How to repair the gap between the shaft and the bearing

The axial clearance inside the bearing can be achieved by moving the axial position of the outer ring.

1 Adjust the gasket method:

Fill a set of soft material (mild steel sheet or elastic paper) gasket between the bearing end cover and the end face of the bearing housing; When adjusting, first install the bearing end cover without putting the gasket, tighten the screws on the bearing end cover evenly on one side, and rotate the shaft by hand on the other side until the bearing rolling element is in contact with the outer ring and there is no clearance inside the shaft; At this time, the clearance between the bearing end cover and the end face of the bearing seat is measured, plus the axial clearance required by the bearing in normal operation; This is the total thickness of the gasket that needs to be placed, then the prepared spacer is placed between the bearing end cap and the housing end face, and finally the screw is tightened.

2 Adjustment Bolt Method:

Press the pressure ring on the outer ring of the bearing, and pressurize it with the adjustment bolt; Before pressurizing the adjustment, the pitch of the adjustment bolt should be measured first, and then the adjustment bolt should be slowly tightened until there is no clearance inside the bearing, and then the corresponding rotation angle of the adjustment bolt should be calculated. For example, the pitch is, the clearance required for the normal operation of the bearing, then the rotation angle required to adjust the bolt is 3600; At this time, the adjusting bolt is reversed 360, and the axial clearance obtained by the bearing is fixed, and then it can be fixed with a stop gasket.

1.If you have the conditions, you can remove the shaft, weld a layer of metal with a welding rod in the worn part, and then use a lathe to process it to achieve the use size, which is the root cause.

2.If you are using 22212 journal 60 mm and reduce the journal to 55mm you can replace the 22311 bearing with the limit speed and dynamic and static to fully meet the use.

You can put a little effort into the shaft where the shaft is in contact with the bearing, and it should be possible to solve this problem!

The specific operation is that you use a tapered punch to evenly punch the surface of the shaft, which can be expanded from the metal, and there will be a bulge on the surface of the shaft to a certain depth, and you can install the bearing on it and it should not move!

If the bearing has to be a problem, the only way to replace the bearing, there should be no technology to carry out the bearing in the current maintenance.

Try to see if you can align the concentricity of the shaft and the bearing, that is, the distance between the bearing and the shaft is equal, so that the noise will be smaller, and in the long run, it will either be a bad bearing or a bad shaft.

The best thing to do is to replace the bearings, because this is a problem that arises from long-term wear.

Add sleeves in the bearing position.

A layer of hard chrome is plated at the bearing position and regolden.

Hardfacing at the bearing position and remetallic processing.

Burr with a tapered punch at the bearing position (this method is not durable).

Adjust as much as possible within the adjustable range, and add a gasket if you can't adjust it.

The method of clearance adjustment is determined by the type of bearing, which can generally be divided into non-adjustable bearings and adjustable bearings.

The clearance non-adjustable bearing refers to the deep groove ball bearing that we are familiar with after the bearing leaves the factory, the clearance of the bearing is determined.

Spherical bearings and cylindrical bearings all belong to this category.

Adjustable clearance bearings refer to the relative axial direction in which the bearing raceway can be moved.

position to obtain the required clearance, belonging to this category are tapered bearings and angular contact ball bearings.

and some thrust bearings.

For the clearance of non-adjustable bearings, the industry has corresponding standard values (CN, C3, C4, etc.), and specific clearance ranges can also be customized. When the size of the shaft and bearing seat is known, the corresponding inner and outer ring matching amount is determined, and the clearance after installation cannot be changed. Since the amount of mating is a range in the design stage, there is also a range in the final clearance, which is not applicable in applications where clearance accuracy is required.

The adjustable bearing solves this problem very well, and by changing the relative axial position of the raceway, we can obtain a definite clearance value. As shown in the figure below, when moving the position of the inner ring, we can roughly get two kinds of clearances: positive and negative.

Generally speaking, the clearance size of the bearing needs to be quantified and tested according to the specific use conditions and requirements. Different structures and types of bearings will also have large differences in the size of their clearances. In addition, it is also necessary to consider factors such as the accuracy grade, material, and design size of the bearing.

Clearance ranges for some common bearings:- Common clearances for radial ball bearings are to the millimeter. - Tapered roller bearings have a common clearance of down to millimetre.

The common clearance for thrust ball bearings is segment trapping to millimeters. - Since the sliding bearing is supported by the contact surface for nuclear leakage, a certain gap is usually set, and the general clearance is about millimeter. It should be noted that if the bearing clearance is too small, it may lead to problems such as poor lubrication and overheating, affecting the life and performance of the bearing; If the clearance is too large, it will affect the accuracy and stability of the bearing, and even cause noise or other abnormal conditions.

Therefore, in specific applications, it is necessary to determine the appropriate clearance range of the bearing according to the equipment requirements and in combination with the actual situation.

The axis of the shaft and housing bore must be concentric during installation, otherwise the bearing will be damaged prematurely due to stress concentrations. In order to eliminate this undesirable phenomenon, a radial gap can be left between the outer diameter of the housing ring and the housing bore.

The center line of the shaft and the bearing surface of the shell should be vertical, and the shaft should not be tilted and deflected, otherwise the bearing will be damaged prematurely due to uneven load distribution. In order to eliminate the tilt of the bearing axis, the bearing surface of the housing ring can be padded with elastic materials such as oil-resistant rubber, leather, etc., or thrust ball bearings with spherical seats can be used.

Precautions: 1. The surface of the bearing is coated with anti-rust oil, which must be carefully cleaned with clean gasoline or kerosene, and then coated with clean high-quality or high-speed and high-temperature lubricating grease before installation and use. Cleanliness has a very significant impact on rolling bearing life and noise and vibration.

2. Do not directly hammer the end face and non-stressed surface of the bearing during installation, and use briquettes, sleeves or other tools to make the bearing evenly stressed, and do not transmit power through the rolling elements for installation.

3. If the installation surface is coated with lubricating oil, it will make the installation smoother. If the interference is large, the bearing should be heated to 80 90 after the bearing should be put into the mineral oil and installed as soon as possible, and the oil temperature of the group should not exceed 100, so as to prevent the tempering effect from reducing the hardness and affecting the size recovery. <>

The position of the axial fixing parts of the bearing was adjusted, and the clearance was adjusted. For example, adjusting the thickness of the reducer end cover gasket is to adjust the clearance.

Angular contact and tapered roller bearings can be adjusted appropriately during installation.

Deep groove ball bearings can control radial clearance by adjusting the axial clearance with a preload spring.

Alternatively, the initial clearance of the bearing can be selected by the fit, and it is not advisable to select the fit by the initial clearance (too many restrictions).

Bearing clearance is also known as bearing clearance. The so-called bearing clearance refers to the amount of movement when the bearing is not installed in the shaft or bearing housing, the inner ring or the outer ring is fixed, and then the bearing clearance is not fixed when the side is moved radially or axially. According to the direction of movement, it can be divided into radial clearance and axial clearance.

The size of the clearance (called working clearance) during operation has an impact on the rolling fatigue life, temperature rise, noise, vibration and other properties of the bearing.

According to the use conditions of the bearing, it is of great significance to select the most appropriate clearance value. The following main factors must be fully considered when selecting the actual bearing clearance:

1) The tightness of the bearing in the fit with the shaft and housing bore will lead to a change in the clearance value of the bearing. Generally, the clearance value will be reduced after the bearing is installed;

2) During the operation of the bearing, due to the different heat dissipation conditions of the shaft and the shell, the temperature difference between the inner ring and the outer ring will occur, which will lead to the reduction of the clearance value;

3) Due to the difference in the expansion coefficient of the shaft and shell materials, the clearance value will shrink or increase.

In general, the most suitable working clearance value for radial bearings is the basic group clearance value specified in the bearing clearance standard. The basic group clearance values are suitable for general conditions and should be preferred. When the basic group clearance cannot be used for the radial bearing working under special conditions, the auxiliary group clearance value can be selected.

For example, the group clearance value of deep groove ball bearings is suitable for mechanical parts where the bearing and the shaft and the housing bore adopt an interference fit that is tighter than the normal fit, or the working temperature difference between the inner ring and the outer ring of the bearing is large. The first group of clearance values can also be used under the working conditions such as the inclination of the center of the shaft and the center line of the housing bore is large, and in order to increase its axial load capacity, increase the ultimate speed of the bearing, and reduce the frictional resistance of the bearing. For shafts that require precise rotation or limited axial travel, bearings with a second group clearance value (small clearance value) are generally used, and a certain amount of preload is given if necessary"Preloading"to improve the rigidity of the shaft.

Only angular contact and tapered roller bearings can be properly adjusted during installation, and the clearance is basically fixed when the other bearings are selected.

Interference fit will cause the reduction of the game, generally the amount of interference, tapered bore bearing and adapter sleeve adjustment, there are complex formulas, not listed.

Plain bearings can be matched with axle clearance. When a bearing is not mounted on a shaft or bearing housing, one side of the inner or outer ring is fixed, and then the side of the bearing clearance is moved radially or axially. According to the direction of movement, it can be divided into radial clearance and return axial clearance.

The maximum amount of activity along the radial direction is called the radial trouser clearance, and the maximum amount of activity along the axial direction is called the axial clearance. In general, the greater the radial clearance, the greater the axial clearance, and vice versa.