What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
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 use of the screw is mostly used in plastic molding equipment, such as plastic profile extruders, injection molding machines, etc. Screw and barrel are the core components of plastic molding equipment. It is the part of heating extrusion plasticizing. It is the core of plastic machinery. Screws are widely used in machining centers, CNC machines, CNC lathes, injection molding machines, wire cutting machines, grinding machines, milling machines, slow wire walking, fast wire walking, PCB drilling machines, engraving machines, engraving and milling machines, spark discharge machines, tooth bite machines , planer, large vertical lathe gantry milling, etc.
The advantage of wood screws is that the consolidation ability is stronger than that of nails, and they can be removed and replaced, which is more convenient to use without damaging the wood surface. This is a kind of nail specially designed for wood, and after entering the wood, it will be embedded in it very firmly. If the wood is not damaged, it is impossible to pull it out, and even if it is pulled out forcibly, it will bring out the nearby wood. Another point to note is that the wood screws must be screwed in with a screwdriver. Never knock them in with a hammer, as it will damage the surrounding wood. A screwdriver is a tool for loading and unloading wood screws. The shape matches the groove shape of the wood screw head, and there are two types: one-word and cross-shaped. In addition, there is a special screwdriver installed on the bow drill, which is suitable for loading and unloading large wood screws. Convenient and labor-saving. [2]
A T-bolt. This kind of bolt includes a bolt shank and a bolt head, and the bolt head adopts a special cylindrical bolt head, which can be suitable for installation and cooperation of various sizes. Although the shape of such a bolt head is greatly improved compared to the square bolt head in the prior art, the cylindrical bolt head is particularly inconvenient to install, and special installation tools must be used for installation. If the manual direct installation method is adopted, since the force area of the finger touching the side of the cylinder is small, it will increase the difficulty of the installation work and needs to be improved.
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