The cycloidal pinion transmission refers to a planetary gear transmission composed of a pair of internal gears and an output mechanism whose outer gear tooth profile is a metamorphic cycloidal wire and the internal gear tooth which is a round pin.

Cycloidal Pinion Drive

Except for the tooth profile of the gear, the other structure is the same as the planetary gear drive with less tooth difference.

The transmission ratio of the cycloidal pinion planetary reducer is about 6~87, and the efficiency is generally 0.9~0.94.

The circle is rolled on the base circle. If it is larger than r1, the pointed drawn is a long outer cycloid;

If it is less than r1, the pointed drawn is a short outer cycloid;

Use any point on one of these cycloids as the center of the circle, draw a series of circles with the radius of the needle tooth rZ, and then make a curve tangent to the series of circles, and get the corresponding long swing line profile or short cycloid profile.

Among them, the short outer cycloidal profile is the most widely used.

When the entire short outer wobble is used as the tooth profile, the difference between the pin wheel and the cycloidal wheel is only one, and theoretically, half of the number of teeth of the pin wheel is simultaneously meshed with the cycloidal tooth.

However, if a partial curve is used as the tooth profile, a cycloidal pinion transmission with two tooth differences and three tooth differences can be obtained.

When a part of the long outer trochoid is used as the tooth profile, the tooth profile is similar to the circle and has little difference with the shank radius, so it can be replaced by its close arc.

The advantages of cycloidal pinwheel transmission are large transmission ratio, compact structure, high efficiency, stable operation and long service life.

Cycloidal pinwheel planetary transmission has the advantages of large transmission ratio, compact structure, large bearing capacity and high transmission efficiency. It is widely used in machinery, mining, metallurgy, chemical, textile, national defense and other industrial fields.

The transmission has a large number of meshing teeth, significant error average effect, high transmission precision, no flexible members, high torsional rigidity, and has received extensive attention in the field of precision transmission in recent years.

In addition, the cycloidal gear pump based on the principle of cycloidal pinion planetary transmission has received attention from various countries due to the smooth meshing process, with small pulsation and low noise.

The theory of cycloidal pinion planetary meshing transmission is generally described as: a pendulum method and an internal pendulum method form a short cycloid;

The short cycloid and the needle teeth satisfy the tooth profile engagement law;

Compared with the theory of gear conjugate meshing transmission such as involute gear, the theory has the following problems:

(I) Lack of rigorous mathematical derivation, the problems of meshing equations, meshing lines, etc., which are closely related to the transmission characteristics, are not elaborated;

(II) The theory is not systematic, such as a tooth difference, multi-tooth difference planetary transmission is usually discussed separately, the unreacted internal gear tooth profile is determined as the essence of the conjugate tooth profile after the pin tooth;

(III) There are self-contradictory conclusions, such as continuous transmission condition, the needle wheel has one more tooth than the cycloidal wheel, but in fact the two-tooth difference and the three-tooth difference can fully mesh with the transmission;

(IV) The concept is not clear, and no clear definitions and calculation methods are given for correct meshing conditions, coincidence, etc.