JPS59202132A - A pair of flat dies for rolling - Google Patents

Abstract

PURPOSE:To obtain a rolled product having high accuracy by setting the width of a prescribed number of the teeth of both finishing tooth groups of a flat die pair for rolling such as helical gears having odd teeth at the specific narrow width of a varying width acting on a material to be rolled. CONSTITUTION:The helical teeth 12, 22 of flat dies 10, 20 have finishing groups 14, 24 in succession to leading tooth groups 13, 23 having the tooth width L larger than the width W of the teeth to be formed on a material to be rolled (gear) and having gradually increasing dedendum. The groups 14, 24 are segmented to the 1st and 2nd small groups 14a-14d, 24a-24d and the groups 14a, 24a are constituted of the teeth 12, 22 of half the number of the teeth to be formed on the gear or larger number and have the tooth width which is the same as the width L. The groups 14b and 14c, 24b and 24c are mainly for correcting the error of the tooth trace of the formed teeth. These teeth are formed as the 1st and 2nd narrow width finishing teeth 18b and 18c, 28b and 28c of which the beginning ends 17b and 17c, 27b and 27c of the intermeshing of the respective teeth 12 and the teeth 22 acting simultaneously on the gear with the gear are in the direction more transverse and inner than the tooth ends of the gear. The widths l2, l3 thereof acting on the gear are so set as to vary.

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 finish due to the cutting 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 method of rolling does not cause the above problems, but because it is a method that applies a large load to the object to be rolled and causes it to plastically deform, conventional methods cannot achieve sufficient accuracy. The reality is that the helical gear 1 is manufactured by cutting.

That is, when manufacturing the helical gear 1 by rolling, the object 2 to be rolled is inserted into a pair of flat dies 3. as shown in FIG.
4 and apply a load IMP, and in this state, each flat die 3.4 is moved in a relatively opposite direction to rotate the workpiece 2. In this case, the rolled object 2 and the flat die 3
．． Since the number of meshing teeth with 4 changes, a tooth trace error occurs. FIG. 3 is a diagram for explaining the movement of the meshing points, and when the rolled object 2 is at the position indicated by A with respect to the flat die 3, the two points are 81 points, 82 points, and 83 points. When the rolled object 2 moves relatively to the position shown by B in Fig. 3, they mesh at a total of 4 points, b1 point, b2 point, b3 point, and 14 points. The other flat die 4 and the rolled object 2 are opposite to the case shown in FIG.
When it is in the position shown, it meshes at 4 points, and when it is in the position shown at B, it meshes 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 number of meshing teeth and the meshing point change between one flat die 3 side and the other flat die 4 side. Since the point positions are different, the amount of pushing into the object 2 by the flat die 3.4 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 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. , such a thing is 3- Realistically impossible.

In this way, in the past, it was not possible to obtain rolled products such as helical gears with a precision that could be put to practical use due to the large tooth trace error when rolling was performed.As a result, in many cases, helical gears etc. were manufactured by cutting. The reality is that they are being manufactured.

This invention was made in view of the above circumstances, and is a method for rolling helical gears, helical grooves, etc. with high precision.
The object of the present invention is to provide a pair of flat rolling dies. The feature of this invention is that a finishing tooth group is formed following a biting tooth group in which only the teeth are successively taller when the width m is greater than the width of the teeth to be formed on the object to be rolled, and A pair of rolling flat dies that are arranged opposite to each other with the first flat die having a series of finishing teeth, the number of which is at least half the number of teeth to be formed on the object to be rolled, among the finishing tooth groups in the first flat die. The meshing start end with respect to the object to be rolled is a first narrow finished tooth set inward in the width direction from the end of the tooth in the object to be rolled, and the first narrow finishing tooth is set among the finishing teeth of the second flat die. 4- A series of finishing teeth that act on the object to be rolled at the same time as the width finishing teeth are provided with a second narrow tooth whose meshing end end with the object to be rolled is set inside in the width direction from the end of the tooth in the object to be rolled. The narrow width finishing teeth are used, and the narrow width finishing teeth are both configured so that the width of action of both the first and second narrow width finishing teeth on the object to be rolled changes. 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 the narrow finished teeth and other finished teeth or biting teeth, resulting in mountains. As a result, the entire tooth surface can be made as smooth as possible and errors can be reduced.

Embodiments of the present invention will be described below with reference to FIGS. 5 to 13.

5 and 6 show a flat die 10.2 according to the present invention.
0 is a schematic diagram showing the flat die 10.2 shown here.
0 is constructed as a flat die for helical gear rolling in which helical teeth 12.22 are formed on the surface of a base body 11.21. A plurality of helical teeth 12.22 at a predetermined turn from the right end in FIGS. 5 and 6 form a biting tooth group 13.23.
, followed by a plurality of helical teeth in a predetermined range 12.22
is the finishing tooth group 14.24, and the base body 11.2
A plurality of helical teeth 12.22 in a predetermined range on the other end side of 1 are
The relief tooth group is 15.25. That is, the biting tooth groups 13.23 are so-called biting teeth that gradually bite into the outer periphery of the cylindrical object 2 to be rolled to form so-called coarse teeth on the object 2 to be rolled. The tooth height of the helical teeth 12.22 on the one end side of . The tooth width is set so that only the teeth gradually become higher.Furthermore, the tooth width L (indicated by the dimension in the width direction of the base body 11.21 in t!l) in the biting tooth group 13.23 is It is set to be larger than the face width W of the helical tooth (indicated by the dimension in the axial direction in the figure).

Further, the finishing tooth group 14.24 is the biting tooth group 13.
．． The helical teeth 12.23 in the finishing tooth group 14.24 are so-called finishing teeth for finishing the incomplete teeth formed on the object 2 to be rolled by 23 into regular teeth.
22, that is, the finishing teeth further include the first small group 14a, 24
It is divided into four subgroups a to fourth subgroups 14d and 24d. Each of these groups 14a to 14d, 24a to 24
d is composed of helical teeth 12.22, which is at least half the number of teeth to be formed on the object to be rolled 2, and the first small group 14a
, 24a and the fourth small group 14d, 24d tooth widths are:
The tooth width is set to be the same as the tooth width in the biting tooth group 13.23, and the tooth height and tooth thickness are
The regular dimensions are set to match the shape of the desired tooth to be formed. Therefore, at least the first sub-group 14a, 24a of the helical teeth 12.2 in the finishing tooth group 14.24
2, the object to be rolled 2 is formed by the biting teeth group 13.23.
It is configured to form an incomplete tooth formed into a regular tooth.

On the other hand, the second small group 14b in the finishing tooth group 14.24,
24b and the third small group 14c, 24c are mainly for correcting the tooth trace error of the teeth formed on the object 2 to be rolled.
The second small group 14 in the first flat die 10 shown in (B)
1) and the helical teeth 12 of the third small group 14c, the end portion (the lower end in FIG. 5(B)) on the side where it starts to mesh with the object 2 to be rolled is fixed so that it does not particularly act on the object 2 to be rolled. Width X1, X2
By setting the non-working portions 16b and 16c as (Xl >
The meshing start ends 17b and 170 with the object to be rolled 2 are narrow finishing teeth 18b and 18C which are located inside in the width direction from the end of the tooth in the object to be rolled 2. Note that the non-working part 1
To further explain the widths X1 and X2 of 6b and 160, the dimensions of the widths Xi and X2 range from half of the pitch interval Pa in the axial direction of the teeth in the rolled product 2 or an integral multiple of the pitch interval Pa. It is preferable to set the dimension by subtracting (Pa/2).

Further, the helical teeth 22 of the second small group 24b and the third small group 24c of the second flat die 28-0 shown in FIGS. 6(A) and 6(B) are disengaged from the rolled object 2. The side end portions (upper end portions in FIG. 6(B)) are non-acting portions 26b, 260 with constant widths Y1, Y2 (Yl > Y2) that do not particularly act on the object to be rolled 2, and the widths Y1, Y2. The non-working parts 16b and 16C in the first flat die 10
By setting the dimensions to be similar to the widths X1 and X2 of the narrow finished teeth 28b, 280, the meshing end ends 27b, 270 with respect to the object to be rolled 2 are inside in the width direction from the end of the tooth in the object to be rolled 2. It is said that

Therefore, in the pair of flat dies 10 and 20, the working width I12 in which the narrow finishing teeth 18b and 28b of the second small group 14b124b act together on the workpiece 2 is the face width W of the workpiece 2. The meshing start end 17b and meshing end end 27b are set inward in the width direction of the object 2 to be rolled, and the narrow width of the third small group 14c, 24c is smaller than that of the object 2. The working width 13 where the width finishing teeth 18c and 28c act together is a constant width smaller than the tooth width W of the object to be rolled 2, and the meshing start end 17c and the meshing end end 27c are in the width direction of the object to be rolled 2. is set inside. In addition, to further explain the working widths 12 and I13, the working widths 12.13 are set to approximately an integral multiple of the pitch interval Pa in the axial direction of the teeth in the object to be rolled 2, for example, to a dimension expressed by the following formula. It is preferable.

(n −0,1) pa≦l 2. I13≦(n 10
．． 1) Pa (n is a natural number) Also, the second small group 14b in each flat die 10.20,
The tooth depth and tooth thickness after 24b are the first small group 14a, 2
As in 4a, the regular tooth depth and tooth thickness may be used, but since the main purpose of each narrow finished tooth 18.28 is to correct the tooth trace error, 1. 2
In order to prevent the load acting on the rolling object 2 and the displacement and deformation of the rolled object 2 as a whole, the tooth depth of the second small group 14b124b and the subsequent ones is slightly smaller than the normal tooth depth (for example, 0.02 to 0.1 g).
It is preferable to set the tooth tip to be low (approximately n) so that the tooth tip does not interfere with the tooth bottom portion of the object 2 to be rolled.

Note that FIGS. 5(B) and 6(B) show the helical teeth 12.
22, which shows only the portion that acts on the object to be rolled 2, in which the diagonal lines indicate the tooth trace direction, and each of the narrow finished teeth 18b, 18c, 28b.

The actual tooth width of 280 is shown in Figure 5 (B) and Figure 6 (B).
As shown in FIG.
．． Although the face width may be smaller than the face width of 22, it may be difficult to manufacture flat dies 10, 20 with such a shape, or the variation of the load acting on the rolled product 2 may become large, or There is a possibility that a step may be formed on the tooth surface of the rolled product 2. Therefore, in order to prevent such inconvenience, each narrow finished tooth 18b, 18c, 28b, 2
For example, as shown in FIG. 7, both end portions of 8c may have a shape in which only the teeth are lowered in a tapered shape and the tooth thickness is made thinner in a tapered shape. In that case, both tooth surfaces may be ground down to reduce the tooth thickness, or only one tooth surface may be ground down to reduce the tooth thickness.

Furthermore, the relief tooth group 15.25 has a tooth width that is the same as the tooth width of the first small group 18a, 28a, and is directed toward the other end of the base body 11.21. It is formed by a plurality of helical teeth 12.22 which gradually become lower.

Next, a pair of flat dies 10.20 configured as above
The effect of this will be explained.

To roll the helical gear 1 using the front flat dies 10 and 20, the object 2 to be rolled is sandwiched between the flat dies 10 and 20,
In this state, each of the flat dies 10 and 20 is moved in opposite directions, and the rolled object 2 is rotated accordingly. 1f, at the beginning of forming, the helical teeth 12.22 of the biting tooth group 13.23 bite into the object 2 to be rolled first. In this case, since the color depth of the biting tooth group 13.23 is gradually increasing, the amount of biting into the object 2 to be rolled becomes gradually deeper, and as a result, the outer circumference of the object 2 to be rolled 2 is plastically deformed and the teeth are It is formed. Biting tooth group 13.
The teeth formed on the object to be rolled 2 by 23 are so-called coarse teeth or incomplete teeth, but the biting tooth group 13.
23, followed by one barge. 12- When the helical teeth 12.22 of the first small group 14a124a in the tooth group 14.24 mesh with the teeth of the product to be rolled 2, the teeth become so-called perfect. Teeth are shaped.

These biting teeth group 13.23 and the first small group 14a
, 24a, the helical teeth 12 and 22 begin to mesh from the axial end of the outer circumferential surface of the object to be rolled 2, but in this case, as described above, the number of meshing teeth and the meshing Since the object to be rolled 2 fluctuates due to changes in the points, the tooth surface of the object to be rolled 2 is undulating as shown by the solid line in FIG. 8, resulting in a large tooth trace error.

The teeth formed on the outer periphery of the rolled object 2 as described above are
Following the first small group 14a, 24a, a second small group 14b,
Further finishing is performed by meshing with the helical teeth 12.22 in 24b, ie the narrow finishing teeth 18b, 28b. FIG. 9 shows a state in which the narrow finishing teeth 18b, 28b are engaged with the object 2 to be rolled. As is clear from this figure, the narrow finishing fi18 of the first flat die 10
b and the narrow finishing teeth 28b of the second flat die 20.
4- The width through which the operator acts on the object to be rolled 2 is the above-mentioned action width 12, and the meshing start end 17b and the meshing end end 271 between these narrow finishing teeth 18b, 28b and the object to be rolled 2 are
) are located inside both ends of the teeth in the object 2 to be rolled.

Also, the narrow finished teeth 180 of the third small group 14Cs 24C,
The same applies when 280 meshes with the object to be rolled 2, and the meshing start end 17C1 and meshing end end 27c are as follows.
It is located inside both ends of the teeth in the object to be rolled 2. By the way, in general, the waviness in the tooth alignment direction due to deformation of the rolled object 2 during rolling occurs from the meshing start end, resulting in a narrow width finish! 18ri, 18c.

28b, 280 are in mesh with the object to be rolled 2, the actual mesh start end that starts pressing the tooth surface on the object to be rolled 2 is the narrow finishing tooth 18b of the first flat die 10, Since the meshing start end 1711.17C of 18c is reached, the waviness that occurs in that case becomes a waviness that is out of phase with the waviness that has already occurred, as shown by the dark and broken lines in FIG. As a result, the first small group 14a described above,
By rolling up to 24a, the peaked portions of the undulations generated in the tooth trace direction on the tooth surface of the rolled object 2 are formed in the second small group 14b, 24b and the third small group. 1
4c, 24c narrow finished teeth 18b.

It is crushed by the undulations caused by rolling at 18c, 28b, and 28c. Also, the first small group 14a
, 24a or biting tooth group 13.23, the first
As shown in Figure 0, the tooth tips interfere with the object 2 to be rolled, but the tooth depths after the second small group 14b, 24b are lower than the tooth depths corresponding to the teeth to be formed on the object 2 to be rolled. Since it is set, the narrow finished teeth 18b after the second small group 14b, 24b.

When rolling by 18c, 28b, 28c, the 11th
As shown in the figure, narrow finishing teeth 18b, 18c.

The tips of the teeth 28b and 128c do not interfere with the bottom of the tooth in the object to be rolled 2, so that errors in the tooth surface are only corrected. As a result, the second small group 14b, 24b and the third small group 140
．． In rolling at 24C, the tooth trace error occurring on the tooth surface of the object to be rolled 2 is corrected, and the accuracy is significantly improved.

15- The rolled workpiece 2 on which teeth of the desired dimensions have been formed as described above by the finishing tooth group 14.24 is then passed through the fourth small group 14.
After meshing with 0.240, it meshes with the relief teeth group 15.25, but since the relief teeth FIY 15.25 are formed so that their tooth heights gradually become lower, here, they act on the material to be rolled 2. The applied load gradually decreases, in other words, the object 2 to be rolled is not particularly processed, and eventually the guard is removed and the rolling is completed.

Therefore, narrow width finishing south 18h, 18c, 2811
．． The part finished with 28C, that is, the maximum working width is 1!
Use 1 when using 30 parts as a product! By setting the if width, it is possible to obtain a helical gear with good precision.

FIG. 12 is a diagram illustrating another embodiment of the present invention, in which a pair of flat dies 10. The action acting together is such that the width gradually increases from the minimum width 12 after the second small group 14! As shown in FIG. 12(A), the finished teeth from the small group 14b onward have a width X at the side end on the side where they start meshing with the object to be rolled 2. By continuously forming non-acting portions 16 that gradually become narrower, a narrow finishing fi 118 with a narrow tooth width that acts on the object to be rolled 2 is achieved. As shown in FIG. 12(B), the finishing teeth from the second small group 24b onward have a width Y at the side end on the side where the meshing with the object to be rolled 2 is disengaged from the first small group 2.
By forming a non-working part 26 that is maximum on the 41 side and gradually narrows thereafter, corresponding to the non-working part 16 of the first flat die 10, the finished tooth 28 has a narrow width. FIG. 12(C) is an explanatory diagram assuming a case where flat dies 10.20 are stacked one on top of the other in order to clarify the change in the working width a, and as shown in this figure, each of the non-working parts 16.2
The position and widths X and Y of 6 are the working widths! is formed so as to gradually expand at the center in the width direction. Therefore, a pair of flat dies 10 shown in FIGS. 12(A) and 12(B).
20 is configured such that the positions of the mesh start end 17 and the mesh end end 27 with respect to the object to be rolled 2 change continuously after the second small group 14b, 24b.

When rolling is performed with a pair of flat dies 10.20 having such a configuration, the finishing tooth group 1 is formed from the biting tooth group 13.23.
The waviness that occurs in the teeth of the rolled object 2 between the first small groups 14a and 24a of No. 4 is in the state shown by the solid line in FIG. Since the meshing start end 17 changes continuously, the undulations that occur during this process are out of phase as shown by broken lines or chain lines in FIG. 12(D). Therefore, the ridges of the undulations that have occurred on the tooth surface of the rolled object 2 are gradually crushed, so that it is possible to obtain teeth without tooth trace errors, that is, a helical gear.

FIG. 13 is a diagram showing still another embodiment of the present invention, in which a pair of flat dies 10 and 20 shown in FIG.
The working width that each narrow finishing tooth 18.28 acts together on! is changed irregularly within a range equal to or less than the width W of the teeth to be formed on the object 2 to be rolled. That is, as shown in FIG. 13(A), the second flat die 10
Small group 14bl! The width X irregularly expands and contracts at the side end on the side where it starts to engage with the rolled object 2, and the rolled object 2
A non-acting portion 16 is formed that does not act on the rolling material 2, and as a result, the finishing teeth from the second small group 14b onward are narrow finishing teeth 18 with a narrow m@ that acts on the rolled object 2. Also the second
A non-working part 26 whose width Y is irregularly expanded and contracted is located at the side end of the flat die 20 on the side where the second small group 24b and subsequent parts are out of mesh with the rolled object 2. 10, and as a result, the finishing teeth from the second small group 24b onwards are narrow finishing teeth 28 having a narrow tooth width that acts on the object to be rolled 2. 13th
Diagram (C) shows the action width! This is an explanatory diagram assuming a case in which flat dies 10.20 are stacked on top of each other in order to clarify the changes in the width of the action determined by the non-action portions 16.26. are formed to vary irregularly, 19- Therefore, the pair of flat dies 10, 20 shown in FIGS.
The meshing start end 17 and meshing end end 27 with respect to the object to be rolled 2 are configured to change irregularly.

When rolling is carried out using a pair of flat dies 10.20 having such a configuration, the meshing start end 17 of the narrow finished teeth 18 with the object 2 to be rolled changes irregularly and continuously. As a result, the phase of the waviness acting on the tooth surface of the rolled object 2 changes continuously as shown by the broken line or chain line in FIG. , 248, the ridges of undulations (solid line in FIG. 13(D)) that had occurred on the tooth surface of the rolled object 2 were gradually crushed, and as a result, each of the above-mentioned examples As in the case of , it is possible to obtain a highly accurate helical gear with small checking errors.

In each of the above embodiments, the case of rolling a helical gear was explained as an example, but the 20-flat die of the present invention can also be applied to the case of rolling a helical groove such as an oil groove. .

As is clear from the above description, in the pair of flat dies of the present invention, the phase of the waviness that acts 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 changes before the phase of the waviness of the workpiece is applied to the workpiece before it meshes with the narrow width finishing teeth. Since the configuration is different from the phase of the undulations occurring on the tooth surface, the existing ridges of the undulations are crushed by the narrow finished tooth, so the tooth trace error on the tooth surface of the rolled object can be minimized. can be made smaller. In addition, by making at least the tooth height of the narrow finishing teeth slightly lower than the tooth height 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 pair of flat dies of the present invention, since it is possible to perform rolling with high precision, it is possible to roll helical gears, etc., which could not be put to practical use due to poor precision, and the production thereof is improved. It is possible to obtain excellent effects in practical use, such as significantly improving properties.

[Brief explanation of drawings]

Fig. 1 is a front view showing an example of a helical gear, Fig. 2 is a schematic front view for explaining a helical gear rolling method, and Fig. 3
The figure is an explanatory diagram for explaining changes in the number of meshing teeth and the meshing point between the rolled material and the flat die, Figure 4 is a schematic diagram of waviness occurring on the tooth surface of the rolled material, and Figure 5 (A ) is a schematic side view showing one flat die in an embodiment of the present invention, and FIG. A plan view, FIG. 6(A) is a schematic side view showing the other flat die in an embodiment of the present invention, and FIG. 6(B) is a schematic diagram similar to FIG. 5(B) showing the other flat die. A plan view, FIG. 7 is a partial perspective view showing the shape of the non-working part, FIG. 8 is a line diagram showing the undulations that occur in the object to be rolled, and FIG. 9 is a diagram showing how each narrow finishing tooth meshes with the object to be rolled. 10th schematic cross-sectional view showing the state in which
11 and 11 are partial cross-sectional views showing the meshing state of the object to be rolled and the flat die, respectively, and FIGS. 12(A) and 12(B) are views of other parts of the invention in which parts that do not act on the object to be rolled are omitted. A schematic plan view showing each flat die in the example, the first
Figure 2 (C) is an explanatory diagram assuming the case where the respective flat dies are overlapped, and Figure 12 (D) is a miniature diagram showing the undulations that occur on the tooth surface of the rolled object when rolling with the flat dies. FIGS. 13(A) and 13(B) show a twelfth embodiment showing still another embodiment of the present invention.
Figures (A) and (B) are similar simplified plan views, and Figure 13 (C) is a diagram showing a different case where the respective flat dies are superimposed.
) A similar explanatory diagram, FIG. 13(D), is a diagram showing the waviness produced on the tooth surface of the rolled material when it is rolled with the flat die. 2... Rolled object, 10.20... Flat die, 1
2.22... Helical tooth, 13.23... Biting tooth group, 14.24... Finishing tooth group, 14a, 24a...
・First small group (of finished tooth group), 14b, 24b
...Second small group (of the finished tooth group), 14c, 24
C... 3rd small group (of finished tooth groups), 14d
, 24d... 4th small group (of the finished tooth group), 23
- 17.17b, 170...meshing start end, 27.2
7b, 27c...meshing end end, 18.28.18
b118c, 28b, 280=Narrow finished tooth, L...
Working tooth width in biting tooth and first small group, 11, 1
2.13 - Working width (due to narrow finished teeth), W...
Face width in the object to be rolled, pa - Pitch interval in the axial direction of the teeth in the object to be rolled. Applicant Toyota Motor Corporation Kobe 11a Office Representative Patent Attorney Yutaka 1) Takehisa (and 1 other person) 25- 24- Figure 1/1 Figure 13 (0) Continued from page 1 0 Inventor Yamazaki 179-1 Kanegasaki Nishi-Inuike, Uozumi-cho, Bunmeiseki-shi, Kobe Steel, Ltd. 0 Inventor: Takuji Moriguchi, Akashi-shi, Uozumi-cho, Kanegasaki Nishi-Inuike 179-1, Kobe Steel, Ltd., Akashi Plant ■Applicant: Stock Company Kobe Steel, Ltd. 1-3-18 Wakihama-cho, Chuo-ku, Kobe City

Claims (2)

[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 in which only the teeth become taller when the tooth width is greater than the width of the teeth to be formed on the object to be rolled. In a pair of flat rolling dies arranged oppositely with the object to be rolled in between, a series of at least half of the number of teeth to be formed on the object to be rolled out of the group of finishing teeth on the first flat die is used. The finishing tooth is a first narrow finishing tooth whose meshing start end with respect to the object to be rolled is set inside in the width direction from the end of the tooth in the object to be rolled, and the finishing tooth of the second flat die is Among them, a series of finishing teeth that act on the object to be rolled at the same time as the first narrow finishing teeth have their ends of meshing with the object to be rolled set inside in the width direction from the ends of the teeth in the object to be rolled. A second narrow width finishing tooth, and further characterized in that both the first narrow width finishing tooth and the second narrow width finishing tooth are configured such that the working width acting on the rolled object changes. A pair of flat rolling dies. (2) Among the finishing tooth groups in the first and second flat dies, at least the teeth of each narrow width finishing tooth are the finishing teeth or teeth adjacent to the biting tooth group side with respect to each narrow width finishing tooth. A pair of flat rolling dies according to claim 1, characterized in that the tooth depth is set slightly lower than the tooth depth of the biting teeth.