Design and Analysis of a New Straight Round Flexible Hinge_Hinge Knowledge

Revised

Abstract:

To achieve a flexible hinge with improved flexibility and higher rotational precision, a novel design for a straight circular flexible hinge was developed. The flexibility, precision, and fatigue life of this new hinge were compared and analyzed against a traditional straight circular flexible hinge. The results demonstrated that the new straight circular flexible hinge exhibited greater flexibility and higher rotation accuracy compared to the traditional hinge. The fatigue life of both hinges is close to infinite. Overall, the new flexible hinge outperformed the traditional hinge and met the design requirements.

1.

Flexible hinges have been the subject of extensive research due to their applications in micro-electromechanical systems, precision instrumentation, and micromanipulation. These hinges are small in size, gapless, devoid of mechanical friction, and highly sensitive. Researchers have shown interest in the design of flexible hinges [1-3]. Critical properties of flexible hinges include stiffness (flexibility), precision, and stress characteristics [4-5]. Since flexible hinges are prone to fatigue failure compared to rigid structures, fatigue analysis is necessary during the design phase [6-7].

In this paper, a new design for a straight circular flexible hinge is presented. The flexibility, precision, and fatigue life of this hinge are analyzed using finite element software Workbench 15.0. The performance of the new hinge is compared to that of the traditional straight circular flexible hinge.

2. Hinge Performance Analysis

To design a reliable flexible hinge, it is essential to analyze its fundamental characteristics. The primary performance parameters of a flexible hinge include flexibility, precision, and fatigue life.

2.1 Flexibility Analysis

Flexibility (stiffness) is a crucial design parameter for flexible hinges. Equation (1) shows that when other parameters remain constant, a smaller hinge width (b) results in greater flexibility. Therefore, the new straight circular flexible hinge, with a narrower incision width (b1), exhibits enhanced flexibility. Finite element analysis using Workbench 15.0 was conducted to verify the flexibility of the two hinges. The same material properties, load, and boundary conditions were applied for both hinges. Stainless steel, with an elastic modulus of 190 GPa and a Poisson's ratio of 0.305, was chosen as the material for the hinge model. The dimensions of the traditional straight circular flexible hinge were: hinge length (a) = 30 mm, width (b) = 10 mm, height (h) = 10 mm, minimum thickness (t) = 1 mm, and arc radius (r) = 4.5 mm