Personalized development of slewing bearings

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With the continuous development of construction machinery, according to the individual needs of users, the construction machinery is oriented towards the individual direction. For example, the excavator has large and medium-sized excavators, and various excavators for improving special purposes. Therefore, the requirements for the personalized development of slewing bearings are put forward. Today, the author mainly talks about the individualized development of slewing bearings.

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1. Individualized development of different sizes. Due to the inconsistency of various engineering machinery sizes and models, it is also necessary to adapt the size of the slewing bearing.

2. Special-purpose slewing bearings, such as the maximum bearing capacity, with the development of engineering machinery, toward the direction of large-scale development, some engineering machinery has hundreds of tons, so the maximum bearing capacity requirements of slewing bearings continue to increase.

3. Different temperature requirements, the mechanical application environment is now expanding, the total high temperature, high humidity, high salt environment and cold environment, the exhibition center is required to adapt.

4. Low failure rate requirements. With the development of aerospace technology, slewing bearings are required to have ultra-low failure rate characteristics.

In summary, with the development of engineering machinery, new requirements for slewing bearings have been put forward. The development of individualized engineering machinery requires the development of slewing bearings to meet the needs of construction machinery, and also the slewing bearing individualization. The driving force for development and the inevitable development.

Press roll bearing wear repair

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The press roll is the main component of the press. There are many types of press rolls. The press section of the old paper machine uses a flat press roll. With the increase of the speed of the paper machine, the vacuum press roll is used, and then the grooved press roll is developed. In the 1970s, the blind hole was researched and developed. Pressure roller and controllable medium and high roller.

After absorbing the advantages of the vacuum press roll, the grooved roll and the blind hole roll, several other new press rolls appeared. In the 1980s and 1990s, wide nip presses and shoe presses for high speed paper machines were developed. Until now, researchers have not stopped developing new press rolls. The purpose of developing new press rolls is to improve dewatering efficiency, improve the quality of the paper sheets, and reduce the adverse effects of the press on the paper industry.

 

Classification of press rolls:

Flat roll press

Both plain and positive presses are pressed with a flat roll. The structure of the flat roll press, the upper roll is a stone roll, the lower roll is a rubber roll, and both rolls have a smooth and smooth roll surface.

Stone rolls are a common flat press roll. Stone rolls are usually made of materials that are easily peeled off from paper, mostly using granite. The main feature of granite is that it has many tiny pores in its structure, which stores a certain amount of air, which is beneficial to the peeling of wet paper sheets. Its disadvantages are high cost and easy brittleness. During operation, if the rotation speed is too fast or the load is too large, the shaft head may be overheated, causing axial or annular cracks on the surface of the stone roller. When the high temperature expansion is serious, the shaft core may fall off.

With the increase in the speed of paper machines, the limitations of granite rolls are becoming more and more obvious. Most of today, artificial stone made of rubber and quartz sand is used instead of natural granite as the upper pressure roller.

The lower roll of the flat roll press is a rubberized cast iron roll. In addition to providing the corrosion resistance of the press roll, it is more important to provide good elasticity, to ease the pressing action of the upper press roll on the wet paper and the felt, thereby prolonging the life of the felt and reducing the “pressing” of the wet paper. The elastic under-sealing roller can also impart good contact and uniform dehydration between the two rolls and compensate for the high error in the lower press roll.

The rubber hardness of the rubber roller when producing general paper is usually 70 to 90 Shore hardness. The hardness of the rubber rollers used in each press of the press section increases as the pressure of each press line increases, and the hardness of the rubber roller also increases accordingly.