JPH0566220B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a helical gear plastic working device, and more specifically, the present invention relates to a plastic working device for a helical gear, and more specifically, a material processed into a single product is sequentially pushed into a mold by a punch, The present invention relates to a plastic processing device that extrudes a helical gear by passing through a mold twice.

[Conventional technology]

Conventionally, a device for plastically forming helical gears with helical teeth by extrusion was disclosed in U.S. Patent No.
It is known from specifications such as No. 3605475 and No. 3910091.

Such a helical gear extrusion processing device includes a die having helical gear teeth on the inner wall surface, a container integrated with the die, a mandrel arranged on the axis of the die and the container, and a metal material inside the container and the die. It consists of a combination of a punch that pushes in and extrudes the helical gear.

[Problems to be solved by the invention] In the conventional helical gear extrusion processing device as described above, relative rotation in the circumferential direction between the mandrel and the die is possible, but the die and the container are integrated. Since the metal material being pushed into the die and the die are unable to rotate relative to each other in the circumferential direction, when the metal material is pushed into the die to form twisted teeth on the outer peripheral surface of the metal material, the material Flow (elongation) in the axial direction occurs, which acts to form a product tooth with a helix angle smaller than the helix angle of the die tooth, and creates a lead gap between the die tooth and the material tooth that is being formed. occurs. As a result, a large stress is generated on one side of each tooth between the die and the material, which causes a pressure difference on the left and right sides of the molded product tooth, including elastic return, against the die tooth. In addition to causing seizure or galling of the parts, there was also the problem that, in the worst case, the die teeth could be damaged.

In addition, in the above-mentioned US Patent No. 3,605,475, in order to prevent the metal material from elongating in the axial direction during extrusion processing, the hollow part of the material is left in an unrestrained state without using a mandrel, and the material is allowed to flow toward the inner diameter of the material. A method that allows for flow is adopted.

Although this method has the effect of reducing the lead gap, the three-dimensional restraining force from the inner and outer peripheral surfaces of the material and the axial direction during flow deformation decreases, making it impossible to obtain highly accurate helical teeth. There was a problem in that the accuracy of the inner diameter dimension also decreased.

Therefore, although plastic processing technology for helical gears such as the one disclosed in the above-mentioned US patent is currently available, the technology for industrially mass-producing helical gears has not been established, and it has not yet been established that helical gears can be used in transmissions for automobiles and motorcycles. Despite being a major part for transmitting rotation in many machines, helical gears are currently formed by cutting using hobbing machines.

[Purpose of the invention]

The present invention was made to solve the above-mentioned problems, and eliminates the occurrence of lead gaps and the resulting seizure and galling between the mold and the material, and enables industrial mass production of helical gears. The purpose of the present invention is to provide a helical gear plastic processing device.

[Means for solving problems]

The helical gear plastic processing device according to the present invention 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 able to rotate relative to each other in the circumferential direction, and a die arranged on the central axis line between the container and the die. A mandrel and a punch for sequentially pushing the metal material into the gap between the mandrel, the container, and the die are provided, and the inner wall of the die has a helical gear tooth profile that changes from the inner surface of the upper end toward the material extrusion direction. An approach part and a product shape part of a helical gear tooth profile connected thereto are formed, and on the container side of the mandrel, an enlarged diameter part is formed by expanding the diameter of the metal material to set the cross-sectional area necessary for forming the helical gear. At the same time, the horizontal cross-sectional area of the material is kept constant even if there is a substantial reduction in the outer diameter during the process in which the outer circumference of the material is gradually flow-deformed into a helical gear tooth shape by the approach portion of the die, facing the approach portion of the die. An inner diameter portion is formed to reduce and deform the inner diameter of the material, and a cylindrical portion is further formed opposite to the product shape portion of the die to set the inner diameter of the molded product to a regular dimension.

[Action of the invention]

In the present invention, when the metal material that is sequentially pushed into the gap between the container and the mandrel by a punch passes through the expanded diameter part of the mandrel, the diameter is expanded to the cross-sectional area necessary for forming the helical gear, and the metal material is expanded in diameter to the cross-sectional area necessary for forming the helical gear. When passing between the opposing inner diameter forming parts, the outer peripheral part of the material is fluidly deformed from an incomplete tooth profile to a complete tooth profile depending on the shape of the approach part, and at the same time, the material is substantially The flowing material that accompanies the reduction in the outer diameter is absorbed by the inner diameter forming part, which has a reduced diameter shape in the opposite direction to the enlarged shape of the approach part, thereby causing the metal material to flow and expand in the axial direction. In addition to preventing lead gaps from occurring, the container and die can rotate relative to each other in the circumferential direction, which prevents seizure, galling, and tooth damage between the material and the die. Prevent occurrence.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. FIG.

Fig. 1 is a sectional view showing the overall configuration of a helical gear extrusion plastic processing device according to the present invention, Fig. 2 is an enlarged sectional view of the main parts, and Fig. 3 is a helical gear formed by pushing a metal material into a molding die. FIG.

In FIGS. 1 to 3, a helical gear molding die designated by the general reference numeral 1 includes a container 2, a die 3,
and a mandrel 4. An insertion hole 2a for restricting the external shape of the metal material 5 is formed in the center of the container 2, passing through in the vertical direction, and this hole 2a restricts the external shape of the metal material 5.

The die 3 is used to form twisted teeth on the outer periphery of the material by pushing the metal material 5 into it, and is supported so as to be movable up and down on a plurality of guide rods 8 vertically attached to a fixed part 7 such as a bolster. The container 2 is rotatably fitted into the mounting hole 9a of the support plate 9, and the containers 2 are superimposed on the upper surface of the die 3 with their axes aligned.
and the die 3 have a flange 2 formed on the outer periphery of each
b and the flange 3a are held by a ring-shaped holder 11 fixed to the support plate 9 with bolts 10 so as to be rotatable relative to the support plate 9 in the circumferential direction. Further, the support plate 9 is always urged upward by a compression spring 12 disposed coaxially with the guide rod 8 between the support plate 9 and the fixed portion 7.

Furthermore, the die 3 has a cylindrical hole 31 with a slightly larger diameter than the material insertion hole 2a of the container 2, and the inner wall of this cylindrical hole 31 has a tooth portion 32 for forming a helical gear torsion tooth to create a desired twist. formed of corners. As shown in FIG. 2, the tooth portion 32 has an approach portion (an approach portion) that expands linearly from the inner surface of the cylindrical hole 31 toward the center as it goes in the direction of extrusion of the metal material 5 (direction of arrow X in FIG. 2). tooth deformation process)
32a, and a product-shaped portion 32b that is connected to the lower end of the approach portion 32a and forms a complete helical gear tooth profile, and the cross-sectional shape of the area of the approach portion 32a is as follows:
As shown in FIG. 4, the tooth groove width d decreases from the inner surface of the cylindrical hole 31 toward the center in accordance with the involute curve of the molded tooth. This increases the bending rigidity of the starting end portion (corresponding to the approach portion 32a) of the approach portion 32a when the material 5 begins to be fluidly deformed along the approach portion 32a, and the fluid deformation of the material 5 to the helical gear teeth smoothly transitions. It is becoming possible to do so.

A mandrel 4 arranged on the central axis of the material insertion hole 2a of the container 2 and the cylindrical hole 31 of the die 3 is a guide that is located in the material insertion hole 2a of the container 2 and into which the center hole 5a of the metal material 5 fits. a cylindrical part 41, and an enlarged diameter which is connected to the lower end of this cylindrical part 41 via a taper part 42, is located inside the cylindrical hole 31 of the die 3, and sets the metal material 5 to the cross-sectional area necessary for helical gear forming. portion 43, and the outer periphery of the metal material 5 is connected to the lower end of this enlarged diameter portion 43 facing the tooth approach portion 32a of the die 3.
A material inner diameter forming part 44 that restrains and supports the inner diameter of the material in the reduction direction as the substantial outer diameter of the metal material 5 is reduced in the process of being sequentially flow-deformed from a circle to a helical gear, and a lower end of the material inner diameter forming part 44. ni die 3
A cylindrical part 45 is provided in series to face the tooth product shaped part 32b, and sets the normal inner diameter dimension of the helical gear to be molded.

1 and 3, 13 is the slider 1
This punch 13 is a cylindrical punch supported by a holder 15 on the lower surface of the container 2 and the die 3.
This is for pushing the metal material 5 into the gap between them, and has a support structure that can rotate in the circumferential direction with respect to the slider 14.

Next, a case will be described in which a helical gear is extruded using the mold 1 configured as described above.

First, as shown in FIG. In the fitted state, the slider 14 is moved downward in the direction of arrow A. As a result, when the punch 13 engages with the upper end of the metal material 5 and is further lowered, the entire support plate 9 including the container 2, die 3 and mandrel 4 is lowered against the compression spring 12, and the die 3 When the lower end surface of the mandrel 4 comes into contact with the upper surface of the pedestal 16 installed on the fixed part 7, the container 2, the die 3, and the mandrel 4 stop descending.

In this state, when the punch 13 is lowered to its full stroke by advancing the slider 14 in the direction of the arrow A, the metal material is pushed into the gap between the container 2 and the mandrel 4 in the extrusion direction shown by the arrow X.
Container 2 and die 3 as shown by reference numeral 5' in FIG.
It is pushed into the position where it straddles between the two.

When the metal material is pushed into the die 3 from the container 2 by the punch 13, the diameter of the metal material 5' is expanded by the enlarged diameter portion 43 in the mandrel 4, and the cross-sectional area is set to be necessary for forming a helical gear. Ru. The lower end side outer periphery is the twisted tooth forming tooth part 3 of the die 3.
2, and begins to form the twisted teeth on the metal material 5'. At this time, the material deformation state of the outer peripheral portion of the metal material 5' corresponds to the cross-sectional shape of the approach portion 32a shown in FIG.

When the punch 13 has completed the full stroke of the first metal material 5', the punch 13
is raised, the next metal material 5 is inserted into the container 2 as shown in FIG. 1, and the punch 13 is lowered again to push the metal material 5 into the container 2. In the same manner, punch 1 the metal material 5 into the container 2.
3, the metal material 5 moves sequentially in the direction of the arrow X within the gap between the die 3 and the mandrel 4, and while passing through the gap between the die 3 and the mandrel 4, the metal material 5 moves around the outer periphery. This will be plastically worked into a helical gear with twisted teeth.

That is, the metal material 5 is in the approach portion 32 of the die 3.
When passing through a, the outer periphery of the metal material 5 is gradually changed from a circle to a perfect helical tooth shape, and the product shape part 32b and the mandrel 4 opposite thereto are formed.
When the material passes between the inner diameter forming portions 44, the outer circumference of the material has completely twisted teeth 17 as shown in FIG.
a is formed, and the helical gear 17 whose inner diameter 17b is formed to a predetermined diameter by the inner diameter forming portion 44 is formed. This helical gear 17 falls into the pedestal 16.

Here, when the metal material 5 sequentially pushed in from above by the punch 13 passes between the approach portion 32a of the tooth portion 32 of the die 3 and the material inner diameter forming portion 44 of the mandrel 4 opposing this, the outer circumference of the metal material 5 is fluidly deformed from an incomplete tooth profile to a complete tooth profile as it goes from the upper end to the lower end of the approach portion 32a, and at the same time, the fluid material accompanying the substantial outer diameter reduction of the material 5 in this tooth deformation process It is absorbed by the material inner diameter forming portion 44 which has a diameter reduction slope opposite to the expansion slope of the portion 32a, and prevents the metal material 5 from flowing and expanding in the axial direction of the mandrel 4.

That is, the inner diameter forming portion 44 of the mandrel 4 that restrains the inner diameter side of the metal material 5 prevents the decrease in the cross-sectional area of the metal material 5 in the horizontal plane due to the flow deformation of the outer peripheral portion of the metal material 5 from a circle to a twisted tooth. The diameter is absorbed by reducing the diameter according to the change in the cross-sectional shape of the inclined approach portion 32a, and the cross-sectional area of the material 5 on the horizontal plane is kept constant throughout the material flow deformation region within the mold.

FIG. 6 is an explanatory diagram showing that the cross-sectional area of each part in the horizontal plane during the helical gear forming process in the mold is constant.

6A shows a cross section of the metal material 5 along line A-A in FIG. 3, and FIG. 6B shows a cross section of the material in the middle of deformation along line B-B in FIG. 6C shows a cross-sectional view of the completed product taken along the line C--C in FIG. 3.

As is clear from these figures, the cross-sectional area S _A of the material 5 whose diameter has been expanded by the expanded diameter part 43 of the mandrel 4, the cross-sectional area S _B of the material in the middle of deformation, and the cross-sectional area S of the completed gear are S _A = S _B =S. However, the relationship between the inner diameters φ _dA , φ _dB , and φ _dC is φ _dA > φ _dB > φ _dC .

Therefore, material expansion in the axial direction of the material 5 is prevented, and even on the way from the approach portion 32a of the die 3 to the product shape portion 32b where a perfect tooth shape is formed, the lead of the incomplete tooth shape formed on the outer periphery of the material is prevented. A gap does not occur between the leads of the die tooth profile that are in contact with this. Furthermore, there is no lead error between the advancing direction of the tooth profile formed on the outer periphery of the material and the corresponding tooth portion of the die 3, and perfect twisted teeth are formed on the outer periphery of the material.

Further, when the metal material 5 pushed in by the punch 13 passes through the tooth portion 32 of the die 3 while being fluidly deformed, a relative rotational force is generated between the metal material 5 and the die 3 due to the helix angle of the tooth portion 32. That is, assuming that the die 3 is in a fixed state, if one metal material 5 approaches the teeth 32 of the die 3 by pushing, the entire material will not be rotated by the twisted leads of the teeth 32. I don't get it. In this state, most of the material is in the container 2, so if the die 3 and the container 2 are integrated or the rotational movement between the die 3 and the container 2 is restricted, the friction between the container 2 and the material The material must overcome resistance and rotate. At this time, since a part of the material 5 is only about to reach the approach portion 32a of the die 3, the rotation of the material 5 generates extreme stress in the approach portion 32a, causing unnecessary deformation of the material 5. Otherwise, the teeth 32 of the die 3 may be damaged.

However, in this embodiment, container 2,
Since the die 3, mandrel 4, and punch 13 are rotatably supported relative to each other, the above-mentioned problems do not occur at all, and it is possible to plastically process a helical gear with high precision.

Furthermore, by forming the approach portion 32a of the tooth portion 32 for forming twisted teeth of the die 3 into a cross-sectional shape that slopes upward in the extrusion direction of the material as shown in ~ in Fig. 4, it is possible to form twisted teeth on the material. This can be done easily and with high precision, and mold machining can be simplified, the rigidity of the teeth 32 can be increased, and the life of the mold can also be improved.

〔Effect of the invention〕

As described above, according to the present invention, the outer shape restraining container into which a metal material having a center hole is inserted and the die connected below the container are arranged so as to be relatively rotatable in the circumferential direction, and the central axis between the container and the die is A mold for forming a helical gear by arranging a mandrel on a line and sequentially pushing the metal material into the gap between the mandrel, the container, and the die using a punch. Accordingly, an approach part that changes to a helical gear tooth profile and a product shape part of a complete helical gear tooth profile are formed connected to this, and the diameter of the metal material is expanded on the mandrel to set the cross-sectional area necessary for forming the helical gear. In addition to forming the enlarged diameter part on the container side, there is a substantial reduction in the outer diameter in the process where the outer peripheral part of the material is gradually flow-deformed into a helical gear tooth profile by the approach part, facing the approach part of the die. Also, 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 is constant, and a cylindrical part is formed opposite to the product shape part of the die to set the inner diameter of the molded product to a regular dimension. Therefore, it is possible to prevent the occurrence of lead gaps and the occurrence of seizure and galling between the die teeth and the material due to this, and it is also effective in facilitating the industrial mass production of helical gears.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of a helical gear plastic processing device according to the present invention, Fig. 2 is an enlarged sectional view of the main parts thereof, and Fig. 3 is an extrusion process of a helical gear by pushing a metal material into a mold. A sectional view showing a state in which
Fig. 4 is an explanatory diagram showing the changing state of the approach portion of the die tooth portion, Fig. 5 is a partially cutaway side view of the molded helical gear, and Figs. 6 A to C are flow diagrams of the material in the embodiment of the present invention. FIG. 3 is an explanatory diagram showing the horizontal cross-sectional area state during the deformation process. 1... Mold, 2... Container, 2a... Insertion hole for material restraint, 3... Die, 31... Cylindrical hole, 3
2...Tooth portion for helical gear tooth formation, 32a...
...Approach section, 32b...Product shape section, 4...
Mandrel, 43... Expanded diameter part, 44... Material inner diameter forming part, 45... Cylindrical part.

Claims (1)

[Claims] 1. A container for external restraint into which a metal material having a center hole is inserted, a die located below this container and arranged so as to be relatively rotatable in the circumferential direction, and arranged on the center axis of the container and the die. A punch is provided for sequentially pushing the metal material into the gap between the mandrel, the container, and the die. An approach part to be formed and a product shape part of a helical gear tooth profile connected thereto are formed, and an enlarged diameter part is formed on the container side of the mandrel to enlarge the diameter of the metal material and set the cross-sectional area necessary for forming the helical gear. At the same time, the horizontal cross-sectional area of the material remains constant even if there is a substantial reduction in the outer diameter during the process in which the outer periphery of the material faces the approach portion of the die and is gradually transformed into a helical gear tooth shape by the approach portion. The plasticity of the helical gear is characterized in that an inner diameter part is formed to reduce and deform the inner diameter of the material, and a cylindrical part is formed opposite to the product shape part of the die to set the inner diameter of the molded product to a regular dimension. Processing equipment.