1991 ACURA NSX torque

AUX battery location 4WD air suspension glove box winter tyres

Page 1332 of 1640

ACURA NSX 1991 Service Repair Manual
Steering Gearbox

< Motor and Power Assist Mechanism >

A motor is housed inside the gearbox housing. It consists of a yoke with a permanent magnet fixed in it, a rotor with

a field coil, and brushe

Steering Gearbox

< Motor and Power Assist Mechanism >

A motor is housed inside the gearbox housing. It consists of a yoke with a permanent magnet fixed in it, a rotor with

a field coil, and brushes which pass electricity to rotor commutators. The motor is on the rack shaft of the steering gear-

box. The drive current from the power unit flows through the power relay and fail-safe relay to the brushes of the motor.

The drive current flows to rotor commutators through brushes, exciting the field coil of the rotor and rotates the rotor

with the magnetic action of the permanent magnet inside the yoke. The rotor rotates in the opposite direction when

the direction of drive current is reversed.

The rotation torque of the motor is transmitted to the ball screw throught the helical gear. The rotation torque on the

ball screw is converted into assist thrust in the direction of steering rack by the recirculating ball screw. The recirculating

ball screw acts to reduce the steering thrust put into the steering rack through the joint to lessen the steering force re-

quired at the steering wheel.

< Recirculating Ball Screw >

The recirculating ball screw is constructed so that balls roll between the screw shaft and the nut, and those coming out

of the screw face enter the screw groove again through a tube for recirculation. The rotation torque on the shaft is con-

verted into thrust in axial direction as the slope of the screw shaft presses against the nut through balls. Since the torque

conversion is made in this method through the screw shaft and balls, the friction is small, high transmission efficiency is

obtained for both the forward and backward directions, and the steering feels identical to the ordinary manual steering.

Furthermore, since the force from the backward direction (force pressing the steering rack) is converted into the rotation,

torque of the screw shaft, instantaneous kick-back from road surface will rapidly rotate the motor. In such a rapid rota-

tion, the inertia of the motor increases, which acts to reduce the kick-back. Any great kick-back will be transmitted from

the steering rack to the torque sensor on the pinion, which acts to twist the pinion shaft in the same direction as the input

direction of kick-back. As a result, the motor operates the kick-back to reduce asist force.

BALL SCREW
ROTOR

NUT

TUBE
STEEL BALL
HELICAL GEAR
BALL SCREW
RECIRCULATING

BALL SCREW
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