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 throught 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 identicalto the ordinary manual steering.
Furthermore,
the force from the backward direction (force pressing the steering rack) is converted into the rota-
tion torque of the screw shaft, instantaneous kick-back from road surface will rapidly rotate the motor. In such a rapid
rotation, 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 assist force.
BALL SCREW
NUT
BALL
Summary of Contents for Acura NSX 1991
Page 1: ... j s _ _ ...
Page 3: ......
Page 22: ...Special Tools Individual tool lists are located at the front of each section ...
Page 23: ...Specifications Standards and Service Limits 3 2 Design Specifications 3 l 1 ...
Page 39: ...Body Specifications m I 1 175 46 3 Unit mm in ...
Page 40: ...Maintenance Lubrication Points 4 2 Maintenance Schedule 4 4 ...
Page 42: ... 13 I 0 4 3 ...
Page 60: ...Engine Removal Installation ...
Page 81: ...lr I 6 7 ...
Page 191: ... n EilEli3 A A A Cl51 c4 BLU 1 TACHO METER CONNECTOR Cl61 C478 C488 REDlYEL YELlRED J A GlOl ...
Page 193: ... PGM FI 1 IDLE CONTROL 1 FUEL SUPPLY 1 EMISSION CONTROL II 17 ...
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Page 211: ...I I 35 ...
Page 219: ... cont d II 43 ...
Page 235: ...1 l 59 ...
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Page 285: ...1 l 109 ...
Page 434: ...t 14 46 ...
Page 477: ...14 95 ...
Page 482: ...Illustrated Index L Side Cover 14 100 ...
Page 484: ...Illustrated Index Transmission Housing 14 102 ...
Page 486: ...Illustrated Index Torque Converter Housing Valve Body ...
Page 527: ...3 Assemble the transmission in the following numbered sequence Replace cont dl ...
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Page 698: ...9 Nom 0 9 kg m 7 lb ft REAR 9 Nom 0 9 kg m 7 lb ft ...
Page 724: ...19 37 ...
Page 766: ...19 79 ...
Page 888: ...Frame Repair Chart 20 62 ...
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Page 950: ...Blower 22 62 ...
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Page 1003: ... JND WIRE EN NE GROUND WIRE B ...
Page 1005: ... lzl A ENGINE W I R E H A R N E S S cont d 23 l 9 ...
Page 1007: ... rl p173 5 Cl34 Cl32 Ti03 23 21 ...
Page 1009: ...C2bl c262 I C203 cont d 23 23 ...
Page 1011: ... rl SUB RELAY BOX A cont d 23 25 ...
Page 1013: ...FRONT COMPAR 23 27 J ...
Page 1015: ...e RIGHT RETRACTOR SUB HARNESS I LEFT RETRACTOR SUB HARNESS I ...
Page 1019: ...C466 C465 C468 C464 c473 FLOOR WlFiE HARNESS co d 23 33 ...
Page 1021: ... ITI RETRACTABLE HEADLIGHT CONTROL UNIT i FLOOR WIRE HARNESS 23 35 ...
Page 1023: ...MAIN FUSE BOX I 23 37 ...
Page 1027: ...DRIVER S DOOR WIRE HARNESS PASSENGER S DOOR WIRE 23 41 ...
Page 1029: ...SRS CONTROL UN FUEL TANK WIRES 23 43 ...
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Page 1275: ...1 ACTUATOR ASSEMBLY SPEED SENSOR 23 l 33 ...
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