Tire pneumatic pressure detector

• US 20020089417A1
• Filed: 12/20/2001
• Published: 07/11/2002
• Est. Priority Date: 01/10/2001
• Status: Active Grant

• Current Assignee: DENSO Corporation, Daihatsu Motor Company Limited (Toyota Motor Corporation)
• Original Assignee: DENSO Corporation, Daihatsu Motor Company Limited (Toyota Motor Corporation)
• Inventors: Tanaka, Osamu, Makino, Nobuhiko, Hatoh, Takeshi, Matsuki, Takumo, Watanabe, Takashi, Taguchi, Takeyasu
• Granted Patent: US 6,720,869 B2
• Time in Patent Office: Days
• US Class Current: 340/442
• CPC Class Codes: B60C 23/0401 characterised by the type of alarm
• CPC Class Codes: B60C 23/061 by monitoring wheel speed measuring distance traversed on the ground by vehicles G01C22/00

Abstract

Data about a running distance from a time at which the drop of a tire pneumatic pressure occurs is stored, and a warning method of an alarm is changed in accordance with this data. For example, when the running distance is smaller than a predetermined value, a flashing frequency of an alarm lamp provided to the alarm is set to a lower frequency, and when the running distance becomes greater than the predetermined value, the flashing frequency of the alarm lamp is set to a higher frequency. When a fault-diagnosing device is connected to a tire pneumatic pressure detector, the data about the running distance from the timing of the occurrence of the drop of the tire pneumatic pressure can be read out. In consequence, the tire pneumatic pressure detector can judge the degrees of blowout and the drop of the pneumatic pressure. Further, market data about the blowout of the tire and the running after the drop of the pneumatic pressure can be collected.

Claims

1. A tire pneumatic pressure detector comprising:

tire pneumatic pressure detection means (S220) for detecting a tire pneumatic pressure;

pneumatic pressure drop detection means (S230) for comparing the tire pneumatic pressure detected by said tire pneumatic pressure detection means with a predetermined value, and detecting the drop of the tire pneumatic pressure when the tire pneumatic pressure is lower than the predetermined value; and

first memory means (S250) for storing data about a timing at which the drop of the tire pneumatic pressure occurs.

2. A tire pneumatic pressure detector according to claim 1, which further comprises:

second memory means (S370) for storing the lapse of time from said timing at which the drop of the tire pneumatic pressure occurs, or data about a running distance from said timing.

3. A tire pneumatic pressure detector according to claim 2, which further comprises:

an alarm (6) for warning about the drop of the tire pneumatic pressure when the drop of the tire pneumatic pressure occurs;

wherein said alarm changes a warning method in accordance with the lapse of time from the timing of the drop of the pneumatic pressure stored in said second memory means or the data about the running distance from said timing.

4. A tire pneumatic pressure detector according to claim 2 or 3, wherein said alarm warns about the drop of the tire pneumatic pressure by means of an alarm lamp, and increases a flashing frequency of said alarm lamp to a higher frequency for a longer lapse of time or a longer running distance than a shorter lapse of time or a shorter running distance on the basis of the lapse of time from the timing of the drop of the tire pneumatic pressure or the data about the running distance from said timing stored in said second memory means.

5. A tire pneumatic pressure detector according to any one of claims 2 through 4, which further comprises:

switching number of times detection means (S340) for detecting a switching number of times of ON/OFF of an ignition switch;

wherein, when the number of times of switching detected by said switching number of times detection means is greater than a predetermined number of times when said tire pneumatic pressure drop detection means detects that the tire pneumatic pressure is higher than said predetermined value, the data stored in said second memory means is cleared.

6. A tire pneumatic pressure detector according to any one of claims 2 through 4, wherein, when a fault-diagnosing device (7) inputs a fault diagnosis signal, the lapse of time from the timing at which the drop of the tire pneumatic pressure occurs or data about the running distance from the timing is outputted to said fault-diagnosing device.