Roller Bearing

Design

Single Row Roller bearing

As single row cylindrical precision roller bearings, the rollers are in linear contact with the raceways. They have higher radial load capacity compared with the point-contact ball bearings and are suitable for high speeds.

Double Row Roller bearings

TPI roller bearing company’s double row cylindrical roller bearings are, because of their second row of rollers, suitable for very heavy radial loads and provide increased radial stiffness. With a tapered bore design, NN precision roller bearings can reach even much higher rigidity. There are three integral flanges on the inner ring and no flanges on the outer ring, which makes the bearing are separable under a static state.

Cage

Precision roller bearings have two types of cages are available and categorized by the material with characteristics as below,

T2 cage, an engineered plastic molded cage. Although it has a favourable combination of strength and elasticity, an ageing process mostly influenced by temperature, time and lubricant should be taken care.

Machined brass cage, are mostly machined from cast or wrought brass. Unlike T2 cages, they are unaffected by most common bearing lubricants, temperature at the sacrisface of flexibility and light weight.

Grease

TPI roller bearing company cooperates with the best grease manufacturers in the world which allows us to suggest and apply the best lubricating selection for our customers.

Life

Bearing life is usually expressed as the number of hours an individual bearing will operate before material fatigue develops on either the raceways or the rolling element. The usual life rating for industrial applications is called “L₁₀” life. The L₁₀ life is the number of hours which that 90% of bearings will survive； or, conversely, 10% of bearings will have failed in the L₁₀ number of service hours. One thing to be noticed that, roller bearing has different factor when it comes to bearing life calculation.

Preload/Rigidity

Cylindrical roller bearings with tapered bores are usually used to allow easier adjustment of internal clearance. When the radial internal clearance becomes negative, the cylindrical roller bearings are preloaded. Generally, cylindrical roller bearings for the front end (fixed end) of the spindle are preloaded during operating. Bearing for the rear end (free end) are adjusted to produce a slight clearance during operating. The amount of radial internal clearance after mounted is based on several factors such as rotating speed, load, bearing size, required rigidity, etc.

Designation

The designation indicates the form, size, precision, internal structure, etc. of the bearing, and it’s shown as below:

Bearing type	NN	Double row with ribbed inner ring
Bearing type	NNU	Double row with ribbed outer ring
Dimension symbol	30
Bore number	6 – 26	below number 03 00: 10mm 01: 12mm 02: 15mm 03: 17mm above number 04 bore number x5 mm
Cage symbol	T2	Engineering plastic molded cage
Cage symbol	Blank	Machined brass
Tapered bore symbol	K	Tapered inner ring bore, taper ratio 1/12
Tapered bore symbol	Blank	Cylindrical inner ring bore
Radial clearance	C0NA	Internal clearance smaller than Normal
	C1NA	Internal clearance smaller than Normal
	C2NA	Internal clearance smaller than Normal
	NA	Normal internal clearance
Accuracy	P5	JIS standard class 5
	P4	JIS standard class 4
	P2	JIS standard class 2