Introduction
A guide rail is a component that supports and guides a moving member along a specific trajectory. It is also commonly referred to simply as a guide rail pair.
The moving parts can move along straight lines, circles, or curves. Circular rolling guides can be used for rolling thrust bearings, while curved guide rails are not often used in machinery.
Guide rails are a crucial component in machinery, particularly in machine tools. The accuracy of a machine tool is closely tied to the accuracy of its guide rail. In small-batch precision machine tools, the machining work on the guide rails can account for up to 40% of the total machining workload.
Damage to the guide rail can also make maintenance difficult.
Based on the principle of kinematics, the guide rail is a device that restricts a moving member to only one degree of freedom.
The guide rail pair consists of a static guide rail, which is the guide surface disposed on the support member and is relatively long, and a movable guide rail, which is disposed on the moving member and is relatively short.
The moving member with the movable rail is often referred to as the worktable, sliding table, and has a plane or circular arc surface.
When a circular arc guide surface is combined with a cylindrical guide rail and different flat guide rail faces form a friction between rectangular guide rail faces, it is called a sliding guide rail. If a rolling element is placed between the guide rail faces to convert friction into rolling friction, it is called a rolling rail.
Guide rails come in both closed and open styles. Closed rails can handle overturning moments, while open rails cannot.
Working principle
(1) According to the nature of work, guide rails can be divided into three categories:
Main Motion Guide: This type of guide rail is used for high speed main motion of the moving rail seat. The relative speed between the rail pairs is high.
Feed Motion Guide: This type of guide rail is used for low speed feed motion. The relative movement speed between the rail pairs is low.
Displacement Rail: This type of guide rail is only used to adjust the relative position between parts, with no relative movement during processing. An example of this type of guide rail is the guide rail for the tailstock of a lathe.
(2) According to the nature of friction, guide rails can be divided into several categories:
Sliding Rail: This type of guide rail has sliding friction between the auxiliary working faces of the guide rail.
Hybrid Friction Guide: This type of guide rail has a combination of sliding and other types of friction.
Boundary Friction Guide: This type of guide rail has friction at the boundary between the auxiliary working faces of the guide rail.
Hydrodynamic Guide: This type of guide rail has friction that is generated by the movement of a fluid, such as oil.
Hydrostatic Guide: This type of guide rail has friction that is generated by the pressure of a fluid, such as oil.
Rolling Friction: This type of guide rail has rolling bodies between the auxiliary working faces of the guide rails, resulting in rolling friction between the two rail faces.
Rolling Guide: This type of guide rail is a type of rolling friction guide.
Roller Guide: This type of guide rail has rolling elements, such as rollers, between the auxiliary working faces of the guide rail.
Needle Guide: This type of guide rail has needle-like rolling elements between the auxiliary working faces of the guide rail.
(3) According to the force situation, guide rails can be divided into two categories:
Open Rails: These are guide rails that rely on external loads and the weight of components to keep the two rail faces in place.
Closed Guide Rail: This type of guide rail uses a pressure plate to support the main guide surface, ensuring stability.
(4) According to the movement trajectory, guide rails can be divided into two categories:
Circular Motion Guide: This type of guide rail has a relative movement of the guide rail pair in a circular trajectory, such as the faceplate and base rail of a vertical lathe.
Linear Motion Guide: This type of guide rail has a relative movement of the guide rail pair in a straight line, such as the slide of an ordinary lathe and the bed rail.
