Parker Hannifin 88-020292-01 A Connect the Motor to the Load -COUPLERS, Misalignment Condition

7–CONNECT THE MOTOR TO THE LOAD –COUPLERS

Align the motor shaft and load as accurately as possible. In most applica- tions, some misalignment is unavoidable, due to tolerance buildups in components. However, excessive misalignment may degrade your system’s performance. The three misalignment conditions, which can exist in any combination, are illustrated and described below.

Aligned

	Angular Misalignment
End Float	Parallel Misalignment

Combined Parallel & Angular Misalignment

Misalignment Condition

•Angular Misalignment: The center lines of two shafts intersect at an angle other than zero degrees.

•Parallel Misalignment: The offset of two mating shaft center lines, although the center lines remain parallel to each other.

•End Float: A change in the relative distance between the ends of two shafts.

The type of misalignment in your system will affect your choice of coupler.

SINGLE-FLEX COUPLING

Use a single-flex coupling when you have angular misalignment only. Because a single-flex coupling is like a hinge, one and only one of the shafts must be free to move in the radial direction without constraint. Do not use a double-flex coupling in this situation: it will allow too much freedom and the shaft will rotate eccentrically, which will cause large vibrations and catastrophic failure. Do not use a single-flex coupling with a parallel misalignment: this will bend the shafts, causing exces- sive bearing loads and premature failure.

DOUBLE-FLEX COUPLING

Use a double-flex coupling whenever two shafts are joined with parallel misalignment, or a combination of angular and parallel misalignment (the most common situation).

Single-flex and double-flex couplings may or may not accept end play, depending on their design.

RIGID COUPLING

Rigid couplings are generally not recommended, because they cannot compensate for any misalignment. They should be used only if the motor or load is on some form of floating mounts that allow for alignment com- pensation. Rigid couplings can also be used when the load is supported entirely by the motor’s bearings. A small mirror connected to a motor shaft is an example of such an application.

COUPLING MANUFACTURERS

HUCO	ROCOM CORP.	HELI-CAL
70 Mitchell Blvd, Suite 201 5957 Engineer Drive		P.O. Box1069
San Rafael, CA 94903	Huntington Beach, CA 92649	Santa Maria, CA 93456
(415) 492-0278	(714) 891-9922	(805) 928-3851

28 E-AC Drive Hardware Installation Guide Chapter 2 – Installation