Analysis of the Causes of Glue and Scratch on the Tooth Surface of Gear Reducer

- Jan 15, 2021-

Analysis of the reasons for gluing and scratching of the tooth surface of the gear reducer: the metal of the two meshing tooth surfaces of the gear is in direct contact under a certain pressure. After the "welding", there is relative movement, and the metal is torn from the tooth surface. Or transfer from one tooth to another tooth surface and cause damage. This is a more serious form of wear. It is locally bonded through the contact surface, and the bonding part separates under relative movement, causing small bits on the contact surface to be pulled out. This process is repeated many times and the tooth surface is damaged. Gluing and scuffing generally occur in heavy-duty or high-speed gear transmissions, mainly due to improper lubrication conditions that cause the oil film between the tooth surfaces to break.   

The macroscopic feature of cemented wear is that the tooth surface presents deep and wide strip-like rough grooves along the sliding speed direction, which are more serious at the tooth tip and tooth root, and the noise increases significantly at this time. Gluing is divided into cold bonding and thermal bonding. Cold bonding has clear grooves, and hot bonding may be accompanied by discoloration caused by high temperature burns. Cold bonding tears are formed under heavy load and low speed transmission. Due to the high local pressure, the oil film on the surface ruptures, causing direct contact with the metal surface of the gear teeth. When plastic deformation occurs under pressure, the contact points are bonded due to molecular diffusion and local recrystallization. When sliding, the joints are closed. It is torn to form a cold adhesive tear.    Thermal adhesive tears are usually formed in high-speed or heavy-duty medium-speed transmissions. Due to the local temperature rise at the contact points of the tooth surface, the oil film and other surface films are broken, and the surface metal is fused and then torn.   When the new gear is not run-in, it often produces glue in a certain part, causing the gear to scratch.