Abstract: Provided is a replacement necessity determination device for a snap-in valve having an inner end to which an air pressure detection device including an air pressure sensor and an acceleration sensor is coupled. A control device of the replacement necessity determination device is configured to predict an angle change amount of the snap-in valve and the air pressure detection device with respect to a wheel caused by a centrifugal force based on a rotational speed of the wheel and an acceleration detected by the acceleration sensor, calculate a degradation indication value of an elastic body of the snap-in valve based on a maximum value of the angle change amount during a period set in advance, and determine necessity of replacement of the snap-in valve based on an integrated value of the degradation indication value.

Abstract: A tire pressure detector includes: an air pressure detector to repeatedly detect air pressure of a target tire; a transmission device to wirelessly transmit air pressure information about the air pressure detected by the air pressure detector; a reception device to receive the air pressure information transmitted by the transmission device; an estimation device to calculate, when the reception device receives the air pressure information on the identical target tire a plurality of times, an estimated air pressure based on a plurality of pieces of the latest air pressure information received by the reception device, the estimated air pressure being an estimated value of the air pressure at current time; and an alarm generation device to raise an alarm when the estimated air pressure becomes equal to or less than a specified threshold.

Abstract: It should be enabled to transmit tire-pressure information also on a spare wheel to a tire-pressure notification device, while suppressing battery consumption. A transmission controller of a sensor unit makes a transmitter periodically transmit wheel information, when an acceleration Gx detected by an acceleration sensor is larger than a running-judgment threshold value 5G. The transmission controller accumulates a point P set up according to the acceleration Gx in a predetermined period when the acceleration Gx is not more than the running-judgment threshold value 5G, and makes the transmitter transmit the wheel information when an accumulated value of the point P accumulated in the predetermined period is larger than a running-track-record-judgment threshold value.

Abstract: A tire pressure detector includes: an air pressure detector to repeatedly detect air pressure of a target tire; a transmission device to wirelessly transmit air pressure information about the air pressure detected by the air pressure detector; a reception device to receive the air pressure information transmitted by the transmission device; an estimation device to calculate, when the reception device receives the air pressure information on the identical target tire a plurality of times, an estimated air pressure based on a plurality of pieces of the latest air pressure information received by the reception device, the estimated air pressure being an estimated value of the air pressure at current time; and an alarm generation device to raise an alarm when the estimated air pressure becomes equal to or less than a specified threshold.

Abstract: A pulse count part acquires the minimum value among the numbers of pulse signals outputted by respective wheel-speed sensors during a wheel speed is within a minute low speed range. The pulse count part sets said minimum value as the numbers of the pulse signals of respective wheel-speed sensors during the wheel speed is within the minute low speed range, when the wheel speed increases out of said minute low speed range. Thereby, even when a vehicle stops in the middle of a wheel location discrimination treatment, a wheel location discrimination treatment can be continued using a proper pulse count value.

Abstract: A warning control unit of this tire air pressure monitoring device starts giving a driver a tire air pressure fall warning when a tire air pressure is equal to or lower than a first threshold. The warning control unit stops the warning when the tire air pressure becomes equal to or higher than a second threshold that is set based on a tire temperature in a case where the warning is being given. The warning control unit uses a constant value unrelated to a detected tire temperature as the first threshold, and uses a value obtained by adding a variable value, which is obtained by adding a positive constant value to a value that increases as a temperature difference obtained by subtracting a tire temperature at the time of the issuance of the warning from a current tire temperature increases, to the first threshold, as the second threshold.

Abstract: Provided is a replacement necessity determination device for a snap-in valve having an inner end to which an air pressure detection device including an air pressure sensor and an acceleration sensor is coupled. A control device of the replacement necessity determination device is configured to predict an angle change amount of the snap-in valve and the air pressure detection device with respect to a wheel caused by a centrifugal force based on a rotational speed of the wheel and an acceleration detected by the acceleration sensor, calculate a degradation indication value of an elastic body of the snap-in valve based on a maximum value of the angle change amount during a period set in advance, and determine necessity of replacement of the snap-in valve based on an integrated value of the degradation indication value.

Abstract: A warning control unit of this tire air pressure monitoring device starts giving a driver a tire air pressure fall warning when a tire air pressure is equal to or lower than a first threshold. The warning control unit stops the warning when the tire air pressure becomes equal to or higher than a second threshold that is set based on a tire temperature in a case where the warning is being given. The warning control unit uses a constant value unrelated to a detected tire temperature as the first threshold, and uses a value obtained by adding a variable value, which is obtained by adding a positive constant value to a value that increases as a temperature difference obtained by subtracting a tire temperature at the time of the issuance of the warning from a current tire temperature increases, to the first threshold, as the second threshold.

Abstract: [Objective] Unreceived malfunction should be prevented from being reported, at the time of a set replacement of tires. [Means for Solution] About each registered sensor ID, the unreceived malfunction judging portion 56 outputs a malfunction signal to the notification controller 53, when an unreceived period exceeds first setup time Tref1. The total unreceived period calculation portion 57 outputs a self-vehicle ID discrimination initiation instruction to ID discrimination/rewriting portion, when the sum total unreceived period Ttotal which is the sum total of the unreceived period of each registered sensor ID is calculated and the sum total unreceived period Ttotal exceeds second setup time Tref2. Before an unreceived period exceeds first setup time Tref1, registered sensor ID is rewritten and it can avoid reporting unreceived malfunction to a driver by this.

Abstract: A tire-pressure information device should receive wheel information within a demanded detection time. A transmission controller of a sensor unit transmits wheel information as a radio signal at the timing when the turning position ? of the sensor unit detected by an acceleration sensor arrives at the transmission setting location ? after 1 minute has passed since the last transmission of the wheel information. This transmission setting location ? is set to a turning position which is advanced or retarded a setting adjustment angle ?? (for instance, 146 degree) set to a value which is not a divisor of 360, with respect to the turning position ? when the last wheel information is transmitted last time.

Abstract: A vehicle wheel information acquiring device includes a vehicle wheel sensor and a vehicle-body-side device. The vehicle wheel sensor is configured to revolve around an axle with a rotation of a vehicle wheel. The vehicle-body-side device includes a reception unit, a processing unit, a rotation position acquiring unit, an on-reception rotation position storage unit, and a determination unit. The determination unit is configured to determine whether a revolution position of the vehicle wheel sensor is included in an insufficient received intensity area during a stopping operation of a vehicle.

Abstract: [Objective] Unreceived malfunction should be prevented from being reported, at the time of a set replacement of tires. [Means for Solution] About each registered sensor ID, the unreceived malfunction judging portion 56 outputs a malfunction signal to the notification controller 53, when an unreceived period exceeds first setup time Tref1. The total unreceived period calculation portion 57 outputs a self-vehicle ID discrimination initiation instruction to ID discrimination/rewriting portion, when the sum total unreceived period Ttotal which is the sum total of the unreceived period of each registered sensor ID is calculated and the sum total unreceived period Ttotal exceeds second setup time Tref2. Before an unreceived period exceeds first setup time Tref1, registered sensor ID is rewritten and it can avoid reporting unreceived malfunction to a driver by this.

Abstract: It should be enabled to transmit tire-pressure information also on a spare wheel to a tire-pressure notification device, while suppressing battery consumption. A transmission controller of a sensor unit makes a transmitter periodically transmit wheel information, when an acceleration Gx detected by an acceleration sensor is larger than a running-judgment threshold value 5G. The transmission controller accumulates a point P set up according to the acceleration Gx in a predetermined period when the acceleration Gx is not more than the running-judgment threshold value 5G, and makes the transmitter transmit the wheel information when an accumulated value of the point P accumulated in the predetermined period is larger than a running-track-record-judgment threshold value.

Abstract: A tire-pressure information device should receive wheel information within a demanded detection time. A transmission controller of a sensor unit transmits wheel information as a radio signal at the timing when the turning position ? of the sensor unit detected by an acceleration sensor arrives at the transmission setting location ? after 1 minute has passed since the last transmission of the wheel information. This transmission setting location ? is set to a turning position which is advanced or retarded a setting adjustment angle ?? (for instance, 146 degree) set to a value which is not a divisor of 360, with respect to the turning position ? when the last wheel information is transmitted last time.

Abstract: A pulse count part acquires the minimum value among the numbers of pulse signals outputted by respective wheel-speed sensors during a wheel speed is within a minute low speed range. The pulse count part sets said minimum value as the numbers of the pulse signals of respective wheel-speed sensors during the wheel speed is within the minute low speed range, when the wheel speed increases out of said minute low speed range. Thereby, even when a vehicle stops in the middle of a wheel location discrimination treatment, a wheel location discrimination treatment can be continued using a proper pulse count value.

Abstract: A vehicle wheel information acquiring device includes a vehicle wheel sensor and a vehicle-body-side device. The vehicle wheel sensor is configured to revolve around an axle with a rotation of a vehicle wheel. The vehicle-body-side device includes a reception unit, a processing unit, a rotation position acquiring unit, an on-reception rotation position storage unit, and a determination unit. The determination unit is configured to determine whether a revolution position of the vehicle wheel sensor is included in an insufficient received intensity area during a stopping operation of a vehicle.

Abstract: A rotation angle velocity is acquired in each of a two-wheel high pressure state and a reference state of air pressures of respective four wheels, and a rotation angle velocity value and a resonant frequency are acquired. The rotation angle velocity value, etc, acquired in the two-wheel high pressure state and the rotation angle velocity value, etc, acquired in the reference state are compared with each other. When these values are generally equal to each other, it is determined that at least one of the values is not appropriate for the determination of the malfunction determination threshold value, and a preset value is determined to be used as the malfunction determination threshold value. When these values are different from each other, the malfunction determination threshold value is determined. The determination of the malfunction determination threshold value to an inappropriate value is thus avoided, reliably monitoring the air pressures.

Abstract: A wheel state monitoring system monitors the state of a wheel using a transmitter that wirelessly transmits a signal containing wheel information on the wheel and a receiver that receives the signal and estimates the state of the wheel based on the wheel information. According to a method for inspecting the wheel state monitoring system, it is determined whether the wheel information is appropriately transmitted from the transmitter and received by the receiver. The inspection is performed in a communication state in which it is more difficult for the receiver to receive, as the wheel information, a signal transmitted from the transmitter than in a state of communication between the transmitter and the receiver, which is selected at normal times when the wheel state monitoring system monitors the state of the wheel.

Abstract: A tire trouble detection device detects occurrence of a trouble in a tire. The tire trouble detection device comprises a detection unit which detects a change of state of a layered composition portion arranged in layers inside an outer sheath forming an outside surface of the tire, the layered composition portion forming a frame of the tire. A determination unit receives a result of the detection from the detection unit and determines occurrence of a trouble of the layered composition portion based on the received result of the detection.

Abstract: A wheel-side device transmits wheel information that includes the state of air pressure detected by an air pressure sensor. The information is received by a vehicle body-side device. A value of air pressure is obtained on the basis of the wheel information received by the vehicle body-side device. If during supply of air pressure to the tire, the air pressure value reaches a target value, a lamp provided on the outside of the vehicle body is flickered in a pattern A. Of the air pressure value reaches the target value+?, the lamp is flickered in a pattern B. Therefore, an operating person outside the vehicle will learn about the air pressure of the tire and therefore about the state of operation of supplying air pressure, on the basis of the state of flicker of the lamp.