SERVODIRECTION ELECTRIQUE POUR UN VEHICULE AUTOMOBILE

• Main Author: MIKIO SUZUKI, SHIGEO IWASHITA ET MASAAKI HAYASHI
• Format: Patent
• Language: French
• Published: 03.10.1986
• Edition: 4
• Subjects: LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS; MOTOR VEHICLES; PERFORMING OPERATIONS; TRAILERS; TRANSPORTING

A L'ARBRE DE DIRECTION 10 EST ACCOUPLE UN MOTEUR ELECTRIQUE 16 QUI FOURNIT UNE ENERGIE D'ASSISTANCE POUR ORIENTER LES ROUES DIRECTRICES 18 DU VEHICULE. L'ASSISTANCE DEPEND DE L'EFFORT MANUEL APPLIQUE AU VOLANT 11, DETECTE PAR UN CAPTEUR DE COUPLE 15 SUR L'ARBRE DE DIRECTION 10, AINSI QUE LA VITESSE DE MARCHE DU VEHICULE, DETECTEE PAR UN CAPTEUR DE VITESSE 26. DANS UNE PLAGE DE BASSE VITESSE, L'ASSISTANCE FOURNIE PAR LE MOTEUR ELECTRIQUE 16 AUGMENTE A MESURE QUE LA VITESSE DU VEHICULE DIMINUE. DANS UNE PLAGE DE GRANDE VITESSE, L'ASSISTANCE AUGMENTE PROPORTIONNELLEMENT A L'EFFORT APPLIQUE AU VOLANT 11. In an electric power steering device, an electric motor is drivingly connected to a steering shaft with a steering wheel for generating an assisting power to rotate the steering shaft. A memory has stored a control pattern which non-linearly varies an assisting power with variations in a steering effort. A microprocessor responsive to a vehicle speed detected by a speed sensor ascertains whether the detected vehicle speed is within a low speed range or within a high speed range. Ascertaining that the detected speed is within the low speed range, the microprocessor searches the memory for an assisting power corresponding to the steering effort detected by a torque sensor. Ascertaining that the detected vehicle speed is within the high speed range, on the other hand, the microprocessor calculates an assisting power based upon the detected steering effort and a constant. The microprocessor then outputs a control signal representing either of the searched and calculated assisting power to a signal modulator, which modulates the control signal based upon the vehicle speed from the speed sensor so that the assisting power generated by the electric motor is controlled to meet the modified signal from the signal modulator.