The basic structure of a sliding guideway consists of a guideway (also known as a shaft or track) and a movable body (also known as a bearing) that constrains the trajectory of motion, and requires the following properties:
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1. Support the weight of the movable body;
2. Small and stable moving force;
3. Even under the conditions of high-speed motion and emergency stop motion, it can stably guarantee the guiding accuracy for a long time.
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1 and 2 are static performance (performance without motion), and 3 is dynamic performance (performance with motion). When performing structural design and selection of sliding guide rails, basic knowledge related to the following items is required.
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Here, we will explain typical linear slide rails, rotary guide rails and curved guide rails.
(1) Linear slide rail
The linear slide rail is a mechanism that converts the motion of the cylinder and other driving devices into high-precision linear motion with relatively small frictional resistance. There are three typical types of linear slides (see [Figure]).
Types of Linear Slides
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FA Machinery
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Linear guide with round rod ([Fig.] a, b)
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· If no rotation is required, a single structure can be used
·The guide rail is thickened to support the movable body
·Anti-friction mechanism can be added
*Linear Bushing
*Oil free bushing
*Clamp bushing
*Complete set of miniature ball guide rail
Linear sliding guide (guide rail) ([figure] c)
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·Low friction, high rigidity, high precision and other properties can be selected.
*Linear Guides
*Linear slide
*Sliding table
Planar Constraint Rails (Plane Support, Triangular Rails)
([Figure] d, e)
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・Because of the small number of parts, various performances such as inexpensive mechanism and ultra-high precision guidance (#) can be realized.
*Linear Guides
*guide
(#: air bearing guide, etc.)
(2) Rotating guide rail
The rotary guide (ball bearing) that supports the rotating shaft also uses the same concept as the guide above. However, although inertial forces can act on linear motion, they cannot act on rotary motion, and ball bearing technology has been greatly developed due to the special need for guidance characteristics during high-speed rotation.
(3) Curved guide rail
The slide rail with curved (arc curve, etc.) movement is to make the track of the linear slide guide into a curved shape, and use an ultrasonic motor as the drive motor.
2. Sliding guide rail and friction and wear
Friction occurs when solids touch each other and move. If this friction is not properly treated with lubricating oil, it can lead to the following problems.
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1. Sintering due to friction between solids;
2. Abrasion occurs and becomes increasingly severe;
3. Increased power loss.
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Therefore, it is very important to properly control friction and wear.
(1) About friction
The types of friction include the following two types:
a) Sliding friction
b) rolling friction
Sliding friction is the form of friction that occurs on planar restraint rails, skis, skis, etc.
[Picture] It is a mural painting in ancient Egypt. It shows how a large stone statue is carried on a sled. The 1 guy in the middle can be seen pouring oil on the front of the skid to reduce friction.
