7208CTRDFDMP4
Main technical Specifications
Detailed parameters and installation dimensions:
| Part Number | 7208CTRDFDMP4 |
| Cage | TR = Phenolic resin, Outer ring guided |
| Preload | M = Medium Preload |
| DFD Preload - M | 1362.72 N | 306 lbf |
| Temperature - T(min) | -30 °C |
| Temperature - T(max) | 120 °C |
| Seal | Open type |
| Inner and outer ring Material | GCr15SiMn |
| DFD Axial Rigidity - M | 266.4 N/µm |
| Balls Material | GCr15SiMn |
| Bearing Type | High-Accuracy Angular Contact Ball Bearings, Standard Series |
| Speed ratings (grease) - nB | 18803 min–1 |
| Speed ratings (oil) - nG | 28802 min–1 |
| Dimension series | 2 = 02 Series |
| Series | 72 series (72..CTRDFDMP4) |
| Bore | Cylindrical |
| Dimension Inside - d φ | 40 mm | 1.5748 inch |
| Dimension Outside - D Φ | 80 mm | 3.1496 inch |
| Dimension Width - B | 18 mm | 0.7087 inch |
| Units | Metric |
| Load | Axial |
| Dimension Chamfer - r min | 1.1 mm | 0.0433 inch |
| Dimension Chamfer - r1 min | 0.6 mm | 0.0236 inch |
| Manufacturer Part Code | 7208C TR DFDM P4 |
| Rows NO. | One |
| Permissible Axial Load | 16982 N | 3817 lbf |
| Factor - fo | 14.1 |
| Effective Load Center - a | 17.0 mm | 0.6693 inch |
| Accuracy class | P4 = (ABEC-7 / ISO Class 4) |
| Arrangement | DFD = Three set (>><) |
| Radial Dynamic Capacity - Cr | 37267 N | 8377 lbf |
| Radial Static Capacity - C0r | 24317 N | 5466 lbf |
| Abutment Dimensions Shaft - da min | 47 mm | 1.8504 inch |
| Abutment Dimensions Housing - Da max | 73 mm | 2.8740 inch |
| Abutment Dimensions Housing - Db max | 75 mm | 2.9527 inch |
| Design type | 7 = Standard High-Accuracy |
| Contact angle - α | C = 15 ° |
| Fillet Radius - ra max | 1 mm | 0.0394 inch |
| Fillet Radius - rb max | 0.6 mm | 0.0236 inch |
| Measured Axial Clearance - M | -29 µm |
| Bearing DFD Mass - m | 1.098 kg | 2.4207 lb |
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7208CTRDFDMP4 refers to a type of 72 series (72..CTRDFDMP4) High-Accuracy Angular Contact Ball Bearings, Standard Series, with dimensions 40 mm (Bore) x 80 mm (OD) x 18 mm (Width), designed for High speed, ultra-precision, high rigidity, low operating friction, and long service life, primarily used in CNC machine tool spindles and other high-precision machinery, Its normal operating speed can reach: the grease speed ratings: 18803 rpm, oil speed ratings: 28802 rpm, featuring One (row) construction, TR = Phenolic resin, Outer ring guided retainer to ensure extended service life, advanced Open type, for applications the field of precision machinery, especially high-speed and high-precision spindle systems, requiring high running accuracy and the accommodation of radial and axial loads simultaneously.. it's built to handle significant loads (dynamic radial: 37267 N, static radial: 24317 N, ), It weight approximately 1.098 kilogram.
- Min. Order: 1 Piece/(7208CTRDFDMP4, 40 = ID, 80 = OD, 18 = B, 1.098 kg) or according to different suppliers
- Price: Different brands, different quality, different 7208CTRDFDMP4 prices, different suppliers and different quality determine different prices, you can ask the supplier in detail for the price according to your own needs.
- Precision Rating: DIN: P2~P0; ANSI: ABEC9~ABEC1; JIS: JIS~JIS0; ISO: CLASS2~NORMAL CLASS; GB/T30794 B~G
- Inquiry ways: The right of the inquiry form, Email, skype, Whatsapp
Data Transfering...
✨What are the Benefits of choosing 7208CTRDFDMP4 bearings?
🏭 What are the applications of the 7208CTRDFDMP4 bearing?
📐 How should choose the right model for a Angular contact ball bearings, super-precision?
Selecting ultra-precision angular contact ball bearings can be summarized in three steps: choose the series, match the angle, and select the suffix.
Step 1: Choose the Series – Determine the product line based on the operating conditions.
Several dedicated series are designed for different applications; you can directly choose the appropriate one:
Robust Series: General purpose preferred. Suitable for general machine tool spindles such as machining centers. Low heat generation, high speed; models with seals can extend grease life to 1.7 times that of open bearings. BNR: 18° high-speed type, and BER: 25° general-purpose type.
Standard Series (70/72/79): Conventional precision, high cost-effectiveness. Suitable for general precision machinery and lead screw supports; optional seals can increase grease life by 1.5 times.
SpinShotⅡ Series: Dedicated for electric spindles. Optimized oil-air lubrication; NT#40 level can reach 40,000 min⁻¹, with noise reduction of 3-5dB.
BSR Series: Dedicated for small diameters (inner diameter ≤25mm). Suitable for small ultra-high-speed spindles and internal grinding spindles. TAC-F Series: Dedicated for heavy-duty cutting. 50° contact angle, highest rigidity, suitable for heavy cutting and high-rigidity shaft applications.
BNRD/BERD series (ROBUSTDYNA): Higher rigidity and load-bearing capacity than the BNR/BER series, suitable for applications such as machining center spindles. BNRD: 18°, BERD: 25°
Step 2: Understanding the Angle Designation
The contact angle determines axial load capacity and high-speed performance. Different series have different designations:
Standard series, C: 15° (ultra-high speed), A5: 25° (general purpose, most commonly used), A: 30° (medium load), and B: 40° (heavy load).
Robust series, BNR: 18° (Robust high-speed type), BER: 25° (Robust general purpose type), and BSR: 15° (Robust small diameter type).
BNRD/BERD series (ROBUSTDYNA): BNRD: 18° (Ultra-high speed, low heat generation), BERD: 25° (High speed + high rigidity, better load-bearing capacity).
The selection principle is that a smaller contact angle is more suitable for high speeds, while a larger contact angle allows for stronger axial load resistance.
Step 3: Matching the Suffix – Locking in the Complete Model Number
Bearing Type①⑥
① 7: High-Accuracy Angular Contact Ball Bearings (Standard Series)
⑥ High-Speed Angular Contact Ball Bearings (ROBUST Series)
BNR,BER: BASIC Series
BNRD,BERD: ROBUSTDYNA
BSR: MINI Series
Contact Angle④⑥
④ Standard Series (C: 15° A5: 25° A: 30°)
⑥ ROBUST Series (BNR,BNRD: 18°, BER,BERD: 25°, BSR: 15°)
Dimension Series②⑦
② Standard Series (9: 19 Series, 0: 10 Series, 2: 02 Series)
⑦ ROBUST Series (19: 19 Series, 29: 29 Series, 10: 10 Series, 20: 20 Series, 02: 02 Series)
Bore Number③⑤
③ Standard Series
Up to 3: Bore diameter 00: 10mm, 01: 12mm, 02: 15mm, 03: 17mm
4 and above: Bore diameter = Bore number x 5 (mm)
⑤ ROBUST Series
Nominal bore diameter = Bore dimension (mm)
⑧ Material
Standard Series (No code: Steel ball SN24: Seramic ball)
ROBUST Series
S Type: Inner and outer ring use Bearing steel (SUJ2), Balls use Bearing steel (SUJ2)
E Type: Inner and outer ring use Bearing steel (SUJ2), Balls use Ultra long life rolling elements (EQTF)
H Type: Inner and outer ring use Bearing steel (SUJ2), Balls use Ceramic (Si3N4)
J Type: Inner and outer ring use Ultra Long life steel (SUJ7), Balls use Ceramic (Si3N4)
X Type: Inner and outer ring use Heat resistant steel for highspeed operation (SHX), Balls use Ceramic (Si3N4)
XE(SpinshotⅡ) Type: Inner and outer ring use Heat resistant steel for highspeed operation (SHX), Balls use Ceramic (Si3N4)
⑩ Lubrication Holes
No code: No lubrication holes E34: Direct lubrication bearing
⑨ Cage
T = phenolic resin cage, inner ring guided
T1X = polyamide resin cage, ball guided
TA = Phenolic resin, Outer ring guided
TR = Phenolic resin, Outer ring guided
TSR = PPS resin, Outer ring guided
TX = Phenolic resin, Outer ring guided
TYA = polyamide resin cage, ball guided, high speed
TYN = Polyamide resin, Ball guided
MY = Brass, ball guided
⑪ Seal
No code: Open type V1V: Non-contact rubber seal
⑮ Accessories
+Y3: O-ring on bearing outside surface Available for ROBUST direct lubrication bearings (E34) only.
⑫ Arrangement
DU is a universal pairing of two rows; DB is back-to-back; DF is face-to-face; DT is tandem.
⑬ Preload
EL: Extra Light Preload
L: Light Preload
M: Medium Preload
H: Heavy Preload
CP: Special Measured (–) Axial Clearance
CA: Special Measured (+) Axial Clearance
⑭ Accuracy
P2: ISO Class 2
P4: ISO Class 4
P5: ISO Class 5
P3W: Special class (Special tolerances for deviation of inner/outer ring width, others are P3)
P3: Special class (ISO Class 4 dimensional tolerances and ISO Class 2 running accuracy)
P4Y: Special class (Special bore and outside diameter tolerances, others are ISO Class 4. See figure on left.)
⑯ Grease Brand
Grease typically used in machine tool spindles:
MTR: ROBUSTGRD MTS: MTS grease
⑰ Grease Quantity
X: 15% of internal space K: 20% of internal space L: 30% of internal space
Three-step selection process: Determine the series → Select the contact angle → Match the suffixes (cage + material + seal + preload + arrangement + precision). Following this logic will allow you to select the complete NSK ultra-precision angular contact ball bearing model.
🛠️ What is the mounting procedure for 7208CTRDFDMP4 bearings?
Cleaning and Inspection: Clean the bearing in a dust-free environment. After a rough wash to remove contaminants, perform a fine wash until the bearing feels smooth and responsive to the touch. Simultaneously check the accuracy of the mating surfaces of the shaft and bearing housing.
Measurement and Fitting: Precisely measure the bearing's inner and outer diameters. Mark the corresponding positions on the shaft and housing bores for alignment during assembly to compensate for any deviations.
Installation and Positioning: Apply pressure evenly using a specialized tool, focusing only on the interference fit rings. If heat fitting is used, tighten the inner ring during cooling to prevent clearance from affecting the preload.
Preload Adjustment: When installing in pairs, ensure the parallelism of the inner and outer spacers is ≤1μm. Adjust the preload force to the specified value by grinding the spacers.
Lubrication Inspection: Add the specified amount of grease or oil mist lubricant. After installation, manually rotate the bearing to check its flexibility and operating noise.
📋 Special Note for mounting 7208CTRDFDMP4 bearings?
Clean Environment: Operation must be performed in a dust-free cleanroom with humidity ≤65% to prevent dust and impurities from affecting accuracy.
No Striking: Direct striking of the bearings is strictly prohibited. Special tools must be used, and force must be applied evenly.
Matching Marks: Bearings used in pairs are not interchangeable. Installation must strictly follow the factory matching marks.
Rust-Proof Storage: Long-term storage requires regular rust-proofing treatment. Maintain ventilation and avoid corrosive gases.