71909 CD/P4ATBTC
71900 Series Super Precision Angular Contact Ball Bearings
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Part No.
Part No.
71909 CD/P4ATBTC
Basic Information
System of measurement
Metric
Weight
0.39 kg
Tolerance class
P4A
Seal type
Open
For load direction
Angular Contact
Main Dimensions
Bore diameter
45 mm
Bore diameter tolerance
-0.004mm to 0
Outside diameter
68 mm
Outside diameter tolerance
-0.004mm to 0
Width
36 mm
Width tolerance
-0.2mm to 0
Contact angle
15 °
Ball & Washer Dimensions
Ball diameter
6.35 mm
Ball quantity
23
Performance
Temperature range
- 30°C to 110 °C
Radial dynamic load rating
6322 lbf
Radial static load rating
6412 lbf
Limiting speed
41 X 1000 rpm
Lubrication
Lubricated
Matched arrangement
Triplex Back-to-Back (TBT)
Number of bearings in matched set
3
Universal matching bearing
No (Standard)
Preload
Moderate / Class C
Materials
Ring material
Chrome Steel
Ball material
Chrome Steel
Cage material
Phenolic
Technical Drawings
No drawings available at the moment, will be launched soon
In Stock
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71909 CD/P4ATBTC Bearing Product Overview & Core Advantages
The 71909 CD/P4ATBTC is a metric precision angular contact ball bearing supplied in a triplex back-to-back (TBT) matched set. This configuration is engineered to deliver exceptional system rigidity and stability, making it ideal for applications requiring high precision and the ability to withstand combined loads (radial and axial). The bearings are preloaded to Moderate / Class C and manufactured to a P4A tolerance class, ensuring superior running accuracy and consistent performance in demanding operational conditions.
71909 CD/P4ATBTC Bearing Model Code Explained, Specifications & Naming Convention
The model number 71909 CD/P4ATBTC is decoded as follows:
- 71909: Basic bearing series, indicating a 45 mm bore, 68 mm OD, and 12 mm width per single bearing.
- C: Denotes a 15° contact angle, optimized for high-speed operation and moderate axial load capacity.
- D: Indicates the bearing is part of a matched set with specific preload and tolerance pairing.
- P4A: Specifies the tolerance class, signifying very high precision for inner ring, outer ring, and running accuracy.
- TBT: Defines the Triplex Back-to-Back arrangement of the three bearings in the set, which maximizes moment stiffness.
- C: Specifies the Moderate preload level applied to the matched set.
71909 CD/P4ATBTC Bearing Structural Features & Performance Benefits
- Superior Rigidity and Stability: The triplex back-to-back (TBT) arrangement creates a highly rigid bearing system that effectively resists moment loads and shaft deflection, which is critical for maintaining precision in machine tool spindles and other high-performance equipment.
- High-Speed Capability: The 15° contact angle and phenolic resin cage are optimized for high-speed operation, contributing to a limiting speed of 41,000 rpm. The cage offers low weight and excellent sliding properties, reducing friction and heat generation.
- Precision Performance: Manufactured to P4A tolerance class, these bearings ensure minimal runout and vibration, leading to smoother operation, enhanced positioning accuracy, and longer service life for the entire assembly.
- High Load Capacity: The angular contact design efficiently supports combined radial and axial loads. The matched set distributes loads evenly across the three bearings, resulting in a high dynamic load rating of 6322 lbf and static load rating of 6412 lbf.
- Material Integrity: Constructed from chrome steel for both rings and balls, the bearing provides high hardness, wear resistance, and durability under demanding conditions.
71909 CD/P4ATBTC Bearing Typical Application Areas
This precision bearing set is specifically designed for high-performance applications where maximum rigidity and speed are paramount. Key industries and machinery include:
- Machine Tool Spindles: High-speed milling, grinding, and turning centers.
- Precision Spindles: PCB drilling and routing machines.
- High-Frequency Motors: Spindles for electric motors operating at very high RPM.
- Robotics: High-precision joints and arm actuators requiring minimal deflection.
