Dynamic Simulation And Contact Characteristic Analysis Of Centrifugal Disengaged Overrunning Clutch

Centrifugal disengaged overrunning clutch is an important branch of slanted overrunning clutch.It is widely used in the auxiliary power unit(APU)of helicopters.It is located between the DC motor and the APU gearbox gear train.Its main function is to control the DC motor and gears The engagement and disengagement between the box gear trains has the characteristics of small radial size,light weight and high rotational speed.In this paper,the centrifugal disengagement type overrunning clutch is taken as the research object,and the dynamic contact characteristics of the centrifugal disengagement type overrunning clutch are studied by the combination of theoretical calculation analysis,dynamic simulation and experimental verification.The main research contents are as follows:(1)Analyze the geometric configuration of the wedge of the centrifugal disengagement type and the calculation method of the contact angle;through the analysis of the mechanical characteristics of the centrifugal disengagement type overrunning clutch in the wedging state,it is deduced that the clutch wedge in the wedging state and the inner,the theoretical stress calculation method of the outer raceway;analyze the relationship between the spring force and the deformation amount;deduce the conditions for the clutch to realize self-locking based on the load conditions of the clutch and the principle of self-locking;Analyze and derive the minimum critical speed when the wedge is completely disengaged from the raceway.(2)Abandoning the previous practice of directly ignoring the spring plate in the simulation of the inclined brace overrunning clutch,the spring preforming simulation method is proposed,and the dynamic simulation model of the centrifugal disengaged overrunning clutch is established with the addition of the spring plate structure.Ls-Dyna software was used to simulate and analyze the two working conditions of centrifugal disengaged overrunning clutch: APU starting condition and air starting condition.The contact stress variation law and relative sliding displacement between wedge and raceway in the process of centrifugal disengaged overrunning clutch wedging were obtained.(3)Explore the influence of non-structural parameters such as installation error of inner and outer ring,cage manufacturing error,friction coefficient between wedge and raceway and spring stiffness on contact characteristics of centrifugal disengaged overrunning clutch,and establish a series of dynamic simulation analysis models.The influence of different non-structural parameters on contact characteristics of centrifugal disengaged overrunning clutch is obtained by finite element simulation.(4)Carry out the dynamic test experiment of the clutch,build a test-bed,and measure the relative sliding displacement between the wedge and the raceway and the tightening torque of the spring plate during the wedging process of the centrifugal disengaged overrunning clutch.Compare the experimental results with the simulation data to verify the effectiveness of the simulation method.