Capacity Selection

Information on selection of capacity

It is necessary to consider various factors when calculating the capacity of ordinary reducers.

1. Review of load torque

Load torque = Weight torque (Friction torque) + Acceleration torque (Inertia torque)
Weight torque: The turning force generated by the weight of the work (object)

T(Weight)=μ * F * r=μ * m * g * r

T: Torque(turning force) [N.m]
F: Force[N=kg m/secㆍ2]
g: Acceleration of gravity [m/secㆍ2]
r: Distance between the center of rotation and the center of gravity [m]
μ: Friction coefficient (horizontal: 0.1~0.2, vertical: 1)

T(Acceleration)=F * r=m * a * r

a: Acceleration [m/sec·2]

T(Inertia)= L * a

L: Moment of inertia [Kg m³]: different by shape
a: Each acceleration [rad/sec·2]

*Calculated by T(acceleration) in straight line motion and T(inertia) in rotary motion

2. Review of the moment of inertia

The moment of inertia refers to the property of an object generated by rotation and it is proportional to the weight and size of shape.
Moment of inertia of load

In order to increase the value of the moment of inertia, it is necessary to increase the capacity of motor or raise the reduction gear ratio. To decrease the value of the moment of inertia of load, the weight should be lessened, or the size should be cut down. If it is not reviewed enough, the Hunting phenomenon will occur causing rolling from side to side and it will lead to increase of Tec time.

The value of the moment of inertia is irrelevant to time, and the moment of inertia cannot be reduced by the increase of time.

3. Review of load of weight

The radial weight(Fr: shaft perpendicular weight) and thrust weight(Fa: shaft direction weight) on the output shaft of the reducer are written as the maximum weight value in the catalog of reducers, and they are calculated by below calculation method.

Load weight at the output terminal 〈Allowable weight of the reducer/(Shock weight coefficient*Operation coefficient*Distance coefficient*Safety ratio) (Call the head office for more details.)

4. Review of degree of precision

Back lash: the error caused by the gap between interlocking gears and is usually indicated by arc min(minute).
Angle of error: the range of error demanded by the customer for operation of equipment
Angle of error = Back lash of reducer + Torsional error of reducer + device part error

When reviewing the angle of error, it is essential to review the back lash of the reducer and other errors, too.
(Call the head office for more details.)