Processing of various gears and introduction history of CNC machine tools

- Dec 13, 2019-

Exchange gears for mechanical transmission chain; use programmable control device with fault diagnosis function to control cutting cycle to change cutting parameters; develop digital restraint non-circular gear shaper to adapt to gear hobbing machine; electronic sensor on gear hobbing machine to detect motion error of drive chain And automatically feedback compensation errors.


In 1884, the United States Bill Graham invented a single planer to produce straight bevel gear gear planers; in 1900, the United States Bill designed a double cutter milling straight bevel gear machine.

Because of the necessity of the automobile industry, the United States manufactured a straight-bevel gear planer with two planers in 1905, and it was made into a bevel gear milling machine in 1913. In 1923, a quasi-involute bevel gear milling appeared. Gear machine; developed in the 1930s to straighten bevel gears to form a broaching machine, which is mainly used in automobile differential gear manufacturing.


In the 1940s, in order to meet the needs of the aviation industry, the arc bevel gear grinding machine was developed. In 1944, the Swiss Oerlikon company made an extended epicycloid bevel gear milling machine; since the 1950s, it has developed a double cutter body combined end milling cutter to process the extended epicycloid bevel gear milling machine. .

Gear processing machine tools are mainly divided into two categories: cylindrical gear processing machine tools and bevel gear processing machine tools. Cylindrical gear processing machine tools are mainly used to process various cylindrical gears, racks and worm gears. Gear hobbing machines, gear shaping machines, gear milling machines, and shaving machines are commonly used.


The hob for the hobbing machine is rough, finely machined with straight teeth, helical teeth, herringbone gears, worm gears, etc., with a wide processing range, which can achieve high precision or high productivity. And other toothed parts of helical gears, mainly used for processing internal gears of multiple gears; forming milling cutters for gear milling machines are processed according to the indexing method, and are mainly used for processing special toothed instrument gears; gear type razors for shaving machines High-efficiency machine tools for finishing gears; grinding wheels for gear grinding machines, high-precision machine tools for hardened cylindrical gears or gear tool tooth surfaces; honing machines use the sprocket wheels to freely mesh with the gears being processed to eliminate burrs on hardened gears and other tooth surfaces Defective machine tools; gear squeezers use high-hardness non-cutting edge squeeze wheels to freely mesh with the workpiece, grind small unevenness on the tooth surface to improve accuracy and smoothness; gear chamfering machines round the ends of the internal and external sliding gear teeth Machine tools, production gearboxes and other gear shifting mechanisms are indispensable for processing equipment. Cylindrical gear processing machines also include gear hot rolling mills and gear cold rolling mills.

The bevel gear processing machine is mainly used to process bevel gear teeth such as straight teeth, helical teeth, and extended trochoidal teeth.

Straight bevel gear gear planer uses paired planer blades to produce coarse and fine-cut straight bevel gear machine tools according to the development method. There are machine tools that can also plan helical bevel gears, which are most widely used in small batch production.

The double cutter straight bevel gear milling machine uses two cutter teeth staggered milling cutters to mill the left and right tooth surfaces of the same cogging according to the development method, which has a higher production efficiency and is suitable for batch production. Due to the relative movement of the milling cutter head and the workpiece in the toothless length direction, the bottom of the cogged groove is arc-shaped, and the tooth width of the processing module is limited. This machine tool can also be equipped with automatic loading and unloading devices to achieve single machine automation.

A large-diameter broaching cutter head of a straight tooth bevel gear broaching machine makes one cogging machine from the solid wheel blank by forming. The bevel gear cutting machine tool has the highest productivity. Due to the complexity of the tool and the high price, a special cutter head is required for each type of workpiece, which is only suitable for mass production. Machine tools are generally equipped with automatic loading and unloading devices.

Spiral bevel gear milling machine uses arc bevel gear milling cutters to roughen and finish the curved bevel gear hypoid gear machine according to the forming method. There are variants such as precision cutting machine and roughing machine gear drawing machine.

Spiral bevel gear grinding machine is used to grind hardened spiral bevel gears to improve accuracy and smoothness. The structure is similar to that of spiral bevel gear milling machines, but it uses a grinding wheel instead of a milling cutter and is equipped with a grinding wheel dressing It can also grind hypoid gears.

The extended epicycloid bevel gear milling machine uses an extended epicycloid bevel gear milling cutter head, or a double-blade combined end face milling cutter head, which continuously divides the teeth according to the development method. During tooth cutting, the workpieces of the milling table of the cradle are continuously rotated, and the workpiece is reciprocated once by the cradle as the feed motion. The continuous rotation of the milling cutter workpiece allows the workpiece to obtain a continuous index of a certain number of teeth, and forms a tooth length curve. The cradle's rotating workpieces are combined with the accompanying motions to produce a convergent motion, so that the workpieces get a tooth-shaped curve.

The taper hob for quasi-involute bevel gear milling machine is used to continuously index the gear cutting machine according to the development method. When cutting teeth, the taper hob first cuts with the large end, then cuts with its smaller diameter. In order to ensure the same cutting speed throughout the cutting process, the machine tool relies on the stepless speed change device to control the hob speed to cut the teeth. For continuous rotary motion, machining a workpiece, the rocking table reciprocates once. The rotation of the work piece of the cradle generates a generating movement through the differential mechanism, so that the work piece obtains a tooth profile curve with a constant height along the tooth length.

The supporting equipment of bevel gear processing machine tools are grinding milling cutters, broaching cutters, blade sharpeners, paired bevel gear grinding machines, and testing of the bevel gear meshing contact conditions. The bevel gear rolling inspection machine prevents the heat treatment of the teeth from being deformed and quenched. Bed and so on.

 Gear processing machine tools are widely used in various machinery manufacturing industries such as automobiles, tractors, machine tools, engineering machinery, mining machinery, metallurgical machinery, petroleum, instruments, aircraft and spacecraft.

The gear processing machine tool processes various cylindrical gears, bevel gears and other toothed parts. There are various specifications of gear processing machine tools, including small machine tools for processing gears with a diameter of a few millimeters, large machine tools for processing gears with a diameter of more than ten meters, and high-precision machine tools for processing precision gears with high-efficiency machine tools for mass production.

Ancient gears were shaped by hand. In 1540, when Toriano in Italy manufactured clocks, a tooth cutting device using a rotary file was made; in 1783, Rene, France, made a machine tool using a milling cutter gear, and had accessories for cutting internal gears; around 1820 , British White produced the first machine that can process both cylindrical gears and bevel gears. Machine tools with this performance developed again in the second half of the 19th century.

In 1835, Whitworth in the United Kingdom obtained a patent for a worm gear hobbing machine; in 1858, Schiller obtained a patent for a helical gear hobbing machine; after several improvements, it was completed in 1897 by Pforte, Germany, with a differential gear hobbing machine. Gear problem. After making gear-shaped gear shaper, American Ferros made the gear shaper in 1897.

At the beginning of the twentieth century, due to the necessity of the automobile industry, various gear grinding machines came out one after another. Around 1930, the United States made a gear shaving machine; in 1956, it made a gear hobbing machine. Since the 1960s, modern technology has been applied to some advanced cylindrical gear processing machine tools. For example, large-scale machine tools use digital displays to indicate the depth of tooth cutting. The gear hobbing machine and gear shaping machine use electronic servo control systems.


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