ITEM LRE 8 D10 80x40 ZU 40 R25, Notes On Use And Installation, Page: 29 / 36

11
Δ
L = L
􃃻 F
V
_______
1000 􃃻 K
The Proximity-Switch Fastening Set can be used to position and secure induc-
tive Proximity Switches for homing positions and electric terminal position lim-
its in the system groove of Timing-Belt Reverse Unit 8 40 R25. The Proximity
Switch fixings must be shortened as appropriate to the application scenario.
Positioning Proximity Switches
Similar to the picture
The necessary Timing-Belt tension must be determined and set in line with the
anticipated loads.

If the LRE 8 D14 ZU 40 R25 has been supplied fully preassembled, you
will need to check the pre-tensioning against the order specifications. After a
running-in time of 24 hrs, check the operating tension of the Timing Belt again
and adjust it if necessary.
When tensioning the Timing Belt, first identify the zero point at which the
untightened Belt has no sag at all and pre-tensioning begins. To do that, draw
the moving part of the Tensioning Block towards its fixed counterpart by alter-
nately tightening the tensioning screws. Calculate the necessary tensioning
adjustment or elongation of the Timing Belt according to the operating load of
the Linear Unit.
Conventional calculation:
Following applies: F
P
+ F
x
< F
Bperm
and: F
P
> F
x
Where: F
x
= m x a+ m x g +F
B
Where: ΔL = Tensioning adjustment [mm]
L = Total Timing Belt length [mm]
F
P
= Pre-tensioning force for Timing Belt [N]
F
Bperm
= Permissible force for Timing Belt [N]
F
x
= Operating load [N]
T
F
= Frictional torque, loss of friction when running light
[Nm] = 1 Nm
r
E
= Effective radius [mm] = 23.87 mm
C = Constant of expansion [N]
The calculated tensioning adjustment can be checked by various means.
Typical tools include frequency analysis tools, strain gauges and simple length
measuring devices.
Tip:
The necessary elongation calculated for the Timing Belt is constant along its
full length.
The actual elongation of the Timing Belt as calculated for this segment can
be checked and thus adjusted by marking a specific length on the Timing Belt
(e.g. 1 m) and using a steel ruler.