Bevel gear introduction and manufacture technology
Bevel gears are also called conical gears. For transmission between intersecting shafts. Compared with cylindrical gears, the transmission direction can be changed. The single-stage transmission ratio can reach 6 and the maximum is 8.
1. Straight and helical bevel gears are simple in design, manufacture and installation, but they are relatively noisy and are used for low-speed transmission (<5m / s); straight bevel gears can transmit power up to 370 kilowatts and a peripheral speed of 5 meters /second. The helical bevel gear drive runs smoothly and the gear bearing capacity is high, but it is difficult to manufacture and has fewer applications.
2. The curved bevel gear has the characteristics of stable transmission, low noise and large bearing capacity. It is used for high-speed and heavy-load occasions. Curved bevel gear transmission runs smoothly, the transmission power can reach 3700 kilowatts, and the peripheral speed can reach more than 40 meters per second.
Bevel gears are divided into straight bevel gears and spiral bevel gears.
Processing of bevel gears
The bevel gear is mainly used for the transmission where the two shafts intersect. The angle between the two shafts is usually 90 °, which can also be less than 90 °. Bevel gears are generally processed on special machine tools such as bevel gear planers. In the absence of bevel gear special machine tools, bevel gear milling cutters can be used on milling machines, which use forming tools and indexing devices to process on the milling machine. Due to the indexing error and tool installation error, generally only gears with 9-10 grade accuracy can be processed. In addition, the process requires multiple discrete tooth splits and low productivity. It is only used for gears with low machining accuracy in single-piece small batch production and repair work.
Bevel gear manufacturing process
1. First, use the principle of rolling to make the processed gear and the imaginary shovel gear repeatedly perform opposite rolling operations. The cutter is a planer with two linear cutting edges, which is mounted on the tool holder and reciprocates with the tool holder. Linear motion.
2. The knife holder is installed on the cradle to form an imaginary shovel gear. The imaginary shovel gear swings from top to bottom and from top to bottom around its axis. The processed gear is mounted on the main shaft of the split gear box. The split gear box is moved to make the bevel top of the processed gear and the imaginary spade gear cone Coincide with each other, and make the root angle of the tooth parallel to the surface through which the tip passes.
3. When cutting the teeth, the cradle and the gear to be processed make coordinated and coordinated movements around the axis of the axis, that is, as the two bevel gears mesh, under this installation, the gear is processed.
4. The axis line and the rotary axis line of the cradle intersect at one point, and this intersection point is the center of the machine tool. This mutual movement allows the planer to plan the correct involute tooth profile.
According to the number and the modulus of the workpiece, the gears can be planed by single or double split method. For single-piece and small-lot production, single split gears are generally used for planing gears.
