What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The fixing screw proposed by Guangdong Yueluo Hardware Industry Co., Ltd. has a screw body 1, and the axial surface of the screw body 1 is formed with extending screw teeth 6, and the axial surface is a column along the central axis direction of the cylinder of the screw body 1. The body surface has a hemispherical screw tail 7 at the bottom, and a screw head 2 at the top. The upper surface of the screw head 2 is provided with a slot (not shown). The screw body 1 is composed of the upper tapered rod 4 and the lower cylindrical screw 5. The tapered rod 4 is an inverted cone, the diameter of its circular upper surface and the diameter of the screw mounting hole 10. equal. The fixing screw also has a washer 3, the washer 3 is arranged between the screw head 2 and the screw body 1, the lower surface of the cylindrical washer 3 has a number of teeth 8, the teeth 8 are along the The upper surface of the inverted cone of the tapered rod 4 and the edge of the washer 3 are connected to form a straight convex strip 15 extending outward; the convex strip 15 can also be designed in an arc shape. The fixing screws for installation proposed by Guangdong Yueluo Hardware Industry Co., Ltd. can be made of metal materials in one piece. As shown in Figure 3, it is a schematic diagram of the installation of Guangdong Yueluo Hardware Industry Co., Ltd. for PCB board fixing. When installing, first pass the screw body 1 of the fixing screw through the mounting hole 10 and the copper column 11 provided on the PCB board 9, so that the tail 7 of the screw reaches the mounting hole 13 on the casing 12, and then use the tightening tool 14 to insert the screw At the notch on the top of the head, forcefully press the inverted cone design taper rod 4 of the screw body 1 into the mounting hole 10, so that the tail 7 passes through the mounting hole 13. Due to the outer diameter D at the bottom of the taper rod and the screw mounting hole The aperture size of 10 is equal, and the fixing screws are pressed and fixed, so that the PCB board 9 can be automatically corrected in the process of fixing its front, back, left and right deflections, and the accuracy of the installation position of the PCB board 9 can be ensured. As shown in Figure 4, after the fixing screw is screwed into the casing, the washer 3 is fully contacted and pressed on the PCB board 9, and the PCB board 9, the copper column 11 and the casing 12 are firmly connected together without sliding. . The teeth 8 on the washer 3 are in full contact with the surface of the PCB board 9, so that a ground wire path is set up between the PCB board 9 and the casing 13 by the metal fixing screw 1, thereby ensuring that the PCB board 9 is fully grounded , the design of the teeth 12 on the washer 3 also has a non-slip function. The fixing screws for installation designed by Guangdong Yueluo Hardware Industry Co., Ltd. make use of the cooperation, friction and electrical conductivity in the mechanical connection, which fully guarantees the firm installation of the PCB board and the chassis and the good grounding of the PCB board. Moreover, the ellipsoid tail of the fixing screw The surface is relatively smooth, even if the mounting holes are exposed, it will not cause scratches on the hands and desktop. The above is only the embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., and does not limit the scope of Guangdong Yueluo Hardware Industry Co., Ltd., any equivalent structure made by using the contents of the description and drawings of Guangdong Yueluo Hardware Industry Co., Ltd. or etc. Effective process transformation, or direct or indirect application in other related technical fields, are also included in the protection scope of Guangdong Yueluo Hardware Industry Co., Ltd.
Standard parts are commonly used parts, which are widely used in various mechanical structures. Among them, the T-track bolt is a common standard part. The existing T-shaped track bolts, especially those used in high-speed railways, are often installed in pre-buried tracks, and the T-shaped track bolts are not easy to install, which may easily cause positional deviation.
The technical scheme adopted by Guangdong Yueluo Hardware Industry Co., Ltd. is: a pin pressure riveting structure, including a pin, a cavity and a pressure riveting fixture, the pin is a columnar structure, an annular groove is arranged on the surface of the pin, and the cavity is The body is provided with a light hole, the depth of the light hole is greater than the height of the annular groove relative to the bottom of the pin, the lower end of the pin is inserted into the light hole, the pressure riveting fixture includes a pressure riveting part and a pressure-bearing part located on the top of the pressure riveting part, so The riveting part and the pressure-bearing part are provided with coaxial and penetrating connecting holes, and the upper ends of the pins are sleeved in the connecting holes.
When using a rivet nut, drill a hole corresponding to the outer diameter of the rivet nut on the thin wall, then place the rivet nut on the bolt of the special rivet gun, push the handle to screw in the rivet nut, and put it into the drilled hole. In the workpiece, squeeze the handle, the rivet nut expands, and the deformed skirt bulges and deforms. At this time, the workpiece is tightened. After riveting, the handle is pulled out, the bolt is released from the rivet nut, and the corresponding screw is screwed into the rivet nut threaded hole. , forming a tight riveted body.
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