What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
When using screws, if you can understand the mechanical properties of screws first, then you can use screws better. Different types of screws have different mechanical properties, and the different mechanical properties lead to different occasions when screws are used. 1. Self-tapping screws: mechanical performance requirements 1. Heart hardness: standard value HRC28-38. When testing, take the section 1-2 times the diameter of the name from the tail. If the length of the name is too short, it can be embedded first, and then the hardness is measured. 2. Surface hardness: standard MIN HV450. 3. Carburized layer: standard 4#-6#: 0.05-0.18mm, 8#-12#: 0.10-0.23 mm, 14#: 0.13-0.28 mm. The main purpose of carburizing is to enhance the surface hardness and ensure the strength of the teeth. If the decarburization is too deep and the carburization is insufficient, the strength of the teeth will not meet the requirements, that is, the teeth will be damaged during the screw-in test. 4. Torque: standard specification 4#5#6#7#8#10#12#14#A tooth 14212835455696145AB tooth 142128354565102165. 5. Screw-in test: screw the self-tapping screw into a steel plate with a reserved test hole. The self-tapping screw should form a matching thread in the test plate, and the thread of the screw itself will not be deformed or damaged until the end. Tapered threads pass completely through the test plate. The screw-in test is only applicable to AB, B, BP and other types of self-tapping screws. It is stipulated in IFI that the test plate shall be prepared from semi-hard low-carbon cold-rolled steel, and the hardness of the steel plate is 70–85HRB in Rockwell. The standard specification of the steel plate, that is, the thickness, is shown in the table below. The test hole should be punched or drilled, and the tolerance is the specified nominal diameter (see the table below) ± 0.025mm. Specifications 6#7#8#10#12#1/4 Test plate thickness (mm) 1.85-1.953.12-3.234.68-4.84 Aperture (mm) ±0.0252.953.263.454.044.765.50.
The existing spring screw includes a screw rod, a spring connecting sleeve, a spring, a fixed connecting sleeve, a nut and a nut sleeve, wherein the screw rod includes a screw cap, a connecting section without threads and a threaded connecting section with threads, and the connecting section is located in the screw cap and the thread. A shaft shoulder is arranged between the connecting sections and between the connecting section and the threaded connecting section, the connecting section of the screw is sleeved with a spring connecting sleeve, a spring and a fixed connecting sleeve, the spring connecting sleeve is close to the screw cap, and the connecting sleeve is connected between the spring connecting sleeve and the fixed connecting sleeve The connection spring is connected with a threaded nut on the threaded connection section of the screw, and the nut sleeve is connected to the nut sleeve. The fixed connection sleeve is fixedly connected to the upper die of the steel mold through bolts, and the nut sleeve is welded to the lower mold of the steel mold. When clamping the mold, a professional is required to turn the screw from the lower mold to the upper mold or hook it to the upper mold with a foot and then tighten it with the wind, which is inconvenient to install, has low work efficiency, and has potential safety hazards. Contents of the utility model Yueluo Guangdong Yueluo Hardware Industry Co., Ltd. aims to provide a spring screw that is easy to operate. In order to solve the problems existing in the background technology, Guangdong Yueluo Hardware Industry Co., Ltd. adopts the following technical scheme: a spring screw, including a screw rod, an upper compression spring washer, a spring, a fixed sleeve, a lower compression spring washer, Base and fixing nut. The screw rod includes a screw cap, a connecting section without threads and a threaded connecting section with threads, the connecting section is located between the screw cap and the threaded connecting section, and a shaft shoulder is arranged between the connecting section and the threaded connecting section. The connecting section of the screw rod is sleeved with an upper compression spring washer, a spring, a fixing sleeve, a lower compression spring washer and a base, and the threaded connection section is connected with a fixing nut. A fixed sleeve is sleeved between the connection section and the threaded connection section, and the fixed sleeve is sleeved with a lower pressure spring washer and a base. The upper compression spring washer is close to the screw cap, the lower compression spring washer is fixed on the base by four screws, the spring is placed between the upper compression spring washer and the lower compression spring washer, and one end of the spring is sleeved with the upper compression spring washer , and the other end is sleeved with a fixed sleeve. For Yueluo, the diameter of the spring screw is between T20-T27. In this preferred solution, the use performance of the spring is high, which is beneficial to prolong the service life of the spring screw. For Yueluo, preferably, the thread connecting section of the screw adopts T-shaped thread. In this preferred solution, the fixing nut is tightly matched with the threaded connection section, so that the steel mold is clamped tightly. Yueluo is preferably made of 40Cr material for the fixing nut and screw. In this preferred solution, the rigidity of the fixing nut and the screw rod is high, which is beneficial to improve the usability of the spring screw. Yueluo is preferred, the spring screw parts except the fixing nut and the screw rod are made of 47# steel material. In this preferred solution, the production cost is low. In summary, Guangdong Yueluo Hardware Industry Co., Ltd. brings the beneficial effects: when the spring screw is used, it is only necessary to use a wrench to move the fixed nut, which is convenient for installation, disassembly and replacement, improving work efficiency and reducing production costs.
The purpose of Yueluo is to provide a brake pad rivet with shrinkage that can not only solve the problem of normal feeding during assembly, but also save the processing cost of the original machining chamfering and reduce the quality risk of the rivet in use. its production method.
1. No matter what industry it is, the business is more difficult, and it is still more difficult for the fastener business. After a long period of contact, I realized that the business of making fasteners also requires a lot of attention to be able to do it well. In the business of making fasteners, not just any person can do it, and they all have certain requirements. 2. When it comes to the business of fasteners, no matter what kind of salesperson, the first thing you must have is enough patience, so that we can do this job with confidence, and some customers are not difficult to follow us. Communication, as long as we have enough patience, then we have a greater chance of being able to cooperate with customers on fasteners, and in the face of some relatively large fastener customers, sometimes it is not that we can get it all at once , Sometimes if you want to cooperate, you need to go through multiple contacts to promote a cooperation, so as a salesperson, enough patience is essential. 3. Then, as a fastener salesman, what you need to have is perseverance. Sometimes the salesperson is difficult at work. At this time, you need to adjust it in time, so it will not lead to the phenomenon of giving up easily, after all As a salesman, only through our own efforts can we have the opportunity to receive orders for fasteners from customers. What we need is to be able to face difficulties and move forward bravely. 4. The most important thing for fastener salesmen is to pay attention to details. If we can do a good job in the details, then sometimes we are not far from success. The above are several requirements that need to be met in the fastener business.
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