JPS60257920A - Method and device for extrusion molding of helical gear - Google Patents

Abstract

PURPOSE:To produce efficiently a helical gear by continuous extrusion molding at a good yield by inserting a cylindrical blank material into a die having internal helical teeth and pressurizing the material by a sleeve punch having concentrically a spline-shaped mandrel. CONSTITUTION:Another cylindrical blank material 31 is inserted into the die 22 having the internal helical teeth 22a while the cylindrical blank material 30 formed with the helical teeth 30a to the mid-way is held inserted therein. The formation of the helical teeth 30a of the lower material 30 progresses when the mandrel 28 having the spline-shaped outside circumference and the sleeve punch 26 are lowered. The material 30 rotates during this formation and the mandrel 28 is rotated via the splines 30b, 28d until the formation of the teeth 30a ends, when the helical gear 30 is extruded to the outside of the die 22. The helical teeth 31a are formed at the same time on the outside circumference of the upper material 31. The continuous production of the helical gear is made possible by the above-mentioned method without requiring machining.

Description

Detailed Description of the Invention (Industrial Field of Application) This invention is used as gears for automobiles and various mechanical devices, and in particular, it is a method for forming helical gears that have a helical ring on the outer periphery and a spline on the inner periphery. The present invention relates to a helical gear extrusion molding method and an extrusion molding apparatus suitable for this purpose.

Examples of the extrusion molding apparatus used in the conventional extrusion molding method for helical gears include those shown in FIGS. 1 and 2. In FIGS. 1 and 2, 1 is a base plate having an opening 1a, 2 is a gooey disposed on the base plate 1 and has an internal helical helix 2a on the inner periphery, and 3 is an upper part of the gooey 2. and the guide hole 3a
The die 2 and the container 3 are fixed to the base plate 1 via the reinforcing ring 4 in a state where the die 2 and the container 3 are burnt out or press-fitted into the reinforcing ring 4.

On the other hand, 5 is an upper plate that can be raised and lowered, 6 is an annular sleeve punch fixedly held on the upper plate 5 by a fixing plate 7, and 8 is the sleeve punch 6.
This is a mandrel that is inserted and fixed inside.

Next, to explain the movement of the forming apparatus having the above-mentioned configuration, in the shape M shown in FIG. There is a cylindrical material 10 on which another cylindrical material 11 is placed.
After charging, the mandrel 8 and sleeve punch 6 are lowered. In this state, when the mandrel 8 and the sleeve punch 6 are further lowered, the formation of the helical helical 10a of the lower cylindrical material 10 progresses, and after the formation of the helical 10a is completely completed, the shape shown in FIG. As shown in FIG. 2, the upper cylindrical material 11 is extruded out of the die 2, and at the same time a helical part 11a is formed on the outer periphery of the upper cylindrical material 11.
After extrusion of the cylindrical material 11, the cylindrical material 11 is formed to the same extent as the cylindrical material 10 shown in FIG. After forming, the sleeve punch 6 with the mandrel 8 is moved up to a position higher than the container 3, and after charging the next cylindrical material into the container 3, the mandrel 8 and sleeve punch 6 are lowered again to Pressure mold a cylindrical material. By sequentially repeating the above steps, a helical gear having a hole in the center through which the shaft passes is continuously formed.

However, in such a conventional extrusion molding apparatus, the cross-sectional shape of the mandrel 8 shown in FIG. 1 was a perfect circle as shown in FIG. 12a and a straight shaft through hole 12b on the inner periphery, it is possible to form a helical gear 12, but as shown in FIG. It is difficult to mold the helical gear 13 having the spline 13b, and when molding the helical gear 13 having the spline 13b, the molding device shown in FIG. Helical gear shown 1
After molding 2, it was necessary to take a step of machining splines on the inner circumference. In addition, in the extrusion molding apparatus described above, the mandrel 8 was fixed by the sleeve punch 6 and could not rotate freely. The material 10.11 rotates along the inner tooth helix 2a of the die 2, but the mandrel 8 is difficult to rotate. Therefore, it is not possible to simply provide a spline around the outer periphery of the mandrel 8 using conventional molding equipment. However, there was a problem in that it was difficult to form splines on the inner periphery of the cylindrical materials 10 and 11.

(Object of the Invention) The present invention was made by focusing on such conventional problems, and it is possible to continuously produce a helical gear having a helical gear on the outer periphery and a spline on the inner periphery by extrusion molding. It is an object of the present invention to provide an extrusion molding method and an extrusion molding apparatus for helical gears that can be molded.

(Structure of the Invention) When molding a helical gear having a helical ring on the outer periphery and a spline on the inner periphery, the present invention charges a cylindrical material into a die having a helical inner tooth, Pressure is applied to the cylindrical material using a sleeve punch having substantially concentric mandrels whose outer periphery has a spline shape, and the mandrel forms a spline on the inner periphery of the cylindrical material, and the inner teeth are formed into a spline shape to form a spline on the cylindrical material. The extrusion molding device directly used for carrying out this method includes a die having internal teeth and a spline-shaped outer periphery. a mandrel that forms a spline on the inner circumference of the cylindrical material charged into the die, and a mandrel that fits concentrically with the mandrel and presses the cylindrical material to form a spline on the outer periphery of the cylindrical material. and a sleeve punch for forming the cylindrical material, the mandrel is rotatable within the sleeve punch when the cylindrical material is press-formed by the mandrel and the sleeve punch, and the mandrel is not rotatable except for compression molding. It is characterized in that it is provided with an engaging portion.

(Embodiment) FIGS. 6 to 12 are diagrams showing an embodiment of the present invention. First, in FIGS. 6 and 7, 21 is a base plate having an opening 21a, 22 is a die disposed on the base plate 21 and has an internal helical helix 22a on the inner periphery, and 23 is the die 22. The container is disposed at the upper part and has a guide hole 23a, and the die 22 and the container 23 are burned out or press-fitted into a reinforcing ring 24, and the base plate 1 is inserted through the reinforcing ring 24.
- Fixed to 21.

On the other hand, 25 is an upper plate that can be raised and lowered, 26 is an annular sleeve punch fixedly held on the upper plate 25 by a fixing plate 27, and 28 is fitted in the sleeve punch 26 so as to be slidable in the vertical and rotational directions. It is an inserted mandrel.

Here, the upper end portion of the mandrel 28 is formed with a tapered portion 28a having an inclination angle α whose diameter increases upward, and a large diameter portion 28b continuing from the tapered portion 28a.
The upper end face is formed into a spherical part 28c, and comes into contact with the upper plate 25 at its apex. Further, the upper end portion of the sleeve punch 26 includes a tapered portion 26a having approximately the same inclination angle as the tapered portion 28a of the mandrel 28, and an inner diameter portion 26b that is slightly larger than the large diameter portion 28b of the mandrel 28. When the spherical portion 28c of the mandrel 28 is in contact with the upper plate 25, a gap C (see also FIG. 11) is formed between the tapered portions 26a and 28L.

Further, a spline 28d as shown in FIGS. 8(a) and 8(b) is formed at the lower end portion of the mandrel 28 and at the portion exposed from the sleeve punch 26. Further, the lower end portion of the spline 28d is formed at an angle β as shown in FIG. 9. Next, the operation of the helical gear extrusion molding apparatus having the above-described structure will be explained.

First, in the state shown in FIG. 6, there is a cylindrical material 30 in which a helical helix 30a is formed halfway by the internal tooth helical 22a that forms the helical, and another cylindrical material 3 is placed on top of it.
1, the mandrel 28 and sleeve punch 26 are lowered. In such a state, the spherical portion 28c of the mandrel 28, as shown in FIG.
It is in contact with the upper plate 25 and the mandrel 28
The tapered portion 28a of the sleeve punch 26 and the tapered portion 26 of the sleeve punch 26
Since the gap C is formed between the sleeve punch 26 and the sleeve punch 26, the mandrel 28 can rotate within the sleeve punch 26.

When the mandrel 28 and the sleeve punch 26 are further lowered in this state, the forming of the helical part 30a of the lower cylindrical material 30 progresses, and the cylindrical material 30 rotates when forming the helical part 30a. , spline 3
The mandrel 28 also rotates via 0b and 28d. After the helical gear 30a is completely formed, the helical gear 30 is pushed out of the die 22 as shown in FIG. After the helical helical 31a is formed and the cylindrical material 30 is extruded, the cylindrical material 31 is also formed to the same extent as the cylindrical material 30 shown in FIG.

After the molding is completed, the mandrel 28 and sleeve punch 26
When raising the cylindrical material 31, a helical helical 31a is partially formed on the lower outer periphery of the cylindrical material 31, and the internal tooth helical 22
a, the cylindrical material 31 remains in the same position without moving upward, and the mandrel 28 is pulled out from the cylindrical material 31 little by little. In this state, as shown in FIG. 10, the tapered portion 28a of the mandrel 28 and the tapered portion 26a of the sleeve punch 26 fit together at a small taper angle α (for example, 20 degrees or less), and this fitting As a result, a retaining portion between the mandrel 28 and the sleeve punch 26 is formed, so that the mandrel 28 cannot rotate relative to the sleeve punch 26. In this state, the lower end of the mandrel 28 is raised to a position higher than the container 23.

Next, as shown in FIG. 6, the die 22 is removed from the container 23.
Another cylindrical blank 31 is inserted into the chamber and placed on top of the cylindrical blank 30 which has already been partially helical shaped. Subsequently, the mandrel 28 and the sleeve punch 26 are lowered into the container 23, but at this time, the mandrel 28 is also lowered by its own weight into the sleeve punch 26 as shown in FIG. 1O.
The taper portion 26a128a remains fitted within the mandrel 28, and the mandrel 28 cannot be easily rotated. As shown in FIG. 6, since the inner diameter of the charged cylindrical material 31 is slightly larger than the outer diameter of the spline 28d of the mandrel 28, the mandrel 28 does not rotate and the cylindrical material 31 is rotated. Moving down the inner diameter part, the spline 28d of the mandrel 28 fits into a spline formed on the inner diameter part of the cylindrical material 30 that is currently being formed. During this fitting, the shape of the lower end 28, e of the spline 28d of the mandrel 28 is tapered as shown in FIG.
is a spline 30 of a cylindrical material 30 that is being smoothly formed.
Can be fitted to b. Here, as shown in FIG. 12, if the mandrel 28 descends without the crests of the splines 28d of the mandrel 28 and the splines 30d of the cylindrical material 30 in the process of being formed being aligned, the state shown in FIG. 9(b) occurs. As shown, the lower end 28e of the spline 28d of the mandrel 28
A spline 3 of a cylindrical material 30 that is being formed in the taper part of
The mountain of 0d hits. At this time, the mandrel 28 is
Tapered portion 26a shown in the figure.

The tapered portion 26a shown in FIG. 11 from the state in which 28a is in close contact with
, 28 & to be separated, the mandrel 28 rotates along the tapered portion of the lower end 28e of the spline 28d, and as shown in FIG. It can be smoothly fitted into the spline 30d without damage.

After that, the sleeve punch 26 and the mandrel 2
8 descends and the forming of the cylindrical material 30, 31 progresses, a dowel begins to be formed on the outer periphery of the cylindrical material 31. The cylindrical materials 30 and 31 rotate along the internal teeth of the die 22 and the helical helical 22a while the helical helical parts 30a and 31& are being formed. Since the mandrel 28 is fitted with a spline formed on the inner diameter of the cylindrical material 30, it rotates together with the material 30. At this time, mandrel 28
Since there is a gap C between the sleeve punch 26 and the sleeve punch 26 as shown in FIG. This makes it possible to prevent the spline 30a on the inner diameter portion of the cylindrical material 30 from being damaged.

After that, a sleeve punch 26 and a mandrel 28
When the cylindrical material 31 is lowered, a dowel begins to be formed on the outer periphery of the cylindrical material 31 shown in FIG. Since the material is restrained by the punch 26, the material flows into the gap between the inner diameter part of the cylindrical material 31 and the spline 28d of the mandrel 28, and
As the molding of the dowels progresses on the outer periphery of the cylindrical material 30, the material fills the gap, and as a result, the cylindrical material 30 extruded from the die 22 has a heel 30a,
A spline 30b is formed at the same time on the inner periphery.

Here, the reason why the mandrel 28 is made unrotatable relative to the sleeve punch 26 except for press molding is to prevent the spline 31d, which is partially formed in advance on the cylindrical material 31, from being deformed by the rotating mandrel 28. It's for a reason.

(Effects of the Invention) As described above, according to the present invention, when molding a helical gear having a helical ring on the outer periphery and a spline on the inner periphery, the internal teeth are formed in a die having a helical ring. A cylindrical material is charged into the cylindrical material, and the cylindrical material is pressurized using a sleeve punch having approximately concentric mandrels whose outer periphery has a spline shape, and a spline is formed on the inner periphery of the cylindrical material by the mandrel. The inner tooth is formed with a dowel on the outer periphery of the cylindrical material, and in an apparatus for carrying out this method, the inner tooth has a gou having the dowel and the outer circumference has a spline shape. A mandrel that forms a spline on the inner periphery of the cylindrical material charged into the gou is fitted concentrically with the mandrel and presses the cylindrical material to form a spline on the outer periphery of the cylindrical material. a sleeve punch for forming the cylindrical material, the mandrel is rotatable within the sleeve punch when the cylindrical material is press-formed by the mandrel and the sleeve punch, and the mandrel is not rotatable except for press-forming. Because of the structure in which an engaging part is provided, it is possible to extrude the dowel on the outer periphery of the cylindrical material and the spline on the inner periphery at the same time.Since no cutting is involved, the yield is high and productivity is high. A very excellent effect can be obtained that is excellent in both.

[Brief explanation of the drawing]

Figures 1 and 2 are longitudinal sectional views of the main parts of a conventional helical gear extrusion molding device at different points in its movement, and Figure 3 (a)
(b) is a side view and a horizontal cross-sectional view showing the tip shape of the mandrel used in a conventional helical gear extrusion molding device, and FIG. 4 is a cross-sectional view of a helical gear molded by a conventional extrusion molding device. FIG. 5 is a cross-sectional view of a helical gear molded by the helical gear extrusion molding device according to the present invention, and FIGS. 6 and 7 show the movement of the helical gear extrusion molding device in one embodiment of the present invention. Longitudinal cross-sectional views of main parts at different times, FIG. 8(a)
(b) is a side view and horizontal sectional view showing an example of the shape of the mandrel of the device shown in FIG. 6, and FIGS. 9(a) and (b)
(c) is a partial side view, a sectional view taken along the line A-A, a partial perspective view, and a partial perspective view showing the spline shape of the tip of the mandrel;
0 and 11 are cross-sectional explanatory views showing the positional relationship between the mandrel and the sleeve punch in the apparatus shown in FIG. 6, and FIGS. 12(a), (b), and (c) are spline forming parts of a cylindrical material. FIG. 2 is an explanatory view showing how the splines of the mandrel are fitted. 13... Helical gear. 13a...Hasuba, 13b...Spline, 22...Gui, 2211L...Internal tooth helical, 26...Sleeve punch, 2611L...Tapered part (retaining part) of sleeve punch ), 28... Mandrel, 28a... Taper part (retaining part) of mandrel, 28
d... Spline, 30.31... Cylindrical material. Patent Applicant Nissan Motor Co., Ltd. Representative Patent Attorney Yutaka Shio 3I! I Figure 8 (a) (a)

Claims (2)

[Claims] (1) When molding a helical gear that has a helical ring on the outer periphery and a spline on the inner periphery, a cylindrical material is charged into a gou having a helical tooth on the inner tooth, and the outer periphery forms a spline shape. The cylindrical material is pressurized using a sleeve punch having mandrels substantially concentric, and the mandrel forms a spline on the inner periphery of the cylindrical material, and the inner teeth form a spline on the outer periphery of the cylindrical material. A method for extruding helical gears, characterized by forming a helical gear. (2) A gooey having internal teeth with a helical ring, and a mandrel having a spline-shaped outer periphery and forming a spline on the inner circumference of a cylindrical material inserted into the goo are fitted concentrically with the mandrel. and a sleeve punch that presses the cylindrical material to form a slot on the outer periphery of the cylindrical material, and when the cylindrical material is pressed by the mandrel and sleeve punch, the mandrel is inserted into the sleeve punch. 1. An extrusion molding device for a helical gear, characterized in that it is provided with an engaging portion that makes the mandrel rotatable except during compression molding.