What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
With the rapid development of China's machinery industry, especially the development of heavy industry, the demand for large-scale metal processing equipment is increasing; at the same time, higher requirements are also placed on the technical parameters of the equipment. For some large-scale CNC equipment, to ensure the machining accuracy of the whole product, it is not only necessary to rely on high-performance components such as full closed-loop control and precision transmission components, but also requires the positioning and stability of the joint surfaces between the large and medium-sized components of the equipment. The common positioning of the joint surface between large components adopts flat key positioning, and this method requires processing the keyway at the joint surface of the large components. Since the joint surface of large parts is affected by factors such as processing and splicing, it cannot guarantee that the keyways on the large parts combined can be matched according to the theoretical requirements. Therefore, the positioning flat key needs to press the flat key in the two parts of large parts. Different repair allowances Trim into a stepped shape. The height difference of this keyway in different large components makes a single flat key need to be repaired on four sides, which increases the difficulty of the key repair process and makes it difficult to improve work efficiency. Not only that, when the flat key is repaired and assembled, it must be in an interference fit with the keyway, which makes the disassembly and assembly of the flat key more laborious.
At present, the commonly used shaft retaining rings in the market usually include elastic retaining rings and screw locking retaining rings, but they all require tools to be installed and disassembled, which is relatively inconvenient to use.
The bolt performance grade label consists of two parts of numbers, which represent the nominal tensile strength value and yield ratio of the bolt material respectively. For example: a bolt with a performance level of 4.6, its meaning is: 1. The nominal tensile strength of the bolt material is 400MPa; 2. The yield ratio of the bolt material is 0.6; 3. The nominal yield strength of the bolt material is 400×0.6=240MPa Grade 10.9 high-strength bolts, after heat treatment, can reach: 1. The nominal tensile strength of the bolt material reaches 1000MPa; 2. The yield ratio of the bolt material is 0.9; 3. The nominal yield strength of the bolt material reaches 1000×0.9=900MPa class
Traditionally used for plastic fastening screws, most of the thread designs are self-tapping threads, but for different plastic types, the self-tapping threads also have many different classifications, such as PT profile, Plastite series, Remform profile, etc. The structural parameters and manufacturing process of these threads are inconsistent, or require different main molds and wires. Therefore, to find a plastic screw that is universally applicable to various plastic types, has a single pressing structure, low-cost and simple manufacturing process, especially its special self-tapping thread, is an important issue that needs to be solved urgently at present. question. The purpose of Yueluo Yueluo Guangdong Yueluo Hardware Industry Co., Ltd. is to propose a plastic screw to solve the screw fastening problem that is generally applicable to different plastics. The purpose of Yueluo Guangdong Yueluo Hardware Industry Co., Ltd. is to realize a kind of plastic screw through the following technical scheme, it is characterized in that, the thread of the screw is composed of asymmetric threads with a profile angle of 30°, and the threads are The bottom surface of the connection between them is an arc surface. Yueluo preferably, the asymmetrical thread has a forward thread angle greater than the reverse thread angle, and the sum of the two-direction thread angles is 30°. Yueluo further preferred that the tooth profile angle of the asymmetrical screw thread in the forward mounting direction is 20 degrees, and the tooth profile angle in the reverse mounting direction is 14 degrees. Yueluo Guangdong Yueluo Hardware Industry Co., Ltd.'s application of plastic screws, through the improvement of special thread structure, reduces the radial pressure and installation torque when the screw is installed, reduces the damage to the plastic hole; and increases the pull-out resistance of the screw force, it is not easy to appear loose assembly. At the same time, the design of the bottom surface of the connection between the threads of the arc optimizes the flow of the material of the installation object, which improves the integrity of the installation connection.
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