Release time : 2015-06-10 13:03:38
Can You Identify Roller Bearings vs Ball Bearings Well?
By Bearing Manufacturer>Bearing News>Can You Identify Roller Bearings vs Ball Bearings Well?
Roller bearings vs ball bearings both have their advantage and disadvantage. Different characteristic meet with different requirements. Therefore you should clearly understanding your requirements, and then have a good knowledge of which kind of bearing is the most suitable one, at last you could make a decision.
Roller bearing: is a bearing which carries a load by placing round elements between the two pieces. The relative motion of the pieces cause the round elements to roll with very little rolling resistance and with little sliding. The classical one is Needle Roller Bearings.
Roller bearings vs ball bearings, taking roller as rolling-element bearing which have the advantage of a good tradeoff between cost, size, weight, carrying capacity, durability, accuracy, friction, and so on. Other bearing designs are often better on one specific attribute, but worse in most other attributes, although fluid bearings can sometimes simultaneously outperform on carrying capacity, durability, accuracy, friction, rotation rate and sometimes cost. Only plain bearings are used as widely as rolling-element bearings.
Rolling-element bearings which use roller as rolling element often work well in non-ideal conditions, but sometimes minor problems cause bearings to fail quickly and mysteriously. For example, with a stationary (non-rotating) load, small vibrations can gradually press out the lubricant between the races and rollers. Without lubricant the bearing fails, even though it is not rotating and thus is apparently not being used. For these sorts of reasons, much of bearing design is about failure analysis. Vibration based analysis can be used for fault identification of bearings.
A ball bearing: is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The most typical one is Deep Groove Ball Bearings.
The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this by using at least two races to contain the balls and transmit the loads through the balls. In most applications, one race is stationary and the other is attached to the rotating assembly (e.g., a hub or shaft). As one of the bearing races rotates it causes the balls to rotate as well. Because the balls are rolling they have a much lower coefficient of friction than if two flat surfaces were sliding against each other.
Roller bearings vs ball bearings, ball bearings tend to have lower load capacity for their size than other kinds of rolling-element bearings due to the smaller contact area between the balls and races. However, they can tolerate some misalignment of the inner and outer races.
If a bearing is not rotating, maximum load is determined by force that causes non-elastic deformation of balls. If the balls of Ball Miniature Bearings are flattened, the bearing does not rotate. Maximum load for not or very slowly rotating bearings is called "static" maximum load.
If that same bearing is rotating, that deformation tends to knead the ball into roughly a ball shape, so the bearing can still rotate, but if this continues for a long time, the ball fails due to metal fatigue. Maximum load for rotating bearing is called "dynamic" maximum load, and is roughly two or three times as high as static max load.
Although roller bearings had been developed since ancient times, the first recorded patent on ball bearings was awarded to Jules Suriray, a Parisian bicycle mechanic, on 3 August 1869. The bearings were then fitted to the winning bicycle ridden by James Moore in the world's first bicycle road race, Paris-Rouen, in November 1869.
Ball bearings were first produced in Europe so they were standardized to metric dimensions. American manufacturers came along later so they produced ball bearings in metric dimensions prior to the early-1990s.