scholarly journals PERFORMANCE INDICATORS OF CONCHOIDAL STRAIGHT SPUR GEARS WITH INCREASED LOADING CAPACITY. THE THEORY

2021 ◽  
pp. 85-93
Author(s):  
Pavlo Tkach ◽  
Pavlo Nosko ◽  
Oleksandr Bashta ◽  
Grygorii Boiko ◽  
Olha Herasymova
Keyword(s):  
Performance Indicators ◽  
Experimental Tests ◽  
Maximum Load ◽  
Spur Gears ◽  
Surface Strength ◽  
Actual Problem ◽  
Reference Profile ◽  
Meshing Characteristics ◽  
Machine Drives ◽  
Gear Drives

The article is devoted to the actual problem of increasing the performance indicators of machine gear drives. To solve this problem, in the article proposed to use a conchoidal engagement made with a shifting of the  reference profile and special contact conditions. A feature of the proposed engagement is that it is less sensitive to manufacturing and assembly errors compared to conventional conchoidal engagement. As a result of theoretical studies, the performance indicators of such an engagement were determined. This made it possible to determine the level of load during further experimental tests of new gears. Contact strength and meshing losses were selected as performance indicators subject to further experimental verification. The ratios of these indicators, calculated for conchoidal spur gears with convex-convex contact, made with a shifting of the reference profile, with similar involute ones, are theoretically determined. Comparative analysis of performance indicators was carried out for gears of involute and conchoidal engagement with the same parameters and shifting of the reference profile. It was found that for experimental conchoidal drives with shifting, the maximum load is 1.2 times higher than that of a similar involute drive with shifting, and the loss in engagement is 21% less. A rational area of application of the new gearing is machine drives for high power transmissions. Keywords: spur gears, conchoidal gearing, profile shift, convex-convex contact, meshing characteristics, teeth surface strength, gearing power loss

An improved model for meshing characteristics analysis of spur gears considering fractal surface contact and friction

2021 ◽  
Vol 158 ◽  
pp. 104219
Author(s):  
Zhifang Zhao ◽  
Hongzheng Han ◽  
Pengfei Wang ◽  
Hui Ma ◽  
Shunhao Zhang ◽  
...  
Keyword(s):  
Spur Gears ◽  
Fractal Surface ◽  
Surface Contact ◽  
Characteristics Analysis ◽  
Meshing Characteristics ◽  
Improved Model

scholarly journals Monitoring of the load regime applied on the osseointegrated fixation of a trans-femoral amputee: A tool for evidence-based practice

2008 ◽  
Vol 32 (1) ◽  
pp. 68-78 ◽  
Author(s):  
Laurent Frossard ◽  
Nathan Stevenson ◽  
James Smeathers ◽  
Eva Häggström ◽  
Kerstin Hagberg ◽  
...  
Keyword(s):  
Performance Indicators ◽  
Daily Living ◽  
Evidence Based Practice ◽  
Maximum Load ◽  
The Body ◽  
Evidence Based ◽  
Data Logger ◽  
Actual Usage ◽  
Load Regime ◽  
User Friendly

This study aimed to provide a description of the continuous recording of the true load regime experienced during daily living by the abutment of a trans-femoral amputee fitted with an osseointegrated fixation. The specific objectives: (i) To present an apparatus and a procedure allowing recording of the load regime, and (ii) an example of the raw data and six performance indicators of the usage of the prosthesis obtained with this method. A subject was monitored for a period of 5 hours as he went about his daily activities. The load regime was directly measured and recorded using a commercial transducer and data logger. The overall load profile presented alternative periods of variable length of inactivity (64%) and activity (36%), respectively. The maximum load applied on the mediolateral, anteroposterior and the long axes represented 21%, 21% and 120% of the body weight, respectively. The anteroposterior, mediolateral and long components of the impulse were 395 kN.s, 359 kN.s and 2,323 kN.s, respectively. The amputee generated a total of 2312 gait cycles of the prosthetic leg, giving an approximate overall cadence of 8 stride/min. Preliminary outcomes indicated that the proposed method was an improvement on the current techniques as it provided the true loading and actual usage of the prosthesis during daily living. This study is a stepping stone in the development of future affordable, on-board and user-friendly load recording systems that can be used in evidence-based practice.

A Standing Wave Piezoelectric Ultrasonic Motor Using a Single Flexural Vibration Ring Transducer

2013 ◽  
Vol 415 ◽  
pp. 126-131
Author(s):  
M. Shafik ◽  
L. Makombe
Keyword(s):  
Standing Wave ◽  
Flexural Vibration ◽  
Experimental Tests ◽  
Maximum Load ◽  
Ultrasonic Motor ◽  
Housing Unit ◽  
Element Analysis ◽  
Design Structure ◽  
Piezoelectric Ultrasonic Motor ◽  
Working Parameters

This paper presents a rotary standing wave ultrasonic motor using single flexural vibration ring transducer. The motor consists of three main components, the stator, rotor and housing unit. The stator is a piezoelectric transducer ring. The rotor is designed of a compact driving wheel and shaft. The housing unit is made of a transparent thermoplastic Perspex material and is part of the motor working mechanism. The motor design, structure, working principles and modelling using finite element analysis is discussed and presented in this paper. A prototype of the motor was fabricated and its characteristics measured. Experimental tests showed that the motor electrical working parameters are: Current: 100 m-amps, Voltage: 100 volts, Frequency: 41.7 kHz, typical speed of 32 revolutions per minute, a resolution of less than 50μm and maximum load of 1.5 Newton.

scholarly journals COMPARISON OF SINUSOIDAL AND INVOLUTE SPUR GEARS BY MESHING CHARACTERISTICS

2019 ◽  
Vol 1 (57) ◽  
pp. 41-51
Author(s):  
P. Tkach ◽  
◽  
P. Nosko ◽  
O. Bashta ◽  
Yu. Tsybrii ◽  
...  
Keyword(s):  
Spur Gears ◽  
Meshing Characteristics

scholarly journals MODIFICATIONS OF GEAR WHEEL TEETH OF AVIATION GEARBOXES TO INCREASE THEIR OPERATIONAL RELIABILITY AND TECHNOLOGY

2021 ◽  
pp. 112-125
Author(s):  
O. Pilipenko ◽  
D. Kolesnik ◽  
A. Berezniak ◽  
R. Kholodnyi
Keyword(s):  
Contact Zone ◽  
Gear Wheel ◽  
Operational Reliability ◽  
Spur Gears ◽  
Operational Characteristics ◽  
Significant Difference ◽  
Different Types ◽  
Gear Wheels ◽  
Gear Drives ◽  
Radical Type

The types and methods of modifications of teeth and gear wheels, which have found application in gearboxes of aircraft and helicopters, are presented. Features of geometry, parameters of different types of initial produced contours, their modifications, application and influence of various factors on improving the operational characteristics of gear drives of aviation gearboxes are considered. Arcuate (short and long) and short linear options for modifying the tooth profiles of aircraft gearboxes are best suited to absorb the errors of spur gears. There was no significant difference in the use of short and long correction for a relative decrease in temperature in the contact zone of the wheel teeth, therefore, the use of any correction of the tooth profile, with rare exceptions, turns out to be useful. The advantages of using increased profile angles in comparison with the standard ones used in general mechanical engineering are considered. Development of designs of teeth and gear wheels in aircraft gearboxes, the use of gears with teeth of an asymmetric profile, which can be considered as a cardinal modification of the tooth profiles. The use of such gears increases the strength of the teeth due to the increase in the thickness of the teeth. Unsymmetrical teeth have a large thickness at the tip, which reduces teeth chipping and due to their greater height, greater smoothness of engagement is achieved, bending and contact stresses are reduced. The most radical type of modification is the use of asymmetric profiles of the teeth of the wheels of aircraft gearboxes.

Determination of Addendum Modification Coefficients for Spur Gears Operating at Non-Standard Center Distances

2003 ◽  
Author(s):  
M. A. Sahir Arikan
Keyword(s):  
Gear Tooth ◽  
Gear Ratio ◽  
Spur Gears ◽  
Contact Ratio ◽  
Performance Variables ◽  
Practical Design ◽  
Gear Drives ◽  
Maximum Contact ◽  
Center Distance

Although it is possible to find some recommended conventional values both for the sum of the addendum modification coefficients and for the allocation of the sum of the addendum modification coefficients (e.g. ISO/TR 4467), a detailed analysis is necessary to determine the addendum modification coefficient values for the desired optimization criteria and the performance since the main objective of the above mentioned sources is to facilitate practical design of non-standard gear drives which will not have problems while operating. They give practical average values within a safe range. In this study, by considering the required gear ratio, center distance and the desired backlash, alternative gear pairs are determined and corresponding gear performance variables are calculated in order to allocate the addendum modification coefficients for the pinion and the gear by using criteria such as: not having undercut or pointed (or excessively-thinned-tip) tooth, having desired proportions for the lengths of the dedendum and addendum portions of the line of action, having maximum contact ratio, having sufficient bottom clearance, having minimum contact stresses, having balanced pinion and gear tooth root stresses, having equal pinion and gear lives, etc.

The Changing Law of Tooth Bending Stress for Herringbone Gears with High Contact Ratio

2010 ◽  
Vol 139-141 ◽  
pp. 965-969 ◽  
Author(s):  
Le Hao Chang ◽  
Geng Liu
Keyword(s):  
Maximum Stress ◽  
Bending Strength ◽  
Maximum Load ◽  
Spur Gears ◽  
Bending Stress ◽  
Contact Ratio ◽  
Load Distributions ◽  
Generating Method ◽  
Definition Of ◽  
Herringbone Gear

From the principle of generating method, the precise model of an involute herringbone gear was built. The accurate load distributions of herringbone gear were obtained in different meshing positions in linear programming method. Then the changing course of root bending stress along with the variation of meshing position was gained. The calculation process realized the automatic definition of loads and boundary conditions, and found out the value and the position when the tooth root has maximum bending stress. The results showed that the maximum stress usually appears near the position when the tooth bears maximum load. Be different from spur gears, the maximum stress of herringbone gears will possibly appear in the section where more teeth couples are engaged. The analysis can effectively provide reference for checking tooth bending strength of herringbone gears.

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