Key technologies for anti-loosening design of threaded built-in zero positioner

In the modern industrial field, threaded connection is a widely used mechanical connection method, and its reliability directly affects the operating safety and performance of the equipment. As a key component for accurately controlling the position and state of threaded connection, the threaded built-in zero positioner plays an important role in various high-end manufacturing scenarios such as precision machinery, automation equipment, and aerospace. The anti-loosening design of the zero positioner is the core to ensure the stable realization of its function, which is related to the stability and reliability of the entire system.
1. Mechanical structure design technology
(I) Special thread structure design
The anti-loosening basis of the threaded built-in zero positioner lies in the structural design of the thread itself. The special thread tooth shape is one of the important anti-loosening means. For example, the asymmetric tooth shape design makes the force direction of the thread more inclined to maintain the tightened state during the screwing process. When subjected to vibration or external force, this asymmetric structure can generate additional friction to prevent the thread from loosening. In addition, increasing the number of threads and reducing the pitch can also effectively improve the anti-loosening performance of the threaded connection. More teeth and smaller pitch means more thread contact points per unit length. Under the same axial force, each contact point bears less force, thus reducing the risk of thread loosening.
(II) Elastic element auxiliary structure
Setting elastic elements inside the zero positioner is an effective way to enhance the anti-loosening ability. Common elastic elements include spring washers, wave washers, etc. When tightening the nut, the spring washer will be subjected to axial pressure and produce elastic deformation. Its rebound force can always maintain a certain axial tension between the thread pairs, thereby increasing the friction between the threads and preventing loosening. The wave washer, through its special wave shape, produces multi-directional elastic deformation when subjected to force, which can not only provide axial preload, but also absorb vibration energy to a certain extent, reducing the impact of vibration on threaded connections. In addition, disc springs can also be used. It has the characteristics of high stiffness and strong buffering and vibration absorption ability. It can provide a large axial force in a small space and effectively prevent the zero positioner from loosening under complex working conditions.
(III) Mechanical locking structure
The mechanical locking structure is a reliable anti-loosening method. Common mechanical locking structures include cotter pins, stop washers, and wire locks. Cotter pins are usually used in conjunction with slotted nuts. The cotter pins are inserted into the slots of the nut and the pin holes of the bolts, and then the tail of the cotter pin is broken apart to prevent the nut from rotating relative to the bolt, thereby preventing loosening. The stop washers, through their special shape and installation method, fix the nut or bolt with the connected parts to limit the relative movement between them. The wire lock is to connect multiple bolts or nuts in series with steel wire. When one of the bolts or nuts tends to loosen, it will be constrained by the steel wire, thereby achieving the purpose of overall loosening prevention. These mechanical locking structures are simple and reliable, and are suitable for occasions with high anti-loosening requirements.
2. Material selection and processing technology
(I) Application of high-strength materials
The selection of high-strength materials is the basis for improving the anti-loosening performance of the zero positioner. High-strength materials have high tensile strength and yield strength, can withstand greater axial force and external force, and reduce thread loosening caused by material deformation. For example, in the field of aerospace, titanium alloy, high-strength alloy steel and other materials are often used to make threaded built-in zero positioners. These materials are not only high in strength, but also have good corrosion resistance and fatigue resistance, and can work stably for a long time under harsh environmental conditions. In addition, for some special working conditions, composite materials can also be used, which have the advantages of light weight, high strength, and corrosion resistance. While reducing the weight of the equipment, it can ensure the anti-loosening performance of the zero positioner.
(II) Surface treatment technology
Surface treatment technology can effectively improve the surface performance of the zero positioner and enhance its anti-loosening ability. Common surface treatment methods include metal plating treatments such as galvanizing, cadmium plating, and nickel plating, as well as chemical treatments such as blackening and phosphating. Metal plating treatment can not only improve the corrosion resistance of the zero positioner, but also change the friction coefficient of the surface to a certain extent. For example, the galvanized layer can increase the surface roughness, thereby increasing the friction between the threads and preventing loosening. Chemical treatment improves its wear resistance and corrosion resistance by forming a dense protective film on the surface of the zero positioner. In addition, surface hardening treatment technology, such as carburizing and nitriding, can also be used to form a hardened layer with higher hardness on the surface of the zero positioner, improve its wear resistance, and reduce the loosening of threads caused by wear.
3. Assembly and installation process technology
(I) Accurate assembly process
Accurate assembly process is the key link to ensure the anti-loosening performance of the zero positioner. During the assembly process, the assembly accuracy and matching clearance of each component need to be strictly controlled. For example, parameters such as the thread engagement length and tightening torque need to be precisely controlled. The appropriate thread engagement length can ensure the strength and stability of the threaded connection, while the accurate tightening torque can generate a suitable preload between the thread pairs. In addition, during the assembly process, attention should also be paid to the cleanliness of the components to prevent impurities from entering the thread pair and affecting its anti-loosening performance. At the same time, the use of appropriate assembly tools and methods, such as torque wrenches, fixed torque electric wrenches, etc., can ensure the accuracy and consistency of the tightening torque.
(II) Reasonable installation method
A reasonable installation method is also crucial to the anti-loosening of the zero positioner. During the installation process, it is necessary to select a suitable installation location and direction according to the use requirements and working environment of the zero positioner. For example, for zero positioners that are subject to large vibrations, it is necessary to avoid installing them near the vibration source as much as possible, or take effective vibration isolation measures. In addition, during the installation process, it is also necessary to pay attention to the connection method between the zero positioner and other components to ensure that the connection is firm and reliable. For some important zero positioners, a double insurance installation method can also be adopted, such as using threaded connection and mechanical locking structure at the same time to improve its anti-loosening performance.
4. Monitoring and maintenance technology
(I) Real-time monitoring technology
Real-time monitoring technology can detect signs of loosening of the zero positioner in time and take corresponding measures to deal with it. Common real-time monitoring methods include strain monitoring, vibration monitoring and temperature monitoring. Strain monitoring monitors the changes in its stress state in real time by pasting strain gauges on the surface of the zero positioner. When the zero positioner is loose, its stress state will change. The strain gauge converts this change into an electrical signal, which is analyzed and processed by the data acquisition system to determine whether the zero positioner is loose. Vibration monitoring monitors the vibration signal of the zero positioner during operation by installing a vibration sensor. When the zero positioner is loose, its vibration characteristics will change. By analyzing the vibration signal, the looseness can be discovered in time. Temperature monitoring uses a temperature sensor to monitor the temperature change of the zero positioner. When the zero positioner is loose, the temperature will rise due to increased friction. By analyzing the temperature signal, the working state of the zero positioner can also be judged.
(II) Regular maintenance technology
Regular maintenance is an important measure to ensure the long-term and stable operation of the zero positioner. Regularly check the threaded connection of the zero positioner, including tightening torque, thread wear, etc. For loose zero positioners, tighten them in time and check whether the threads are damaged. At the same time, clean and lubricate the zero positioner regularly to remove impurities and dirt on the surface and reduce friction and wear between the threads. In addition, the monitoring system of the zero positioner needs to be checked and calibrated regularly to ensure the accuracy and reliability of its monitoring data.