Gear machining process analysis

1, the choice of reference for the choice of gear machining benchmark often varies due to the structure of the gear shape. With shaft gear mainly adopts vertex hole positioning; For hollow shaft, then after the hole drilled in the center, with the slope of the orifice positioning; Large aperture cone wall is adopted. Vertex positioning precision, and can achieve benchmark superposition and unity. In perforated gear tooth surface processing and often in the following two kinds of positioning, clamping way. ( 1) Within the hole and face location hole within this way of positioning is based on the workpiece positioning, determine position position, axial positioning to end as a benchmark, and at the end clamp. That can make the locating datum, design benchmark and assembly benchmark and measurement datum coincidence, high positioning accuracy, suitable for mass production. But for fixture manufacturing precision is higher. ( 2) Outside circle and end face positioning when artifacts and spindle fit clearance is larger, and the external circular dial gauge calibration to determine the location of the center, and axial positioning, to face on the other end clamp. This way of positioning for each artifact correction, so the productivity is low; At the same time, to gear billet internal and external circular coaxial demand is high, and the accuracy of the fixture is not high, so it is suitable for single piece and small batch production. To sum up, in order to reduce the positioning error, improve the gear machining accuracy, when processing shall meet the following requirements: 1) Should choose the benchmark superposition, unified way of positioning; 2) Inner hole positioning, fit clearance should be nearly may reduce; 3) End face and positioning holes or cylindrical should be in a clamping processing, to ensure that the vertical degree requirements. 2, the gear tooth surface machining of blank in front of the gear blank processing, in the whole process of gear machining occupies very important position. Because the benchmark used in the tooth surface machining and testing must be out at this stage, gear blank processing at the same time, the proportion of working hours is larger, no matter from the productivity, and ensure the quality of gear machining, must attach importance to the processing of gear blank. In gear design technical requirements, if the rules to choose graduation circle of the tooth thickness thinning amount to determine the gear side clearance, should pay attention to the accuracy requirement of addendum circle, because the tooth thickness detection based on addendum circle measurement benchmark. Addendum circle precision is too low, will inevitably make the measurement of tooth thickness can not correctly reflect the size of the gear side clearance, so, in this process should pay attention to the following three questions: 1) When the addendum circle as the measuring datum, should strictly control the size precision of addendum circle; 2) Ensure that the positioning end face and positioning holes or cylindrical verticality between; 3) Improve the manufacturing precision of the gear wheel inner hole, reduce and fixture fitting clearance of spindle; 3, tooth and gear tooth profile machining is the key to the gear processing, the scheme of choice depends on many factors, such as equipment conditions, the gear precision grade, surface roughness, hardness, etc. Tooth profile processing scheme of commonly used in the existing explanation, here no longer. Gear tooth processing are round, pour point, chamfering and deburring. As shown in figure 9 - 13. After rounding, pour point of meshing gear when shift easily into the state, to reduce the impact phenomenon. Chamfering can remove the gear tooth sharp corners and burrs. Figure 9 - But with a finger milling cutter is to pour round tooth processing schematic drawing. Round, tell rotary cutter, and along the arc swing, after processing a tooth, workpiece going milling cutter, the indexing and fast approaching milling cutter machining a gear tooth. Gear tooth processing must be conducted before quenching, usually in roll ( Plug) Gear, gear shaving before gear tooth processing. 4, wheel processing in the process of heat treatment requirement in the process of gear machining process, heat treatment process of position arrangement is very important, it directly affect the mechanical properties and of gear cutting processability. General in the gear processing two kinds of heat treatment process, namely the blank heat treatment and heat treatment of tooth profile