The
V-belt length is defined in different
ways in the standards but it is measured
according to specified methods in
all cases. The measuring machine consists
of two pulleys with the same datum-diameter,
effective-diameter or two plane pulleys.
The measurement load on the moving
pulley depends on the belt section.
Datum
belt length Ld [mm]
is measured over pulleys with datum-diameter
dd [mm]
Ld = 2 x e +dd x p [mm]
The ISO term datum length Ld [mm] is
identical
with the previously used pitch belt
length Lp [mm]
Effective
belt length Le [mm]
The effective-diameter of the pulleys,
de [mm] is
used for calculating the belt length.
Le = 2 x e + de x p [mm]
Outside
belt length La [mm]
The physical outside length of the V-belt
is measured
with a measuring tape on the outside
of the belt
while the belt is installed in the measuring
machine.
Inside
belt length Li [mm]
is measured over two plane pulleys with
the diame-
ter d[mm], centre distance e [mm], is
calculated as
follow:
Li = 2 x e + d x p [mm]
Mean
belt length Lm [mm]
occurs in connection with double V-belts,
and for all
practical purpose it may be said to
be » effective
belt length.
Lm » Le [mm]
V-BELT IN PULLEY
GROOVE
The placement of
a V-belt section in the groove of
the standard pulley designed for it
is described with the term Ride. This
is the distance from the top of the
section to the outside diameter dd
of the pulley.
The permissible maximum/ minimum
distance/ride is specified in standards.
RIDE
OUT
Distance [1] from the top of the V-belt
section to the outside diameter de
of the pulley.
RIDE
O/RIDE FLUSH
The top of the V-belt section is flush
with the outside diameter de of the
pulley.
RIDE
IN
Distance [2] from the top of the V-belt
section
to the outside diameter de of the
pulley..
A change in ride indicates uneven belt
wear or worn sheaves. Change belt
sheaves with new set.
RIDE
OUT
RIDE
O/RIDE FLUSH
RIDE
IN