JPH11129051A - Hot forging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the forging device which enables a punch processing to a shaft part protruding from a plate part of a front hub, without having a work deformed, utilizing an existing press unit. SOLUTION: The device comprises; a bed 10 having a cushion mechanism 12, a press unit 2d having a ram 11, into which a pair of ring shape upper/ bottom dies 14, 20 presses the hub plate part 3 nipping down, covering a peripheral face of the front hub shaft part 4, by an approaching operation of the ram 11, and a counter punch 26, an upper punch 27 to shear and make a hole on the shaft center via a hollow part of the upper/bottom dies 14, 20, making use of a sinking movement of the cushion function while the front hub being nipped by the upper/bottom dies 14, 20. The hole punching of the front hub shaft is thus made possible, utilizing the existing press unit 2d and making use of an easy deformability by heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot forging apparatus for forming a hole in a column of a work in which a plate and a column are formed.

[0002]

2. Description of the Related Art A front hub for supporting a front wheel of an automobile is:
Generally, after being formed by a hot forging device, a through hole is machined at the center of the shaft to produce a product. Specifically, the hub material is heated to a predetermined temperature, for example, 1100 ° C to 125 ° C.
It is heated to 0 ° C and sent to a hot forging device in which a plurality of press sections are arranged in order. From the first press section to the middle press section, a thin circular plate section and the center of the plate section are used. The hub material (work) having a columnar shaft (column) protruding from the center (center) is forged, and the subsequent press section removes the burrs protruding from the outer peripheral end of the hub material to remove the front hub. The outer shape is molded. After that, the outer part of the front hub, which is free of outer peripheral burrs, is formed by hot forging using a mold (sealed mold) that covers the periphery of the hub material by drilling holes in the shaft part and performing a similar progressive pressing process. Then, the front hub is commercialized by drilling holes in the shaft.

By the way, hot forging (including closed forging) is
Heat the material to a temperature suitable for processing (for example,
(1250 ° C.), and the shape of the material (forged product) can be easily formed because the material is easily deformed, but it protrudes from the center of the thin plate portion such as the front hub. It is difficult to form a small-diameter through-hole in the shaft portion because the material tends to be deformed by the pressure applied to the material, especially the thin plate portion.

Therefore, conventionally, when the outer shape of the hub part is finished without using a hot forging apparatus, a hole is formed in a shaft portion by machining, specifically, using a drill, and thereafter, Finishing processing was performed on the drilling surface by cutting to drill holes.

[0005]

It is required to reduce the processing cost of parts such as the front hub as much as possible. However, on the shaft of the hot forged material,
Machining (roughing by drilling, finishing by cutting)
In this case, making a hole requires a lot of time and effort, and considerably increases the processing cost.

[0006] On the other hand, the molding of parts by closed forging suppresses the loss of material, and eliminates the need for a step of treating the outer peripheral burrs by a deburring press having a cushion mechanism previously incorporated in a mold. In recent years, the tendency to use closed forging has been increasing.

For this reason, there is a demand for a technique capable of utilizing the press section of the hot forging apparatus to make a hole in the shaft section while reducing the labor and processing cost involved in processing the shaft section. The present invention has been made in view of the above circumstances, and the purpose thereof is to make use of an existing press part and to perform a hole punching process on a pillar part erected from a plate part without deforming a work. It is to provide a hot forging device that can be applied.

[0008]

According to a first aspect of the present invention, there is provided a hot forging apparatus, comprising: a bed having a cushion mechanism; a press section having a ram; A pair of ring-shaped holding dies that sandwiches and pushes down the plate while covering the outer peripheral surface of the plate, and an inner punch that punches the center of the column by shearing using the movement of the holding mechanism to sink the cushion mechanism while holding the work in between Combining the outer punch with the knock pin that pulls out the chip from the outer punch, the existing press section is used to prevent deformation of the work, and to easily deform the work by heating, and Holes can be punched.

According to this hot forging apparatus, a work heated to a predetermined temperature and molded is set in a predetermined direction between the bed and the ram, and the ram is moved toward the bed to approach. Then, the outer peripheral surface of the column part is covered while the plate part is sandwiched between the one holding type supported by the cushion mechanism and the other holding type supported by the ram.

As a result, the outer surfaces of the work (the column and the plate) which are easily deformed are restrained from being unnecessarily deformed. By the approaching movement of the ram that follows, the holding mold sinks while sandwiching the work.

Then, the inner punch is inserted from the hollow portion of the holding die toward the center of one shaft end of the pillar portion. Here, since the outer punch restrains the outer peripheral portion of the shaft end on the opposite side of the pillar, only the solid portion of the pillar is pushed out into the outer punch while shearing as the inner punch advances.

When the inner punch advances until it penetrates the pillar portion, the entire pillar portion is punched without deforming the work. After punching, push out the chip in the outer punch with a knock pin to prepare for the next punching process.

[0013] By such a punching process, a work in which a pillar portion is erected on a thin plate portion can be punched without giving unnecessary deformation to the work by using a hot forging press portion. Can be done.

As a result, subsequent to the step of forming the outer shape by hot forging, hole punching of the pillar portion is realized, which reduces labor and processing cost, thereby improving production efficiency. In addition, by simply combining the press part of the existing hot forging device with the pressing die, the punch part, and the knock pin, the hole of the pillar part can be easily removed.

According to a second aspect of the present invention, in addition to the above object, in order to surely suppress deformation of the work, the hot forging apparatus has a surface for sandwiching the holding die plate portion according to the first aspect. It is formed on a mold surface that follows the shape.

In the hot forging device according to the third aspect of the present invention, the rough positioning of the outer punch further causes the tip of the outer punch to come into close contact with the shaft end of the pillar portion, and the workpiece is sandwiched by the holding die and sunk. The outer punch according to claim 1 or 2 is supported on a ram via a punch cushion mechanism.

According to a fourth aspect of the present invention, the hot forging apparatus further protects the inner punch, which receives heat when shearing the workpiece, from heat damage. Around the inner punch is provided with a spray nozzle for spraying the coolant toward the inner punch.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on one embodiment shown in FIGS. FIG. 1 (a)
For example, a hot forging apparatus 1 for manufacturing a front hub Z (a product outer shape is shown in FIG. 6B) for supporting a front wheel of a vehicle from a cylindrical hub material X1 by hot forging is shown.

The hot forging apparatus 1 has a plurality of, for example, four press sections 2a to 2d arranged in a line on a straight line, and a feed section (not shown) for feeding the press sections 2a to 2d in order. A bed and a ram with a cushion mechanism, which constitute the press sections 2a to 2c, are equipped with a mold for sealing forging (neither is shown). No. 1 from the press section 2a. In the section up to the press section 2c, for example, a hub material X1 of a predetermined shape heated to, for example, 1100 ° C. to 1250 ° C. is sequentially sealed and forged (using a mold that covers the periphery of the hub material X1 so as to prevent generation of outer peripheral burrs. Forging) to form the entire outer shape of the front hub Z. Specifically, NO. When the step of the pressing section 2c of FIG. 3 is completed, a thin circular plate section 3 as shown in FIG.
An intermediate hub material that has just finished forming the outer shape of the cylindrical shaft portion 4 (solid column portion) protruding by a predetermined length from the center (center) of the hub, that is, a hub material X2 having no outer peripheral burrs.
(Corresponding to the work of the present application).

The depressed press portion 2d is a portion which is not usually used when forming a product by closed forging (since no outer peripheral burrs occur in closed forging). Therefore, in the present embodiment, in order to utilize the existing press portion 2d, it is possible to perform the forging of the shaft portion 4 of the hub material X2, which is difficult, by the hot forging in the press portion 2d.

That is, the depressed press portion 2d has:
As shown in FIG. 1 (b), various devices for punching the shaft portion 4 of the hub material X2 are attached in place of the blanking die, and a dedicated punching portion 5 ( Hot forging).

Thus, the NO. Hole processing is performed on the hub blank X2 after the process of the press section 2c of No. 3 is completed. Specifically, the hole punching section 5 has a structure as shown in detail in FIG.

The hole punching section 5 will be described.
In the drawing, reference numeral 10 denotes a bed with a lower cushion mechanism constituting the existing press section 2d, and reference numeral 11 denotes a ram arranged above the bed 10. The ram 11 is connected to, for example, a crank type ram elevating device (not shown), and is configured to lower from top dead center to bottom dead center or return to top dead center while applying a predetermined force. That is, the ram 11 moves in the direction of coming into contact with and separating from the bed 10.

From the upper surface of the bed 10, an operating rod (not shown) of the floating air cylinder 12 constituting a cushion mechanism is provided so as to surround a central portion of the bed 10.
The tip ends of a plurality of die cushion pins 13 connected to the projection slidably project at predetermined intervals.

The die cushion pin 13 and the ram 11 have a pair of ring-shaped upper dies 14 and lower dies 20 serving as a pair of holding dies that sandwich the hub material X2 from above and below, instead of the existing demolding dies. Is assembled.

More specifically, the upper die 14 has, for example, a disk shape having a size corresponding to the outer diameter of the hub material X2, and a support ring 15 having an inverted L-shaped cross section is attached to the upper end. .

The support ring 15 is slidably fitted to, for example, a clip ring 16 having a substantially inverted T-shaped cross section assembled to the lower surface of the ram 11, and the upper die 14 is attached to the lower surface of the ram 11 in an upward direction. Hanging movably. Note that 16
a indicates a mounting seat for fixing the clip ring 16 to the lower surface of the ram 11.

In the center of the upper die 14, a through hole 17 corresponding to the shaft diameter of the shaft 4 of the hub material X2 is vertically penetrated. On the lower surface of the upper die 14 (corresponding to a surface sandwiching the plate portion), a die surface 18 having a shape similar to each upper surface portion of the plate portion 3 of the hub material X2 is formed.
7, the outer peripheral surface of the shaft portion 4 is covered, and the upper surface of the plate portion 3 is pressed down by the wall surface 18 while maintaining the same shape.

The lower mold 20 has a disk shape having a size corresponding to the outer diameter of the plate portion 3. In the center of the lower die 20, a through hole 22 having substantially the same diameter as the through hole 4a formed in the shaft portion 4 of the hub material X2 is formed. In addition, lower mold 2
The upper surface 0 (corresponding to the surface sandwiching the plate portion) has a mold surface 2 shaped like the lower surface of the plate portion 3 of the hub material X2.
3 are formed, and the hub material X follows this mold surface shape.
2 is placed on the upper surface of the lower mold 20, the plate portion 3 is arranged in a direction crossing the bed 10 and the ram 11, and the shaft portion 4 is arranged along the bed 10 and the ram 11. .

The lower end of the lower mold 20 is fixed to an annular pedestal 24 held between the distal ends of the die cushion pins 13 and is driven by the air pressure (predetermined pressure) of the floating air cylinder 12. The whole is horizontally held at an upper point away from the bed 10 and held.

The state of the floating lower mold 20 is set to a standby position which is a work set / reset position, so that the hub material X2 before processing can be received and the hub material X2 after processing can be taken out.

With the support of the upper / lower dies 14, 20, the ram 11 is lowered (the ram 11 approaches the bed 10) after the hub material X2 is set, so that the hub material X2 is moved to the upper / lower dies 14, 20. At 20, it falls while being pinched from above and below. More specifically, the upper / lower dies 14 and 20 cover the outer periphery of the shaft portion 4 and substantially sandwich the entire plate portion 3 including the periphery of the shaft portion 4. The ram 11 sinks to the bottom dead center against the air pressure of the air cylinder 12.

It is to be noted that the lower mold 20
A guide pin 28a inserted into a guide hole 24a formed in the pedestal 24 for supporting
The hub material X2 is lowered by the lower mold 20 guided by a while maintaining a predetermined posture (horizontal state).

The restraint of the hub material X2 caused by the pinching at this time prevents unnecessary deformation of the outer surface even if an external force for punching is applied to the shaft portion 4.

Bed 1 with upper / lower dies 14 and 20
The ram 11 incorporates a punch 25 for punching the shaft 4 of the sandwiched hub material X2. The punch portion 25 includes a column-shaped counter punch 26 (equivalent to an inner punch) supported by the bed 10 and a ram 11.
A structure using a cylindrical upper punch 27 (corresponding to an outer punch) supported by the above is adopted.

That is, the counter punch 26 is located at the center of the upper surface of the bed 10 surrounded by the die cushion pins 13.
The lower mold 2 is mounted using the mounting seat 28 and the mounting base 29.
It stands up toward the through-hole 22 of zero.

More specifically, the counter punch 26 has an elongated rod portion 26a extending linearly from the mounting base 29 toward the through hole 22 of the lower die 20. At the distal end of the rod 26a, a tapered circular hole 26b is formed at the distal end of the through hole 22 of the lower die 20. is there.

The outer diameter of the front end of the hole 26b is set to a diameter corresponding to the inner diameter of the through hole 4a of the shaft portion 4 to be punched.
When the air cylinder 12 descends against the air pressure of the floating air cylinder 12 while being held between
b enters from the plate portion 3 toward the center of the shaft end of the base of the shaft portion 4 (hub material X2), and pushes out only the center portion corresponding to the through hole 4a.

The upper punch 27 is suspended inside the clip ring 16. Specifically, the upper punch 27
A structure is adopted in which a front end portion 30 of a short columnar portion having an outer diameter corresponding to the through hole diameter of the upper die 14, a flange portion 31 having a triangular cross section, and a columnar boss portion 32 are sequentially connected, and the outer shape is substantially umbrella-shaped. Has made. Inside the through hole 33 having a diameter corresponding to the diameter of the through hole 4a of the shaft portion 4 to be punched from the center of the shaft end of the tip portion 30 to the center of the shaft end of the boss portion 32 on the opposite side. Is formed.

The tip 30 of the upper mold 14 is
The boss portion 32 is slidably inserted into the through hole 17b formed in the center of the mounting seat 16a, and the flange portion 31 is vertically inserted into the clip ring 16. It is housed movably in the direction.

With this accommodation, the projection 16 c projecting inward of the clip ring 16 and the flange portion 31 are locked, and the upper punch 27 is suspended from the clip ring 16. Further, the flange portion 31 and the mounting seat 16 opposed thereto are provided.
A plurality of elastic members, for example, annular disc springs 34, are interposed between the upper punch 27a and the lower punch 27 to urge the suspended upper punch 27 downward to support the upper punch 27 so as to be elastically displaceable. Yes (floating support).

That is, the upper punch 27 is provided with a disc spring 34,
The upper punch 27 is supported by the ram 11 via a punch floating mechanism 35 having a suspension structure.
By this floating support, only the rough positioning of the tip of the upper punch 27 near the tip of the shaft portion 4 of the hub material X2 set in the lower die 20, the shaft of the shaft portion 4 is moved by the tip of the upper punch 27. While being in close contact with the end, the hub material X2 is lowered while being sandwiched between the upper die 14 and the lower die 20 (the elastic displacement of the disc spring 34 causes the tip of the upper punch 27 to move toward the shaft end of the shaft 4). From the contact with the upper mold 14 and the lower mold 20 until the hub material X2 is sandwiched between the upper mold 14 and the lower mold 20).

The shaft 4 formed at the tip of the upper punch 27
By restricting the outer peripheral portion of the shaft end, only a solid portion of the shaft portion 4 extruded by the counter punch 26 is sheared so that the shaft portion 4 can be punched.

A knock pin 37 is slidably inserted from the upper side into the through hole 33 of the upper punch 27 so that a chip 4c filling the through hole 33 of the upper punch 27 can be pushed out.

Specifically, a stopper 37a having a diameter larger than the through hole 33 is formed at the upper end of the knock pin 37, and the stopper 37a and the boss end of the upper punch 27 are locked. The entire knock pin is suspended in the through hole 33. Further, for example, of the frame members supporting the ram 11, a stopper member 38 is incorporated in a lower surface portion of the frame portion 11a above the knock pin 37. The stopper member 38 has an opening 11 b formed in the ram 11.
Is disposed so as to face the through hole 16b through which the stopper portion 37a of the knock pin 37 passes, and the ram 11 takes advantage of the behavior when returning from the bottom dead center to the top dead center.
The knock pin 37 pushed up by c is pushed down, and the chip 4c is discharged from the tip in the through hole 33.

On the other hand, a spray nozzle portion 39 for spraying a cooling liquid is formed in a lower die portion around the counter punch 26 so as to cool the punched portion 26b of the counter punch 26 after the punching process. It is.

More specifically, the opening edge of the lower surface of the lower die 20 facing the through hole 22 is cut out in a substantially hemispherical shape, and when the counter punch 26 is in a standby state, the cutout portion 20a extends from the cutout portion 26b to the vicinity of the cutout portion 26b. Is exposed. In the inner surface of the notch 20a surrounding the vicinity of the hole 26b, the hole 2
6, a plurality of spray nozzle holes 39a are formed.
The spray nozzle section 39 is used.

A cooling liquid supply device 40 for supplying a cooling liquid is connected to the spray nozzle hole 39a, for example, at a timing when the lower die 20 returns to the standby position after the hole punching process.
Each time the punching process is performed, the coolant is sprayed from the spray nozzle holes 39a to the punching portion 26b to cool the punching portion 26b which is heated by the punching process.

With such a structure, the existing press section 2d
By using hot forging, the hole of the shaft portion 4 of the hub material X2 can be satisfactorily drilled. This hole punching process is shown in FIGS.

Next, the operation of the hot forging apparatus 1 will be described with reference to FIGS. Now, NO. No. 1 press sections 2a-NO. 3, at 1100 ° C.
The hub material X1 of a predetermined shape heated to about 1250 ° C. is sequentially forged in a closed manner (forging to prevent generation of outer peripheral burrs using a mold covering the periphery of the hub material X1).
Is completed.

Then, the hub material X2 is sent to the press part 2d in a standby state at a feed part (not shown), and enters a hole punching step by hot forging. In the hole punching step, first, as shown in FIG. 2, a hub material X2 which is to be a work and is placed on the upper surface (mold surface) of the lower die 20 waiting at a predetermined position is formed. Go.

As a result, the hub blank X2 is set on the lower mold 20 with the plate portion 3 oriented in the horizontal direction and the shaft portion 4 oriented upward as indicated by the two-dot chain line in FIG. With this setting, the tip of the counter punch 26 in the hollow portion of the lower die 20 faces the center of the lower end surface of the shaft portion 4 to be drilled, and the upper punch 27 in the hollow portion of the upper die 14. The tip faces the outer peripheral portion of the upper end surface of the opposite shaft portion 4.

When the setting of the hub material X2 is completed, the press section 2d operates to lower the ram 11 waiting at the top dead center. As the ram 11 descends, the shaft portion 4 gradually enters the through hole 17 of the upper die 14 from the tip.

Then, first, the tip of the knock pin 37 protruding from the tip of the upper punch 27 comes into contact with the tip face of the shaft 4 and is pushed up. Subsequently, the distal end surface of the upper punch 27 comes into contact with the distal end surface of the shaft portion 4.

Here, since the upper punch 27 is supported by the disc spring 34 having an elastic force smaller than the air pressure (floating air cylinder 12) that floats the lower die 20, the lowering operation of the ram 11 is performed. As it proceeds, the disc spring 34 bends (compresses).

Then, the upper punch 27 does not descend and the upper die 1
Only 4 goes down. The upper mold 14 is used for the hub part X2.
As shown in FIG.
2 covers the outer peripheral surface of the shaft portion 4 and the upper side of the plate portion 3.

Here, since the upper die 14 is suspended from the ram 11 so as to be movable, the upper die 14 is in contact with the hub component X 2 and before the boss end of the upper punch 27 contacts the stopper ring 36. Continue to stagnate.

Next, when the boss end of the upper punch 27 abuts against the stopper ring 36, the ram pressure from the ram 11 is applied to the upper die 14 as shown in FIG.
2 is sandwiched between upper and lower dies 14, 20 from above and below.

Here, since the air pressure floating the lower mold 20 is lower than the ram pressure, the lower mold 20 is pushed down against the ram pressure. That is, the hub part X
2 sinks (push down) while being sandwiched between the upper and lower dies 14, 20.

By this behavior, hole punching by the counter punch 26 and the upper punch 27 is started. That is, since the counter punch 26 is fixed to the bed 10, as shown in FIG.
Of the shaft portion 4 toward the center of the shaft end of the shaft portion 4.

At this time, the outer surfaces of the plate portion 3 and the shaft portion 4 are restrained by the upper / lower dies 14 and 20 and the upper punch 27.
Is the shaft end opposite to the shaft portion 4, that is, the counter punch 26
3 (b), only the solid portion of the shaft portion 4 is pushed into the counter punch 26 while causing shearing, as shown in FIG. 3 (b).

Then, as shown in FIG. 4A, when the counter punch 26 is inserted until it penetrates the shaft 4, all the solid portions of the shaft 4 are pushed out. At this time, since the entire hub material X2 is constrained by the upper / lower dies 14, 20, the entire shaft portion 4 is punched without allowing the hub material X2 to be deformed.

Then, as the ram 11 reaches the bottom dead center, the hole punching process is completed. Subsequently, the ram 11 moves to the top dead center. As a result, the finished hub material X2 is
It is pushed up by the air pressure applied to the lower mold 20 while being sandwiched between the lower molds 14 and 20.

When the lower die 20 is pushed up to the standby position, only the lower die 20 stops at the standby position with the hub material X2 placed thereon, as shown in FIG. 4 (b). Then
The coolant supply device 40 is operated, the coolant is supplied from the device for a predetermined time, and the coolant is sprayed from each spray nozzle hole 39a toward the tip of the counter punch 26 to cool the counter punch 26. .

On the other hand, the upper mold 14 separated from the upper surface of the hub material X2 is lifted toward the upper dead center of the ram 11.
Here, in the inside of the through hole 33 of the upper punch 27, there remains the scrap 4c pushed out from the shaft portion 4 by the punching process, and the knock pin 37 inserted into the through hole 33 by the amount of the chip 4c is removed. It is pushing up.

For this reason, while the upper mold 14 is returning to the original standby position, the head (upper part) of the knock pin 37 contacts the stopper member 38 attached to the frame portion 11a as shown in FIG. I will contact you.

By this contact, only the movement of the knock pin 37 is restricted while the movement of the upper mold 14 remains unchanged, and FIG.
As shown in the figure, the chip 4c in the through hole 33 of the upper punch 27 is pushed out from the tip of the hole.

This pushing continues until the upper die 14 returns to the original standby position as shown in FIG.
The inside dust 4c is discharged to the outside. When the processed hub material X2 is removed from the lower die 20, the molding of the front hub Z is completed as shown in FIG. 6B.

As described above, the hot forging apparatus 1 that restrains the peripheral portion of the shaft portion 4 and punches the shaft portion 4 protruding from the plate portion 3 has a difficulty in the front hub Z and other parts that have been considered difficult. Even in the case of a work in which a shaft (column) protrudes from a thin plate, a hole can be punched in the shaft using the hot forging press part 2d without giving unnecessary deformation to the work. .

In particular, the plate portion 3 of the upper / lower dies 14, 20
Since the surface sandwiching the plate is formed in a shape following each part of the plate portion 3, the work is securely restrained and unnecessary deformation does not occur.

As a result, a good hole can be formed in the shaft portion without any trouble, so that the processing cost can be reduced.
Moreover, the hot forging of such holes is performed by pressing the upper / lower dies 14, 20 (pressing dies), the counter / upper punches 26, 27 (punch portions), and the knock pins 37 on the press portion 2d of the existing hot forging device 1. Existing press part 2d
, Holes can be easily removed by hot forging.

In addition, following the process of forming the outer shape by hot forging as in the above-described embodiment, the process can be directly transferred to hot forging for punching, and the production efficiency is excellent.
In addition, since the upper punch 27 (outer punch) is floatingly supported by the ram 11, the hub material X2 is sandwiched between the upper die 14 and the lower die 20 after the upper punch 27 abuts on the shaft end of the shaft portion 4. The upper punch 27 can be pressed down while sandwiching the hub material X2 (work) in a predetermined position while the rough upper punch 27 is positioned.

A counter punch 2 heated by punching holes
6 is cooled by the cooling liquid, the counter punch 26 can be protected from heat damage, and highly reliable hole punching can be realized. In the embodiment, the case where the front hub is formed is described as an example. However, the present invention is not limited to this. Needless to say, this can also be applied.

Further, in one embodiment, the present invention is applied to a blanking press portion in a hot forging device for forming a component outer shape. However, a hot forging device separate from the hot forging device for forming a component outer shape is used. The present invention may be applied to a press section of a forging device.

[0075]

As described above, according to the first aspect of the present invention, the plate portion is sandwiched from both sides and restrained, and the pillar portion restrained together with the plate portion is punched. Although hot forging is performed, the hole protruding from the plate portion can be formed without deforming the plate portion and the column portion.

Further, it is only necessary to provide a holding die, a punch, and a knock pin in the press section of the existing hot forging apparatus, and the existing press section can be used to easily punch holes in the column section by hot forging. It can be carried out.

According to the invention described in claim 2, according to claim 1
In addition to the effect of the above, the deformation of the work at the time of punching can be reliably suppressed. According to the third aspect of the present invention, in addition to the effects of the first and second aspects, the tip of the outer punch is brought into close contact with the shaft end of the pillar portion and is suppressed to a predetermined level while rough positioning of the outer punch is performed. The work can be sunk while sandwiching it with the mold. According to the fourth aspect of the invention, in addition to the effects of the first, second, and second aspects, the inner punch heated by punching can be protected from heat damage.

[Brief description of the drawings]

FIG. 1 is a view for explaining a structure for punching holes in a hot forging apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view for explaining the structure of a hole-punched portion for performing the hole-punching.

FIG. 3 is a cross-sectional view for explaining an operation of forming a through-hole in a shaft portion of the front hub in the hole punching section.

FIG. 4 is a cross-sectional view for explaining a step of a hole punching section following the operation.

FIG. 5 is a cross-sectional view for explaining a step of discharging chips after the hole punching process.

FIG. 6 is a cross-sectional view for explaining a state where the same chip is discharged.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hot forging apparatus 2d ... Press part 10 ... Bed 11 ... Ram 12 ... Floating air cylinder (cushion mechanism) 13 ... Die cushion pin (cushion mechanism) 14, 20 ... Upper mold, lower mold (a pair of holding molds) 26 ... Counter Punch (Inner Punch) 27 ... Upper Punch (Outer Punch) 35 ... Punch Floating Mechanism 37 ... Knock Pin 38 ... Stopper Member 39 ... Spray Nozzle Part 40 ... Cooling Liquid Supply Device X2 ... Hub Material (Work).

Claims (4)

[Claims] 1. A bed having a cushion mechanism and supporting one mold, and a ram supporting the other mold and moving in a direction of coming and coming from the bed, wherein a plate is provided between both molds. A press portion on which a workpiece having a portion and a column portion formed thereon is placed; and one of the dies is provided in a state of being supported by the cushion mechanism and floating from the bed, and the other is supported by the ram. A pair of holding molds that move so as to sandwich the work by both molds as the ram approaches the bed; and a center end of a column of the work that is supported by the bed and has a tip end from one of the holding molds. An inner punch supported by the ram and an outer punch whose tip end faces the shaft end of the column of the work from the other holding mold, and the holding mold moves the work by approaching the ram. Sandwiched A punching unit for punching and shearing the central or the column part, hot forging apparatus, wherein a slug in the outer punch completing the punching was and a knock pin pressing out within the outer punch. 2. The hot forging apparatus according to claim 1, wherein the pressing die has a surface sandwiching the plate portion formed by a die surface following the shape of each portion of the plate portion. 3. The hot forging apparatus according to claim 1, wherein the outer punch is supported by being floated from the ram via a punch cushion mechanism. 4. The spray nozzle according to claim 1, further comprising a spray nozzle around the inner punch for spraying a cooling liquid toward a tip end of the inner punch. Hot forging equipment.