Honda G100K2 Applications Manual page 33

VIBRATION
VIBRATION ISOLATING TECHNIQUES
Rigid mount engine bed
In case the engine is mounted on a solid frame or engine base following point should be considered.
the dimensions (length and width) of the engine base / frame should be as small as possible to avoid vibration
-
amplification
- the thickness of the engine bed should be kept to a minimum of 6 mm to avoid bending by weight or belt
tension.
- If increased engine bed thickness is not possible, reinforcements should be added to increase rigidity.
Flatness of the engine bed should be kept to a maximum to avoid stress tightening.
-
Common engine bed with rubber insulator
In case the engine and application are mounted on a common bed or frame supported by rubber insulators, the
insulators absorb the vibrations and transmit these to the sub-frame.
Incorrectly chosen rubber insulators may generate rocking motions of the engine bed and high resonance vibration.
The location and the hardness of the rubber
insulators is important; the static deflection of
each rubber mount should be equal.
On a machine with non-uniform weight distribution,
mountings nearer to the center of gravity must be
stiffer than those more remote from it.
The most efficient isolation is obtained if the rubber
mountings are fixed so that their individual distance
to the engine bed's center of gravity is equal.
A longer span length gives less vibration and moves the
resonant frequency to another level.
If an application spends a significant amount of time
at resonance, e.g. because of frequent stop, start or
acceleration, rubber mountings should be adapted
to avoid these resonance points.
Gravity point
RUBBER HARDNESS –SHORE or IRHD
Rubber hardness is measured by comparing
the difference of depth of indentation
between the small initial force and the much
larger final force applied by a standard size
and shape impacting gauge.
Shore A rubber hardness and ISO's IRHD
use a similar hardness scale from 0 to 100
(soft to hard).
Shore D rubber hardness scale, ranging
from 0 to 100 uses a needle point impacting
gauge and is used for harder rubbers.
For example: standard car tyre hardness
shore A - 65 and shore D - 20.
Equal distance
Stiffer
- 32 -
Less stiff