To see what type of equipment is connected to the two shafts of the reducer, coupling reducer selection coupling is the main consideration of the required transmission shaft speed of high and low load size, the installation progress of the two parts connected, the smoothness of rotation, price, etc., and according to the characteristics of various types of couplings, choose a suitable coupling type. Generally speaking, the transmission coupling is divided into 2 kinds of universal, involute spline 30 degrees pressure angle 20 degrees ordinary teeth. According to the formula to spline is - the number of teeth plus 1 multiplied by the modulus equal to the shaft head outside diameter teeth minus 1 in multiplied by the modulus equal to the internal tooth diameter.
　　The outer teeth are divided into straight teeth and drum teeth two kinds of tooth shape, the so-called drum teeth that is the outer teeth made of spherical, spherical center in the gear axis, tooth side clearance is larger than the general gear, drum tooth coupling can allow a larger angular displacement (relative to the straight tooth coupling), can improve the contact conditions of the teeth, improve the ability to transmit torque and extend service life. Selection of coupling type: The selection of coupling type depends on the coupling type of the main and driven end on the shaft, generally using the key coupling, in order to unify the key coupling type and code, in the provision of seven types of keyway type.
　　Tooth type coupling is to rely on two table teeth and a central tube in series assembly to transfer torque, if the motor and reducer spacing is considered too long and the special use of such couplings instead. Under normal circumstances, there will be no broken teeth, satisfying the requirements of the operating characteristics of continuous rolling mills; the drum tooth coupling can meet the requirements of the mill tampering roll rolling expansion is very convenient; the use of cleaning and other features. Wrapped along the end of the two halves of the coupling when the coupling rotates, the disk and the ring sleeve rotate together, and under the action of centrifugal force with the half-coupling concentric with the ring sleeve.
　　The flexible pin-tooth coupling is made of a number of non-metallic pins placed in the counterbore between the two coupling halves and the inner surface of the outer ring, and the torque is transmitted through the pins to realize the coupling of the two coupling halves. The flexible pin-tooth coupling has the performance of compensating the relative offset of the two shafts, and is suitable for medium and large power transmission, and is not applicable to the work parts where vibration damping is required and noise needs to be strictly controlled.
　　Fast transmission speed: based on the characteristics of economy, drum gear coupling has the characteristics of rigid, flexible and non-elastic, not suitable for machinery requiring vibration damping, cushioning and two-shaft alignment.