Analysis of Transmission Efficiency and Transient Dynamics in Rubber V-belt Continuously Variable Transmission

Ryota Yamori･Tatsuhito Aihara (Hosei University)･Yutaka Kimoto (Exedy)

For the purpose of predicting the transmission efficiency during operation of a rubber belt-type CVT for motorcycles, including gear shifting, we developed theoretical equations. Conventional studies have often dealt with the theorization of constant speed states, and it has been difficult to predict the transmission efficiency because a theoretical analysis method for the behavior during gear shifting has not been established. We compared the results of calculations based on the developed theoretical equations with experimental results, demonstrating their effectiveness.

Development of Light-weight Final Drive for New Full-size SUV

Shiro Kono･Shin Hashimoto･Hiroaki Katase･Takayuki Asai･Masakatsu Koide･Kanta Fukumoto (Nissan Motor)

We developed a new final drive unit for a new full-size SUV. It consists of a high-efficiency and class-leading light-weight aluminum carrier. To address concerns about reduced rigidity due to aluminum, we applied snap rings to fix the differential side bearings, ensuring the same gear support rigidity as conventional cast iron housings. By adopting a low-offset hypoid gear and low-viscosity oil, and optimizing the housing shape for efficient heat dissipation, we achieved a compact design. Applying this new unit to an independent suspension axle enables premium-class ride comfort and quietness, with a towing capacity of 8,500 lbs and high fuel efficiency.

Flow Analysis of Lubricating Oil in a Rotating Environment

Hiroto Hayashi･Takuma Kato (Chiba Institute of Technology)

This study focuses on shaft core lubrication, the method of oil supply within the transmission, and examines it from the perspective of computational fluid dynamics (CFD) using the finite volume method. By altering the analysis conditions, changes in fluid behavior became evident, leading to variations in lubrication. The study aims to clarify the relationship with factors such as rotational speed, lubricant properties, and shape, with the goal of improving technology.

Flow-rate Characteristics of Lubricating Oil Flow around Discharge Hole in Rotating Shaft

Takuma Kato (Chiba Institute of Technology)

In delivering lubrication through a shaft of an automatic transmission, it is difficult to lubricate due to the effects of centrifugal force and agitation caused by rotation. To solve this problem, we investigated the behavior of gas-liquid two-phase flow in a rotating pipe. Through measurement of the flow rate and flow visualization, we designed the shape of the discharge hole to suppress the rotation speed sensitivity.

The Influence of Lubricant Friction Properties on the Efficiency of Electric Transaxle

Hiroyuki Tatsumi･Takashi Yanagihara･Yuki Okada･Keiichi Narita (Idemitsu Kosan)

The effect of friction characteristics of lubricants on the efficiency of transaxle for electric vehicles was investigated. Evaluation using a high-speed gear testing machine and an actual reduction gear revealed that the reduction of traction coefficient contributes most to efficiency improvement, and that friction properties in boundary and mixed lubrication are also effective in improving efficiency.