Characteristics and Parameters of 608ZZ Bearing

Size parameters of 608ZZ Bearing

608 bearing is a commonly used small rolling bearing, which is widely used in various occasions due to its small volume, light weight, easy installation, reliable quality, and low price. Its outer diameter is 8 millimeters, inner diameter is 22 millimeters, and width is 7 millimeters. Its structure is very compact and can be installed in very small spaces.

1. External Parameters of 608 Bearing

1.1 Shape Parameters

The external parameters of the 608 bearing consist of outer diameter, inner diameter, and width, as follows: outer diameter d=8mm, inner diameter D=22mm, and width B=7mm. In addition, it also has some additional parameters, such as the outer diameter, inner diameter, and thickness of the C-ring, which are d1=15mm, d2=24mm, and t=2mm, respectively.

1.2 Other Parameters

In addition to the above external parameters, the 608 bearing also has some other parameters, such as tolerance, surface treatment, fitting method, etc. Specifically, the allowable tolerance error is IT5-IT7, and surface treatment includes smooth surface, ball surface, grinding surface, and coating surface; The fitting methods include fixed inner ring position, hexagonal inner ring fixed type, and centripetal inner ring elastic fixed type.

2. Performance Parameters of 608 Bearing

2.1 Load Capacity

The load capacity of the 608 bearing is relatively low, with a basic rated dynamic load of 3.45kN, a basic rated static load of 1.37 kN, and a fatigue load limit of 0.057 kN.

2.2 Rotary speed

The maximum limit speed of the 608 bearing is 38000 r/min. Therefore, when using 608 bearings, appropriate rotational speed should be maintained to ensure normal operation.

2.3 Temperature

Due to the material of 608 bearings having a certain degree of heat resistance, their operating temperature should generally not exceed 120 ℃. At the same time, attention should also be paid to avoiding rapid temperature changes to prevent bearing wear.

3. Key Points for Selecting 608 Bearings

3.1 Application

608 bearings are commonly used in low-speed, low load applications such as power tools, electric vehicles, electric scooters, wind turbines, fans, machine tools, and water pumps. In addition, it can also be used in household appliances.

3.2 Material

The material of 608 bearings is generally GCr15 or GCr15SiMn steel. GCr15 steel has excellent wear resistance and impact resistance, and its heat resistance is also better than ordinary steel; The wear resistance and impact resistance of GCr15SiMn steel are superior to GCr15 steel, but the heat resistance is slightly inferior. Therefore, suitable materials should be selected according to the usage situation.

3.3 Lubricants

Lubricant selection

Lubricants are generally divided into oil lubricants and grease lubricants

Lubrication is an important issue for its performance. The suitability of lubricants or lubrication methods will greatly affect the lifespan of bearings

The function of lubrication is as follows:

1）Lubricate various parts of the bearing to reduce the rotational friction between the groove surface and the steel ball, the sliding friction between the steel ball and the retainer, and the sliding friction between the retainer and the groove guide surface.

2）Take away the heat generated by internal friction of the bearing and other heat transmitted from the outside, to prevent bearing heating and lubricant degradation.

3）Regularly form an appropriate oil film on the rolling contact surface of the bearing, alleviate the concentrated stress of impact load, and extend the fatigue life of the bearing.

4）Prevent corrosion of steel balls, channels, and retainers, as well as the intrusion of garbage, foreign objects, and moisture, and prevent rust and dust prevention of bearings.

According to temperature and working conditions, grease can be classified based on their allowable working temperature. The viscosity and lubrication ability of grease are affected by the working temperature. Bearings operated at a certain temperature must choose grease with the correct viscosity and good lubrication effect at the same temperature. Grease are manufactured in different operating temperature ranges and can be classified into low-temperature (lt), medium temperature (mt), and high-temperature (ht) grease. There is also a type of grease called EP (compression resistant) or EM (compression resistant with added molybdenum disulfide), which contains additives to enhance the strength of the lubricating oil film.

4. Summary

608 bearing is a commonly used small rolling bearing with an outer diameter of 8mm, an inner diameter of 22mm, a width of 7mm, a basic rated dynamic load of 3.45kN, a basic rated static load of 1.37 kN, a fatigue load limit of 0.057 kN, and a maximum limit speed of 38000 r/min. In addition, it has certain heat resistance and wear resistance, so it is widely used in low-speed and low load situations. However, when using 608 bearings, it is important to maintain appropriate speed and temperature to ensure normal operation.