10
18
0
14
0
60
12
0
80
Ø25
320
19
⌀5.5
40
20
⌀10.5/5
40
19
44
Δ
L = L
F
V
_______
1000
K
Similar to the picture
The corresponding holes, grooves and fastening materials are provided on
Slide LRF for the purpose of fixing the tensioning elements in place. When
working with high loads, the Fixing Block needs to be pinned (Dowel Pin ISO
2338, ⌀ 6 mm) The prepared ⌀ 5.5 mm holes determine the position of the
Dowel Pins.
Insert both ends of the Timing Belt into the Tensioning Blocks so that the cavity
inside each Tensioning Block is filled then screw securely into place. Fix one
Tensioning Block in place under the carriage plate and use the other to tension
the Timing Belt with the aid of the long Hexagon Socket Head Cap Screws of
the centrally located Fixing Block. When doing so, adjust the two tensioning
screws alternately to ensure the tension on the Belt is evenly distributed.
The necessary Timing-Belt tension must be determined and set in line with the
anticipated loads.
Tensioning screws
Timing-Belt Tensioner, Tensioning Block 8 R25, 0.0.426.29 [b]
Timing-Belt Tensioner, Fixing Block 8 R25, 0.0.426.30 [a]
If the LRE 8 D25 ZU 80 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 alternately 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] = 2400 N
F
x
=
Operating load [N]
T
F
=
Frictional torque, loss of friction when running light
[Nm] = 2.3 Nm
r
E
=
Effective radius [mm] = 44.56 mm
C =
Constant of expansion [N] = 500 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.
