Description of gear coincidence degree, longitudinal coincidence degree and end-face coincidence degree

XNUMX. Description of gear coincidence:

Definition of coincidence degree: Gear transmission depends on each pairgearThe ratio of the length of the actual meshing line to the pitch of the base circle is achieved by the sequential meshing.As a measure of gear carrying capacity and transmission stability.The greater the degree of coincidence, the better the smoothness of the transmission.

The coincidence degree has end-face coincidence degree and longitudinal coincidence degree.The sum of the end-face overlap rate and the longitudinal overlap rate is called the total overlap rate.Compared toSpur gear, The coincidence of helical gears is larger.Generally, the coincidence degree of the helical gear is above 1.5, and it is easy to reach 2 or more, and the maximum can reach 3 or even 4.

Generally speaking, when the total coincidence rate is an integer of 2 or 3, the working noise is low.In terms of strength, if the coincidence degree is greater than 1, continuous meshing can be achieved.The degree of coincidence is high, the load on each tooth is dispersed, and the gear becomes stronger.

To keep the two gears continuously and smoothly in transmission, it is necessary to ensure that before the end of the first pair of tooth profiles (at least at the same time), the latter pair of tooth profiles have entered the mesh, otherwise the transmission will be interrupted.

In order to enable continuous transmission of gears, it should be ensured that when the previous pair of gears are out of mesh, the latter pair of gears will enter into meshing, so the coincidence degree should be greater than 1.

The coincidence degree reflects the average of the number of gear tooth pairs participating in the meshing at the same time. The greater the coincidence degree, the better the continuity and smoothness of the gear transmission.

XNUMX. Longitudinal coincidence of gears:

Longitudinal coincidence is the quotient of the tooth width of a helical gear like a helical gear divided by the axial tooth pitch.

XNUMX. Coincidence degree of gear end faces:

The end-face coincidence degree is the quotient of the meshing length on the end-face line of action divided by the base circle tooth pitch.

For example, if the end-face coincidence ratio is 1.5, the single tooth and two teeth alternately mesh when the gear rotates.

If the end-face coincidence ratio is 2, the two teeth are always in meshing state at the same time.

For more information about gear coincidence, longitudinal coincidence and end-face coincidence, please ask EP technicians for help, thank you!