Commonly usedSprocketsGear processing method
1.Forming method
This gear milling method is a forming method. In milling, the workpiece is mounted on the indexing head of the milling machine, and a disc (or finger) milling cutter of a certain modulus is used to mill the gear tooth intervals. When one interdental is machined, indexing is performed and the next interdental is milled. Features of gear milling: simple equipment; low tool cost; low productivity; low accuracy of machined gears.
The profile shape of a gear is determined by the size of the base circle (related to the number of teeth of the gear).
Milling gears by forming method requires simple movements and no special machine tools, but indexing with indexing head and low productivity. This method is generally used for single-piece small batch production of low precision gears.
2. Spreading method
When gears are machined by the spreading method, the involute of the gear surface is formed by the spreading method, which has higher productivity and machining accuracy. The majority of gear processing machines use the spreading method.
1）Hobbing
The principle of gear hobbing is to simulate the process of rolling a pair of staggered shaft helical gear pairs together. Reducing the number of teeth of one of the gears to one or a few, with a large helical inclination of the gear teeth, becomes a worm . Then the worm is slotted and spade back, it becomes a gear hob. When the machine tool makes the hob and the workpiece strictly according to a pair of helical cylindrical gear meshing ratio relationship for rotary motion, the hob can continuously cut out teeth in the workpiece.
Hobbing characteristics:
a. Good adaptability;
b. High productivity;
c. The surface roughness of the tooth profile after machining is greater than the surface roughness of the tooth profile processed by inserting teeth;
d. Mainly used for machining straight and helical cylindrical gears and worm wheels.
2) Inserting teeth
The gear shaper is used to process internal and external cylindrical gears, especially suitable for processing internal gears and multi-link gears, which cannot be processed by hobbing machines. With the attachment, the shaper can also process rack, but the shaper cannot process worm wheel.
3）Shaving teeth
Shaving is a process in which the shaving cutter drives the workpiece to rotate freely and simulates a pair of helical gears making a double-sided mesh without side clearance, with the shaving cutter intersecting the axis of the workpiece at an angle. Shaving is commonly used for finishing unhardened cylindrical gears with high productivity, and is one of the most common machining methods for soft tooth finishing.
4) Honing of teeth
Honing is a gear finishing method used to process hardened tooth surface, the relative motion between honing wheel and workpiece is the same as shaving, the difference is that the honing wheel as a cutting tool is a plastic gear cast or hot pressed with diamond abrasive and epoxy resin and other materials as a bonding agent.
5）Sharpening of teeth
The main features of gear grinding are: high machining accuracy, machining accuracy up to IT4～6 under general conditions, and not only strong ability to correct errors due to the forced meshing method, but also the ability to process gears with high surface hardness.