08
2022
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09
Gear Processing Technology: Selection of Gear Processing Reference
Author:
The gear processing technology often varies in the selection of processing references due to the different structural shapes of gears. For shaft gears, positioning is mainly done using the vertex hole; for hollow shafts, after drilling the central inner hole, positioning is done using the inclined surfaces of the holes at both ends; when the hole diameter is large, a cone plug is used. Vertex positioning has high precision and can achieve reference coincidence and unification. For hole gears, the following two positioning and clamping methods are commonly used during tooth surface processing. 1. Positioning by inner hole and end face This positioning method uses the inner hole of the workpiece to determine the positioning location, and the end face serves as the axial positioning reference, with clamping against the end face. This allows the positioning reference, design reference, assembly reference, and measurement reference to coincide, resulting in high positioning accuracy, making it suitable for mass production. However, it requires high manufacturing precision for the fixture. 2. Positioning by outer circle and end face When the fit clearance between the workpiece and the machining center shaft is relatively large, a dial gauge is used to correct the outer circle to determine the center position, and the end face is used for axial positioning, with clamping from the other end face. This positioning method requires calibration for each workpiece, resulting in lower productivity; at the same time, it has high requirements for the coaxiality of the inner and outer circles of the gear blank, while the precision requirements for the fixture are not high, making it suitable for single-piece and small batch production.
The gear processing technology often varies in the selection of processing references due to the different structural shapes of gears. Shaft gears mainly use vertex hole positioning; for hollow shafts, after drilling the central hole, positioning is done using the inclined surfaces of the holes at both ends; when the hole diameter is large, a conical plug is used. Vertex positioning has high precision and can achieve reference coincidence and unification. For hole gears, the following two positioning and clamping methods are often used during tooth surface processing.
1. Positioning by inner hole and end face
This positioning method uses the inner hole of the workpiece for positioning, determining the positioning location, and then uses the end face as the axial positioning reference, clamping against the end face. This allows the positioning reference, design reference, assembly reference, and measurement reference to coincide, resulting in high positioning accuracy, suitable for mass production. However, it requires high precision in the manufacturing of the fixture.
2. Positioning by outer circle and end face
When the fit clearance between the workpiece and the spindle is large, a dial gauge is used to correct the outer circle to determine the center position, and the end face is used for axial positioning, clamping from the other end face. This positioning method requires each workpiece to be calibrated, resulting in low productivity; at the same time, it has high requirements for the coaxiality of the inner and outer circles of the gear blank, while the precision requirements for the fixture are not high, making it suitable for single-piece and small batch production.
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