4
Fig. 1 Oscillation attenuation of timing belt
Fig. 2 U-507 relation between measured value and actual tension
２
150
100
50
0
0
100
200
300
400
500
600
100
200
300
400
500
600
50
100
150
Timing belt:
3GT tooth shape x 3 mm wide
（V）
０
-２
TIME A
LIN
８０mS
３
.Measurement principle of U-507
When a belt tensed between pulleys is subjected to impact
and vibrated, it oscillates first with an irregular waveform
containing high frequency component and impact component
as shown in figure 1, but soon oscillates with a intrinsic
regular waveform.
U-507 tension meter was created in consideration of well-
known phenomenon described above, but the belt and wire
attenuate in a very short time, and no simple device has
existed which captures the cycle of such basic waveform.
However, a unique data processing method was developed
which captures oscillation frequency making full use of
microcomputer, and an attempt was successful to catch the
cycle of such waveform rather easily.
This system detects oscillation waveform with a microphone,
and the microcomputer processes the data and converts to
characteristic frequency. "Horizontal oscillation of string" set
on the tension meter described on the right in calculating the
belt tension.
Here, the belt and the wire have a rigidity, which is different
from the string, therefore U-507 measurement displayed is
somewhat higher than the actual tension under the affected
condition.
Therefore it is allowed to obtain correction factor by strict
calibration test and incorporate it to the data input, thereby
displaying more accurate tension.
An example of calibration result of U-507 measurement and
actual tension is shown below:
Calculation formula To = 4 x M x W x S
2
x f
2
x 10
-9
Where,
Therefore, it is required to input the length of span to be
measured and the mass of belt (unit mass x width) by use of
numeric key
3GT belt
Actual tension (N)
11. Actual tension (N)
U-507 measured value (N)
U-507 measured value (N)
：
Span length 86 mm
：
Span length 154 mm
：
Span length 365 mm
：
Span length 365 mm
[9 mm wide]
Standard installation
tension of belt
9 mm wide
Typical tension when
stretching again
Typical
installation
tension
Standard installation
tension of belt
6 mm wide
[6 mm wide]
V riffed belt (3PK) belt
：
Span length 102 mm
：
Span length 201 mm
：
Span length 400 mm
To: Tension (N)
M: Unit mass (g/mm wide x m long)
W: Belt width or number of ribs (wires) (mm/R)
S: Measured span length (mm)
f: Horizontal characteristic frequency (Hz)
Summary of Contents for U-507
Page 15: ......
