US4785901A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rack and pinion steering gear with electric power assistance
Assignee: Tokai TRW and Co Ltd
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Filing: 1987-07-08
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Granted: 1988-11-22
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Expires: 2007-07-08
Abstract
Abstract A rack-pinion type electrically powered steering apparatus is provided with an electronic control circuit adapted to control a motor driving current which is applied to a motor for power assistance, in response to a steering load characteristic and/or a vehicle speed characteristic. The steering apparatus is also provided with a rack end proximity sensor adapted to detect a position adjacent the both ends of the rack during a steering operation, and a device for providing the motor driving current with an attenuation characteristic in response to the detected signal from said rack end proximity sensor.
Inventors
- 👤 Naoyuki Maeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:03
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/04; B62D5/0457; B62D5/046; B62D5/0469
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
164 words
A rack and pinion steering gear with electric power assistance comprising an electronic control circuit adapted to control a motor driving current which is applied to a motor for power assistance in response to a steering load characteristic and/or a vehicle speed characteristic, characterized by provision of a rack end proximity sensor adapted to detect a position adjacent both ends of the rack during a steering operation, and means for providing said motor driving current with an attenuation characteristic in response to a detected signal from said rack end proximity sensor, said means for providing an attenuation characteristic comprising a rack end signal processing circuit, a time constant circuit, and a current attenuation control circuit adapted to attenuate said motor driving current to a predetermined level, said time constant circuit providing when the detected signal from said rack end proximity sensor activates said rack end processing circuit a time-delayed characteristic to the motor driving current which is attenuated by said current attenuation control circuit.
Claim 2
Dependent Claim
164 words
A rack and pinion steering gear with electric power assistance comprising an electronic control circuit adapted to control a motor driving current which is applied to a motor for power assistance in response to a steering load characteristic and/or a vehicle speed characteristic, characterized by provision of a rack end proximity sensor adapted to detect a position adjacent both ends of the rack during a steering operation, and means for providing said motor driving current with an attenuation characteristic in response to a detected signal from said rack end proximity sensor, said means for providing an attenuation characteristic comprising a rack end signal processing circuit, a time constant circuit, and a current attenuation control circuit adapted to attenuate said motor driving current to a predetermined level, said time constant circuit providing when the detected signal from said rack end proximity sensor activates said rack end processing circuit a time-delayed characteristic to the motor driving current which is attenuated by said current attenuation control circuit.
Claim 3
Dependent Claim
168 words
In a rack and pinion steering gear having an electric motor for power assistance: a rack end proximity sensor to detect respective end portions of the rack when the rack approaches an end of its movement during a steering operation; and an electronic control circuit for controlling a motor driving current which is applied to the motor for effecting power assistance in response to a steering load characteristic and/or a vehicle speed characteristic, said electronic control circuit comprising: a current attenuation control circuit for attenuating the motor driving current to a predetermined level when the rack approaches an end of its movement during a steering operation; a rack end signal processing circuit activated in response to said proximity end sensor detecting a respective end portion of the rack; and a time constant circuit for applying a control signal to said current attenuation control circuit in response to said rack end signal processing circuit being activated to cause said current attenuation to occur over a predetermined amount of time.
Claim 4
Dependent Claim
168 words
In a rack and pinion steering gear having an electric motor for power assistance: a rack end proximity sensor to detect respective end portions of the rack when the rack approaches an end of its movement during a steering operation; and an electronic control circuit for controlling a motor driving current which is applied to the motor for effecting power assistance in response to a steering load characteristic and/or a vehicle speed characteristic, said electronic control circuit comprising: a current attenuation control circuit for attenuating the motor driving current to a predetermined level when the rack approaches an end of its movement during a steering operation; a rack end signal processing circuit activated in response to said proximity end sensor detecting a respective end portion of the rack; and a time constant circuit for applying a control signal to said current attenuation control circuit in response to said rack end signal processing circuit being activated to cause said current attenuation to occur over a predetermined amount of time.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-11-22 | 1992-05-23 | 1992-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-22 | 1996-05-23 | 1996-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-22 | 2000-05-23 | 2000-11-22 | $7700.00 | Window Closed / Lapsed |