Simulation investigation of ball screws for high speed transmitting systems

• Autorzy: Sobolewski J. Z. , Małkiński J. , Pieniecki P.
• Języki publikacji: EN

Abstrakty

EN

The ball screws are used in feed systems in CNC machines working with constantly higher cutting speed. When the speed of the balls reaches certain levels, the repetitive chock (impact forces) generated by the balls in the "transient" phase of the balls' motion and forces acting in the return channel cause damage to the recirculation ball system. A simulation of impact forces for variable length of transient phase in function of the rotational speed was made. The static axial rigidity is a very important factor to be considered in defining ball screws performance and exerts a major influence on positioning accuracy of NC machine tools. One of rigidity components is the balls/balltrack area rigidity, dependent on Hertz's deflections. However, due to machining inaccuracies, the ball screws properties (especially rigidity) are considerably lower than the theoretical ones. A coefficient known as the geometric correction factor makes it possible to predict the rigidity of the ball screw. A computer simulation of the influence of machining inaccuracies on contact deflections, rigidity and servo drive resonance was carried out. It was examined what rotational speeds set off the harmful phenomenon of the agreement of the frequency of the arrangement of the impact forces with the frequency of the servo drive system resonance. The presented method allows for the calculation of the impact forces, total rigidity and resonance of NC machine feed system, in the preliminary phase of technical project.

Słowa kluczowe

EN

ball screw; CNC feed systems; rigidity; impact force

• Wydawca: Wydawnictwo Wrocławskiej Rady FSNT NOT
• Czasopismo: Journal of Machine Engineering
• Rocznik: 2008
• Tom: Vol. 8, No. 4
• Strony: 59--67
• Opis fizyczny: Bibliogr. 7 poz., rys.

Twórcy

autor

Sobolewski J. Z.

• Institute of Machine Design Fundamentals, Warsaw University of Technology

autor

Małkiński J.

• Institute of Machine Design Fundamentals, Warsaw University of Technology

autor

Pieniecki P.

• Warsaw Institute of Aviation

Bibliografia

• [1] HUNG J.P., WU J. S.S. Wu, CHIU J.Y., Impact failure analysis of re-circulating mechanism in ball screw. Engineering Failure Analysis, Elsevier Ltd., 2004, 561-573, www.elsevier.com/locate/engtailanal
• [2] KOSMOL J., Servo drives of NC machines tools (in polish), WNT Warszawa, 1998.
• [3] SOBOLEWSKI J.Z., MAŁKIŃSKI J., Estimation of the influence of machining errors on ball screw rigidity, Journal of Machine Engineering, Vol. 6, No. 2, Wrocław 2006, 37-44.
• [4] SOBOLEWSKI J.Z., Selected problems of ball screw noise. Machining Engineering, Vol.4, No. 1-2, Wroclaw 2004, 193-200.
• [5] SOBOLEWSKI J.Z., Criteria of Ball Screws Selection for CNC Machines, Journal of Machine Engineering, Vol. 7, No. 1, Wrocław 2007, 42-50.
• [6] ISO 3408-4: 2006, Ball screws - Part 4: Static axial rigidity.
• [7] Catalog Rexroth Bosch Group, http://www.boschrexroth.pI