With high running accuracy, high-speed performance, and high system rigidity, TKW super-precision bearings are ideal for machine tools and other precision applications, such as high-speed finishing stands for steel wire, racing cars engines and transmissions, and innovative fluid treatment applications. The bearings also minimize noise, vibration, and heat generation.
Our assortment includes different bearings’ steel grades, standard steel bearings,stainless steel, and hybrid bearings with ceramic rolling elements, particularly suited for high-speed applications.
TKW manufactures super-precision angular contact ball bearings for shaft diameters from 6 to 360 mm. Application requirements vary, and as a result, the TKW assortment of super-precision angular contact ball bearings includes four ISO dimension series, in numerous executions. The wide selection of designs and variants enables them to be incorporated into virtually every machine tool application as well as other applications where precision bearings are required.
TKW super prcision bearings Have many different type design:
Super-Precision Angular contact ball bearings Super Precision Cylindrical Roller Bearings Double Direction Angular Contact Thrust Ball Bearings Super Precision Axial-Radial Cylindrical Roller Bearings
Angular contact thrust ball bearings for screw drives Thin Section Bearings Cross Roller Bearings
Single row TKW super-precision angular contact ball bearings are inseparable. Like all angular contact ball bearings, there are raceways on the inner and outer rings, and the raceways displace relative to each other in the direction of the bearing axis. This means that in addition to radial loads, these bearings can also support axial loads in one direction. Radial loads create axial forces in these bearings that need to be balanced by reaction forces. Therefore, angular contact ball bearings are always adjusted to a second bearing or used in sets. The rings on one or both bearing rings can have different heights. Each bearing has as many balls as possible, which are guided by a window cage.
The TKW assortment of super-precision angular contact ball bearings includes bearings in the following dimension series:
· Ultra light 718 series
· Extremely light 719 series
· Light 70 series
· Robust 72 series
The cross sections of the four bearing series are compared for the same bore and same outside diameters. Each bearing series has characteristic features that make it particularly suitable for certain bearing applications.
Series 718 bearings should be selected when low cross-sectional height is a critical design parameter. If there is more radial space and the load is not very heavy, bearings from the 719 or 70 series can be used. Series 72 bearings have the largest cross-sectional height for a given bore diameter and are suitable for heavy loads at relatively low speeds.
If high stiffness is required, bearings of the 718 and 719 series are typically used. Bearings in both series contain the largest number of balls relative to the selected bore diameter and can also accommodate the largest shaft diameters relative to their outer diameter. These two properties are particularly important for system stiffness, since the stiffness of the spindle increases with its shaft diameter, and the stiffness of the bearing arrangement increases with the number of balls.
Super-precision angular contact ball bearings are manufactured with the following contact angles:
· A 15° contact angle, designation suffix C
· A 25° contact angle, designation suffix AC
For S70 W series bearings, the contact angle is 18° (designation suffix F). For other series, bearings with an 18° contact angle (designation suffix F), are available on request.
A larger contact angle provides a higher degree of axial stiffness and a higher axial load carrying capacity. However, speed capability, radial stiffness, and radial load carrying capacity are reduced.
High-capacity D design bearings
Type D bearings are designed to carry heavy loads at relatively high speeds at low to moderate operating temperatures. D design bearings contain the largest number and size of balls compared to other precision angular contact ball bearings. Their close contact provides relatively high stiffness and the highest possible load-carrying capacity.
Typical applications for bearings in the 718 .. D series include:
· Machine tools, e.g. multispindle drilling heads
· Robotics
· Printing
· Measuring systems
· Racing car wheels
Typical applications for bearings in the 719 .. D and 70 .. D series include:
· Machining centres (horizontal and vertical) · Semiconductor industry, e.g. units for detecting defects on silicon wafer chips
· Milling machines · Boat gyrostabilizers
· Lathes · Telescopes
· External and surface grinding machines · Microturbines
· Boring machines · Racing/super car wheels
· Machines for cutting or polishing stones and glass · Medical equipment
Typical applications for bearings in the 72 .. D series include:
· Machine tool spindles e.g. live centre spindles
· Lathes (main spindles, tailstock)
· Grinding machines
· Boring machines
· Parallel Kinematic Machines (PKM)
· Dynamometers for engine testing
· High-speed turbochargers
Typical applications for bearings in the 72 .. D series include:
· Machine tool spindles e.g. live centre spindles
· Lathes (main spindles, tailstock)
· Grinding machines
· Boring machines
· Parallel Kinematic Machines (PKM)
· Dynamometers for engine testing
· High-speed turbochargers
High-speed E design bearings
High Speed E design bearings have a more open close contact and a maximum number of smaller balls compared to D design bearings. Therefore, they can accommodate very high speeds but do not have the same high load carrying capacity as D design bearings. E design bearings have slightly higher speed capabilities and can handle heavier loads than B design bearings.
Typical applications for bearings in the 719 .. E and 70 .. E series include:
· High-speed machining centres (horizontal and vertical)
· High-speed milling machines
· High-speed internal grinding machines
· High-speed spindles for PCB drilling
· Woodworking machines
High-speed W design bearings
W design bearings have a more open close contact and a maximum number of smaller balls compared to D design bearings. Therefore, they can accommodate very high speeds but do not have the same high load carrying capacity as D design bearings.
W Design bearings are only available as hybrid (balls made of bearing grade silicon nitride), sealed and lubricated for life, angular contact ball bearings with a contact angle of 18°. Their new cage design provides very high stability at low and medium speeds, reducing noise and vibration levels. They are available as a universally matched single bearing or as a matched set of two bearings arranged back-to-back or in series.
Typical applications for bearings in the S70 .. W series include medium-high volume production machines such as:
· Woodworking machines
· Transfer machines
· Small machining centres
· Tool grinding machines
High-speed B design bearings
Type B bearings are designed for high speed operation and are best suited for lighter loads and lower operating temperatures. Compared to E and D design bearings, B design bearings are equipped with a maximum number of very small balls. Smaller, lighter balls reduce the centrifugal load acting on the outer ring raceway, thereby reducing stress on the rolling contact surfaces. Since smaller balls require less space, bearing rings have a larger cross-sectional height, making them less susceptible to deformation due to bearing seat irregularities on the shaft or within the housing.
Typical applications for bearings in the 719 .. B and 70 .. B series include:
· Electro-spindles
· Metal cutting machines
· Woodworking machines
· Milling machines
· Machining centres
Cage of Single row super-precision angular contact ball bearings
Depending on their series and size, single row super-precision angular contact ball bearings are fitted as standard with one of the following cages:
· A cotton fabric reinforced phenolic resin cage, window-type, outer ring centred, no designation suffix
· A glass fibre reinforced PEEK cage, window-type, outer ring centred, designation suffix TNHA
· A glass fibre reinforced PEEK cage for bearings in the S70 .. W series, window-type, no designation suffix
o Ball centred for low and medium speeds
o Outer ring centred for high speeds
· A carbon fibre reinforced PEEK cage, window-type, outer ring centred, no designation suffix
· A glass fibre reinforced PA46 cage, window-type, ball centred, designation suffix TP
· A glass fibre reinforced PEEK cage, window-type, designation suffix VG275
· A machined brass cage, window-type, outer ring centred, designation suffix MA
The lightweight polymer cages reduce inertial and centrifugal forces while maximizing the effectiveness of the lubricant. Other cage materials and designs are available on request.
Hybrid angular contact ball bearings (designation suffix HC) have rings made of bearing steel and rolling elements made of bearing grade silicon nitride (ceramic). As ceramic balls are lighter and have a higher modulus of elasticity and lower coefficient of thermal expansion than steel balls, hybrid bearings can provide the following advantages:
· Higher degree of rigidity
· Higher speed capability
· Reduced centrifugal and inertial forces within the bearing
· Minimized stress at the outer ring rolling contacts at high speeds
· Reduced frictional heat
· Less energy consumption
· Extended bearing and grease service life
· Less prone to skid smearing damage and cage damage when subject to frequent rapid starts and stops
· Less sensitive to temperature differences within the bearing
· More accurate preload/clearance control
Bearing arrangements using super-precision angular contact ball bearings can be specified as single bearings or as bearing sets.
Bearing sets
Sets of universally matchable bearings:
· Can be mounted in random order for any desired bearing arrangement. The bore and outside diameters of a set of universally matchable bearings are matched to within a maximum of one-third of the permitted diameter tolerance, resulting in better load sharing, when mounted, than single universally matchable bearings.
· Are available in different preload classes
· Like single, universally matchable bearings, are identified by the designation suffix G, but the position of the letter G in the designation is different
· Are not available in the S70 .. W series.
Super Precision Cylindrical roller bearings Super Precision
TKW super-precision cylindrical roller bearings are characterized by:
High speed capability
High radial load carrying capacity
High rigidity
Low friction
Low cross-sectional height
These bearings are therefore particularly well suited for machine tool spindles where the bearing arrangement must accommodate heavy radial loads and high speeds, while providing a high degree of stiffness.
TKW ultra-precision single-row cylindrical roller bearings have higher rotational speed capabilities than double-row bearings, which are more suitable for heavier loads.
TKW super-precision single row cylindrical roller bearings in the N 10 series are equipped as standard with a 1:12 tapered bore (type suffix K). Tapered holes are preferred because the taper allows for precise adjustment of clearance or preload during installation. The bearing has two integral flanges on the inner ring and no flange on the outer ring. To improve lubricant flow, these bearings can be equipped with lubrication holes in the outer ring upon request.
Basic design bearings
PA66 cage: without glass fiber reinforcement, bore diameter up to 80 mm (type suffix TN)
Made of fiberglass reinforced material, suitable for larger sizes (model suffix TN9), Special for most precision applications
High speed design bearings
Features optimized internal geometry and cage for higher speeds
-- Contains fewer rollers than basic design bearings
-- Equipped with an outer ring center cage designed to optimize lubricant effectiveness and avoid insufficient lubricant in motion at high speeds. The cage can be: Asymmetrical cage made of glass fiber reinforced PEEK (model suffix TNHA)
The symmetrical cage is made of carbon fiber reinforced PEEK (model suffix PHA), which provides better guidance and promotes better lubrication conditions for superior performance. Compared to bearings with glass fiber reinforced PEEK cages, bearings with carbon fiber reinforced PEEK cages can be 30% faster in grease lubricated applications and 15% faster when lubricated in oil and gas systems.
Hybrid cylindrical roller bearings (type suffix HC5) are available in the N 10 series and, on request, the NN 30 series. They have rings made of bearing steel and rollers made of bearing-grade silicon nitride (ceramic). Since ceramic rollers are lighter than steel rollers and have a higher elastic modulus and lower thermal expansion coefficient, hybrid bearings can offer the following advantages:
-- higher rigidity
-- higher speed capabilities
-- Reduce centrifugal and inertial forces in bearings
-- Minimized stress at outer ring rolling contact at high speeds
-- Reduce friction heat
-- consume less energy
-- Extend bearing and grease life
-- When starting and stopping frequently and quickly, it is less likely to cause slippage, smear damage and cage damage.
-- Not very sensitive to temperature differences within the bearing
-- More precise preload control
Double direction angular contact thrust ball bearings
TKW double-direction angular contact thrust ball bearings are designed for axial positioning of spindles in both directions. These bearings are designed to be mounted in the same housing bore in combination with cylindrical roller bearings of the NN 30 K or N 10 K series. This bearing combination simplifies machining of the housing bore.
The nominal bore and outside diameters of bidirectional angular contact thrust ball bearings are the same as the corresponding cylindrical roller bearings. However, the outer diameter tolerance of the housing washer, combined with the housing bore and geometric tolerances recommended for ultra-precision cylindrical roller bearings under light to normal loads and rotating inner ring loads (housing tolerances under standard conditions), will be produce appropriate results. Radial clearance in housing bore. If the outer ring of the thrust bearing is not clamped axially in the housing, this clearance is sufficient to prevent radial loads from acting on the thrust bearing.
Axial-radial cylindrical roller bearings
Ultra-precision axial-radial cylindrical roller bearings are commonly used to support rotary tables, indexing heads and multi-axis heads on machining centers. TKW produces ultra-precision axial-radial cylindrical roller bearings with shaft diameters from 80 to 850 mm. Their internal design, combined with a close-tolerance manufacturing process, allows these bearings to achieve radial runout better than P4 tolerance class and axial runout close to P4 tolerance class.
Thrust-radial cylindrical super-precision roller bearings can withstand radial load, bidirectional axial load and moment load, whether acting alone or simultaneously or in any combination. TKW super-precision axial radial cylindrical roller bearings offer high running accuracy, high load-bearing capacity and rigidity, making them ideal for turntables, indexing heads and multi-spindle heads. The bearing minimizes noise, vibration and heat.
-- Bear radial and axial loads in both directions
-- Designed for low to medium speed performance
-- Handling moment loads
-- tight tolerance
-- Minimize noise, vibration and heat
Angular contact thrust ball bearings for screw drives
Machine tools require screw drives to position workpieces or machine components quickly, efficiently, and accurately. To meet these requirements, the screw drive can be supported at both ends by TKW super-precision angular contact thrust ball bearings. The bearing has high axial stiffness, high axial load capacity, adapts to high speeds and rapid accelerations, and provides very high operating accuracy.
Angular contact thrust ball bearings for screw drives are ideally suited for screw drive applications, but are also suitable for other applications that require reliable radial and axial support and extremely precise axial guidance of the shaft.
Thin Section Bearings
TKW's precision thin section bearing line offers high accuracy and low profile design in standard stainless steel or chrome steel configurations. This line includes deep groove and angular contact configurations with special features available to meet specific application requirements.
Design Attributes:
· Precision tolerances – meet ABEC 5F (ISO P5) or ABEC 7F (ISO P4) for high running accuracy.
· Material selection – standard offerings include 440C stainless steel and 52100 chrome steel.
· Superfinished raceways – provide a smooth surface finish to reduce internal friction and vibration.
· High quality ball complement – grade 5 or better balls optimize smooth rolling performance.
· Retainers – various configurations and materials to meet performance needs.
Crossed Roller Bearings
Crossed Roller Bearings consist of an outer ring, an inner ring, and a plurality of rollers and spacers. The roller lies between the inner and outer ring with the spacers placed between the rollers to prevent the mutual friction between them thereby decreasing the torque resistance for rotation. There are six types of TKW Crossed Roller Bearings comprising of, the split outer ring type (CRBA), the split inner ring type (CRBB), the high rigidity type (CRBC), the split outer ring with mounting holes (CRBD), the high rigidity with mounting holes (CRBE) and the customized type (CRBX).
TKW designs and manufactures a variety of crossed roller bearings that can handle radial, thrust and moment loads at the same time. These compact bearings feature rollers crossed at right angles between inner and outer rings.
Widely used in machine tools, industrial robots and medical equipment because of their high rotational accuracy.
Roller guide options include a cage or separator as well as a full complement design. Both the cage and separator styles offer a small coefficient of friction for high-speed rotation. Full complement bearings handle heavy loads at low speeds.
Sealed and open designs are available. Sealed bearings incorporate synthetic rubber seals to protect against dust, dirt and grease.
