JPH10156466A - Gear punching die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear punching die advantageous to improve the precision of a punched gear, particularly the tip part thereof. SOLUTION: This gear punching die 1 is provided with a dedendum forming part 11 to form the dedendum part of the punched gear and a tip forming part 12 to form the addendum part of the punched gear. In the gear punching die, many grooves 2 for discharging material are formed on a side face facing an opposite die. An inclination for a horizontal line of inclined faces 21, 22 constituting the groove 2 is set unsymmetrical in the direction to increase a cross sectional area of a groove passage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gear punching die. The present invention is applicable to, for example, punching of helical gears, spur gears, and the like.

[0002]

2. Description of the Related Art A gear punching type of a helical gear having a helical tooth portion will be described as an example. FIG. 5 shows a main portion of a plan view of the gear punching die 300, and FIG. 6 shows a cross section of the gear punching die 300. As can be understood from FIG. 5 and FIG.
00 is a stamping cavity 313 having a tooth base forming part 311 forming a gear tooth root part and a tooth tip forming part 312 forming a tooth tip part of a gear, and an end face of a projection facing the mating mold, And a groove 302 for discharging the material formed on the upper surface.

[0003] The root forming portion 311 and the tooth tip forming portion 312 are helical. The groove 302 is formed in the root forming portion 311.
Are extended in the radial direction from the end face in the radial direction. FIGS. 8A to 8C show the usage of the gear punching die 300.
It is shown in (C). In this use mode, FIGS. 8 (A) to 8 (C)
As shown in the figure, the gear punching die 300 is disposed as a fixed die on the lower side, the breakout punch 410 is fitted in the punching cavity 313 of the gear punching die 300, and the flat die 414 fitted with the ejector punch 412 is further provided. The gear punch 3
It is located above 00.

The breakout punch 410 and the ejector punch 412 have helical external teeth-shaped projections. The flat die 414 has a helical internal tooth-shaped protrusion. According to the above-described technology, in performing the gear punching process, first, a cutting process is performed. That is, as can be understood from FIG. 8A, the flat die 414 is lowered together with the ejector punch 412 while rotating the flat die 414 about the central axis P1.
Make a cut in the outer peripheral edge of. The notch has a function of promoting punching, which is a subsequent step. FIG. 7B shows the completion of the cutting.

Next, a punching step is performed. That is, FIG.
As can be understood from (C), while making the gear punching die 300 function as a fixed die, the breakout punch 410 is raised while rotating about the central axis P1, and the punching of the cut portion of the outer peripheral edge of the metal material W is performed. Complete. As a result, the helical gear is stamped. According to this method, the breakout punch 410 and the ejector punch 4
Since the disk-shaped metal material W is compressed by being sandwiched between the metal material W and the metal material 12, the metal material W is shear-separated in a compressed state, and precise punching is realized.

As can be understood from FIGS. 8 (B) and 8 (C), the excess thickness Wa of the outer edge of the metal material W flows radially outward along the groove 302 of the gear punching die 300. Thereby, the tooth portion of the punched gear is formed well. FIG. 7 shows a state where a cross section along the pitch circle diameter Rc of the gear punching die 300 in the cutting step is developed. As can be understood from FIG. 7, the groove 302 is constituted by slopes 320 and 321 facing each other. The slopes of the slopes 320 and 321 are set symmetrically. That is, as can be understood from FIG.
And the slope angle θ1 of the slope 321 with respect to the horizontal line H is set to be equal. The valley bottom line that functions as the intersection line between the slope 320 and the slope 321 is shown as 323 in FIGS.

[0007]

By the way, there is an increasing demand in the industry for high quality punched gears. Therefore, in recent years, there has been an increasing demand for higher precision punched gears. However, the tip of the punched gear is liable to be sagged, and there is a limit in improving the accuracy of the tip of the punched gear. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a gear punching die that is advantageous for improving the accuracy of a stamped gear, particularly the accuracy of the tooth tip of the stamped gear.

[0008]

SUMMARY OF THE INVENTION The present inventor has proceeded with the development based on the above-mentioned problems, and the slopes of the slopes 320 and 321 constituting the above-mentioned material discharge groove 302 are increased by increasing the groove passage cross-sectional area. If the orientation is set to be asymmetrical to each other, it has been found that it is advantageous to improve the accuracy of the tooth tip portion by suppressing the sagging of the tooth tip portion of the punched gear, and confirmed by a test, and confirmed the present invention. completed.

The reason why the sagging of the tooth tip of the punched gear can be suppressed is presumed as follows. In other words, when the radially outward radius of the flesh material increases, the flesh portion forming the tooth tip of the punched gear tends to excessively radially outwardly flow under the influence of the influence. In this case, it tends to be a cause of sagging of the tooth tip of the punched gear. However, in the present invention, the metal material W
The radially outward flow of the outer peripheral edge portion of the punched gear can be suppressed, and the radially outwardly flowing radius can be suppressed. It is presumed that it is possible to suppress excessive outflow.

That is, a gear punching die according to the present invention comprises a punching cavity having a tooth root forming part forming a tooth root of a gear and a tooth tip forming part forming a tooth tip of a gear, and a mating die. In a gear punching die having a material discharge groove formed on the end face on the facing side and extending radially outward from the end face of the tooth base forming portion, the groove is constituted by slopes facing each other, and the slope of the slope is It is characterized in that the groove passages are set to be asymmetrical with each other in a direction to increase the cross-sectional area.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS This embodiment will be described. This embodiment is applied to an example in which a helical gear is punched by the method shown in FIGS. 8A to 8C, which is also called a facing die shearing method. Also in the present embodiment, the cutting step and the punching step are performed in the same manner as in the conventional technique shown in FIGS. 8A to 8C described above.

FIG. 1 is a plan view showing a main part of the gear punching die 1. FIG. 2 shows a sectional view of the gear punching die 1. The gear punching die 1 functions as a fixed die, and has a tooth root forming part 11 forming a tooth root part of a punched gear and a tooth root forming part 12 forming a tooth tip part of a punched gear. A cavity 13 is provided. The tooth base forming part 11 and the tooth tip forming part 12 are formed in a helical shape.

The end face of the gear punching die 1 on the side facing the flat die 414 which is the mating die, that is, the upper surface 1x
Are formed with a number of grooves 2 for discharging material. Groove 2
Is extended radially outward from the tooth base forming portion 11. The inner end 2a of the groove 2 faces the punching cavity 13, and
The outer end 2c of the groove 2 is oriented away from the punching cavity 13 and counterclockwise as can be seen from FIG. The turning direction of the flat die 414 is indicated by an arrow M.
1 is shown in FIG.

FIG. 3 shows a state in which a cross section along the pitch circle diameter Rc of the gear punching die 1 in the cutting step is developed. As can be understood from FIG. 3, the groove 2 is constituted by slopes 21 and 22 facing each other. The slopes of the slopes 21 and 22 forming the groove 2 are set to be asymmetrical with each other in a direction to increase the groove passage cross-sectional area. By the way, FIG.
(C) shows a mode in which the slopes of the slopes 21 and 22 of the groove 2 are changed. FIG. 4A shows a method in which the slope angle θ1 of the slope 21 and the slope angle θ2 of the slope 22 are symmetrical to each other. FIG.
The method shown in (A) corresponds to the conventional technique shown in FIGS. 5 to 7. In this conventional technique, θ1 and θ2 are symmetrical with respect to the horizontal line H in the range of 40 to 50 °. Is set.

In order to make the slopes 21 and 22 of the groove 2 asymmetrical, as shown in FIG.
If the other slope 22 is made closer to the horizontal while maintaining the slope of the slope 2, the slope 21 is oriented in a direction to reduce the groove passage cross-sectional area of the groove 2.
And the gradient angle θ2 of the slope 22 can be asymmetrical to each other. Further, as shown in FIG.
If the other slope 22 is made closer to the vertical while maintaining the slope of 1, the slope angle θ1 of the slope 21 and the slope angle θ2 of the slope 22 are asymmetrically set in a direction to increase the groove passage cross-sectional area of the groove 2. it can.

In the present embodiment, the latter method shown in FIG. 4C is employed instead of the former method shown in FIG. This is the first feature of the present embodiment.
Specifically, the slope angle θ1 of the slope 21 is set in a range of 40 to 50 ° with respect to the horizontal line H. Other slopes 22
Is set in the range of 75 to 85 ° with respect to the horizontal line H. As a result, assuming that the groove passage cross-sectional area of the groove 2 according to FIG. 4 (C) is SA and the groove passage cross-sectional area of the groove 2 according to the prior art is SB, SA increases from SB and SB
About twice.

In other words, the groove passage cross-sectional area of the groove 2 according to this embodiment is greatly increased. In the present embodiment as described above, it is possible to suppress the outflow radius at which the excess thickness Wa flows outward in the radial direction while securing the amount of the excess thickness Wa of the metal material W flowing outward in the radial direction. Further, a valley bottom line functioning as an intersection line between the slope 21 and the slope 22 constituting the groove 2 is shown as 23. The angle of the valley bottom line 23 with respect to the horizontal line H is 2
The angle is set to a range of 5 to 35 ° and the angle (15 to 15) of the valley bottom line 323 according to the related art shown in FIG.
(20 °). This is the second feature of the present embodiment. Therefore, also in this sense, in the present embodiment, the outflow radius at which the excess thickness Wa flows outward in the radial direction can be suppressed while maintaining the amount of excess thickness Wa of the metal material W flowing outward in the radial direction.

As described above, in the present embodiment, the first feature described above allows the excess thickness Wa of the metal material W to be maintained in the radially outward direction while maintaining the excess thickness Wa in the radially outward direction. The outflow radius flowing out to the can be suppressed. Therefore, it is advantageous to suppress the flesh material near the tooth tip forming portion 12 of the metal material W to be a punched gear from flowing out radially outward. Therefore, it is advantageous for suppressing flaking at the tooth tip of the punched gear. Therefore, the accuracy at the tooth tip of the punched gear is improved, which is advantageous for obtaining a highly accurate punched gear.

Furthermore, in the present embodiment, the outflow radius at which the metal material W flows outward in the radial direction can also be suppressed by the above-described second feature. This is advantageous for suppressing the excessive flow of the flesh material outward in the radial direction, and is more advantageous for suppressing flaking at the tooth tip of the punched gear. Therefore, it is more advantageous to obtain a high precision punched gear.

In addition, in the present embodiment, as described above, since the excess radius of the excess thickness Wa of the metal material W flows outward in the radial direction, the outflow radius can be suppressed, so that a reduction in friction at the time of outflow can be expected. Therefore, even if the cutting depth to the metal material W in the cutting step is increased, it is advantageous in suppressing an increase in the cutting load. Therefore, in the cutting step, it is advantageous to increase the cutting depth in the metal material W.

If the depth of cut into the metal material W can be increased as described above, it is advantageous to suppress a punching load in a punching step performed after the cutting step. Furthermore, in the present embodiment, as described above, the excess material W of the metal material W is used.
Since the outflow radius at which a flows out in the radial direction can be suppressed, it is advantageous to reduce the outer diameter size of the metal material W while suppressing the sagging of the punched gear, and an improvement in the material yield can be expected.

Further, this embodiment has the following third feature.
That is, as shown in FIG. 1, a tooth tip projection 5 is provided on the upper surface of the gear punching die 1. The tooth tip projections 5 are arranged near each of the tooth tip forming portions 12 of the punching cavity 13. In the manufacturing process of the punched gear, the tooth tip projection 5 tends to locally press the metal material W immediately before punching. Therefore, immediately before the punching, the internal pressure of the material portion of the metal material W near the tooth tip forming portion 12 is likely to be locally higher than the internal pressure of the material portion of the other region. As a result, in the punching process, it is advantageous to satisfactorily punch out the tooth tip portion of the punched gear in which an abnormal fracture surface is likely to occur, which can further contribute to high precision of the tooth tip portion of the punched gear.

[0023]

According to the gear punching die according to the present invention, a punching cavity having a tooth tip forming portion and a punching cavity formed on an end face facing the mating die in a radially outward direction from the end face of the tooth root forming portion. The groove has an extended material discharging groove, and the groove is formed of slopes facing each other, and the slopes are set to be asymmetric with respect to each other in a direction to increase a groove passage cross-sectional area.

[0024] Therefore, according to the gear punching die according to the present invention, in the manufacturing process of the punched gear, the excess thickness of the metal material flows out in the radial direction while securing the outflow amount flowing out in the radial direction. This is advantageous for suppressing the outflow radius. As described above, according to the gear punching die according to the present invention, the excess thickness of the tooth root portion is caused to flow radially outward through the groove having a large groove passage cross-sectional area. The outflow radius flowing out can be suppressed. Therefore, it is advantageous to prevent the flesh material near the tooth tip forming portion from flowing excessively outward in the radial direction. Therefore, it is advantageous to suppress the sagging of the tooth tip of the punched gear. Therefore, it is possible to contribute to higher precision of the punched gear, particularly higher precision of the tooth tip.

Further, according to the gear punching die of the present invention, when the tooth tip projections are arranged in the vicinity of the tooth tip forming portions of the punching cavity, the metal blank is formed in the process of manufacturing the punched gear. The tooth tip protrusion is likely to be locally overpressed. Therefore, among metal materials, the internal pressure of the material portion near the tooth tip forming portion tends to be locally higher than the internal pressure of the material portion in other regions. As a result, it is advantageous to satisfactorily punch out the tooth tip portion of the punched gear in which an abnormal fracture surface is likely to occur, and can further contribute to high precision of the tooth tip portion of the punched gear.

[Brief description of the drawings]

FIG. 1 is a plan view showing a main part of a gear punching die.

FIG. 2 is a sectional view of a gear punching die.

FIG. 3 is a configuration diagram showing a state of development along a pitch circle diameter in a cutting step.

FIG. 4 is a cross-sectional view showing a form in which a slope of a slope forming a groove is changed.

FIG. 5 is a plan view showing a main part of a gear punching die according to the prior art.

FIG. 6 is a sectional view of a gear punching die according to the prior art.

FIG. 7 is a configuration diagram showing a state of being developed along a pitch circle diameter in a cutting step according to a conventional technique.

FIG. 8 is a process diagram showing a punching process according to a conventional technique.

[Explanation of symbols]

In the figure, 1 is a gear punching die, 11 is a tooth base forming portion, 12 is a tooth tip forming portion, 13 is a punching cavity, 2 is a groove, 20 and 21.
Indicates a slope, and 23 indicates a valley bottom line.

Claims (1)

[Claims] 1. A punching cavity having a root portion forming a root portion of a gear and a root portion forming a tip portion of a gear, and a punching cavity formed on an end surface facing a mating die. In a gear punching die having a material discharge groove extending radially outward from a tooth base forming portion, the groove is configured by slopes facing each other, and the slope of the slope is a direction to increase a groove passage cross-sectional area. A gear punching type characterized by being set asymmetrically with each other.