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Details
of Hondamatic mechanism
An
ordinary hydraulic transmission for industrial machinery is
not appropriate for motor vehicles from the viewpoint of transmission
efficiency. In Hondamatic, the efficiency is enhanced by splitting
the input power into hydraulic and mechanical components. Especially,
to prevent leakage of high pressure fluid, which directly affects
transmission efficiency, the unique distributor valve is employed.
The automatic mode for infinitely variable automatic control
of reduction ratio and the ESP mode allowing rider’s choice
from 5 speeds are provided, and allow changes of reduction ratio
without any shifting shock. |
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Infinitely-variable
reduction ratio by means of variable-angle swash plate |
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The reduction ratio of Hondamatic depends on
the pump-to-motor volume ratio. The angle of pump swash plate
driven by engine power is constant all the time, and the seven
hydraulic pump pistons produce a hydraulic pressure depending
on engine power output. The electronically-controlled DC motor
changes the angle of the motor-side swash plate via the gears
and the ball thread, thus changing the motor cylinder volume
without a step, which changes the reduction ratio continuously.
Because of the above-mentioned working principles, the reduction
ratio becomes maximum when the motor-side swash plate angle
is at the maximum, and when the angle is minimum (vertical to
the axis), there is no reciprocation of motor-side pistons,
which causes a direct coupling with a theoretical reduction
ratio of 1:1. |
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Pistons
for hydraulic pump/motor and dimple plate |
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The dimple plates having spherical dimples corresponding
1 to 1 to the pistons are located between the hydraulic pump
side and hydraulic motor side pistons and the swash plate. The
dimple plate relieves stresses in the contact area and improves
durability.
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Distributor
valve |
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The shifting of the high pressure
fluid passage and the low pressure fluid passage in the piston
chamber and the cylinder in each the pump and the motor is
performed by the spool-type distributor valve paired with
the piston and laid radial. The distributor valve is driven
by the eccentric ring synchronized with the swash plate, and
synchronized with the movement of each piston. The eccentric
ring off-centered from the rotation center of the cylinder
spins, the distributor valve repeats radial reciprocation
against the cylinder, and shifts the high pressure fluid passage
and the low pressure fluid passage in accordance with each
out-going and in-coming strokes of the piston.
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