§
Luxuse
Patent Intelligence
Sign In
← Back to Patent Explorer
EP0285177A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Power steering system incorporating electric motor

Assignee: Koyo Seiko Co Ltd
•
Filing: 1988-03-31
•
Granted: —
•
Expires: 2008-03-31
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A power steering system having an electric motor (18) and including an input shaft (10) fixed to a steering wheel (15), an output shaft (11) coupled to the motor (18) via a reduction gear (17), and a torsion bar (12) provided between the input and output shafts (10, 11), the output shaft (11) being rotatable by the resultant of a manual torque for rotating the wheel (15) and the torque of the motor (18). The system comprises a sensor (20) for detecting the relative angular displacement between the input shaft (10) and the output shaft (11), and a microcomputer (28) having stored therein the relationship between the relative angular displacement and the motor current target value for determining the direction of rotation of the motor (28) and a motor current target value from the output of the sensor (20) to produce outputs. The relationship stored in the microcomputer (20) is a nonlinear re­lationship wherein variations in the motor current target value with the relative angular displacement are small in the range of small relative angular displace­ments but are great in the range of great displacements.

Inventors

  • 👤 Toshihiko Daido
  • 👤 Mitsugu Fujiwara
  • 👤 Shigeo Nishimura

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-05 20:22
CPC Classifications
B; B62; B62D; B62D5/00; B62D5/04; B62D5/0457; B62D5/046; B62D5/0463

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 197 words
A power steering system having an electric motor (18) incorporated therein and including an input shaft (10) fixed to a steering wheel (15), an output shaft (11) coupled to the motor (18) via a reduction gear (17), and a torsion bar (12) provided between the input and output shafts (10, 11), the output shaft (11) being rotatable by the resultant of a torque for the person to rotate the steering wheel (15) and the torque of the motor (18), the system being characterized in that it comprises: a sensor (20) for detecting the relative angular dis­placement between the input shaft (10) and the output shaft (11), and a microcomputer (28) having stored therein the relationship between the relative angular displacement and the motor current target value for determining the direction of rotation of the motor (18) and a motor current target value from the output of the sensor (20) to produce outputs, the relationship stored in the microcomputer (28) being a nonlinear relationship wherein variations in the motor current target value with the relative angular displacement are small in the range of small relative angular displacements bur are great in the range of great relative angular displace­ments.
Claim 2
Dependent Claim 197 words
A power steering system having an electric motor (18) incorporated therein and including an input shaft (10) fixed to a steering wheel (15), an output shaft (11) coupled to the motor (18) via a reduction gear (17), and a torsion bar (12) provided between the input and output shafts (10, 11), the output shaft (11) being rotatable by the resultant of a torque for the person to rotate the steering wheel (15) and the torque of the motor (18), the system being characterized in that it comprises: a sensor (20) for detecting the relative angular dis­placement between the input shaft (10) and the output shaft (11), and a microcomputer (28) having stored therein the relationship between the relative angular displacement and the motor current target value for determining the direction of rotation of the motor (18) and a motor current target value from the output of the sensor (20) to produce outputs, the relationship stored in the microcomputer (28) being a nonlinear relationship wherein variations in the motor current target value with the relative angular displacement are small in the range of small relative angular displacements bur are great in the range of great relative angular displace­ments.
Claim 3
Dependent Claim 70 words
A system as defined in claim 1 wherein the microcomputer (28) has an operating time interval of up to 2 milliseconds from the detection of an input from the sensor (20) until the detection of another input therefrom following the production of the motor current target value, and an operating time interval of up to 500 microseconds from the detection of the input until the production of the target value.

References Cited (Backward Citations)

No citation records indexed.

USPTO Annuity & Maintenance Windows

Maintenance schedule is calculated for granted US utility patents.

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag