Miniature Thrust Ball Bearings

Thrust-Ball-Bearingthrust1Thrust ball bearings consist of two precision SAE52100 chrome steel washers (rings) and a ball complement spaced by a retainer with brass but can also be manufactured in stainless steel (possibly subject to minimum requirements). Miniature thrust ball bearings (or axial bearings) are available with bore sizes as small as 2mm. Thrust bearings are used under purely axial loads. There are separate types of miniature thrust axial bearings with either flat races or washers incorporating a groove or raceway for heavier loads. They are supplied with ball grooves in the rings for increased capacity. The grooved type have one washer with a slightly larger bore to allow it to locate in the housing while the other washer has a smaller OD to locate on the shaft.

Miniature thrust bearings must be kept in matched sets. The bore (d dimensions) of one washer in the set will conform to the data in the above charts. The bore (d dimension) of the mating washer will be roughly .007″ larger, because it is a clearance hole for the shaft.

Thrust ball bearings also consist of two precision stainless steel washers (rings) and a ball complement spaced by a retainer with stainless steel.

The table below shows available bearings of the type you have selected. Basic dimensions and load ratings are given.

THRUST BALL BEARING: Dimensions in mm

Bearing No. BORE(d1) BORE(d2) OD(D1) OD(D2) Fillet Radius(r) Height(H) Dynamic Rating(Ca) kgf Static Rating(Coa) kgf Limiting Speed RPM: Oil Limiting Speed RPM: Grease
F2.5-6M
2.5
2.7
5.8
6.0
0.20
3.0
88
79
6,500
4,875
F2.6-6M
2.6
2.8
5.8
6.0
0.20
3.0
94
118
11,000
8,250
F3-8M
3.0
3.2
7.8
8.0
0.20
3.5
88
79
6,500
4,875
F4-9M
4.0
4.2
8.8
9.0
0.20
4.0
94
118
11,000
8,250
F4-10M
4.0
4.2
9.8
10.0
0.20
4.0
82
79
11,000
8,250
F5-10M
5.0
5.2
9.8
10.0
0.20
4.0
105
118
11,000
8,250
F5-12M
5.0
5.2
11.8
12.0
0.20
4.0
93
105
10,800
8,100
F6-12M
6.0
6.2
11.8
12.0
0.20
4.5
161
187
10,500
7,875
F6-14M
6.0
6.2
13.8
14.0
0.25
5.0
192
206
8,000
6,000
F7-15M
7.0
7.2
14.8
15.0
0.30
5.5
192
206
7,800
5,850
F7-17M
7.0
7.2
16.8
17.0
0.30
6.0
270
321
8,000
6,000
F8-16M
8.0
8.2
15.8
16.0
0.30
5.0
398
345
7,800
5,850
F8-19M
8.0
8.2
18.8
19.0
0.40
7.0
347
419
7,200
5,400
F9-17M
9.0
9.2
16.8
17.0
0.40
5.0
338
421
7,600
5,700
F9-20M
9.0
9.2
19.8
20.0
0.40
7.0
340
419
7,200
5,400
F10-18M
10.0
10.2
17.8
18.0
0.30
5.5
251
277
7,400
5,550

**Assumes adequate high speed oil or grease; and Dynamic Capacity (Ca)/applied axial load (Ca/Pa >= 12) is equal to or greater than 12

Shaft & Housing Tolerances:

  • Nominal Shaft Diameter: Min: +0.000; Max: -0.009
  • Nominal Housing Diameter: Max: +0.0051; Min: -0.000
Backup Shoulder Diameters:

  • Sufficient surface area is required to provide full support of the bearing rolling elements.
  • The minimum shaft and maximum housing shoulder diameters are as follows:
    • Shaft Shoulder Diameter Minimum = (Bearing ID (d1) + Bearing OD (D2))/2
    • Housing Shoulder Diameter Maximum = (Bearing OD (D2) + Bearing ID (d1))/2
Bearing O.D. Radial Runout: 8 µm Bearing Race Groove to Bore (d1) Radial Runout: 6 µm maximum Bearing Race Groove to Backface Axial Runout: 10 µm maximum
Lubrication:

  • The bearings must be lubricated either with oil or grease to perform satisfactorily and achieve it’s rated dynamic capacity.
  • It is the end user’s responsibility to provide for a final lubrication system.
  • For a nominal fee, it will lubricate the thrust bearing with an oil or grease selected by the end user.
  • Individual and special packaging is available upon request.
Bearing Preload: The larger of the two values from the equations below should be used as the minimum axial load to prevent ball sliding at relatively high speeds:

  • Fa min = (Coa/100) x (n/N max)2
  • Fa min = Coa/1000
    where
    Fa min: Minimum axial load (kgf)
    n: Speed (rpm)
    Coa: Basic Static Load Rating (kgf)
    N max: Limiting speed (oil lubrication) (rpm)
Bearing Life Calculations: Ln Life = (A1 x A2 x …) x (Ca/T)3 x 10

A1, A2, … Adjustment Factors:

  • Material
  • Lubrication
  • Temperature
  • Cleanliness/sealing
  • Mounting
  • Environment
  • Reliability

Ca = Dynamic Capacity Rating T = Applied Equivalent Dynamic Thrust Load