RACO Precision Ball Screws
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RACO BALL SCREWS PRECISION IS OUR PROGRAM RACO Schwelm

RACO BALL SCREWS 2 Quality Management Statement 3 Introduction RACO Ball Screws 4 Precision Ball Screws / Technology 5 Structure Type of Nut Assemblies 7 Type Code / Technical Data All rights reserved. No part of this publication may be reproduced without the prior permission of the publishers. Specifications are subject to be changed without notice.

RACO Schwelm RACO BALL SCREWS 1 ABOUT US The cornerstone for RACO´s ball screws was laid more than 50 years ago based upon RACO´s own world-wide patents for single ball return arrangements, the ball groove profile, single ball nut preloaded and the short travel ball screw assembly. Further patents set the standard for high precision ball screws and electromechanical spring brake system, which operate as safety brakes in rail based public transportation systems. Since that time the effort for a “clean and environmental-safe solution” is our ambition and commitment. RACO Schwelm is among the...

RACO Schwelm RACO BALL SCREWS 2 QUALITY STATEMENT Extract from the quality manual Within the last years, comprehensive quality of all furnished work proved to be one of the most important factors for the success of a company. Quality is mostly defined as the “total of characteristics of a unit acc. to its adequacy to fulfil determined and demanded requirements”. One of the most important tasks of the management is to meet the requirements acc. to this “comprehensive product quality” by the permanent development of the Quality Management system acc. to DIN EN ISO 9001. Thus RACO was...

RACO Schwelm RACO BALL SCREWS 3 INTRODUCTION IN RACO BALL SCREWS The ball screw assembly consists of screw, nut and balls. The function is to transfer the rotary motion or into a linear motion into rotary motion. This is further extension and development of slide ball screw. The important significance of development is the same as changing a bearing from rolling motion to sliding motion. Because of excellent friction function, ball screw is widely used for all kinds of industrial equipment and precision instruments. RACO offers a wide range of ground ball screws to cover all requirements:...

RACO Schwelm RACO BALL SCREWS 3.1 Requirements and criteria for ball screws: The manufacturing is made upon request based on your drawing or technical info and the manufacturing procedures for each RACO ball screw will be selected individually according to the preferred criteria as outlined below. Each step of manufacturing is inspected for hardness and cracks to assure our defined high quality level which is documented in accordance to the ISO 9001/Rev.2000 ■ Load rating (static & dynamic) ■ Max. speed (critical speed) ■ Accuracy class (lead deviation) ■ Axial play (Preloading of nuts) ■...

RACO Schwelm RACO BALL SCREWS The RACO nut design The core of a RACO ball screw is the nut with its single lead ball return that has been developed by us. This design has been protected by a universal patent and ensures that the balls are returned within the ball screw nut at the shortest possible route. This gives you the benefit of a higher rated load with the smallest possible nut dimensions, meaning higher efficiency and a longer service life. RACO ball screws with a single or double nut (nut and counter nut) can be preset free from backlash, so that the correct and recurrent...

RACO Schwelm RACO BALL SCREWS Whatever you like The range of available RACO ball screws leaves very little to be desired. Our standard program includes spindles with a diameter from 6 up to 200 mm and lengths ranging from 80 mm to 8000 mm - each of them with different profiles and in different classes of accuracy. Smooth running, accurate positioning and high efficiency (good back driving) are the main benefits of our miniature ball screws. Nut is available with threaded end for easy mounting, with ball recirculation by integrated tube or inserts. It is typical that RACO accepts individual...

RACO Schwelm RACO BALL SCREWS Precise Reversibility Ball screw has not sticky friction like sliding screw. It clears crawl which exist during transference. Ball screw can realize two transfer wise-from rotary motion to linear motion and from linear to rotary motion- and transfer momentum. Ultra Power The internal design has been optimized to obtain ultimate static and dynamic capacities which are much higher than the standard range. Furthermore more the load capacity is independent of lead. The maximum load should not be applied on the nut mounting bolts but on the flange. Good...

RACO Schwelm RACO BALL SCREWS 4 PRECISION BALL SCREWS / TECHNOLOGY Ball screws are mechanism for changing rotary into linear motion and vice versa (Fig. 3). A ball screw assembly consists of the actual screw, the nut assembly with crossover for the return of the balls and the rolling balls. The balls roll in helical tracks in the screw and nut and form the only connection between them. The force transmitted is spread over a number of balls, so that the contact stress is relatively low. The rolling friction between the ball screw and nut results in an extremely low coefficient of friction....

RACO Schwelm RACO BALL SCREWS 4.1 Main fields of application The extremely high precision of the RACO ball screws makes them eminently suitable for metrology and control equipment, which is of decisive importance in the following fields of application: ■ Mechanical handling applications ■ Measuring and testing equipment ■ and your individual application An optimum pointed arch track profile (Fig. 4) is produced This profile has the greatest possible contact angle IS and good lubrication properties. Together with a ball diameter calculated to suit each application, it offers the following ■...

RACO Schwelm RACO BALL SCREWS 4.3 Ball Return System A crossover piece between each pair of adjacent threads returns the balls to the preceding thread for constant recirculation. After considering external return systems, extensive research work has led us to adopt a “S shaped” and furthermore a straight crossover piece. For standard leads this straight crossover piece is covered by German Federal Patent No. 2 149 392 and other foreign patents (Fig. 4 plug type “S shaped” crossover piece). nut balls crossover piece Fig. 5: RACO crossover piece (plug type) For large lead angles, the straight...