Application field of ball screw: the basic concept of machining, development history, structure, application industry, motion principle of ball screw, machining status, turning, cyclone cutting, the reasons why ball screw is not smooth, the history of basic concept development is actually not very long, and the traditional screw has been poorly positioned and easily damaged. It was not until A.D. 1898 that people first tried to put steel balls between nuts and screws, and used rolling friction instead of sliding friction to solve the problems of poor positioning and easy damage. 1940 put the ball screw on the steering device of the car, which is a great revolution in the application of ball screw and gradually replaced the traditional Acme screw. Until recent years, ball screw has become one of the most widely used parts in industry. It turns out that only advanced industrial countries such as Britain, America, Germany and Japan can mass produce ball screws. Since 1982, Hefeng Precision Co., Ltd. has set up a factory to produce ball screws in Tanzi, Taichung County, officially opening the era when Taiwan Province Province can produce such high-precision parts by itself. Up to now, Taiwan Province Province has kept pace with other advanced industrial countries in the research and development and mass production capacity of ball screws, and has further become the main supply base in the world, which can be called one of the most remarkable achievements of the mechanical parts industry in Taiwan Province Province. Structural ball screw is mainly composed of screw, nut, steel ball, fixed seat, wiper and return pipe, which can be divided into external circulation, internal circulation and end plug circulation according to different circulation systems. Traditionally, the structure of ball screw is divided into two types: internal circulation structure (represented by circular commutator and elliptical commutator) and external circulation structure (represented by sleeve). These two structures are also the most commonly used structures. There is no essential difference in performance between the two structures, except that the size of the installation line of the internal circulation structure is small; The size of the external circulation structure installation connection pipeline is larger. At present, there are many kinds of ball screw pairs: 10, but the commonly used ones are: internal circulation structure; External circulation structure; End cover structure; Cover plate structure. Commutators with internal circulation structure have many shapes, but the common shapes are round and oval. Because the reverse channel of the circular ball is short, it is not as smooth as the elliptical structure. At present, the best commutator structure is elliptical inner channel structure. Because the ball reverser does not pass through the spiral tooth tip, which is similar to the external circulation structure, the influence of the chamfering error of the spiral tooth tip on the ball reverser is eliminated. However, due to the complicated manufacturing process, the popularity of this structure has been affected. The application of industrial ball screw has been widely used in positioning accuracy control of various industrial machinery, such as precision machine tools, industrial machinery, electronic machinery and transportation machinery. In addition to the above-mentioned mechanical applications, it is also used in the transmission of computer disk starters, the adjustment of aircraft wing lift, the control of propeller inclination, medical X-ray perspective cameras, etc., and its application range is extremely wide. The motion principle of ball screw is 1. According to the national standard GB/T 17587.3- 1998 and its application examples, the ball screw (which has basically replaced the trapezoidal screw at present, has been commonly known as the screw) is used to convert rotary motion into linear motion; Or converting linear motion into rotary motion, with high transmission efficiency and accurate positioning. 2. When the ball screw is the main body, the nut will be converted into linear motion with the rotation angle of the ball screw according to the lead of the corresponding specification, and the passive workpiece can be connected with the nut through the nut seat, thus realizing the corresponding linear motion. Processing Status At present, processing methods are mainly divided into chip processing (cutting forming) and chip-free processing (plastic processing). Traditional chip processing methods mainly include turning and cyclone milling, while non-chip processing methods mainly include cold extrusion and cold rolling. Chip processing of screw refers to the processing of screw by cutting forming, which mainly includes turning and cyclone milling. Turning refers to the use of different turning tools or other tools on the lathe, which can process various surfaces of revolution, such as internal and external cylindrical surfaces, internal and external conical surfaces, threads, grooves, end faces, molding surfaces and so on. The machining accuRacy can reach IT8-IT7, and the surface roughness ra value is 1.6~0.8. Turning is often used to process uniaxial parts, such as straight shaft, disk and sleeve parts. Cyclone cutting Cyclone cutting (cyclone milling) is an efficient thread machining method, which is suitable for large-scale thread rough machining. Its process is to use cemented carbide cutter to mill threads at high speed, which has good cooling and high production efficiency. This method can be used to cut threads with low precision for ~ times. The thread processing method of milling threads from the workpiece with the forming cutter head installed on the high-speed rotating cutter head is named because of the high milling speed and the whirlwind flying of chips. Generally, the accuracy of cyclone cutting trapezoidal thread can reach 7~9 grades (JB2886-8 1), and the surface roughness Ra5~0.63. Causes of unsmooth ball screw In recent years, more and more ball screws have been used in various machines to meet the requirements of high-precision and high-performance equipment. Ball screw has become one of the most widely used rotating parts. In NCN machinery, ball screw can improve its positioning accuracy and prolong its service life. In traditional machinery, the ball screw has gradually replaced the internal thread of Echo. Ball screw is usually equipped with pre-pressure to eliminate the clearance during mechanical operation, but if the ball screw is improperly installed and runs unsteadily, its high precision and long life will not be displayed. 1. Improper installation of bearing: (1) Rough surface of screw or nut bead; (2) The roundness of steel ball, screw or nut is out of tolerance; (3) Lead error or pitch diameter deviation of the screw or nut; (4) Improper assembly of oil return pipe; (5) Uneven size or hardness of steel balls; 2. Other foreign objects enter the steel ball track: (1) The track is blocked by damaged packaging materials: the ball nuts and screws are packed with a lot of packaging materials and non-proliferation bags during shipment. If proper standard procedures are not followed when packing or arranging steel balls, foreign objects or other broken objects may block the track of steel balls, causing them to slide instead of running normally or even get stuck; (2) The machining debris enters the orbit. If the ball screw is not equipped with a wiper when it is installed, machining debris and dust will easily accumulate and block the steel ball track, resulting in poor finish, reduced precision or shortened service life. 3. Overtravel: Overtravel will cause damage, depression or even fracture of the oil return pipe, which will cause the steel ball to fail to work normally. Under such harsh conditions, the surface of the screw or nut bead may peel off. Overtravel problems are likely to occur in the setting of the machine, the failure or collision of the limit switch. In order to prevent further damage of the ball screw, it must be inspected and repaired by the manufacturer before reinstalling the ball screw. 4. Damage to the oil return pipe: If the oil return pipe is severely impacted during installation, the oil return pipe may be sunken or have the above problems. V. Eccentricity: If the nut seat and the bearing seat are not concentric, radial load will be generated. When the deviation between them is too large, the screw will bend. Usually, if the eccentricity is not very serious, it will not cause obvious bending, but abnormal wear will continue to occur, which will reduce the accuracy of the screw. The higher the preload set by the nut, the higher the requirement for eccentricity accuracy. 6. Improper combination of nut and nut seat: When the nut is installed, inclination or eccentricity will cause abnormal load and make the voltage unstable when the motor is running. Seven, when dealing with the damaged ball screw.