By using the number of small gear teeth, normal module and first two-stage transmission ratio in every grade of cylindrical gear reducer as design variables, the minimum of overall gear central distances in reducer as objective function is derermined, and an optimization design mathematical model of three-stage cylindrical gear reducer is devoloped. The results of the optimization are more satisfying than normal design.

Using the number of pinion teeth,normal module and the first two-stage transmission ratio in the cylindrical gear reducer as design variables,Using the minimum of every stage central distances in reducer as objective function,an optimization design mathematical model of three-stage cylindrical gear reducer is established and an available optimization software is developed.

During the process of exchanging the coordinate dimensions to a series of holes,It′s necessary to set the safe area for composition tolerance zone to the hole′s central distances and expand the area according to different boundary conditions. At last,devived the calculation formula of coordinate dimensions tolerance.

RecentlyOmote showed that the Coda waves contain three periodsT1,T2,T3 of whichT1 increases with epi-central distances as observed by previous observers.

The diameter of the prisms and their mutual central distances were far greater than in the enamel of any known representative of present mammals.

The predictive calculations of the distribution of temperature and of heat flux in a reheating furnace may represent the roost important prediction of industrial furnaces.It is helpful not only to simplify the automatic control of furnaces but also to enhance the efficiency of thermotechnical automation.Main predictive calculation for this purpose performed nowadays is based on the zone method by H.C.Hotte[1],Since this method has only a restricted application in that the elementary gsseous zones (or surface...

The predictive calculations of the distribution of temperature and of heat flux in a reheating furnace may represent the roost important prediction of industrial furnaces.It is helpful not only to simplify the automatic control of furnaces but also to enhance the efficiency of thermotechnical automation.Main predictive calculation for this purpose performed nowadays is based on the zone method by H.C.Hotte[1],Since this method has only a restricted application in that the elementary gsseous zones (or surface zones) must be divided into the form of cubes (or into squares),it is necessary to introduce a new method for calculating the one-way direct exchange area by which the prediction for industrial furnaces can be used more widely and conveniently.With the replacement of cubic (or square) zones by rectangular zones,the induced formulae for calculating one-way direct exchange areas under eight different conditions are derived.Two types of induced formulae,which may be considered as the representatives of those under eight different conditions,are offered in this paper.In one case the direct exchange area lies between two parallel planes,and in other the exchange area lies between two gaseous zones.The induced formulae derived,determining the allowed values of exchange areas and providing for the equations of heat equilibrium,are applicable to the mathematical models of computers.The results computed are relatively precise.A group of equations of heat equilibrium in which all the divided zones in a furnace are involved may be solved simultaneously by a computer.Therefore,the space distribution of the temperature of gas and surface and that of the heat flux can be determined.Finally,the accuracy of results calculated by a computer is discussed and a ratio of length to width of divided zones of not more than 1.2 is proposed.NOMENCLATUREs——surface zone;g——gaseous zone;i,j——signs of segments divided from a zone;"__"——top line up the sign shows the direct exchange area;Q——radiation ability of one-way heat transfer (kcal/h);E——radiation intensity (kcal/m2·h);T——absolute temperature (K);V——volume (m3);K——gas absorbance (1/m);m,n——positive integers;r——central distance between two zones or two elements;x,y,z——cartisian coordinates (m);θ——plane angle (rad.);ψ——space angle (rad.);A,B,C——signs of divided zones (in addition,B is also the marginaldimension of zone); a,b,c,d,e and f——dimensions (m);":="——assigned symbol;xi——calculated value of direct exchange area between two zones;(xi)N——theoretical value of xi;ηΔ——relative error

A study on the effects of several factors, such as seismic magnitudes, epi-, central distances and local soil conditions on the configuration of, the ground acceleration response spectra (magnification curve) is presented. The results show that the magnitudes and the soil conditions would gite more significant effects on the response spectra than the epicentral distances;do. In addition, a series of improved designed spectra are recommended to be used in the earthquake resistant design.

In this paper, the central distance thinkness and backlash of the gear pair are regarded as a plane dimension Chain,and then the check formula of the gear-pair backlash is derived.lt supplemented the calculation of the value of K given by JB179-81-the accuracy system of involute cylindrical gear. The value of K is the backlash reduction produced due to the errors in machining and assembling of the gear pair.