Spring Drive Mechanism
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Here is the step-by-step description of the Spring Drive in
an easy-to-understand manner.
This is how the Spring Drive works.
1
Mainspring
The mainspring is wound by rotation of the oscillating
weight (or by turning of the crown), and its unwinding
power is the sole power source.
2
Gear train • hands
The unwinding power of the mainspring is transmitted via
the gear train to move the hands. No motor or battery is
mounted.
3
Tri-synchro regulator
The unwinding power of the mainspring also rotates the
glide wheel. This generates small electricity in the coil to
drive the IC and crystal oscillator. At the same time, an
electric magnetic field is generated on the glide wheel.
The IC detects the spinning speed of the glide wheel
based on the accuracy of the electric signals of the crystal
oscillator, and adjusts the spinning speed of the glide
wheel while applying and releasing the electromagnetic
brake.
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Differences between the Spring Drive and
mechanical watch
For the Spring Drive, the mainspring is wound and
the unwinding power of the mainspring moves the
hands in the same manner as the mechanical watch.
It differs from the mechanical watch only in the
speed-regulating unit (mechanism for controlling
accuracy).
◎
Temperature change
Accuracy of mechanical watches depends on a balance spring attached to a part called the
balance. This part has properties for expanding and contracting with temperature changes, and
influences the accuracy of a watch. Accuracy of the Spring Drive is never largely influenced by
temperature changes like that of mechanical watches since the crystal oscillator controls it.
(Note) Accuracy of the Spring Drive
Average monthly rate of ±10 seconds or ±15 seconds is the accuracy of a watch when
it is worn on a wrist at a temperature range between 5°C and 35°C.
◎
Difference in position
For mechanical watches, the accuracy is influenced even by a difference in position or direction
of a watch. This is also caused by the balance that controls the accuracy of mechanical watches.
Due to the difference in position, the area where the shaft of the balance contacts with other
parts differs, and such differences in resistance influence the accuracy. As the Spring Drive
adopts a crystal oscillator not a balance, the accuracy is not influenced by a difference in
position.
◎
Impact
Mechanical watches are susceptible to impacts. If a mechanical watch was subject to impact,
amplitude of vibration of the balance (angle for which the balance rotates right and left) is
changed, and even the form of the balance spring is changed. In this regard, the Spring Drive
is superior to mechanical watches in impact resistance because it adopts a crystal oscillator
not a balance.
◎
Overhaul
Parts that become worn or severely damaged are the balance, pallet fork, and escape wheel
& pinion which are collectively called the speed-regulating unit or escapement. These parts
“come into contact or collide” mutually and control unwinding of the mainspring.
For the Spring Drive, wear and damage occur less than mechanical watches since the spinning
speed of the glide wheel is adjusted by a “contact-free” electromagnetic brake. However, as
the structure of gear train is the same as mechanical watches, abrasion powder may be
generated by contact of the wheels & pinions. An overhaul is recommend every three to four
years.
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English
