JPH0513463Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a shaving cutter for finishing gears having unequal pitches.

(Prior art) It is known that the effect of making the pitch of gears (including sprockets) unequal is one of the measures against gear noise, and in some fields (for example, the automobile industry), the use of such gears is is planned.

(Problem to be solved by the invention) However, conventionally, in order to manufacture gears with unequal pitches as described above, the gears were machined using a pinion cutter with unequal pitches, or a work piece cut with gears at equal pitches was used. It was then polished to an unequal pitch by grinding.

By the way, the conventional shaving cutter is
As shown in Figures 6 to 6, a large number of teeth 2 are provided at equal pitches on the outer periphery of a disc-shaped main body 1, and each tooth 2 is provided with a large number of serration cutting edges 3. The teeth 2 were formed so that the number of teeth was not divisible by the number of teeth on the workpiece so as not to hit a spot twice. Therefore, if shaving is performed on a workpiece that has been cut with a pinion cutter with unequal pitches, the pitches will become equal again, making it impossible to create gears with unequal pitches by shaving. was. For this reason, when attempting to create unequal pitch using a pinion cutter, it is necessary to stop at the processing stage using the pinion cutter and omit the shaving process, which limits the production of gears to JIS class 6 to 7 at most. There was a problem that I had no choice but to do.

In addition, when making the pitch unequal by tooth grinding, 1
It takes a long time (20 to 40 hours) to manufacture one gear because the pitch must be changed for each tooth.
There was a problem in that it required a lot of time and mass production was not possible.

The present invention was devised in view of the above-mentioned conventional problems, and its purpose is to provide a shaving cutter that can manufacture unequal pitch gears with high precision and high efficiency.

(Means for Solving the Problems) Therefore, the present invention provides a method for gears in which the teeth corresponding to the regular tooth grooves are missing, and the total number of teeth and the number of missing teeth is cut at an equal pitch. The number of teeth is the same as the number of teeth of the workpiece, or an integral multiple thereof.

(Function) In the shaving cutter configured as described above, since the tooth corresponding to the regular tooth groove is missing, the shaving process is performed exclusively by teeth other than the missing tooth, and the desired tooth surface is shaved. It becomes possible to include In addition, since the number of teeth is the same as the sum of the number of teeth on the workpiece and the number of missing teeth, or an integral multiple thereof, the same teeth will inevitably hit the same place on the workpiece, and therefore, the number of missing teeth on the cutter will The workpiece tooth surface corresponding to the tooth always remains unprocessed, resulting in unequal pitches.

(Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings.

FIG. 1 shows an example of the shape of an unequal pitch gear that is finished by a shaving cutter according to the present invention. This gear A has teeth (tooth number') in which both the L and R surfaces are formed as regular tooth surfaces, and either the L or R surface is ground down by a predetermined depth l from the regular tooth surface. teeth (tooth numbers ′, ′, ′, ′, ′, ′), and teeth with both L and R surfaces ground down by a predetermined depth l from the normal tooth surface (tooth numbers ′, ′, ′). It consists of a combination of In other words, this gear A has both a tooth space with a regular width and a tooth space that is wider than the regular width.

In this case, if the R surface of the 'tooth is taken as a reference, the pitch between the 'tooth and 'tooth will be reduced by the cut-off amount l from the regular pitch, and the pitch between the 'tooth and 'tooth will be the regular pitch, and further, ' The pitch between the teeth is a value that is greater than the normal pitch by the cut-off amount l, and in the end, when the cumulative pitch error of each tooth is taken, the specific tooth shifts to the negative side as shown in Figure 2. A unique pattern can be obtained.

As shown in FIG. 3, the shaving cutter for finishing the gear A having the above shape has teeth 12 provided on the outer periphery of the main body 11 partially missing. More specifically, the tooth 12 corresponding to the regular tooth groove of the gear A, that is, the tooth groove between the 'tooth and' tooth, the 'tooth and' tooth, the 'tooth and' tooth, and the tooth groove between 'tooth' and 'tooth'. Corresponding tooth number,,
, the teeth 12 are completely missing.

On the other hand, the total number of teeth 12 and the number of missing teeth of this shaving cutter is set to an integral multiple (in this case, three times) of the gear A.

With such a configuration, when this shaving cutter is engaged with a workpiece whose teeth have been cut at equal pitches in advance, the chipped teeth 12 do not come into contact with the tooth surface of the workpiece at all, so machining is performed exclusively. Normally shaped tooth 1
2. However, the tooth 1
Since the sum of the number 2 and the number of missing teeth is an integral multiple of the number of teeth on the workpiece, even when the workpiece rotates, the same tooth 12 engages with the same tooth surface of the workpiece, and as a result,
Gear A with unequal pitch as shown in Figure 1
will be completed.

In the above embodiments, a workpiece that has already been gear-cut is used, but instead of this, a workpiece that has been machined with a shaving cutter having evenly pitched teeth after gear-cutting can be used. In this case, the tooth surface accuracy will improve further.

(Effects of the invention) As explained above in detail, the present invention makes the teeth corresponding to the normal tooth grooves missing, and the total number of teeth and the number of missing teeth is equal to or equal to the number of teeth of the workpiece. Since it is an integer multiple, it is possible to finish gears with unequal pitches by simply engaging a workpiece that has been cut with equal pitches, which significantly improves gear productivity and gear accuracy. was gotten.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an example of the shape of a gear that is the object of processing with the special pattern shaving cutter according to the present invention, Fig. 2 is a graph showing the cumulative pitch error of the gear, and Fig. 3 is a graph showing the shape of the gear. A plan view showing an example of the shape of the Schiebig cutter according to the invention. Figures 4 to 6 show the shape of a conventional Schiebig cutter, with Figure 4 being a plan view, Figure 5 being a perspective view, and Figure 6 being a top view. The figure is a partial sectional view. 11...Main body, 12...Teeth.

Claims (1)

[Scope of utility model registration request] The tooth corresponding to the regular tooth groove of the gear is missing, and the total number of teeth and the number of missing teeth is the same as or an integral multiple of the number of teeth of the workpiece cut at an even pitch. Special pattern shaving cutlet.