Eaton EAO-6206A - Gear Ratio

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EA(B)O-6X06 01/2018 Rev. 1 1. General Information
Gear Ratio
Denition and Calculation
Gear ratio of a transmission speed is the relationship between the transmission’s output and input speeds, with
the said gear shifted. If the gear ratio is greater than 1, it means that the transmission’s output speed is slower
than the input speed and it is said that there is a reduction in the speed. On the other hand, if the gear ratio is
less than 1, the transmission’s output speed will be faster than the input speed and, in this case, it is said that
there is an overdrive.
The gear ratio is calculated by dividing the number of teeth of the driven gear by the number of teeth of the driving
gear of that specic speed and multiplying by the ratio of the input gear set.
Example:
Input gear ratio = C ÷ I (input gear set) = 44 ÷ 29 = 1.52
1st speed ratio = M ÷ C (1st speed) x 1,52 (input gear set) = 49 ÷ 12 x 1,52 = 6.19
This means that the 1st speed gear ratio is 6.19:1 or, in other words, with the transmission shifted into the 1st
speed, the engine (input shaft) makes 6.19 revolutions for every revolution of the transmission’s output shaft.
So, in 1st gear, there is a reduction in the output speed.
EA(B)O-6106/6206A EA(B)O-6106/6206B
Torque
N.m 600 600
Lb.ft 442 442
Z Ratio Z Ratio
Input Shaft (I)
Countershaft (C)
29
44
1.52
29
44
1,52
1st Countershaft (C)
Mainshaft (M)
12
49
6,19
12
49
6,19
2nd Countershaft (C)
Mainshaft (M)
17
38
3,39
17
38
3,39
3rd Countershaft (C)
Mainshaft (M)
27
37
2,08
27
37
2,08
4th Countershaft (C)
Mainshaft (M)
33
29
1,33
33
29
1,33
5th Countershaft (C)
Mainshaft (M)
Direct 1,00 Direct 1,00
6th Countershaft (C)
Mainshaft (M)
47
24
0,77
52
25
0,73
Reverse Countershaft (C)
Reverse Idle Gear (R)
Mainshaft (M)
12
29
45
5,69
12
29
45
5,69
Z = Number of teeth
C = Countershaft
M = Mainshaft
R = Reverse Idle Gear
I = Input Shaft
Gear Ratio