Creep characteristics of knitting machine belts under long-term load and their impact on knitting machine precision
Publish Time: 2025-05-13
As a key component of the knitting machine transmission system, the performance of knitting machine belts directly affects the operating stability and product precision of the equipment. Under long-term load, polyurethane materials will inevitably creep, that is, the material slowly deforms under continuous stress, resulting in gradual changes in the length, tension and tooth structure of the synchronous belt. This microscopic deformation accumulation will further affect the transmission accuracy of the knitting machine, and even cause fabric defects or equipment failures. Therefore, in-depth understanding of the creep characteristics of knitting machine belts and their impact on knitting machines is of great significance for optimizing equipment maintenance strategies and improving production efficiency.Polyurethane materials are widely used in synchronous belt manufacturing due to their excellent wear resistance, high elasticity and fatigue resistance. However, as a high molecular polymer, the molecular chain of polyurethane will slip and rearrange under long-term stress, which manifests as macroscopic creep behavior. During the continuous operation of the knitting machine, the synchronous belt needs to withstand periodic tension and friction, especially under high-speed or high-load conditions, the creep effect is more significant. As time goes by, the initial preload of the synchronous belt gradually decays, resulting in an increase in the meshing gap between the belt and the pulley, and the phenomenon of tooth skipping or slipping may occur during the transmission process. This transmission instability will be directly transmitted to the needle bed movement of the knitting machine, causing quality problems such as uneven needle spacing and inconsistent coil length, which seriously affect the appearance and physical properties of the fabric.The influence of creep on the precision of the knitting machine is mainly reflected in the dynamic response of the transmission system. As a medium for precision transmission, the deformation of the synchronous belt will destroy the originally designed motion trajectory. For example, in a jacquard knitting machine, the needle bed needs to perform high-frequency reciprocating motion strictly according to the program. If the synchronous belt is slightly elongated due to creep, it will cause the needle bed position to lag or advance, causing the hooking action of the knitting needle to deviate from the coordination of the yarn guide. This deviation may manifest as problems such as misalignment of the fabric pattern, missed needles or uneven yarn tension. In addition, creep may also increase the wear rate of the synchronous belt, especially the stress concentration area at the root of the tooth, further shortening the service life. When the deformation of the synchronous belt exceeds the design tolerance, it cannot be fully compensated even by adjusting the tension. At this time, the synchronous belt must be replaced to avoid more serious equipment damage.In order to alleviate the negative impact of creep on the precision of knitting machines, it is necessary to start from material selection, structural design and maintenance management. In terms of materials, the creep resistance of polyurethane can be improved by adding reinforcing fibers or nanofillers to delay the slip process of molecular chains. In terms of structural design, optimizing the tooth profile and belt thickness distribution helps to evenly disperse stress and reduce local deformation. For example, the use of arc-shaped tooth design can reduce the stress concentration at the root of the tooth, while the high modulus backing layer can inhibit the longitudinal elongation of the belt. In addition, a reasonable initial tension setting is also crucial. Too high tension will accelerate creep, while too low tension will easily cause slippage, and it needs to be dynamically adjusted according to the equipment load.In actual production, regular monitoring of the tension change and wear state of the synchronous belt is an effective means to prevent precision loss. Through infrared thermal imaging or vibration analysis technology, abnormal deformation or local overheating of the synchronous belt can be detected early, and maintenance measures can be taken in time. At the same time, a preventive replacement system based on running time should be established to avoid sudden failures caused by excessive aging of the synchronous belt. For high-precision knitting machines, a closed-loop feedback system can also be considered to compensate for the transmission error caused by creep in real time to ensure the accuracy of the needle bed movement.In summary, the creep characteristics of knitting machine belts are the key factors affecting the long-term operation accuracy of knitting machines. Through the comprehensive means of material improvement, structural optimization and scientific maintenance, the negative impact of creep can be significantly reduced, the service life of the synchronous belt can be extended, and the quality stability of knitting products can be guaranteed. In the future, with the advancement of polymer material technology and the popularization of intelligent monitoring systems, the application potential of knitting machine belts in high-speed and high-precision knitting machines will be further released.
