Assessment of the load capacity of chemically-thermally hardened gears with local tooth contact

2020 ◽  
pp. 34-37
Author(s):  
V.I. Korotkin ◽  
E.M. Kolosova ◽  
N.P. Onishkov
Keyword(s):  
Stress State ◽  
Thermal Treatment ◽  
Load Capacity ◽  
Contact Spot ◽  
Contact Stresses ◽  
Gear Transmission ◽  
Tooth Contact ◽  
Strength Criteria ◽  
Local Contact ◽  
First Time

For the first time, the necessity of taking into account the stress state of the teeth in the peripheral parts of the contact spot when calculating chemically-thermally hardened gears with local contact of the teeth is substantiated. Keywords gear transmission, chemical-thermal treatment, local contact, contact spot, contact stresses, strength criteria. [email protected]

Assessing the Load Capacity of Hardened Gears with Local Tooth Contact

2020 ◽  
Vol 40 (11) ◽  
pp. 905-907
Author(s):  
V. I. Korotkin ◽  
E. M. Kolosova ◽  
N. P. Onishkov
Keyword(s):  
Load Capacity ◽  
Tooth Contact

scholarly journals Forensic Engineering Analysis Of Dynamic Wheel Tire Impact Ejection Of Manhole Covers

2007 ◽  
Vol 24 (2) ◽  
Author(s):  
Jon O. Jacobson ◽  
Kravitz Michael
Keyword(s):  
Focal Point ◽  
Contact Stresses ◽  
Engineering Analysis ◽  
Local Contact ◽  
Forensic Engineering ◽  
Tire Forces

This Paper Will Examine The Effect Of Vehicle Tires Driving Over A Street Hardware Manhole Cover That Was Not Properly Seated And Resulted In The Motion Of The Manhole Cover Which Eventually Either Became Unseated And Moved Along The Roadway Surface Or Failed And Fell Into The Manhole. As A Result Of The Open Uncovered Manhole, A Vehicle Tire Struck The Open Manhole Resulting In The Driver Losing Control Of The Vehicle And Crashing Into A Tree. Several Of The Passengers Were Injured And A Law Suit Ensued. The Issue Of Notice Was The Focal Point Of The Case. The Defendants Argument Was That It Had No Notice Of The Defect And The Plaintiffs Argument Was That The Defendant Had Actual And Constructive Notice Because The Defect Was Caused By The Roadway Resurfacing Project. Two Examples Will Be Presented Showing How A Manhole Cover Can Be Dislodged They Are: 1) The Dynamic Expulsion From Tire Forces On The Rocking Manhole Cover, And 2) The Fracture Of The Manhole Cover From Local Contact Stresses From A Misaligned Adjusting Riser Frame Installed During The Repaving.

Performance of a Short Multi-Grooved Capillary Compensated Hydrostatic Journal Bearing

1968 ◽  
Vol 183 (16) ◽  
pp. 107-115
Author(s):  
J. K. Patrick ◽  
N. N. S. Chen
Keyword(s):  
Journal Bearing ◽  
Load Capacity ◽  
Flow Characteristics ◽  
Lubricating Oil ◽  
Load Carrying Capacity ◽  
Straight Line ◽  
Load Carrying ◽  
Capillary Type ◽  
First Time ◽  
Oil Film Pressure

This paper presents the results of an extensive experimental investigation into the performance of a short multi-grooved bearing subjected to a range of static and alternating loads. Lubricating oil was supplied, at pressures of up to 2000 lb/in2, to capillary type restrictors connected to 10 closed-end axial grooves in the bearing. The bearing had a length/diameter ratio of 1/3 and operated with a journal speed and load frequency of 327 c/min. Measured load capacity, stiffness, and flow characteristics indicate that bearings of this type have a significant load-carrying capacity at zero journal speed and that the load capacity is increased by journal rotation. A feature of the journal behaviour under alternating loads is the movement of the journal centre along a straight line coincident with the load plane. The extensive oil film pressure surveys indicate for the first time the pressure distribution within narrow hydrostatic bearings and provide a basis for a realistic theoretical analysis of this type of bearing.

Meeting the Doctors

1997 ◽  
Vol 3 (5) ◽  
pp. 148-151
Author(s):  
Michael Bolger
Keyword(s):  
Health Authority ◽  
Medical Negligence ◽  
High Court ◽  
Senior Consultant ◽  
Face To Face ◽  
Local Contact ◽  
Hospital Doctors ◽  
The Impact ◽  
First Time

Michael Bolger is an AVMA Director and local contact. As a result of medical negligence, he is paraplegic and confined to a wheelchair for the rest of his life. He won substantial damages in the High Court after suing the Health Authority and senior consultant concerned. Michael has written several articles and has been interviewed on radio and television about his experience as a victim of medical negligence and as a plaintiff and has views on the need for change. In this article, Michael describes the seminar at which he was the lead speaker at the AVMA Medical Negligence Conference, held on 4–5th July 1997, where he discussed the impact of medical negligence on victims and doctors with a group of senior hospital doctors and consultants, the first time that a face-to-face discussion of this kind has taken place.

Effect of non-Newtonian magneto-elastohydrodynamic on performance characteristics of slider-bearings

2019 ◽  
Vol 71 (10) ◽  
pp. 1158-1165
Author(s):  
Mouhcine Mouda ◽  
Mohamed Nabhani ◽  
Mohamed El Khlifi
Keyword(s):  
Friction Coefficient ◽  
Design Methodology ◽  
Reynolds Equation ◽  
Load Capacity ◽  
Transverse Magnetic ◽  
Finite Width ◽  
Two Dimensional ◽  
Content Type ◽  
Slider Bearings ◽  
First Time

Purpose This study aims to examine the magneto-elastohydrodynamic effect on finite-width slider-bearings lubrication using a non-Newtonian lubricant. Design/methodology/approach Based on the magneto-hydrodynamic (MHD) theory and Stokes micro-continuum mechanics, the modified two-dimensional Reynolds equation including bearing deformation was derived. Findings It is found that the bearing deformation diminishes the load-capacity and increases the friction coefficient in comparison with the rigid case. However, the non-Newtonian effect increases load-capacity but decreases the friction coefficient. Moreover, the use of a transverse magnetic field increases both the friction coefficient and load capacity. Originality/value This study combines for the first time MHD and elastic deformation effects on finite-width slider-bearings using a non-Newtonian lubricant.

scholarly journals Contact stresses in point frogs

2020 ◽  
Vol 164 ◽  
pp. 03034
Author(s):  
Boris Glusberg ◽  
Vadim Korolev ◽  
Olga Lokteva ◽  
Irina Shishkina
Keyword(s):  
Stress State ◽  
Contact Stress ◽  
Contact Stresses

The methodology for calculating the contact stress state for various contact types of frogs and wheel is presented. The magnitudes of contact stresses in the frogs can be calculated according to the Hertz-Belyaev method, taking into account certain evaluating factors.

Multi-objective optimization of the manufacture of face-milled hypoid gears on numerical controlled machine tool

2020 ◽  
pp. 095440542097803
Author(s):  
Vilmos V Simon
Keyword(s):  
Machine Tool ◽  
Angular Displacement ◽  
Contact Stresses ◽  
Machining Process ◽  
New Method ◽  
Energy Losses ◽  
Hypoid Gear ◽  
Tooth Contact ◽  
Hypoid Gears ◽  
Gear Manufacture

A new method is presented for advanced manufacture of hypoid gears on numerical controlled machine tool. The tool geometry and machine tool settings are determined to introduce the optimal tooth modifications into the teeth of hypoid gears. The goal is to reduce the maximum tooth contact stresses, angular displacement error of the driven gear, and energy losses in the oil film existing between tooth surfaces. The calculation is based on the optimal variation of machine tool settings on the classical machine tool for hypoid gear manufacture. The novelty of the method is that during the machining process of teeth surfaces, the variation of machine tool settings on the cradle-type hypoid generator is conducted by polynomial functions of fifth-order. By an algorithm, this variation of machine tool settings is transferred to the numerical controlled machine tool for hypoid gear manufacture (hypoid generator). The obtained results have shown that by applying the optimal manufacture process, considerable reductions in tooth contact stresses and angular displacement errors of the driven gear, and a moderate reduction in energy losses were obtained. Therefore, by applying this new method in practice, advanced manufacture of hypoid gears on CNC hypoid generator is made possible, resulting improved operating characteristics of the hypoid gear pair.

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.

Stiffness Optimization of Hollow Cylindrical Rolling Element Bearing

2008 ◽  
Author(s):  
P. H. Darji ◽  
D. P. Vakharia
Keyword(s):  
Load Capacity ◽  
Contact Problems ◽  
Contact Stresses ◽  
Rolling Element Bearing ◽  
Thin Wall ◽  
Element Analysis ◽  
Normal Loading ◽  
Rolling Element ◽  
Rolling Elements ◽  
Minimum Stress

Since being originally introduced, cylindrical rolling element bearings have been significantly improved, in terms of their performance and working life. A major objective has been to decrease the Hertz contact stresses at the roller–raceway interfaces, because these are the most heavily stressed areas in a bearing. It has been shown that bearing life is inversely proportional to the stress raised to the ninth power (even higher). Investigators have proposed that under large normal loads a hollow element with a sufficiently thin wall thickness will deflect appreciably more than a solid element of the same size. An improvement in load distribution and thus load capacity may be realized, as well as contact stress is also reduced considerably by using a bearing with hollow rolling elements. Since for hollow rolling element no method is available for the calculation of contact stresses and deformation. The contact stresses in hollow members are often calculated by using the same equations and procedures as for solid specimens. This approach seems to be incorrect. Recently, the Finite Element Analysis (FEA) has been successfully used to evaluate contact problems for the roller bearings. Investigations have been made for hollow rollers in pure normal loading. Different hollowness percentages ranging from 0% to 90% have been analysed in FEA software to find the optimum percentage hollowness which gives minimum stress and finally longest fatigue life.

scholarly journals Analysis of influence of random distribution of assembly clearance on deflection and load capacity of folding beams

2018 ◽  
Vol 67 (1) ◽  
pp. 93-105
Author(s):  
Jan Marszałek ◽  
Mieczysław Piechota
Keyword(s):  
Random Distribution ◽  
Civil Engineering ◽  
Load Capacity ◽  
Random Occurrence ◽  
Measurement Results ◽  
First Time

The article includes the analysis of influence of random distribution of assembly clearance of various sizes on deflections and the load capacity of the folding beam based on fixed supports. This analysis includes seven variants of the random occurrence of individual pins in the interconnections between the two-span folded beam components. Measurement results for these variants were compared with the results obtained for the variant with fixed (medium) assembly clearance. Analyses of deflections and load capacity confirmed the correctness of acceptance of the fixed assembly clearance for the calculation of folding bridge. This issue was undertaken for the first time, which is the originality of this study. Keywords: civil engineering, folding bridges, assembly clearance

Sign in / Sign up

Export Citation Format

Share Document