The meaning of bearing seat
Since a bearing can choose different bearing seats, and a bearing seat can choose different types of bearings at the same time, there are many varieties of bearing seats. The bearing seat is include in Quick and Easy, and many large foreign bearing companies also have their own bearing seat catalogs. However, the same bearing housing model is not identically mark in different company catalogs. For different applications of standard bearing housings, housings of different materials can be select such as: grey cast iron iron, ductile iron and special bearing housings of cast steel, stainless steel and plastic.
Bearing Housings – Overview
According to the different requirements of the bearing and the bearing seat, the classification of the bearing seat is not exactly the same. When using, it should be carefully checked and select according to the design.
1 According to the shape of the bearing seat:
1.1 Outer spherical bearing with seat, also known as bearing unit (SKF parlance). When there is no bearing, it is call an outer spherical bearing seat. 1.1.1.1 The outer spherical bearing seat is divide into 200 series according to the series of bearings. 500 series. 300 series. 600 series. XOO series.
1.2 The outer spherical bearing seat is divide into vertical seat (P seat), square seat (F seat), diamond seat (FL seat), circular seat (C seat), boss round seat (FC seat), convex seat Taiwan square seat (FS seat), dark hole seat (PA seat), hanging seat (FA seat).
1.3 Integral (ie non-separable) vertical bearing block housing with screw-fastened bearing housing cover. These plummer block housings were originally developed as axleboxes for light rail trucks, but can also be use with conventional plummer blocks. Non-separable plummer block housings are more rigid than separate housings, and some can handle heavier loads. The outer spherical bearing seat also belongs to the integral seat.
2-split housing
2.1 Split bearing seat, according to the different bearings and shaft requirements, it is divide into SN2, 5, 3, 6 series, SNL2, SNL5, SD are 2, 5, 3, 6, 3100, 3000, 3200
The bearing seat is divide into: split bearing seat, sliding bearing seat, rolling bearing seat, bearing seat with flange, outer spherical bearing seat, etc.
vertical
Large SNL housing
SDG vertical bearing housing
SONL Plummer Block SAF Plumb Block
SDAF plummer housing
Integral
SBD vertical bearing housing
TVN vertical bearing housing
TN vertical bearing housing
flange
FNL series flange bearing seat 7225 (00) series flange bearing seat
I-1200(00) bearing housing with flange
Bearing Housing FAQ
wear problem
Wear is the most common problem in bearing housings, and bearing housing wear also occurs frequently.
Repair method
The traditional method is generally repair by machining after surfacing, and surfacing will make the surface of the component reach a high temperature, causing deformation or cracking of the component, and obtaining the size through machining will greatly extend the downtime. The use of polymer composite materials for on-site repairs has neither thermal influence nor limited repair thickness. The wear resistance of the product and the concessionality that metal materials do not have, ensure 100% contact and cooperation of the repaired parts and reduce equipment costs. shock and vibration to avoid the possibility of wear. On-site repair, methods that avoid machining.
Repair process
Generally only four steps are require:
1. Surface treatment, the bearing housing surface will need to be repair to remove oil and moisture;
2. Reconcile repair materials;
3. Apply the material, apply the material evenly to the repair part of the bearing seat, and fill it firmly;
4. Wait for the material to solidify, and heat the surface of the material appropriately to accelerate the solidification of the material.
The general bearing chamber wear can be repaired in 3-6 hours. The operation is simple and easy to learn, and no special equipment and special training are required. Compared with laser welding, cold welding and other technologies, it saves time and effort, and the cost is only 1/5- of the general repair cost. 1/10, on-site repair reduces equipment maintenance time and transportation costs.
for example
The bearing seat is the bearing seat of the main drive reducer of the coal mill in a boiler workshop of a thermal power plant. The reducer transmits a large torque. During the long-term operation, there is a gap between the bearing chamber of the I-axis and the outer ring of the bearing, which causes the bearing chamber to wear. The wear is uneven, the main wear part is located on the upper cover of the gear box, and the lower box body wears less. The deepest depth of wear is about 2mm. Using the polymer composite material technology, the whole repair work takes 4 hours, and the material curing time is 8 hours to complete the whole repair work, which ensures the production of the enterprise. Save a lot of valuable time for the business, and the cost is low.
Maintenance and maintenance of bearing housings
The following points should be paid special attention to during the use of the bearing seat:
- The use of the bearing housing cooling system. When used correctly, the bearing housing cooling water not only prolongs the service life of the bearing housing, but also improves the production efficiency. The material of the bearing seat is generally made of special bearing seat steel through various treatments, and the best bearing seat steel also has the limit of their use, such as temperature.
When the bearing seat is in use, if the mold temperature is too high, it is easy to cause early cracks on the surface of the mold core, and some bearing seats have not even exceeded 2000 mold times. Even in the production of the bearing seat, because the temperature of the bearing seat is too high, the mold core has changed color. After measurement, it even reached more than 400 degrees.
When such a temperature encounters the release agent chilled, it is easy to have cracks. The products are also prone to deformation, strain, sticking, etc. The use of mold release agent can be greatly reduced in the case of using the cooling water of the bearing seat, so that the operator will not use the mold release agent to reduce the temperature of the bearing seat. The advantage is to effectively prolong the life of the bearing seat, save the die-casting cycle, improve the product quality, reduce the occurrence of mold sticking, strain and aluminum sticking, and reduce the use of mold release agents. It can also reduce the loss of the ejector pin and core due to overheating of the bearing seat.
- The bearing seat must be preheated in the process of starting production to prevent the occurrence of cracks caused by the sudden encounter of hot metal liquid in the cold bearing seat. The more complicated bearing seat can be liquefied with a blowtorch. The mold temperature machine is used in good conditions, and the relatively simple bearing seat can be preheated by slow injection.
- Cleaning the parting surface of the bearing seat is very troublesome and easy to ignore. The operator should use kerosene to thoroughly clean the parting surface of the bearing seat, which can not only prevent the bearing seat from being crushed, but also Moreover, after cleaning, the exhaust groove on the bearing seat blocked by the residue of the mold release agent or other dirt can be opened, which is beneficial to the discharge of the gas in the cavity during the injection process and improves the product quality.
- If the bearing seat is equipped with neutron control, it is absolutely forbidden to have joints on the signal line between the die-casting machine and the bearing seat. The reason is very clear. In daily production, it is difficult to avoid water on the signal line, or The place where the joint is wrapped is easy to break, resulting in a short circuit with the machine tool. If the signal is wrong, the alarm will automatically stop and delay the time, and the signal will be disordered and the bearing seat will be damaged. cause unnecessary losses. Travel switch pay attention to waterproof
Bearing housing installation steps
Motor bearing
Requirements for cleaning, inspection and insulating pads
1. Cleaning and inspection of bearing bushes
The bearings of large motors are shipped separately. After unpacking, take out the upper tile and the lower tile with lifting ring screws and make a mark and clean them with kerosene. Dry them with a dry cloth and check whether all the grooves are clean and whether there is any residual sand in the casting. , the tungsten gold layer is not well combined with the tile body, and there are sand holes and other dopants in the drawn channels and cracks). If it cannot be repaired, tungsten gold should be re-mounted.
2. Cleaning and inspection of bearing seat
Before the bearing seat is installed, it should also be thoroughly cleaned and inspected. Scrape off the dirt in the inner cavity of the bearing housing with a scraper, wipe the dirt with a cloth dipped in gasoline or solvent, and check for cracks and blisters to prevent oil leakage during operation. The joint surface of the bearing cover and the bearing seat, the joint surface of the bearing seat and the bearing oil retaining ring should be ground and scraped, and checked with a feeler gauge, and the gap should not be greater than 0.03 mm. The surface of the bottom plate on which the bearing seat is placed should also be cleaned, and there should be no bumps, rust and burrs. The screws that fasten the bearing seat and the thread of the seat plate should be carefully checked by him, and try to tighten the screws to check whether they are too tight or bald.
3. Bearing insulation structure
An insulating pad or metal shim must be placed between the bearing and the bottom plate, and the metal shim is used to adjust the horizontal position of the seat. To adjust the relative position of the motor and another connected motor or machine. The metal spacer is made of metal sheet of 0.08~3mm. Insulation pads are made of cloth laminate or fiberglass laminate. The purpose of placing the insulating pad is mainly to prevent the harm of shaft current.
The insulating pad should be 5~10mm wider than each side of the bearing housing, and the thickness should be 3~10mm. In addition to placing an insulating pad between the bearing and the base plate, the screws and studs should also be insulated. The insulating gasket is made of glass fiber cloth with a thickness of 2~5 mm, and its outer diameter is 4~5 mm larger than the outer diameter of the iron washer.
The insulating pad of the oil pipe connecting plate connected to the bearing seat can be made of rubber sheet with a thickness of 1~2 mm. After the insulated bearing seat is installed, the insulation resistance to ground should be checked and measured with a 500-volt megohmmeter, and its resistance should not be less than 1 megohm.
Two installation
Both the single motor bearing and the multi-bearing of the unit should be installed on the main longitudinal axis of the connected machine or the longitudinal axis of the unit. The bearing center is measured by hanging wire and wire hammer. (Clip a wooden strip in the bearing arc, and nail a thin iron strip in the center of the wooden strip to mark the center position).
To adjust the position of the shaft on the seat, start from the bearing seat on the farthest side, and use a spirit level on the bearing seat surface to check the levelness of these planes. Use a theodolite or a spirit level to check whether the planes of several axle seats are in the same horizontal plane, and use a wire hammer to find out whether the center of each bearing is on the same axis.
Adjust the bearing seat according to the above method. During the process of eliminating deviation, use a jack-type tool to move the bearing seat, and do not use the method of impact and hammering. The accuracy error of adjusting the bearing seat with this method is about 0.5~1.0 mm. It should be pointed out that the installation adjustment of the bearing seat is only a pre-adjustment, and it is also necessary to adjust the centering to meet the requirements of the consistent axis line. After the bearing seat is pre-adjusted, just tighten the screws evenly (tighten in a diagonal cycle), while the insulating sleeve and the stabilizer can be left temporarily until the centering work is finally completed or before the test run.
High temperature bearing
Since the high-temperature bearing housing must meet the requirements of high-precision stamped bearing housings and high-temperature stamped bearing housings, the following two points need to be considered when considering the fit and clearance of high-temperature bearing housings:
1. Dimensional change and hardness change from normal temperature to high temperature;
2. Force system change and shape change caused by centrifugal force at high speed.
The high temperature bearing seat requires the shaft and the seat hole to install the stamped bearing seat to have higher dimensional accuracy and shape and position accuracy than the general requirements, especially the coaxiality and the verticality of the shoulder to the seat hole or journal. It should be noted that , When considering these issues, attention must be paid to the high-speed factor and high-temperature factor during the operation of the high-temperature bearing seat.
It is required that the high-temperature bearing seat has the best clearance under the working condition, that is, at the working temperature, and this clearance is formed under the condition that the centers of the inner and outer ring ball grooves are precisely aligned.
At the same time, since the high temperature bearing seat strives to reduce relative sliding and internal friction, it is best not to adjust the clearance of the high temperature bearing seat by dislocating the inner and outer rings relative to each other in the axial direction.
