Belt tension meter

It is a sonic belt tension meter.
Calculate the tension (unit: N) of the belt (timing belt etc) tightened between the pulleys from the frequency when the belt is played.


Measurement method

1, initial setting
I will set the belt.
1) Press the setting button.
Enter the state of the belt you want to measure.
1, the number of teeth of the left and right pulleys and the number of teeth of the belt.
2, pitch of belt mm.
3, Unit Length Weight g / (m · mm) ≒ Belt Width: 1 mm x Belt Length: Weight of 1 m g.
4, width of belt width mm.
Note) When the unit of weight per unit weight of belt is kg / m (weight per kg)
3, W (kg / m) x 1000 in unit length mass
4, Please enter 1 in the width of the belt!

2, measurement
1) Move the smartphone's caller to the center of the belt you want to measure and press the start button.
(The display under measurement will be done.)
2) Play the center part of the belt and generate a sound like a string.
(When playing the belt, its frequency converges to a certain frequency corresponding to the tension of the belt.)
3) If vibration of a certain frequency of the belt is detected, the tension (unit N) of the belt calculated by setting the frequency of the sound when it is detected, its frequency and the belt set with 1 is displayed on the monitor. (If you do not measure well, try removing the surrounding noise or adjusting the sensitivity (+ - button))
Increasing the sensitivity cuts out small sound vibrations, and conversely lowering the sensitivity also detects small sound vibrations, but it makes detection of noise noise easier.
The maximum detection frequency is 400 Hz.

Caution
This tool uses the recording function of smart phone, and obtains the obtained waveform
A certain frequency is detected with a simple method.
For this reason, please use measurement results and accuracy as a guide only.

Remarks
Calculation formula of belt tension conversion from frequency is carried out by the following calculation.


Remarks
Calculation formula of belt tension conversion from frequency is carried out by the following calculation.

Hz: Measurement frequency / sec
T 1: pulley 1 number of teeth
T 2: Number of pulleys 2 teeth
B: Number of belt teeth
P: Belt pitch mm
M: Belt unit mass g / m.mm (1 mm width x 1 m belt weight g)
W: Belt width width mm
Note) When unit of mass per unit weight of belt is set to kg / m (weight per kg)
M = W (kg / m) x 1000, w = 1 (mm) Please enter!

Z: Pulley shaft length
S: length of linear portion of belt
R1: Pulley 1 radius
R 2: Pulley 2 radius
Pi: Pi = 3.14 ,,,

R 1 = t 1 × p / pi
R 2 = t 2 × p / pi

Z = (b + (b ^ 2- 8 x (r 1 - r 2) ^ 2) ^ 0.5) / 8
S = (Z ^ 2- (r 1 - r 2) 2/4) 0.5

Belt tension N = 4 × m × w × S ^ 2 × Hz 2 × 10 ^ - 9