# Angular Contact Ball Bearing

Single row angular contact ball bearings can not only withstand radial load and axial load in one direction, but also accommodate only axial load in single direction, radial loads produce axial forces in these bearings that need to be balanced by counter forces.Therefore, the single row angular contact ball bearings often need to be installed with other bearings which withstand axial load in the opposite direction. In other words, the angular contact ball bearings are commonly used in pair, or in groups with three, four and even five bearings. Angular contact ball bearings have higher limiting speed.

The bearings codes designation:

The bearings matched ways as below :

 DBThe load lines in a pair of bearings by back to back assembly are enlarging from the bearing axis. It can bear axial load in two directions and relative larger moment because of larger angular rigidity. DFThe load lines in a pair of bearings by face to face assembly are convergence toward the bearing axis. It can bear axial load in two directions and smaller moment because of smaller angular rigidity. DTA pair of bearings by series a ssembly only bear axial load in one direction, but it is able to bear larger axial load related to DB and DF. TBTThe tri-bearing matching TBT or TFT isobtained by increasing the same type of the bearing based on DB or DF There are higher axial and radial rigidity for TBT and TFT, so larger load can be supported. QBCThe four bearing matching QBC (or QFC) is obtained by matching double set of DB (or DF) bearings. QBT (or QFT) is formed when three bearings are installed in a same direction and another one back (or face) to them. PBCDivide the five bearings into two groups of three and two bearings respectively, in which the bearings are all installed in the same direction, PBC is formed when the groups match each other by back to back and PFC by face to face. If four bearings are installed in the same direction and another one back (or face) to them, then PBT (or PFT) is formed.

1.MONTON Angular contact ball bearings performance and Characteristics.

The MONTON precision angular contact ball bearings for spindle, have four size series, 718,719,70 and 72. With the same inner diameter, but the outer diameter and the width of 718,719,70 and 72 series increase in turn.

Fig.1  Angular contact ball bearing dimension series

MONTON precision angular contact ball bearings with 15° (C) and 25° (AC) contact angles. As for the angular contact ball bearings, the bigger the contact angle is, the greater the axial load capacity is, but the lower the limiting speed of bearings becomes. Therefore, the spindle, with high speed and small axial loadshould adopt the 15° angular contact ball bearings, whereas the 25° angular contact ball bearings should be adopted.

MONTON precision angular contact ball bearings with high-speed angular contact bearings (standard series), super high-speed angular contact ball bearings, high-speed sealed angular contact ball bearings and high-speed spindle bearings.

The inner ring, outer ring and rolling element of rolling bearing under normal operating conditions are made of high carbon chromium bearing steel, but the steel bearings cannot meet the requirements of such special conditions as high speed, wear-resisting, low temperature rising, long life and high reliability etc., then Si3N4 ceramics are believed to be present optimum rolling bearing materials to replace bearing steel.

Table 1. Main performance comparison between Si3N4 and bearing steel

 Performance Code and unit Si3N4 Bearing steel Density γ[g/mm3] 3.2 7.8 Coefficient of thermal expansion α[1/℃] 20～1000℃ 3.2×10-6 - 20～300℃ - 11.8×10-6 Modulus of elasticity E[N/mm2] 3.15×105 2.08×105 Poisson's ratio μ 0.26 0.3 Rigidity HV10 1700 700 Stress  intensity σB[N/mm2] 20℃ 700 2400 1000℃ 700 0 Fracture toughness Kie[MN/m1.5] 7 25 Coefficient of heat conductivity λ[W/m℃] 30～40 40～50 Electrical resistivity [Ωmm2/m] 1017～1018 0.1～1

MONTON also offers widely used hybrid angular contact ball bearings for spindles in high-speed precision machine tools and other high-speed precision machines, that is, the inner and outer rings are made of high-quality bearing steel materials, while the rolling element is made of Si3Nceramics.

Compared to the angular contact ball bearings made of steel, hybrid angular contact ball bearings with the same structure and size have high speed, high stiffness, low friction heat, and long life etc.

MONTON precision hybrid bearings with ceramic ball (HQ1) can significantly improve the speed, rigidity, reliability, and productivity of machine tools, and greatly reduce the friction heat, then extend the service life of host machine etc.

Table 2. The type and performance of MONTON angular contact ball bearing

 MONTON angular contact ball bearing series Structures Dimension series Bore size range Performance High precision angular contact ball bearing 718 C718 AC719 C719 AC70 C70 AC72 C72 AC 718：10～360mm719：8～460mm70： 8～380mm72： 8～220mm High speedLarge loading capacitySuit for greaseor oil-mist lubrication High speed angular contact ball bearing(hybrid ball bearing) H719 CH719 ACH70 CH70 ACH719 C/HQ1H719 AC/HQH70 C/HQ1H70 AC/HQ1 H719：8～220mmH70：8～220mmH719/HQ1：8～220mmH70/HQ1：8～220mm Super speedHigh rigiditySuit for air-oil or oil injection lubrication Super speed angular contact ball bearing(incl.hybrid ball bearing) HS719 CHS719 ACHS70 CHS70 ACHS719 C/HQ1HS719 AC/HQHS70 C/HQ1HS70 AC/HQ1 HS719：8～220mmHS70：8～220mmHS719/HQ1:8～220mmHS70/HQ1:8～220mm Super speed(higher t

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