Analysis of a Ramp Roller Clutch System

In this effort, a procedure is developed to apply finite element method (FEM) in the nip angle solution of a ramp roller clutch system. The challenge in the analysis of a ramp roller system is to determine the final nip angle. Traditionally, this angle is calculated by an analytical method which involves solving an implicit function equation through an iterative process. However, the drawback of this analytical method is that the Hertz contact deformation is neglected. The Hertz contact is caused by the contact of the rollers with the outer housing and the cam shaft. Neglecting the Hertz deformation causes underestimation of the nip angle and may create an unsafe operating condition for the clutch system. If the system's maximum nip angle is exceeded, the clutch will not function and the aircraft will lose power. Therefore, a modified analytical method, which includes the Hertz contact effect along with finite element method, are utilized in the current work to show improved prediction accuracy of the final nip angle. In the finite element analysis, it was determined that this problem involves large displacement and small deflection. An innovative method is proposed in determining the final nip angle using FEM method. The solutions from the traditional analytical method, the modified analytical method and the FEM method are presented and compared and discussion are made.