This bearing is manufactured from SUS420 martensitic stainless steel and is designed specifically for applications requiring high rotational speeds within extremely limited spaces. Its standout feature is a thin-walled structure; while retaining the fundamental load-bearing capacity of deep-groove ball bearings, the 68 series significantly reduces radial cross-sectional dimensions, thereby effectively lowering the overall weight and rotational inertia of the assembly.
Bearing Features
Thanks to the high-carbon 420 material and a precision quenching process, the bearing achieves a hardness exceeding HRC50, demonstrating excellent wear resistance and compressive strength. In terms of performance, the series offers low starting torque and high rotational precision, making it ideal for use in precision medical devices, micro-fans, and precision encoders. It provides superior rust resistance compared to standard chrome steel, ensuring stable long-term operation in moderately humid or condensing environments, while the tight fit between the inner/outer rings and rolling elements guarantees low-noise performance during high-speed operation.
Technical Specifications
| Bearing Reference | Boundary Diameters | Basic Dynamic | Basic Static | Limiting Speeds | ||||||||||
| Flange | Open | Shield | d mm |
D mm |
Df mm |
B mm |
Bf mm |
B1 mm |
Bf1 mm |
rsmin mm |
Cr(kN) | Cor(kN) | Grease | Oil |
| F | S681 | - | 1 | 3 | 3.8 | 1 | 0.3 | - | - | 0.05 | 0.074 | 0.02 | 16.5 | 18.5 |
| F | S682 | ZZ | 2 | 5 | 6.1 | 1.5 | 0.5 | 2.3 | 0.6 | 0.08 | 0.167 | 0.049 | 9.4 | 10.6 |
| F | S683 | ZZ | 3 | 7 | 8.1 | 2 | 0.5 | 3 | 0.8 | 0.1 | 0.314 | 0.108 | 6.6 | 7.4 |
| F | S684 | ZZ | 4 | 9 | 10.3 | 2.5 | 0.6 | 4 | 1 | 0.1 | 0.637 | 0.225 | 5.1 | 5.7 |
| F | S685 | ZZ | 5 | 11 | 12.5 | 3 | 0.8 | 5 | 1 | 0.15 | 0.715 | 0.284 | 4.1 | 4.6 |
| F | S686 | ZZ | 6 | 13 | 15 | 3.5 | 1 | 5 | 1.1 | 0.15 | 1.08 | 0.441 | 3.5 | 3.9 |
| F | S687 | ZZ | 7 | 14 | 16 | 3.5 | 1 | 5 | 1.1 | 0.15 | 1.18 | 0.51 | 3.1 | 3.5 |
| F | S688 | ZZ | 8 | 16 | 18 | 4 | 1 | 5 | 1.1 | 0.2 | 1.25 | 0.588 | 2.8 | 3.1 |
| F | S689 | ZZ | 9 | 17 | 19 | 4 | 1 | 5 | 1.1 | 0.2 | 1.32 | 0.666 | 2.5 | 2.8 |

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