JPH0452042A - Plastic working device for helical gear - Google Patents

Abstract

PURPOSE:To produce a plastic working device for a helical gear capable of maintaining the cross-sectional area of stock nearly to the same value as the cross-sectional area of the final tooth form by forming a supplementary space to compensate a residual space formed in the tooth tip forming part which is not completely filled with the stock. CONSTITUTION:The supplementary space 89 to compensate the residual space formed without being filled completely with stock is formed at the tooth lip forming tart 87 of an approach tooth form 53 formed at an approach part 55 of a die 47. When the stock is extruded in the approach part 55, the stock flows in the supplementary space 89 and the cross-sectional area of the stock in the approach part 55 is always maintained nearly to the same value as the cross-sectional area of the final tooth form of the helical gear. In the complete tooth form part, the residual space is filled with the stock which flowed into the supplementary space. The supplementary space is formed by enlarging the minor diameter of the tooth fir forming tart 87 of the approach tooth form 53 in the diametrical direction. The groove bottom diameter is made larger than the tooth tip diameter of the finished tooth form. (D)

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a plastic working device for a helical gear, and in particular, a metal material is sequentially pushed into a mold by a punch, and the helical material is The present invention relates to a helical gear plastic processing device that extrudes and forms gears.

[Conventional technology]

Conventionally, as an apparatus for plastically forming a helical gear having twisted teeth by extrusion processing, for example, US Pat.
, No. 605,475 and No. 3,910,09
What is disclosed in Specification No. 1 and the like is known.

However, with such conventional equipment, lead gaps occur and the mold and material seize due to this.
There was a problem that galling occurred, and the method was not suitable for industrial mass production of helical gears.

Therefore, as a helical gear plastic processing device that solves these problems, the present applicant previously filed a patent application filed in 1983-18.
No. 0687 was filed for a helical gear plastic processing device.

This helical gear plastic processing device includes a container for external restraint into which a metal material having a center hole is inserted, a die located below the container so as to be relatively rotatable in the circumferential direction, and the container and the die. It includes a mandrel arranged on the central axis line in the die, and a punch that sequentially pushes the metal material into the gap between the mandrel, the container, and the die, and the inner wall of the die has a direction in which the material is extruded from the inner surface of the upper end thereof. An approach portion having an approach tooth profile that changes into a helical gear tooth profile as the mandrel approaches the helical gear tooth profile and a completed tooth profile portion of the helical gear tooth profile connected thereto are formed, and a metal material is expanded in diameter on the container side of the mandrel. In addition to forming an enlarged diameter part that sets the cross-sectional area necessary for helical gear forming, the substantial external shape is formed in the process in which the outer peripheral part of the material is gradually fluidly deformed into a helical gear tooth profile by the approach part, facing the approach part of the die. An inner diameter forming part is formed to reduce and deform the inner diameter of the material so that the horizontal cross-sectional area of the material remains constant even if there is a reduction amount, and further, the inner diameter of the molded product is set to the regular size in opposition to the completed tooth profile part of the die. It is formed by forming a cylindrical part.

According to this helical gear plastic working device, as shown in FIGS. 9 and 10, the mouth diameter DI and the maximum diameter portion 1 of the mandrel 15 at the mouth portion 13 of the die 11 are
The horizontal cross-sectional area of the space formed by Since the area is almost the same, the lead between the material and the die 23 is kept constant at any level from the approach section 19 to the completed tooth profile section 23, thereby preventing the occurrence of a lead gap and the resulting relationship between the die 11 and the material. It is possible to effectively prevent the occurrence of seizure, galling, etc., and also enable industrial mass production of helical gears.

In the figure, D indicates the tip diameter of the completed tooth profile, and 25 indicates a container.

[Problem to be solved by the invention]

However, in such a conventional helical gear plastic processing device, the dimensions of the die 11 and the mandrel 15 are set to be almost the same as the design values, and the gap between the mandrel 15 and the die 11 is set as a space. Even though the die 1 has the same horizontal cross-sectional area, as shown in FIG.
Approach tooth profile 27 formed on approach portion 19 of No. 1
There was a problem in that the material 31 was not completely filled into the tooth tip forming portion 29 and a residual space 33 was formed.

When the residual space 33 is formed in this way, the horizontal cross-sectional area of the material 31 decreases, that is, it extends in the axial direction, and the material 31 is finally filled in the residual space 33. However, a large amount of self-generated counter pressure is required, and in order to finally completely fill the tooth, an excessive length is required for the completed tooth profile 23 that generates the self-generated counter pressure due to frictional resistance. That will happen.

In addition, this residual space 33 is created by dividing the approach section 19 into about 10 floors at intervals of 0.5 to 1.0, for example, in order to avoid an increase in the horizontal cross-sectional area between any floors. Even if there is a 1 to 2% effective cross-section reduction rate at each level that occurs as a result of numerical processing with an effective number of 3 digits in the direction of avoidance, the material 31 is filled by the lateral stress due to the deformation resistance. The inventor has confirmed that this is not the case.

The present invention was made to solve such conventional problems, and even if a residual space occurs in the approach section,
It is an object of the present invention to provide a helical gear plastic working device that can always maintain the cross-sectional area of a material at approximately the same value as the final tooth profile cross-sectional area of the helical gear.

[Means for Solving the Problem] The helical gear plastic working device according to claim 1 comprises: a container for external restraint into which a metal material having a center hole is inserted; A rotatably arranged die, a mandrel arranged on a central axis line between the container and the die, and a punch for sequentially pushing the metal material into the gap between the mandrel, the container and the die, and the die. The inner wall is formed with an approach part having an approach tooth profile that changes into a helical gear tooth profile as it goes in the material extrusion direction from the inner surface of the upper end thereof, and a completed tooth profile part of the helical gear tooth profile connected to this, and On the container side, an enlarged diameter part is formed to expand the diameter of the metal material to set the cross-sectional area necessary for helical gear forming, and the outer periphery of the material is gradually formed into a helical gear by the approach part, facing the approach part of the die. An inner diameter forming portion is formed to reduce and deform the inner diameter of the material so that the horizontal cross-sectional area of the material remains constant even if there is a substantial amount of external reduction during the process of flow deformation into the tooth profile, and further, in the completed tooth profile portion of the die. In a plastic working device for a helical gear, which is formed by forming cylindrical portions facing each other to set the inner diameter of the molded product to a regular dimension, the tooth tip forming portion of the approach tooth profile formed in the approach portion of the die is A supplementary space is formed to compensate for the fact that the part is not completely filled with material and a residual space is formed.

In the helical gear plastic working device according to claim 2, in claim 1, the compensation space is formed by enlarging the root diameter of the tooth tip forming portion of the approach tooth profile in the radial direction, and the groove bottom diameter is equal to or smaller than the completed tooth profile. It is said to be larger than the tooth tip diameter.

According to a third aspect of the present invention, there is provided a helical gear plastic working apparatus according to the second aspect, in which the diameter difference between the groove bottom diameter and the completed tooth profile tip diameter is within 0.5 module.

In the helical gear plastic working device according to claim 4, in claim 1, the compensation space includes a tooth tip forming portion of the approach tooth profile;
It is formed by expanding in the direction of the adjacent approach tooth profile.

[For production]

In the helical gear plastic working device of claim 1, the tooth tip forming portion of the approach tooth profile formed in the approach portion of the die is not completely filled with the material and a residual space is formed. Since a compensation space has been formed to compensate for . Then, the material that has flowed into the supplementary space will fill the remaining space in the completed tooth profile.

In the helical gear plastic working device of claim 2, the compensation space is formed by radially enlarging the root diameter of the tooth tip forming portion of the approach tooth profile, and the groove bottom diameter is equal to the completed tooth tip diameter. considered to be larger.

In the helical gear plastic working apparatus of the third aspect, the diameter difference between the groove bottom diameter and the completed tooth profile tip diameter is within 0.5 module.

In the helical gear plastic working device of the present invention, the compensation space is formed by expanding the tooth tip forming portion of the approach tooth profile toward the adjacent approach tooth profile.

〔Example〕

Hereinafter, details of the present invention will be explained using the drawings.

1 and 2 show details of the die of the helical gear plastic working device shown in FIG. 3, and FIG. 3 shows an embodiment of the helical gear plastic working device of the present invention. .

In FIG. 3, reference numeral 41 indicates a container for external restraint into which a metal material 45 having a center hole 43 is inserted.

A die 47 is arranged below the container 41 so as to be rotatable relative to the container 41 in the circumferential direction.

A mandrel 49 is arranged on the central axis inside the container 41 and the die 47.

Above the container 41, there is a mandrel 49 and a container 4.
A punch 51 that sequentially pushes the metal material 45 into the gap between the metal material 1 and the die 47 is arranged.

As shown in FIGS. 1 and 2, the inner wall of the die 47 is formed with an approach portion 55 having an approach tooth profile 53 that changes into a helical gear tooth profile as the material 45 is extruded from the inner surface of the upper end thereof. has been done.

A complete tooth profile portion 57 of a helical gear tooth profile is formed in a continuous manner with this approach portion 55.

On the other hand, on the container 41 side of the mandrel 49, as shown in FIG. 3, an enlarged diameter portion 59 is formed to enlarge the diameter of the metal material 45 to set a cross-sectional area necessary for forming a helical gear.

Furthermore, even if there is a substantial reduction in the outer circumference of the material 45 at the position facing the approach portion 55 of the die 47 on the mandrel 49 during the process in which the outer peripheral portion of the material 45 is gradually fluidly deformed into a helical gear tooth profile by the approach portion 55, the material 45 is An inner diameter forming portion 61 is formed to reduce and deform the inner diameter of the material 45 so that the horizontal cross-sectional area of the material 45 becomes constant.

Further, the mandrel 49 has a completed tooth profile portion 5 of the die 47.
A cylindrical portion 63 is formed opposite to 7 to set the inner diameter of the molded product to a regular dimension.

In FIG. 3, reference numeral 65 indicates a slider, and the punch 51 is supported by the slider 65 via a holder 67 so as to be rotatable in the circumferential direction.

Further, reference numeral 69 indicates a bolster, and to this bolster 69, a pedestal 71 is fixed, and the lower ends of a plurality of guide rods 73 are fixed.

A support plate 75 is supported by the guide rod 73 so as to be vertically movable, and the support plate 75 is urged upward by a compression spring 77.

A holder 81 is fixed to the support plate 75 by a port 79, and the flange portions 83, 85 of the container 41 and the die 47 are rotatably supported by the holder 81.

Therefore, in this embodiment, FIGS. 1, 2 and 4
As shown in the figure, the tooth tip forming portion 87 of the approach tooth profile 53 formed in the approach portion 55 of the die 47 is not completely filled with the material 45, and a residual space is formed. A compensation space 89 is formed to compensate for this.

This supplementary space 89 is formed by enlarging the root diameter of the tip forming portion 87 of the approach tooth profile 53 in the radial direction, and its groove bottom diameter D0 is made larger than the tip diameter of the completed tooth profile.

In this embodiment, the difference in diameter between the groove bottom diameter D0 and the tip diameter of the completed tooth profile is 0.5 module.

In the helical gear plastic processing apparatus configured as described above, after the material 45 is accommodated between the container 41 and the mandrel 49, the slider 65 is lowered, and the punch 51 moves the material 45 to the approach portion 55 of the die 47. By extruding it forward toward the completed tooth profile portion 57, a helical gear 91 having a predetermined shape is formed.

In the helical gear plastic processing apparatus configured as described above, the horizontal cross-sectional area of the space formed by the mouth diameter of the mouth portion 93 of the die 47 and the maximum diameter portion 95 of the mandrel 49, and each of the approach portions 55 are Since the horizontal cross-sectional area formed by the approach part 55 and the inner diameter forming part 61 of the mandrel 49 in the hierarchy is almost the same as the cross-sectional area of the helical gear finally obtained, the completed tooth profile part 57 can be removed from the approach part 55. The lead between the material 45 and the die 47 is held constant in any layer including the layer, thereby effectively preventing the occurrence of a lead gap and the occurrence of burning, caulking, etc. between the die 47 and the material 45 due to this, and Industrial mass production of helical gears can be made possible.

Therefore, in the helical gear plastic working device configured as described above, the material 45 is completely attached to the tooth tip forming portion 87 of the approach tooth profile 53 formed in the approach portion 55 of the die 47. Since the compensation space 89 is formed to compensate for the residual space being formed without being filled, when the material 45 is pushed out in the approach section 55, the material A is filled in the compensation space 89 as shown in FIG. Even if a residual space B is generated in the approach portion 55, the cross-sectional area of the material 45 can always be maintained at approximately the same value as the final tooth profile cross-sectional area of the helical gear.

Then, the material A flowing into the supplementary space 89 is transferred to the completed tooth profile portion 5.
Since the remaining space B is filled in step 7, a highly accurate helical gear can be obtained.

Further, in the helical gear plastic working device configured as above, the compensation space 89 is formed by expanding the root diameter of the tooth tip forming portion 87 of the approach tooth profile 53 in the radial direction,
Moreover, since the groove bottom diameter D0 is made larger than the tip diameter of the completed tooth profile, the flow of the material 45 into the supplementary space 89 becomes smooth, and the formation of the supplementary space 89 becomes very easy.

Furthermore, in the helical gear plastic processing device configured as described above, the groove bottom diameter can be reduced. Since the difference in diameter between the tip diameter and the tip diameter of the completed tooth profile is set to 0.5 module, it is possible to effectively prevent the rigidity of the die 47 from decreasing due to the formation of the compensation space 89.

In addition, experiments have shown that about 0.5 module is sufficient for the diameter difference between the groove bottom diameter D0 and the completed tooth profile tooth tip diameter in order to balance the material A and the residual space B shown in Fig. 4. However, it has been confirmed through experiments that even if it is set larger than this, the material A will not substantially increase and no inconvenience will occur.

5 and 6 show another embodiment of the helical gear plastic working device of the present invention. In this embodiment, the groove of the tooth tip forming portion 87 of the approach tooth profile 53 forming the compensation space 89 is shown. Bottom diameter. is open and extends to the upper end surface of the die 47.

In the helical gear plastic working apparatus configured as described above, almost the same effect as in the embodiment shown in FIG. Since it is extended, it becomes possible to make the production of the die 47 very easy.

FIG. 7 shows another embodiment of the helical gear plastic working device of the present invention. In this embodiment, the groove bottom diameter D0 of the tooth tip forming portion 87 of the approach tooth profile 53 forming the compensation space 89 is , extending downward from the approach portion 55 by a certain distance.

In the helical gear plastic working apparatus constructed as described above, substantially the same effects as in the embodiment shown in FIG. 1 can be obtained.

FIG. 8 shows another embodiment of the helical gear plastic working device of the present invention. In this embodiment, the compensation space 97 extends the tip forming portion 87 of the approach tooth profile 53 to It is formed by expanding in the direction.

In the helical gear plastic working device configured as described above, almost the same effect as the embodiment shown in Fig. 1 can be obtained, but in this embodiment, it is possible to prevent the outer diameter of the die from expanding. . In the case of this embodiment, it is difficult to manufacture the die, so when manufacturing problems are taken into consideration, it is preferable to manufacture the die as in the embodiment shown in FIG.

[Effects of the Invention] As described above, in the helical gear plastic working device of claim 1, the material is completely applied to the tooth tip forming portion of the approach tooth profile formed in the approach portion of the die. We have created a compensation space to compensate for the formation of a residual space that is not filled, so when extruding the material at the approach section, the material will flow into the compensation space.
Even if a residual space occurs in the approach portion, the cross-sectional area of the material can always be maintained at approximately the same value as the final tooth profile cross-sectional area of the helical gear.

Then, the material that has flowed into the supplementary space fills the remaining space in the completed tooth profile, so that a highly accurate helical gear can be obtained.

In the helical gear plastic processing apparatus according to claim 2, the compensation space is formed by expanding the root diameter of the tip forming portion of the approach tooth profile in the radial direction, and the groove bottom diameter is set to be equal to the tip diameter of the completed tooth profile. Since it is made larger, the material flows smoothly into the filling space, and the filling space can be formed very easily.

In the helical gear plastic processing apparatus of claim 3, the diameter difference between the groove bottom diameter and the completed tooth profile tip diameter is set within 0.5 modules, so that the decrease in die rigidity due to the formation of the compensation space can be effectively avoided. It can be prevented.

In the helical gear plastic processing apparatus according to claim 4, the compensation space is formed by expanding the tooth tip forming portion of the approach tooth profile in the direction of the adjacent approach tooth profile.
This has the advantage that the outer diameter of the die can be prevented from expanding.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing details of the die of FIG. 3. FIG. 2 is a top view showing details of the die of FIG. 1; FIG. FIG. 3 is a longitudinal sectional view showing an embodiment of the helical gear plastic working apparatus of the present invention. FIG. 4 is an explanatory diagram for explaining details of the supplementary space formed in the die. FIG. 5 is a longitudinal sectional view showing a die of another embodiment of the helical gear plastic working apparatus of the present invention. FIG. 6 is a top view of the die of FIG. 5. FIG. 7 is a longitudinal sectional view showing a die of still another embodiment of the helical gear plastic working apparatus of the present invention. FIG. 8 is an explanatory view showing a die of still another embodiment of the helical gear plastic working apparatus of the present invention. FIG. 9 is a longitudinal sectional view showing a die and mandrel of a conventional helical gear plastic working device. FIG. 10 is a top view of FIG. 9. FIG. 11 is an explanatory diagram for explaining details of the remaining space formed in the die. [Explanation of symbols of main parts] 41...Container 45...Material 47...Die 49...Mandrel 51...Punch 53...Approach tooth profile 55...Approach part/completed tooth profile part - Expanded diameter part, inner diameter forming part, cylinder part, tooth tip forming part, compensation space. Figure Figure Figure Figure

Claims (4)

[Claims] (1) A container for external restraint into which a metal material having a center hole is inserted, a die located below this container so as to be relatively rotatable in the circumferential direction, and a center axis line between the container and the die. a mandrel disposed in the die, and a punch for sequentially pushing the metal material into the gap between the mandrel, the container, and the die;
An approach part having an approach tooth profile that changes into a helical gear tooth profile in the material extrusion direction from the inner surface of the upper end thereof and a completed tooth profile part of the helical gear tooth profile connected thereto are formed, and the container side of the mandrel is , the diameter of the metal material is expanded to form an enlarged diameter part that sets the cross-sectional area necessary for forming a helical gear, and the outer peripheral part of the material is gradually deformed into a helical gear tooth shape by the approach part, facing the approach part of the die. An inner diameter forming part is formed to reduce and deform the inner diameter of the material so that the horizontal cross-sectional area of the material remains constant even if there is a substantial reduction in the external shape during the process of forming the material, and further forming the inner diameter part opposite to the completed tooth profile part of the die. In a plastic working device for a helical gear formed with a cylindrical part that sets the inner diameter of the product to a regular dimension, a material is applied to the tip forming part of the approach tooth profile formed in the approach part of the die. A helical gear plastic processing device characterized in that a compensation space is formed to compensate for a residual space that is not completely filled. (2) The compensation space is formed by radially enlarging the root diameter of the tooth tip forming portion of the approach tooth profile, and the groove bottom diameter is larger than the completed tooth tip diameter. The helical gear plastic working device according to claim 1. (3) The helical gear plastic working device according to claim 2, wherein the diameter difference between the groove bottom diameter and the completed tooth profile tip diameter is within 0.5 module. (4) The helical gear plastic working device according to claim 1, wherein the compensation space is formed by expanding the tooth tip forming portion of the approach tooth profile toward the adjacent approach tooth profile.