JPS624511A - Gear cutting method - Google Patents

Abstract

PURPOSE:To generate a spherical gear with no necessity for using a particular hob, by simultaneously controlling a longitudinal feed and a crossfeed to be combined for a hob and giving the feed to the hob fed along a circular arc locus. CONSTITUTION:A four-axis simultaneous control unit, combining feeds in directions X, Y, gives the feed in a corrected direction Fn to a hob 1. When a gear material W performs one rotation, the hob 1 rotates by the turn of a number of teeth to be generated. The feed in the direction X is synchronously given with the feed in the direction Y so that a gear cutting point is generated along a pitch line of meshing. Accordingly, a spherical gear can be generated with no necessity for using any particular hob only if an NC unit of general purpose type is provided.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method for cutting gears using a hob.

Figure 3 shows the most basic method of generating gear cutting using a conventional hobbing machine.
Shown below. This is done by rotating the hob 1, for example, in the C direction by applying it to the gear material W, which is a screw-shaped hob 1, and applying rotation in the b direction corresponding to the axial advance of the hob 1 to the gear material W. By applying longitudinal feed F in the axial direction, the gear G is subjected to generating gear cutting.

Here, since the hob 1 has a threaded shape, when cutting the spur gear, it is necessary to tilt the axis of the hob 1 by the helix angle of the hob 1. Also, when cutting helical gears, use hob 1.
The hob 1 is tilted by the sum or difference between the helix angle of the gear and the helix angle of the gear, and the hob 1 is installed so that the teeth of both gears match.

In this way, by giving the hob 1 a longitudinal feed R in the direction of the material's axis, a spur gear or a toothed gear can be created. A worm wheel can be created by giving the cutting feed (feed of cut).

Problems to be Solved by the Invention As described above, in the conventional generating gear cutting method using a hob, a so-called spherical gear is created in which the tooth profile is formed within a concentric spherical surface centered on a point on the rotation center of the gear. I can't.

The middle part of the present invention for solving the problems is to provide a method that enables generation gear cutting of so-called spherical gears using a hob. There is a method of gear cutting by simultaneously controlling the vertical feed of the hob and the horizontal feed of the hob, and giving vertical feed to the hob along an arc locus drawn around the point where the axis of the hob passes through the axis of the gear material. be.

This refers to the vertical feed of the hob, which is the relative feed relationship between the gear material and the hob in the axial direction of the gear material, and therefore the type of hob that moves and the type that moves the gear material! c! l
Any type that can be used is fine. In addition, the hob's horizontal feed (notch feed) is similar to Tsuta.

According to the present invention, a combined feed is created by simultaneously controlling the longitudinal feed 9 and the horizontal feed of the hob, and the hob is given feed along an arcuate locus. In other words, a feed is given as if to actively increase or decrease the amount of dislocation in the direction of the tooth profile to be created, and a so-called spherical gear is created.

Embodiment FIG. 1 is a diagram showing a more specific embodiment of the present invention, where l is a hob and a so-called spherical gear to be used to generate Gfl.

Let the meshing pitch circle Dp centering on the point O passing through the axis of the gear G, and let the gear specifications be the module m.
, number of teeth 2, pressure angle α, reference pitch circle diameter,
It is expressed as D0=m,Z.

The pitch circle diameter D2 of the gear center portion P2 is Dr” D,)+
2 xz.

It is m. X21''E dislocation system, with a positive dislocation relative to D.

Similarly, the pitch circle diameter D1 of the gear end P1 is D1=D,
-2Xl, m. It is an x mountain dislocation system number, and negative dislocations are set relative to Do.

Then, set the gear material Wl, which was previously formed into a spherical shape, on the work table of the hobbing machine, and
Process using conventional methods.

In this case, the rotation direction of the gear material W is the rotation direction 9C of the hob 1, the feeding direction of the hob 1 is Y which is parallel to the axis of the gear material W, and the feeding direction iX of the gear material W in the radial direction.
By combining the feed in the X direction (vertical feed) and the feed in the Y direction (tank feed) using a numerical control device for time control between four axes, corrected longitudinal feed in the F4 direction is given to the hob 1. In other words, F is applied to the hob 1 along an arcuate locus Q drawn with the axis of the hob 1 as the axis of the gear material W and a passing point 09 as the center.

Cut the teeth by giving the feed direction.

More specifically, when the gear material W rotates once, the hob 1 rotates by two times the number of teeth to be created.

Further, the feed in the Y direction is given at a speed sufficient to maintain tooth profile accuracy. At this time, the feed in the X direction is applied in synchronization with the feed in the Y direction so that the generating gear cutting point is along the engagement pitch line i.゛・The gear GH1 created in the above manner has a positive dislocation x2 in the center P2 of the gear, as described above, and a negative dislocation x1 in the same way at both ends P1 of the gear. be. Therefore, when looking at one tooth of the generated gear G, the tooth depth is the same at the center and both ends in the horizontal direction.

The tooth profile has a shape in which the tooth thickness and tip diameter change continuously. Figure 2 shows this change in tooth profile.
In the HH section of Figure 1, I! It becomes the tooth profile of Th in Fig. 2, and similarly 1. in Fig. 1. -I cross section and JJ cross section have tooth profiles of Tl and Tj in Fig. 2. However, Figure 2 is an exaggerated depiction.

Incidentally, since the normal pitch of a toothed gear with shifted gears is the same as that of a normal spur gear, no deviation occurs during meshing. Therefore, the spherical gear created as above is
It can be used as a gear transmission mechanism between input and output shafts where the shafts are not parallel. In this case, the other gear may be a spur gear.

Effects of the Invention According to the present invention, it is possible to provide a feed along an arcuate trajectory as a vertical feed of the hob using synthetic feed, and therefore, as long as there is a general-purpose NC device, a so-called spherical gear can be produced without using a special hob. Can be created.

[Brief explanation of the drawing]

FIG. 1 is an explanatory sectional view showing one embodiment of the present invention, FIG. 2 is a sectional view of the tooth profile of the gear shown in FIG. 1, and FIG. It is an explanatory diagram of the conventional hob gear cutting method. 1... Hob, G... Gear, W... Gear material, Q.
...Circular trajectory. m, tun yul Do...stem 'JIL'- the child's circle, z, life a Do = m
°Zba...α power ^ Dl...life 1-
h Go, Chimonin Xt-4pt4TL IIIIt, *
” ” ”-2°8゛°“X2-0. Salary 1 sentence
Dl...Yoshiki central sound Dobby r child circle I flea D2=Do+2-Xz-m

Claims (1)

[Claims] (1) Simultaneously control the rotational movement of the gear material, the rotational movement of the hob, the vertical feed of the hob, and the horizontal feed of the hob, and follow the circular trajectory drawn around the point where the axis of the hob passes through the axis of the gear material. A method for cutting gears, which is characterized by cutting gears by giving vertical feed to the hob.