The Basic Concept
The main limiting factors in hydraulic transmissions are
low efficiency and low power capacity due to sliding friction between moving
parts and the heat they generate which increases exponentially with the
speed of rotation and the power transmitted.
The speed problem has been
in part overcome by means of hydrodynamic contact between sliding parts
which reduces friction at high speeds. However, this does not eliminate
the speed-limiting centrifugal forces generated by alternating masses
and the hydrodynamic bearing dissapears with reduced operating speeds.
In mechanical transmissions the problem of efficinecy is overcome mainly
with the use of roller bearings and mechanical balancing, but also with
advanced material and surface treatment technologies.
This new design is
born of a longstanding knowledge of both the mechanical and hydraulic
engineering technologies involved and manages to combine the advantages and
eliminate the disadvantages of both.
The efficiency and other operating
characteristics achieved are extremely interesting, for example:
The photograph on the cover page refers to a 50 cc variable displacement
motor, rated for operation at 250 bar, which achieves more than 95%
starting torque, is capable of reaching very high speeds and reaches a
minimum displacement of 5% before stalling.
This is possible due to the
drastic reduction in areas of sliding contact between moving parts and the
absence of heavy alternating masses.
This performance cannot be
equalled by any commercially available hydraulic motor or pump.