In recent years, the electric vehicle and robot market has shown a rapid development trend. Gear is an important mechanical component in the above types of machines, and its machining technology has always been a hot research direction. At present, the commonly used gear cutting method is gear hobbing or gear shaping. For example, tianq et al. Developed a method to improve the cutting accuracy of hobbing gears. Zhao Ning and others analyzed the influence law of common gear shaping machining errors on gear surface accuracy. This method requires the use of special tools, such as gear hobbing cutter or gear shaper cutter, and can only process gears with predetermined modulus and pressure angle. In other words, when machining gears with different modulus or pressure angle, it is necessary to change the tool. Therefore, gear hobbing or gear shaping processing method is only suitable for mass production, not small batch production.
In recent years, for customized small batch production problems, such as the demand for a single gear set, forming tools are usually used for milling. For example, Chen Yongpeng and others proposed a spatial forming model for hobbing multi edge intermittent gears. In the forming tool, the shape of the gear cutting edge is an involute curve, but its shape is different due to the gear parameters (such as modulus, number of teeth and pressure angle), so it can only process the predetermined modulus, pressure angle and number of teeth. In addition, forming tools are expensive and difficult to design. When companies or laboratories need special types of gears for product testing, it is very difficult to quickly obtain the required tools at a reasonable cost. A feasible solution is to use a five axis machining center, whose gear machining path is generated by a special cam. This is probably the easiest way to produce a single gear. The tool used is usually a spherical end mill. However, for some small workshops or laboratories, this high-performance cam cannot be used. In order to solve these problems, a low-cost gear cutting method which can be used in 5-axis machining center and general milling machine at the same time is needed.
A new gear cutting method using conical end milling cutter is proposed. This method can process gears with various gear parameters with a single conical end mill. The experimental results show that: (1) the proposed method can be directly realized by 5-axis machining center, and most of the deviations are within 10 μ M, with high accuracy. (2) By connecting a special feed synchronization device, the proposed method can be realized by using a general milling machine, and the maximum error of the tooth profile is 0.05 mm compared with the conventional hobbing machine. Further reliability verification will be carried out on workpieces of other materials.
This method uses a conical end mill as a tool to move back and forth in the tooth width direction and feed alternately along the pitch tangent direction to realize gear cutting. It can realize gear machining of various parameters and specifications, including module, number of teeth and pressure angle. The feasibility and practicability of this method are verified by practical application tests on 5-axis machining center and general milling machine.