Lubrication status of reducer gears

The reducer mainly includes the lubrication of gears and bearings, reducing the friction coefficient, thereby improving the service life of the equipment. The mechanical equipment only needs to have a moving pair to have relative motion. The lubrication condition of the tooth surface is related to the contact stress, sliding speed and direction of the tooth surface. Lubricating oil functions are closely related. In addition to working hard on the material of the equipment, according to the theory of elastohydrodynamic lubrication, because the gear transmission is characterized by a very short meshing time and simultaneous sliding and rolling, and the sliding direction and size are changing rapidly, the touch area is very small and The touch stress is very high, and the original pressure-bonding connection has failed under high pressure (high stress). In this case, according to the test results, the smoothness of the gear can be divided into three types:

1. Complete full oil film lubrication. The tooth surface is completely separated by the elastic hydrodynamic oil film, the friction on the outer surface of the gear teeth is transformed into the intermolecular friction inside the oil film, and the friction coefficient is very small. The thickness of the oil film is not greatly affected by the load, and the load is entirely borne by the oil film, and the probability of pitting, gluing, wear and other damage is very small, which is an ideal situation.

2. Smooth borders. The thickness of the elastic-hydrodynamic lubricating oil film is less than the comprehensive roughness of the two tooth surfaces. There is no flowing oil film between the gear teeth (the high-speed gear is outside), and the tooth surfaces can only be separated by the boundary oil film. It is prone to abrasion, adhesion and gluing. In order to prevent the direct contact of the tooth surface, an oily agent and an extrusion agent should be added to the base oil to improve the function of the lubricating oil and form an adsorption film and an extrusion lubricating film. Boundary lubrication is an unstable lubrication condition.

3. Mixed lubrication condition. It is between the first two. There are both elastohydrodynamic lubrication and boundary lubrication between the tooth surfaces. The lubrication conditions are very different. Some are close to elastohydrodynamic lubrication, and some are close to boundary lubrication.