What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
At present, due to the installation position determined in the design process of the traditional thrust cylinder in China, the corresponding position of the piston rod and the clamping arm is fixed, and it is impossible to ensure that the workpiece can be clamped while the workpiece is thin. It is not conducive to the use of such products when clamping. Secondly, when the workpiece is assembled or welded, it not only needs to be tightened in a certain direction, but also needs to be positioned, so as to ensure the accuracy required for processing. When a workpiece is fixed in this way, it must be realized by adding a mechanism, which will increase the complexity of the system and bring inconvenience to installation and maintenance.
As we all know, screws and nuts are widely used in various mechanical equipment as connectors, so that the mechanical equipment can be easily disassembled, but for equipment whose internal structure needs to be kept secret, it generally does not need to be disassembled after assembly. The nut can be easily dismantled, leaving equipment that needs to be kept secret of the internal structure from being kept secret.
Blind rivets (blind rivets) --------- rivet body (rivet body) mandrel (rivet stem or rivet mandrel). It is a type of rivet for single-sided riveting, but it must be riveted with a special tool - a rivet gun (manual, electric, pneumatic). When riveting, the rivet core is pulled by a special rivet gun to expand the rivet body and play a riveting role. This type of rivet is especially suitable for riveting occasions where it is inconvenient to use ordinary rivets (riveting from both sides), so it is widely used in construction, automobiles , ships, aircraft, machinery, electrical appliances, furniture and other products. Among them, the open-type oblate head blind rivets are the most widely used, the countersunk head blind rivets are suitable for riveting occasions where the surface needs to be smooth, and the closed blind rivets are suitable for riveting occasions that require high load and certain sealing performance.
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.
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