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Many analyses of gear rattle caused by drive line resonance have been reported. The fewer number of cases can be observed with analysis of drive-rattle in comparison with that of gear train idling-rattle. This paper introduces the method of evaluating drive-rattle objectively. And this paper introduces the method of specifying gears, which have the large contribution rate to drive-rattle, at a single measurement attempt with a vehicle. This method analyzes the relationship between gear vibration and transmission case vibration. In addition, nonlinear drive-rattle simulation has been developed with consideration given to gear backlash. Therefore, more systematic drive-rattle analysis has become possible.

This paper describes Computer Aided Expert System for Designing transmission. Design knowledge is classified into 2 groups - “CLASS FRAME” showing the concept relative with subject of study and “INSTANCE FRAME” displaying some examples together with knowledges in the form of diagram defined on frame as image data. These data were hierarchically sorted out for problem reduction and very effective and easy to understand knowledge representation was achieved. Besides that, experimental knowledge was processed by either probability theory based on parameter of certainty factor determining the quantity of specified information by using predicate logic or fuzzy inference using membership function both of which, in turn, made it possible to obtain reasonable and still yet optimum answer. Expert tool of personal computer can be employed for this system, and external program such as gear specification calculation program or gear stress calculation program can be executed by any user.

This study has revealed by taking nondimensional measures that the vibrational characteristics, basically the behaviour of stiffness, of helical gear pairs whose transverse and overlap contact ratios are invariant are identical. The feature is colligated correspondingly at the point on the contact ratio domain by the coordinate of their transverse and overlap contact ratio. By the colligation, the charts have been proposed as named the performance diagram on vibration, which indicate the level of vibration of a pair by contour lines on the contact ratio domain, after the vibrations of helical gear pairs are calculated by a developed simulator. The work has established the method of easy design and improvement for the lower vibration helical gear pair by a cursory glance at these proposed diagrams.

Many problems have been encountered in attempting to clarify the behaviors of drivetrain components from the standpoint of the power loss. This paper describes the analytical and experimental research to develop a method of measuring the total power losses of transmission and axle whereby far more accurate test results can be obtained than by the conventional means with good repeatability. In this pursuit, the power loss of the drivetrain is divided into two groups, i.e. gear tooth friction loss and lubricant churning loss, with the resulting practical formulation which permits calculation of these two losses on a separate basis. Also covered are the results so far achieved by means of practical application of the above approach and concept in both bench and field testings aiming at improvement of fuel economy and prediction of the drivetrain lubricant temperatures in the field operation.

CORRELATION OF BENDING STRENGTH AND ERRORS OF HELICAL GEAR has not been clarified sufficiently even now. As the investigation by using only experimental method is not sufficient and so the analytical method of obtaining gear bending strength has been developed by one of the authors. Hence, the correlation of bending strength and errors, especially in the aspect of the direction of pressure angle error and tooth trace error, is clarified by this analytical method which was verified by some experiments. And by further investigations, it is confirmed that the helical gear is tougher against the negative pressure angle error, and the fine module gear is sensitive against the errors.