Study on Temperature Rise of Bearings After Grease Injection: Causes and Countermeasures

Proper grease injection is critical for bearing temperature control. The underlying influencing mechanism involves multiple variables, including grease quantity, type, distribution and working environment. Correct application of grease can greatly reduce friction and wear during bearing operation and maintain stable temperature. However, improper application will be counterproductive, raising temperature and damaging bearing service life. Below is an in-depth analysis of how grease injection affects bearing temperature rise:

Temperature Rise Caused by Excessive Grease

Increased rotation resistance: Excessive grease leads to excessive churning inside the bearing, raising rotation resistance and consequently increasing temperature.

Accelerated deterioration: Rising temperature speeds up grease oxidation, causing rapid aging. Separation of base oil hardens the grease, worsening lubrication and forming a vicious cycle.

Improper Filling Amount and Bearing Performance

Higher friction torque: Over-filled grease increases friction torque and pushes up bearing temperature.

Damaged sealing: Excess grease exerts extra pressure on seals, which may break the seal and allow impurities and moisture to invade and damage the bearing.

Uneven Grease Distribution & Local Overheating

Poor blending of new grease: Newly injected grease cannot mix and spread quickly, resulting in intensified local friction and temperature rise.

Necessity of running-in period: New grease requires a running-in phase. The initial rotating speed should be controlled at 30–60% of normal speed to avoid overheating caused by uneven distribution.

Wrong Grease Type and Lubrication Performance

Incorrect specification selection: Grease mismatched with bearing requirements will cause poor lubrication and temperature increase.

Contaminated or deteriorated grease: Degraded or contaminated grease loses its lubricating function, increases friction and triggers temperature rise.

Assembly Quality and Environmental Factors

Assembly defects: Improper bearing assembly, such as inappropriate clearance with end covers, may cause abnormal temperature rise.

Dirty working environment: Poor cleanliness of bearings and surrounding environment will negatively impact bearings, including temperature increase.

Negligence in Operation and Maintenance

Poor greasing skills: Improper greasing operation, such as wrong pressure control, may lead to overfilling or uneven grease distribution and trigger temperature rise.

Insufficient monitoring and maintenance: Lack of effective monitoring of bearing operating conditions may miss the chance to solve overheating problems timely.

Key Points

- Determine the proper grease filling volume to avoid overfilling or underfilling.

- Select matched grease grade to meet bearing requirements.

- Master correct greasing skills to prevent risks from improper operation.

- Conduct regular inspection and maintenance to keep bearings and surrounding area clean.

Conclusion

The quantity, type, distribution of grease and operating environment have profound impacts on bearing temperature. Following proper grease management strategies can effectively control bearing temperature and ensure reliable operation and long service life.