JP2000280119A - Gear grinding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a pitch error defect and enhance grinding efficiency, by changing the cross-feed amount of a grinding wheel according to a CNC control program without dressing during one-round-processing of a gear. SOLUTION: This gear grinding method grinds a tooth flank on one side of a gear by cross-feeding a gear-to-be-ground to a grinding wheel in its rotational direction while the gear-to-be-ground is subjected to indexing rotation tooth by tooth, wherein the tooth flanks are ground by increasing the cross-feed amount gradually at a designated rate up to the designated number of teeth from the tooth flank at the start of grinding during one-round indexing rotation of the gear-to-be-ground. After one-round-processing of the gear, only the designated extra number of tooth are subjected to further grinding processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear grinding method, and more particularly, to a method of indexing and rotating a gear to be ground, and providing a notch by rotating the gear to be ground in a rotational direction with respect to a forming grinding wheel by CNC control. The present invention relates to a control gear forming grinding method.

[0002]

2. Description of the Related Art In forming and grinding a gear to be ground,
Normally, the tooth grooves of one tooth are ground using a forming grindstone that matches the tooth grooves of the gear, and the adjacent tooth grooves are sequentially ground while rotating the gear one tooth at a time. FIG. 2 illustrates gear grinding by a conventional grinding wheel, in which a grinding work surface (grinding wheel outer peripheral portion) of the grinding wheel 2 is trued in a shape corresponding to the tooth groove 1a of the gear 1 to be ground. While the gear 1 is stationary, the grinding wheel 2 is rotated around the axis A and cuts and fed in a direction perpendicular to the axis A (toward the tooth space), and the grinding wheel 2 is moved along the tooth trace of the gear 1. Then, after grinding one tooth, the grinding wheel 2 is separated from the gear 1 and then the gear 1 is indexed and rotated to grind the next tooth groove 1a.

In the above-described forming gear grinding, a pitch error defect is caused by abrasion of a grinding wheel, thermal displacement of a grinding wheel shaft, and the like. In this method, the grinding surface of the grinding wheel is modified once (dressing) once, and then the remaining number of teeth is ground again.

[0004]

Generally, dressing of a grindstone is performed so that a worn or clogged portion of the grindstone is trimmed to generate a new abrasive grain surface, and the grinding work surface of the grindstone is restored to its original shape. However, in actual grinding, immediately after dressing of the grindstone, the abrasion of the grindstone is large, and accuracy is likely to be partially reduced. In addition, the accuracy of the grinding wheel is also deteriorated immediately before dressing because the abrasion of the grinding wheel is progressing. In the conventional method of adding dressing in the middle of one round machining by indexing and grinding of gears, the pitch error is poor before and after dressing. There was a problem that the size became large. In addition, performing treshing on the way increases the grinding cycle time per piece, which causes a problem that the working efficiency is reduced.

[0005] The present invention eliminates the above-mentioned conventional disadvantages,
Provided is a gear forming and grinding method that improves a pitch error defect and simultaneously improves a grinding operation efficiency by changing a cutting amount of a grinding wheel in accordance with a CNC control program without performing dressing in the middle of one round processing of a gear. It is in.

[0006]

According to the present invention, while the gear to be ground is indexed and rotated one tooth at a time, the gear to be ground is cut and fed in the rotational direction with respect to the forming grinding wheel so that one tooth of the gear is rotated. In the gear forming grinding method of grinding a surface, the grinding wheel cutting amount during rotating the gear to be ground one rotation,
Grinding the tooth surface by gradually increasing at a specified ratio from the tooth surface at the start of grinding to the specified number of teeth, and after one round processing of the gear,
Further, there is provided a gear forming grinding method in which grinding is performed by a specified number of extra teeth.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described with reference to the drawings. FIGS. 1A and 1B are schematic views showing a state in which a grinding wheel 2 performs a gear finish grinding when the grinding method of the present invention is carried out. In this embodiment, at the time of rough grinding, the entire tooth surface of one tooth groove is ground for each gear index for one tooth using the grinding wheel 2 formed for rough grinding by the conventional method shown in FIG. I do. In the finish grinding, the width of the outer peripheral portion of the grinding wheel, which is the grinding work surface of the grinding wheel 2, is formed to be slightly smaller than the groove width of the tooth groove, and the grinding work surface on one side matches the tooth surface on one side of the tooth groove. Molded.

Using such a grinding wheel 2, the grinding wheel 2 is inserted into one tooth groove 1a of the gear 1 while rotating the grinding wheel 2 around the axis A from the axial direction of the gear 1 to be ground. One tooth surface 1b to be ground of one tooth groove as shown in FIG.
The gear 1 is rotated so that is ground by the grinding wheel 2 (FIG. 1).
(A) rotate in the direction of the arrow) to give a cutting feed, and finish grinding one tooth surface 1b for one tooth. Thereafter, the grinding wheel 2 is moved in the gear axis direction to separate the grinding wheel 2 from the gear 1, and the gear 1 is moved in the opposite direction so that the other tooth surface 1 c belonging to the same tooth space as above is ground by the grinding wheel 2. Rotation (Fig. 1 (b)
(Rotation in the direction of the arrow) to feed the cut, the grinding wheel 2 is inserted into the tooth space from the gear axis direction, and the opposite tooth surface 1c of the same tooth space is finish-ground. Then grinding wheel 2
Is moved in the direction of the gear axis to separate the grinding wheel 2 from the gear 1, the gear 1 is divided into one tooth and rotated, and the tooth surfaces of the next tooth grooves are finished and ground one by one in the same manner as described above. Grinding is performed sequentially and repeatedly.

Here, in the present invention, instead of grinding the tooth surface of the entire circumference of the gear with the same depth of cut, the depth of cut during grinding the gear once is specified from the first tooth to the specified number of teeth. Gradually increase the ratio, then grind the remaining number of teeth with a constant depth of cut, and after one round machining, continue grinding with the number of extra teeth specified. The setting of the number of teeth to be specified, the rate of increase in the amount of cutting, the amount of cutting relative to the number of remaining teeth after the specified number of teeth, and the number of teeth that continue to be ground in four quarters after one round of grinding, etc. C in advance in consideration of displacement, etc.
Set in the NC control program.

FIG. 3 shows that the finish grinding of one tooth flank of a gear having 18 teeth is sequentially increased by setting the designated number of teeth to 5, that is, from the first tooth to the fifth tooth at a rate of 0.8 μm per tooth. FIG. 7 is a diagram showing the grinding wheel cutting amount (μm) for each tooth when grinding is repeated and grinding is continued for up to five more teeth after one round of grinding. The cut amount of the one side flank of the first tooth is 6.0 μm as shown in FIG.
Grind at a constant depth of cut of
This is an example in which the tooth from the tooth to the fifth tooth is ground at the same 10 μm. The other side of the tooth space was ground in the same manner as described above. Here, the first tooth is ground immediately after the dressing of the grinding wheel, and the depth of cut is made smaller than that of the other teeth in consideration of the wear of the grinding wheel immediately after the dressing. The extra grinding up to five teeth after one round of machining is for removing the uncut residue after the start of grinding.

FIGS. 4 (a) and 4 (b) are diagrams showing pitch error measurement results obtained by a conventional grinding method when the cutting amount of finish grinding is constant over the entire circumference of the gear.
(A) and (b) are pitch error measurement results when the tooth surface of a gear is ground by the grinding method of the present invention. FIGS. 4 and 5A show one tooth surface in the same direction for each tooth space,
(B) is a pitch error for the other tooth surface. FIG.
5 (a) and 5 (b) show a module 4 and a gear with 17 teeth and a constant cutting depth of 7 μm. FIGS. 5 (a) and 5 (b) show the same module 4 and a gear with 17 teeth and the cutting depth. The number of designated teeth was gradually increased to five, and the cutting depth of the first tooth was gradually increased from 7 μm to the cutting depth of the fifth tooth of 10 μm. The number of extra grinding teeth after one round of grinding was set to five, and the five teeth were ground at the same cutting depth of 10 μm.

In the conventional method shown in FIG. 4, a large pitch error is observed on one side of the tooth surface (FIG. 4B).
In the case of the present invention, the pitch error range is limited to a maximum of about 3 μm. In particular, the pitch error is hardly observed in the entire circumference of the gear in one tooth surface (FIG. 5B). The measurement was attached to a gear forming grinder that was ground in all cases,
It was measured on the grinder.

[0013]

As described above, according to the present invention, in the tooth groove grinding of the gear, the cutting amount of the grinding wheel is reduced immediately after the dressing, and the first grinding after the dressing is performed.
Grinding by gradually increasing the depth of cut from the teeth to the specified number of teeth, and continuing to grind the tooth surface to an extra specified number of teeth after one round of grinding, the pitch error has been improved, and during one round of grinding Since the dressing is not performed, the effect of improving the efficiency of the grinding operation can be obtained. Since the setting of the designated number of teeth and the setting of the gradual increase of the depth of cut are also performed by the control program using the CNC gear grinding machine, the operation is easy.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a state during gear finish grinding by a forming grinding wheel when the grinding method of the present invention is carried out.

FIG. 2 is a view exemplifying gear grinding by a conventional forming wheel.

FIG. 3 is a diagram exemplifying a grinding wheel cutting amount (μm) for each tooth in the forming and grinding method according to the present invention.

FIG. 4 is a diagram showing pitch error measurement results obtained by a conventional grinding method when the depth of cut in finish grinding is constant over the entire circumference of the gear.

FIG. 5 shows a pitch error measurement result when gear tooth surface grinding is performed by the gear grinding method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Grinded gear 1a Tooth groove 1b, 1c Tooth surface 2 Grinding wheel

Claims (2)

[Claims] 1. A gear forming and grinding method for indexing and rotating a gear to be ground one tooth at a time and cutting and feeding the gear to be ground in a rotational direction with respect to a grinding wheel to grind a tooth surface on one side of the gear. Grinding the tooth surface by gradually increasing the grinding wheel cutting amount while rotating the gear to be ground one rotation from the tooth surface at the start of grinding to the specified number of teeth at a specified ratio,
A gear forming / grinding method, further comprising, after one round of processing of the gear, performing additional grinding by a specified number of teeth. 2. The gear forming grinding method according to claim 1, wherein the cutting feed of the gear to be ground is CNC-controlled, and the specified number of teeth and the specified increase rate are performed by a control program. .