What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The material of the second combination screw: It is decided to use the test machine to test the material of the combination screw wire, which is divided into iron and stainless steel. Iron wire is divided into 1010 wire and 1018 wire, 10B21 wire, etc., stainless steel is divided into stainless steel 201, stainless steel 304, stainless steel 316 and so on. The provisions of the national label of three combination screws: Generally, those who have experience in combination screws can be separated by using the inner eye. The difference between hexagon heads. Use a caliper to measure out the three-combination screw specifications. How big is it, how long is it, how thick is the head of the combination screw, how thick is the flat washer, and what is the outer diameter of the flat washer. How many hours is the salt spray of the combination screw measured with a salt spray machine. Use the environmental test machine to test whether the three-combination screw is environmentally friendly. Still not environmentally friendly.
The types of rivets can be roughly divided into open type, closed type, double drum type and single drum type series. The following is a brief description of their respective models. Countersunk head blind rivets: For the riveting of riveting parts that require smooth and beautiful surfaces after riveting. Double-drum blind rivet: During riveting, the mandrel pulls the end of the rivet body into a double-drum shape, clamps the two structural parts to be riveted, and can reduce the pressure acting on the surface of the structural parts. Uses: Mainly used for riveting various thin structural parts in various vehicles, ships, construction, machinery, electronics and other industries. Blind rivet with large brim: Compared with ordinary blind rivets, the diameter of the aluminum cap of this rivet is significantly larger. When the rivet is riveted with the connector, it has a larger contact area and a stronger supporting surface, which can enhance the torque Strength, can withstand higher radial tension. Applicable industry: It is suitable for fastening soft and fragile surface materials and extra-large holes. The increased diameter of the brim has special protection applications for soft materials. Closed Blind Rivet: Designed to wrap around the mandrel head after riveting, ideal for many applications where waterproofing is required. With high shear force, anti-vibration, anti-high pressure.
The main technical problem solved by Guangdong Yueluo Hardware Industry Co., Ltd. is to provide a fixing screw for installation, so as to provide a PCB fixing method with convenient operation, reliable connection and low production cost. In order to solve the above-mentioned technical problems, a technical solution adopted by Guangdong Yueluo Hardware Industry Co., Ltd. is to provide a fixing screw for installation, which includes a screw body, the axial surface of the screw body is formed with extended screw teeth, and the screw body is The bottom has a hemispherical screw tail, the top of the screw body is provided with a screw head, and the upper surface of the screw head is provided with a slot. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the screw body is composed of an upper tapered rod and a lower cylindrical screw rod, and the tapered rod is an inverted cone. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the diameter of the circular upper surface of the inverted cone of the taper rod is equal to the diameter of the screw mounting hole. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the screw further has a washer, the washer is arranged between the screw head and the screw body, and the washer is a cylinder. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the lower surface of the cylindrical washer has a plurality of teeth, and the teeth are along the edge of the connection between the upper surface of the inverted cone of the tapered rod and the washer Ribs formed by extending outwards. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the teeth of the washer are in contact with and pressed against the PCB board. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the protruding strip is an arc-shaped or straight-shaped structure. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the notch opened on the upper surface of the screw head is a slot. [0018] According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the notch provided on the upper surface of the screw head is a cross groove. According to a preferred embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., the fixing screw is integrally formed with conductive material. Compared with the existing technology, the fixing screws for installation designed by Guangdong Yueluo Hardware Industry Co., Ltd. can not only ensure the accuracy of the PCB installation position, but also can be installed easily and reliably, which greatly reduces the manufacturing cost and waste of metal materials.
The front wall sound insulation pad is used to absorb the heat and noise transmitted by the firewall, and also plays the role of heat insulation and vibration isolation, ensuring a relatively quiet and comfortable environment in the car and improving ride comfort. As shown in FIGS. 1 and 2 , the front wall sound insulation and heat insulation pad 101 is generally fixed to the vehicle body by means of screw buckles 102 . The screws 100 are clamped by the clamping feet 103 in the screw The limiting rib 104 clamps the screw 100. After the screw 100 is clamped into the screw buckle 102, the tail end of the screw 100 is exposed, which is easy to scratch the operator when assembling other components, and the exposed screw 100 is easy to cause corrosion, thereby affecting the connection strength of the screw 100, and also The service life of the screw 107 is reduced.
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