What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Standardized mechanical parts for fastening connections. Standard fasteners mainly include bolts, studs, screws, set screws, nuts, washers and rivets. There are many structural types of bolts, and most of the heads are hexagonal. For bolts subjected to shock, vibration or variable load, in order to increase flexibility, the polished rod part is made into thin sections or hollows. The seat end of the stud is screwed into the threaded hole of the connected piece, and the nut used at the nut end is similar to the bolt nut. The structure of the screw is basically the same as that of the bolt, but the shape of the head is various to adapt to different assembly spaces, tightening degrees and connection appearances. Set screws have different head and tip shapes to accommodate different levels of tightening. Nuts are also available in a variety of styles, with hexagons being the most widely used.
Align the four positioning holes 12-5 of the spring washer positioning plate 2 with the four positioning columns 4 of the screw tray 1, and place them on the screw tray 1. Several screws 5 are passed through the lower positioning plate 12-2 in turn. The spring washer hole 2-7, the opening slot 12-32 of the baffle plate 12-3, the inner ring of the spring washer 7 in the spring washer hole 2-7 of the upper positioning plate 12-1, hold the spring washer positioning plate 2 by hand The raised handle 12-31 of the baffle plate 12-3 pulls the baffle plate 12-3 out of the upper positioning plate 12-1 and the lower positioning plate 12-2, and several spring washers 7 pass through the holes on the lower positioning plate 12-2. The spring washer holes 2-7 fall down along the screw rod of screw 5, so that the screw rod of screw 5 penetrates into the spring washer 7, as shown in Figure 10, and then the spring washer positioning plate 2 is removed to complete the process of threading the spring washer.
Compared with the prior art, the beneficial effects of Guangdong Yueluo Hardware Industry Co., Ltd. are as follows: the square nut has a simple structure, strong practicability and good fastening effect, which changes the smooth plane design of the traditional square nut. There are circular protrusions, and strip protrusions and strip grooves are respectively provided at the two circular protrusions to increase the roughness of the contact surface of the nut, thereby effectively increasing the friction between the nut body and the fastener. , to achieve a good tightening effect.
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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