Effect of nozzle arrangement on heat dissipation performance and mechanical efficiency loss of bionic texture gear

Abstract Friction and wear are key issues in gear meshing. Lubrication, therefore, is used to reduce heat. The position and direction of the flow of the lubrication determined by the way the nozzles are injecting the fluid and by the texture on the flanks of the teeth, both have an influence on the heat transfer. Furthermore, the geometric characteristics of the tooth texture influences the friction behaviour directly. This article presents investigations on the impact of the tooth texture on wear. A proposal to prepare the tooth flanks with arc shaped grooves is made presenting the manufacturing process. Different measurements to determine the tooth flank texture and the friction are performed. Measurements showed that the arc groove gear had lower friction coefficients, wear depth, surface roughness Ra, and maximum tooth profile peak height Rq compared to conventional gears. The dynamic process of gear meshing is simulated by FEM analysis to understand the physics of heat flow and friction in detail, which revealed that the arc groove gear had reduced sliding distance, contact pressure, and wear depth, along with a higher convective heat transfer coefficient. Based on the measurement results of orthogonal test, two different nozzle arrangements are predicted: one is linear regression prediction (nozzle arrangement (A), and the other is nonlinear particle swarm optimization neural network prediction (nozzle arrangement (B). By measuring the torque loss value under the two nozzle arrangement conditions, it is found that the nozzle arrangement B is the best arrangement. The specific parameters are: injection distance is 56.0674 mm, injection angle is 8.4527°, nozzle diameter is 3.3955 mm, and pinion speed is 3000 r min⁻¹. Under this condition, the mechanical efficiency loss is reduced by 94.48%.