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This article presents a study on the transient dynamic responses of engagement process of one-way clutch using variable rectangular cross-section torsional spring, which is usually installed on the end of engine for preventing torque being transmitted back. A 2-degree-of-freedom torsional dynamic model is proposed in this article to study the engag...
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Citations
... They established finite element models for these clutches and employed finite element analysis to investigate the dynamic characteristics of variable cross-section overrunning spring clutches. Cao et al. [7,8] conducted research on the engagement dynamic characteristics of an overrunning spring clutch, establishing a dynamic model of the clutch engagement state. They discussed the physical parameters determining the torque during clutch engagement and conducted dynamic experiments on clutch engagement. ...
... For the torsion spring clutch, M = T n e 2πn f −1 [7], where T n represents the elastic torque, and for a spring coil with n turns, the friction torque is given by Equation (13): ...
... For the torsion spring clutch, = [7], where represents the elastic torque, and for a spring coil with turns, the friction torque is given by Equation (13): ...
Overrunning spring clutches are widely used as essential transmission devices, and the occurrence of abnormal noise can lead to a decline in their performance. This study investigates the dynamic aspects of abnormal noise in engineering applications, including its causes, influencing factors, and suppression methods. Audio processing algorithms are employed to analyze the audio associated with abnormal noise, and the Fourier Motion Blur algorithm is applied to process video images of the springs. By combining the motion blur curve with the noise spectrum curve, the source of the abnormal noise is identified as friction-induced vibrations in the spring. Theoretical modeling and calculations are carried out from a dynamic perspective to validate that the phenomenon of abnormal noise in the clutch is a result of self-excited friction vibration caused by the stick–slip phenomenon. Based on theoretical analysis and practical engineering, surface texturing is added to the center shaft of the spring seat, optimizing the system as an overdamped system to suppress self-vibration. Utilizing CFD simulation analysis, the simulation results are used to improve the texturing parameters and further optimize the texturing shape, resulting in an optimal parallelogram surface texture structure. Experimental validation confirms that the improved overrunning spring clutch completely eliminates abnormal noise during overrunning operation. Therefore, this paper contributes to the understanding of the dynamic issues associated with abnormal noise in overrunning spring clutches, confirming that the mechanism for abnormal noise generation is friction-induced self-excitation vibration, and demonstrating that surface texture optimization methods effectively suppress the occurrence of abnormal noise.
... Clutch friction torque manifests in both engagement and separation processes, mainly relying on changing the contact stress between the friction pair to transfer torque. The friction torque in the clutch engagement and separation processes is similar in the generation mechanism, and the friction torque model derived by Greenwood and Tripp will be cited below 29 . The force on the friction pair in operation is schematically shown in Fig. 5. ...
This paper aims to reduce friction pair erosion of the clutch in the case of continuous shift; the dynamic separation process of the friction pair is investigated. The temperature of the friction pair, friction torque, and separation speed in the separation process are taken as the research objects, and the dynamics simulation model and finite element thermal coupling simulation model of the clutch separation process are established. The nonlinear dynamic separation characteristics of the friction pair are investigated by comparing and analyzing the effects of control parameters such as rotational speed difference, damping ratio, and lubricant viscosity on the friction torque, friction pair separation speed, separation gap, and contact stress during the separation process. The gap recovery coefficient is proposed as a response indicator for observing the separation process in response to the inability to observe the nonlinear dynamic motion of the friction pair during the separation process and to measure the end time of the separation. Finally, the clutch was subjected to a separation test. The results show that the proposed gap recovery coefficient accurately describes the separation process. The simulation model can simulate the clutch's separation and predict the trend of separation parameters.
The non-linear stiffness actuator (NSA) is a kind of compliant joint with variable stiffness that is necessary for human-machine collaboration and has received extensive research attention. This academic work presents the principle of a torsion spring-connected non-linear stiffness actuator (TSNSA), a NSA suitable for implementing revolute motions, which contrasts with existing NSAs that often have bulky mechanisms and are affected by a limited range of movement. It has a split sleeve, disc springs and cam mechanisms (CMs) that when correctly configured, can passively and actively adjust stiffness, where the speed of stiffness regulation can be effectively improved. The mathematical model of a split sleeve inserted into a torsion spring is designed to analyze the behavior of mechanical components. Further, a detailed CM profile has been designed to obtain the desired non-linear stiffness. Its theoretical analysis includes numerical simulations with results that are consistent with the desired deflection-torque profile.
