Abstract

With the development of the more electric aircraft (MEA), electromechanical actuator (EMA) are gradually becoming a popular alternative to traditional hydraulic actuators. The electromechanical actuator (EMA) brings weight reduction, improved maintenance and becomes more feasible to realize integrated control for flight control executive system. However, regarding the utilization of EMAs in the primary control surface, the major concern is the mechanical jamming, which is critical and potentially disastrous for aircraft. The mechanical jamming mainly refers to the ball screw pair which is widely used in EMAs. Therefore, the jamming mechanism and jam-tolerant capability of the ball screw transmissions are researched and discussed in this paper to find the fact that causes jam failure. Firstly, the structure composition and working principle of the ball screw pair is introduced, and gives possible reasons for jam phenomenon. Then the kinetic and dynamic model is built when the ball moves in the raceway and through the inverter considering elastic-plastic contact deformation. Meanwhile the load distribution and deformation compatibility between adjacent balls are considered, as the viscous damping force and centrifugal force are also contained. Accordingly, the friction self-locking condition for the ball in the raceway is proposed, which could be seen as a criterion for the occurrence of the jam. The variation of contact angle and friction coefficient in different operating conditions of load, velocity and frequency are analyzed and compared. The structure parameters as altitude intercept between the raceway and inverter, the returning spiral curve are also discussed. Finally, optimized design and improved operating parameters are suggested from the view of reducing the probability of jamming.

Highlights

  • With the development of the more electric aircraft (MEA) electromechanical actuator (EMA) are gradually becoming a popular alternative to traditional hydraulic actuators

  • The mechanical jamming mainly refers to the ball screw pair which is widely used in EMAs

  • Based on the exploration of previous studies, the reasons for jamming failure of ball screw pairs could be attributed to the following situation: 1)friction self-locking due to plastic deformation or wear in the raceway

Read more

Summary

Introduction

With the development of the more electric aircraft (MEA) electromechanical actuator (EMA) are gradually becoming a popular alternative to traditional hydraulic actuators. Regarding the utilization of EMAs in the primary control surface, the major concern is the mechanical jamming which is critical and potentially disastrous for aircraft. Due to the particularity of various loads and working conditions, the bearing characteristics, failure forms and jamming mechanisms are usually different. The dynamic behavior of ball screw pairs under high speed or overload are typically complicated and not systematically studied from theoretical and experimental aspects. Under the working conditions of high speed and heavy load, the collision impacts of the balls in raceway, the plastic deformation between two contact surfaces, as well as rapidly changing curvature of the return groove may cause jamming failure. The jamming mechanism and jam-tolerant capability of the ball screw transmission are researched and discussed in this paper to find the fact that cause jam failure. Optimized design ideas and improved operating parameters are suggested from the view of reducing the probability of jamming

Modeling
Contact Analysis
Force analysis of the ball in returner channel
Numerical solution
Results
Conclusion

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.