Auxiliary screw hydraulic screw press

The transmission principle of the auxiliary screw hydraulic screw press was invented by the German Hussen Company, which has successfully developed the HSPRZ hydraulic screw press with a forging force of 125MN. Because there is a certain friction loss between the auxiliary screw and the copper auxiliary nut affecting the transmission efficiency of the whole machine, the company turned to the development of HSPRZ series hydraulic motor screw presses.

Due to the poor performance of the hydraulic motor screw press in China, and the easy manufacturing of the cylinder and auxiliary screw pair, from 1974 to 1978, Professor Huang Shuhuai of Huazhong University of Science and Technology and his research team combined with China's national conditions, used anti-friction engineering plastics as auxiliary nuts, making this transmission scheme feasible.

The achievement won the National Science and Technology Conference award in 1978, among which, the auxiliary nut made of cloth phenolic resin laminate material and the auxiliary screw hydraulic drive system composed of the integrated valve developed for the first time in China won the third prize of national technical invention in 1983. After the application of several blade and gear forging enterprises, the precision forging production can be better, but it also shows that the return speed of the slider is slow, the number of strokes is not easy to improve, so the production efficiency is difficult to improve. The reason is that the annular area below the piston is small, resulting in small return force, and more difficult to solve.

Small and medium-sized gear driven electric screw press and manual production line

From 1980 to 2006, Professor Huang Shuhuai and his research team carried out research and development and continuous improvement of gear-driven electric screw presses, and successfully developed J58K 160-1600T series products. The structure principle of J58K gear driven electric screw press is shown in Figure 1. The transmission process and working principle is that the motor drives the flywheel and the screw fixed together with the flywheel through the pinion for positive and negative rotation, the screw drives the slider to move up and down, the forging function is completed when the downward movement, and the slider returns to the initial position when the upward movement.

Figure 1 J58K gear driven electric screw press structure schematic

Compared with the traditional friction press, the performance of this electric screw press has the following characteristics:

(1) The small gear is made of cloth phenolic resin, and the contact friction coefficient between the large steel gear (flywheel) is only 1/6 of the two steel gears, and because the pinion material is light and the moment of inertia is small, coupled with the short transmission chain, the transmission efficiency is greatly improved, and it also runs when working, comprehensively saving more than 30% of electric energy, and increases with the increase of the tonnage of the press.

(2) The gear drive is a rigid transmission system, and the transmission speed ratio is stable, so the stroke of the slider and the forging force can be accurately controlled, which is conducive to improving the service life of the mold.

(3) Its force and energy characteristics are between the static load of the hot die forging press and the dynamic load of the die forging hammer, and close to the dynamic load characteristics, coupled with the use of long sliding block and guide rail device, strong anti-biased load ability, wide range of process application, especially suitable for warm and hot precision forging process.

(4) It can establish semi-automated or automated production lines with auxiliary equipment such as heating, billet making and cutting and punching through robots or special manipulators, which can effectively improve the stability of the process and the consistency of forging quality.

⑸ Simple structure, easy to use, easy to maintain. Its manual production line is the billet by medium frequency induction heating → billet making → pre-forging → final forging → cutting, punching → correction, the whole process is manually operated.

(6) J58K gear driven electric screw press and manual production line in Hubei, Zhejiang, Jiangsu, Shanghai, Guangdong, Shandong, Chongqing, Sichuan, Henan and Jilin provinces and cities automobile, tractor, construction machinery, mining machinery and power fittings and other parts manufacturing enterprises to promote the application, the production of more than 100 kinds of forgings. According to rough statistics, there are about 1,500 screw presses used in the forging industry in the country, and this type of press accounts for about 50%, which has created good economic and social benefits for enterprises.

Large and medium gear driven electric screw press and automatic production line

From 2007 to 2016, our R & D team inherited Professor Huang Shuhuai's research and development and application of geared electric screw press, based on the development of 2500t and 4000t large geared electric screw press, during which a total of more than 20 sets of J58K-2500 and 5 sets of J58K-4000 were developed. Hubei Sanhuan Forging Co., Ltd. uses the first J58K-2500 electric screw press (FIG. 2) to produce rail chain joint precision forgings (FIG. 3) through the "flattening, pre-forging and final forging" small flash precision forging process, which increases the material utilization rate to more than 90% and significantly saves energy. Xuzhou XCMG Railway Equipment Co., Ltd. and other units use J58K-1600 and J58K-2500 electric screw presses to produce large and medium-sized forgings such as support wheels, large cylinders, bearing rings, dredge support seats, among which large cylindrical ring gear billet has good material saving and energy saving effect. Hubei Sanhuan Forging Co., Ltd. uses the first J58K-4000 electric screw press (FIG. 4) to produce disc steering knuckle precision forgings (FIG. 5) through vertical small flash forging process. Compared with the horizontal open die forging on the hot die forging press, the material utilization rate is increased from 72% ~ 73% to 86% ~ 88%.

Figure 2 J58K-2500 electric screw press

Figure 3 Chain link precision forging

Figure 4 J58K-4000 electric screw press

Figure 5 Disc steering knuckle precision forging

At the same time, according to the rapid development of foreign automatic forging technology and domestic market demand, the automatic forging production technology is developed in time. First of all, according to the structure characteristics of the forgings planned by the user, the precision forging process plan is formulated. Based on this, the tonnage of the required main engine and the reasonable configuration of heating, billet making, trimming and punching, calibration equipment and robot are emphatically studied. Optimized layout of equipment and robot based on precision forging process; Make timing planning of all equipment and robot movements in the production line based on the production time requirements; Automated production control system software development.

In the past 10 years, based on these key technologies, the company has established more than 70 automatic precision forging production lines for automotive parts and other manufacturing industries with geared electric screw presses as the main engine and robot operation. Among them, 27 valve forging production lines have been established for MAHle three-ring Valve Drive (Hubei) Co., LTD., which is a joint venture company controlled by the internationally renowned German Mahle Valve Drive Company. At the beginning of the joint venture, MahLE originally intended to use the CNC electric screw press produced by German Lasco company, German robots and valve forging process and mold. After nearly a year of investigation, it is found that the performance of J58K electric screw press is comparable to that of Lasco electric screw press, but the price is only 1/3 of that of Lasco. The closed precision forging process of valve developed by Huazhong University of Science and Technology and the advanced technology of steel-bonded cemented carbide die core and stepped prestressed composite die are advanced. All these equipment and technologies are made in China. At present, the annual output of high-end valves is more than 80 million, becoming the largest valve enterprise in Asia, compared with traditional equipment and technology: The material utilization rate is increased by more than 12%, the pass rate of forgings is increased from about 95% to nearly 100%, and the die life is increased to 180,000 pieces. In order to strictly control the accuracy of valve forgings, the general control is used to 150,000 pieces, and the technical and economic efficiency is significant. Three automatic production lines of warm forging of straight bevel gear for automobile were established for Qingdao Samsung Precision Forging Gear Co., LTD. The tooth shape accuracy of the straight bevel gear differential produced was 8 ~ 9, which met the requirements of direct loading.

Research and application of direct drive electric screw press

In 2016, our company developed a direct drive electric screw press. Due to the superior performance of the direct drive electric screw press, the first prototype J58ZK-500 (Figure 6) was immediately adopted by Zhejiang Yuejin Nonferrous Metals Co., LTD., after debugging. To the existing J58 ZK 400/500-215/315 / / 630/1000/1600 type use by the client, the customer reflect good. At present, the direct drive electric screw press with larger tonnage is being developed to meet more user requirements.

Figure 6 J58ZK-500 electric screw press

Closing remarks

According to the "Made in China 2025" proposed by the manufacturing industry along the digital, information, networking, intelligent direction of development, the development of CNC electric screw press as the host intelligent automatic forging production line, and even intelligent automatic professional forging factory. Its characteristics are that in the process of production and operation, around the structural characteristics of forging, dimensional accuracy and quality requirements, physical properties (mechanical, electrical, magnetic conductivity) and size specifications of forging materials, press slider die forging forming speed, displacement, forging die working conditions, lubrication conditions and forging temperature and other factors change or fluctuation, the entire intelligent precision forging system with automatic precision forging production line as the carrier. It has the function of self-learning, self-adaptation and self-adjustment to ensure that highly qualified precision forgings are obtained to achieve the purpose of improving quality and efficiency.