What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Mine trucks are required for underground construction and coal transportation. With the vigorous development of energy, the output of coal has increased significantly, and the demand for mine trucks has increased. The axle card is an important part of the mine car. Its shape is irregular, and the blank is a casting. It needs to be finished on the semicircular surface whose upper center is matched with the mine car axle. At present, the mine truck axle card is generally processed by a milling machine, which has the problem of low efficiency.
flat washer is also called a flat washer. It is mainly stamped out of an iron plate. The shape is generally a flat washer with a hole in the middle. The size of this hole is generally determined according to customer requirements. There are 9 standards for flat washers in my country. From 2000 to 2002, GB/T97.3-2000, GB/T5286-2001, GB/T95-2002, GB/T96.1-2002, GB/T96.2 were approved and released respectively. -2002, GB/T97.1-2002, GB/T97.2-2002, GB/T97.4-2002 and GB/T5287-2002 Standard for flat washers. According to the performance grade of the flat washer, the author recommends the use of materials: ST12, ST13, Q235, Q215, Q195, etc. can be selected for the 100HV grade, and the surface hardness can reach about 110HV; 08F, 08Al, 10, 10F, etc. can be selected for the 140HV grade etc., the surface hardness can reach about 140HV; for 200HV and 300HV grades, 45, 50, 60, 70 or 65Mn steel should be selected, which can be quenched and tempered by heat treatment to meet the technical requirements of 200~300HV and 300~400HV. Because according to the standard, flat washers of 100HV and 140HV grades can be manufactured from mild steel. Most enterprises use Baosteel materials when selecting materials, which is convenient for cold stamping. The following is a brief description of Baosteel's standards. Compared with the BZJ407-1999 standard, there are major changes in Continuous Cold Rolled Low-Carbon Steel Plates and Strips and the enterprise standard: (1) The grades have been revised and integrated, and the grades have been changed from 8 commonly used to 5. St12 is changed to DC01; ST13 is changed to DC03; St14, St15 is changed to DC04; BSC2 is changed to DC05; St16, St14-T, BSC3 is changed to DC06. (2) The surface quality level is changed from two to three: the higher-level finishing surface (FB), the surface is allowed to have a small amount of defects that do not affect the formability and coating and plating adhesion, such as slight scratches, indentations, Pock, roll printing and oxidation color, etc. Premium Finished Surface (FC) products have no visible defects on the better of the two sides and must meet at least FB requirements on the other side. The super-advanced finishing (FD) product must not have any defects on the better side of the two sides, that is, it cannot affect the appearance quality after painting or the appearance quality after electroplating, and the other side must at least meet the requirements of FB. (3) The surface structure is modified from four to two, and the control value of surface roughness is increased. The average roughness Ra when the surface structure is pitted (D) is 0.6 μm. (4) The provisions on Si and residual elements in the chemical composition of the five grades have been cancelled, and the contents of elements such as C, S, and Alt have been revised.
At present, with the continuous growth of the demand for communication products, higher and higher requirements are put forward for the production capacity of equipment manufacturers, and at the same time, the requirements for the cost, weight and reliability of communication products are also more and more stringent. In order to facilitate the positioning of the equipment, pins are often used to complete the equipment, and a certain cost is incurred for its manufacture and assembly. In the past, such parts have been assembled in the form of threads. In order to ensure that the assembly height is within the specified range and to prevent loosening, bar turning is often used to form threads and positioning steps, and thread pinning glue is used in the assembly, and the cost of machining is relatively high. Large, more material waste. Based on the above drawbacks, in order to better solve this problem, some existing manufacturers use the interference fit riveting method, which solves the problem of material waste and anti-loosening, but the inner diameter of the pin hole and the outer diameter of the pin are matched. The machining accuracy of the machine is relatively high. Once the matching size is out of tolerance, a second matching is required, which wastes working hours and increases the slack time.
T-slot convenient bolt that can be used for the middle port of the T-slot and directly realizes the assembly and tightening of the bolt and the nut. Technical Background At present, the bolts for T-slots are assembled from two side ports of the T-slots. When the length of the T-slot is long, it is time-consuming and laborious to install from the side port to the center port at the designated position. In addition, the two side ports of the T-slot are often blocked by other components, and the bolts for the T-slot cannot be installed or removed without disassembling other components. The utility model makes some improvements to the prior art. SUMMARY OF THE INVENTION The purpose of the present invention is to provide a T-slot convenient bolt with simple structure and convenient mounting and dismounting for the current situation that the existing T-slot bolts are inconvenient to install and disassemble.
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