Abstract:

Objective This research aims to improve the long-lasting service and the reliability of the comber machine in cotton spinning. The mechanism of each part of the detaching roller at different velocities was analyzed to solve the problems caused by the fracture of the linkage parts of the detaching roller when working at a high velocity.

Method The first part of the research was focused on the dynamic simulations of the linkage gear of detaching roller based on the JSFA588 comber machine using a finite element (FE) analysis method. The three-dimensional (3-D) model of the linkage gear was established using SolidWorks software and then imported into Adams software. The curves of the force distribution of the linkage points at different velocities in a motion cycle were studied. The second part of this research concentrated on the FE analysis of the stress of each part of the linkage gear using Ansys Workbench software. The material properties of 45-carbon steel were assigned to the FE models and the maximum stress of each part at different velocities in a motion cycle was analyzed.

Results The change tendency of force in each part is the same in a motion cycle, but due to the existence of inertial force, the magnitude of force at the same index is different (Tab. 1). The peak force on each part increases with the speed of the comber machine (Tab. 2). The maximum stress of the eccentric sleeve was 66.565 MPa at 500 nippers/min (Fig. 4(a)); the maximum stress of the eccentric seat was 2.599 2 MPa ( Fig.4(b)); the maximum stress of the timing adjustment disc was 295.96 MPa (Fig. 4(c)); the maximum stress of the swing arm was 102.68 MPa, which is located at its lower end face (Fig. 4(d)); the maximum stress of linkage 2 was 38.667 MPa (Fig. 4(e)); the maximum stress of linkage 1 was 24.187 MPa (Fig. 4(f)); the maximum stress of the lower rocker, located at the round hole articulated with the linkage 1 was 4.718 7 MPa (Fig. 4(g)); and the maximum stress of the rocker was 101.62 MPa (Fig. 4(h)). All of the maximum stresses of the eccentric sleeve, eccentric seat, timing adjustment disc, swing arm, linkage gear 1, linkage gear 2, lower joystick and rocker were less than the allowable stress (400 MPa) in a motion cycle when the velocity of the comber was smaller than 500 nippers/min. The material strength of each part of the linkage gear of detaching roller was suitable for work. The maximum stress of the timing adjustment disc which was 415.98 MPa increased by 40.55% and 79.1%, respectively when the velocity of the comber was set to 600 nippers/min and 700 nippers/min compared to 500 nippers/min. The results showed that it has exceeded the allowable stress (400 MPa), which would lead to the fracture of each part of the linkage gear. Consequently, the comber machine was prone to be shut down. The tests were carried out according to the parametric requirements of the FE analysis on the JSFA588 comber machine, and the feasibility of the parameters was further verified (Tab. 6, Fig. 5 and Fig. 6).

Conclusion The influence of the device strength must be taken into account when the material property was confirmed. Conversely, in order to continue to increase the velocity of the comber machine, it is necessary to balance the influence of the material properties of each part and the cost.

Key words: comber machine, detaching roller linkage drive mechanism, hinge point force, part strength, kinetic simulation, finite element analysis