Product category:
Ballscrews, Linear Guides, Jacks, Dampers
News Release from: Abssac | Subject: Satellite roller screws
Edited by the Engineeringtalk Editorial
Team on 07 February 2008
Overcoming the limitations of ballscrews
Abssac reckons its satellite roller screws offer formidable advantages in the linear technology sector.
With a traditional ballscrew design, the captivated ball bearings transfer the load between the screw and nut as they recirculate in the ball nut housing To increase the load capacity of the ballscrew you have to either increase the number of ball bearings in the nut housing, for example by doubling the actual ball returns; or alternatively you have to increase the amount of times the ball bearings recirculate within the ball nut housing
This article was originally published on Engineeringtalk on 22 Oct 2004 at 8.00am (UK)
Related stories
Roller screws beat ball screw performance
A new range of satellite roller screws from Abssac are high-precision linear devices that transform rotary movement into a linear movement.
Roller screws transmit more load
Abssac reckons its new programme of satellite roller screws is a formidable product range.
Of course the final option is to choose a larger, more expensive ballscrew.
All these options ultimately increase the load capacity, but in every case there is still a limitation of the actual load bearing surface area per ball bearing.
This is where the satellite roller screw has a legitimate advantage.
Further reading
Pharmaceutical firm uses roller screws
Abssac has supplied a bespoke set of satellite roller screws to a pharmaceutical company, providing precision axial movement in the enhanced manufacture of tablet form medication.
Satellite roller screw transmits high loads
The many points of contact give a satellite roller screw greater rigidity and shock tolerance than a ball screw without a compromise in friction or efficiency.
A satellite roller screw employs, matched rollers to rotate (or satellite as the product name suggests) around the screw during actuation instead of ball bearings.
By its inherent design, there is an immediate increase in the physical number of contact points on the screw that can support the load compared with that of the same diameter ballscrew.
The admissible static and dynamic load capacities are therefore considerably higher than that of a ballscrew for the same diameter.
In fact the static load can be 3x greater than that of ballscrews and their lifespan is 15x longer.
The many points of contact also give a satellite roller screw greater rigidity and shock tolerance than a ballscrew without a compromise to friction or efficiency.
Another key feature of satellite roller screws is that they can rotate significantly faster and support much greater accelerations than ballscrews as there is no recycling of the ball bearings.
In fact, a roller screw mechanism can handle twice the rotation speed of a ballscrew.
Taking the product to another level, it is possible to supply planetary roller screws with smaller leads compared with ballscrews.
As the lead is a function of the pitch of the planetary roller screw, the lead can be very small (0.5mm and even less).
The lead can be chosen and supplied without any geometrical changes of both the screw shaft and the nut body.
In a ballscrew the lead is limited by the dimension (outside diameter) of the bearing ball, which is a standard feature.
The Abssac satellite screw product has two standard designs directly aimed at replacing less effective ballscrew designs.
There is also a full design capability of the standard satellite screw programme which continues to "upgrade" linear designs around the world.
Applications to date have included aerospace, medical, exploration and machine tools. Request a free brochure from Abssac ...
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