JPS6130319A - Method of processing helical gear on numerical-controlled hobbing machine - Google Patents

Abstract

PURPOSE:To prevent the fall in accuracy of processing and the damage to a hob from being caused due to a phase discrepancy, by turning a helical gear depending on its lead and the quantity of movement of the hob in the direction of the axis of gyration of the gear to make the hob and the gear coincident with each other in phase. CONSTITUTION:The relation between the quantity Z of movement of a hob in the axial direction of a helical gear 11 and the rotation angle C of a table is previously determined in the form of C=(360/Q).Z.(1/ta) for each workpiece 11, where Q denotes the number of teeth of the workpiece and ta denotes the axial pitch of the hob, to immediately calculate the rotation angle C in terms of the quantity Z when the hob is moved in the axial direction of each workpiece. The determined relation is previously entered as phase adjustment information Gdd into a numerical controller. The information Gdd is used in processing the helical gear 11, to automatically turn the shaft of the table by the angle C calculated from the number Q of teeth of the workpiece 11, the axial pitch ta and the quantity Z of axial movement of the hob to make the hob and the helical gear coincide with each other in phase. A phase discrepancy is thus eliminated to prevent the fall in accuracy of processing and the damage to the hob.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cutting V-helical gears on a numerically controlled hobbing machine.

Generally, when gear cutting is performed on a helical gear using a numerically controlled (NC) hobbing machine, cutting is performed twice as shown in Figures 1 to 3. is not particularly controlled. In other words, as shown in Fig. 1, rough machining v is performed using climb cutting and then finishing machining W is performed using the same climb cutting, or as shown in Fig. 2, rough machining V is performed on a part and the dimensions of that part are 1 of cutter 01' when performing processing W on the needle side and then finishing.
Since there is a difference △H between the first cutting height and the second cutting height, the difference △S in the rotational force direction of the workpieces 02 and 03 corresponding to this △H is the difference △S between the cutter O1 and the workpieces 02 and 113. There was a phase difference of . Further, as shown in FIG. 3, a phase difference also occurred during the second cutting of workpiece 04, which was cut by jumping a part of the workpiece.

This is because in NC hobbing machines, unlike mechanical hobbing machines, the cutter's one-way feed of the workpiece (A: #-nyaru feed) and the rotational force direction feed of the work table shaft are not connected by a gear train. This occurs because each axis is independently controlled, but this phase difference is not particularly corrected because programming is difficult and small differences are difficult to notice. However, the phase difference between the cutter O1 and the works 02, 03, and 04 not only adversely affects the machining accuracy, but also causes damage to the cutter 01 if the phase difference becomes too large. For this reason, with the recent spread of NC hobbing machines, there is an increasing demand for eliminating the phase difference between the cutter and the workpiece.

The present invention has been made in response to the above-mentioned demands, and is a helical gear in an NC hobbing machine in which the phase of the hob 1 and the tooth groove of the helical gear always matches when the hob is sent in the axial direction of the helical gear. 1. The gist of the present invention is to provide a processing method for processing a helical gear having a tooth profile created in advance by NC.
A method of machining with a hobbing machine, in which when the hob of the NC hobbing machine is sent in the direction of the rotation axis of the helical gear, the helical gear is moved to the lead of the helical gear according to the amount of movement of the hob. The present invention is based on a helical gear machining force method using an NC hobbing machine in which the helical gear and the hob are rotated accordingly to achieve phase alignment between the helical gear and the hob.

An embodiment of the present invention will be specifically described below with reference to the drawings.

FIG. 4 shows an explanatory diagram embodying an embodiment of the present invention. As shown in the figure, the following gear pitch ta (t, = distribution rnn: normal module) in the helical gear 11,
Number of workpiece teeth Q, axial movement tz, axial movement f
The following equation holds between table rotation angle C and lZK.

Therefore, by determining the relationship of equation (2) for each workpiece, when the hob cutter is sent in the direction of the axle force, the amount of movement 2
The work table rotation angle C can be determined relative to the rotation angle C of the work table. As the function Gdd for this formula (2) gold phase matching, NC
If you input it into the device, you can program the phase matching feed of the workpiece and hob cutter, GddGOOZziC±...
・(3), where Gdd:t! Helical gear phasing function, Goo: Rapid traverse positioning function, zzi: Z-axis command travel amount 2 mm, C±: Sign of helix angle and zi value of hoscutter and K
Determine the direction of the rotational force + and - of the table.

In addition, the general 2-axis positioning method is the same as before. This is GQQ Zzi.

When the phase matching function Gdd of the above-mentioned formula 7'j (3) is called, the Cheagle rotation angle C(,
The cheagle shaft automatically rotates by 1 degree) to bring the cutter and helical gear 11 into phase. In addition, if the helical gear 11 is not actually machined and the formula (3) is executed with idle feeding, it becomes possible to measure the lead error of the helical gear 11.

Note: In the casting example, the number of work teeth is Q5, and the axial pitch is t.
&s Aki7 The relational expression for calculating the rotation angle Ct based on the amount of movement 2 is input to the NC device using the phase matching function Gdd and L7, and the calculation process is automatically performed. It is also possible to input the customary information @ in N(l positions) and perform calculation processing each time.

As specifically explained based on the above embodiment, according to the present invention, when the hob is sent in the direction of the axial force of the helical gear, the phase between the hob and the tooth groove of the helical gear is correct under normal pressure. Since they match, there is no reduction in machining accuracy due to phase shift, and damage to the hob cutter can be prevented.

[Brief explanation of drawings]

Figures 1 to 3 explain the two-step cutting process for helical gears.
FIG. 1 is an explanatory diagram of two-time climb cutting, FIG. 2 is an explanatory diagram of -s two-time cutting, FIG. 3 is an explanatory diagram of two-time jump feed cutting, and FIG. 4 is an explanatory diagram of one implementation of the present invention. It is an explanatory diagram embodying an example. In the drawing, 11 is a cogwheel. Q is the number of teeth on the workpiece, 1 is the axial pitch, 2 is the axial travel amount, and C is the table rotation angle. Patent applicant: Mitsubishi Heavy Industries, Ltd. Sub-agent Patent attorney: Shibu Mitsuishi (and 1 other person) Figure 1 Figure 2

Claims (1)

[Claims] A method of machining a helical gear on which a tooth profile has been created in advance using an NC hobbing machine, wherein when the hob of the NC hobbing machine is sent in the direction of the rotational axis of the helical gear, the hob is machined according to the amount of movement of the hob. A method for machining a helical gear in an NC hobbing machine, characterized in that the helical gear is rotated according to the lead of the helical gear to achieve phase alignment between the helical gear and the hob.