US4736810A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fail safe method and system for motor driven power steering apparatus
Assignee: Mitsubishi Electric Corp
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Filing: 1987-06-12
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Granted: 1988-04-12
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Expires: 2007-06-12
Abstract
Abstract A fail safe system for a motor driven power steering apparatus comprises a DC motor for subsidiarily energized said steering apparatus; a handle for receiving steering rotary force to produce a corresponding steering torque; a torque sensor for producing a signal corresponding to said rotary force applied to said handle, said torque sensor comprising a potentiometer having a movable electrode for detecting a torsional angle owing to said steering torque and a torque neutral region sensor arranged to operate together with said movable electrode for detecting a neutral region of said steering torque to produce a signal indicating whether said steering torque is within said torque neutral region or not; a motor current detection circuit for detecting a current flowing in said DC motor; an electromagnetic clutch for coupling/decoupling an output of said DC motor to/from said steering apparatus; a power supply circuit for supplying electric power to said DC motor and said electromagnetic clutch; and a fail safe relay provided with a normally opened contact connected in series in said power supply circuit; said fail safe relay being interrupted to remove said subsidiary steering force when a larger current exceeding said torque neutral region flows in said motor-current detection circuit while said torque neutral region sensor produces the signal indicating that said steering torque is within said torque neutral region.
Inventors
- 👤 Mitsuharu Morishita
- 👤 Shinichi Kohge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:53
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/06; B62D5/04; B62D5/0457; B62D5/0481; B62D5/0487
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
189 words
A fail safe method for a motor driven power steering apparatus, comprising the steps of: turning on a key switch for supplying electric power from a battery to a control unit and a steering torque sensor; detecting a steering torque corresponding to a rotary force applied to a handle by a potentiometer of said steering torque sensor, and detecting by a torque neutral region sensor of said steering torque sensor whether or not said steering torque is within a neutral region; supplying electric power from a battery to a DC motor for supplying a subsidiary steering force to said steering apparatus in response to signals generated from said potentiometer and said torque neutral region sensor; detecting a current flowing in a DC motor by a motor current detection means; and interrupting a fail safe relay provided with a normally opened contact connected between said battery and said DC motor to thereby remove said subsidiary steering force, if a larger current exceeding said torque neutral region flows in said DC motor current detection means while said torque neutral region sensor detects that said steering torque is within a neutral region.
Claim 2
Dependent Claim
189 words
A fail safe method for a motor driven power steering apparatus, comprising the steps of: turning on a key switch for supplying electric power from a battery to a control unit and a steering torque sensor; detecting a steering torque corresponding to a rotary force applied to a handle by a potentiometer of said steering torque sensor, and detecting by a torque neutral region sensor of said steering torque sensor whether or not said steering torque is within a neutral region; supplying electric power from a battery to a DC motor for supplying a subsidiary steering force to said steering apparatus in response to signals generated from said potentiometer and said torque neutral region sensor; detecting a current flowing in a DC motor by a motor current detection means; and interrupting a fail safe relay provided with a normally opened contact connected between said battery and said DC motor to thereby remove said subsidiary steering force, if a larger current exceeding said torque neutral region flows in said DC motor current detection means while said torque neutral region sensor detects that said steering torque is within a neutral region.
Claim 3
Dependent Claim
24 words
A fail safe method as claimed in claim 1, wherein said torque neutral region sensor operates together with a movable electrode of said potentiometer.
Claim 4
Dependent Claim
211 words
A fail safe system for a motor driven power steering apparatus, comprising: a handle receiving steering rotary force to procude a corresponding steering torque; a torque sensor for producing a signal corresponding to said rotary force applied to said handle, said torque sensor comprising a potentiometer having a movable electrode for detecting a torsional angle owing to said steering torque and a torque neutral region sensor arranged to operate together with said movable electrode for detecting a neutral region of said steering torque to produce a signal indicating whether said steering torque is within said torque neutral region or not; a motor current detection circuit for detecting a current flowing in said DC motor; an electromagnetic clutch for coupling/decoupling an output of said DC motor to/from said steering apparatus; a power supply circuit for supplying electric power to said DC motor and said electromagnetic clutch; and a fail safe relay provided with a normally opened contact connected in series in said power supply circuit, said fail safe relay being interrupted to remove said subsidiary steering force when a larger current exceeding said torque neutral region flows in said motor-current detection circuit while said torque neutral region sensor produces the signal indicating that said steering torque is within said torque neutral region.
Claim 5
Dependent Claim
211 words
A fail safe system for a motor driven power steering apparatus, comprising: a handle receiving steering rotary force to procude a corresponding steering torque; a torque sensor for producing a signal corresponding to said rotary force applied to said handle, said torque sensor comprising a potentiometer having a movable electrode for detecting a torsional angle owing to said steering torque and a torque neutral region sensor arranged to operate together with said movable electrode for detecting a neutral region of said steering torque to produce a signal indicating whether said steering torque is within said torque neutral region or not; a motor current detection circuit for detecting a current flowing in said DC motor; an electromagnetic clutch for coupling/decoupling an output of said DC motor to/from said steering apparatus; a power supply circuit for supplying electric power to said DC motor and said electromagnetic clutch; and a fail safe relay provided with a normally opened contact connected in series in said power supply circuit, said fail safe relay being interrupted to remove said subsidiary steering force when a larger current exceeding said torque neutral region flows in said motor-current detection circuit while said torque neutral region sensor produces the signal indicating that said steering torque is within said torque neutral region.
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) | 1991-04-12 | 1991-10-12 | 1992-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-12 | 1995-10-12 | 1996-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-12 | 1999-10-12 | 2000-04-12 | $7700.00 | Window Closed / Lapsed |