The latest development of manufacturing technology

2022-08-02
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The latest development of gear thread and spline manufacturing technology

gears (cylinder, cone, worm gear pair), threads, lead screws, worms, screws and splines are the key transmission parts and mechanical elements in the machinery manufacturing industry. Their manufacturing process level and product quality directly affect the assembly quality of various machinery. At present, China has more than 1000 machinery factories capable of mass producing gears, threads and splines, of which more than half are large and medium-sized enterprises (with more than 500 employees). These enterprises belong to dozens of industries, including aviation, aerospace, weapons, shipbuilding, electronics, textile machinery, petrochemical, transportation, railway, light industry, automobile, motorcycle, engineering machinery, metallurgical mining, machine tools, tools, instruments, meters, construction machinery, general machinery, lifting and transportation machinery, agricultural machinery, printing machinery, etc. The administrative affiliation of these enterprises is complex, but the manufacturing technology and equipment of gears, threads and splines have great commonalities

the manufacturing technology of gear thread spline is complex, the manufacturing equipment has high precision and is expensive. It is the most complex and expensive equipment in machine tools. Although it only accounts for 4% of the total number of machine tools, its investment accounts for more than 10%. Therefore, it is of great significance to predict its future development trend

I. The general trend of the application of gear thread spline is to reduce the development of

machine tools is based on the development of manufacturing technology. The general trend of the application scope of gear thread spline in mechanical products is to reduce the exhibition area by 22000 square meters. The reasons are:

1 With the wide application of numerical control technology and the maturity of built-in motor technology, less and less gear parts are used in the machine tool industry

2. The successful development and popularization of linear motor will gradually reduce the application range of ball screw in machine tools and measuring instruments

3. With the development of electronic control technology, the direct speed change of motor replaces part of gear speed change

4. The car hydraulic torque converter greatly reduces the number of gears in the gearbox

5. The development of electronic and quartz clocks almost completely replaced expensive mechanical clocks

6. The harmonic and cycloid pin gear reducers have replaced the gear reducers in many industries

as a conventional mechanical industry, the manufacturing industry of gear threads and splines is gradually being replaced by high-tech, and its application fields are becoming smaller and smaller. In 1785, Leonard Euler invented the involute, and in 1887 grant invented the gear hobbing machine, which made the gear enter the industrial application. In 1905, Niles company developed a gear grinding machine with endexing clearance. In 1924, reishauer company developed tap grinder and developed it into thread grinder. In 1934, Niles company manufactured the first generating gear grinder. In 1945, reishauer company developed the first worm wheel gear grinder. In the 1960s, the forming gear grinding technology was developed in Britain and Germany. In 1979, Fassler developed the internal gear honing technology. For half a century, gears with higher accuracy and quality have been widely used. In the next half century, the application of gear threads and splines will gradually decrease in the world, but will not die out. For developing countries such as China, the gear industry will also grow moderately

II. The latest development of manufacturing technology for gear threads and splines

1 Spline cold rolling process

ernst Grob company uses C6 and C9 series cold rolling mills to roll gears and spline shafts with m =3.5, and can roll helical gears. The replacement procedure time is 0.5min, the rolling head replacement time is 3min, and the fixture replacement time is 2min~10min. Due to the short adjustment time, even the small batch production of 20~30 pieces is very economical. The improved 12/14nc and krm12/14nc of C6 and C9 have higher production efficiency, accuracy and adjustability. It can be used in the whole process of rolling from bar stock to clutch housing of automatic transmission with internal and external teeth. It only takes 1.5min/piece to roll this part of 320. The thin-walled tube can be rolled into high-precision rack of steering gear in 25 seconds with zsm10 rolling mill

2. Diamond or CBN internal honing process

corning process adopted by Kapp company uses diamond or CBN internal engagement honing wheel to hone hardened tooth surface. The internal meshing honing machine has very high productivity and precision, and is especially suitable for hardened gears above rc65

3. Dry cutting process

liebherr uses carbide hobs or milling discs to dry roll cylindrical gears or dry mill bevel gears on lc82 hobbing machines and Gleason uses Phoenix series hobbing machines and bevel gear milling machines, which has extremely high productivity (increased by 30%) and precision, and the tool cost is reduced by 28%. And because the oil and coolant can not pollute the air and environment, it meets the requirements of environmental protection and belongs to a new pollution-free process

4. Solid grinding

edgetek's CNC grinding machine uses electroplating or ceramic bond, with the re introduction of new equipment and new technology CBN forming grinding wheel, to directly grind the spline shaft, turbine blade root or other surfaces from the bar. The hnc35s worm grinder of Klingelnberg company can grind the thread or worm directly from the bar with a grinding wheel

5. Grinding honing combined process

rzf toroidal worm grinding wheel of reishauer company is connected with an external honing process, which can grind low-noise gears with five levels of accuracy in about 1.5min/piece. The annual productivity of each rzf can reach 150000 gears, especially suitable for gear wheels of car transmission

6. Turn milling center

tnc42dgy eight axis turn milling center of Traub heckert company and mill turn M100 multi axis turn milling inspection center of WFL company can complete all machining of shells, discs and shaft zero conditioning chord parts in one installation. The machining time is reduced to one third to one fifteenth of the original decentralized process

all new manufacturing technologies will use machine tools and equipment, which have been greatly improved and developed from appearance to function

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