Classification of gears
Gear The gears can be classified according to the tooth shape, the gear profile, the tooth shape, the surface of the teeth and the manufacturing method.
Gear The tooth profile of the gear includes the profile curve, the pressure angle, the tooth height and the displacement. Involute gears are easier to manufacture, so the use of modern gear, involute gears accounted for an absolute majority, and cycloidal gears and arc gear applications less.
Gear In the pressure angle, the small pressure angle gear bearing capacity is small; and large pressure angle gear, although the carrying capacity is high, but in the same transmission torque bearing load increases, so only for special circumstances. The gear teeth have been standardized, generally using standard tooth height The advantages of variable gears have been all over the various types of machinery and equipment.
Gear In addition, the gear can be divided into cylindrical gears, bevel gears, non-circular gears, racks, worms and worms according to their shape; according to the shape of the tooth is divided into spur gears, helical gears, herringbone gears, curved gear; Surface is divided into external gears, internal gear; according to the manufacturing method can be divided into casting gear, cutting gear, rolling gear, sintering gear.
Gear The manufacturing material and heat treatment of the gears have a significant effect on the load carrying capacity and size of the gears. Before the 1950s, gears were made of carbon steel, and in the 1960s, alloy steel was used instead of surface hardened steel in the 1970s. According to the hardness, tooth surface can be divided into two kinds of soft tooth and hard tooth surface.
Gear Soft tooth surface bearing capacity is low, but the manufacturing is relatively easy, running good, and more for the transmission size and weight without strict restrictions, and small production of general machinery. Because the pair of gears, the heavy wheel load heavier, so in order to make the size of the gears working life roughly equal, the small tooth surface hardness is generally higher than the big round.
Gear Hardened gear bearing capacity is high, it is fine after the gear, and then quenching, surface hardening or carburizing quenching to improve the hardness. However, in the heat treatment, the gear will inevitably produce deformation, so after the heat treatment must be grinding, grinding or fine cutting, in order to eliminate the deformation caused by the error, improve the accuracy of the gear.
Gear Manufacture of gears commonly used steel with quenched and tempered steel, hardened steel, carburized steel and nitriding steel. Cast steel is slightly lower than the forged steel and is often used in larger gears. The mechanical properties of gray cast iron are poor and can be used in light-driven open gear drive. Ductile iron can partially replace steel for gears. In the light load and the requirements of low noise, and its matching gear generally good thermal conductivity of steel gear.
Gear Future gears are moving forward, high speed, high precision and high efficiency, and strive to small size, light weight, long life and economical and reliable.
Gear The development of gear theory and manufacturing process will be a further study of the mechanism of tooth damage, which is based on the establishment of reliable strength calculation method, is to improve the gear carrying capacity, extend the gear life of the theoretical basis; development to circular tooth profile as the representative The new gears of the gears and the new gears of the gears are studied. The elastic deformation, manufacturing and installation errors of the gears and the distribution of the temperature fields are studied, and the gears are modified to improve the smoothness of the gears. So as to increase the contact area of the teeth, thereby improving the load carrying capacity of the gear.
Gear Friction, lubrication theory and lubrication technology are the basic work in gear research. It is not only to improve the bearing capacity of tooth surface by studying the theory of elastic fluid dynamic lubrication, to promote the use of synthetic lubricating oil and the proper addition of extreme pressure additives in oil. Can also improve the transmission efficiency.