Technical Data  Reducers  Miter and Bevel Gear Boxes  Selection

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ARA Gear Box Selection

Required conditions

(1)Load torque or transmission kW 　(2)Input speed 　(3)Reduction Ratio 　(4)Load characteristics 　(5)Start/Stop frequency

Selection procedure

Consider the requirements and select a model according to the following guide.

1. Determine the service factor

The transmission capacity values in the catalogs are all based on a service factor of 1.0.

Find the service factor from the service factor table (Table 1) according to operating conditions.

Table 1 Service factor

Load characteristics Operating hours
2 hours 10 hours 24 hours
Constant load 1.00
(1.00)		 1.00
(1.25)		 1.25
(1.50)
Load with light impact 1.00
(1.25)		 1.25
(1.50)		 1.50
(1.75)
Load with heavy impact 1.25
(1.50)		 1.50
(1.75)		 1.75
(2.00)

Note)

  • 1. Use the values in parentheses if operation stops 10 times or more in an hour or when using a multi-cylinder engine as the motor
  • 2. The service factors in the table above are to be used as a general reference. Decide on the service factor according to the operating conditions.

2.Calculate the corrected torque or corrected kW

Calculate the corrected torque or corrected kW using the service factor (Table 1).

Corrected torque or corrected kW = (Load torque or transmission kW applied to the ARA Series) × Service factor (Table 1)

3. Find the model

  • ・Use the transmission capacity table (see product page) to select the size that satisfies the corrected torque or corrected kW at the operating rotation speed.
    Next, check whether the peak torque at start/stop is within 200% of the transmission capacity of the selected size.
  • ・Select appropriate models from the Shaft Arrangements and Rotation Details section.

4. Calculate the radial load

When driving a system by mounting a sprocket, gear, and/or pulley on the lateral shaft or cross shaft, calculate the radial load by using the following formula:

・Radial load calculation formula

Allowable Radial Load ≧ T × f × Lf r
(Allowable Radial Load )

  • T = Correction torque N・m
  • f = O.H.L. factors (Table 2)
  • Lf = Load position factors (Table 3)
  • r = Pitch radius of sprocket or pulley m

Note) If the calculated radial load is greater than the allowable radial load, the r value, which is the pitch radius of the sprocket or pulley, must be greater than that used in the calculation.

Table 2　O.H.L. factors (f)

Chain 1.00
Gears
Toothed belt 		1.25
V belt or heavy duty toothed belt 1.50
O.H.L. factors

Table 3 Load position factors (Lf)

Load is applied at the shaft center or closer to the gear box ℓ ≦ Q 2 Lf = 1
Load is applied farther than the shaft center ℓ > Q 2 Lf = 2ℓ Q

Q = Length of output shaft end 　ℓ = Radial load position

Note) Contact us if radial and axial loads are applied at the same time.