Roller bearings

The owners of roller skates (as well as skateboards and scooters) know that the bearing is an important part of their sports equipment. It is transferred to it the load resulting from the movement. In order to reduce the cost of the product, many manufacturers put on the rollers inexpensive bearings that quickly fail. There is a need to replace the bearing, and here it is easy for an inexperienced person to make a mistake.

Very often, sellers due to their ignorance or a banal desire to earn extra money offer high-precision bearings (ABEC9 or 2nd class according to GOST). The accuracy class characterizes the maximum deviations of the basic parameters of the bearing, which, in turn, affects the rotational speed, the degree of friction of the rolling elements and, ultimately, the service life. However, is it necessary to install an ultra-precise and more expensive bearing for rollers, or will his “siblings” of the usual accuracy class cope with the load?

Consider the question on the example of the most common bearing for roller skates - 608ZZ normal accuracy class. Simplest 608 ZZmaintains loading to 325 kg in the movement (dynamic) and to 137 kg at rest (static). Its maximum speed is 32,000 rpm. For comparison: an electric motor without a multiplier produces 2800 rpm, and the crankshaft of a car rotates at a speed of 5000-6000 rpm.

Take a roller skate wheel diameter of 55 mm (rollers for aggressive and off-road skating).

Then in one revolution the wheel will cover a distance equal to π*d=3,14*0,055=0,17w/v 
Calculate the speed at which the limit is reached the frequency of rotation of the bearing: 32000 rpm*0.17 m/rev=5440 m/min=326.4 km/h.

It is clear that such a speed can not develop any amateur roller skating. When driving in the city, the scooter accelerates to 25-35 km/h, while professionals go down 150 km/h when going downhill (downhill).

It remains only to add that the bearing 608 with 2m accuracy class limit speed is 75000 rpm. To achieve it, you need to accelerate to speeds in excess of 750 km/h.

Installation of bearings of high accuracy class is advisable in especially critical assemblies. They are used in aircraft construction, precision machines and racing bollida. The load created during the operation of roller skates is also easily maintained by conventional bearings. Long service life will provide high-quality bearings firms SNR (France) и SKF (Sweden).

The site of the company VPK Podshipnik presents a wide selection of bearings. Convenient catalog and search will help you quickly find the right product.