Problems in the Design and Development of an Economical Automobile Gear-box

1953 ◽  
Vol 7 (1) ◽  
pp. 11-27 ◽  
Author(s):  
T. C. Stott
Keyword(s):  
High Performance ◽  
Small Diameter ◽  
Gear Train ◽  
Vehicle Performance ◽  
Helical Gears ◽  
Close Study ◽  
Gear Trains ◽  
Satisfactory Life ◽  
Useful Life ◽  
Compact Design

The demand for still greater reductions in weight together with the general stepping-up of vehicle performance with larger power units has placed upon the transmission engineer the onus of producing a small, lightweight and compact design yet capable of giving a satisfactory life. Economy in both weight and cost has become a primary requirement, and if this is to be met, a close study must be made of all the detailed components in order that the utmost can be obtained from each pound of material used. The maximum possible life of spur and helical gears is seldom achieved, as premature tooth failure occurs through poor face comformity of the mating teeth. The causes and effects of such nonconformities, whether dimensional or resulting after heat treatment, are dealt with, and the measures that can be adopted for their correction discussed. The elimination of any tendency to corner loading and, to a finer degree, the crown shaving of the teeth enable higher basic stresses to be adopted with corresponding smaller and more economical gear trains. Investigations into syncromesh mechanisms have indicated that synchronizing efficiency depends largely on attention to certain small details. An appreciation of these points will permit of quite small diameter synchronizers functioning satisfactorily without their useful life being in any way impaired by the higher loadings involved. Syncromesh problems are treated generally with particular detailed reference to design for high performance. It is unfortunate but nevertheless axiomatic that the tendency to self-disengagement of the gears increases as the loadings and stresses of the components are increased, and no paper on the design of an efficient economical transmission could be complete without its mention. The general causes of self-disengagement are discussed together with design features which can be embodied for its avoidance. The problems generally associated with the gear train which present definite requirements, of the casing, shafts, selector mechanism, etc., are dealt with. In conclusion, descriptions of the test equipment and tests used in the development of high-duty transmissions are given. The MS. of this paper was received at the Institution on 5th February 1953. For the Report of the meeting in London, at which this paper was presented, see p. 27.

IMPROVEMENT OF METHODICAL SUPPORT IN OPERATION SETUP OF UNIVERSAL MACHINE-TOOLS AT MOTOR CAR REPAIR COMPANIES

2021 ◽  
Vol 2021 (6) ◽  
pp. 36-46
Author(s):  
Andrey Fot ◽  
Vladimir Rassoha ◽  
Evgeniy Pen'kov
Keyword(s):  
Comparative Analysis ◽  
Machine Tools ◽  
Numerical Experiments ◽  
High Performance ◽  
Operation Time ◽  
Gear Train ◽  
Labor Intensity ◽  
Universal Machine ◽  
Gear Trains ◽  
Definition Of

The investigation purpose: simplification and ensuring tooling high performance of two-pair gear trains in machines with change gears. Methods used: numerical experiments for the characteristics definition of change gear sets in gear trains, a comparative analysis of different sets characteristics, a result visualization in a table form. Relevance of the method offered is substantiated with considerable labor intensity in the definition of the gear combination in gear trains by existing methods based on tables use mainly through possible way selection. Novelty: there are offered special algorithms of setup calculations decreasing operation time for the choice of gear combinations of gear trains. Basic results: there are developed computer programs for the definition of gear train combinations required and an electronic directory for machine-tool two-pair gear train setups recommended for use by workers of technological departments and in design service in production activities of engineering and motor car repair companies, in research centers and colleges (in thesis investigations, in training processes of engineering experts).

Prospects for convergent beam electron diffraction with a 200kV cold field-emission transmission electron microscope

1991 ◽  
Vol 49 ◽  
pp. 466-467
Author(s):  
J W Steeds ◽  
R Vincent
Keyword(s):  
Field Emission ◽  
High Performance ◽  
Small Diameter ◽  
Convergent Beam Electron Diffraction ◽  
Zone Axis ◽  
Medium Voltage ◽  
Transmission Electron ◽  
Good Crystallinity ◽  
Special Modification ◽  
Convergent Beam

We review the analytical powers which will become more widely available as medium voltage (200-300kV) TEMs with facilities for CBED on a nanometre scale come onto the market. Of course, high performance cold field emission STEMs have now been in operation for about twenty years, but it is only in relatively few laboratories that special modification has permitted the performance of CBED experiments. Most notable amongst these pioneering projects is the work in Arizona by Cowley and Spence and, more recently, that in Cambridge by Rodenburg and McMullan.There are a large number of potential advantages of a high intensity, small diameter, focussed probe. We discuss first the advantages for probes larger than the projected unit cell of the crystal under investigation. In this situation we are able to perform CBED on local regions of good crystallinity. Zone axis patterns often contain information which is very sensitive to thickness changes as small as 5nm. In conventional CBED, with a lOnm source, it is very likely that the information will be degraded by thickness averaging within the illuminated area.

A New Technique Based on Loops to Investigate Displacement Isomorphism in Planetary Gear Trains

2002 ◽  
Vol 124 (4) ◽  
pp. 662-675 ◽  
Author(s):  
V. V. N. R. Prasad Raju Pathapati ◽  
A. C. Rao
Keyword(s):  
Graph Isomorphism ◽  
Planetary Gear ◽  
Degree Of Freedom ◽  
Gear Train ◽  
Graph Representation ◽  
Kinematic Structure ◽  
Graph Representations ◽  
Planetary Gear Trains ◽  
Gear Trains ◽  
A New Technique

The most important step in the structural synthesis of planetary gear trains (PGTs) requires the identification of isomorphism (rotational as well as displacement) between the graphs which represent the kinematic structure of planetary gear train. Previously used methods for identifying graph isomorphism yielded incorrect results. Literature review in this area shows there is inconsistency in results from six link, one degree-of-freedom onwards. The purpose of this paper is to present an efficient methodology through the use of Loop concept and Hamming number concept to detect displacement and rotational isomorphism in PGTs in an unambiguous way. New invariants for rotational graphs and displacement graphs called geared chain hamming strings and geared chain loop hamming strings are developed respectively to identify rotational and displacement isomorphism. This paper also presents a procedure to redraw conventional graph representation that not only clarifies the kinematic structure of a PGT but also averts the problem of pseudo isomorphism. Finally a thorough analysis of existing methods is carried out using the proposed technique and the results in the category of six links one degree-of-freedom are established and an Atlas comprises of graph representations in conventional form as well as in new form is presented.

A Lightweight Split-Torque Transmission for a 330 KW Helicopter

1982 ◽  
Vol 196 (1) ◽  
pp. 11-22 ◽  
Author(s):  
G White
Keyword(s):  
Gear Train ◽  
Main Rotor ◽  
Speed Reduction ◽  
Torque Transmission ◽  
Current Production ◽  
Gear Trains ◽  
Fixed Axis ◽  
Three Stages ◽  
A Current ◽  
Split Torque

A simple split-torque gear train is used as the main rotor transmission of a single-engine helicopter. Overall speed reduction ratio achieved is 103:1 between the engine at a nominal 36 000 rev/min and the main rotor at 350 rev/min. This ratio is generated from three stages of fixed-axis gear trains containing only eight gears. Alternative configurations are outlined and discussed. Comparison with a current production design shows the split torque arrangement offers reductions in weight, height, and drive train losses. A low total of gears and bearings offers the potential for improved reliability.

Topological Synthesis of Epicyclic Gear Trains Using Vertex Incidence Polynomial

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Vinjamuri Venkata Kamesh ◽  
Kuchibhotla Mallikarjuna Rao ◽  
Annambhotla Balaji Srinivasa Rao
Keyword(s):  
High Velocity ◽  
Mechanical Energy ◽  
Gear Train ◽  
Recursive Method ◽  
Gear Pair ◽  
Simple Method ◽  
Epicyclic Gear ◽  
Thick Line ◽  
Gear Trains ◽  
Isomorphic Graphs

Epicyclic gear trains (EGTs) are used in the mechanical energy transmission systems where high velocity ratios are needed in a compact space. It is necessary to eliminate duplicate structures in the initial stages of enumeration. In this paper, a novel and simple method is proposed using a parameter, Vertex Incidence Polynomial (VIP), to synthesize epicyclic gear trains up to six links eliminating all isomorphic gear trains. Each epicyclic gear train is represented as a graph by denoting gear pair with thick line and transfer pair with thin line. All the permissible graphs of epicyclic gear trains from the fundamental principles are generated by the recursive method. Isomorphic graphs are identified by calculating VIP. Another parameter “Rotation Index” (RI) is proposed to detect rotational isomorphism. It is found that there are six nonisomorphic rotation graphs for five-link one degree-of-freedom (1-DOF) and 26 graphs for six-link 1-DOF EGTs from which all the nonisomorphic displacement graphs can be derived by adding the transfer vertices for each combination. The proposed method proved to be successful in clustering all the isomorphic structures into a group, which in turn checked for rotational isomorphism. This method is very easy to understand and allows performing isomorphism test in epicyclic gear trains.

Meshing Efficiency Analysis of Two Degree-of-Freedom Epicyclic Gear Trains

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Essam Lauibi Esmail
Keyword(s):  
Reference Frame ◽  
Power Efficiency ◽  
Power Flow ◽  
Flow Direction ◽  
Efficiency Analysis ◽  
Degree Of Freedom ◽  
Gear Train ◽  
Epicyclic Gear ◽  
Gear Trains ◽  
Two Degree Of Freedom

The concept of potential power efficiency is introduced as the efficiency of an epicyclic gear train (EGT) measured in any moving reference frame. The conventional efficiency can be computed in a carrier-moving reference frame in which the gear carrier appears relatively fixed. In principle, by attaching the reference frame to an appropriate link, torques can be calculated with respect to each input, output, or (relatively) fixed link in the EGT. Once the power flow direction is obtained from the potential power ratio, the torque ratios are obtained from the potential power efficiencies, the particular expression of the efficiency of the EGT is found in a simple manner. A systematic methodology for the efficiency analysis of one and two degree-of-freedom (DOF) EGTs is described, and 14 ready-to-use efficiency formulas are derived for 2DOF gear pair entities (GPEs). This paper includes also a discussion on the redundancy of the efficiency formulas used for 1DOF GPEs. An incomplete in the efficiency formulas in previous literature, which make them susceptible to wrong application, is brought to light.

Enantiometric purity determination to 1 % level using a laser-based polarimetric HPLC detector

1990 ◽  
Vol 333 (1628) ◽  
pp. 166-168
Keyword(s):  
High Performance ◽  
Flicker Noise ◽  
Specific Rotation ◽  
Significant Advance ◽  
Chromatographic Peak ◽  
Chiral Molecule ◽  
Chiral Molecules ◽  
Noise Levels ◽  
Hplc Detector ◽  
Compact Design

The development of laser-based polarimetric detectors for high-performance liquid chromatography (HPLC) (Yeung et al . 1980; Bobbitt & Yeung 1986) with noise levels in the range of 0.1-10 p° has provided a significant advance in the quantitation of chiral molecules. We have designed an instrument based on an 820 nm diode laser which has the advantages of low source flicker noise and compact design (Lloyd et al . 1989). Detection limits were found to be in the range 0.1-2 pg, dependent on the specific rotation of the chiral molecule and the chromatographic peak width (Goodall et al. 1990).

Signal Flow Graphs for Spatial Gear Trains

1994 ◽  
Vol 116 (1) ◽  
pp. 326-331 ◽  
Author(s):  
R. Ma ◽  
K. C. Gupta
Keyword(s):  
Operations Research ◽  
Equations Of Motion ◽  
Planetary Gear ◽  
Gear Train ◽  
Signal Flow ◽  
Signal Flow Graphs ◽  
Planetary Gear Trains ◽  
Gear Trains ◽  
System Variables ◽  
Flow Graphs

Signal flow graphs (SFG) have been applied in many areas such as circuit analysis, controls, mechanical vibrations, statistics, and operations research. They have also been applied to the analysis of planetary gear trains which are planar, i.e., where all of the gear axes are parallel. In this paper, signal flow graphs are applied to spatial planetary gear trains. Some additional terminology and rules which are needed for this important application are developed in this paper and illustrated by examples. The significance of applying SFG to a gear system is that the graph describes the interrelationship among the system variables by linking causes and effects, offers the information about the topology of system connection, and the kinematic equations of motion can be written easily by inspection. In this way, it helps use to visualize and understand spatial gear train systems better.

Conceptual Design of Gear Differentials for Automotive Vehicles

1994 ◽  
Vol 116 (2) ◽  
pp. 565-570 ◽  
Author(s):  
Hong-Sen Yan ◽  
Long-Chang Hsieh
Keyword(s):  
Conceptual Design ◽  
Degrees Of Freedom ◽  
Planetary Gear ◽  
Gear Train ◽  
Design Constraints ◽  
Two Degrees Of Freedom ◽  
Design Concepts ◽  
Planetary Gear Trains ◽  
Gear Trains ◽  
Gear Differential

An automotive gear differential is a joint-fractionated planetary gear train with two degrees-of-freedom. We summarize the characteristics of planetary gear trains and the design constraints of noncoupled automotive gear differentials to synthesize their corresponding kinematic graphs. Based on these graphs and the proposed respecializing process, we generate the atlas of design concepts for automotive gear differentials with any types of gear pairs. As a result, there are 4, 25, and 156 design concepts for five-, six-, and seven-bar automotive gear differentials, respectively.

Sign in / Sign up

Export Citation Format

Share Document