Chain Drive
In a system with a chain drive, the following must be considered:
the weight and size of drive sprocket and any attaching hub
the weight and size of the driven sprocket and shaft
the weight of the chain
the weight of any material or parts being moved
Weight of
chain
Weight and size of drive
sprocket and hub
Weight and size of driven sprocket,
shaft and any material or parts being moved
Figure B.6: Chain Drive System Inertia Considerations
Once the system inertia (JL) has been calculated in
Jref = JL ⎟ Ζ2
Where:
JL = System Inertia in
Jref = Reflected Inertia in
Z = Gearbox Ratio
The ideal situation would be to have a 1:1 system inertia to motor inertia ratio. This will yield the best positioning and accuracy. The reflected inertia (Jref) must not exceed 10 times the motor inertia.
Your system may require a reflected inertia ratio as close to 1:1 as possible. To achieve the 1:1 ratio, you must calculate an Optimal Gearbox Ratio (Zopt) which would be the square root of JL divided by the desired Jref. In this case since you want the system inertia to match the motor inertia with a 1:1 ratio, Jref would be equal to the motor inertia.
Zopt = JL ⎟ Jref
Where:
Zopt = Optimal Gearbox Ratio
JL = System Inertia in
Jref = Desired Reflected Inertia in
Appendices |
|
