Steyr's penetrating shaft is an important transmission component on the bridge (as shown in the figure), which bears the role of transmitting the torque transmitted by the propeller shaft to the rear drive axle. Its quality directly affects the normal operation of the vehicle. The original structure of the spline on the input side is a rectangular spline. The machining process is as follows: rolling rectangular spline A - grinding outer circle C - knurled key D - hot after straightening C - grinding rectangular spline A. In 2007, the company tried to change the STR through-shaft splines to involute splines, and conducted a small batch of trial production. The processing method was as follows: hot pre-grinding circle B—rolling involute splines A——— Thermal pre-grinding cylindrical C - knurled key D - hot after straightening C - hot after the straightening B, spline connection to involute, eliminating the original rectangular spline form grinding crack phenomenon, but In order to heat, it is necessary to add a rounding process at the grinding station C. Moreover, because of the heat, it is necessary to satisfy the alignment accuracy at the A and C positions at the same time, causing great difficulties in processing, and the production efficiency is affected. Physical vapor deposition (PVD) is a physical gas phase reaction growth method. The deposition process is carried out under vacuum or low pressure gas discharge conditions, ie in a low temperature plasma. The material source of the coating is a solid material that, after "vaporization or sputtering," produces a new coating of solid material on the surface of the workpiece that is completely different from the properties of the substrate. PVD coating materials are mainly composed of TiN, TiCN, CrN, TiAlN, AlTiN, AlCrN, WC/C, DLC and diamond. Different application fields require different coating materials. The thickness of the coating is usually only a few microns and the hardness is 2 to 5 times that of steel. Oerlikon Balzers Coatings Co., Ltd. invented a coating technology that replaces titanium with chromium, and in 2004 launched a single-layer AlCrN coating under the trade name “Balinit Alcornaâ€. The high red hardness of the AlCrN coating allows it to maintain stable performance even under extremely high thermal loads. Application tests at high speed cutting and dry (or quasi-dry) cutting conditions demonstrate excellent performance, high hardness and resistance of the coating. Wearability allows the hardness of the machinable material to reach HRC70. Vacuum Belt Filter,Slurry Dewatering Vacuum Filter, Tailing Process Belt Filter, Leach Residue Belt Filter Quantum Conveying Systems Yangzhou Co.,Ltd. , https://www.fkconveyor.com
In order to ensure the seal of the entire bridge, it is necessary to ensure the total run-out of the oil seal after the flange flange and the through-shaft spline are assembled. Therefore, the jump of the involute external spline to the outer diameter of the bearing installation is particularly important. According to the actual situation of our plant equipment, the through-shaft hot roll forward involute splined bouncing process guarantee capability is 0.04. Due to the increased difficulty of heat treatment and straightening, in the case of mass production, the straightening process after heat treatment and quenching has a guaranteed capacity of 0.08, which cannot meet the product drawing requirement of 0.06. It often occurs that the integrated runout of the oil seal after flange and through shaft spline assembly is large. The oil spill problem.
Tool coating principle and feasibility analysis
According to the principle of metal cutting, in normal cutting, the wear of the tool mainly includes the following: wear of the flank; wear of the rake face, that is, wear of the crescent; wear of the front and rear flank.
Tool coating refers to coating a thin layer of refractory metal or non-metal compound with vapor deposition method on the surface of hard alloy or high speed steel (HSS) substrate with good strength and toughness. A chemical barrier and thermal barrier reduce the diffusion and chemical reaction between the tool and the workpiece, reducing crater wear. Coated tools have high surface hardness, good wear resistance, chemical stability, resistance to heat and oxidation, low friction factor, and low thermal conductivity. The figure shows the cutting conditions of coated and uncoated tools by Oerlikon Balzers. 
Uncoated and coated cutter cutting microscopic diagram left: Uncoated cutter, due to large friction coefficient and other reasons there is a serious built-up edge right: coated cutter, friction coefficient, no significant built-up edge
Through-shaft product material is 49CrMo4, heat treatment technology requirements are: induction hardened layer depth 5-7mm, surface hardness 50-55HRC, the heart is quenched and conditioned, hardness requirements 35-40HRC. It is theoretically possible to apply the coated tool to cut the heat through the shaft.
A spline hob was used to perform the process test after coating with Oerlikon Balzers. The process method is as follows: hot front grinding outer circle C—knurled key D—heated and then straightened at C—hot back knurled key B, and the original knurled key process is transferred to heat and processed.
With the original cutting parameters unchanged (S=250r/min F=13m/min), the processing noise is significantly reduced. The quality of processed products was tracked, and 10 random tapping shaft splines and M value fluctuations were randomly sampled. It can be seen from the recorded data that the application of coated tool heat after roll-cutting through the shaft accurately meets the drawing requirements. Accuracy requirements can be canceled. When the amount of variation in M ​​value is reduced, the amount of change in the backlash after assembly with the flange is increased, thereby improving assembly accuracy.