Linear Rolling Bearings University of Utah（线性滚动轴承犹他大学）.pdf

Linear Rolling Bearings ME EN 7960 – Precision Machine Design Topic 8 ME EN 7960 – Precision Machine Design – Linear Rolling Bearings 8-1 Bearings • Bearings are mechanical elements that free one or more of the six degrees of freedom while constraining the remainders • Bearings can be classified in two main ways 1. Degrees of freedom (linear, rotary) 2. Contact yes or no (contact, non-contact) ME EN 7960 – Precision Machine Design – Linear Rolling Bearings 8-2 1 Non-Contact Bearings • Non-contact bearings maintain a gap between the moving surfaces, thereby avoiding any kind of contact • The gap is maintained through: – Pressurized medium (air, water, oil) – External forces (magnetic forces) • Non-contact bearings are used in precision machinery where accuracy and speed requirements prohibit the use of contact bearings – Hydrostatic: high-speed machining spindles – Aerostatic: slides for coordinate measuring machines (CMM), dental drills. Also: read head of hard disks. – Magnetic bearings: high-speed trains (Transrapid) ME EN 7960 – Precision Machine Design – Linear Rolling Bearings 8-3 Contact Bearings • Contact bearings can be grouped in two main categories according to their type of contact: 1. Rolling contact bearings 2. Sliding contact bearings • Rolling contact bearings separate the mechanical components through the use of balls or rollers • Sliding contact surfaces make contact, either with or without lubrication ME EN 7960 – Precision Machine Design – Linear Rolling Bearings 8-4