Various decarbonization efforts are made by industrial companies with a view to realizing carbon neutrality in 2050. As the importance of saving fuel consumption increases in products including automobiles, tribological technologies contributing to the development of sealing products are expected. Sealing products make a contribution to equipment efficiency in total despite small frictional effect in each sealing part. In rubber and plastic seals, the improvement of designs and materials is required for maintaining both stable sealing performance and high durability, as well as providing additional values such as friction reduction, bio-basing, electrical conductivity, and noise reduction. This paper describes the technical topics in rubber and plastic seals with focusing on the target for carbon neutrality.

To realize “Carbon neutral”by 2050, low leakage and low friction seal which supports to obtain high efficiency and “Zero-emission”could take one of important part. In this paper, recent trends of surface texturing technology on mechanical seals and some examples which textured mechanical seals were applied in EV motor cooling, turbo-pump of cryogenic fluid for rocket engine and generator with renewable energy were introduced. Surface texturing technology supplied solution of trade-off problem between friction and leakage and the technology has potential to evolve mechanical seals to next generation’s one. In practical use, the technology has been applied to mechanical seals and has been realized low friction and low leakage for contributing to realize carbon neutral.

The present article introduces running-test results of plastic internal gears with the method for evaluating the load capacity of plastic gears prescribed in JIS B 1759 and shows controversial issues in the standard. Combined with the twin-disc-test results of plastic rollers, these discussions raise the expectations of plastic internal gears with much higher load capacity, which allow them to play an important role in electric vehicles.

John Ramsbottom invented the metal piston ring during the Industrial Revolution. With the invention of the piston ring, the internal combustion engine remains the primary source of power today. After John Ramsbottom’s invention, the research for a piston rings developed in Japan. For a time in the past, Japanese cars were rated as the cheapest and most efficient in the world. Among the many studies, the correlation between running-in and piston ring function is particularly important. This article briefly summarizes the background.

Wet clutches are mainly used in automobile automatic transmissions. To reduce greenhouse gas emissions, it is important to improve the fuel efficiency of automobiles. Wet clutches are required to reduce the drag torque when the clutch is disengaged. Drag torque varies greatly depending on the design of the clutch plates, represented by the shape of the friction material segment pieces. It will be explained the efforts to reduce drag torque related to the design of friction plates.

A method to predict tire tread wear in the laboratory was introduced based on low severity tire wear mechanism. The tire acceleration distribution was used to determine slip ratio of the test. Sample load was determined using sample dynamic contact area and tire inflation pressure. The laboratory test result based on the established condition was in good agreement with the tire test result. The author found three types of high frequency vibration that was most likely the driver for wear.

The EHL film thickness decreases in reducing the entrainment speed, but with grease, it increases again after passing a minimum. This behavior was revealed in preceding works, which showed that it was caused by the increase in the viscosity of grease due to that in thickener concentration. The present work starts with the measurement of oil separation from grease by centrifuging, and its result is interpreted to the permeability as a function of the thickener concentration by employing a modified Kozeny-Carman equation. The permeability is then used as a key factor governing the Darcy flow of base oil through thickener network in a numerical analysis of the grease flow by taking it as a two-phase flow of base oil and thickener, and its result shows reasonable agreement with that of experiments by the optical interferometry. On this basis, the changes in the thickener concentration and the permeability in the inlet region to the EHL contact is discussed, and a chart showing the relation between the minimum film thickness and the initial permeability of the greases is developed, which will serve as a guide map for selecting a grease to have the desired thick EHL film formation characteristics.

In order to understand motion mechanisms of slippers in swash plate type piston pumps, the analysis flow combining multi-body dynamics and the oil-film analysis was constructed. This analysis evaluated the effects of elastic deformation of the retainer on the slipper behavior. The retainer is deformed by the spring force so that the outer circumference of the retainer is tilted by about 20 µm. Due to this deformation, the analysis result was obtained in which the center displacement of the slipper was reduced and the tilt angle was increased. Deformation of the retainer has a great effect on the behavior of slippers.