Machining the production of spiral bevel gears is a precise and complex process. Spiral bevel gears play an important role in mechanical transmission, enabling power transmission between intersecting shafts, and are widely used in fields such as automotive rear axles and industrial reducers. The selection of materials is crucial in the production process. High quality alloy steel, such as 42CrMo, is usually selected to ensure the strength and wear resistance of gears. Rough manufacturing generally adopts forging or casting methods. Forging can improve the internal structure of materials and enhance the performance of gears; Casting is suitable for production with complex shapes and large batches.
Tooth profile machining is the core process, and common methods include:
Gear hobbing: Using a gear hobbing machine and a hob, the tooth shape is cut using the principle of generating.
Gear milling: Use a gear milling machine and specialized milling cutters for machining.
During tooth profile machining, it is necessary to accurately control the motion parameters of the machine tool and the installation position of the tool to ensure the accuracy of the tooth profile and the contact quality of the tooth surface. For example, in the machining of spiral bevel gears on the rear axle of automobiles, there are very strict requirements for contact spots and noise on the tooth surface, which require fine adjustment and testing to meet the standards.
In order to improve the hardness and wear resistance of gears, heat treatment is an essential step, commonly including carburization quenching, induction quenching, etc. Afterwards, precision machining processes such as gear grinding will be carried out to further improve the accuracy and surface quality of the tooth surface. In terms of quality inspection, professional testing instruments such as gear measurement centers are used to comprehensively test various parameters of gears, including tooth pitch error, tooth profile error, tooth orientation error, contact area, etc.
The accuracy and load-bearing capacity of spiral bevel gears used in industrial reducers directly affect the performance and service life of the reducer. Therefore, in the machining production process, every step needs to be strictly controlled to ensure the production of high-quality spiral bevel gears.
CNC turning is not the preferred method for producing gears, as the tooth profile of gears is often complex and difficult to accurately machine through turning. However, in some cases, especially when the tooth profile of the gear is relatively simple or only partial machining is required, CNC turning machines can be used for machining.
The following are the basic steps for producing gears using CNC turning:
Design:
Use CAD software to design the geometric shape of gears, including key parameters such as tooth number, modulus, pressure angle, etc.
If the tooth profile of the gear is relatively simple, the complete tooth profile can be designed directly in CAD software; If the tooth profile is complex, it may be necessary to first design the basic shape of the gear, and then use other machining methods (such as milling, grinding, etc.) to process the tooth profile.
Programming:
Convert CAD design into machining programs that can be recognized by CNC machine tools. This usually involves importing CAD files into CAM software and generating G or M codes.
In the programming process, it is necessary to define parameters such as cutting tool, cutting path, cutting speed, feed rate, etc. For gear machining, special attention should be paid to the setting of the cutting path to ensure that the tooth profile of the gear can be accurately machined.
Set up CNC turning machine:
Fix the selected material (usually cylindrical or block shaped) on the workbench of the CNC turning machine.
Install and adjust cutting tools (such as turning tools) according to the machining program.
Processing:
Start the CNC turning machine and start the machining process. The machine tool will automatically cut according to the machining program, gradually processing the material into the basic shape of the gear.
If the tooth profile of the gear is complex, other machining steps (such as milling, grinding, etc.) may be required after CNC turning to machine the tooth profile.
Post processing:
After processing, perform necessary post-treatment on the gears, such as removing burrs, heat treatment (such as carburizing to improve hardness and wear resistance), coating, etc.
Conduct quality inspection on gears, including size measurement, accuracy testing, surface quality inspection, etc., to ensure that they meet design requirements.