What Are The Advantages Of Gear Hobbing Machine

[Grayce Bird]

Gear hobbing machine is one of the most widely used gear processing machine tools. It can cut straight and helical cylindrical gears, as well as worm gears and sprockets. When using a special hob, this machine tool can also process various special tooth shaped workpieces such as splines and sprockets. It is widely used in automobile, tractor, machine tool, engineering machinery, mining machinery, metallurgical machinery, petroleum, instrument, aircraft and spacecraft and other machinery manufacturing industries. There are many kinds and specifications of gear processing machine tools, including small machine tools for processing gears with a diameter of several millimeters, large machine tools for processing gears with a diameter of more than ten meters, and high-precision machine tools for processing precision gears with high-efficiency machine tools for mass production. The following is a brief introduction to the characteristics of the lower gear hobbing machine:

first, the processing principle of the gear hobbing machine

according to the forming principle of the gear, comprehensively considering the requirements for the follow-up and rapidity of the mechanical feed system in hobbing and the transformation cost, and on the basis of retaining the gear splitting transmission chain of the original ordinary gear hobbing machine, according to the two coordinate circular arc interpolation principle in the numerical control theory, The vertical feed motion and horizontal radial feed of the tool holder of the machine tool are numerically controlled to realize gear machining
II. Transmission chain analysis of gear hobbing machine

gear hobbing machine shall have the following transmission chains: main motion transmission chain, generative motion transmission chain, vertical feed motion transmission chain, axial motion transmission chain and radial feed motion transmission chain
III. working motion of gear hobbing machine

(1) main motion: the main motion is the rotary motion of hob
(2) generating motion: for the rotation of hob and workpiece, the rotation of hob and workpiece is driven by servo motor respectively. The servo motor moves according to the control command to strictly ensure the synchronization of hob and workpiece. The scheme has large investment, high cost, high requirements for real-time control of motion controller, and it is difficult to program control software
(3) vertical feed motion: vertical feed motion means that the hob makes continuous feed motion along the axial direction of the workpiece to cut out the tooth profile on the whole tooth width. The axial feed is driven by servo motor, and the required feed speed can be obtained by adjusting the rotating speed
(4) radial feed: the workpiece makes radial feed to the hob direction, and the vertical feed movement and radial feed are linked to process the drum gear. The horizontal radial feed is driven by servo motor. The hob moves tangentially cnc machining parts supplier through worm pair and screw pair. The required tangential feed speed can be obtained by adjusting the speed of servo motor
4. The CNC system of the gear hobbing machine

uses the open motion control card to drive the motors of each axis, gives full play to the advantages of software and hardware on the CNC platform, and enriches and improves the development environment. The hardware circuit consists of peripherals, signal conversion circuit and auxiliary circuit to form a complete simple NC system, which completes a series of functions such as program input and processing, display, motor drive and so on
v. precautions for machining of gear hobbing machine

(1) when machining gears on NC gear hobbing machine, the position of each axis shall be determined according to the workpiece drawing parameters, fixture size, hob parameters and process requirements. The two coordinates shall be linked, and the circular arc interpolation method shall be used to process drum straight and helical gears symmetrical to the workpiece tooth width and with circular arc
(2) under the condition of meeting the needs of practical application, in order to reduce the cost and reduce the number of NC shafts as appropriate, there are few changes to the original mechanical gear hobbing machine. The drum gears of different sizes can be processed through parametric setting, and the operation is simple and convenient
(3) servo motors are used to control the feed shaft separately through the NC system. The feed system of the NC machine tool should meet the basic requirements of no gap, low friction, high stiffness and so on
(4) check whether the motion error of each axis exceeds the limit, servo alarm, motion completion, limit switch action, etc. The real-time control module is realized by the interrupt service program. It reads the position of each axis in each clock interrupt cycle, calculates a new motion control instruction according to the machining process requirements of the machining object, and sends it to the mover for interpretation and execution
(5) due to the high difficulty of gear processing, especially the processing of superhard workpieces such as stainless steel and titanium alloy, special gear cutting oil should be selected to ensure the accuracy of gear workpieces
the above are the advantages of using gear hobbing machine to process gears. For different gear workpieces, appropriate process methods should be selected according to the requirements of part drawing parameters and hob parameters.