Determination of the Friction Work of a Link Chain Interworking with a Sprocket Drum / Wyznaczenie Pracy Tarcia Łańcucha Ogniwowego We Współdziałaniu Z Bębnem Łańcuchowym

2013 ◽  
Vol 58 (3) ◽  
pp. 805-822 ◽  
Author(s):  
Piotr Sobota
Keyword(s):  
Abrasive Wear ◽  
Friction Couple ◽  
Tooth Flank ◽  
Relative Friction

Abstract The significant abrasive wear of sprocket drum teeth and seats bottoms is observed during the exploitation of longwall scraper conveyors. For this reason, it is important to determine friction work in sliding conditions of the horizontal link on the tooth seat bottom and on the tooth flank and friction work in the joint of links in the context of such nodes’ abrasive wear. The different construction variants of sprocket drums can be compared by determining friction work in the sliding positions of the horizontal link on the drum. The determination of the losses of the power transmitted is a requisite condition in such situation for determining the efficiency values of chain meshing. The friction work of the friction couple of a sprocket drum - link chain consists of friction work of the horizontal link in the places where it contacts with the seat bottom Ag and the tooth flank Af and friction work in the joints of a horizontal link in the contact place with vertical links: in the front joint Ap and the rear joint At. The article presents dependencies enabling to determine the value of such work for specific geometric relations between the chain and the drum and different friction conditions. The curves of relative friction work and the values of total friction work on the seat bottom, on the tooth flank and in a front and rear joint of links are presented for examples of friction conditions.

scholarly journals Comparison of Conventional Sprocket Drum and Sprocket Drum with Modified Design

2016 ◽  
Vol 61 (3) ◽  
pp. 509-522
Author(s):  
Piotr Sobota
Keyword(s):  
Occurrence Probability ◽  
General Direction ◽  
Friction Path ◽  
The Asymmetry ◽  
Proposed Modification ◽  
Tooth Flank ◽  
Relative Friction

Abstract Seats in conventional sprocket drums are symmetrical. Due to the set general direction of sprocket drum revolutions resulting from the direction of rock transport, the wear of the seat bottoms and teeth flanks may be reduced by introducing the asymmetry of the profile of the sprocket drum seats. The proposed modification of sprocket drum seats’ profile consists of inclining the seat bottom towards the expected direction of the basic drum revolutions. The work compares the loads on the seats and teeth of a conventional drum with its profile conforming to the standard to a modified drum with an asymmetric profile of seats. For the general direction of sprocket drum revolutions, the maximum values of all forces are higher for a standard drum than for a modified drum. The profile asymmetry substantially shortens the friction path of the horizontal link front torus on the seat bottom and relative total friction work on the seat bottom and lessens the occurrence probability of the slide of the horizontal link rear torus on the tooth flank. The modification of the profile causes also the asymmetric wear of link joints. The total relative friction work is considerably reduced in the front joint as compared to a conventional drum, and the total relative friction work in the rear joint is increasing at the same time.

ABRASIVE WEAR MECHANISMS OF ANTIWEAR COATINGS IN BALL-CRATERING TESTS

Tribologia ◽  
2016 ◽  
Vol 270 (6) ◽  
pp. 95-106
Author(s):  
Edyta OSUCH-SŁOMKA
Keyword(s):  
Abrasive Wear ◽  
Surface Coating ◽  
Boundary Surface ◽  
Work Conditions ◽  
Pvd Coatings ◽  
Repetitive Nature ◽  
Microscopic Techniques ◽  
Selection Of ◽  
Scanning Electron

The article is a continuation of research on the mechanisms of wear on PVD coatings observed after tests had been performed with the use of the ball-cratering method evaluating the wear. The work conditions of friction point in which tribological tests had been performed were calculated based on the optimization experiments described in independent studies [L. 1–2]. The aim of the article is to analyse the boundary surface coating–substrate resulting from abrasive wear. The observed area is located on the border of the trace of wear in the shape of a crater, at the point of the exit of the ball from the trace in accordance with the direction of the selection of the coating. The tested surface was observed with the use of microscopic techniques: scanning electron microscope (SEM) and interferometric microscope (WLI). The authors attempted to present the repetitive nature of the mechanism of the wear of thin PVD coatings with the use of the ball-cratering method, including its influences on receiving repeated traces of wear, which, in turn, has an influence on the determination of a reproducible value of the wear rate Kc, which is the factor determining the resistance of the tested coating to abrasive wear.

Geometric Calculations of the Chamfered Tip and the Protuberance Undercut of a Tooth Profile

2011 ◽  
Author(s):  
Milos Nemcek ◽  
Zdenek Dejl
Keyword(s):  
Mass Production ◽  
Gear Tooth ◽  
Tooth Profile ◽  
Measuring Device ◽  
Car Industry ◽  
Industry Standard ◽  
Tooth Flank ◽  
Computing Method ◽  
Circle Diameter

Nowadays special modified tools are mostly used for rough or semi-finishing milling in the mass production of ground or shaved gears today. These modifications ensure the desired chamfer at the head or the undercut at the bottom of the gear tooth. Diameters of the beginning and the end of the operational involute (exact knowledge of them is necessary for the calculation of important meshing parameters) are found by using several techniques. The first one is the simulation of the generating action of a hob tooth using suitable graphic software with the subsequent measuring of these diameters from the envelope of hob tooth positions which was created. The second one is measuring directly on the gear manufactured using a measuring device. These simulations or measuring are often not performed and the tool with recommended parameters of the protuberance or the ramp is simply chosen by an educated guess [1]. But it is not an acceptable technique in a mass production (car industry). Standard DIN 3960 [2] gives a certain manual for the determination of these diameters. It suggests the iterative method for the calculation of the chamfer beginning circle diameter but without a reliable guideline. And as regards the protuberance, it refers to the correct calculation only in theory. This paper deals with the computing method to determine diameters of the beginning and the end of the function part of a tooth flank involute. It is designed for a specified tool with modifications for creating the chamfer or the protuberance undercut. The paper also takes into account the necessary shaving (grinding) stock or the backlash. Furthermore it refers to possible problems when the basic profile of the generating tool with the protuberance is designed from the basic rack tooth profile.

Pitting Load Capacity of Helical Gears

2007 ◽  
Author(s):  
Bernd-Robert Ho¨hn ◽  
Peter Oster ◽  
Gregor Steinberger
Keyword(s):  
Calculation Method ◽  
Load Distribution ◽  
Load Capacity ◽  
Test Results ◽  
Calculation Methods ◽  
Helical Gears ◽  
Capacity Calculation ◽  
Overlap Ratio ◽  
Tooth Flank

In experimental analyzes the pitting load capacity of case carburized spur and helical gears is determined in back-to-back test rigs. The research program with one type of spur and 8 types of helical gears includes tests for the determination of influences of varying load distribution, overlap ratio and transmission ratio. The test results are presented and evaluated on the basis of the pitting load capacity calculation methods of ISO 6336-2/DIN 3990, part 2. A new DIN/ISO compatible calculation method for pitting load capacity is presented. This new calculation method comprehends helical gears more adequate than ISO 6336-2 / DIN 3990, part 2 and has the possibility to consider tooth flank modifications. The new calculation method is applied on test results and gears of a calculation study. It shows better accordance with the experimental test results than the present ISO 6336-2 / DIN 3990, part 2.

Determination of the influence of structural parameters of steels on their abrasive wear resistance

2021 ◽  
pp. 50-54
Author(s):  
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Computer Program ◽  
Abrasive Wear ◽  
Structural Parameters ◽  
Extreme Temperature ◽  
Abrasive Wear Resistance ◽  
Thermal Hardening ◽  
Heat Treated

Relationships are established between the parameters of the structure of heat-treated steels and their abrasive wear resistance. A computer program is developed for the choice of material and methods of thermal hardening in order to ensure the required wear resistance. Keywords: heat treatment, dislocation density, extreme temperature, lowalloy steel, computer program. [email protected]

Experimental Studies on Abrasive Wear of Surface-Hardened and Shot Peened Alloy Cast Steels

2016 ◽  
Vol 674 ◽  
pp. 201-206
Author(s):  
Andrzej Norbert Wieczorek
Keyword(s):  
Abrasive Wear ◽  
Cast Steel ◽  
Experimental Studies ◽  
Operating Conditions ◽  
Linear Wear ◽  
Plastic Properties ◽  
Cast Steels ◽  
Wear Tests ◽  
Alloy Cast

The paper presents the results of wear tests of shot-peened and non-shot-peened cast steels with the use of an especially designed test rig simulating real operating conditions of chain wheels. The chain wheels subjected to tests were operated with the use of loose quartz abrasive. The studies involved the determination of strength and plastic properties, hardness distributions, microstructure and linear wear of the selected cast steels. Based on the results obtained, the following was found: the abrasive wear of cast steel chain wheels increased after shot peening.

The Undercutting of Hobbed Spur Gear Teeth

1983 ◽  
Vol 105 (1) ◽  
pp. 122-128 ◽  
Author(s):  
R. G. Mitchiner ◽  
H. H. Mabie ◽  
H. Moosavi-Rad
Keyword(s):  
Spur Gear ◽  
Gear Teeth ◽  
Pressure Angle ◽  
Number Of Teeth ◽  
Minimum Number ◽  
Straight Portion ◽  
Base Circle ◽  
Tooth Flank ◽  
General Method

A general method is presented for the determination of the minimum number of teeth that can be cut in a spur gear without undercutting by a rounded-tooth tip hob. The minimum number of teeth to produce undercutting was investigated for three trochoid/tooth-profile relations: (1) trochoid tangent to the involute profile at the base circle, (2) trochoid tangent to a straight portion of the tooth flank, and (3) trochoid intersecting the involute profile at the base circle. It was found that in order to avoid undercutting, the minimum number of teeth cut into a gear occurs when the trochoid is tangent to the involute at the base circle. There is no set of hob parameters such that the trochoid intersects the involute profile at the base circle nor does the case of the trochoid being tangent to a straight flank exist. A set of figures representing the variation of the amount of undercutting versus the number of teeth, radius of hob-tooth tip, hob addendum, cutting pressure angle, and the corresponding derivatives are included for a typical gear.

THE INFLUENCE OF KINEMATIC CONDITIONS OF SLIDE/ROLL FRICTION ON THE WEAR OF PE-UHMW

Tribologia ◽  
2016 ◽  
Vol 265 (1) ◽  
pp. 35-43
Author(s):  
Piotr KOWALEWSKI ◽  
Filip WOŹNIAK
Keyword(s):  
Contact Point ◽  
Roll Motion ◽  
Linear Wear ◽  
Friction Couple ◽  
Kinematic Parameters ◽  
Steel Cylinder ◽  
Slip Ratio ◽  
Polymer Component ◽  
The Impact

The paper describes a study of steel 316L – polyethylene PE-UHMW friction couple during the slip-roll motion. The analysis is focused on the linear wear of polymer plates at various rolling-to-slip ratio values. Kinematic parameters of the friction nodes were angular velocity of the steel cylinder – ω, and the linear speed of the polymer plate – vp. In the experiment, the geometrical slip speeds were constant (s = 25 mm/s for each case). The constant geometrical slip speeds for different values of the plate speed (traverse of the contact point) vp allowed the determination of the influence of that parameter on the linear wear of the polymer component. The research showed the impact of plate speed (the contact point's traverse) vp on the values of the linear wear of the polyethylene, and the polymer's linear wear increase at the extreme ratios of the slip-roll motion (vp = 0, ω = 0).

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