The research status of grinding surface integrity of spiral bevel gear is deeply analyzed. Firstly, the basic experimental research of surface grinding is carried out for the common material 30CrMnTi of spiral bevel gear, and the variation laws of grinding force, surface microstructure, microhardness and residual stress are obtained. Then, the grinding temperature field and surface residual stress of gear steel 30CrMnTi are obtained based on ANSYS simulation. Finally, the actual machining test of spiral bevel gear is carried out, and its grinding surface integrity is systematically and deeply studied. The main conclusions of this paper are as follows:
- The grinding force of gear steel 30CrMnTi in both directions decreases with the increase of grinding speed; With the increase of grinding depth or workpiece speed, the grinding force increases. The empirical formula of grinding force per unit width is obtained by multiple linear regression. The grinding temperature field of gear steel 30CrMnTi is obtained by ANSYS simulation. It is found that the maximum grinding surface temperature of gear steel 30crmnti increases with the increase of grinding speed and grinding depth, decreases slightly with the increase of workpiece speed, and the change of grinding depth has the greatest impact on grinding temperature.
- After grinding, the surface microstructure of gear steel 30CrMnTi is acicular martensite + carbide + a small amount of residual austenite, and the core microstructure is plate martensite + ferrite. The martensite structure of the strengthening layer is relatively uniform and shows a “fine coarse” change trend from the grinding surface to the core. The hardness in the strengthening layer increases first and then decreases with the increase of surface depth, The depth of strengthening layer becomes deeper with the increase of grinding depth or grinding speed. The surface hardening degree is between 2% and 13%, which increases with the decrease of grinding speed or the increase of grinding depth.
- Residual stress of gear steel 30CrMnTi grinding surface σ From the original stress of blank surface layer σ 0 and residual stress during grinding Δσ It is composed of two parts. The residual stress on the surface of the original workpiece is about – 225 MPa, and the maximum residual compressive stress is obtained at the depth of about 0.4 mm-0.5 mm, which is about – 360 MPa. Grinding will change the distribution of residual stress on the surface. After that, the residual stress in the grinding process will be Δσ Compared with the data obtained by ANSYS simulation, the results show that the simulation can reflect the change law of test results to a certain extent, and verify the effectiveness of the simulation model. Residual compressive stress on grinding surface σ Under the condition of dry grinding, it decreases gradually with the increase of grinding depth or grinding speed, and increases slightly with the increase of workpiece speed. Under the condition of wet grinding, the compressive stress caused by grinding force plays a leading role. With the increase of grinding depth, the value of residual compressive stress increases gradually.
- After the spiral bevel gear is processed under the given grinding conditions, the tooth surface has no obvious defects such as grinding cracks or grinding burns from the macro point of view. The value range of gear surface roughness is about 0.4 ~ 0.65, and the machined surface roughness decreases with the increase of grinding speed and increases with the increase of grinding depth and gear growth speed. After grinding, the tooth surface is in a state of compressive stress, and the compressive stress is concentrated between 300 MPa and 550 MPa. For the residual stress of the tooth surface under the same group of grinding conditions, the value of the residual compressive stress in the pitch area is greater than that in the tooth root area and tooth top area. Finally, the influence degree and power exponential empirical formula of various parameters on surface roughness and residual stress are obtained through orthogonal test, and the relative optimal control solution of surface roughness and residual stress AP = 33.6 is obtained by comprehensive balance method μ m. Vs = 21.7 M / s, w = 10.8 ° / s, RA = 0.4927 μ m, σ = – 414MPa。