What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The side wall of the bolt hole is threaded, and the top of the nut is provided with several flattening notches. According to the locking nut of the preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the number of flattening notches is three. Due to the above features, the three flattening notches can be used as the focal point of the tightening tool, and the
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.
Screws and bolts are common connecting fasteners. The diameter of the thread is as small as less than one millimeter and as large as several hundred millimeters or even larger. The vast majority of threaded connections are pre-tightened during assembly in order to enhance the rigidity, tightness, anti-loosening ability of the connection and prevent the sliding of the bolted connection under lateral load. The pre-tightening force is determined according to the force of the bolt group and the working requirements of the connection. For important threaded connections, the preload must be measured and controlled.
For the detection of the shear force of the elastic cylindrical pin, the method and the tooling are marked, but the tooling is only a means to be used on the test bench, and the process of embedding the cylindrical pin into the tooling is a more difficult process. Generally, it is used to place the tooling on a plane, a vise, a simple V-shaped, and a simple U-shaped fixture. Originally, the elastic cylindrical pin was detected by hand or pliers to hold the cylindrical pin and align the pin with the outer cylinder of the tooling. Use a hammer to smash the shear holes, and adjust the concentricity of the inner and outer cylinders of the shear holes of the tooling from time to time. The limitations, dangers and difficulties of this assembly method are relatively large, often testing a set of cylindrical pins, which takes a lot of time and is difficult for lesbians to complete.
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