MHT258a (Engl.)11-1
11. APPENDIXES
11.1 Model type selection
(1) Load machine system
Load machine systems driven by adjustable (variable) speed motor are generally as follows.
Mechanical system Description
Ball-screw (with direct coupling) Used for high-accuracy positioning in a short dimension.
Ball-screw (with reduction gear) Load torque is increased through deceleration. Compensation is required for gear backlash.
Rack and pinion Used for positioning in a large dimension.
Movement per revolution of pinion involves a π value. π compensation is required.
Conveyor (with timing belt)
Used for light loads. πcompensation is required.
Chain drive Mostly used for transfer line, etc.
For positioning, countermeasures for chain elongation is needed.
Reduction ratio is large. Moving speed of load machine system is low.
Feed roll drive A material having a plate shape is emitted and sandwiched between rolls.
An error appears over a large length due to a difference in roll diameter.
π compensation is required. Feed amount becomes inadequate due to slip at rapid accel./decel..
Table indexing A large reduction speed ratio is required for a large inertia moment of the machine table.
Rotational speed of the table is low and a worm-gear is often used.
Spindle dreive In winding of wire material, etc., inertia moment becomes larger. Larger reduction speed
is necessary.
For constant peripheral velocity control, a control system should be checked.
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