US4840243A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Four-wheel steering vehicle
Assignee: Mazda Motor Corp
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Filing: 1988-08-30
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Granted: 1989-06-20
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Expires: 2008-08-30
Abstract
Abstract A four-wheel steering vehicle including a four-wheel steering mechanism for controlling a steering of front and rear wheels based on a predetermined steering ratio property in accordance with an operation of a steering wheel, and an anti-lock braking system for controlling a braking force acted on each of the front and rear wheels to prevent the wheels from locking during a braking operation. The vehicle further comprises a stepping motor for controlling a steering ratio of a steering amount of the rear wheels to a steering amount of the front wheels in accordance with a vehicle speed based on said steering ratio property, fail detecting device for detecting an abnormal condition of the anti-lock braking system, compensating device for receiving signals from the fail detecting device and compensating the steering ratio property so that the rear wheels are steered in a direction and amount to improve a driving stability of the vehicle during a braking operation.
Inventors
- 👤 Shigefumi Hirabayashi
- 👤 Toshio Nakajima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:33
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/17; B60T8/1755; B62; B62D; B62D7/00; B62D7/06; B62D7/14; B62D7/148; B62D7/15; B62D7/1518; B62D7/1536; B62D7/1545; B60T2260/00; B60T2260/02; B60T2260/022
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
156 words
A four-wheel steering vehicle including a four-wheel steering mechanism for controlling a steering of front and rear wheels based on a predetermined steering ratio property in accordance with an operation of a steering wheel, and- an anti-lock braking system for controlling a braking force acted on each of the front and rear wheels to prevent the wheels from locking during a braking operation, the improvement comprising steering ratio changing means for controlling a steering ratio of a steering amount of the rear wheels to a steering amount of the front wheels in accordance with a vehicle speed based on said steering ratio property, fail detecting means for detecting an abnormal condition of the anti-lock braking system, compensating means for receiving signals from the fail detecting means and compensating the steering ratio property so that the rear wheels are steered in a direction and amount to improve a driving stability of the vehicle during a braking operation.
Claim 2
Dependent Claim
156 words
A four-wheel steering vehicle including a four-wheel steering mechanism for controlling a steering of front and rear wheels based on a predetermined steering ratio property in accordance with an operation of a steering wheel, and- an anti-lock braking system for controlling a braking force acted on each of the front and rear wheels to prevent the wheels from locking during a braking operation, the improvement comprising steering ratio changing means for controlling a steering ratio of a steering amount of the rear wheels to a steering amount of the front wheels in accordance with a vehicle speed based on said steering ratio property, fail detecting means for detecting an abnormal condition of the anti-lock braking system, compensating means for receiving signals from the fail detecting means and compensating the steering ratio property so that the rear wheels are steered in a direction and amount to improve a driving stability of the vehicle during a braking operation.
Claim 3
Dependent Claim
49 words
A four-wheel steering vehicle in accordance with claim 1 wherein the anti-lock braking system stops controlling the braking force during the braking operation in an abnormal condition of the anti-lock braking system so that each of the wheels are braked in accordance with a stroke of a brake pedal.
Claim 4
Dependent Claim
31 words
A four-wheel steering vehicle in accordance with claim 2 wherein both the four-wheel steering mechanism and the anti-lock braking system are controlled based on the signals from the fail detecting means.
Claim 5
Dependent Claim
66 words
A four-wheel steering vehicle in accordance with claim 1 wherein the improvement further comprises a speed reduction rate detecting means for detecting a reduction rate of the vehicle speed, the compensating means being actuated when the fail detecting means detects an abnormal condition of the anti-lock braking system and the speed reduction rate detecting means detects a vehicle speed reduction rate more than a predetermined value.
Claim 6
Dependent Claim
29 words
A four-wheel steering mechanism in accordance with claim 4 wherein the speed reduction rate detecting means is a brake switch which is actuated when a brake pedal is operated.
Claim 7
Dependent Claim
32 words
A four-wheel steering mechanism in accordance with claim 4 wherein the compensating means is maintained at an operating condition once a vehicle speed reduction rate more than the predetermined value is detected.
Claim 8
Dependent Claim
87 words
A four-wheel steering vehicle in accordance with claim 1 wherein. the steering ratio property is set to provide a steering ratio of a reverse phase in which the rear wheels are steered in a direction opposite to that of the front wheels steered when the vehicle is in a relatively low speed and to provide a steering ratio of a same phase in which the rear wheels are steered in the same direction as the front wheels steered when the vehicle is in a relatively high speed.
Claim 9
Dependent Claim
19 words
A four-wheel steering vehicle in accordance with claim 7 wherein the steering ratio property is changed by motor means.
Claim 10
Dependent Claim
42 words
A four-wheel steering vehicle in accordance with claim 8 wherein the compensating means provides the motor means with a relatively low speed in an abnormal condition of the anti-lock braking system in comparison with a normal condition of the anti-lock braking system.
Claim 11
Dependent Claim
29 words
A four-wheel steering vehicle in accordance with claim 7 wherein the compensating means maintains the rear wheels at neutral positions in an abnormal condition of the anti-lock braking system.
Claim 12
Dependent Claim
33 words
A four-wheel steering vehicle in accordance with claim 7 in which the compensating means maintains the steering ratio at a value just before an abnormal condition of the anti-lock braking system is detected.
Claim 13
Dependent Claim
35 words
A four-wheel steering vehicle in accordance with claim 7 in which the compensating means shifts the steering ratio property in a direction of the same phase in an abnormal condition of the anti-lock braking system.
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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) | 1992-06-19 | 1992-12-19 | 1993-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-19 | 1996-12-19 | 1997-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-19 | 2000-12-19 | 2001-06-20 | $7700.00 | Window Closed / Lapsed |