What should I do if the vibrating screen bearing is hot or damaged

SHANGHAI SHIBANG MACHINERY CO., LTD is one high-tech enterprise, which involves R&D, production, sales and service as well. In the past 20 years, we devote to producing mining equipments, sand making machines and industrial grinding mills, offering expressway, rail way and water conservancy projects the solution of making high grade sand and matched equipments.

What should I do if the vibrating screen bearing is hot or damaged?

Vibrating screen is a common equipment in mining machinery and equipment. The vibration is mainly generated by the exciter. The vibrator is in poor working condition and is subject to strong vibration shock, so the bearing will inevitably heat up. , burnout and other phenomena, seriously affect the normal operation of the vibrating screen.

According to the analysis of practical experience, the main causes of bearing damage are as follows:

First, the design reasons

    • 1, the bearing selection is not reasonable

The bearing type, the limit speed, the installation fit size, the clearance, the self-lubricating performance, etc. are relatively high, and the ordinary bearing is easy to be damaged under the severe working conditions. If the bearing is not properly selected at the beginning of the design, the bearing life will be shorter.

Solution: Use special bearings. Commonly used vibrating screen bearings generally have cylindrical roller bearings and spherical roller bearings. Both have large radial bearing capacity, the former is subject to higher limit speed, and has strong bearing capacity for dynamic and static loads, but has higher requirements on coaxiality of bearing housing holes; the latter has good self-aligning performance and can compensate Different shaft problems due to machining of the housing bore, but cannot withstand pure axial loads.

    • 2. The design of the lubrication seal structure is unreasonable.

At present, many vibration exciter bearings in China use grease lubrication and labyrinth seal structure, and the sealing gap is generally 1~2 mm. However, in actual use, as the temperature of the exciter bearing increases, the viscosity of the grease gradually decreases, the spindle rotates at a high speed, and the grease in the labyrinth cover leaks continuously from the labyrinth cover, eventually causing the bearing to be damaged due to lack of lubrication.

Due to the unreasonable design of the lubrication seal structure, the bearing lubrication is not sufficient, which is the main reason for the deformation of the bearing due to heat and burning.

Solution: Use thin oil lubrication to improve lubrication channels and improve sealing structure. Many manufacturers currently use thin oil circulation lubrication, and the structure of the labyrinth seal combined with other non-contact seals.

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    • 3, the bearing and the bearing housing hole are not properly selected

The tolerance between the bearing and the housing bore is the focus of the design. If a large interference fit is selected, the shape of the bearing race will be forced to deform geometrically and abnormally vibrate during operation. If a large clearance fit is selected, the outer ring of the bearing will slide relative to the bearing housing bore, causing the bearing to heat up and damage.

Solution: Choose a reasonable fit tolerance. The bearing inner ring and the shaft are matched with a loose transition fit or clearance fit tolerance, and the outer ring and the bearing housing bore adopt a tighter transition or a slightly smaller interference fit tolerance.

    • 4, the design does not consider the amount of expansion and contraction of the shaft

The operating temperature of the exciter is generally 35-60 ° C, and the amount of expansion and contraction of the shaft cannot be ignored due to thermal expansion and contraction.

Solution: Design one end bearing into a transition or clearance fit so that the exciter shaft can slide relative to the inner ring during thermal expansion and contraction.

Second, the process reasons

1. The machining accuracy of the bearing housing hole is not enough, and the bearing shaft holes of the same root shaft are different.

Solution: Using high-precision equipment, in the CNC boring and milling machine or machining center, the two bearing holes are cut at one time.

2. When the bearing is assembled, the force is uneven. For example, during the cold assembly process, the inner and outer rings of the bearing are not evenly biased, resulting in a certain amount of deflection between the inner and outer rings of the bearing relative to the shaft or the bearing hole, and the wear will be faster during the running process.

Solution: Use special tooling to make the inner ring or outer ring evenly pressed during the assembly process of the bearing and assembled in place.

3. The bearing is not cleaned when it is installed, or the lubricating oil is not clean, causing the bearing raceway to wear, the friction of the rolling element to increase, and the temperature to rise, causing the bearing to be damaged.

Solution: Clean the bearings before assembly. The vibration exciter is periodically replaced with a lubricant, and the first time the lubricant is changed after the equipment is used for 150 hours, and then replaced every 1000 hours.

4, the mass difference of the group of eccentric blocks, or the installation angle error of the group of eccentric blocks is large, causing the vibration source center to vibrate, resulting in bearing heat.

Solution: Adjust the mass and angle of the eccentric mass to make them symmetrical. When installing or adjusting the exciting force, the angle of the eccentric block on the same axis is the same, and the eccentric block on the parallel axis is angularly symmetrical.

Third, the reasons for use and maintenance

1. Due to the uneven foundation or the incorrect installation of the spring seat, the abnormal movement of the screen body is caused, causing the vibrating screen to rotate or twist, and the vibration of the vibration exciter bearing is damaged.

Solution: Adjust the base to make it level. When installing, first use the level to measure whether the foundation is level. If the unevenness can be adjusted by adding the pad on the basis.

2. The error of the center of gravity of the vibrating screen is large, causing the abnormal operation of the screen body, which causes the bearing heat to be damaged.

Solution: The ideal working condition of the vibrating screen is that the whole machine runs smoothly and the amplitudes are consistent everywhere. Therefore, it is necessary to strictly control the production and installation accuracy of the products, to ensure that the position of the center of gravity is not offset, and at the same time, as much as possible.

3. The vibration stirrer fixing bolt is loose, or the anti-loose spring washer is not added, causing the vibration source center to vibrate, resulting in damage to the bearing heat.

Solution: The shaker is used for the first time. After 2h and 50h, re-check the fastening bolts and find that the looseness is immediately tightened.

4. If the lubricating oil is improperly selected or filled too much or too little, it will cause the bearing to heat up.

Solution: Under normal circumstances, the lubricating oil should be filled with 2/3 of the lubrication chamber, too much heat, and must be exhausted with exhaust bolts. Generally, in the case of no oil leakage, the vibration device 80-100h is filled with lubricating oil once, the filling is not more than 1kg, and the waste oil is discharged in time.

The vibration exciter is the power source of the vibrating screen, which improves the design and processing quality. Correct use and careful maintenance are prerequisites for ensuring the good operation of the exciter bearing.

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