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 18 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.
The existing automobile fastener nut is a common nut. After the nut is matched with the bolt, during the tightening or disassembly process, there will be a phenomenon of sliding wire, and the safety factor is relatively low; It is difficult to guarantee, easy to rust, requires frequent inspection and replacement, and increases the cost of using the car, which can no longer meet the needs of the market.
Usually, a tight fit is used between the cylindrical pin and the pin hole, such as the cooperation between the cylindrical pin and the pin hole on the rotating shaft of the motor. Due to the tight fitting structure between the cylindrical pin and the pin hole, the shaft with the pin hole needs to be well positioned during assembly, and then the cylindrical pin is aligned with the pin hole, and then knocked or pressed to fit. The cylindrical pin is pressed into the pin hole. There is no device specially used for the installation of cylindrical pins in the prior art, and two or more people are required to cooperate to install the cylindrical pins into the pin holes. installation quality.
In the process of electronic accessories such as mobile phones and computers, especially multi-layer circuit boards, there are generally fixed connections between multi-layer circuit boards or other components. At present, there are two main connection methods. One is to use laser welding. However, the laser welding equipment is expensive and has very high requirements on the position of the weldment. Therefore, during welding, it must be ensured that the final position of the weldment needs to be the same as the laser beam will impact. Solder joint alignment. The other is to use a metal rivet to pass through the positioning hole, and then impact the rivet with a punching needle, so that the open end of the rivet is deformed and opened and pressed on the fixed piece to form a rivet fixed state. However, in actual operation, when the open end of the rivet tube is opened and deformed by the impact, strong cracking often occurs, resulting in a small amount of conductive fracture debris, which falls on the circuit board or other devices to be connected, causing Short circuit, in view of this shortcoming, some manufacturers have changed the metal rivets to plastic materials, but the plastic rivets have poor ductility and often break when impacted with a punching needle, resulting in the failure to achieve the riveting fixing force of the original metal rivets. In addition, the above two fixing methods are complicated in operation and low in installation efficiency.
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