System for detecting abnormality in internal pressure of tire

• US 4,376,931 A
• Filed: 09/18/1980
• Issued: 03/15/1983
• Est. Priority Date: 02/07/1980
• Status: Expired due to Term

• Current Assignee: Meisei Electric Co., Ltd. (IHI Corporation)
• Original Assignee: Meisei Electric Co., Ltd. (IHI Corporation)
• Inventors: Takahashi, Hiroshi, Yamamoto, Masanobu, Kobane, Sumio, Komatu, Satoru, Izumo, Terutsugu
• Primary Examiner(s): Caldwell, Sr., John W.
• Assistant Examiner(s): Nowicki, Joseph E.
• Application Number:
  US06/188,590
• Time in Patent Office: 908 Days
• Field of Search: 340/58, 340/539, 200/61.22, 200/61.25
• US Class Current: 340/447
• CPC Class Codes: B60C 23/007 having multiple wheels arranged side by side
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver

Abstract

A detection system for detecting abnormality in the internal air pressure of a tire of a motor vehicle produces an alarm upon detection of an abnormal change in the air pressure of the tire. The system comprises a first device which is disposed at a wheel (or a rotating part) of the motor vehicle and has an abnormal pressure detecting means using a crystal resonator and an antenna for sending out detection information in the air; and a second device which is disposed for example in the vicinity of a driver'"'"'s seat (or at a non-rotating part) and has a transmitter/receiver arrangement provided with an antenna. The crystal resonator is driven by an exciting energy sent out from the transmission part of the transmitter/receiver. Immediately after ceasing of the exciting energy from being sent out, a signal is discharged from the crystal resonator by an oscillatory energy accumulated at the above stated resonator and is received by the receiving part of the transmitter/receiver to show abnormality in the internal pressure of the tire if there is any. The crystal resonator is either used solely as information (abnormal decrease of air pressure in the tire) transmitting means in combination with an abnormality detecting switch (a pressure responsive element) or used also for abnormal pressure detection as well as for transmission of the information.

Claims

1. A system for detecting abnormality in the internal pressure of a tire having a first device disposed at a wheel which includes said tire and a second device disposed at a non-rotating part, said system comprising in combination:

a. the first device which includes;

a-1. a pressure responsive element which is provided with a crystal resonator, said element being arranged to operate to cause a stress applied to said crystal resonator to be varied by variations of the internal pressure of said tire and thus to vary the natural frequency of the crystal resonator accordingly, and

a-2. a first antenna connected to said pressure responsive element; and

b. the second device which includes;

b-1. a transmitter arranged to excite said crystal resonator by sending out one after another therefrom a plurality of different exciting energies having different frequency values within a range over which the natural frequency of said crystal resonator varies when the internal pressure of the tire is within a normal range thereof,

b-2. a receiver arranged to receive an oscillatory energy which is discharged from the crystal resonator immediately after said excitation of the crystal resonator by the exciting energy from said transmitter comes to a stop with the oscillatory energy accumulated by the exciting energy at the crystal resonator and discharged therefrom immediately after the ceasing of said exciting action on the crystal resonator,

b-3. a second antenna connected to said transmitter and receiver, the second antenna being arranged to send said exciting energy to said first antenna and to receive said discharged oscillatory energy from said first antenna,

b-4. a switch-over circuit arranged to stop the exciting energy sending out action of said transmitter after the exciting energy is sent out from the transmitter and to allow said receiver to begin the receiving action thereof, and

b-5. an alarm circuit connected to said receiver, said alarm circuit being arranged to announce abnormality when the abnormality is detected by the receiver, the abnormality being determined on the basis that the oscillation frequency of the discharged oscillatory energy comes outside of a preset range of oscillation frequency.

2. A system according to claim 1, wherein the internal pressure of said tire is constantly monitored with said switch-over circuit arranged to operate in a repeating manner.

3. A system according to claim 1, wherein said first antenna is formed into a loop-like shape and is disposed round the rim base of said wheel;

and said second antenna is formed also into a loop-like shape and is disposed at a non-rotating part in the vicinity of said rim base, said second antenna being arranged in a concentric circular manner with said first antenna.

4. A system for detecting abnormality in the internal pressure of tires having a first device disposed at each of a plurality of wheels including tires and a second device disposed at a non-rotating part, said system comprising:

a. each of said first devices, which includes;

a-1. a pressure responsive element which is provided with a crystal resonator, said element being arranged to operate to cause a stress applied to said crystal resonator to be varied by variations of the internal pressure of said tire and thus to vary the natural frequency of the crystal resonator accordingly, and

a-2. a first antenna connected to said pressure responsive element; and

b. said second device, which includes;

b-1. a transmitter arranged to excite said crystal resonator by sending out one after another therefrom a plurality of different exciting energies having different frequency values within a range over which the natural frequency of said crystal resonator varies when the internal pressure of the tire is within a normal range thereof,

b-2. a receiver arranged to receive an oscillatory energy which is discharged from the crystal resonator immediately after said excitation of the crystal resonator by the exciting energy from said transmitter comes to a stop with the oscillatory energy accumulated by the exciting energy at the crystal resonator and discharged therefrom immediately after the ceasing of said exciting action on the crystal resonator,

b-3. second antennas provided for said plurality of wheels, each of said second antennas being connected to said transmitter and receiver, each second antenna being arranged to send said exciting energy to said first antenna and to receive said discharged oscillatory energy from said first antenna of a corresponding first device disposed at one of said plurality of wheels,

b-4. A switch-over circuit arranged to stop the exciting energy sending out action of said transmitter after the exciting energy is sent out from the transmitter and to allow said receiver to begin the receiving action thereof,

b-5. an antenna switch-over circuit arranged to switch over the connection of at least the transmitter with the second antennas from one of said second antennas to another at the end of every cycle of the switching action of said switch-over circuit, and

b-6. an alarm circuit connected to said receiver, said alarm circuit being arranged to announce abnormality of each individual wheel when the abnormality thereof is detected by the receiver, the abnormality being determined on the basis of that the oscillation frequency of the discharged oscillatory energy comes outside of a preset range of oscillation frequency.

5. A system according to claim 4, wherein the internal pressure of said tires is constantly monitored with said switch-over circuit and said antenna switch-over circuit arranged to operate in a repeating manner respectively.

6. A system according to claim 4, wherein the crystal resonators of said first devices disposed at a plurality of wheels located in the same place are arranged to have different mid values of natural frequency from each other;

and said transmitter of said second device is arranged to send out one after another a plurality of exciting energies of different frequency values with frequency values equal to said different natural frequency values respectively set in the middle of frequency range thereof.

7. A system according to claim 4, wherein each of said first antenna is formed into a loop-like shape and is disposed round the rim base of said wheel;

and each of said second antenna is formed also into a loop-like shape and is disposed at a non-rotating part in the vicinity of said rim base, said second antenna being arranged in a concentric circular manner with said first antenna.