What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The grooved embedded parts are usually connected by bolts, and there are many types of T-bolts used with the grooved embedded parts. position, so that the T-bolt can form a stable connection with the groove-type embedded part, but in the actual installation process, the T-bolt pressed into the groove-type embedded part is prone to loosening problems, so it is difficult to better Fixed in trough embedded parts.
At present, for roller or needle roller bearings without cages, ribs, and low-speed operation, the structure mainly includes inner and outer rings and rollers or needle rollers in the raceway between the inner and outer rings, and additional The retaining rings on both sides of the roller or needle roller, among which the retaining rings added on both sides of the roller or needle roller are annular steel sheets punched from metal sheet, and their function in the bearing is only Correctly guide the rollers or needle rollers to run normally in the raceway between the inner and outer rings to prevent the rollers or needle rollers from deviating and slipping out of the raceway. The defect of the retaining ring of this structure is that first, because the rigid retaining ring and the inner ring are completely separated, there is a gap between the retaining ring and the installation shaft during installation. When the bearing is working, The retaining ring is driven by the outer ring and the rollers or needle rollers to rotate around the installation shaft. Due to the inconsistency of the structure, the retaining ring is easy to fall off during the rotation process, the safety of use is poor, and the rollers or needle rollers will appear toward the raceway. The situation of one side offset, which causes the bearing load center to offset, affects the reliability of the bearing operation, and ultimately affects the service life of the bearing; There is a gap between the raceways of the needle, so the tidbits, dust, etc. generated during the working process will continue to enter the raceway between the inner and outer rings. It is stuck; in addition, due to the gap between the steel retaining ring and the raceway, the grease stored in the raceway will be continuously lost, which will cause the bearing to heat up due to frequent lack of grease, or even burn out, which also affects the to the service life of the bearing.
The existing way to achieve radial locking of the shaft is generally to sleeve the positioning block on the shaft, and then use a cylindrical pin to pass through the positioning block to lock the shaft. The locking structure and method are as follows: A locking groove with an arc-shaped cross-section is set on the outer side of the shaft along the direction perpendicular to the axis of the shaft, an opening is set on the positioning block, and then a cylindrical pin is used to pass through the positioning block from the outside of the positioning block and screw the lock at one end of the cylindrical pin. When the lock nut is tightened, the opening on the positioning block will be deformed inwardly and locked on the shaft.
However, Yueluo still feels that there should be room for improvement for the screw improvement and screw that integrates stability, labor, fast and multi-function in the above two cases; for example, No. 556784 screw improvement Although the rod has the function of cutting and collecting chips, when the screw starts to screw into the object such as wood, it is hindered by the hardness of the object's tissue, so the staff still needs to exert considerable force, resulting in the lock. In the solid operation, there is still a lack of difficulty in screwing in operation; another example, new cases such as No. 289408 screw that integrates locking, stability, labor, fast and multi-function, although the rod has the structural function of cutting and chip removal, it is The rod part is screwed into the middle section to the rear section of the object. Since the debris cannot be discharged, the rod part pushes the outer part of the object to the surrounding tissue of the object, so that the object expands outwards and even seriously damages the appearance of the object.
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