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 14 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.
Figure 1 is a schematic structural diagram of Guangdong Yueluo Hardware Industry Co., Ltd. Figure 2 is a front view of the structure of the riveted positioning block. FIG. 3 is a top view of the structure of the riveted positioning block. Figure 4 is a front view of the structure of the riveting lower die. Figure 5 is a side view of the structure of the riveting lower die. 1, I is a rivet, 2 is a riveting positioning block, 3 is a product, 4 is another product, and 5 is a riveting lower die. [0017] Referring to Figure 2, Figure 3, 2-1 is a positioning pin, 2-2 is a rivet hole, and 2-3 is a through hole. Referring to Figure 4, Figure 5, 5-1 is a positioning hole, 5-2 is a guide block, 5_3 is a countersunk screw hole, and 5_4 is a vacant hole.
Washers are accessories used between the nut and the connecting piece to disperse the pressure of the nut on the connected piece, thereby protecting the connected piece. The general gasket is a flat gasket, which is easy to loosen after long-term use, and the stability is not high. There are also some elastic washers, which have poor elastic stability and short service life.
Basic requirements for the installation of T-bolt sleeve components: only when the T-head and the middle slot of the anchoring plate are in good agreement and the anchoring surfaces are in close contact, can the force be evenly applied. If the T-head and the anchoring plate are in line contact, even only point contact , the bolt is partially stressed, which will seriously affect the life. Therefore, the verticality of the sleeve installation must be less than or equal to 1/1000, that is, the horizontality of the anchoring plate surface must be less than or equal to 1/1000, and the center deviation of the sleeve must be controlled within 5mm (the center deviation of the T-bolt is 2mm). Therefore, improving the embedded accuracy of the T-bolt sleeve is the key to the installation of the T-bolt integral sleeve.
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