tailieunhanh - Giáo trình chế tạo ôtô - Phần 27

Tham khảo tài liệu 'giáo trình chế tạo ôtô - phần 27', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | CONTENTS c H A p T E R 27 Rolling Contact Bearings 1. Introduction. 2. Advantages and Disadvantages of Rolling Contact Bearings Over Sliding Contact Bearings. 3. Types of Rolling Contact Bearings. 4. Types of Radial Ball Bearings. 5. Standard Dimensions and Designation of Ball Bearings. 6. Thrust Ball Bearings. 7. Types of Roller Bearings. 8. Basic Static Load Rating of Rolling Contact Bearings. 9. Static Equivalent Load for Rolling Contact Bearings. 10. Life of a Bearing. 11. Basic Dynamic Load Rating of Rolling Contact Bearings. 12. Dynamic Equivalent Load for Rolling Contact Bearings. 13. Dynamic Load Rating for Rolling Contact Bearings under Variable Loads. 14. Reliability of a Bearing. 15. Selection of Radial Ball Bearings. 16. Materials and Manufacture of Ball and Roller Bearings. 17. Lubrication of Ball and Roller Bearings. Introduction In rolling contact bearings the contact between the bearing surfaces is rolling instead of sliding as in sliding contact bearings. We have already discussed that the ordinary sliding bearing starts from rest with practically metal-to-metal contact and has a high coefficient of friction. It is an outstanding advantage of a rolling contact bearing over a sliding bearing that it has a low starting friction. Due to this low friction offered by rolling contact bearings these are called antifriction bearings. Advantages and Disadvantages of Rolling Contact Bearings Over Sliding Contact Bearings The following are some advantages and disadvantages of rolling contact bearings over sliding contact bearings. 996 CONTENTS Rolling Contact Bearings 997 Advantages 1. Low starting and running friction except at very high speeds. 2. Ability to withstand momentary shock loads. 3. Accuracy of shaft alignment. 4. Low cost of maintenance as no lubrication is required while in service. 5. Small overall dimensions. 6. Reliability of service. 7. Easy to mount and erect. 8. Cleanliness. Disadvantages 1. More noisy at very high speeds. 2. .