Patent US5629478A successfully refreshed from Google Patents.
US5629478A
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Method of and device for detecting tire pressure drop based on angular velocity
Assignee: Sumitomo Rubber Industries Ltd
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Filing: 1995-12-08
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Granted: 1997-05-13
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Expires: 2015-12-08
Abstract
Abstract A method of and a device for detecting a pneumatic pressure drop of tires provided for a vehicle are disclosed. Rotational angular velocities of tires are determined and a judged value D is determined based on the determined rotational angular velocities. A speed of the vehicle, a front/rear acceleration FRA of the vehicle, a lateral acceleration LA of the vehicle and a turning radius R of the vehicle are substituted into a predetermined polynominal expression which is defined so that an influence of the turning radius R is exerted on all terms to determine a correction value. A judged value D' after correction is determined by correcting the judged value D using the correction value. It is judged whether a tire pressure drops or not, based on the judged value D' after correction. In such way, a tire pressure drop can be detected, accurately, excluding an influence of the turning radius R of the vehicle.
Inventors
- 👤 Mikao Nakajima
- 👤 Isao Isshiki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:25
CPC Classifications
B; B60; B60C; B60C23/00; B60C23/06; B60C23/061
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
132 words
A method of determining a pneumatic pressure drop of a tire provided for a vehicle, comprising the steps of: determining a rotational angular velocity of a tire, determining a judged value D based on the determined rotational angular velocity; substituting a velocity V of the vehicle, a front/rear acceleration FRA of the vehicle, a lateral acceleration LA of the vehicle and a turning radius R of the vehicle into a predetermined polynominal expression to determine a correction value, the predetermined polynominal expression being defined so that an influence of the turning radius R is exerted on all terms; determining a judged value D' after correction by correcting the judged value D using the correction value; and judging whether a tire pressure drops or not, based on the judged value D' after correction.
Claim 2
Independent Claim
132 words
A method of determining a pneumatic pressure drop of a tire provided for a vehicle, comprising the steps of: determining a rotational angular velocity of a tire, determining a judged value D based on the determined rotational angular velocity; substituting a velocity V of the vehicle, a front/rear acceleration FRA of the vehicle, a lateral acceleration LA of the vehicle and a turning radius R of the vehicle into a predetermined polynominal expression to determine a correction value, the predetermined polynominal expression being defined so that an influence of the turning radius R is exerted on all terms; determining a judged value D' after correction by correcting the judged value D using the correction value; and judging whether a tire pressure drops or not, based on the judged value D' after correction.
Claim 3
Dependent Claim
30 words
A method according to claim 1, wherein the predetermined polynominal expression is the following equation (A) for determining a correction value C1: ##EQU17## wherein A1, A2 and A3 indicate constants.
Claim 4
Dependent Claim
30 words
A method according to claim 1, wherein the predetermined polynominal expression is the following equation (B) for determining a correction value C2: ##EQU18## wherein B1, B2 and B3 indicate constants.
Claim 5
Dependent Claim
29 words
A method according to claim 1, wherein the predetermined polynominal expression is the following equation (C) for determining a correction value C3: ##EQU19## wherein E1 and B2 indicate constants.
Claim 6
Dependent Claim
95 words
A method according to claim 1, wherein the predetermined polynominal expression has a term containing the front/rear acceleration of the vehicle, the method further comprising the steps of judging whether the vehicle is traveling with accelerated speed or traveling with decelerated speed, based on the front/rear acceleration of the vehicle, applying a first constant as a factor of the term including the front/rear acceleration when the vehicle is traveling with accelerated speed, and applying a second constant as the factor of the term including the front/rear acceleration when the vehicle is traveling with decelerated speed.
Claim 7
Dependent Claim
91 words
A method according to claim 1, wherein the vehicle is a four-wheel vehicle provided with four tires, wherein the step of determining the rotational angular velocity of a tire includes determining rotational angular velocities F2 1 , F2 2 , F2 3 and F2 4 of the four tires, and wherein the step of determining the judged value D includes substituting the rotational angular velocities F2 1 , F2 2 , F2 3 and F2 4 of the four tires into the following equation to determine the judged value D: ##EQU20##
Claim 8
Dependent Claim
163 words
A method according to claim 1, wherein the vehicle is a four-wheel vehicle provided with four tires, and wherein the step of determining the rotational angular velocity of a tire includes the steps of: calculating rotational angular velocities F 1 , F 2 , F 3 and F 4 of the four tires based on output signals of wheel speed sensors, correcting the rotational angular velocities F 1 , F 2 , F 3 and F 4 to calculate rotational angular velocities F1 1 , F1 2 , F1 3 and F1 4 in which an initial difference is corrected, and further correcting the rotational angular velocities F1 1 , F1 2 , F1 3 and F1 4 in which the initial difference is corrected, to calculate rotational angular velocities F2 1 , F2 2 , F2 3 and F2 4 in which variations caused by a difference in distance from a turning center of the vehicle to the respective tires are excluded.
Claim 9
Dependent Claim
99 words
A method according to claim 1, wherein the vehicle is a four-wheel vehicle provided with four tires, and wherein the step of determining the rotational angular velocity of a tire includes determining rotational angular velocities F2 1 , F2 2 , F2 3 and F2 4 of the four tires, the method further comprising a step of determining a speed of the vehicle V, a front/rear acceleration FRA of the vehicle and a lateral acceleration LA of the vehicle, based on rotational angular velocities F2 1 , F2 2 , F2 3 and F2 4 of the four tires.
Claim 10
Dependent Claim
28 words
A method according to claim 1, further comprising a step of determining a turning radius R, wherein an influence of a load movement of the vehicle is excluded.
Claim 11
Dependent Claim
29 words
A method according to claim 1, wherein the step of determining the judged value D' after correction includes subtracting the correction value from the judged value D before correction.
Claim 12
Dependent Claim
64 words
A method according to claim 1, wherein the step of judging whether the tire pressure drops or not includes a step of judging that a reduced pressure tire is not present if the judged value D' after correction is within a predetermined range and that a reduced pressure tire is present if the judged value D' after correction is not within the predetermined range.
Claim 13
Independent Claim
154 words
A device for determining a pneumatic pressure drop of a tire provided for a vehicle, comprising: rotational angular velocity operating means for determining a rotational angular velocity of a tire; judged value operating means for determining a judged value D based on the determined rotational angular velocity; correction value operating means for substituting a velocity V of the vehicle, a front/rear acceleration FRA of the vehicle, a lateral acceleration LA of the vehicle and a turning radius of the vehicle into a predetermined polynominal expression to determine a correction value, the predetermined polynominal expression being defined so that an influence of the turning radius R is exerted on all terms; judged value correcting means for determining a judged value D' after correction by correcting the judged value D using the correction value; and reduced pressure judging means for judging whether a tire pressure drops or not, based on the judged value D' after correction.
Claim 14
Independent Claim
154 words
A device for determining a pneumatic pressure drop of a tire provided for a vehicle, comprising: rotational angular velocity operating means for determining a rotational angular velocity of a tire; judged value operating means for determining a judged value D based on the determined rotational angular velocity; correction value operating means for substituting a velocity V of the vehicle, a front/rear acceleration FRA of the vehicle, a lateral acceleration LA of the vehicle and a turning radius of the vehicle into a predetermined polynominal expression to determine a correction value, the predetermined polynominal expression being defined so that an influence of the turning radius R is exerted on all terms; judged value correcting means for determining a judged value D' after correction by correcting the judged value D using the correction value; and reduced pressure judging means for judging whether a tire pressure drops or not, based on the judged value D' after correction.
Claim 15
Dependent Claim
30 words
A device according to claim 12, wherein the predetermined polynominal expression is the following equation (A) for determining a correction value C1: ##EQU21## wherein A1, A2 and A3 indicate constants.
Claim 16
Dependent Claim
30 words
A device according to claim 12, wherein the predetermined polynominal expression is the following equation (B) for determining a correction value C2: ##EQU22## wherein B1, B2 and B3 indicate constants.
Claim 17
Dependent Claim
29 words
A device according to claim 12, wherein the predetermined polynominal expression is the following equation (C) for determining a correction value C3: ##EQU23## wherein E1 and B2 indicate constants.
Claim 18
Dependent Claim
98 words
A device according to claim 12, wherein the predetermined polynominal expression has a term containing the front/rear acceleration of the vehicle, the device further comprising means for judging whether the vehicle is traveling with accelerated speed or traveling with decelerated speed, based on the front/rear acceleration of the vehicle, means for applying a first constant as a factor of the term including the front/rear acceleration when the vehicle is traveling with accelerated speed, and means for applying a second constant as the factor of the term including the front/rear acceleration when the vehicle is traveling with decelerated speed.
Claim 19
Dependent Claim
87 words
A device according to claim 12, wherein the vehicle is a four-wheel vehicle provided with four tires, wherein the rotational angular velocity operating means include means for determining rotational angular velocities F2 1 , F2 2 , F2 3 and F2 4 of the four tires, and wherein the judged value operating means includes means for substituting the rotational angular velocities F2 1 , F2 2 , F2 3 and F2 4 of the four tires into the following equation to determine the judged value D: ##EQU24##
Claim 20
Dependent Claim
162 words
A device according to claim 12, wherein the vehicle is a four-wheel vehicle provided with four tires, and wherein the rotational angular velocity operating means includes: means for calculating rotational angular velocities F 1 , F 2 , F 3 and F 4 of the four tires based on an output signal of wheel speed sensors, means for correcting the rotational angular velocities F 1 , F 2 , F 3 and F 4 to calculate rotational angular velocities F1 1 , F1 2 , F1 3 and F1 4 in which an initial difference is corrected, and means for further correcting the rotational angular velocities F1 1 , F1 2 , F1 3 and F1 4 in which the initial difference is corrected, to calculate rotational angular velocities F2 1 , F2 2 , F2 3 and F2 4 in which scatter caused by a difference in distance from a turning center of the vehicle to the respective tires is excluded.
Claim 21
Dependent Claim
95 words
A device according to claim 12, wherein the vehicle is a four-wheel vehicle provided with four tires, and wherein the rotational angular velocity operating means includes means for determining the rotational angular velocities F2 1 , F2 2 , F2 3 and F2 4 of the four tires, the device further comprising means for determining a speed of the vehicle, a front/rear acceleration FRA of the vehicle and a lateral acceleration LA of the vehicle, based on rotational angular velocities F2 1 , F2 2 , F2 3 and F2 4 of the four tires.
Claim 22
Dependent Claim
24 words
A device according to claim 12, further comprising means for determining a turning radius R wherein an influence of a load movement is excluded.
Claim 23
Dependent Claim
34 words
A device according to claim 12, wherein the judged value correcting means includes means for subtracting the correction value from the judged value D before correction to determine a judged value D' after correction.
Claim 24
Dependent Claim
56 words
A device according to claim 12, wherein the reduced pressure judging means includes means for judging that a reduced pressure tire is not present if the judged value D' after correction is within a predetermined range and a reduced pressure tire is present if the judged value D' after correction is not within the predetermined range.
References Cited (Backward Citations)
JPS63305011A
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JPH04212609A
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EP0466535A1
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EP0489562A1
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US5248957A
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EP0564285A1
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JPH07164842A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-05-12 | 2000-11-11 | 2001-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-05-12 | 2004-11-11 | 2005-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-05-12 | 2008-11-11 | 2009-05-13 | $7700.00 | Window Closed / Lapsed |