Put some rotating bodies (rollers, rollers, or rolling stitches) between the inheritance and motion parts, so that the two -matching rails that are not directly contacted are called rotating guide rails.
The characteristics of rotating rails are that the friction resistance is small, the exercise is light and flexible; the wear is small, which can maintain accuracy for a long time; the coefficient of movement and static rubbing is small, and the phenomenon of "crawling" is not easy to occur at low speed, so the exercise is uniform and smooth. Therefore, on the device that requires micro -volume movement and precise positioning, the disadvantage of the increasingly extensive use of rotating guide rails is that the guide rail surface and rotation are point contact or line contact, poor vibration resistance, and large contact stress. High surface hardness requirements: High requirements for the shape accuracy of the guide rail and the size of the rotation body.
1. Structure form
Rolling rails-is the roller guide rail of the V-flat-crossing section, the roller guide rail of the double V-shaped cross-section, and the circular cross-section roller rail. Because the roller and the rail surface are contact, the exercise is lightweight, but the rigidity is low, and the carrying capacity is small. Commonly used in occasions with small weights and loads.
The roller rail-The roller in the roller rail is contact with the guide rail. Therefore, its bearing capacity and stiffness are greater than the rolling bead guide, the abrasion resistance is better, and the flexibility is slightly worse. The roller is more sensitive to the unevenness of the guide rail, and it is easy to generate side offset and sliding, which increases the resistance of the guide rail, accelerates wear, and reduces accuracy. The larger the diameter of the roller, the more sensitive it is.
When the structure size is limited, a roller with a small diameter can be used. This guide is called a roller guide rail. The rolling guide rail support is a standard component, which has the advantages of installation, simple lubrication, and easy to adjust protection. Because the roller rotates in the closed track, it can be used on a large guide track.
2. The general topic of rotating rail design
1. Selection of structural form: Rotating guide rails are divided into two types: open and closed according to their structural characteristics. The open -type rotating rail is used in the middle of the two guide loads, and it can maintain a good contact rail in the middle of the two guide rails. The closed guide rail is the opposite. The flexibility of the ball guide rail is good, the structure is simple, the manufacturing is easy, but the loading capacity is small, the stiffness is low, and it is often used in occasions with high accuracy requirements, flexible exercise, and light load. The roller (needle) guide rail has a large rigidity and strong carrying capacity, but the position accuracy is high. The rotating rail adopts a standard rotor bearing. The structure is simple, the manufacturing is easy, and the lubrication is convenient. It should be used for medium -precision occasions. In order to increase the bearing capacity of the rotating rail, the pre -load can be applied. At this time, the rigidity is large, and there is no gap, and the accuracy improves accordingly, but the damping is larger than that of the pre -load, the manufacturing is complex, and the capital is high. Therefore, it is mostly used for precision guide rails.
2. Selection length: Generally, the length of the guide rail should be as short as possible under the conditions of meeting the rail movement.
When using a circular rotating guide rail support, the itinerary length of the motion parts is not limited. The size and number of rotating bodies: Large diameter, large loading capacity, and small friction resistance. For the roller rail, the diameter of the roller is increased and the stiffness increases (the stiffness of the roller rail has nothing to do with the diameter of the roller). Therefore, if it is not limited by structure, a large size rotation should be selected. The friction resistance of the roller rail is large, and the rolling needle may develop. Therefore, when the number of roller rails (especially when the diameter of the rolling needle is less than 4 mm) is not used as possible, when the number of rotor is increased, the carrying capacity and stiffness of the guide track also increase. However, the number of rotation should not be too much. Too much will increase the unevenness distributed on the rotor on the rotor, and the stiffness will decrease. If the number of rotation is too small, the manufacturing error will significantly affect the orientation accuracy of the motion parts. Generally, the number of rotation is 12 in one rotation.
Structure of a linear guide rail
Third, rotating guide rail rigidity and pre -tightening method:
1. When the workbench moves back, the pressure on the rotation of the workbench will change. When the guide rail is at 1, the rotation of both ends is equal, and the workbench is kept horizontally: When the guide rail moves to the position 1 or i, the turning force of the two ends is different, and the deformation is inconsistent. This causes errors.
2. In order to reduce the deformation of the guide rail and improve the stiffness, in addition to the tolerance of the shape, size, number, number, and appropriate increase in the thickness of the workbench, the commonly used pre -load method to improve the rigidity of the guide rail. The tour tail -shaped rotation rail is obtained and controlled by the mobile rail panel. The test confirmed that as the over -profile increased, the rigidity of the guide rail began to increase sharply. After reaching a certain degree, the over -profit volume was increased. The change is not large, and the over -profit volume exceeds a certain value, and it has increased sharply. Therefore, the fairness of the fairness should make the rail rigidity better and the traction is not large.
Fourth, technical requirements
The quality of the guide rail depends on its manufacturing accuracy and installation accuracy. Several technical conditions for rotating rails should be formulated according to the requirements of the use.
The non-straightness of the guide rail is generally 10-15 microns, and the precision is less than 10 microns. The diameter of the rotation body is poor. For the general guide rail, the diameter difference between all the rotation bodies is not greater than 2 microns. The diameter difference between the rotating band is not greater than 0.5 microns: the taper of the roller is within the length of the roller, and the diameter of the size is less than 0.5-1 Microfine: surface smoothness should be scraped: within 25x25 cm 2, its contact spots are 20- 25 points, precisely take the upper limit, and generally remove the limit.
