Analytical and experimental study of bearing stresses developed on machine elements in contact (original) (raw)
Related papers
Strain, 2011
In this paper, a comprehensive methodology for calculating load sharing in multiple tooth contact is presented based on the experimental stress-optical method of caustics. The technique is applied to a set of poly-methyl-methacrylate gears at various meshing positions covering a complete meshing cycle, including single and multiple gear tooth contact. The load sharing factor (LSF) is calculated using well-established mathematical formulae from the photographs of the transmitted caustics and the obtained results are compared with the pertinent International Organisation for Standardisation and American Gear Manufacturers Association standards with which good agreement is verified. The proposed method is a reliable alternative for measuring load distribution in gear teeth compared with photoelasticity and other experimental techniques.
IOP Conference Series: Materials Science and Engineering, 2019
The article focuses on the development of methods for determining the allowable stresses to check the contact strength of the spur and helical gears under overload. Short-term overloads in gears occur under the action of maximum moments during the start-up of the device or due to the other reasons. The calculation of these loads is performed to check the static strength of the transmission teeth. The analysis of the limiting state of the material in the working area of the gear teeth was performed using the Pisarenko-Lebedev strength criterion, which is one of the most common strength conditions. The method of calculation of allowable stresses was developed. The calculation of limit stresses for normalized, improved or hardened wheels, as well as for the wheels after hardening by chemical-thermal treatment. The calculation results were compared with the values recommended by the standard. It was shown that the permissible contact stress for helical gears is slightly higher than for straight gears. Practically for all heat-treated steels used in the manufacture of gears, the norm of permissible limit stresses recommended by the standard is higher (in some cases significantly) compared to the stresses required from the conditions of contact strength.
Experimental study of load sharing in roller-bearing contact by caustics and photoelasticity
Problem statement: In this study a comprehensive methodology for calculating load sharing in Roller-bearing contact was presented based on the experimental stress-optical method of caustics and Photoelasticity. Approach: The theoretical equations describing the geometry of transmitted caustic in relation to the length of the contact zone were derived and a simple mathematical set of equations correlating the maximum diameter of transmitted caustic with the magnitude of load was given.For this contact problem, the basic theory of photoelasticity was given. Results: The techniques of caustics and photoelasticity were applied on a set of PMMA (Plexiglas) Roller-bearings and on a set of PCBA (Lexan) Roller-bearings, respectively. Conclusion: The proposed method of the caustics is a reliable alternative for measuring load distribution in Roller-bearings compared to photoelasticity technique.
Contact Stress On The Surface Of Gear Teeth With Different Profile
2010
Contact stress is an important problem in industry. This is a problem that in the first attention may be don-t appears, but disregard of these stresses cause a lot of damages in machines. These stresses occur at locations such as gear teeth, bearings, cams and between a locomotive wheel and the railroad rail. These stresses cause failure by excessive elastic deformation, yielding and fracture. In this paper we intend show the effective parameters in contact stress and ponder effect of curvature. In this paper we study contact stresses on the surface of gear teeth and compare these stresses for four popular profiles of gear teeth (involute, cycloid, epicycloids, and hypocycloid). We study this problem with mathematical and finite element methods and compare these two methods on different profile surfaces.
Analysis of Contact Stresses at Thohoidal Gearing by Numeric Approach
In this paper the analysis of contact stresses at trochoidal gearing of the rotational elements with fixed shaft axes and driving rotor that is connected with internal element is presented. At first, the basic characteristics and acting mechanisms of those pumps are presented in the paper. Also, the review of development and state of the art in the area of numerical analysis of gerotor pumps are presented. In the aim to determine the maximal stresses, in the second part of the paper, numerical analysis of contact stresses that are consequence of torque transmission from driving internal element to driven external gear is described. Graphical presentation of contact stresses values determined by numerical and analytical approach that is done, is presented in this part of the paper, in order to evaluate the differences and deviations of those values.
2014
Article deals with influence of mutual slewing of roller bearing rings on the principal stresses and their distribution at the contact area. Profile of rolling element is logarithmic. Roller bearing has been loaded by maximum specified load only in radial direction according to the ISO/TS 16281. In practice, the real roller bearings are not loaded only in the radial direction. Therefore, the angle has been gradually slewed from = 0' to 8' and equivalent principal stresses have been evaluated. This change influenced on contact conditions and contact stress distribution has changed.
CONTACT STRESSES ANALYSIS & MATERIAL OPTIMIZATION OF BALL BEARING USING HERTZ CONTACT THEORY
Rolling element bearings are mostly used in rotating machineries and consider as a most critical component. Proper functioning of bearings is most important in nuclear power stations, chemical plants, aviation industries and also process industries. In many rotating machinery Ball bearings are generally used, such as electric motors, material handling systems, turbines, generators, fan, pumps and compressors, etc. is essential equipment in engineering plants. A large survey on faults in the electric motor was carried out by Electric Power Research Institute (EPRI) in 1985and found that 41% of faults related to worn motor bearings. Well performance and reliability of rolling element bearings is essential for proper functioning of machines and to prevent failure of the machinery. Bearing health and performance can be easily identified by using health monitoring techniques.
Some Results from Simulating of Contact Stresses in the Case of Meshing of Gear Wheel and Gear Rack
tu-plovdiv.bg
Technique of modeling in the environment of CAD software SolidWorks'2005 about gears with different number of teeth z, module of teeth m, pressure angle α , profile shift coefficient k, about gear rack and about its assembly are presented in detail. Then threedimensional CAD models of the assembly are subjected by means of simulation loading to reaching allowable limit contact stresses. The investigation's results derived by means of finite elements calculation method about the influence profile shift coefficient x, number of teeth z, fillet R of gears wheel’s tooth on its limit capacity of loading are presented. These results and the results obtained by means of Hertzian contact theory are compared. An analysis about its capacity of loading is made and some conclusions are formulated.