Research

The development of electrified construction equipment driven by electric motors is underway to achieve carbon neutrality. One of the challenges in electrification is the cost of electricity. In this research, we are improving the performance of hydraulic equipment suitable for electrified construction machinery so that it can operate with less power consumption.

As part of the worldwide efforts toward carbon neutrality, the electrification of equipment, as typified by electric vehicles, is rapidly progressing. One of the issues that arise when actually operating such equipment is the heat generated by electrical energy conversion loss and the dissipation of Joule heat. We have focused on the heat generation problem specific to construction machinery and are working on developing thermal design technology that achieves excellent heat dissipation.

A swash plate axial piston pump is a hydraulic pump that supplies hydraulic oil to a hydraulic motor or cylinder. This pump has sliding parts where metal parts rub against each other. In this research, the oil film thickness distribution between the slipper and swash plate under severe sliding conditions is measured using a fluorescent method to optimize the design of the sliding parts.

Generally, thermal resistance exists at the interface where two objects come into contact. It is said that the value of thermal resistance at an interface varies depending on the size and shape of the gap between the two objects, as well as the chemical affinity between the two objects, but the details are still unknown. Through experiments and simulations, we aim to clarify the factors that affect the heat that passes through the interface.

ZnDTP (zinc dialkyl dithiophosphate) is an additive used in many lubricants, such as engine oil, and is known to protect sliding surfaces by forming a tribofilm of sulfide layers and polyphosphate films. While most ZnDTP tribofilm studies have been conducted on specimens with very smooth surfaces, this study investigates the relationship between the formation behavior of ZnDTP tribofilms and tribological properties of sliding surfaces with surface roughness close to that of actual machine parts.

By applying a nanoink in which metal nanoparticles are dispersed in a solvent onto a substrate and then applying an appropriate heat treatment, the functions of the substrate surface can be controlled. For example, the wettability of a copper nanoparticle layer formed on a copper substrate changes depending on the oxidation state and roughness of the nanoparticle layer surface. We are investigating the effect of heat treatment on the change in wettability of the copper nanoparticle layer surface on phase change phenomena such as boiling and condensation.