The general conditions for the stability of rotating friction coefficient values shown in general sliding bearing friction coefficient of 0.010.020.10.2 various types of bearings bearing friction coefficient. In order to facilitate comparison with sliding bearing, the friction torque of rolling bearings can be calculated by the formula of bearing bore:

M=uPd/2 (M: mN.m; U: friction torque, friction coefficient, table 1; P: N; D: the bearing load, the bearing of nominal diameter, mm). The effect of friction coefficient u bearing type, bearing load, speed, lubrication way more general conditions, stable friction coefficient reference rotation values as shown below.

For the sliding bearing, general u=0.01-0.02, sometimes as 0.1-0.2. Composite bearing friction coefficient: 0.03~0.18

Bearing friction coefficient u

Deep groove ball bearing 0.0010-0.0015

Angular contact ball bearings 0.0012-0.0020

Self-aligning ball bearing 0.0008-0.0012

Cylindrical roller bearings 0.0008-0.0012

Filled type needle roller bearings 0.0025-0.0035

With cage of needle roller bearings 0.0020-0.0030

Tapered roller bearing 0.0017-0.0025

Spherical roller bearings 0.0020-0.0025

0.0010-0.0015 thrust ball bearings

Spherical roller thrust bearings 0.0020-0.0025

4, the choice of rolling lubrication

Rolling bearing is a kind of important machine elements, performance of a mechanical equipment can fully play out depends on the bearing lubrication is appropriate, can say, lubrication is the necessary condition to ensure the normal operation of the bearing, it plays an important role in improving the carrying capacity and service life of bearing. Regardless of the type of lubricant, lubrication are to play the following roles in rolling bearing:

(1) reduce the friction between the metal, reduce the wear.

(2) increase the contact area of the oil film formation, reduce the contact stress.

(3) ensure that the rolling bearing in the high-frequency contact stress under normal operation, long time, extend the fatigue life,

(4) to eliminate the friction heat, reduce the surface temperature of the bearing work, prevent burns.

(5) is dustproof, anti rust, anti erosion.

Therefore, proper lubrication is important for normal operation of rolling bearings. Lubrication design of rolling bearings mainly includes: determining reasonable lubrication method, the correct selection of lubricant, determine the quantitative juice lubricant dosage calculation and changing period. Rolling bearing lubrication can generally be divided into according to the lubricants used lubricating oil, grease and solid lubricant three categories. The oil lubrication is wider than other lubrication temperature range, more suitable for bearing in high speed and high load conditions of work; at the same time, because the oil also has the equipment maintenance and convenient replacement, lubricant in friction such as gear can also advantages of lubrication, so far, bearing lubrication the most common. Grease with sealing device, low cost and simple repair grease, low cost, low speed, medium speed, the bearing temperature in the operation is used very common. Especially the advent of antiwear additives in recent years, improve the lubrication performance of grease, the grease is applied more widely. If the use of oil and grease lubrication is not up to the requirements of the bearing lubrication condition, or can not meet the specific working conditions, you can use the solid lubricant, or try to improve the lubrication performance of the bearing itself.

The running speed of the bearing is mainly affected by frictional heating inside the bearing temperature rise caused by the restrictions, when the speed exceeds a certain threshold, the bearing will burn and not continue to rotate.