JPS6336863B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flat die for rolling helical gears, oil grooves, etc., helical teeth or helical grooves by sandwiching the object to be rolled and moving it relative to each other. Alternatively, it relates to a flat die that is effective for forming grooves.

For example, as a method for manufacturing the helical gear 1 shown in Fig. 1, cutting with a hob cutter or the like or rolling may be considered, but the cutting method takes a long time and is difficult to cut due to the cutting edge of the hob cutter. Since incomplete parts are required, there are problems such as having to prepare a workpiece larger than the final product and also increasing tool costs. On the other hand, the rolling method does not cause the above problems, but because it applies a large load to the rolled object and causes it to plastically deform, the conventional methods do not have sufficient accuracy and are unavoidable. The reality is that the helical gear 1 is manufactured by cutting.

That is, when manufacturing the helical gear 1 by rolling, the object to be rolled 2 is sandwiched between a pair of flat dies 3 and 4 as shown in FIG. 2, and a load P is applied to each. This is carried out by moving the flat dies 3 and 4 in opposite directions to rotate the object 2 to be rolled. In particular, in the case of a helical gear 1 with an odd number of teeth, the distance between the object 2 and the flat dies 3 and 4 is Tooth trace errors occur because the number of meshing teeth changes. FIG. 3 is a diagram for explaining the movement of the meshing points, and when the rolled product 2 is at the position indicated by A with respect to the flat die 3, the two are at three points, a1 point, a2 point, and a3 point. When the rolled object 2 moves relatively to the position shown by B in Fig. 3, the two move to point b1,
They mesh at a total of four points, b2, b3, and b4, whereas the other flat die 4 and the rolled object 2 are opposite to the case shown in Fig. 3, and the rolled object 2 is shown by A. When in position B, they mesh at 4 points, and when in position B, they mesh at 3 points. When rolling a helical gear 1 with an odd number of teeth in this way, the number of meshing teeth and the meshing point change, and the meshing point position is different between one flat die 3 side and the other flat die 4 side. In order to
The amount of pushing into the object to be rolled 2 by the flat dies 3 and 4 changes. As a result, the load acting on the rolled object 2 changes and the rolled object 2 is displaced or deformed even slightly in the direction indicated by the arrow in FIG. 2, so the formed tooth trace 5 is shown in FIG. 4. As shown in FIG. Such an error e
This will not occur if the displacement or deformation of the rolled object 2 can be prevented, but in order to completely prevent the displacement or deformation of the rolled object 2, the rolled object 2 must be a rigid body. is actually impossible.

In this way, in the past, due to the large tooth trace error when rolling, it was not possible to obtain rolled products such as helical gears with a precision that could be used for practical purposes, and as a result, in many cases, rolling products were The reality is that they manufacture helical gears, etc.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a flat rolling die that can accurately roll helical gears, helical grooves, etc. The feature of this invention is that the tooth thickness of the biting tooth group, which is formed so that the tooth height increases sequentially, is thinner than the tooth thickness of the finishing tooth group that is formed following the biting tooth group. A series of finishing steps in which the face width of the biting teeth is set to be greater than or equal to the width of the teeth to be formed on the object to be rolled, and at least half of the number of finished teeth in the finished tooth group to be formed on the object to be rolled. The teeth are narrow finished teeth whose width that acts on the workpiece is narrower than the width of the teeth to be formed on the workpiece, and the end of the narrow finish tooth that starts meshing with the workpiece is It is located at a point set inward in the width direction from the meshing start end of the finished teeth or biting teeth. Therefore, in this invention, the phase of the waviness of the tooth trace that occurs due to changes in the number of meshing teeth and the meshing point is different between narrow width finished teeth and other finished teeth or biting teeth. Because the tooth is more aggressively embedded into the rolled object, the peaked areas are pushed in, making the entire tooth surface as smooth as possible and reducing errors.

Embodiments of the present invention will be described below with reference to FIGS. 5 to 15. In addition, in the examples described below, a pair of flat dies that sandwich the object to be rolled are as follows:
Since both have the same configuration, the configuration of only one flat die will be explained to avoid duplication of explanation.

5A and 5B are schematic diagrams showing one embodiment of the present invention, and the flat die 10 shown here has a base 1
The die is configured as a flat die for helical gear rolling with helical teeth 12 formed on the surface of the helical gear 1, and one end of the base 11 (the right end in FIGS. 5A and 5B) among these helical teeth 12. A plurality of helical teeth 12 in a predetermined range from 1 to 3 are set as a biting tooth group 13, a plurality of helical teeth 12 in a predetermined range following that are set as a finishing tooth group 14, and furthermore, a plurality of helical teeth 12 in a predetermined range from A plurality of helical teeth 12 in a predetermined range constitute a relief tooth group 15. That is, the biting tooth group 13 is made up of so-called biting teeth that gradually bite into the outer periphery of the cylindrical rolled object 2 to form so-called coarse teeth on the rolled object 2. The tooth height of the helical teeth 12 on the lower side is the lowest, and the tooth heights of the helical teeth 12 adjacent to the finished tooth group 14 are set to gradually become higher so that the tooth heights become approximately the normal tooth height. . In addition, the object to be rolled 2 in the biting tooth group 13
The face width L (indicated by the dimension in the width direction of the base body 11 in the figure) acting on the rolling material 2 is set to be larger than the face width W (indicated by the dimension in the axial direction in the figure) of the teeth to be formed on the object to be rolled 2. ing. Furthermore, the tooth thickness of the biting teeth, that is, the tooth thickness of the helical teeth 12 in the biting tooth group 13, is a normal thickness corresponding to the shape of the teeth to be finally formed on the rolled object 2, as shown in FIG. The tooth thickness t is set to be thinner than the tooth thickness T of .

Further, the finishing tooth group 14 includes the biting tooth group 1.
The incomplete teeth formed on the object 2 by step 3 are
The helical teeth 12 in the finishing tooth group 14, that is, the finishing teeth, are made of so-called finishing teeth for finishing into regular teeth, and the finishing teeth further include a first small group 14a.
and a second small group 14b. The first
The small group 14a is made up of helical teeth 12 that are at least half the number of teeth to be formed on the object to be rolled 2,
The tooth width of the helical teeth 12 here is set to be the same as the tooth width L of the biting tooth group 13, and the tooth thickness T matches the desired tooth shape to be formed on the rolled object 2. It is set to regular dimensions. Therefore, the first small group 14a in the finishing tooth group 14 is configured to form the incomplete teeth formed on the rolled object 2 by the biting tooth group 13 into regular-shaped teeth. There is. On the other hand, the second small group 14b in the finishing tooth group 14 is for correcting the tooth trace error of the teeth formed on the object to be rolled 2, and has at least half the number of teeth in the object to be rolled 2. is composed of helical teeth 12, that is, finishing teeth, and the face width l of the helical teeth 12 acting on the rolled object 2 (shown as the dimension in the width direction of the base body 11 in the figure) is the width of the helical teeth 12 acting on the rolled object 2. It is set to a constant width smaller than the tooth width W in the structure 2, and both ends of the tooth width l are set inside in the width direction of the base body 11 than the ends of the helical teeth 12 in the first small group 14a. To further explain the face width l of such a narrow finished tooth 16 that acts on the product 2 to be rolled, the action width l is approximately an integral multiple of the pitch interval Pa in the axial direction of the teeth in the product 2 to be rolled, For example, it is preferable to set the dimensions as shown by the following formula.

n・Pa−0.1Pa≦l≦n・Pa+0.1Pa (n is a natural number) On the other hand, the ends of the narrow finished teeth 16, especially the ends where they start meshing with the teeth of the rolled object 2 (in FIG. 5B, The distance between the lower end (lower end) and the side edge of the base 11 is set to, for example, half the pitch distance (Pa/2).

Further, the tooth depth and tooth thickness in the second small group 14b may be regular tooth depth and tooth thickness as in the first small group 14a, but the helical teeth 12 in the second small group 14b are Since the main purpose is to correct the tooth trace error, the tooth height h in the second small group 14b is As shown in FIG. 7, it is preferable to make the tooth depth slightly (for example, about 0.02 to 0.1 mm) lower than the normal tooth height H so that the tooth tip does not interfere with the tooth bottom portion of the rolled object 2.

In addition, FIG. 5B shows the rolled material 2 of the helical teeth 12.
This figure shows only the part that acts on the helical teeth 12 before the first small group 14a, and the actual tooth width of the helical teeth 12 after the second small group 14b is shown in FIG.
However, it may be difficult to manufacture a flat die 10 having such a shape, or the variation in the load acting on the rolled material 2 may become large, or the width of the rolled material 2 may be smaller than the width of the face. There is a risk that a step may form on the tooth surface of the tooth. Therefore, in order to prevent such inconvenience, the helical teeth 12 after the second small group 14b, that is, the end portions of the narrow finished teeth 16, are tapered to have a low tooth depth, as shown in FIG. 7, for example. However, the tooth thickness may be formed into a thin tapered shape. In that case, both tooth surfaces may be ground down to reduce the tooth thickness, or one tooth surface may be ground down to reduce the tooth thickness.

Furthermore, the relief tooth group 15 includes a plurality of teeth whose tooth width acting on the object to be rolled 2 is the same as the working tooth width l of the narrow finishing teeth 16 and whose tooth height gradually decreases toward the other end of the base body 11. It is formed by helical teeth 12.

Next, the operation of the flat die 10 configured as described above will be explained.

The rolling of the helical gear 1 using the flat dies 10 is carried out by sandwiching the object 2 between the pair of flat dies 10 and moving the flat dies 10 in opposite directions as shown in FIG. 5A. , by rotating the object 2 to be rolled accordingly. At the beginning of rolling, the helical teeth 12 of the biting tooth group 13 first bite into the object 2 to be rolled. In this case, since the tooth depth of the biting tooth group 13 is gradually increasing, the amount of biting into the object to be rolled 2 gradually becomes deeper, and as a result, the outer peripheral part of the object to be rolled 2 is plastically deformed and teeth are formed. Ru. The teeth thus formed on the rolled object 2 are so-called rough teeth or incomplete teeth, and the tooth thickness t in the biting tooth group 13 is formed to be thinner than the regular tooth thickness T. , the teeth are rough-shaped or incomplete teeth with a thick tooth thickness, and large undulations have occurred on the tooth surface as shown by the solid line in FIG. 8, resulting in a large tooth trace error. Following the biting tooth group 13, the helical teeth 12 of the first small group 14a in the finishing tooth group 14
By meshing with the teeth of the rolled object 2, the teeth are shaped into so-called perfect teeth. In that case, since the tooth thickness of the first small group 14a is set to the regular tooth thickness T, the tooth surface of the object to be rolled 2 is pushed in until it reaches the regular tooth thickness, but the first small group 14a Since the tooth width L is the same as the tooth width of the biting tooth group 13, the same waviness or tooth trace error occurs as shown by the chain line in FIG. 8.

The teeth formed on the outer periphery of the object to be rolled 2 as described above are in the second small group 1 following the first small group 14a.
4b, helical teeth 12 or narrow finished teeth 1
6, and further finishing processing is performed here.
Helical tooth 12 and rolled object 2 in second small group 14b
Even while rolling is being performed by meshing the teeth of Waviness occurs on the tooth surface of No.2. The starting end of the undulation becomes the meshing start end of each tooth, and therefore the acting tooth width l on the rolled object 2 at the second small end 14b is smaller than the face width W of the rolling object 2, and the meshing starts. Since the end is located inward by Pa/2 in the width direction of the base body 11, the waviness that acts on the tooth surface of the rolled object 2 due to the narrow finished tooth is already generated on the tooth surface, as shown by the broken line in FIG. The wave is 1/2 out of phase with the current wave. That is, by rolling up to the first small group 14a described above, among the undulations that were generated in the tooth trace direction on the tooth surface of the rolled object 2, the portion that becomes a mountain becomes the second small group. It is crushed by the undulations that occur as a result of rolling with the narrow finishing teeth 16 after 14b. Further, in the first small group 14a or the biting tooth group 13,
As shown in FIG. 9, the tooth tips interfere with the workpiece 2 to be rolled, but the tooth depths after the second small group 14b are set lower than the tooth depths corresponding to the teeth to be formed on the workpiece 2 to be rolled. Therefore, when rolling with the narrow finishing teeth 16 after the second small size 14b, the tips of the narrow finishing teeth 16 touch the object 2 to be rolled, as shown in FIG.
It does not interfere with the bottom of the tooth, and therefore only corrects errors on the tooth surface. In particular, in the above-mentioned flat die 10, the tooth thickness T of the narrow finished teeth 16 is set to the tooth group 1.
Since the tooth thickness is thicker than the tooth thickness t of No. 3, the narrow finished teeth 16 push the tooth surface of the object 2 more actively. As a result, the tooth surface of the rolled object 2 will ultimately be in a state of undulation as shown by hatching in FIG. 8, and the tooth trace error that had occurred on the tooth surface will be corrected.
Accuracy is significantly improved.

The rolled object 2 on which teeth of the desired size have been formed by the finishing tooth group 14 as described above is then meshed with the relief tooth group 15, but the tooth height of the relief tooth group 15 is gradually lowered. Since the load acting on the object to be rolled 2 gradually decreases, in other words, the object to be rolled 2 is not particularly processed, and eventually the mesh is disengaged and the rolling is completed. do.

Therefore, by setting the portion finished by the narrow finished teeth 16 to the tooth width used when used as a product, a highly accurate helical gear can be obtained.

The key point of this invention is to form within the finishing tooth group 14 narrow finishing teeth 16 whose working tooth width is narrower than the width of the teeth in the object to be rolled 2 and which is at least half the number of teeth to be formed in the object to be rolled 2. However, it is sufficient that the tooth thickness of the narrow finished teeth 16 is set to the regular tooth thickness, and the tooth thickness of the biting tooth group 13 is set thin, and the arrangement of the narrow finished teeth 16 is shown in FIG. It is not limited to the arrangement shown in B. Hereinafter, other embodiments of the present invention will be described in which the arrangement of the narrow finishing teeth 16 or the working tooth width is different from the above embodiments. In addition, the tooth thickness T of the narrow finished tooth 16 in each example described below is set to the regular tooth thickness, whereas the tooth thickness t of the biting tooth group 13 is set to be thinner than the regular tooth thickness. There is.

FIG. 11A is a schematic diagram showing another embodiment of the present invention, and the flat die 10 shown here is used to form the teeth to be formed on the product 2 to be rolled, starting from the second small group 14b in the finishing tooth group 14. It is further divided into small groups consisting of at least half of the number of narrow finished teeth 16, and the face width l acting on the rolled material 2 in each small group is made constant, and the portion of the working teeth is divided into each small group. They are alternately shifted left and right in the width direction of the base body 11.

When rolling is performed with the flat die 10 having such a configuration, the waviness that occurs in the teeth of the rolled product 2 from the start of rolling to the first small group 14a of the finishing tooth group 14 is as shown in FIG. 11B. The state shown by the solid line in FIG. 11B is the state shown in FIG. The phase is shifted, and the depth of bite of the rolled object 2 into the tooth surface becomes deeper. Therefore, the ridges of undulations that were occurring on the tooth surface of the rolled object 2 are
Since the teeth are gradually crushed, it is possible to obtain teeth with less tooth trace error, that is, a helical gear.

FIG. 12A is a schematic diagram showing still another embodiment of the present invention, and the flat die 10 shown here is used to form the second small group 14b and subsequent parts of the finishing tooth group 14 on the product 2 to be rolled. It is further divided into small groups consisting of narrow finishing teeth 16 that are at least half the number of teeth, and the face width l that acts on the rolled object 2 in each small group is constant, and the portion of the working teeth is divided into each small group. The width of the base body 11 is changed continuously in the width direction of the base body 11, and the overall shape is formed in a zigzag shape.

When rolling is performed with the flat die 10 having such a configuration, the end of the meshing start of the narrow finished teeth 16 with the object 2 to be rolled changes continuously, and accordingly, the tooth surface of the object 2 to be rolled changes. The phase of the waviness acting on the tooth changes continuously as shown by the broken line or chain line in FIG. Waviness generated on the tooth surface of the rolled object 2 due to rolling up to the first small group 14a (Fig. 12B)
The peaks (solid line) are gradually crushed, and as a result, a highly accurate helical gear with small tooth trace error can be obtained, as in each of the above-described embodiments.

Figure 13A, Figure 14A and Figure 15A are
This is a schematic diagram showing fourth to sixth embodiments of the present invention, and the flat die 10 shown in FIG. The width is changed into two levels: a minimum tooth width l ₂ smaller than the tooth width W to be formed on the object 2 to be rolled, and a tooth width l ₃ slightly wider than that. Further, the flat die 10 shown in FIG. 14A is
The working face width l of the narrow width finishing teeth 16 after the second small group 14b in the finishing tooth group 14 is made to gradually increase from the minimum face width l _{2 smaller than the face width W of the teeth to be formed on the object to be rolled 2} . This is the setting. Furthermore, the flat die 10 shown in FIG. 15A has a finishing tooth group 1.
Narrow finished teeth 1 after the second small group 14b in 4
The face width l of No. 6 is irregularly changed within a range equal to or less than the face width W of the teeth to be formed on the object 2 to be rolled.

No matter which of these flat dies 10 is used for rolling, since the starting end of the narrow finishing tooth 16 meshing with the object 2 to be rolled changes continuously, the tooth surface of the object 2 to be rolled changes accordingly. The phase of the acting waviness changes continuously as shown by the broken line or chain line in FIG. 13B, FIG. 14B or FIG. 15B,
As a result, undulations (as shown in Figs. 13B, 14B, and 15B) were generated on the tooth surface of the rolled object 2 due to rolling between the finished teeth group 14 and the first small group 14a. The mountain (solid line) is gradually crushed,
As a result, it is possible to obtain a highly accurate helical gear with small tooth trace errors, as in each of the embodiments described above.

In each of the above embodiments, the case where a helical gear is rolled has been explained as an example, but the flat die of the present invention can also be applied to the case where a helical groove such as an oil groove is rolled.

As is clear from the above description, in the flat die of the present invention, the phase of the waviness acting on the tooth surface of the workpiece due to the narrow width finishing teeth is such that the phase of the waviness acting on the tooth surface of the workpiece due to the narrow width finishing teeth is before the teeth of the workpiece are engaged with the narrow width finishing teeth. The phase of the undulations that occur on the surface is different, and the depth of the narrow-width finished teeth biting into the tooth surface of the rolled object is deep, so the narrow-width finished teeth can reduce the existing ridges of undulations. This ensures reliable crushing, and as a result, the tooth trace error on the tooth surface of the object to be rolled can be made as small as possible.
In addition, by making the tooth height of the narrow finishing teeth at least slightly lower than that of the preceding finishing tooth group or biting tooth group, the narrow finishing teeth can act exclusively on the tooth surface of the workpiece. As a result, fluctuations in the load acting on the object to be rolled and fluctuations in the object itself are reduced, so accuracy can be further improved. In this way, according to the flat die of the present invention, since it is possible to perform rolling with high precision, it becomes possible to roll helical gears, etc., which could not be put to practical use due to poor precision, and the productivity is significantly improved. It is possible to obtain excellent practical effects such as improved performance.

[Brief explanation of the drawing]

Figure 1 is a front view showing an example of a helical gear, Figure 2 is a schematic front view for explaining the rolling method of a helical gear, and Figure 3 is the number of meshing teeth and meshing point between the rolled object and the flat die. FIG. 4 is a schematic diagram of waviness occurring on the tooth surface of a rolled object, FIG. 5 A is a schematic side view showing an embodiment of the present invention, and FIG. FIG. 6 is a schematic partial perspective view showing one of the biting teeth, and FIG. 7 is a schematic partial perspective view showing one of the biting teeth. Partial perspective view showing the shape of the end that does not act on the rolled object, No. 8
The figure is a line diagram showing the waviness that occurs in the rolled object, FIGS. 9 and 10 are partial cross-sectional views showing the meshing state between the rolled object and the flat die, and FIG. 11A is another embodiment of the present invention. FIG. 5B is a schematic plan view similar to that shown in FIG.
Fig. 2A is a schematic plan view similar to Fig. 5B showing still another embodiment of the present invention, and Fig. 12B is a line showing the undulations generated on the tooth surface of the rolled material when it is rolled with the flat die. Fig. 13A is a schematic plan view similar to Fig. 5B showing the fourth embodiment of the present invention, and Fig. 13B shows the undulations that occur on the tooth surface of the rolled object when it is rolled with the flat die. FIG. 14A is a schematic plan view similar to FIG. 5B showing the fifth embodiment of the present invention;
Fig. 14B is a diagram showing the undulations that occur on the tooth surface of the rolled object when it is rolled with the flat die, and Fig. 15A
is a schematic plan view similar to FIG. 5B showing the sixth embodiment of the present invention, and FIG. 15B is a line diagram showing the undulations generated on the tooth surface of the rolled material when it is rolled with the flat die. . 2... Rolled object, 10... Flat die, 12...
Helical teeth, 13... Biting tooth group, 14... Finished tooth group, 14a... First small group (of the finished tooth group), 14b... Second small group (of the finished tooth group) , 16... Narrow finished tooth, L... Working tooth width in the biting tooth and the first small group, l, l ₂ , l ₃ ...
Working face width of the narrow finished tooth, T...Tooth thickness of the narrow finished tooth, t...Tooth thickness of the biting tooth group, W...Face width in the object to be rolled, Pa...Tooth width in the object to be rolled Pitch spacing in the axial direction.

Claims (1)

[Claims] 1. A finishing tooth group consisting of a plurality of finishing teeth is formed following a biting tooth group consisting of a plurality of biting teeth whose tooth heights are gradually increased, and are arranged opposite to each other with the object to be rolled sandwiched between them. In the flat rolling die, the tooth width of the biting tooth group is set to be larger than the tooth width of the tooth to be formed on the object to be rolled, and the tooth width of the tooth group to be formed on the object to be rolled is set to be larger than the tooth width of the tooth to be formed on the object to be rolled. At least half the number of finishing teeth are narrow width finishing teeth in which the width of the teeth acting on the object to be rolled is set narrower than the width of the teeth to be formed on the object to be rolled, and the narrow finishing teeth are narrow width finishing teeth. The starting end of meshing with the object to be rolled is set inside in the width direction than the starting end of meshing with the other finishing teeth or biting teeth, and the tooth thickness of the biting tooth group is set to be smaller than that of the narrow finishing teeth. A flat rolling die characterized by being formed thinner than the tooth thickness. 2. The tooth height of at least the narrow finishing tooth in the finishing tooth group is set to be slightly lower than the tooth height of the finishing tooth or biting tooth adjacent to the biting tooth group side with respect to the narrow width finishing tooth. A flat rolling die according to claim 1, characterized in that: