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When a vehicle is cruising, unpleasant noise in the 4 to 5 KHz high-frequency band can be heard at the center of all seats in the vehicle cabin. In order to specify the source of this noise, the correlation between the noise and airborne noise from the outer surface of the transmission was determined, and transfer path analysis was conducted for the interior of the transmission. The results indicated that the source of the noise was the 0th-order breathing mode specific to the drive motor. To make it possible to predict this at the desk, a vibrational analysis method was proposed for drive motors made up of laminated electrical steel sheets and segment-type coils. Material properties data for the electrical steel sheets and coils was employed in the drive motor vibrational analysis model without change. The shapes of the laminated electrical steel sheets and coils were also accurately modeled.

Infinitely variable transmission (IVT) is one of the methods used to extend the ratio coverage. In this paper, a dynamic behavior analysis technology was developed for an IVT utilizing a half-toroidal variator as the shifting device. The traction coefficient of traction fluid used for the half-toroidal IVT varies greatly according to contact surface slip rate, contact pressure and fluid temperature. This paper used measurement values from a four-roller machine to identify the coefficient, and then applied it to the dynamic behavior analysis. Use of the identified traction coefficient enabled power transmission characteristic predictions of a half-toroidal variator. To reproduce the elastic deformation in actual operation, the research used the Finite Element Method (FEM) for modeling. This model was also used to visualize the frictional state of traction surfaces during operation.

The mechanism of vibration in a metal pushing V-belt was analyzed using a simulation of the dynamic behavior of the belt in order to identify measures in response to unexpected noise occurring during CVT development. The results showed that the unexpected noise originated in self-induced vibration occurring when the elements of the belt moved in the radial direction close to the exit of the drive pulley. This paper will also discuss the realization of a method of reducing the unexpected noise.

In designing CVT pulleys, the effect of the fit clearance of the movable pulleys and their stiffness on the transmission efficiency and strength of the metal pushing V-belt is not necessarily clear. The research discussed in this paper introduced a pulley model that defined the pulleys as elastic bodies to a previously developed technology for the prediction of the transmission efficiency of the belts. As a result, it was found that when the fit clearance is reduced, the transmission efficiency of the belt is increased, and the amplitude of stress on the innermost rings and the element neck section is reduced. In addition, it was found that if pulley stiffness was reduced transmission efficiency was also reduced, and the amplitude of stress on the element neck section increased. This indicated that the fit clearance and the pulley stiffness changed the degree of deflection of the pulleys in the axial direction.