μ GRADIENT DETECTION DEVICE, INSTALLATION TIRE DETERMINATION DEVICE, ROAD SURFACE STATE DETERMINATION DEVICE, INSTALLATION TIRE AND ROAD SURFACE STATE DETERMINATION DEVICE

摘要

PROBLEM TO BE SOLVED: To determine a road surface state, particularly, the occurrence of hydro-planing, and to determine a classification of an installation tire, without installing an acceleration sensor on a tire.;SOLUTION: A μ gradient detection device 30 comprises a detection part 32 for detecting vibration of a vehicle, a storage part 34 for storing a vehicle vibration characteristic with a μ gradient as a parameter and a μ gradient detection part 36 for detecting reduction in the μ gradient by collating the detected vibration and the vehicle vibration characteristic. An installation tire determination part 40 determines that a studless tire is installed when detecting reduction in the μ gradient when a vehicle speed detected by a vehicle speed detection part 38 is less than a hydro-planing occurrence vehicle speed. When a vehicle speed detected by the vehicle speed detection part 38 is the hydro-planing occurrence vehicle speed or more, a determination is made that hydro-planing is caused when detecting reduction in the μ gradient in a studless tire uninstallation.;SELECTED DRAWING: Figure 6;COPYRIGHT: (C)2019,JPO&INPIT