High Precision Angular Contact Thrust Bearings for Spindle Double Direction

Angular contact thrust ball bearings are also one kind of thrust bearings,  This type of thrust bearing can be used to bear shaft and radial joint loads mainly bearing axial load, but it has higher precision, higher speed and lower noise than ordinary thrust bearings. So it mainly used in machine tools where need high precision and high speed.

Double direction thrust angular contact ball bearings are designed for bidirectional axial positioning of the spindle shaft. These bearings are combined with cylindrical roller bearings in the NN 30 K or N 10 K series and are mounted in the same housing bore. This bearing combination simplifies the machining of the housing bore.

The nominal inner and outer diameters of double direction thrust angular contact ball bearings are the same as the corresponding cylindrical roller bearings. However, the combination of the outer diameter tolerance of the raceway and the recommended housing bore diameter and shape and position tolerances (housing tolerances under standard conditions) for super-precision cylindrical roller bearings allows the housing bore to have an appropriate radial clearance. This clearance is sufficient to prevent thrust bearings from being subjected to radial loads if the outer ring is not axially compressed in the housing.

TKW offers double direction thrust angular contact ball bearings in two designs. Bearings in the BTM and BTW series have the same bore and outside diameter, but bearings height in the BTM series are 25% lower, making them particularly suitable for compact arrangements. They do not have the same high load carrying capacity and axial rigidity as bearings in the BTW series, but can operate at higher speeds.

BTW double direction thrust angular contact ball bearings

-- Consists of two single row thrust angular contact ball bearings with a contact angle of 60 degrees, designed back-to-back. This arrangement, combined with the multi-ball design, allows the bearing to accommodate high axial loads in both directions and provides high system rigidity.

-- Provides maximum load carrying capacity and system rigidity

-- Shaft diameters from 35 to 200 mm

--  Separate

-- When the shaft rings are compressed together, it has a preload within the preset range

-- Steel ball or ceramic ball can be provided.

-- According to the order requirements, the ring groove and three lubricating holes can be supplied on the seat ring (the model suffix is W33).

-- On request, a large bore design is available for mounting directly adjacent to the large diameter end of a cylindrical roller bearing with a tapered bore (e.g. BTW 60 CATN9/SP)

High-speed design bearings, BTM series

-- Consist of two non-separable single row angular contact ball bearings arranged back-to-back

-- Offer maximum speed capability

-- Are available for shaft diameters from 60 to 180 mm

--Are designed to accommodate axial loads in both directions

-- Have a resulting preload within a predetermined range when the inner rings are pressed together

--Available either with steel balls or ceramic balls (Hybrid bearings)

-- Are available with two different contact angles:

-- A 30° contact angle, designation suffix A

-- A 40° contact angle, designation suffix B

Bearings with a 30° contact angle can accommodate higher speeds while bearings with a 40° contact angle are more suitable for applications that require a higher degree of axial rigidity.

According to the ISO standard, BTM series bearings are radial bearings because they have a 30° or 40° contact angle. However, since these bearings are only intended to accommodate axial loads

Bearings in the BTW series are fitted as standard with the following cages:

· D ≤ 130 mm: two glass fibre reinforced PA66 cages, snap-type, ball centred, designation suffix TN9

· D ≥ 140 mm: two machined brass cages, snap-type, ball centred, designation suffix M

Bearings in the BTM series are fitted as standard with the following cages:

· D ≤ 130 mm: two glass fibre reinforced PA66 cages, window-type, ball centred, designation suffix TN9

· D ≥ 140 mm: two machined brass cages, window-type, ball centred, designation suffix M

The cages enable the preloaded bearings to run reliably at high speeds and to withstand rapid starts and stops as well as alternating loads. They also provide good grease retention.

Hybrid Ceramic Bearings

Hybrid ceramic angular contact thrust ball bearings (designation suffix HC) have chrome steel rings and rolling elements made of bearing grade silicon nitride (ceramic). Due to the lower weight, higher modulus of elasticity and lower coefficient of thermal expansion of ceramic bearing balls compared to steel balls, hybrid ceramic bearings offer the following advantages:

-- Higher stiffness

-- Improved RPM performance

-- Less centrifugal force and inertial force inside the bearing

-- Minimizes the stress on the rolling contact surface of the outer ring at high speed

-- Less frictional heat

-- Low power consumption

-- Longer bearing and grease life

-- When subjected to frequent rapid start and stop, it is not easy to slip and scratch and damage the cage

-- Less sensitive to differences in temperature within the bearing

-- Higher preload/clearance control accuracy