JP2000117389A - Gear forging method by vertical type press machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to produce a rough forged part of a gear not having an underfill part to an corner part, etc., of a gear tip without increasing the number of processes. SOLUTION: In the process to produce a rough forged part of a gear by blanking a shaft hole to hot finished forged parts 21, 22 in a gear forging method by a vertical type press machine, by a work holding member 15 used for holding the hot finished forged parts 21, 22 in the process before blanking the shaft hole, stress is applied to the hot finished forged parts 21, 22 so as to reshape the underfill part of an corner part of a tooth tip.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for hot forging gears with a vertical press.

[0002]

2. Description of the Related Art Conventionally, forging gears are manufactured by heating a columnar material 5 as shown in FIG. 1A in a heating furnace by using a vertical press machine, and then as shown in FIG. The crush 4 is obtained by forcibly applying pressure in the vertical direction, and the die is forged to form a wasteland 3 as shown in FIG. Put this wasteland 3 in the lower mold 20 ₁ having a toothed Gyabite (Figure 2), the outer shape is strongly pressed using toothed upper die 13 ₁ (FIG. 2), the teeth 6 (FIG. 3) as extruded and hot finish forged product 2 ₁ gear as shown in (d), the end of the gear by punching a lighter hole 10 provided in accordance with the axial hole 9 and must, as shown in (e) Roughly forged product 1.

[0003] step of punching the weight reduction holes 10 provided in accordance with the axial hole 9 and necessary, lower mold 20 ₂ 9
Extent to place the hot finish forgings 2 ₁ gear, not deform the forging 2 ₁ tip 16 ₁ of tooth cylindrical workpiece having substantially the same diameter as the wheel of the dedendum 12 pressing member 15 ₁ is finishing on the _First , the upper die support and die block 17 are lowered and held along the upper die guide 14 on the hot finished forged product 21, and the shaft hole 9 and the lightening hole 10 provided as necessary are punched out. The punch 18 and the punch 19 for weight reduction were pressed to make a hole to produce a gear of the rough forged product 1 as shown in FIG. 1 (e) and FIG.

[0004] However, the rough forging of the gear 1 by the forging method described above.
When producing, in the step of producing a hot finish forged product 2 _1, addendum of the gear-shaped Gyabite, especially for filling of material into the tooth tip 24 of the lower die 20 ₂ (FIG. 2) is insufficient , Figure
As shown in FIG. 10, the underfill 26 was formed particularly at the tip of the lower tooth, and the undercut was removed by machining in a subsequent process so as to eliminate the underfill. Therefore, there is a disadvantage that the amount of machining is increased and a large amount of material is wasted.

Therefore, in order to eliminate the underfill 26 at the tip of the tooth,
The large diameter and width of the teeth of this rough forged product are slightly larger than the final dimensions, and the teeth are sized by cold forging to reduce the large diameter and width of the teeth and the material is transferred to the tooth tip surface. In the final stage of this sizing, coining is performed to strongly press the end face of the tooth, feed the material to the corner where the end face and the tooth tip intersect, fill in the underfill in the corner, Japanese Patent Application Laid-Open No. 8-108771 discloses a method of integrally manufacturing a counter driven gear with a parking lock gear having no underfill. However, in this method, since the rough forging is further cold forged in order to eliminate the underfill of the tooth tip, the number of processes is increased by one, and a die and a press for that are required. There is.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a rough forged product of a gear having no underfill at a corner portion of a tooth tip without increasing the number of steps.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have investigated and researched a hot forging method for gears, and have punched out a shaft hole and a hole for reducing the weight as necessary. in step, place the hot finish forged product 2 ₁ gear on the lower mold, the lower the workpiece holding member 15 ₁ of the upper mold 13 ₂ in order to suppress the heat-finished forged product 2 _1, the Since the hot-finished forged product 2 ₁ had been processed and became thinner, the processed product holding member 15 ₁ was replaced with the hot-finished forged product 2 ₁
Not only lower in order to suppress, in which no knowledge present invention to obtain the can shaping process be added stress to the hot finish forged product 2 ₁ by the workpiece holding member 15 _1.

That is, in the gear forging method using the vertical press machine according to the present invention, the gear hole is punched out by punching the shaft hole and, if necessary, the lightening hole provided in the hot finish forged product in the gear forging method using the vertical press machine. In the process of forming a rough forged product, before punching out the shaft hole and the hole for reducing the weight to be provided as necessary, the workpiece holding member used in this process applies the upper die support and the die block to the hot finished forged product. A high stress is applied by using a spring having a high spring constant as a spring used therein, and shaping is performed so as to compensate particularly for a missing portion such as a corner portion of a tooth tip.

Further, in the gear forging method using a vertical press according to the present invention, the tip or the entire outer shape of the work holding member is formed in a columnar shape having substantially the same diameter as the addendum circle of the gear of the hot finished forged product. Or a gear shape substantially the same as the outer shape of the gear. Further, in the gear forging method by the vertical press machine of the present invention, at least the lower side, that is, the lower side or the lower side and the upper side, so that the teeth of the gear of the hot finished forged product become thicker toward the tip. Is provided with a taper.

[0010]

According to the present invention, in the step of forming a shaft hole and a lightening hole provided as required into a rough forged product of a punched gear, the work piece holding member used in this step is simply pressed before punching the shaft hole or the like. Only apply greater stress,
By applying a force to the hot finished forged product, it can be shaped so that there is no underfill such as a corner at the tip of the tooth.

Further, at this time, the shape of the tip end of the workpiece holding member is formed in a columnar shape having substantially the same diameter as the addendum circle of the gear of the hot-finished forged product, or in the same gear shape as the outer shape of the gear. Since the stress can be directly applied to the gear teeth of the hot-finished forged product, the underfill can be more reliably shaped. In addition, since the gear teeth of the hot-finished forged product are made thicker toward the tip, the underfill can be compensated for from the place close to the underfill, so the underfill can be shaped more reliably. Can be done.

[0012]

Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a process diagram for explaining the entirety of the present invention and a conventional gear forging method using a vertical press machine, and FIG. 2 is a mold for forging the present invention and a conventional rough terrain into a hot finished forged product. FIG. 3 is a perspective view of an example of a gear manufactured by the gear forging method using the vertical press according to the present invention, and FIG. 4 is a diagram illustrating a hot finished forged product of the present invention forged into a rough forged product. FIG. 5 is a cross-sectional view for explaining another embodiment of the process shown in FIG. 4, and FIG. 6 is a cross-sectional view for explaining another embodiment of the present invention. FIG. 7 is a partially enlarged perspective view of the gear of FIG. 6, and FIG. 8 is a sectional view of a mold and rough ground used for manufacturing the gear of FIG.

A vertical press (not entirely shown) used in the gear forging method using the vertical press of the present invention has a known structure, and includes a step of crushing (b), a step of die forging. A vertical press machine that performs each of the steps of making a rough land (c), a step of making a hot finished forged product (d), and a step of making a rough forged product (e) can simultaneously perform two or more of these steps. Although a die press or a vertical press capable of simultaneously performing these four steps may be used, a vertical press capable of simultaneously performing these four steps is more preferable because the moving distance of the forged product can be reduced.

[0014] hot finish forged product 2 ₁ in the gear forging method according to a vertical press machine of the present _invention, 2 _2, rough forging gears by punching a lighter hole 10 provided in accordance with the axial hole 9 and optionally after As shown in FIG. 1 (d), an outer peripheral portion provided with teeth 6 around the periphery is fixed to a central boss 7 via a rib 8, and this boss 7 has one axial hole. Part is provided. Method for producing the hot finish forged product 2 _1, 2 _2, after heated by the heating apparatus similar to the conventional manner, i.e. a short cylindrical elements 5 as shown in FIGS. 1 and 2, in the vertical direction It is crushed to form a crush 4 and further forged into a wasteland 3. Put this wasteland 3 in the lower mold 20 ₁ having a toothed Gyabite, the main punch upper die 13 _first outer shape of the gear-shaped
The method may be the same as the method in which the tooth 6 is extruded by strongly pressing the punch 21 for the shaft hole and the shaft hole 22, or may be another known manufacturing method. Reference numeral 23 in FIG. 2 and the like denotes a knockout pin.

[0015] The above hot finish forging teeth 6 of the gear of the present invention, widths h ₁ and addendum of the tooth root, as shown in FIG. 1 (d)
h ₂ may be the same, but to compensate for the underfill from near the underfill portions of thicker tooth tip than the width h ₃ width h ₄ of sea urchin tooth is dedendum of 6 and 7 It is preferable because it is possible. The tooth tip width h ₄ thick gears 2 ₂ hot finish forging than the width h ₃ of the dedendum is lower die used in the manufacturing process of the hot finish forgings gear 8 20 It can be manufactured by using the cavities of No. ₂ formed so that the tip 24 is deeper than the root 25.

Gear forging method using the vertical press of the present invention
Hot forgings in Japan 2₁, 2_TwoTo make a rough forged product
Punches the shaft hole 9 and the hole 10 for weight reduction provided as necessary.
Before removing, remove the workpiece holding member 15 used in this process.₁,
Fifteen_TwoHot finished forgings by 2₁, 2_TwoTo stress
Finished forgings are shaped and used for this shaping.
Workpiece holding member 15₁, 15_TwoHas the same tip as before
In the same way, it is almost the same as the root circle 12 (Fig. 3) of the hot finish forging.
Cylindrical with a diameter of 16₁(FIG. 9), but as shown in FIG.
Cylindrical shape with approximately the same diameter as tip circle 12_TwoOr
As shown in Fig. 5, the outer shape of the tip is the tooth of the hot finished forged product.
Gears that are almost the same as the shape of the car 16 _ThreeIs better for your teeth
It is preferable because a direct stress is applied.

A method and an apparatus for applying stress to the hot finish forged products 2 ₁ , 2 ₂ by the work product holding members 15 ₁ , 15 ₂ are as follows.
In the case of using the conventional apparatus as shown in FIG. 4, the spring (used to absorb the backlash of various equipment such as a work holding member) used in the upper die support and die block 17 and the shaft hole punching punch 18 are used. and it serves to release not to tell bite the tip portion 16 ₂ of the workpiece holding member after drilling a shaft hole or lighter hole 10 in lighter hole unannounced punch 19.) using a high spring constant spring as And workpiece holding member 15
_1, 15 ₂ makes it possible to so as apply a high stress in the hot finish forged product 2 _1, 2 _2. Also, if you move up and down the workpiece holding member 15 ₂ by other methods, the hot finish forgings 2 ₁ a force that moves up and down strongly to the workpiece holding member 15 _1, 15 _2, 2 ₂ Can be stressed.

The present invention, processed products pressing member 15 _1, 15 hot finish forged product 2 ₁ by _2, 2 ₂ stress to be able to add to, the workpiece holding member 15 ₂ If necessary, 15 ₃
The shape of the tip of the gear should be cylindrical with a diameter approximately the same as the tip circle of the gear of the hot-finished forged product, or approximately the same as the external shape of the gear of the hot-finished forged product. finish forging 2 _1, 2 ₂ of the Kyabite the lower die 20 ₂ so that the thick accordance teeth 6 of the gear toward the tip addendum 24, as shown in FIG. 8 is deeper than the tooth root 25 as By using the molded product, it is possible to manufacture a rough forged product of a gear having no underfill at a corner of a tooth tip or the like.

[0019]

The gear forging method using the vertical press according to the present invention has the above-mentioned structure, so that the number of steps is not increased, and a gear having no underfill is produced by the same manufacturing process and method as before. It has an excellent effect that a rough forged product can be manufactured.

[Brief description of the drawings]

FIG. 1 is a process diagram for explaining the entirety of a gear forging method according to the present invention and a conventional vertical press.

FIG. 2 is a cross-sectional view of a die and a wasteland for forging a wasteland according to the present invention and a conventional wasteland into a hot finish forged product.

FIG. 3 is a perspective view of one embodiment of a gear manufactured by a gear forging method using a vertical press according to the present invention.

FIG. 4 is a cross-sectional view for explaining one embodiment of a step of forging a hot finished forged product into a rough forged product of the present invention.

FIG. 5 is a sectional view for explaining another embodiment shown in FIG. 4;

FIG. 6 is a sectional view of a gear of a hot finish forged product used in the gear forging method according to one embodiment of the present invention.

FIG. 7 is a partially enlarged perspective view of FIG.

FIG. 8 is a cross-sectional view of a mold and a wasteland used for manufacturing the one shown in FIG.

FIG. 9 is a cross-sectional view for explaining a step of forging a conventional hot finish forging into a rough forging.

FIG. 10 is a partially enlarged perspective view for explaining a missing portion of a gear in a hot finish forged product of a gear manufactured by a conventional gear forging method.

[Brief description of reference numerals]

1 ₁ , 1 ₂ Rough forged product 2 ₁ , 2 ₂ Hot finished forged product 3 Wasteland 4 Crush 5 Material 6 Teeth 7 Boss 8 Rib 9 Shaft hole 10 Lightening hole 11 Tooth circle 12 Tooth circle 13 ₁ , 13 ₂ Upper die 14 Upper die guide 15 ₁ , 15 ₂ Workpiece holding member 16 ₁ , 16 ₂ Tip part of workholding member 17 Upper mold support and die block 18 Shaft hole punching punch 19 Hole punching for weight reduction Punch 20 ₁ , 20 ₂ Lower die 21 Main punch 22 Punch for shaft hole 23 Knockout pin 24 Tooth tip 25 Root 26 Notch

Claims (3)

[Claims] 1. A hot finish forging in the gear forging method according to a vertical press machine (2 _1, 2 ₂₎ to a step of the shaft hole (9) punched on the gear rough forging (1), shaft hole before stamping (9) vertical, characterized in that shaping processability by adding stress to the workpiece holding member to be used in this step (15 _1, 15 ₂₎ by hot finish forgings (2 _1, 2 ₂₎ Gear forging method using a die press. 2. The workpiece holding member (15 ₂ ) has at least the outer shape of the tip portion having a diameter substantially equal to the tooth tip circle (11) of the gear of the hot finish forged product (2 _1, 2 ₂ ). The gear forging method using a vertical press according to claim 1, characterized in that the gear forging is a pillar-shaped one (16 ₂ ) or a gear-shaped one (16 ₃ ) having substantially the same outer shape as the gear. 3. The gear of the hot-finished forged product (2 ₂ ), wherein the gears are formed such that their teeth become thicker as they go toward the tip. Gear forging method using a vertical press machine.