EP0249902A2
Expired / Lapsed
EP
⏱️ 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: —
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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 (13) for subsidiarily energizing said steering apparatus; a handle for generating a steering torque; a torque sensor (3) for producing a signal corresponding to said steering torque which includes a potentiometer (31) having a movable electrode for detecting a torsional angle relating to said steering torque, and a torque neutral region sensor (32) arranged to operate together with said movable electrode to produce a signal indicating whether said steering torque is within said torque neutral region; a motor current detection circuit (94) for detecting a current flowing in said DC motor (13); an electromagnetic clutch (16) for coupling/decoupling an output of said DC motor (13) to/from said steering apparatus; a power supply circuit (11, 108) for suppplying electric power to said DC motor (13) and said electromagnetic clutch; and a fail safe relay (91) being interrupted to remove said subsidiary steering force when a current exceeding that relating to said torque neutral region flows in said motor-current detection circuit (94) while said steering torque is within said torque neutral region.
Inventors
- 👤 Mitsuharu Mitsubishi Denki Morishita
- 👤 Shinichi Mitsubishi Denki Kohge
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 21:16
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
191 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 current exceeding that corresponding to 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
191 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 current exceeding that corresponding to 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
213 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 relating to said steering torgue and a torgue 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 current exceeding that corresponding to 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
213 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 relating to said steering torgue and a torgue 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 current exceeding that corresponding to 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)
No citation records indexed.
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