- Research and Development
Magneto-rheological fluid (MR fluid)
This technology can change the viscosity of a fluid by means of magnetic force. It is expected to be applied to the field of machine control, such as robots.
What is a magneto-rheological fluid (MR fluid)?
MR fluid refers to a fluid in which magnetic particles, such as those of steel, are dispersed in a base fluid, such as oil. Its viscosity changes by applying a magnetic field from outside. By applying a dispersion technology that has been refined over many years of operation, we have achieved stable dispersion of magnetic particles (diameter: several to 50 μm), which can demonstrate large stress, over a long period. Long-term stable dispersion has been achieved over a wide range of magnetic particle concentrations, and the output can be changed over a broad range.
Click/tap here to watch a video that shows the characteristics of the technology.
What are the key features of this technology?
Before a magnetic field is applied, an MR fluid behaves like a liquid because particles are uniformly dispersed. When a magnetic field is applied, magnetic particles are arrayed in a certain direction along the magnetic field. This increases the viscosity of the MR fluid, which behaves like a solid. When the application of a magnetic field is stopped, the solid state returns to the liquid state. Stable dispersion of magnetic particles using a special base fluid and the lifting effect derived from adding nanoparticles, which are smaller than the magnetic substances, have reduced the precipitation and coagulation of magnetic particles and achieved long-term stable dispersion.
Contribution to solving social issues
We have developed an MR fluid characterized by high dispersion stability. Due to a wide range of output, this material can improve the speed reduction ratio and backdrivability of brakes and actuators and simplify the systems, making it possible to improve the performance and cut costs of existing devices. Application of this material to actuators of robots can attain high backdrivability. Safe cobots can be manufactured. The material is also expected to be used in a wide range of fields, such as medical equipment, haptics, and VR, by taking advantage of precise and agile viscosity control.