Calculation of Cylindrical Worm Gear Drives of Different Tooth Profiles

1981 ◽  
Vol 103 (1) ◽  
pp. 73-82 ◽  
Author(s):  
H. Winter ◽  
H. Wilkesmann
Keyword(s):  
Coefficient Of Friction ◽  
Theoretical Basis ◽  
Power Loss ◽  
Influence Factor ◽  
Load Capacity ◽  
Worm Gear ◽  
Important Influence ◽  
Test Results ◽  
The Coefficient Of Friction ◽  
Gear Drives

The formulae of classical hydrodynamics are not suitable for the calculation of load capacity and power loss of worm gear drives. Thus a theoretical basis had to be developed for the comparison of different tooth profiles, materials of worm and worm wheel and lubricants. The data obtained were compared with test results. It proved that the coefficient of friction is an important influence factor.

Friction-Instability: A New Design Parameter for Brakes

1971 ◽  
Vol 93 (4) ◽  
pp. 1225-1228 ◽  
Author(s):  
W. L. Starkey ◽  
T. G. Foster ◽  
S. M. Marco
Keyword(s):  
Quality Control ◽  
Coefficient Of Friction ◽  
Design Parameter ◽  
Control Device ◽  
Experimental Facility ◽  
Test Results ◽  
Effective Manner ◽  
The Coefficient Of Friction ◽  
Brake Lining ◽  
The Right

A new design parameter, friction-instability, is defined in this paper. Friction-instability is a variation in the coefficient of friction which may occur at any time during the life of a brake lining. A friction-index is defined which measures this variation. A lining which has a high friction index may tend to cause an automobile to swerve either to the right or to the left. A unique experimental facility is described by means of which the friction-instability characteristics of brake linings can be measured. Test results using this facility are presented and interpreted. The friction-index is proposed as a new parameter which should be taken into consideration when brakes are designed and, developed. This index should be particularly useful as a quality control device to insure that machines which use mass-produced braking systems will perform in a safe and effective manner.

Simulating Torsional Slip in V-Band Clamp Joints

2015 ◽  
Vol 798 ◽  
pp. 53-58
Author(s):  
Salahaddin M. Sahboun ◽  
Simon M. Barrans
Keyword(s):  
Finite Element ◽  
Coefficient Of Friction ◽  
Load Capacity ◽  
Contact Region ◽  
Finite Element Technique ◽  
Torsional Load ◽  
V Band ◽  
The Coefficient Of Friction ◽  
Element Technique

In this paper a finite element technique to predict the torsional load capacity of V-band clamp joints is presented. The development of this complex, multi-step analysis is explained and the results compared with alternate theories which ignore or take account of transverse friction in the band to flange contact region. It is shown that accounting for transverse friction yields a better comparison with the finite element results for lower coefficients of friction whilst ignoring this component gives better results for higher coefficients of friction. Torsional load capacity is shown to increase with band diameter and T-bolt tension but to be less dependent on the coefficient of friction.

The Data Processing Technique of Metallic Sheet Friction Coefficient Determination

2012 ◽  
Vol 184-185 ◽  
pp. 688-691
Author(s):  
Huan Xue ◽  
Rong Feng Li ◽  
Hong Chuan Zhu
Keyword(s):  
Data Processing ◽  
Coefficient Of Friction ◽  
Normal Pressure ◽  
Processing Technique ◽  
Test Results ◽  
Friction Zone ◽  
Data Processing Method ◽  
The Coefficient Of Friction ◽  
Processing Techniques ◽  
Metallic Sheet

The definition and research background of friction is introduced. The reason of generation of friction is analyzed, the importance of the coefficient of friction test in sheet metal forming field is indicated. The testing principle of coefficient of friction on metallic sheet is presented. The basic data processing method of the test is described. Two important data processing techniques which will obviously effects the test results, including effective friction zone and normal pressure have been carefully studied. The comparison result shows these techniques can effectively enhance the testing stability and precision.

Finite element modelling and load share analysis for involute worm gears with localized tooth contact

2001 ◽  
Vol 215 (7) ◽  
pp. 805-816 ◽  
Author(s):  
F Yang ◽  
D Su ◽  
C. R. Gentle
Keyword(s):  
Finite Element ◽  
Load Capacity ◽  
Worm Gear ◽  
Tooth Contact Analysis ◽  
Fe Modelling ◽  
Tooth Contact ◽  
Transmission Errors ◽  
Meshing Stiffness ◽  
Worm Gears ◽  
Gear Drives

A new approach has been developed by the authors to estimate the load share of worm gear drives, and to calculate the instantaneous tooth meshing stiffness and loaded transmission errors. In the approach, the finite element (FE) modelling is based on the modified tooth geometry, which ensures that the worm gear teeth are in localized contact. The geometric modelling method for involute worm gears allows the tooth elastic deformation and tooth root stresses of worm gear drives under different load conditions to be investigated. On the basis of finite element analysis, the instantaneous meshing stiffness and loaded transmission errors are obtained and the load share is predicted. In comparison with existing methods, this approach applies loaded tooth contact analysis and provides more accurate load capacity rating of worm gear drives.

Hydrodynamic Lubrication of a Porous Slider

1973 ◽  
Vol 15 (3) ◽  
pp. 232-234 ◽  
Author(s):  
J. Prakash ◽  
S. K. Vij
Keyword(s):  
Drag Coefficient ◽  
Closed Form ◽  
Coefficient Of Friction ◽  
Hydrodynamic Lubrication ◽  
Load Capacity ◽  
Centre Of Pressure ◽  
Slider Bearing ◽  
Frictional Drag ◽  
Pressure Load ◽  
The Coefficient Of Friction

A plane porous slider bearing is analysed and closed form expressions for pressure, load, frictional drag, coefficient of friction and centre of pressure are obtained. The effect of porosity is to decrease the load capacity and friction. However, the coefficient of friction is increased.

Comparison of Dry-Film and Zinc-Phosphate Lubricant for Tube Cold Forming

2011 ◽  
Vol 295-297 ◽  
pp. 2362-2365
Author(s):  
Zhi Yan Cheng
Keyword(s):  
Coefficient Of Friction ◽  
Zinc Phosphate ◽  
Test Results ◽  
Tube Surface ◽  
Cold Forming ◽  
Breakdown Time ◽  
Significant Difference ◽  
Potential Applications ◽  
The Coefficient Of Friction ◽  
Dry Film

Dry-film and zinc-phosphate (Zn-P) lubricants were compared for potential applications of dry-film lubricant in tube cold forming processes through the twist compression test. Test results showed that the coefficient of friction (m) had no significant difference between Zn-P soap lube and dry-film lube. The lube coating breakdown time is different between Zn-P soap and dry-film lube. A preliminary industrial trial with dry-film coated tube through the cold drawn over a mandrel showed that the tube surface quality is good and comparable with the Zn-P coated tubes.

scholarly journals Worm Gear Drives with Improved Kinematic Accuracy

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7825
Author(s):  
Wojciech Kacalak ◽  
Maciej Majewski ◽  
Zbigniew Budniak ◽  
Jacek Ponomarenkow
Keyword(s):  
Load Capacity ◽  
Worm Gear ◽  
Central Section ◽  
Positioning Systems ◽  
Kinematic Accuracy ◽  
Gear Drive ◽  
Fold Reduction ◽  
Different Types ◽  
Gear Drives ◽  
High Degree

This paper presents the fundamentals of the design and applications of new worm gear drive solutions, which enable the minimisation of backlash and are characterised by higher kinematic accuracy. Different types of worm surfaces are briefly outlined. Technological problems concerning the principles of achieving a high degree of precision in machining are also described. Special attention is paid to the shaping of conical helical surfaces. Increasing the manufacturing precision of drive components allows one to achieve both lower backlash values and lower levels of its dispersion. However, this does not ensure that backlash can be eliminated, with its value being kept low during longer periods of operation. This is important in positioning systems and during recurrent operations. Various design solutions for drives in which it is possible to reduce backlash are presented. Results of experiments of a worm gear drive with a worm axially adaptive only locally, in its central section, are presented. In this solution, it is possible to reduce backlash by introducing adjustment settings without disassembling the drive. An important scientific problem concerned defining the principles of achieving a compromise between the effectiveness of reducing backlash and the required load capacity of the drive. In this paper it has been shown that in worm gear drives with a locally axially adaptive worm, as well as with a worm wheel with a deformable rim, it is possible to achieve significant reduction of backlash. In high precision drives—for example, those with an average backlash value of <15 micrometers—this can enable more than a two-fold reduction of the average backlash value and more than a three-fold decrease of the standard deviation of local backlash values.

Operation of the induction motor in non-sinusoidal voltage supply conditions

2020 ◽  
Vol 8 (1) ◽  
pp. 13-20
Author(s):  
Tomasz Drabek ◽  
Krzysztof Krzyściak
Keyword(s):  
Induction Motor ◽  
Theoretical Basis ◽  
Induction Motors ◽  
Load Capacity ◽  
Mathematical Expression ◽  
Test Results ◽  
Sinusoidal Voltage ◽  
Torque Load ◽  
American Standard ◽  
Measurement Verification

The paper presents the theoretical basis of the mathematical expression derived from the American standard, used to determine the thermally permissible torque load capacity of the cage induction motors when supplied with distorted voltages. The results of the measurement verification of this expression for different voltage shapes supplying the tested motor are presented. The test results confirmed the correctness of the expression when the motor is supplied with distorted voltage with a limited number of higher harmonics.

TRIBOLOGICAL CHARACTERISTICS OF POLYURETHANES USED FOR THE SOLES OF FOOTWEAR

Tribologia ◽  
2021 ◽  
Vol 294 (6) ◽  
pp. 71-75
Author(s):  
Jacek Przepiórka ◽  
Marian Szczerek ◽  
Marian W. Sułek
Keyword(s):  
Coefficient Of Friction ◽  
Friction And Wear ◽  
Base Material ◽  
Operating Conditions ◽  
Test Results ◽  
Footwear Industry ◽  
Wear And Tear ◽  
Variable Friction ◽  
The Coefficient Of Friction ◽  
Shoe Soles

The inability to take into account the type of base material (floor, pavement, soil), as well as the inability to take into account the variable friction conditions – load, intermediary medium (water, loose abrasive, sand or other soil particles), sliding velocity, and ambient temperature – is a significant limitation the use of friction methods and devices used so far in the footwear industry to precisely anticipate the behavior of the bottom materials in the actual operating conditions of the footwear. These limitations prompted the authors to adapt a tribological tester for this purpose, used in the area of construction and operation of machines and material engineering. A research methodology was developed and, in order to verify it, measurements of the coefficient of friction and wear of polyurethane used for shoe soles in combination with a raw and varnished wooden substrate were carried out. The obtained test results are characterized by diversity, which proves the high research resolution of the developed method. It allows determining the coefficient of friction of associations influencing the slip of the footwear and the wear and tear that determines the length of use of the footwear.

Analysis of Porous Layered Journal Bearing Lubricated with Ferrofluid

2016 ◽  
Vol 819 ◽  
pp. 474-478 ◽  
Author(s):  
T.V.V.L.N. Rao ◽  
A.M.A. Rani ◽  
T. Nagarajan ◽  
F.M. Hashim
Keyword(s):  
Magnetic Field ◽  
Layer Thickness ◽  
Coefficient Of Friction ◽  
Journal Bearing ◽  
Load Capacity ◽  
Lubricant Layer ◽  
Distance Ratio ◽  
Load Carrying ◽  
Magnetic Field Model ◽  
The Coefficient Of Friction

This paper presents an analysis of porous layered long journal bearing lubricated with ferrofluid using displaced infinitely long wire magnetic field model. The ferrofluid flow in the porous region is analyzed using modified Brinkman model. Nondimensional pressure and shear stress expressions are derived using Reynolds boundary conditions. Nondimensional load capacity and coefficient of friction are evaluated under the influence of permeability of porous media, porous layer thickness, lubricant layer thickness, magnetic field intensity and distance ratio parameter. A porous layered journal bearing lubricated with ferrofluid increases the load carrying capacity and reduces the coefficient of friction.

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