What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In the process of driving the car, it is inevitable to use the brake frequently, which will cause the gap between the brake drum and the friction pad of the car to become larger. Therefore, it needs to be adjusted in time, otherwise, the hidden danger of unsafe driving will be buried due to the excessive braking distance and the out-of-round brake drum. Therefore, motor vehicles must be equipped with automatic adjustment arms. In the existing automatic adjustment arm, the worm inside the housing is limited by the spring pad, the spring and the spring cover, and the end face of the spring pad is directly in contact with the worm, and the rotation of the worm is inflexible due to frictional resistance during rotation.
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.
At present, with the development of my country's railway industry, many railway fastener systems involve T-bolts. The structure is shown in Figure 1. The dimensions that need to be inspected are head width A, head length B, and head straight table height. C. The height of the head slope D, the total length of the bolt E, and the major diameter of the bolt F. Due to the irregular shape of these places to be inspected, the measurement is difficult. The measurement of general measuring tools is not only slow, but also difficult to control human errors, resulting in some extreme upper limits and There are disputes and misjudgments about the size of the extreme lower limit when judging qualified and unqualified.
In the existing production technology, such as construction machinery, double nuts are often used to fasten the workpiece. With the long-term vibration in the working environment, there is a thread gap between the nut and the bolt, and there is no self-assembly between the nut and the bolt. Locking action, the relative displacement between the nut and the bolt will occur under the action of vibration, resulting in the loosening of the nut and the bolt and the loss of the tightening effect.
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