Gears can be classified into cylindrical gears, bevel gears, worm gears, and worm wheels.
(Gear reducer)
Types and characteristics of cylindrical gears
spur gear
The shafts of the large and small gears are parallel to each other; the rectangular lines of the gear teeth are parallel to the gear shafts; when the external gears mesh, the two gears rotate in opposite directions; when the internal gears mesh, the two gears rotate in the same direction; the tooth profile can be made into ordinary teeth, short teeth, and deflection teeth.
Cylindrical helical gears
The large and small gear shafts are parallel; in external meshing transmission, the two gears rotate in opposite directions; in internal meshing transmission, the two gears rotate in the same direction; the tooth profile can be made into ordinary teeth, short teeth, and variable positions; the rectangular line of the gear teeth is inclined at an angle relative to the gear shaft; the meshing transmission is more stable and stronger than that of spur gears.
helical gears
The shafts of the large and small gears can be parallel, intersecting, or perpendicular in space; the rotation directions of the large and small gears can be the same or opposite; the rotation angles of the large and small gears can be equal or unequal; when the rotation angle of the small gear is large enough, it will turn into a tadpole.
Gears and racks
The gear meshing with the rack can be a spur gear or a helical gear, possessing the characteristics of either. Rack and gear transmission converts rotation into linear or linear motion. When the gear diameter is infinitely large, a rack is formed.
Types and characteristics of bevel gears
Straight bevel gears
The two axes of the large gear and the small gear intersect at the apex of the cone; when the cone angle of the large gear pitch is equal to 90°, it becomes a planar gear; when it exceeds 90°, it becomes an internal bevel gear.
Spiral bevel gears
The tooth line is inclined, tangent to the circle, and does not intersect the top of the cone; the large and small gears are equal in opposite directions; it is more stable than a straight bevel gear drive.
Spiral bevel gears
The transmission is smooth and has high power, making it suitable for low-speed transmission; the large and small gears rotate at equal angles but in opposite directions; the two gear shafts intersect at the top of the cone; the spiral bevel gear consists of spiral teeth, which extend into cycloidal teeth and gradually open into straight teeth.
Types and characteristics of worms and worm wheels
Cylindrical worm and worm wheel
Archimedes worm gear
The tooth profile on the axial section of the worm gear is straight.
linear worm gear
The tooth profile of the worm gear in the tangential plane of rotation is a straight line.
Involute worm gear
The tooth profile on a plane parallel to the worm shaft and tangent to the base cylinder is a straight line.
Curved worm and worm wheel
High efficiency, good oil film formation; high load-bearing capacity; complex manufacturing and assembly; also known as a spherical worm gear pair; tooth profile is divided into prototype plow and improved plow. The purpose of the modification is to make the worm gear easier to form an oil film in the transmission.
Gear transmission device
Depending on whether the shaft position of each gear is fixed, gear transmissions can be divided into two basic types: planetary gear systems and fixed-shaft gear systems.
Fixed-axle wheel systems include planar fixed-axle wheels and spatial fixed-axle wheels, where the geometric axis position of all gears is fixed during transmission.
Based on their degrees of freedom, planetary gear systems can be divided into planetary gear systems and differential gear systems. The differential gear system of a rotating gear system has two degrees of freedom.
