Gear couplings can be divided into three types according to the different axial tooth profiles of the outer gear sleeves, namely straight gear couplings, drum gear couplings and special drum gear couplings. Regardless of which type, the internal gear ring and the involute spur internal gear are the same except for the difference in the selection of the head clearance coefficient of the gear teeth.
The axial gear blank of the external gear sleeve of the spur gear coupling can be machined into two kinds of linear and circular arc shapes, and the index circle and the tooth root circle are both straight lines. The meshing form of this coupling is gradually The meshing of the internal and external teeth of the open cylindrical gear is exactly the same. The relative displacement between the two shafts is compensated by increasing the side clearance of the inner and outer teeth, but the amount of compensation is limited.
The tooth tip of the external gear sleeve of the drum-shaped gear coupling is processed into an arc, that is, the tooth blank is processed into a spherical surface. In the section of the tooth center plane and tangent to the pitch cylinder surface, the teeth form a drum shape, the so-called drum form Coupling. Its characteristics are:
- High load-carrying capacity, calculated by bending strength, under the same conditions, the torque transmitted by the spur gear coupling is increased by 15-30%;
- The structure is reasonable and the performance is reliable. Because the tooth side is drum-shaped, the contact condition of the axis is improved under a certain angle condition, thereby reducing the contact stress and eliminating the load concentration at the tooth end of the spur coupling. Eliminates edge extrusion and improves work performance.
- Good compensation performance. The tooth profile of the outer gear sleeve is drum-shaped, which increases the allowable relative deviation of the two shafts connected. The allowable inclination angle can reach up to 6 degrees, and 1.5°~2.5° is generally recommended.
Gear couplings have small radial dimensions, large carrying capacity, and are long used for shaft transmission under low-speed and heavy-duty conditions. High-precision and dynamically balanced gear couplings can be used for high-speed transmissions, such as gas turbine shafts. Transmission line. Since the angular compensation of drum gear couplings is greater than that of straight gear couplings, drum gear couplings are widely used at home and abroad. Straight gear couplings are obsolete products. Optional.
The more common gear couplings in the market include general structure gear couplings, drum gear couplings, nylon gear couplings and so on. Among them, there are many types of drum gear couplings and they are widely used.