NEWS


30

2023

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08

9 details to help you analyze why rubber synchronous belt failure?

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There are many reasons for the failure of rubber synchronous belt. Usually, it is difficult to judge the failure mode of synchronous belt. Therefore, regular recording of the use of synchronous belt products is conducive to the failure of the late synchronous belt, there is a certain basis to judge which failure mode it belongs to, and it can be more targeted to choose appropriate preventive and corrective measures. We have sorted out the following nine cases that lead to the failure of the synchronous wheel:

1. Normal wear and failure of rubber timing belts due to long service life

When the service life of the core wire of the rubber synchronous wheel is reached, it is normal for the synchronous belt to fail at this time. After 2 to 3 years or even longer operation, the core wire is the failure caused by the service life reaching the limit, which belongs to the ideal failure mode of the synchronous belt. It is different from the failure mode of the tooth due to wear after long-term operation, which does not belong to the ideal failure mode of the synchronous belt.

The synchronous belt after 2 to 3 years of operation does not need to take any improvement measures. It will also be affected by various external objective factors due to the different life and application of its core wire. The factors affecting the life of the synchronous belt include transmission power level, environment, The installation tension of the synchronous belt, the matching of the belt and the wheel, the quality level of the pulley, and even how to cut, pack, transport and install the synchronous belt.

2. Rubber timing belt bending failure

The rubber synchronous belt has a very obvious performance due to the tortuous failure mode, that is, its fracture surface is arranged in a straight line.

This failure mode occurs when the rubber timing belt core is bent to a very small diameter. A sharp turn causes the core wire of the timing belt to bend and damage under huge pressure, which affects the tensile strength of the timing belt. This is the most common failure mode. This failure mode usually occurs due to improper operation of the timing belt and installation. The tension is too low, the diameter of the pulley is too small, and there are foreign objects in the pulley.

3. Low installation tension of rubber timing belt leads to failure

Too low installation tension will cause premature failure of the timing belt in the drive system of medium to high load. The failure mode of the installation tension is too low, and the common manifestation is the tooth jump. Jumping means that the teeth of the synchronous belt climb out of the corresponding groove range, and the root of the synchronous belt is no longer under load. The transmission load further acts on the side of the timing belt to deform the teeth of the timing belt, followed by jumping. In this case, the tooth jump will cause the rubber to tear from the tooth root along the core wire. At the same time, as the degree of rubber tearing increases, the timing belt teeth will start to separate from the timing belt in the form of strips. This failure mode is different from the failure mode caused by insufficient viscosity. For the failure mode caused by insufficient viscosity, the exposed core wire in the synchronous belt is relatively clean.

4. Failure caused by pulley quality

The production of pulleys does not meet the standards and the serious wear of pulleys will lead to premature failure of the timing belt, and the failure caused by these two reasons is very difficult to distinguish. The failure of the timing belt caused by the pulley is easy to be ignored, because the general timing belt fails, we will focus on the timing belt itself to investigate the cause. Due to the failure of the timing belt caused by the pulley problem, the side of the timing belt is generally fuzzy fluffy or flaky.

5. Pulley runout

The more the pulley jumps, the higher the maximum tension rises. When the pulley rotates, the tension of the timing belt will rise and fall periodically, when the timing belt runs in the radial runout pulley system. The bottom of the tooth will look like it has been crushed under the influence of the pulleys. The crushed belt body may be similar to the phenomenon caused by the excessive tension of the synchronous belt running in the moderate size pulley. The extreme periodic tension changes often lead to the tearing of the synchronous belt teeth or the tensile fracture of the synchronous belt. When the pulley is installed on the taper sleeve or reamed on the basis of the smallest light hole of the pulley, it is often prone to jump.

6. Failure caused by air corrosion

When the synchronous belt is applied to the foundry mixer, iron ore processing equipment, phosphate mining conveying equipment, it is easily affected by the corrosive air. Due to the failure caused by long-term use in an environment prone to corrosion and air corrosion, under normal circumstances, the wear of the belt tooth side and the bottom of the timing belt will be bright. The use of pulleys in corrosive air should increase the frequency of replacement of pulleys and timing belts, or adopt a sealed cover with clean air pressure, which can effectively prevent corrosive dust and impurities from entering the device.

7. Failure due to high temperature degradation

When the rubber synchronous belt is working in a high temperature environment higher than 85 ℃ for a long time, the rubber will harden due to the high temperature, and the back will be prone to cracking during operation. These cracks are usually parallel to the running direction of the teeth, and mostly occur in the middle of the teeth.

8. Chemical degradation leads to failure

The rubber timing belt in the environment of volatile organic solvents and ozone is similar to the above-mentioned failure caused by high temperature. It is also due to the hardening of the ingredients and the cracking of the back of the timing belt. However, the form of cracking is different, generally showing vertical and horizontal cracking, and even various shapes of cracking are possible.

9. Failure caused by foreign matter entering

Foreign matter between the pulley and the rubber timing belt will cause damage to the belt teeth and the core wire. Usually, in this case, the internal fox of the core wire is broken or excessive bending occurs soon after use and fails.