71908 CD/P4ADBCGMM
71900 Series Super Precision Angular Contact Ball Bearings
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Part No.
Part No.
71908 CD/P4ADBCGMM
Basic Information
System of measurement
Metric
Weight
0.22 kg
Tolerance class
P4A
Seal type
Open
For load direction
Angular Contact
Main Dimensions
Bore diameter
40 mm
Bore diameter tolerance
-0.004mm to 0
Outside diameter
62 mm
Outside diameter tolerance
-0.004mm to 0
Width
24 mm
Width tolerance
-0.2mm to 0
Contact angle
15 °
Ball & Washer Dimensions
Ball diameter
6.35 mm
Ball quantity
21
Performance
Temperature range
- 30°C to 110 °C
Radial dynamic load rating
4478 lbf
Radial static load rating
3825 lbf
Limiting speed
56 X 1000 rpm
Lubrication
Grease
Matched arrangement
Duplex Back-to-Back (DB)
Number of bearings in matched set
2
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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71908 CD/P4ADBCGMM Bearing Product Overview & Core Advantages
The 71908 CD/P4ADBCGMM is a precision duplex angular contact ball bearing designed for applications demanding exceptional rotational accuracy and rigidity. This matched set features a Back-to-Back (DB) arrangement and a P4A tolerance class, making it ideal for high-speed spindles and other precision machinery. Its core advantages include the ability to support combined loads (radial and axial) from both directions simultaneously, high operational stability due to the duplex preload, and excellent performance in demanding environments.
71908 CD/P4ADBCGMM Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 71908 | Basic bearing series, indicating a high-precision angular contact design with a 40mm bore, 62mm OD, and 24mm width. |
| C | 15° contact angle, optimized for supporting significant axial loads. |
| D | Indicates a duplex bearing (two bearings supplied as a set). |
| P4A | Specifies a high-precision tolerance class exceeding ABEC 7/ISO P4, ensuring minimal runout and vibration. |
| DB | Back-to-Back arrangement. This configuration provides high moment rigidity and excellent stability under complex loads. |
| CG | Specifies a Moderate preload (Class C) applied to the bearing set, enhancing rigidity and minimizing axial/radial play. |
| MM | Indicates the bearings are universally matchable (not supplied as a specific mirrored pair), offering flexibility in mounting configurations. |
71908 CD/P4ADBCGMM Bearing Structural Features & Performance Benefits
- High Rigidity & Stability: The duplex Back-to-Back (DB) arrangement creates a robust, preloaded system that significantly increases moment stiffness and resists operational deflection, making it suitable for applications requiring high positional accuracy.
- Superior Load Capacity: With a 15° contact angle and a dynamic load rating of 4478 lbf, this bearing set is engineered to handle substantial combined radial and axial loads from both directions effectively.
- Precision High-Speed Performance: The phenolic resin cage is lightweight and robust, contributing to lower centrifugal forces and smoother operation at the limiting speed of 56,000 rpm. The P4A tolerance class ensures minimal vibration for quiet, high-speed running.
- Optimized Material & Design: Manufactured from chrome steel for both rings and balls, the bearing offers high durability and fatigue resistance. The open seal type allows for efficient lubrication management in controlled environments.
71908 CD/P4ADBCGMM Bearing Typical Application Areas
This precision bearing set is ideally suited for high-performance applications where accuracy, speed, and rigidity are paramount. Key industries and equipment include:
- Machine Tool Spindles: High-speed milling, grinding, and turning centers.
- Precision Robotics: Arm joints and high-accuracy rotary axes.
- High-Frequency Motors and Spindles: Applications requiring minimal runout at extreme rotational speeds.
- Medical and Laboratory Equipment: Centrifuges and precision rotary devices.
- Aerospace Actuation Systems: Control surface mechanisms and other critical rotary assemblies.
