JPS6024243A - Flat die for rolling crown tooth - Google Patents

Abstract

PURPOSE:To form tapers in different directions to the teeth of a work and to roll crown teeth by constituting the finishing tooth group of flat dies in such a way that the trace helix angles of the 1st tooth group and the 2nd tooth group thereof are opposite to each other. CONSTITUTION:Flat dies 3a, 3b consist both of a chamfer tooth group KU, a finishing tooth group S1 and a relief tooth group N1 and the group S1 is constituted of the 1st tooth group S1- I and the 2nd toogh group S1-II. The tooth T1 of the group S1- I in this stage is provided with the trace helix angle larger by some angle beta than the trace helix angle of the work. On the other hand, the tooth T2 of the group S1-II is provided with the trace helix angle smaller by some angle beta than the trace helix angle of the work. A pair of the flat dies 3a, 3b having the same constitution are disposed to face each other with the work 4 in-between and are moved in the opposite directions. Therefore the tooth T1 forms a tooth face 3c to the work 4 and the tooth T2 a tooth face 3d thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flat die for rolling crown teeth on workpieces such as gears and splines.

Conventionally, in general, the tooth surface of gears, splines, etc.
It is formed into a curved surface as shown in the figure (such a tooth will be referred to here as a crown tooth).

As shown in the figure, the tooth surface 1a of the crown tooth 1 has a shape in which the center part 1b of the tooth bulges out from both ends IC with respect to the center line 0' of the tooth 1, which is parallel to the rotation axis of the workpiece. In other words, it has a crown shape. This bulging amount α is generally 10μ
That's about it.

In this way, by using teeth such as gears as crown teeth,
It is possible to absorb errors in the meshing of gears, etc., and to prevent the teeth from seizing by sufficiently distributing lubricating oil between the meshing teeth.

Incidentally, although it is well known that gears and the like can be manufactured by rolling using a flat die, a method of creating crown teeth by this rolling has not been attempted in the past.

When trying to create crown teeth by rolling with a flat die, it is easy to imagine that each tooth surface 2a of each tooth 2b of the flat die 2 can be shaped like a gear, etc., as shown in FIG. Corresponding to the crown tooth 1, the tooth surface has a curved shape in which both ends bulge out from the center, that is, a flattened shape. However, in practice, it is extremely difficult to process each tooth 2b of the flat die 2 into such a curved surface shape.

The present invention provides a flat die with a novel configuration that is easy to manufacture and can create and impart desired crown teeth to a workpiece.

In order to achieve the above object, the flat die according to the first invention was constructed as follows.

That is, the finishing tooth group is a first tooth group consisting of teeth having a tooth helix torsion angle slightly larger than the tooth shear torsion angle of the workpiece;
It is characterized by comprising a second tooth group consisting of teeth having a tooth trace torsion angle slightly larger than the tooth trace torsion angle of the workpiece.

If rolling is performed using two flat dies with the above configuration as a set,
A desired crown tooth can be created on the workpiece. Since the tooth thickness of each tooth of this flat die changes linearly, it is easy to process the teeth, and there is no difficulty involved in forming teeth whose tooth thickness changes two-dimensionally as shown in Figure 3. do not have.

According to the flat die with the above configuration, when the first tooth group of one flat die acts on the workpiece, the first tooth group of the other flat die also acts on the workpiece. acts,
When the second tooth group of one flat die acts on the workpiece, the second tooth group of the other flat die also acts. In other words, the inclination directions of the working teeth of both flat dies that simultaneously act on the workpiece are opposite. therefore,
The working teeth of each flat die cause the torsional direction of the workpiece to be reversed, meaning that the torsions cancel each other out, and the workpiece is machined in a stable state.As a result, the workpiece The finishing accuracy is very good. If the inclination directions of the working teeth of the two-handed dies are the same, the working teeth of both dies will act to twist the workpiece in one rotation direction, which will cause the support shaft of the workpiece to swing and stabilize machining. Otherwise, the finishing accuracy of the workpiece will deteriorate.

A flat die according to a second invention is characterized in that, in the configuration of the first invention, it further includes a third tooth group consisting of teeth having the same tooth helix angle as the tooth helix angle of the workpiece. There is.

According to the flat die according to the first invention, if the change in the tooth thickness of each tooth of the first and second tooth groups is extremely small, there is no problem, but if the change in tooth thickness exceeds a certain value, The center of the teeth of the workpiece tends to protrude significantly. If this protrusion is too large, the crown shape will be far from ideal. The second invention solved this problem.

The third tooth group may be provided in front of the first tooth group, between the first tooth group and the second tooth group, or behind the second tooth group, or may be provided in multiple locations. .

When the third tooth group is provided in front of the first tooth group, the thickness of the rough finishing teeth of the workpiece is predetermined by the third tooth group before the first tooth group acts on the workpiece. value, thereby preventing an extreme bulge in the center of the teeth of the workpiece due to the action of the first and second tooth groups.

When the third tooth group is provided between the first tooth group and the second tooth group or after the second tooth group, the central part of the teeth of the workpiece produced by the action of the first tooth group and the second tooth group The bulge is corrected by the third tooth group.

The present invention will be specifically described below with reference to the embodiments shown in FIGS. 4 to 15.

No. 41'71+I+, (In m, 3a and 3b are a pair of flat dies, and 4 is a workpiece such as a gear.The pair of flat dies 3a and 3b and the workpiece (for example, a gear) 4 are not shown. The workpiece 4 is installed in a rolling machine.As shown in the figure, the workpiece 4 is installed rotatably in the direction of the arrow, and a pair of flat dies 3a, 3b are mounted on both sides of the workpiece 4 so as to sandwich the workpiece 4, and have different reciprocating speeds. It is installed at the position of the dynamic dead center.
The pair of flat dies 3a, 3b has tooth arrangement surfaces 3e, 3.
They are mounted on the rolling device so that the fs are parallel to each other and also parallel to the rotation axis O of the workpiece 4.

By the way, the pair of flat dies 3a and 3b have the same configuration, and the flat dies 3a and 3 according to one embodiment of the first invention.
The configuration of b is as shown in FIG.

In Fig. 5, KU is the tooth group with bite, SI is the finished tooth group,
NI is a group of escape teeth.

For the above purpose, the tooth groups are the first tooth group 5r-i and the second tooth group sr-■.
It consists of

Tooth "1"1 of the first tooth group 5r-T has a tooth helix angle of the workpiece (in the case of a spur gear as shown in the embodiment, this angle is 0).
It has a tooth lead torsion angle that is slightly larger by an angle β than the following. On the other hand, teeth T21-1 of the first tooth group Sl-■],
It has a tooth trace torsion angle that is slightly smaller than the tooth trace torsion angle of the workpiece by an angle β.

It goes without saying that the length of each region of the first tooth group ST-J and the second tooth group 5I-If is at least 1/2 of the pitch circumference of the workpiece.

As mentioned above, a pair of flat dies 3a having the same configuration,
3 +) are arranged to face each other with the workpiece 4 in between, as shown in FIG.
The teeth 3aT of the first tooth group 5r-T of the flat die 3b and the teeth 3b-T of the first tooth group Sl-■ of the flat die 3b are seen in a superimposed state as shown in FIG. (As shown in Il, that is, the twisting directions of the teeth 3a-T□ and 3b-T□ are reversed. Also, the second tooth group SI of one flat die 3a
-]') tooth 3a T2 and the second tooth group S of the flat die 3b, teeth 3b-T2 of I-II are shown in Fig. 7 (9) when viewed through the superimposed state. As shown,
In other words, the twisting directions of these teeth 3a-T and 3b-T2 are opposite.

The effect of each of the above teeth T□ and T2 on the workpiece is expressed as seventh
Looking at the figure, the teeth T□ and T2 are the teeth 4a of the workpiece 4.
It is created so that it has a tapered shape in different directions.

In the figure, 3C represents the tooth surface of the workpiece 4 created by the tooth T0, and 3d represents the tooth surface of the workpiece created by the tooth T2.

Therefore, the crown tooth 4a created by rolling using the flat die according to the present invention becomes as shown in FIG. That is, the tooth surface of the tooth 4a is composed of two curved surfaces (involute curved surfaces) 4b and 4C, and the central portion of the tooth 4a where the curved surfaces 4b and 4c intersect bulges out from both ends thereof. Therefore, strictly speaking, this tooth surface is composed of two curved surfaces, and is not one curved surface as in the conventional example shown in Fig. 1.2, but as mentioned above, the central part of the tooth surface Since the amount of bulge is only about 10μ, the curved surface made up of these two curved surfaces is infinitely close to the one curved surface. This curved surface sufficiently achieves the purpose of crown teeth, which is to make the central part of the tooth surface bulge out from both ends of the tooth surface.

By the way, when each tooth T□ (or T2) of each flat die acts on the workpiece 4, since each tooth T□ has a constant tooth helix twist angle, the workpiece 4 is twisted. It works like this. That is, if we explain this according to Figure 9, now,
The tooth T1 of one flat die 3a is the tooth 4 in front of the workpiece 4.
act on the tooth T of the other flat die 3b in the direction of the arrow.
□ acts on the rear tooth / in the direction of the opposite arrow. In other words, the flat die 3a tries to twist the workpiece 4 in the direction of the solid arrow X, and the flat die 3b tries to twist the workpiece 4 in the opposite direction of the arrow Y. However, since these forward and reverse torsional forces are equal, they cancel each other out, and as a result, the workpiece 4 is rolled in a very stable state. This can be better understood by considering the case where the twisting direction of the tooth 3b-T1 is the same as that of the middle tooth 3a-T0 in FIG. In this case, since the teeth 3a-T and ab-T1 of both flat dies act to twist the workpiece 4 in the direction of the arrow X, the workpiece 4 is shaken and becomes unstable. This results in rolling, and the accuracy of the rolling process also deteriorates.

The detailed description of the first invention is as above.

Next, each embodiment of the second invention will be described.

As described above, the second invention comprises, in addition to the first tooth group and the second tooth group in the first invention, straight teeth, that is, teeth having the same tooth helix angle as the teeth 4a of 1% of the workpiece. It is characterized by the provision of the third m group. FIG. 10 shows one embodiment.

As shown in the figure, in this embodiment, the finishing tooth group ST
In addition to the first tooth group 5I-1 and the second tooth group 5l-II, which are similar to those described in FIG. It forms Q.

The third tooth group 5I-Q is composed of straight teeth To that are not tapered like teeth Tt and T2.

When rolling is performed using a pair of flat dies having the above configuration, first, each straight tooth To of the third tooth group 5l-Q of the second group acts on the workpiece 4. That is, as shown in FIG. 11 (1), the tooth 4a of the workpiece 4 with a thick tooth □ before rolling is the tooth J.
9. It is rolled to become w2. Then, as shown in FIG. 11 (m), each tooth T□ of the first tooth group 5r-1 and each tooth T2 of the second tooth group Sl-■ taper the four corners of the teeth 4a of the workpiece. 3C in the figure
is the tooth surface of the workpiece 4 created by the tooth T□, 3d is the tooth surface of the workpiece created by the tooth 2, and 3e is the tooth T.

It shows the tooth surface of the added two objects created by.

As described above, the first and second (D
By the action of the third tooth group 5l-Q, the tooth thickness W of the teeth 4a of the workpiece 4 is sufficiently reduced from Wi to W2. , Therefore, the first wheel tooth 5I-4 and the second tooth group SI-]'
) The rolling load of each tooth on the workpiece is reduced, and the amount of bulge at the center of the tooth 4a is also suppressed, making it possible to obtain a desired crown shape. '@15 shows a perspective view of the machined tooth 4a. As is clear from this figure, each tooth surface is composed of three tooth surfaces 4b, 4C, and 4d.

The position of the third tooth group 5I-Q is as shown in FIG.
Even after the first tooth group 5I-fi and the second tooth group 5I-TI, as shown in FIG. 14 CI+, the first tooth group 5l-
1: and the second tooth group 5I-l'j, and furthermore, as shown in No. 14.4ZIOII, the first tooth group 5l
There may be two in total, one in front of -1'J and one after the second tooth group.

The processing process according to the embodiment shown in FIG. 12 is shown in FIG.
), (To explain m, first, the first tooth group SI-
(1) and the second tooth group SI-]' [to process the four corners of the tooth 4a of the workpiece into a tapered shape (Fig. Processing is performed to reduce the amount of bulge at the protrusion (FIG. 13 (II)).

In addition, Fig. 10.12, Fig. 14 rl(1:l, (m
It goes without saying that in each of the embodiments shown, the area length of each tooth group must be at least 1/2 of the pinch circumference of the workpiece 4.

Furthermore, although the embodiments shown in FIGS. 1 to 15 are all shown as finishing flat dies for finishing rough-machined workpieces, the present invention is not limited to this. , it can also be applied to flat dies for solid rolling.

Furthermore, although each of the above embodiments has been described with reference to the case of rolling a spur gear, it goes without saying that the present invention can also be applied to rolling of a helical gear.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a tooth such as a gear having a crown tooth surface, Fig. 2 is a sectional view taken along the line m-]'I in Fig. 1, and Fig. 3 is a rolling of a gear etc. having the teeth of Fig. 1. Figure 4 (T) is an explanatory diagram showing a general method for rolling gears etc. using a pair of flat dies. Figure (9) is a right side view of Figure 4 (I), Figure 5 is a plan view and side view of a flat die according to an embodiment of the first invention, and Figure 6 (Il is shown in Figure 5). An explanatory diagram showing the overlapping state of each first tooth group of a two-handed die when rolling using a pair of flat dies, FIG. 6 (5) is a diagram similar to FIG. Explanatory diagram showing the overlapping state of groups, seventh
The figure shows each tooth T□, T2 of a pair of flat dies according to the above embodiment.
FIG. 8 is a plan view of the state in which the tooth surface of the workpiece (gear) is created, and FIG. 8 shows the rolling process 1 using the flat die according to the above embodiment. FIG. 9 is an explanatory diagram showing the degree of rolling load applied to the workpiece by a pair of flat dies in the above embodiment, and FIGS. 10 to 15 are perspective views showing the teeth of the workpiece. Each embodiment of the invention is shown, and FIG. 10 is a plan view and a side view of a flat die according to one embodiment, and FIGS. 11 (I) and Q.
D is an explanatory diagram showing the process of rolling using the flat die according to the embodiment of FIG. 10, FIGS. 12 and 14 (Il, @
are plan views of flat dies according to other embodiments, and FIG. 13 (
I) , (m is an explanatory diagram showing the process of rolling with the flat die according to the embodiment of FIG. 12, and FIG. 15 1 is FIG. 8 showing the teeth of the workpiece machined by each of the above embodiments. It is a perspective view similar to SI...S-L tooth group, 5r-4...Negative) 1 tooth group, S
T-■...Second tooth group, 5l-0...Third tooth group, T,
, T2...twisted tooth, To...straight tooth, 3a,
3b... Flat die, 4... Workpiece, 4a... Teeth. Patent: 1 person: Kobe Steel Co., Ltd. Representative Patent attorney: Aoyama Aoyama and 2 others Figure 1 Figure 7 Sd Figure 8 Figure 9

Claims (1)

[Scope of claims] A flat die for crown tooth rolling, characterized in that it is composed of a second tooth group consisting of teeth having a slightly small tooth helix angle. A first tooth group consisting of teeth having a tooth trace torsion angle slightly larger than the tooth trace torsion angle, a second tooth group consisting of teeth having a tooth trace torsion angle slightly smaller than the tooth trace torsion angle of the workpiece, and a tooth trace of the workpiece. A flat die for crown tooth rolling, characterized in that it is constituted by @3 tooth groups consisting of teeth having the same tooth helix angle as the helix angle.