Product Description:
Turntable bearing seat is a kind of large and extra-large bearing seat which can accept comprehensive load and special structure, and it has the characteristics of compact structure, sensitive rotation and convenient installation and maintenance. There are bearings where there should be a support point, the inner support point of the bearing is the shaft, the outer support is often referred to as the bearing housing.
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Name
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Pillow block ball bearings
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Function
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acceptance of combined load
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Type
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ball bearings with housing
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Insturction
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split bearing housing
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Classification
Meaning of bearing housing
Because a bearing can choose different bearing housings, and a bearing housings at the same time can be used for different types of bearings, therefore, bring a lot of varieties of bearing housings. Bearing housings are included in the catalogue, and many large foreign bearing companies also have their own bearing housings catalogue. But the same housing type in different companies samples are not exactly the same mark. For different applications of standard housings, you can choose different materials such as grey cast iron, nodular cast iron and cast steel, stainless steel, plastic special housings.
Bearing housings - Overview
According to the different requirements of the bearings and housings, the classification of the housings are not exactly the same, in the use of the time to be based on the design, carefully check the selection.
1 according to the shape of the bearing seat classification.
1.1 Outer spherical with housings bearings, also known as bearing units (SKF's words). Without bearing is called the external spherical bearing seat. 1.1.1.1 external spherical bearing seat its according to the series of bearings is divided into 200 series. 500 series. 300 series. 600 series. xoo series.
1.2 external spherical bearing seat according to the shape of the seat is divided into vertical seat (P seat), square seat (F seat), rhombus seat (FL seat), round seat (C seat), raised platform round seat (FC seat), raised platform square seat (FS seat), hidden hole seat (PA seat), hanging seat (FA seat).
1.3 Integral (i.e. non-separate) vertical housings with screw-fastened bearing caps. These vertical housing blocks were originally developed as axleboxes for light rail trucks, but can also be used for conventional vertical housing blocks. Non-separating vertical housings are more rigid than separating housings and some can carry heavier loads. External spherical bearing housings are also integral housings.
2 split bearing seat
2.1 Split bearing seat, according to the selection of different bearings and the requirements of the shaft into SN2, 5, 3, 6 series, SNL2, SNL5, SD has 2, 5, 3, 6, 3100, 3000, 3200[1].
Bearing housings are divided into: split bearing housings, sliding bearing housings, rolling bearing housings, bearing housings with flanges, external spherical bearing housings and so on.
Vertical
SNL Vertical Bearing Housing
Large SNL housings
SDG Vertical Housings
SONL Vertical Housing SAF Vertical Housing
SDAF Vertical Housing
Integral type
SBD Vertical Housing
TVN Vertical Housing
TN Vertical Housing
Flange
FNL Series Flanged Housings
7225(00) Series Flanged Housings
I-1200(00) Housings with Flanges
Turntable Structure
Slewing disc housings are a kind of large and extra-large housings that can accept comprehensive loads and have special structures, which are characterised by compact structures, sensitive rotation and easy maintenance of installations. Compared with ordinary bearing housings, turntable bearing housings have the following distinctive features.
1. External dimensions
The diameter is usually 0.4cm~10m, the maximum can reach 40m.
2. High bearing capacity
Ordinary can accept axial load, radial load and tilting moment load together.
3. Low rotational speed
The task rotational speed is lower than 10r/min, and a few conditions do not do continuous rotation, only in a certain angle of rotation, do swing motion.
4. With bearing housing device hole
It can be fastened to the upper and lower supports with screws.
5. No pivot axis
The inner ring or outer ring with rotary drive gear.
6. With smooth oil hole and sealing installation.
The important structure of the turntable bearing housing are: four-point contact ball turntable bearing housing, double-row angular contact thrust ball turntable bearing housing, interspersed cylindrical roller turntable bearing housing, interspersed tapered roller turntable bearing housing, three rows of cylindrical roller with turntable bearing housing.
According to whether or not with teeth and gear distribution parts are divided into: toothless, external teeth or internal teeth and other different structures.
Among them, four-point contact ball turntable bearing seat has high static bearing capacity, interspersed cylindrical roller turntable bearing seat has high dynamic bearing capacity, interspersed tapered roller turntable bearing seat can be applied through the preload to improve the support rigidity and rotary accuracy, and three rows of cylindrical roller with the turntable bearing seat to increase the height of the bearing seat in order to improve the load carrying capacity, the load discrimination of the different races to accept, therefore, in the same stress condition The diameter of the bearing housing can be greatly reduced, thus making the host more compact, is a kind of turntable bearing housing with high bearing capacity.
Slewing ring bearing housing is commonly used in lifting and transporting machinery, mining machinery, construction machinery, port machinery, ship machinery and high-precision radar and other large rotary installation.
Common problems-Wear and tear issues
Wear is the most common problem with bearing housings, and bearing housing wear occurs from time to time.
Repair Methods
The traditional method generally uses surfacing and then machining to repair, and surfacing will make the surface of the parts to reach a very high temperature, resulting in deformation of the parts or cracks, through machining to obtain the size of the downtime caused by a great extension of the time. The use of polymer composite materials for on-site repair, neither thermal impact, repair thickness is not limited, the wear resistance of the product and the metal material does not have the concessions to ensure that the repair part of the 100 per cent of the contact with the reduction of equipment shock vibration, to avoid the possibility of wear and tear. On-site repair, avoiding machining methods.
Repair process
Generally only four steps are required.
1. Surface treatment, the need to repair the surface of the bearing housing in addition to oil, in addition to moisture.
2. Mixing the repair material.
3. Apply the material, the material will be evenly coated in the bearing housing repair parts, filling solid;
4. Wait for the material to cure, can be appropriate to heat the material surface to accelerate the material curing.
General bearing chamber wear in 3-6 hours can be repaired, the operation is simple and easy to learn, without special equipment and special training, compared with laser welding, cold welding and other technologies to save time and effort, the cost is only 1/5-1/10 of the general repair costs, on-site repair is to reduce the equipment maintenance time and transport costs.
Examples
The bearing seat for a thermal power plant boiler workshop coal mill main drive reducer bearing seat, reducer transmission torque is large, in the process of long-term operation, Ⅰ shaft bearing chamber and bearing clearance between the outer ring, resulting in bearing chamber wear, wear uneven, the main wear parts are located in the upper cover of the gear box, the lower box body wear is lighter. The deepest depth of wear is about 2mm. Using polymer composite technology, the whole repair took 4 hours, plus the material curing time of 8 hours to complete all the repair work, to ensure the production of the enterprise. For the enterprise to save a lot of valuable time, and low cost.
Maintenance of bearing housing
Bearing housing in the use of the process of the following points to pay special attention to.
(1) the use of bearing housing cooling system. Bearing housing cooling water in the correct use of the case not only to extend the service life of the bearing housing, but also to improve productivity. Bearing housing materials are generally specialised bearing housing steel through a variety of treatments produced, and then the good bearing housing steel also have their limits of use, such as temperature. Bearing housings in use, if the mould temperature is too high, it is easy to make the core surface cracks appear early, some bearing housings have not even more than 2000 moulds cracks on a large area. Even bearing seat in the production because the bearing seat temperature is too high core have changed colour, after measurement even reached more than 400 degrees, such a temperature and then meet the release agent cold state is very easy to crack, the production of the product is also easy to deformation, strain, sticking to the mould and so on. In the case of using cooling water in the bearing housing can greatly reduce the use of release agent, so that operators will not use the release agent to reduce the temperature of the bearing housing. The benefit is to effectively extend the life of the bearing housing, save die casting cycle, improve product quality, reduce the occurrence of sticking mould and pulling and sticking aluminium, reduce the use of release agent. Can also reduce the bearing seat temperature overheating caused by the top rod and core loss.
(2) bearing seat in the beginning of the production process must be bearing seat preheating, to prevent in the cold bearing seat suddenly meet the hot metal liquid and lead to the emergence of cracks, the more complex bearing seat can be used with a blowtorch, liquefied gas, the conditions of the use of the mould temperature machine, the simpler bearing seat can be used to preheat the slow compression injection.
(3) on the bearing seat parting surface cleaning, this is very troublesome, but also very easy to ignore, the operator should be paraffin thoroughly on the bearing seat parting surface cleaning again, not only can prevent the bearing seat will not be extruded, but also after cleaning, can be on the bearing seat by the release agent residue or other dirt blocked exhaust groove through, is conducive to the process of compression injection of the cavity gas discharge to improve the quality of the product.
(4) if the bearing seat is equipped with neutron control, then pay attention to the absolute prohibition of die casting machine and the bearing seat between the signal line with the phenomenon of joints, the reason is very clear, in daily production, it is difficult to avoid the signal line stained with water, or joints wrapped place is easy to break, resulting in a short connection with the machine tool, if caused by the signal error, light is the alarm automatic shutdown delay, or heavy is the signal disorders, to the top of the bearing seat bad. Causing unnecessary losses. Travel switch attention to waterproof
Installation steps
Motor Bearing
I. Cleaning, Inspection and Insulation Board Requirements
1、 Cleaning and inspection of shaft tile
Large motor bearings are shipped in separate boxes, after opening the box, the first ring screws will be on the tile and the lower tile were taken out to mark and paraffin cleaning, dry with a dry cloth and check all grooves are clean, there is no casting residual sand, tungsten layer and the tile body is not a good combination of grooves, cracks exist in the trachoma and other adulteration, etc.). If it can not be repaired, it is necessary to re-hang tungsten gold.
2、 Bearing seat cleaning and inspection
Bearing seat should be cleaned and inspected before installation. The inner cavity of the bearing seat with a scraper to scrape away the dirt, with a cloth dipped in gasoline or solvent to wipe the dirt, to see if there is no cracks and holes in order to prevent oil seepage in operation. Bearing cover and bearing seat joint surface, bearing seat and bearing oil retaining ring joint surface should be research and scraping with, and check with a ruler, the gap shall not be greater than 0.03 mm. The surface of the base plate where the bearing seat is placed should also be cleaned up, and there should be no bruises, rust and burrs. Fasten the bearing seat screws and seat plate threads should be he carefully checked, and test screws to check whether too tight or bald buckle.
3、 Bearing insulation structure
Bearing and the base plate must be padded with insulating pads or metal shims, metal shims are used to adjust the horizontal position of the seat. To adjust the relative position of the motor and another motor or machinery connected. Metal shims are made of 0.08~3mm sheet metal. The insulating matting is made of fabric laminate or glass wire laminate. The purpose of placing insulating matting is mainly to prevent the hazards of shaft currents. The insulating mat board should be 5~10 mm wider than each side of the bearing seat and 3~10 mm thick. In addition to the bearing and the base plate placed between the insulating pads, while the screws and stable nails should also be insulated. Insulating washer with thickness of 2 ~ 5 mm glass cloth made of board, its outer diameter than the outer diameter of the iron washer 4 ~ 5 mm. With the bearing seat connected to the oil pipe catch plate insulating pad can be made of rubber plate with thickness of 1~2mm. Insulated bearing seat should be checked after installation of the insulation resistance to ground, measured with a 500-volt megohmmeter, the resistance value should not be less than 1 megohm.
II Installation
Both individual motor bearings and multiple bearings of the unit should be mounted on the main longitudinal axis of the machinery being coupled or on the longitudinal axis of the unit. Measurement of the bearing centre is checked by means of a hanging wire and a wire hammer. (A wooden strip is stuck inside the bearing arc and a thin iron bar is nailed in the centre of the strip to mark the centre position).
Adjustment of the position of the shaft in the seat is made by starting with the uppermost bearing seat and checking the level of these planes by placing a level on the face of the bearing seat. With the latitude and longitude or level to check the plane of several shaft seat is in the same level, and the use of wire hammer and other methods to find the centre of the bearings are in the same axis as shown in Figure 1-5.
According to the above method of adjustment of the bearing seat, to eliminate deviations in the process, should be used in the jack type tool to move the bearing seat, do not take the impact, hammering method. With this method to adjust the accuracy of the bearing seat error of about 0.5 ~ 1.0 mm. It should be noted that: the installation of the bearing seat adjustment is only pre-adjustment, in the centring also need to be adjusted to achieve the same requirements of the axis of the line. Bearing seat pre-adjustment, just the screws evenly tightened (according to the diagonal cycle of tightening), while the insulation sleeve and the steady nail can be temporarily not put, such as centring the final completion of the work or before the test drive and then put.
High temperature bearings
Since high temperature bearing housings must meet the requirements of both high precision stamping bearing housings and high temperature stamping bearing housings, the following two points need to be taken into account when considering the fit and clearance of high temperature bearing housings.
1, from room temperature to high temperature dimensional changes and hardness changes.
2, high-speed centrifugal force caused by the force system changes and shape changes.
High-temperature bearing seat requires the shaft and seat hole installation of stamping bearing seat parts should be higher than the general requirements of dimensional accuracy and form accuracy, especially coaxiality and shoulder on the seat hole or journal perpendicularity, it should be noted that, in considering these issues, must pay attention to the high-temperature bearing seat running high-speed factors and high-temperature factors.
Requirements for high-temperature bearing housing in the working state, that is, in the operating temperature has the best clearance, and this clearance is the inner and outer ring ball groove centre of the precise alignment of the formation of the state. At the same time, because the high temperature bearing housing seeks to reduce relative sliding and internal friction, so it is best not to use the inner and outer rings along the axial relative misalignment method to adjust the clearance of the high temperature bearing housing.
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