Classification, maintenance and sealing of Thin Section Bearing
Table of Contents
Thin Section Bearing product features
In order to obtain low friction torque, high rigidity, and good rotation accuracy of the bearing, steel balls with small outer diameters are used. The use of hollow shafts ensures light weight and space for wiring. thin section bearings realize an extremely thin bearing section, and also realize miniaturization and weight reduction of products. The variety of products expands its range of uses.
thin section 6700 and 6800 series have various dust cover forms, flanged forms, stainless steel forms, wide forms, etc., and the varieties are complete.
Classification of thin section bearings
Generally divided into plastic seal-RS, iron seal-ZZ, plane, iron card-K, copper card-M. For example: 608RS, 6914ZZ, 61926K, 61844M.
Thin Wall Crossed Roller Bearings
CRA series thin section crossed roller bearings (outer ring split type) are small and lightweight crossed roller bearings made of thin outer ring and inner ring. The mounting parts of the bearing can be lightweight..
The inner and outer rings of CRB series thin section crossed roller bearings (outer ring split type) are miniaturized to the maximum extent. The structure is that the outer ring is divided into two parts, and the inner ring is an integral structure, which is most suitable for the inner ring. Where the rotation accuracy is high..
CRE series thin section crossed roller bearings (inner ring split type) have a structure that the inner ring is two divided parts and the outer ring is a one-piece structure, which is most suitable for places where high rotation accuracy of the outer ring is required.
thin section ring bearings are highly accurate, very quiet and have a high load-carrying capacity. These ball bearings are available in three designs and are extremely small and mostly square in cross-section. In these series, the cross section remains the same even for larger shaft diameters and bearing bores. These bearings are therefore called constant section. It is this feature that brings the standard ISO series.
thin section ring bearings are distinguished from conventional bearings. Therefore, it is possible to choose a larger cross section and use a bearing with a higher load capacity without having to change the shaft diameter. thin section ring bearings can be designed to be extremely light and require very little space.
Deep groove ball bearings, four-point contact bearings, angular contact ball bearings
thin section ring bearings can be deep groove ball bearings (C), four-point contact bearings (X), angular contact ball bearings (E). All of the above designs are available in different series. The series depends on the size of the cross section. The ball matches the series. Deep groove ball bearings can support axial and radial loads in both directions. Four-point contact bearings can support bidirectional.
Axial loads as well as radial loads; therefore they behave in the same way as double row angular contact ball bearings. Angular contact ball bearings can match the optimum number of balls and have a contact angle of 30°. They support higher radial loads than deep groove ball bearings or four-point contact bearings, and can support axial loads originating from the same direction. For special needs, Angular contact ball bearings are also available as matching bearings. Therefore, the rigidity and load-carrying capacity of these combinations are much higher than single-bearing products.
Thin Section Bearing Repair Procedures
1. Bearing installation and removal must be careful
Different types and sizes of thin section deep groove ball bearings have different installation methods and tools, including mechanical or hydraulic. Here is mainly to explain some common basic installation methods and precautions.
First, do not install hard on the ball, which will cause partial overloading of the ball and the contact surface, resulting in premature bearing failure.
Second, do not use hard tools, such as hammers, screwdrivers, etc. to hit the surface of the bearing, which will break or brittle the outer ring of the bearing.
2. Cleaning of bearings
A clean operating environment is very important for bearings. The surface roughness accuracy of the rotating surface and rolling elements of the thin section deep groove ball bearing ring is about 1/10 μm. If the smooth ball surface is contaminated, the impact is very serious.
The lubricating layer between the rolling surfaces is usually 0.2~1 μm, and the particulate impurities larger than the lubricant particle size will be excessively rolled by the rolling elements and generate local pressure in the spherical roller bearing steel, which will eventually lead to permanent material fatigue.
In addition to this, dust particles in the external environment up to 10 μm in size can also cause damage to spherical roller bearings. Because of this, a clean and tidy working environment is so important for bearings.
3. Process inspection of bearings
In the process of use, the working temperature of the bearing is sensed by heat drying. If it is found that the temperature exceeds the specified limit, it will automatically alarm to prevent the occurrence of shaft burning.
A high temperature often indicates that the bearing is in an abnormal condition. High temperatures are also detrimental to bearing lubricants. Sometimes the overheating of thin section deep groove ball bearings can be attributed to the lubricant of the bearing. If the bearing is continuously rotated for a long time at a temperature exceeding 125°C, the bearing life will be reduced.
The reasons for the high temperature bearing include: it may be that the bearing lubrication is insufficient and the lubricant is unqualified, and it contains impurities. When the load is too large, it may also be that the clearance inside the bearing is not enough and the oil seal produces friction and so on.
Thin Section Bearing Seals
Corresponding sealing devices are installed on both ends of the bearing, but many people do not know what the sealing device does? Let’s take a look at what the sealing device does to thin section bearings.
1. Keep the grease (oil) inside the bearing from being lost during use, and ensure that the bearing is in a lubricated state;
2. Protect the dust or harmful gas from outside the bearing from entering the bearing cavity to prevent damage to the bearing.
The sealing structure of the sealing ring is various, so the sealing effect is also different. If there is a gap between the seal ring and the rotating shaft, it is called a non-contact seal. The smaller the gap, the better the sealing effect, but the smaller the allowable shaft speed; on the contrary, the opposite is true.
If there is no gap between the seal ring and the rotating shaft, it is called a contact seal. The larger the contact area of the seal ring’s contact lip, the better the sealing effect, but the smaller the allowable shaft speed, and vice versa. The main research content of sealing technology is to research and develop corresponding sealing devices applied in different working conditions, as well as the compatibility of the sealing ring material and the corresponding grease.
