Installation Methods and Cautions of miniature bearings

The installation of miniature bearings (outer diameter less than 9mm) requires special attention to cleanliness, even force application, and specialized tools. The main methods include cold installation, hot installation, and hydraulic assistance to prevent contaminant intrusion and mechanical damage.

ØPreparation Before Installation

①　Environment Cleaning: Operate in a dry, dust-free area, away from sources of metal debris; wipe the shaft and bearing housing with a clean cloth to remove burrs or rust.

②　Dimensional Check: Verify shaft and bearing housing tolerances, ensuring mating surfaces are flat; sealed bearings should not be cleaned.

③　Tool Preparation: Have a sleeve, hydraulic press, or induction heater readily available; wear protective gloves.

ØInstallation Method

①　Cold Installation (Suitable for small interference fits): Use a sleeve to evenly tap the end face of the bearing rings, avoiding direct hammering or applying force to the rolling elements.

②　When installing inner and outer rings simultaneously, ensure even pressure and flush tool contact surfaces.

③　Hot Mounting (for larger interference fits): Heating temperature ≤120°C (≤80°C for sealed bearings). Use an oil bath or induction heater for uniform heating, avoiding localized overheating. Install immediately after heating to prevent cooling.

④　Hydraulic Assist: Hydraulic nuts or oil injection method (high-pressure oil film reduces friction), suitable for tapered bore bearings. For miniature bearings, a press is preferred, applying force through an inner ring pressing tool.

ØPrecautions:

①　Force Application Principle: Force should only be applied to the mating rings (inner ring for shaft mounting, outer ring for housing). Do not strike the cage or seals.

②　Sealing Treatment: Sealed bearings cannot be cleaned; grease-lubricated bearings should retain the anti-rust layer.

③　Contamination Prevention: Check clearance and runout after installation; contaminants are a major cause of failure and require regular maintenance.‌‌