TOHATSU MD 30B2 Service Manual page 5

This manual uses SI unit system (International System of Units) for the pressure, force (load), torque and
stress. This manual newly adopts the international unit construction system (SI unit system) followed by the
conventional imperial and metric systems enclosed by ( ) and [ ] as described below.
Example : <Pressure>
0.90 MPa (128 psi) [9.0 kgf/cm
* Measurements are shown using SI unit followed by conventional units (US unit) and [Japanese domestic unit].
Example : <Driving torque>
18 N·m（13lb·ft）[1.8 kgf·m]
* The conventional unit for measurement of force uses "kgf (kilogram force)" to discriminate it from
"kg (mass kilogram)" of SI unit system.
Example : <Volume>
（30.4 fl.oz）
3
900 cm
Example : <Length>
10 mm（0.39 in）
<Reference>
What is the SI unit system?
Although the measurement unit is standardized mostly with metric system in the world, the metric system
includes different kinds of unit systems.
Though the metric system was established expecting that a single unit system is used in the world, various
physical units were established later, resulting in branching the metric system in different unit systems.
The new unit system is called "International System of Units" because it was established for the purpose of
unifying the different unit systems.
Since the metric system was initially established in France, and International Bureau of Weights and
Measures (IBWM) is located in Paris, General Conference of Weights and Measures (GCWM) passes a
resolution of the international unit system as "Systéme International d'Unités (French)" that is abbreviated as
"SI unit".
For example, conventional metric system uses the unit of mass (kg) and unit of force (kg or kgf) without
discriminating them, but the SI unit system uses, for example, "kg" as the unit of mass, and "N" as the unit of
force, aiming to apply a kind of unit for a kind of physical quantity.
TLD D30/40/50B2 2013
2
]
Conventional system (kilo-gram meter unit)
Conventional system (US pound inch unit)
SI unit (1 kgf/cm2 = 0.0980665 MPa)
*
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