In order to guarantee the normal operation and use of the double gear effectively and facilitate material processing, the height tolerance of movement dimensions, position height tolerance and surface roughness of gear main components must meet certain process standards at the same time.
1. Operating method for original machining of double gear
All double gear shafts can be machined on a horizontal sliding gear hobbing machine, i.e. rough sliding gear hobbing – half-refining rolling gear making – half-refining gear hobbing.After careful statistics, it is found that the working hours of heavy and large gear hobbing equipment account for about half of all large gear making equipment.Because the precision requirement of rough-shaft flat-roller gear machine is relatively low, and the precision requirement of semi-finish and fine hobbing is too high to be replaced, it is decided to divert the rough hobbing.After careful analysis, it is decided to replace rough Hobbing with finger milling cutter on single-pillar milling machine.
2. Improved Processing Methods
The improved tooth-making sequence is roughing-semi-finishing hobbing-finishing hobbing.In order to effectively guarantee the smooth implementation of single-pillar milling and rough milling of teeth, a simple tooling has been designed and manufactured.
Rough milling process:
(1) Workpiece clamping and positioning.The two shaft segments of the double gear shaft are machined to the same size and are solid with V-shaped iron pads at the two shaft segments with the same diameter.
(2) Workpiece correction.Axial 90 two-way strong pull gauge with allowance of 0.05m guarantees that the rotating axis runs parallel to the table, spindle and material box of the driving workpiece in horizontal direction. The driving workpiece is compressed with a strong press plate.
(3) Dimensional depth micrometer method.Measuring the distance from the outer circle of the workpiece dividing dial to the outer diameter of each workpiece (shaft circumference and shaft head of double-axle single-coupling toothed shaft impeller) shall be the basic standard, ensuring that the inner and outer circumferences of each workpiece are equal, and that the workpiece dimension depth at the dial is equal, then it can be shown that the workpiece indexing disc is coaxial with the shaft head of double-coupling gear.Finally, fix the circular division dial with four fixing bolts.
(4) Leveling should be based on indexing.Firstly, insert two cylinders and pins with equal circle diameter into the centre hole of the two indexing instrument panel and one hole at the circumference of the two equal lines, then place the inside of the two flat rulers flat on the pins between the two cylinders, correct the angle of the puller to 0-0 with the percentage, and the inside of the flat ruler is in a horizontal and vertical state. The milling of the first small serration can be started with two-hand finger milling cutter.
(5) Apply the indexing calculation method.After the first milling gear is finished, remove the flat ruler pin, rotate the whole work piece clockwise (or counterclockwise) repeatedly (dividing dial rotates repeatedly with other work pieces), put the processing pin into the second machining hole of two equal elliptical holes, put the hole on the flat ruler again, after leveling, start milling the second machining teeth, and so on.Till all toothing and moulding are finished.
(6) Analysis of indexing error.After comprehensive analysis of various machining errors, through detailed statistical analysis, it can be concluded that the main factor affecting the circular indexing error is only the circular indexing error of pin hole which is the most important.