Medium No.: TH131.3: A 1 Introduction The basic function of fasteners is to connect and transfer loads. Threaded fasteners have the greatest advantage over other fasteners in that they are easier to disassemble and are therefore the most widely used. Its biggest disadvantage is that it is easy to loose under the action of impact, vibration or variable load, so the problem of vibration loosening has always been the biggest problem of threaded fasteners. Threaded fasteners are small and can cause serious accidents if they fail. This is not uncommon in engineering. Especially in recent years, with the rapid development of a series of emerging technologies, the service conditions of threaded fasteners are sometimes extremely harsh and complicated, and there is a slight negligence in design, processing and use, which may fail. Therefore, the life of the fastener is directly related to the safe operation and use/thread angle of the whole equipment; the friction coefficient of the thread pair; the friction coefficient of the bearing surface; the equivalent diameter of the frictional moment of the core nut bearing surface. 2 reasons for the looseness of the thread The tightening torque of the threaded joint If the loose torque is theoretically analyzed, as long as the ratio of the loose torque to the tightening torque is not more than 0.8, the threaded joint will not loosen. However, under the action of impact, vibration, variable load or in a high temperature environment, the pre-tightening force of the threaded joint is greatly reduced, the tightening torque is reduced, and finally the thread loosening failure occurs. There is also corrosion or corrosion of the thread surface, so that the geometry of the thread surface is destroyed; there is much oil infiltration, which can effectively prevent the rotation of the shaft. 2 square plates (180mmx170mmx20mm), the center of the square plate is machined into a square hole with a side length of 42mm, which is matched with the tail end of the tail, and 4 angle drills are 4 screw holes like 8mm. Attack two M16 wire holes on both sides of the tailstock, which is symmetrical with the original hole of the stitching card. Install the tail drum into the U-shaped groove, put the two square plates on the two ends of the shaft, and connect the two square plates to the outside of the two side plates of the tailstock with 8 M16 screws, so that the tail of the trap is ready. 5 characteristics of the tail of the tail machine The shaft seat of the tail drum is no longer directly on both sides of the tailstock, so that the shaft and the two side plates do not wear each other. The square plate can effectively prevent the tail shaft from rotating. The wearing parts are square plates, which are easy to replace, just remove the screws, which greatly improves the service life of the tailstock. -), Jiangsu Xiangyang, assistant engineer.丨 Graduated from Xuzhou Coal Construction Engineering School in 992, majoring in mechanical and electrical engineering. Tel: 056丨-4905012. Between the threaded contact surfaces, the friction coefficient is reduced; the threaded joint generates creep and relaxation under the action of long-term alternating load. All of the above reasons will loosen the threaded connection. 3 Traditional threaded locking method The traditional threaded locking method can be summarized into three categories according to its principle: (1) Friction and anti-loose This is the most widely used anti-loose method. This can be achieved by axially or simultaneously pressing the thread pair in both directions. Such as elastic washers, double nuts, self-locking nuts and nylon insert lock nuts. U) Mechanical anti-loose is the use of a stop to directly limit the relative rotation of the thread pair. Such as the use of cotter pins, tandem wire and stop washers. (3) After the tightening, the rivet punching and anti-loose adopts the method of punching, welding, bonding, etc., so that the thread pair loses the motion pair characteristics and is connected to be undetachable. Reaming bolts are also a common method. When the reaming bolts are connected, the bolt holes are tightly fitted with the bolt shank. The main cause of the bolt loosening is the radial vibration along the bolt, and the vibration along the axial direction of the bolt has a much smaller effect on the looseness of the bolt. 4 Several new threaded joint technology practices have shown that the above measures have insurmountable shortcomings. If you need to add a lock, process or material with a specific function, and its locking function is only effective once, it can not be reused, especially in the temperature or low temperature environment. Therefore, to a certain extent, the problem of the looseness of the threaded fastener has not been satisfactorily solved for a long time. In recent years, with the rapid development of science and technology, many new types of threaded anti-loosening methods have emerged. A schematic diagram of the fixed torque bolt structure is shown. <7 bolt stress; E-bolt material elastic modulus; 4 thread nominal stress cross-sectional area. Therefore, the reserved gap between the stress rod and the end cap can be obtained from the product of the effective length of the bolt and the strain. It can be seen that such a fixed torque bolt is easy to operate, but its function is extremely important. The screw-resistant screw is the first product developed by Nylok in the world. It is a special technology to permanently adhere special engineering resin materials to the screw. Using the resilience of engineering resin material, the bolt and nut are locked. In the process of pressing, the resin material is extruded to generate strong friction force, and the absolute resistance to vibration and impact is achieved, and the problem of looseness of the screw is completely solved. After the threaded portion of the screw is processed, the full thread contact is generated, so that there is no longer any spin or slack. In places where the number of repeated uses is higher, the more effective the anti-loose effect is. Although the cost is relatively low, such screws should be used at the more important joints. It should not be used under high temperature, low temperature and chemical corrosion conditions. The Spencer thread is a unique design that is preloaded with a locking internal thread. It has an anomalous ability to resist lateral vibration, which is the main cause of loose threads. Spiro's thread shape has a unique 30 wedge-shaped bevel on its root (see Part 1), which is made with a special Spire tool. When the shimming nut is assembled, the crest of the external thread is tightly placed against the wedge-shaped bevel of the sturdy thread 30, thus preventing lateral movement of any thread relative to the female thread. When the nut is tightened on the bolt or the bolt is screwed into the nut, the crest of the male thread tightly wedges the 30. cone surface of the female thread root, thereby generating a large locking force and is a full thread lock. Tight. The Tang's thread is composed of two kinds of spirals, left-handed and right-handed, on the same thread segment. It has both the characteristics of left-handed thread and right-handed thread. It can be combined with left-handed thread and right-handed screw. The application of adhesive coating on the pulverizer fan mill should be put into the sky 2, Jia Liangju 1 (1. China University of Mining and Technology, Xuzhou, Jiangsu 22008; 2. Zhejiang University, Hangzhou 310027, Zhejiang) ceramic powder, forming different coating. Through the test of ML-100 abrasive wear tester, it is found that the wear resistance of epoxy resin coating is closely related to the particle size and content of ceramic powder. The addition amount of the curing agent polyamide also affects the wear resistance of the coating, and the wear-resistant coating of the optimized design is compared with the 45 steel, and the wear resistance is more than 5 times that of the 45 steel. Medium No.: TQ323.5: A 1 Introduction Epoxy adhesive coatings have excellent wear resistance and are widely used in material protection and parts repair, such as: scratching of parts, casting defects, external cracks, part wear, Leakage of parts, etc. Because the repair work is simple, efficient, and economically viable, the process has received increasing attention. At present, there are a lot of wear-resistant and wear-repairing patterns at home and abroad (see). Tang's crepe structure. Locking the female (left-handed) 2. Tightening nut (right-handed) The Down's thread can solve the problem of loosening by using the characteristics of the thread itself. When connecting, use two nuts with different directions of rotation; the nut on the workpiece support surface is called the fastening nut, the nut on the non-bearing surface is called the lock nut, the fastening nut and the lock nut are two different rotations. To the nut, pre-tighten the tightening nut before use, and then pre-tighten the lock nut. In the case of vibration and shock, the tightening nut tends to loosen. However, since the loosening direction of the tightening nut is the tightening direction of the lock nut, the tightening of the lock nut just prevents the fastening rubber from being listed, such as the domestic TG-205, TG-301, TG-406, TG-518, SK63 and other famous foreign brands include Devcon Titanium Alloy Repair Agent, McCarty Adhesive, Belzona Ceramic EC and Metal K Repair Agent. In this study, epoxy resin and ceramic powder were used to prepare a wear-resistant grain wear coating for the anti-wear of the pulverizer fan mill. After industrial test, the life of the fan mill was obviously improved. The loosening of the nut causes the fastening nut to not come loose. 5 Conclusions The parts of mining machinery are generally threaded, and most of them are under heavy load, vibration and alternating load conditions. Therefore, it should be combined with the specific machinery and its use conditions, select the standard parts of the corresponding method, or design and manufacture by the corresponding principle to ensure the reliability of the threaded connection. Professional Magnetic Assembly Manufacturer in China. Specialize In Manufacturing Magnetic Window Cleaner, Magnetic Name Badge, Magnetic Sweeper, etc products. Magnetic Assembly Magnetic Window Cleaner,,Magnetic Name Badge,Magnetic Sweeper ,Magnetic Cleaner Ningbo Besten Magnet Co., Ltd. , https://www.bestenmagnets.com