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In the development of the S Matic system, Honda set the following
three goals.
| (1) |
Compact and light weight |
| (2) |
Shift characteristics that allow attainment of fuel
economy, exhaust emissions, quietness and driving performance. |
| (3) |
The control system shall not be complex. |
In the system applied to the 2004 FORZA, the manual mode has
been added to the two kinds of automatic modes. From the standpoint
of providing additional riding fun rather than purly the pursuit
of efficiency, the system permits the rider’s active choice
of shifting in 6 speeds.
While the unsprung, unit-swing engine configuration is common
in scooters, as the engine weight is very influential to the
dynamic performance of the vehicle, the unit has to be as light
as possible. To maintain the virtue of the conventional belt-type
CVT, as well as employing the rubber belt, the pulleys are made
of die-cast aluminum alloy.
The boss of the movable drive face is made of steel and cast
in the aluminum alloy pulley to reduce the pitch diameter to
allow for a wide-range reduction ratio.
 Honda S Matic system overview
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Outlines of system
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The sensors are incorporated to detect the drive pulley
revolutions, the driven pulley revolutions, the pulley
position, the vehicle speed, and the throttle opening.
Referring to the inputs from those sensors and switches,
the reduction ratio control unit determines items to control,
and controls the pulley position by controlling the drive
motor. |
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The control current occurs in the motor, the motor spins,
and the rotation is transmitted to the movable gear via
the reduction gear. The feed thread in the movable gear
changes the rotating force into an axial force that moves
the movable drive face for shifting of the reduction ratio.
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The guide key is employed to allow the movable drive
face to slide and transmit the engine torque. As the gears
in the shifting mechanism are of no lubrication type,
some gears are made of plastic to reduce wear and weight.
The guide key, which transmits torque, and a part of the
feed thread are grease-lubricated to ensure smooth operations. |
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In addition to the above-mentioned, the outside air
is introduced in the belt housing to lower the belt temperature
and extend belt life. Also, careful measures are taken
to prevent dust entry into the housing. Although the construction
in the driven side is similar to that of a conventional
belt-type CVT, the rotor has been added to detect the
pulley revolutions. |
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