Lead screw: high-precision equipment + process is the key, low localization rate

3500/33 Lead screw function: The main function is to convert rotating motion into linear motion, or to convert torque into axial repeated force. Screw classification: including ball screw and planetary roller screw. Ball screw and roller screw appear in the same era, the difference between the two is as follows: ball screw: simple structure, high transmission efficiency, can be greater than 90%; The load transfer element is ball, point contact, the main advantage is that there are many contact points to support the load, with higher impact resistance. Planetary roller screw: complex structure, transmission efficiency is generally less than 90%; The load transfer element is the threaded roller, which is a typical line contact, in the case of the need for large loads, especially in the case of space constraints, when a large load is required, the planetary roller screw will be selected, which is generally 2 to 3 times larger than the load of the ball screw pair of the same specification, and the minimum optional lead of the medium and small specifications of the planetary roller screw is smaller.

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Reverse planetary roller lead screw: The forward planetary roller lead screw is characterized by a screw rod – short nut plus a spiral raceway, which realizes linear movement through the rolling of the roller on the lead screw shaft. Using the combination form of its long nut and short lead screw, the long nut can be designed as a motor rotor, which is easy to realize the design of electromechanical fusion linear actuator, small size, compact structure, and suitable for humanoid robots. In the reverse planetary roller screw mechanism, the nut only rotates peripherally and does not move axially, the screw only moves axially and does not rotate peripherally, and the roller has both rotation and revolution. The reverse planetary roller screw achieves a higher load rating with a smaller lead, thereby reducing drive torque.

Lead screw production requires high-precision equipment and process accumulation. The lead screw has the characteristics of high precision, reversibility and high efficiency, and it has high requirements in terms of precision, strength and wear resistance, so the processing requirements of each process from blank to finished product are relatively high.

3500/33 There is still a large space for the localization rate of screw, and a number of domestic manufacturers with certain competitive advantages have appeared. In the international market, the high-end ball screw market is mainly occupied by European, American, Japanese and South Korean companies, including Japan Seiko, Bosch Rexlot, Kuroda, Schaeffler Group, etc. In recent years, with the progress of science and technology, China’s ball screw industry has also emerged a number of excellent enterprises with a certain competitive advantage, such as Nanjing process equipment, Shandong Bote Seige, Yintai Technology, Shandong Huazhu machinery, Shaanxi Hanjiang machine tools and other enterprises, while Hengli hydraulic, Best and other companies are also involved in the field of screw.