How to use a universal milling machine to process helical gears
Choose the right milling machineThe worktable of the universal milling machine, selected in addition to the horizontal, vertical and vertical movements, should also be rotated. This is because the milling of helical gears, the table must be turned with the spiral angle equal to the angle of beta machining. Secondly, it is necessary to check whether the end of the transverse feed screw of the universal milling machine is provided with the shaft diameter and the keyway which are matched with the hanging wheel, and the universal milling machine with such a structure can be used. This is because the movement of the transverse feed screw of the table will enter the indexing head through the gear wheel. Finally, choose the indexing head which is matched with the milling machine table. This is because sometimes the dividing head of the input shaft end is too short, or the screw shaft diameter out too long, the dividing head is fixed at one end of the table, hanging round gear can't in the system with each other, the drive cannot be input into the dividing head caused by milling to.
Accurate calculation of outer diameter of helical gearFor the helical gear blank, the calculation of the outside diameter should be based on the formula: dy=Zmt+ZmnType: dy - helical gear blank diameter; Z number of teeth; MT module; here we should pay special attention to, in the processing of the helical gear milling machine, milling cutter for helical gear gear modulus Mn; then the formula mt=mn/cos beta obtained end module MT, calculated by the formula, from which the helical gear blank diameter dy. Here is the helical angle of the helical gear.
In the formula, n indexing crank should be turned several times; number of teeth T workpiece need helical gear indexing is equal number processing; A is an integer, to represent the complete laps when indexing each crank should turn; B is a true score, said in turn crank end A ring after, should also be in a hole on the circle (the denominator number of holes on the circular hole should be equal to the true value of the fraction) the number of turning hole distance (i.e. true numerator). If the tooth value can not directly on the helical gear indexing method or simple indexing, which is obtained by the denominator fraction number is not equal to any round hole on the indexing plate when the hole (usually 15, 16, 17, 18, 19, 20, 21, 23, 27, 29, 31 33, 37, 39, 41, 43, 47, and 49) such as Z=51, it is necessary for the differential indexing method, then in milling machining the helical gear is difficult, should consider other processing methods. This is because the input shaft of the indexing head has been occupied, so that the output of the dividing head spindle can not be connected with the input shaft of the indexing head when differential indexing, and the differential compensation is generated.
Analysis of 1. teeth numberBefore processing decisions of helical gear milling machine, calculate and analyze the number of teeth should be first applied basic formula of the gear indexing to processing, to see whether their values meet the number of teeth or direct graduation requirements can use simple indexing tooth number calculation formula for dividing 12 and 24 (2 reference data 3, 4, 6, 8), and the number of teeth of the required number of simple indexing turned the indexing disc hole should be calculated by the formula should be able to complete indexing crank laps and the lack of a circle.N=40/T=A+B
