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80% Of Bearings Are Damaged Early, Which May Be Caused By Incorrect Installation Of Bearings

80% Of Bearings Are Damaged Early, Which May Be Caused By Incorrect Installation Of Bearings

2021-01-18

How to install it correctly?We share a valuable bearing installation article for you. As long as you spend a few minutes, you will have a certain understanding of the bearing installation, and extend the service life of the bearing.

Bearings are used to support the parts, but also used to support the rotation of the shaft parts, bearing types according to the friction properties of the points: sliding bearings and rolling bearings;According to the direction of the load: radial bearings, push bearings, radial thrust bearings, etc.


1. Assembly of sliding bearings

Sliding bearing is a kind of sliding tribological bearing, which is characterized by smooth work, low reliable noise, and can bear heavy load and large impact load. It can be divided into integral type, split type and tile type according to different structure forms.

(1) assembly of integral sliding bearings

Integral sliding bearing commonly known as the shaft sleeve, a kind of form is also the most simple of the sliding bearing, mainly adopt the method of pressure into and hammer to assembly, special occasions with hot pack, most of the collar is made of copper or iron, should be careful when assembling, use wooden hammer or hammer cushion block and the method of assembly and interference with press pressure into the larger size tolerance.Tilting must be prevented either by tapping or pressing, and the oil groove and oil hole should be in the desired position after assembly.

The inner hole of the bearing deformed after assembly should be trimmed. Reamer can be used for smaller size, and scraping can be used for larger size.At the same time, pay attention to control the fit clearance with the shaft within the tolerance range. In order to prevent the shaft sleeve from rotating when working, the contact surface of the shaft sleeve and the box body is equipped with a positioning pin or sewing screw.Because the hardness of the box and the sleeve material is not the same when drilling, it is easy to make the bit biased to the side of the soft material, the solution: one is before drilling with the sample punching on the hard material while punching, the other is with a short drill, in order to increase the rigidity of the drilling bit.

(2) assembly of split bearing

Split bearing, also known as split bearing, has the characteristics of simple structure, convenient adjustment and disassembly. Two bearing bushes are inlaid on the bearing bush, and a reasonable gap is adjusted by gasket at the joint.

The assembly of bearing bush and bearing body

The contact between the upper and lower bushing and the bearing body hole must be good. If it does not meet the requirements, the bearing body hole of the thick-walled bearing bush is taken as the benchmark, and the back of the bearing bush is scraped. At the same time, the steps at both ends of the bearing bush should be close to both ends of the bearing body.As long as the thin-walled tile is about 0.1mm higher than the middle part of the bearing body, it is not necessary to scratch.

② the bearing bush is installed in the bearing body, no matter radial or axial displacement is allowed, usually with the steps at both ends of the bearing bush to stop positioning or positioning pin positioning.

The bearing bush with scraping

To open four commonly used matching shaft research point, is generally lower bearing, and then scrape on bearing, in order to improve the efficiency when scraping the lower bearing don't mount bearing bushing and the cover, the basic requirements of the bearing contact, then the bearing shell and cover pressure, scraping the research on the bearing shell, further revised lower bearing contact points.The tightness of the shaft with scraping can be adjusted with the increase of scraping times by changing the thickness of the gasket.When the bearing cover is tightened, the shaft can rotate easily without obvious clearance, and the contact point meets the requirements, that is, the scraping is completed.

④ measurement of bearing clearance

The size of bearing clearance can be adjusted by the gasket at the middle parting surface, or obtained by directly repairing and scraping the bearing bush.Measurement usually USES the pressure bearing clearance lead method, take some lead wire diameter greater than the bearing clearance, in the journal and points on the surface, then tighten the nut to split pressure, then fix the nut, remove the bearing cover, carefully remove the squished lead wire, one from each section of the micrometer to measure thickness, according to the average thickness of the lead wire can know the bearing clearance.The clearance of the general bearing should be 1.5‰-2.5‰ (mm) of the shaft diameter, and the smaller clearance value should be taken when the diameter is larger.If the shaft diameter is 60mm, the bearing clearance should be between 0.09-0.15mm.

2. Assembly of rolling bearings

Rolling bearings have the advantages of small friction, small axial size, convenient replacement and simple maintenance.

(1) Technical requirements for assembly

(1) The end face of the rolling bearing marked with code should be installed in the visible direction so as to check when replacing.

② The arc radius of the shaft journal or the step of the shell hole should be less than the corresponding arc radius on the bearing.

(3) After the bearing is assembled on the shaft and the shell hole, there should be no skew phenomenon.

(4) in the two coaxial bearings, there must be one shaft movement with the thermal expansion of the shaft.

⑤ When assembling rolling bearings, dirt must be strictly prevented from entering the bearings.

⑥ The bearing after assembly must be flexible, low noise, and the working temperature should not exceed 65℃.

(2) Assembly method

When assembling bearings, the most basic requirement is to make the added axial force act directly on the end face of the ring of the bearing (when mounted on the shaft, the added axial force should act directly on the inner ring, and when mounted on the hole, the added force should act directly on the outer ring).Try not to affect the scroll.The assembly methods include hammer method, press assembly method, hot assembly method, freezing assembly method and so on.

1) hammer method

Use a hammer to pad the copper rod and some relatively soft materials and then hammer the method, pay attention to do not make the copper end and other foreign bodies fall into the bearing raceway, do not directly hammer or punch the inner and outer ring of the bearing directly, so as not to affect the accuracy of the bearing or cause bearing damage.

② screw press or hydraulic press assembly method

For bearings with large interference tolerances, screw presses or hydraulic presses can be used for assembly.Before pressing, the shaft and bearing should be laid flat and coated with a little lubricating oil. The pressing speed should not be too fast. After the bearing is in place, the pressure should be removed quickly to prevent damage to the bearing or shaft.

(3) hot pack

The hot loading method is to put the bearing in the oil and heat it to 80℃-100℃, so that the inner hole of the bearing is enlarged and fitted to the shaft, which can prevent the shaft and bearing from damage.For the bearing with dust cover and sealing ring, the internal has been filled with grease is not applicable to the hot loading method.

(3) Tapered roller bearing clearance is adjusted after assembly, the main methods are gasket adjustment, screw adjustment, nut adjustment, etc.

(4) When assembling thrust ball bearings, the tight ring and loose ring should be distinguished first. The inner diameter of the tight ring is slightly smaller. The assembled tight ring and shaft remain relatively static when working, and it always depends on the step or hole end face of the shaft.

3. Instructions for rolling bearings

When installing the bearing, the force should be uniform and it can not be hammered directly.For example: with large interference, the bearing should be heated in an air heating furnace or an oil furnace with automatic temperature control, and the heating temperature should be strictly controlled below 120°.

Bearings equipped with nylon retainer are capable of long-term continuous and stable operation at -40°-120°, and should not operate for more than 4 hours at 150°, with a short peak temperature of 180°.

The warehouse for bearing storage should be clean, dry and not allowed to be stored in the same warehouse with chemical products, the relative humidity should not exceed 65%, and the bearing is not allowed to be stored on the ground.

(1) installation and use of deep groove ball bearings

When installing the bearing, the force should be uniform and it can not be hammered directly.For example: with large interference, the bearing should be heated in an air heating furnace or an oil furnace with automatic temperature control, and the heating temperature should be strictly controlled below 120°.

Bearings equipped with nylon cages can operate continuously and stably at -40°-120° for a long time, and should not work for more than 4 hours at 150°, and the transient peak temperature should not exceed 180°.

The warehouse for bearing storage should be clean, dry and not allowed to be stored in the same warehouse with chemical products, the relative humidity should not exceed 65%, and the bearing is not allowed to be stored on the ground.

Stock bearings should be cleaned again every other year for rust proof packaging.

(2) installation and use of angular contact ball bearings

When installing the bearing, the force should be uniform and it can not be hammered directly.For example: with large interference, the bearing should be heated in an air heating furnace or an oil furnace with automatic temperature control, and the heating temperature should be strictly controlled below 100°.

Bearings equipped with nylon retainer can work continuously and stably at -40°-120° for a long time, and should not work for more than 4 hours at 150°, with a short peak temperature up to 180°.

The warehouse for bearing storage should be clean, dry and not allowed to be stored in the same warehouse with chemical products, the relative humidity should not exceed 65%, and the bearing is not allowed to be stored on the ground.

(3) Self-aligning roller bearings are installed and used

The user should choose the appropriate fit and bearing force clearance according to the operation requirements.Please check the bearing code first after unpacking.

Before the installation of the bearing, if it is necessary to add grease in the bearing, the grease must be cleaned and appropriate.

When installing, it is advisable not to directly hammer the inner ring, outer ring end face and roller, so as not to crack the inner ring or the middle and small guard edge.Usually the user should put the bearing into the mineral oil heating to 90°-100° immediately installed on the spindle.Avoid using local spray burning method for bearings. When it is difficult to "heat charge", users should also use special sleeve for installation.

The bearing should have good sealing and dustproof device and lubrication in use, and can not break oil.

The bearing warehouse should be clean and dry, without environmental pollution, the bearing stacking does not fall, and the packaging is not damaged.Bearings that are in stock for more than 1 year must be cleaned and oiled again.

(4) Thrust self-aligning roller bearings are installed and used

When installing bearings, the bearing oil seal should be cleaned and then coated with clean high-quality lubricating oil.

When installing the bearing, the force should be uniform and it can not be hammered.If the fit interference is large, the bearing should be placed in mineral oil and heated to 90°-100° before installation immediately.

The warehouse for bearing storage should be clean and clean, and the relative humidity should not exceed 65%.

The stock bearings should be cleaned and oiled once every other year, and the oil seal packaging should be kept in good condition.

When using bearings, there should be a good sealing and dustproof device, and the working condition should be checked regularly.

(5) installation and use of cylindrical roller bearings

The bearing is separated type, the user can adjust the clearance according to the need when installing.

Before use, the bearing should be cleaned with gasoline or kerosene and kept well lubricated.

When installing the bearing, the bearing should be pressed into the parts, and it is strictly prohibited to knock.

The bearing storage place should be clean and ventilated to avoid moisture. Bearings that need to be kept for a long time should be regularly rust proof.

(6) Thrust ball bearing installation and use

When installing the bearing, the bearing seal should be removed, washed and then coated with clean quality lubricating oil.

When installing the bearing, the force should be uniform and it can not be hammered.If the fit interference is large, the bearing should be placed in mineral oil and heated to 90°-100° before installation immediately.

The warehouse for bearing storage should be clean and clean, and the relative humidity should not exceed 65%.

The stock bearings should be cleaned and oiled once every other year, and the oil seal packaging should be kept in good condition.

When using bearings, there should be a good sealing and dustproof device, and the working condition should be checked regularly.


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