Tire-pressure sensor unit, a tire-pressure notification device, and vehicle

A tire-pressure sensor unit being fixed to and disposed on a wheel of a vehicle and comprising:

• a pneumatic sensor which detects a tire pressure,
• an acceleration sensor which detects acceleration generated by rotation of a wheel,
• a transmitter for transmitting wheel information which is information including tire-pressure information representing the tire pressure detected by said pneumatic sensor and an inherent sensor ID as a radio signal,
• a processor and memory configured to control a transmission timing of said wheel information by said transmitter based on the acceleration detected by said acceleration sensor, and
• a battery disposed as an internal electrical power source for the tire-pressure sensor unit,
• wherein;
• said processor and memory are configured to:
• in a first transmission process, make said transmitter periodically transmit said wheel information when the acceleration detected by said acceleration sensor is larger than a running-judgment threshold value,
• accumulate an acceleration-correlated amount which is correlated with the magnitude of the acceleration detected by said acceleration sensor and acquiring an accumulated value thereof when said acceleration is not more than said running-judgment threshold value,
• in a second transmission process, make said transmitter transmit said wheel information when said processor determines that there is a track record that said vehicle has run based on the comparison result between said acquired accumulated value and a running-track-record-judgment threshold value.