Patent US5225753A successfully refreshed from Google Patents.
US5225753A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric control apparatus for four-wheel steering system
Assignee: Toyota Motor Corp
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Filing: 1991-07-29
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Granted: 1993-07-06
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Expires: 2011-07-29
Abstract
Abstract In an electric control apparatus for a four-wheel steering system including an electric motor the rotary angle of which is electrically controlled in accordance with a target steering angle of rear road wheels, and a hydro-mechanical tracer mechanism having a fluid control valve the valve element of which is drivingly connected to the electric motor to be displaced in proportion to the rotary angle of the electric motor, the tracer mechanism being arranged to steer the rear road wheels in proportion to a displacement amount of the valve element, the target steering angle is converted into a control value for rotation of the electric motor, and a drive signal indicative of the control value is applied to the electric motor. The electric control apparatus is designed to greatly change the control value to and from zero when the target steering angle is less than a predetermined small angle and to change the control value in proportion to the target steering angle when the target steering angle is more than the predetermined small angle.
Inventors
- 👤 Shin Koike
- 👤 Osamu Takeda
- 👤 Hiroaki Tanaka
- 👤 Mizuho Sugiyama
- 👤 Kaoru Ohashi
- 👤 Hitoshi Iwata
- 👤 Masaru Ishikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:39
CPC Classifications
B; B62; B62D; B62D7/00; B62D7/06; B62D7/14; B62D7/15; B62D7/1581; B62D7/159
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
221 words
An electric control apparatus for a four-wheel steering system in an automative vehicle having a set of dirigible front road wheels and a set of dirigible rear road wheels, comprising: calculation means for calculating a target steering angle of the rear road wheels; an electric motor the rotary angle of which is electrically controlled in accordance with the target steering angle; a hydro-mechanical tracer mechanism including a fluid control valve the valve element of which is drivingly connected to said electric motor to be displaced in proportion to the rotary angle of said electric motor, said tracer mechanism being arranged to steer the rear road wheels in proportion to a displacement amount of said valve element; conversion means for converting the target steering angle into a control value for rotation of said electric motor; and means for applying a drive signal indicative of the control value to said electric motor for controlling the rotary angle of said electric motor; wherein the electric control apparatus further comprises means for greatly changing the control value to and from zero in accordance with the target steering angle when the target steering angle is less than a predetermined small angle and for changing the control value in proportion to the target steering angle when the target steering angle is more than the predetermined small angle.
Claim 2
Dependent Claim
221 words
An electric control apparatus for a four-wheel steering system in an automative vehicle having a set of dirigible front road wheels and a set of dirigible rear road wheels, comprising: calculation means for calculating a target steering angle of the rear road wheels; an electric motor the rotary angle of which is electrically controlled in accordance with the target steering angle; a hydro-mechanical tracer mechanism including a fluid control valve the valve element of which is drivingly connected to said electric motor to be displaced in proportion to the rotary angle of said electric motor, said tracer mechanism being arranged to steer the rear road wheels in proportion to a displacement amount of said valve element; conversion means for converting the target steering angle into a control value for rotation of said electric motor; and means for applying a drive signal indicative of the control value to said electric motor for controlling the rotary angle of said electric motor; wherein the electric control apparatus further comprises means for greatly changing the control value to and from zero in accordance with the target steering angle when the target steering angle is less than a predetermined small angle and for changing the control value in proportion to the target steering angle when the target steering angle is more than the predetermined small angle.
Claim 3
Dependent Claim
107 words
An electric control apparatus for a four-wheel steering system as claimed in claim 1, wherein an electric step motor is adapted as said electric motor, and wherein the electric control apparatus further comprises means for controlling a periodic time for applying a drive pulse indicative of the control value to said step motor to a first predetermined short period of time when the target steering angle is less than the predetermined small angle and for controlling the periodic time to a second predetermined period of time longer than the first predetermined short period of time when the target steering angle is more than the predetermined small angle.
Claim 4
Dependent Claim
81 words
An electric control apparatus for a four-wheel steering system as claimed in claim 1, wherein an electric step motor is adapted as said electric motor, and said hydro-mechanical tracer mechanism includes a spool valve the valve spool of which is drivingly connected to said step motor to be axially displaced in proportion to the rotary angle of said step motor, said tracer mechanism being arranged to steer the rear road wheels in proportion to an axial displacement of said valve spool.
References Cited (Backward Citations)
US4657102A
Cited
JPS5981263A
Cited
JPS5981257A
Cited
US4471278A
Cited
US4732231A
Cited
JPS62113651A
Cited
US4828283A
Cited
US4715466A
Cited
JPS62120276A
Cited
US4874054A
Cited
EP0280207A2
Cited
DE3814059A1
Cited
US4852897A
Cited
JPS6462165A
Cited
JPS6462163A
Cited
JPS6462162A
Cited
EP0312096A2
Cited
US4951198A
Cited
EP0316932A2
Cited
US4998201A
Cited
US5086859A
Cited
US4972916A
Cited
EP0404422A2
Cited
US5076382A
Cited
US5048629A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-07-05 | 1997-01-04 | 1997-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-05 | 2001-01-04 | 2001-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-05 | 2005-01-04 | 2005-07-06 | $7700.00 | Window Closed / Lapsed |