Three-Bolt Flange
Round in shape, these flanges are constructed as two-piece, pressed
steel housings, and are used in applications that require less critical
mounting accuracy and rigidity. The NTN nomenclature designation
for this unit is PF.
The bolt holes are spaced 120° apart, when using the center of
the shaft as the center reference point. This positioning of the
bolt holes requires a modification to the measurement of the distance
between bolt hole centers described previously.
Using the center of the shaft as the reference point, a circle
is drawn through the center point of all three holes. This dimension
is referred to as the diameter of the bolt hole center,
or the bolt pitch circle diameter.
The shaft size and the bolt pitch circle diameter for three-bolt
flanges are listed in the appropriate NTN catalog. Table
3 below provides a brief example of the dimensional
details available. In the section listed, the details are provided
for a three-bolt flange fitting a one-inch diameter shaft.
| Table 3: Three-bolt flanged housing variations—1"
diameter |
2-Bolt
flange
housing type |
Number
of
bolts |
Insert
bearing
series |
Bolt
center
distance (inch) |
Housing
material |
Application
duty |
PF
RPF |
3
3 |
2
2 |
2 63/64
3 35/64 |
Pressed Steel
Pressed Steel |
Light
Light |
|
