08.26.2024
Introduction to the properties, working principles and performance of deep groove ball bearings
Deep groove ball bearings (GB/T 276-2003), originally listed as radial ball bearings, are the most widely used type of rolling bearing.It is characterized by low frictional resistance and high speed, and can be used on parts that bear radial loads or combined loads acting simultaneously in both the radial and axial directions. It can also be used on parts that bear axial loads, such as small-power motors, automotive and tractor transmissions, machine tool gearboxes, general machines, tools, etc.
Nature
Deep groove ball bearings are the most common type of rolling bearing.
Deep groove ball bearings
The basic deep groove ball bearing consists of an outer ring, an inner ring, a set of steel balls and a retainer.Deep groove ball bearings are available in single-row and double-row designs. The deep groove ball structure is further categorized into sealed and open types. Open type refers to bearings without a sealing mechanism, while sealed deep groove balls are divided into dustproof seals and oil-resistant seals.The dust-proof sealing cover is made of steel plate stamping, which only plays a simple role in preventing dust from entering the bearing raceway.The oil-proof type is a contact oil seal, which can effectively prevent the lubricating grease in the bearing from overflowing.
The type code for single-row deep groove ball bearings is 6, and the type code for double-row deep groove ball bearings is 4.It is a simple structure and easy to use, making it the most common and widely used type of bearing in production.
Working principle
Deep groove ball bearings mainly withstand radial loads, and can also simultaneously withstand both radial and axial loads.When it is subjected to radial load only, the contact angle is zero.When the deep groove ball bearing has a large radial clearance, it has the performance of an angular contact bearing and can withstand high axial loads. The friction coefficient of the deep groove ball bearing is very small and its limit speed is also very high.
Bearing characteristics
Deep groove ball bearings are the most commonly used rolling bearings.Its structure is simple and easy to use.It is mainly used to withstand radial loads, but when the bearing's radial clearance is increased, it has some of the performance of angular contact ball bearings and can withstand combined radial and axial loads.When the speed is high and it is not suitable to use thrust ball bearings, it can also be used to withstand pure axial loads.Compared with other types of bearings having the same specifications and dimensions as deep groove ball bearings, this type of bearing has a small friction coefficient and high limit speed.However, it is not resistant to impact and unsuitable for heavy loads. [2]
After the deep groove ball bearing is installed on the shaft, it can limit the axial displacement of both directions of the shaft or housing within the range of its axial clearance. Therefore, it can be used for bidirectional axial positioning.In addition, this type of bearing also has a certain self-aligning ability. When tilted by 2' to 10' relative to the housing hole, it can still work normally, but there is some impact on the life of the bearing.
Structure and classification
Bearing structure
Deep groove ball bearings have a simple structure and are easier to achieve high manufacturing accuracy compared with other types, so they are easy to mass produce in series. The manufacturing cost is also low and the use is extremely common.In addition to the basic type, there are various modified structures of deep groove ball bearings, such as deep groove ball bearings with dust covers, deep groove ball bearings with rubber seals, deep groove ball bearings with stop grooves, deep groove ball bearings with large load capacity and ball installation gaps, and double-row deep groove ball bearings.
Bearing type
Deep groove ball bearings are mainly used to withstand radial loads, but they are also often used to withstand combined radial and axial loads.Especially when the speed of mechanical equipment is very high and thrust bearings are not suitable, this bearing can be used to withstand bidirectional pure axial loads without maintenance during operation. It is a low-cost, widely used type of bearing.Deep groove ball bearing models include: deep groove ball bearings (60000 type);Deep groove ball bearing with stopper slot on the outer ring (60000N type);Deep groove ball bearing (60000-ZN type) with dust cover on one side and stopper groove on the outer ring of the other side;Deep groove ball bearing with dust cover on both sides and stopper slot in the outer ring (60000-2ZN type);Deep groove ball bearing with dust cover on one side (60000Z type);Deep groove ball bearing with dust cover on both sides (60000-2Z type);Deep groove ball bearings with seal rings (60000-LS type, 60000-RZ type);Deep groove ball bearings with sealing rings on both sides (60000-2LS type, 60000-2RZ type);Flange outer ring deep groove ball bearing (F60000 type);One flange outer ring deep groove ball bearing with dust cover (F60000-Z type);There are 11 types of deep groove ball bearings (F60000-2Z type) with flanges on both sides and dust covers.
According to the size of deep groove ball bearings, they can be divided into:
(1) Miniature bearings - bearings with a nominal outer diameter size range of less than 26mm;
(2) Small bearing - the nominal outer diameter size range is 28-55mm;
(3) Small and medium-sized bearings - bearing with a nominal outer diameter ranging from 60 to 115mm;
(4) Medium and large bearings - bearing with a nominal outer diameter ranging from 120 to 190mm
(5) Large bearings - bearings with a nominal outer diameter ranging from 200-430mm;
(6) Extra-large bearing - a bearing with a nominal outer diameter size range of 440mm or more.
Processing form
The processing forms of deep groove ball bearing parts are as follows:
Multi-process machining: Generally, bearing production requires 20 to 40 processes, with up to more than 70.
2. Molding process: The working surfaces of bearing parts are all rotary molding surfaces, which are suitable for processing using the molding method.
3. Precision machining: Most of the surfaces of bearing parts are subjected to grinding, and the dimensions and geometric accuracy of the grinding process are measured in micrometers (μm).
Usage Application
Deep groove ball bearings can be used in gearboxes, instruments and meters, motors, household appliances, internal combustion engines, transportation vehicles, agricultural machinery, construction machinery, engineering machinery, roller skates, yo-yos, etc
Installation method
Deep groove ball bearing installation method 1: Press-fit: When the inner ring of the bearing is tightly fitted to the shaft and the outer ring is loosely fitted to the bearing seat hole, a press can be used to first press fit the bearing onto the shaft. Then, the shaft along with the bearing should be installed into the bearing seat hole. During this process, a soft metal material (such as copper or mild steel) should be placed on the end face of the inner ring of the bearing for assembly purposes. If the outer ring of the bearing fits tightly to the bearing seat hole while the inner ring has a loose fit with the shaft, the bearing can be pressed into the bearing seat hole first. At this point, the outside diameter of the assembly sleeve should be slightly smaller than that of the seat holeIf the bearing ring is tightly fitted with both the shaft and the seat hole, the inner and outer rings should be pressed into the shaft and seat hole simultaneously. The assembly sleeve structure should be able to compress the end faces of the inner and outer rings of the bearing at the same time.
Deep groove ball bearing installation method 2: heating fit: an installation method that uses heat expansion to convert a tight fit into a loose fit by heating the bearing or bearing housingIt is a common and labor-saving installation methodThis method is suitable for the installation of bearings with large interference. Before hot assembly, place the bearing or separable bearing ring in an oil tank and heat it evenly at 80-100℃. Then remove it from the oil and install it on the shaft as soon as possible. To prevent the inner ring end face and shaft shoulder from not fitting tightly after cooling, axial tightening can be performed again after the bearing cools downWhen the outer ring of bearing is tightly fitted with light metal bearing seat, the hot charging method for heating the bearing seat can be used to avoid scratching on the fitting surface.When heating the bearing with an oil tank, there should be a mesh grid at a certain distance from the bottom of the tank. Alternatively, use hooks to suspend the bearing so that it cannot rest on the bottom of the tank. This prevents foreign matter from entering the bearing or uneven heating. The oil tank must have a thermometer and strictly control the temperature not exceeding 100℃ to prevent backfire effects and reduce the hardness of the ring.
tolerance
The standard deep groove ball bearings are of ordinary grade and all comply with GB/T 307.3-1996.
Clearance
The radial clearance of the bearing is divided into original clearance, installation clearance and working clearance.Generally, the original radial clearance of a bearing is greater than its working clearance.Clearance is an important technical parameter of bearings, which directly affects the bearing's load distribution, vibration, noise, friction, service life and mechanical motion accuracy.Strictly speaking, the rated dynamic load of a bearing varies with the size of its clearance.The rated loads (C and C0) listed in the product sample are load values when the working clearance is zero.Excessive clearance can lead to a reduction in the load-bearing area within the bearing, an increase in rolling contact surface stress, a decrease in the accuracy of the bearing's motion, increased vibration and noise, and a shortened service life of the bearing. If the clearance is too small, it can cause heating and temperature rise, and even lead to "seizure" during operation.Therefore, it is important to select different grades of bearing clearance according to the type and working conditions of the bearings.
Radial clearance table of deep groove ball bearings
Standard deep groove ball bearings have internal clearances of C2, standard (CN), C3, C4 and C5 grades, all in accordance with GB4604.The radial clearance of deep groove ball bearings is shown in the following table
Keep the shelf
Deep groove ball bearings generally use steel plate stamped cages or brass solid cages.When the outer diameter is less than 400 mm, a steel plate stamped cage without post-code is used. When the outer diameter exceeds 400 mm, a brass solid cage without post-code is preferred.
Matters needing attention
In the operation of deep groove ball bearings, if the bearing load is too small, it can cause slippage between the balls and raceways, leading to scratches.This tendency is especially pronounced in large deep groove ball bearings with heavy balls and cages.In many cases, bearings will rust. There are many reasons for bearing corrosion, and the most common ones in our daily life include:
1) Due to poor sealing, it is invaded by moisture and dirt;
2) The bearing is not used for a long time, exceeding the rust prevention period and lacking maintenance.
3) The metal surface roughness is large;
4) Contact with corrosive chemical media, the bearing is not cleaned thoroughly and there are contaminants on its surface. Or, if the bearings are touched by sweaty hands after cleaning, they are not packaged or installed promptly and are exposed to air for a long time, which can lead to moisture intrusion and contamination from the air;
5) Environmental temperature and humidity, as well as exposure to various environmental media;The rust preventative has lost its effectiveness or fails to meet the required quality standards.
Union Trade Tech. Co., Ltd. is extracted from Baidu Encyclopedia,