How can the main shaft bearing of a mine hoist withstand the weight of a thousand tons

One The main function of the main shaft bearing of the mine hoist

The main shaft bearing of a mine hoist plays a crucial role in the operation of the hoist. It not only provides support for the main shaft, reduces friction and wear, and bears loads, but also ensures the rotational accuracy of the main shaft. It is one of the key components to ensure the safe and efficient operation of the hoist.

1. Support the spindle

The spindle is the core component of the mine hoist, which bears the maximum twisting and bending loads during start-up and operation. The spindle bearing provides stable support for the spindle, ensuring that it maintains the correct position and geometric accuracy under high-speed rotation and heavy loads.

2. Reduce friction and wear

The spindle will generate friction with surrounding components during rotation. The spindle bearing can effectively reduce frictional resistance and improve the mechanical efficiency of the hoist.

3. Load bearing capacity

Radial load: During the operation of the mine hoist, the main shaft will be subjected to radial loads from components such as the lifting container and steel wire rope. The main shaft bearing can withstand these radial loads and evenly distribute them onto the bearing seat, avoiding local overload.

Axial load: In addition to radial load, the main shaft is also subjected to axial load, such as the inertial force generated by the elevator during start-up, braking, or in case of emergencies. The main shaft bearing can withstand a certain axial load and ensure the stability of the main shaft in the axial direction.

4. Ensure rotational accuracy

Radial runout control: The accuracy and installation quality of the spindle bearings directly affect the rotational accuracy of the spindle. High precision spindle bearings can limit the radial runout of the spindle, ensuring smooth lifting and lowering of the lifting container during operation, reducing vibration and noise.

Axial movement control: The spindle bearing can also control the axial movement of the spindle, preventing excessive movement of the spindle in the axial direction. Excessive axial movement can affect the braking effect and safety performance of the hoist.

II Analysis of the causes of damage to the main shaft bearings of mine hoists

1. Installation issues

Inaccurate alignment during installation is a common issue.

The axis of the main shaft of the hoist is not aligned with the axis of the reducer shaft or motor shaft, which will cause the bearings to bear additional radial and axial loads, thereby reducing the service life of the bearings.

2. Poor lubrication

The selected lubricating oil has an inappropriate viscosity, substandard quality, or is not suitable for specific working environments.

Too much oil can cause waste and poor heat dissipation, while too little oil cannot provide sufficient lubrication.

3. Poor working environment

The mining environment is harsh, with a large amount of dust and impurities present. These substances enter the interior of the bearings, damaging the lubricating film and increasing the friction coefficient of the bearings, thereby accelerating their wear.

The temperature and humidity in the mine are high, and high temperatures can reduce the viscosity of lubricating oil, affecting the lubrication effect; Meanwhile, high temperatures can also cause a decrease in the material strength of bearings, making them prone to deformation and damage.

4. Overload and impact loads

If the hoist is frequently overloaded during operation, it will cause the main bearings to bear excessive loads, exceeding their carrying capacity. Long term overload operation can lead to bearing fatigue damage, cracking, peeling, and other phenomena.

Elevators may experience significant impact loads during startup, braking, or in the event of unexpected situations. These impact loads can instantly subject the bearings to enormous stress, which can easily lead to bearing damage. For example, during emergency braking of a hoist, the inertia force will cause the bearings to bear a large axial load, resulting in severe impact on the bearings.

5. Inadequate maintenance and upkeep

If the main bearings of the hoist are not regularly inspected, problems such as wear, cracks, looseness, etc. cannot be detected in a timely manner. If these problems are not dealt with in a timely manner, they will gradually deteriorate and ultimately lead to bearing damage.

When abnormal conditions are found in the bearings, if maintenance and repair are not carried out in a timely manner, the problem will also worsen. For example, when the bearing temperature is found to be too high, the noise increases, or the vibration is abnormal, the machine should be stopped immediately for inspection, and the cause should be identified and dealt with. If maintenance time is delayed, it may cause more severe bearing damage and even trigger other malfunctions.

III Method for replacing the main shaft bearing of mine hoist

1. Construction preparation

Due to the need for continuous operation, sufficient lighting is ensured in the winch room;

Prepare welding machine, gas belt, oxygen, acetylene, goggles, etc;

According to the on-site situation, process the I-beams according to the quantity and material requirements;

Measure the air gap between the motor rotor and stator in advance to determine the maximum lifting height of the friction wheel;

Detach the four steel wire ropes and fix them in place with a rope locking device; Remove the disc brake device, friction wheel cover, non transmission side encoder connection device, and upper end caps of the left and right bearing seats.

2. Lift up the friction wheel and main shaft

Thread two specially made I-beams through the manhole in the middle of the friction wheel roller, and use I-beams to build a jack base directly below the I-beams. Use jacks to support both ends of the I-beams, with the top end of the jack piston rod just touching the I-beams. Lift up four jacks at the same time to provide sufficient clearance on both sides of the bearings for disassembly and installation.

3. Removal of old bearings

Measure the average clearance of old bearings using a feeler gauge and record and save it;

Mark the installation position of the old bearing for reference when installing the new bearing;

Use a high-pressure oil pump to inject pressure oil through the oil injection hole at the shaft end. When the pressure gauge shows around 10 Mpa, slow down the compression speed to enlarge the inner hole and form a pressure oil film on the joint surface. When you hear the friction sound between the bearing inner ring and the main shaft, use a jack to remove the old bearing.

4. Installation of new bearings

Use far-infrared heaters to evenly heat the bearings on the transmission and non transmission sides to 130 ℃, and install the bearings on both ends.

Use pre prepared fixtures to limit the newly installed bearings.

After the newly installed bearings have cooled to room temperature, measure the installation position and average clearance of the bearings again. The lifting system can only be restored when the bearing clearance is within the allowable range.

The main shaft bearing of the mine hoist, which is not usually a highly concerned component, actually carries the "weight of life" of the hoist. It not only provides solid support for the spindle, reducing friction and wear, but also plays a key role in bearing various loads and ensuring rotational accuracy.

Improper installation, poor lubrication, harsh working environment, overload impact, and inadequate maintenance are all the "culprits" that lead to its damage. Every detail is crucial, and even a slight negligence can trigger a chain reaction, leading to bearing damage and even affecting the operation of the entire hoist.

We don't need to panic when facing bearing damage. By mastering the correct replacement method, one can easily cope with it. From construction preparation to lifting the friction wheel and main shaft, to dismantling old bearings and installing new bearings, every step requires careful planning and meticulous operation. Using special I-beams, jacks, high-pressure oil pumps and other tools, combined with precise measurement and limit fixtures, to ensure that the new bearings are installed in place and have moderate clearance.

The maintenance and replacement of the main shaft bearings of mine hoists is not only a test of technology, but also an interpretation of responsibility and commitment. Only by deeply understanding its function, causes of damage, and replacement methods can we ensure the safe and efficient operation of the hoist, and safeguard the production of the mine.