Linear Motion Control

Roh’lix Actuators have six precision ball bearings, three at each end of a two-piece aluminum block.

Mounted at an angle relative to the drive shaft axis, the bearings convert drive shaft rotation into proportional linear travel. This is called lead. The linear thrust capability of the Roh’lix is determined by the friction between the smooth surfaces of the angled bearings and the drive shaft.

Thrust capability is varied by adjusting the cap screws located on the top of the load block. Loads exceeding the thrust setting cause the Roh’lix to stop while the bearings rotate in place as long as the drive shaft is turning.

OPERATING CHARACTERISTICS:

Efficiency
The rolling contact between the outer races of the six ball bearings and the driveshaft provides a smooth, quiet linear motion, resulting in a minimum of 90% efficiency.

Backlash
Roh’lix bearings are preloaded by the coil springs to reduce backlash to less than 0.001 inch, which help maintain consistency throughout the life of the bearings.

Positioning Accuracy
The Roh’lix is a friction drive device and as a result, will show an accumulated error that is, in general, up to 0.002 inches per shaft revolution. Where greater accuracy is required, linear encoders can be used to indicate position.

Overload Protection
The Roh’lix has the ability to slip if an obstruction is encountered in the system. This unique advantage over other types of linear actuators can prevent damage and costly downtime.

Lubrication
Roh’lix bearings are factory-lubricated for life and are designed to run on a clean, non-lubricated driveshaft.

Shafting
Recommended driveshaft material is C-1060 hardened and ground shafting with a minimum hardness of HRC 58. Its hardness will provide optimum life expectancy and its ground surface provides a uniform friction surface. Stainless steel shafting, although slightly softer, is adequate for many applications requiring corrosion protection.

Temperature
Acceptable temperature range is -10°F to +180°F. Special units available for higher or lower temperatures.

Maintenance
Unit is maintenance free, however, the shafting may require occasional wiping to clean off foreign matter that may accumulate.

Backdriving
By applying a thrust load to the Roh’lix unit, the shaft can be made to rotate. The thrust load will cause the Roh’lix and any device attached to it to travel along the shaft. Therefore, the Roh’lix should never be relied upon as the sole device to hold position.

Tandem Roh’lix
Two Roh’lix may be used on a common shaft in series, or in parallel on separate shafts, however, the combined thrust rating must be derated by 20%. When installing the Roh’lix units, be sure to tighten the thrust adjustment screws an equal number of turns so that they share the thrust load equally.

• Choose from 5 different sizes, a wide range of leads and various shaft diameters to find the right one for your application.
• Easy installation. The 2-piece split aluminum block can be assembled around the shaft without necessitating the removal of driveshaft and/or pillow-block bearings.
• Roh'lix has the ability to slip in the event of a jam-up, protecting product equipment.
• Adjustable thrust setting can be set precisely to carry the load without slipping, but not so high that the Roh'lix builds up unnecessary thrust before overloading.
• Roh’Lix Linear Actuators are extremely efficient (over 90%). Long life which ranges from 2 million to 10 million inches of linear travel.
• Coil springs for thrust adjustment. Preloads bearings to minimize backlash to less than 0.001 inch. Minimal backlash stays consistent throughout the lifetime of the unit.
• Socket-head shoulder screws to mount the bearings to the block allows for easy bearing replacement.