What is the effect of the end design of stainless steel torsion spring on its performance

Stainless steel torsion spring is an important mechanical element. Its working principle is to apply angular displacement around the spring axis to generate elastic deformation, thereby storing energy and releasing it when unloading to achieve functions such as resetting, driving or holding. In this process, the transmission of torque depends entirely on the connection effect between the spring end structure and the external component. If the end design is improper, such as too large size error of the connection structure, mismatched shape, insufficient contact surface or unstable positioning method, the torsional force will not be effectively transmitted, which will lead to functional failure or unstable spring operation. Therefore, ensuring the tight fit of the end shape with the assembly, with good clamping and angle conductivity, is the key to preventing the spring performance from deteriorating due to sliding, deformation or dislocation.

The geometry of the end is one of the core factors affecting the performance of stainless steel torsion springs. Common end structures include straight arm type, bent arm type, hook end, flat sheet type, square and customized type. Different structures show their own unique connection characteristics and torque transmission methods in different application scenarios. The straight arm structure is suitable for environments with small space restrictions and clear fixed points, because it has a clear force transmission direction, high processing accuracy, and relatively convenient positioning and assembly; while the bent arm structure is suitable for systems that need to bypass other structures or perform multi-axis linkage, and it has good structural avoidance and torque transmission capabilities. The hook-shaped end design facilitates quick assembly and disassembly, and is suitable for light-load mechanisms and quick replacement scenarios, but may face the problem of insufficient structural strength when high torque is transmitted. Square ends or customized special-shaped ends are often used in special equipment, which can achieve more precise angle control and torque coupling to meet the special needs of complex force paths. Therefore, in the process of structural design, the actual force conditions, assembly conditions, spatial layout and manufacturing feasibility must be comprehensively considered to select the most suitable end form.

In addition, the end angle design is another key factor to ensure the matching of spring performance and installation. The angles of the two end arms of the stainless steel torsion spring directly determine its preload angle and working angle range in the installed state. If the end angle is designed too small, the preload is insufficient, and the spring cannot provide enough initial torque in the assembly state, which will affect the start-up response of the system function; if the angle is designed too large, the spring may enter the plastic zone due to excessive deformation during the assembly process, resulting in permanent deformation or stress damage, thereby shortening the service life. Therefore, the design of the end angle must be accurately calculated and checked in combination with the initial position and maximum working angle of the system to ensure the reliability of the structure and provide the required torque output.

The end connection method directly affects the assembly stability and load distribution uniformity of the spring, thereby affecting its fatigue life and reliability. In high-frequency or high-load applications, if the end structure is not designed reasonably, stress concentration or micro-friction may occur at the connection point. These phenomena often become the starting point of fatigue cracks, which seriously affect the cycle life of the spring. By reasonably controlling the curvature radius, transition section length and processing accuracy of the end, and optimizing the contact surface and contact angle with the connection parts, the local stress peak can be effectively reduced, and the structural integrity and fatigue resistance of the spring under cyclic loading can be improved. In addition, the connection transition section between the end and the main spring body should avoid sharp corners or sudden changes. It is recommended to adopt a smooth transition or stress dispersion design to prevent the risk of fracture in the stress concentration area.