JPS6331296B2 - - 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 as 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 hob cutter finishing the cut. 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 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 Because the number of meshing teeth changes, a tooth trace error occurs. 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 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 rolled object 2 by the flat dies 3 and 4 changes. As a result, rolled object 2
Since the load acting on the rolled material 2 changes and the rolled material 2 is displaced or deformed even slightly in the direction indicated by the arrow in FIG. The pitch becomes undulating at the same pitch as the pitch interval Pa in the axial direction of the teeth.
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 actually impossible.

In this way, conventionally, since the tooth trace error is large when rolling is performed, it is possible to obtain rolled products such as helical gears with a precision that can be used for practical purposes. As a result, in many cases, helical gears and the like are manufactured by cutting.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pair of flat rolling dies that can accurately roll helical gears, helical grooves, etc. The feature of this invention is that a finishing tooth group is formed following a group of biting teeth whose tooth width is greater than the width of the teeth to be formed on the object to be rolled, and the tooth height is successively higher, and A pair of rolling flat dies arranged opposite to each other with the first flat die holding 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 inside 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. A second narrow-width finish in which a series of finishing teeth that act on the object to be rolled at the same time as the width finishing teeth are set so that the end of engagement 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 present invention is characterized in that both the first and second narrow finishing teeth are configured so that the width of their action 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 narrow finished teeth and other finished teeth or biting teeth. 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 are schematic diagrams showing flat dies 10, 20 according to the present invention, and the flat dies 10, 20 shown here have helical teeth 12, 22 formed on the surfaces of base bodies 11, 21. It is constructed as a flat die for helical gear rolling, and these helical teeth 1
2, 22, a plurality of helical teeth 12, 22 in a predetermined range from one end of the base 11, 21 (the right end in FIGS. 5 and 6) are attached to biting tooth groups 13, 23.
, followed by a plurality of helical teeth 1 in a predetermined range.
2 and 22 are used as finishing tooth groups 14 and 24, and a plurality of helical teeth 12 and 22 in a predetermined range on the other end side of the base bodies 11 and 21 are used as relief tooth groups 15 and 25. That is, the biting tooth groups 13 and 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. , 21, the tooth height of the helical teeth 12, 22 on the one end side is the lowest,
Helical teeth 12, 2 adjacent to finishing tooth groups 14, 24
The tooth height is set to gradually increase so that the tooth height of No. 2 is approximately the normal tooth depth. In addition, the face width L of the biting tooth groups 13, 23 (in the figure, the dimension in the width direction of the base bodies 11, 21) is the face width W (in the figure, the dimension in the axial direction) of the teeth to be formed on the rolled object 2. (indicated by ) or higher.

Further, the finishing tooth groups 14 and 24 are so-called finishing teeth for finishing the incomplete teeth formed on the object 2 to be rolled by the biting tooth groups 13 and 23 into regular teeth. , its finishing tooth group 1
The helical teeth 12, 22, ie, the finishing teeth in 4, 24 are further arranged in the first small group 14a, 24a to the fourth small group.
It is divided into four small groups: small groups 14d and 24d.
Each of these groups 14a to 14d, 24a to 24d is
The number of helical teeth 12, 22 is at least half the number of teeth to be formed on the object to be rolled 2, and the width of the teeth of the first small group 14a, 24a and the fourth small group 14d, 24d is equal to that of the biting teeth. The tooth width L in the groups 13 and 23 is set to be the same, and the tooth depth and tooth thickness are set to regular dimensions that match the shape of the desired tooth to be formed on the product 2 to be rolled. Therefore, the helical teeth 12, 22 of at least the first small group 14a, 24a in the finished tooth groups 14, 24 are as follows:
The object to be rolled 2 is
It is configured to form an incomplete tooth formed into a regular tooth.

On the other hand, the second small group 14b, 24b and the third small group 14c, 24c in the finished tooth groups 14, 24
is mainly for correcting the tooth trace error of the teeth formed on the rolled object 2, and among these, the second small die in the first flat die 10 shown in FIGS. 5A and 5B is The helical teeth 12 of the group 14b and the third small group 14c have their ends (lower ends in FIG. 5B) on the side where they begin to mesh with the object 2 to be rolled with a constant width X1 that does not particularly act on the object 2 to be rolled. , X2 (X1>X2), and the non-acting parts 1
The widths X1 and X2 of 6 are the width of the rolled object 2 and the base 11.
By setting the width to be equal to or greater than the difference between the widths of the teeth, narrow finished teeth 18b and 18c are formed in which the meshing start ends 17b and 17c with the object to be rolled 2 are inside in the width direction from the ends of the teeth in the object to be rolled 2. ing. In addition, to further explain the widths X1 and X2 of the non-working portions 16b and 16c, the dimensions of the widths X1 and X2 are half of the pitch interval Pa in the axial direction of the teeth in the rolled product 2, or half of the pitch interval Pa. It is preferable to use a dimension obtained by subtracting (Pa/2) from an integral multiple of the length.

Further, the helical teeth 22 of the second small group 24b and the third small group 24c in the second flat die 20 shown in FIGS. 6A and 6B are located at the end (sixth In Figure B, the upper end) is set to a constant width Y1, Y2 (Y1>Y
By making the non-working parts 26b and 26c of 2) and making the widths Y1 and Y2 of the non-working parts 26b and 26c the same as the widths X1 and X2 of the non-working parts 16b and 16c in the first flat die 10, the rolled object 2 Narrow width finishing teeth 28 whose engagement end ends 27b and 27c are inside in the width direction from the ends of the teeth in the object to be rolled 2.
b, 28c.

Therefore, in the pair of flat dies 10, 20, the second small group 14b, 2
The working width l2 of the narrow finishing teeth 18b and 28b of 4b is a constant width smaller than the tooth width W of the object to be rolled 2, and the meshing start end 17b and the meshing end end 27b are on the object to be rolled 2. The third small group 1 is set on the inside in the width direction of the rolled object 2.
The working width l3 in which the narrow finishing teeth 18c and 28c of 4c and 24c act together is a constant width smaller than the tooth width W of the rolled object 2, and the meshing start end 17c thereof
The mesh end end 27c is set on the inner side in the width direction of the object to be rolled 2. Furthermore, the width of its action l
To further explain 2, l3, its action width l
2 and l3 are preferably 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.

(n-0.1)Pa≦l2, l3≦(n+0.4)Pa (n is a natural number) In addition, the tooth depth and tooth thickness after the second small group 14b, 24b in each flat die 10, 20 are
As in the small groups 14a and 24a, regular tooth depth and tooth thickness may be used, but each narrow finished tooth 1
Since the main purpose of 8 and 28 is to correct the tooth trace error, the second small group The tooth depth after 14b and 24b is slightly smaller than the regular tooth depth (for example, 0.02 to 0.1
It is preferable to make the tooth tip as low as possible (approximately mm) so that the tooth tip does not interfere with the tooth bottom portion of the object 2 to be rolled.

Note that FIGS. 5B and 6B show helical teeth 12,
22, which shows only the part that acts on the rolled object 2, the diagonal lines in the figure indicate the tooth trace direction, and the actual tooth width of each narrow finished tooth 18b, 18c, 28b, 28c is As shown in FIG. B and FIG. 6B, the helical teeth 12, 2 before the first small group 14a, 24a
However, 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, both ends of each narrow finishing tooth 18b, 18c, 28b, 28c should be
For example, as shown in FIG. 7, the tooth height may be tapered to be low and the tooth thickness may be tapered to be thin. 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 flank teeth 15, 25 have a tooth width that acts on the object to be rolled 2 and is the same as the tooth width of the first small group 18a, 28a, and the tooth height gradually decreases toward the other end of the base bodies 11, 21. It is formed by a plurality of helical teeth 12 and 22.

Next, a pair of flat dies 1 configured as above
The effect of 0 and 20 will be explained.

Helical gear 1 formed by the flat dies 10 and 20
For rolling, the object 2 to be rolled is sandwiched between each of the flat dies 10 and 20, and in this state, each of the flat dies 10 and 20 is
This is carried out by moving the rollers in opposite directions and rotating the rolled object 2 accordingly. At the beginning of rolling, the helical teeth 12, 22 of the biting tooth groups 13, 23 first bite into the object 2 to be rolled. In this case, since the tooth depth of the biting tooth groups 13 and 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. The teeth formed on the object to be rolled 2 by the biting tooth groups 13 and 23 are so-called coarse teeth or incomplete teeth, but following the biting tooth groups 13 and 23, the finishing teeth group 14, 1st small group 14a, 24a in 24
By meshing the helical teeth 12 and 22 with the teeth of the object to be rolled 2, the teeth are shaped into so-called perfect teeth.

During rolling using the biting tooth groups 13, 23 and the first small groups 14a, 24a, the helical teeth 12, 22 begin to mesh from the axial end of the outer circumferential surface of the rolled object 2. In that case, as mentioned above, the rolled object 2 changes due to changes in the number of meshing teeth and the meshing point, so the cross section of the rolled object 2 becomes undulating as shown by the solid line in Fig. 8. This results in a large tooth trace error.

The teeth formed on the outer periphery of the rolled object 2 as described above are the helical teeth 12, 22 in the second small group 14b, 24b following the first small group 14a, 24a.
That is, further finishing is performed by meshing with the narrow width finishing teeth 18b, 28b. FIG. 9 shows a state in which the narrow finishing teeth 18b, 28b mesh with the object 2 to be rolled. As is clear from this figure, the width at which both the narrow finishing teeth 18b of the first flat die 10 and the narrow finishing teeth 28b of the second flat die 20 act on the workpiece 2 is the aforementioned action width. l
2, and these narrow finished teeth 18b, 2
The engagement start end 17b and the engagement end end 27b between 8b and the object to be rolled 2 are located inside of both ends of the teeth in the object to be rolled 2. Also, the third small group 14c, 2
The narrow finishing teeth 18c and 28c of 4c are the rolled object 2.
The same applies to the case where the teeth engage with each other, and the engagement start end 17c and the engagement end end 27c are located inside both ends of the teeth of the rolled object 2. By the way, in general, the waviness in the tooth trace direction accompanying the fluctuation of the rolled object 2 during rolling occurs from the meshing start end, so the narrow finished teeth 18b, 18c,
In the state where 28b and 28c are meshing with the object to be rolled 2, the actual mesh start end that starts pressing the tooth surface of the object to be rolled 2 is the meshing of the narrow finishing teeth 18b and 18c on the first flat die 10. starting end 1
7b and 17c, 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 chain lines and broken lines in FIG. As a result, by rolling between the first small groups 14a and 24a mentioned above, among the undulations that were occurring in the tooth trace direction on the tooth surface of the rolled object 2, the mountainous portions are Narrow finished teeth 18b of the small groups 14b, 24b and the third small groups 14c, 24c,
It is crushed by the undulations caused by rolling at 18c, 28b, and 28c. Also, the first small group 14a, 24a or the biting tooth group 13, 2
3, the tooth tip is attached to the rolled object 2 as shown in FIG.
However, since the tooth depths after the second small group 14b, 24b are set lower than the tooth depths corresponding to the teeth to be formed on the object to be rolled 2, the second
Narrow finished teeth 18b after the small groups 14b and 24b,
When rolling by 18c, 28b, 28c, the first
As shown in Figure 1, the narrow finished teeth 18b, 18
The tips of the teeth c, 28b, and 28c do not interfere with the bottom portion of the tooth to be rolled 2, so that errors in the tooth surface are only corrected. As a result, the second small group 14b, 24b
In rolling with the third small group 14c, 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.

The rolled object 2 on which teeth of the desired size have been formed by the finishing tooth groups 14, 24 as described above is then engaged with the fourth small group 14c, 24c, and then engaged with the relief tooth groups 15, 25. It fits, but the escape tooth group 15,2
5 is formed so that its tooth height gradually decreases, so the load acting on the rolled object 2 becomes gradually smaller. In other words, the rolled object 2 is not particularly processed, and finally The mesh is disengaged and rolling ends.

Therefore, the narrow finished teeth 18b, 18c, 2
By setting the portion finished by 8b and 28c, that is, the portion having the maximum working width l3, as the tooth width used when the product is used as a product, a highly accurate helical gear can be obtained.

FIG. 12 is a diagram showing another embodiment of the present invention, and a pair of flat dies 10, 20 shown here are
Each narrow finishing tooth 18, 28 for the object to be rolled 2
The action width l in which the two groups act together is the second small group 14b, 24
The width is configured to gradually increase from the minimum width l2 after b. That is, as shown in FIG. 12A, the finishing teeth from the second small group 14b onwards in the finishing tooth group 14 of the first flat die 10 have a side end portion on the side where they start to mesh with the object to be rolled 2. By continuously forming non-acting portions 16 whose width X is maximum on the first small group 14a side and gradually narrows thereafter, narrow finished teeth 18 having a narrow tooth width that acts on the object to be rolled 2 are obtained. Further, the finishing teeth after the second small group 24b in the finishing tooth group 24 of the second flat die 20 are as follows:
As shown in FIG. 12B, the width Y is the first small group 24 at the side end on the side where the engagement with the object to be rolled 2 is disengaged.
By forming a non-working part 26 that is maximum on the a side and gradually narrows thereafter, corresponding to the non-working part 16 of the first flat die 10, narrow finished teeth 28 are formed.
It is said that FIG. 12C is an explanatory diagram assuming a case in which flat dies 10 and 20 are stacked on each other in order to clarify changes in the working width l, and as shown in this figure, each of the non-working parts 16, The position and widths X and Y of 26 are formed such that the working width l gradually increases at the center in the width direction. Therefore, a pair of flat dies 10 and 2 shown in FIG. 12A and B
0, the position of the meshing start end 17 and the meshing end end 27 with respect to the object to be rolled 2 changes continuously after the second small group 14b, 24b.

When rolling is performed using a pair of flat dies 10 and 20 having such a configuration, the object to be rolled 2 is The undulations that occur in the teeth of
The state shown by the solid line in Figure D is the narrow finished tooth 1.
The undulations that occur when meshing with 8 and 28 are caused by the 12th
The phase is shifted as shown by the broken line or chain line in Figure D. Therefore, the ridges of the undulations that have formed 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, 20 are shown.
, each narrow finishing tooth 18,
The working width l of the teeth 28 acting together 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. 13A, the second small group 14b in the first flat die 10
The width
As a result, the finishing teeth from the second small group 14b onward are narrow finishing teeth 18 having a narrow tooth width that acts on the rolled object 2. Also, the second flat die 20
A non-working part 26 in which the width Y is irregularly expanded and contracted is formed at the side end of the small group 24b and subsequent parts that are out of mesh with the rolled object 2, and is the non-working part 16 of the first flat die 10. As a result, the finishing teeth after the second small group 24b are narrow finishing teeth 28 having a narrow tooth width that acts on the object to be rolled 2. FIG. 13C is an explanatory diagram assuming a case in which flat dies 10 and 20 are stacked on top of each other in order to clarify changes in the working width l, and as shown in this figure, each of the non-working parts 16, The action width l determined by 26
is formed to vary irregularly, so that the pair of flat dies 1 shown in FIGS. 13A and 13B
0 and 20 are configured such that the engagement start end 17 and engagement end end 27 with respect to the rolled object 2 change irregularly in the second small group 14b, 24b and thereafter.

When rolling is performed using a pair of flat dies 10 and 20 having such a configuration, the meshing start end 17 of the narrow finishing tooth 18 with the object 2 to be rolled changes irregularly and continuously. Accordingly, 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.
By rolling between 24a and 24a, the rolled object 2
Waviness that occurred on the tooth surface (solid line in Fig. 13 D)
As a result, as in each of the embodiments described above, a highly accurate helical gear with small tooth trace error can be obtained.

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 pair of flat dies 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 changes before it engages with the narrow width finishing teeth. Since the configuration is different from the phase of the undulations occurring on the tooth surface of the object, the existing ridges of the undulations will be crushed by the narrow finished tooth. Errors 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. As described above, with the pair of flat dies of the present invention, it is possible to perform rolling with high precision.
It is now possible to roll helical gears, etc., which could not be put to practical use due to poor precision, and it is possible to obtain excellent practical effects such as being able to significantly improve productivity.

[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. 5A is a schematic side view showing one flat die in an embodiment of the present invention; FIG. Fig. 5B is a schematic plan view showing one flat die in an embodiment of the present invention with parts that do not act on the rolled product omitted, and Fig. 6A is a schematic diagram showing the other flat die in an embodiment of the invention. A side view, FIG. 6B is a schematic plan view similar to FIG. 5B showing the other flat die,
Fig. 7 is a partial perspective view showing the shape of the non-working part;
The figure is a line diagram showing the waviness that occurs in the rolled object, Figure 9 is a schematic cross-sectional view showing the state in which each narrow finishing tooth is meshing with the rolled object, and Figures 10 and 11 are flat with the rolled object. FIGS. 12A and 12B are partial cross-sectional views showing the state of engagement with the dies, and FIGS.
Figure C is an explanatory diagram assuming the case where the respective flat dies are overlapped, and Figure 12 D is a diagram showing the undulations that occur on the tooth surface of the rolled object when rolling with the flat dies.
13A and 13B are schematic plan views similar to FIGS. 12A and 12B showing still another embodiment of the present invention, and FIG.
An explanatory view similar to FIG. 2C, and FIG. 13D are diagrams showing undulations generated on the tooth surface of the rolled object when it is rolled with the flat die. 2... Rolled object, 10, 20... Flat die, 12,
22... Helical teeth, 13, 23... Biting tooth group, 1
4, 24... Finished tooth group, 14a, 24a... First small group (of the finished tooth group), 14b, 24b...
2nd small group (of finished teeth group), 14c, 24
c... 3rd small group (of the finished tooth group), 14d,
24d... 4th small group (of the finished tooth group), 1
7, 17b, 17c...meshing start end, 27, 27
b, 27c...meshing end end, 18, 28, 18
b, 18c, 28b, 28c...Narrow finished tooth, L
...The working tooth width in the biting teeth and the first small group,
l, l2, l3... working width (due to narrow finished teeth), W... tooth width in the rolled object, Pa... pitch interval in the axial direction of the teeth in the rolled object.

Claims (1)

[Scope of Claims] 1. Finishing consisting of a plurality of biting teeth whose tooth width is greater than or equal to the width of the teeth to be formed on the object to be rolled, and whose tooth heights are successively higher, followed by a plurality of finishing teeth. In a pair of flat rolling dies on which a group of teeth is formed and which are arranged opposite to each other with a workpiece to be rolled in between, a first
Of the group of finishing teeth in the flat die, at least half the number of teeth to be formed on the object to be rolled is set such that the end of the meshing start with the object to be rolled is wider than the end of the teeth on the object to be rolled. A series of finishing teeth which are first narrow width finishing teeth set on the inside in the direction and which act on the object to be rolled at the same time as the first narrow finishing teeth among the finishing teeth in the second flat die, The end of meshing with the object is a second narrow finished tooth set inside in the width direction from the end of the tooth on the object to be rolled, and the first narrow finished tooth and the second narrow finished tooth 1. A pair of flat rolling dies, characterized in that both of the dies are constructed so that the width of their action on the object to be rolled changes. 2. The tooth length of at least each of the narrow finishing teeth among the finishing tooth groups in the first and second flat dies is the finishing tooth or biting 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 dies are set slightly lower than the tooth depth of the teeth.