  
Internal Gear ◽  
Gear Meshes ◽  
Optimum Profile

This paper is mostly aimed at analyzing optimum profile modifications (PMs) in planetary gears (PGTs) with regard to dynamic mesh forces. To this end, a dynamic model is presented based on 3D two-node gear elements connected to deformable ring-gears discretized into beam elements. Double-helical gears are simulated as two gear elements of opposite hands which are linked by shaft elements. Symmetric tip relief on external and internal gear meshes are introduced as time-varying normal deviations along the lines of contact and time-varying mesh stiffness functions are deduced from Wrinckler foundation models. The equations of motion are solved by coupling a Newmark time-step integration scheme and a contact algorithm to account for possible partial or total contact losses. Symmetric linear PMs for helical and double-helical PGTs are optimized by using a genetic algorithm with the objective of minimizing dynamic tooth loads over a speed range. Finally, the sensitivity of these optimum PMs to speed and load is analyzed.

Ambulance Stretcher Suspensions

1985 ◽  
Vol 199 (2) ◽  
pp. 151-160 ◽  
Author(s):  
C W Stammers ◽  
D Leysbon
Keyword(s):  
Natural Frequency ◽  
Vibration Isolation ◽  
Coil Spring ◽  
Electric Actuator ◽  
Initial Testing ◽  
Load Variation ◽  
Simple Mechanism ◽  
Wide Range ◽  
Patient Load

Existing methods for vibration isolation of patients transported by ambulance are discussed. Some alternative suspensions are outlined and a relatively simple mechanism analysed. This can give virtually constant vertical natural frequency over a wide range of patient load. Variation in pitch natural frequency can also be minimized at the expense of some variation in vertical natural frequency. The elements used are a coil spring, load arm and an electric actuator. Initial testing of the mechanism has been made to confirm the feasibility of the concept.

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