KR20080011299A - Punching method and punching device - Google Patents

Abstract

A punching method and a punching device capable of punching with high yield of material and low molding load and preventing underfill from occurring. The punching method comprises a step for pushing open the predicted punched part (2) of a raw material (1) in such a state that an unfilled part (M) remains in a cavity (12) by pressing the predicted punched part (2) of the raw material (1) disposed in the cavity (12) of a closed die (11) from both sides of the predicted punched part (2) by a pair of large and small diameter punches (15) and (13) with different diameters and disposed oppositely to each other, a step for passing the small diameter punch (13) through the predicted punched part (2) of the raw material (1) while or after relieving the pressing of the large diameter punch (15) against the predicted punched part (2) of the raw material (1), and a step for passing the large diameter punch (15) through the predicted punched part (2) of the raw material (1) while or after extracting the small diameter punch (13) passed through the predicted punched part (2) of the raw material (1) from the predicted punched part (2).

Description

Hole Forming Processing Method and Hole Forming Processing Equipment {PUNCHING METHOD AND PUNCHING DEVICE}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a hole forming processing method and a hole forming processing apparatus used for the production of hole forming products such as arms for vehicles (such as automobiles and railroad cars) and cone rods.

Conventionally, when manufacturing a hole-forming product by forging, the hole-forming portion of the material is first thinly formed without performing the hole-forming process directly on the hole-forming portion of the material due to die life or safety problems. It is common to carry out shaping | molding, and to carry out trimming for removing a flash part continuously.

Further, in Japanese Unexamined Patent Application Publication No. 11-147157, in one press cycle, the preform is roughly molded in the cavity (molding space) of the occlusion die, and subsequently the hole formation scheduled portion is flashed thinly by a punch inserted into the occlusion die. The method of punching out and removing a flash part with the said punch after leaving it forcibly pressurizing is disclosed (refer patent document 1).

Patent Document 1: Japanese Patent Application Laid-Open No. 11-147157

However, in the conventional hole forming method, since the flash portion is punched out after the closed forging, a high molding load is required in order to prevent the occurrence of tissue defects during forging, and the material yield is low.

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical background, and its object is to provide a hole forming processing method capable of performing hole forming processing with a high material yield and deterioration, and preventing the occurrence of tissue defects, thereby obtained. It is providing the hole forming product and the hole forming processing apparatus used for the said hole forming processing method.

The present invention provides the following means.

[1] A hole is formed by pressing a hole forming scheduled portion of a material disposed in a cavity of a closed die from a pair of large diameter and small diameter punches having different diameters and facing each other from opposite sides between the hole forming scheduled portions. Pressing and expanding the formation scheduled portion in a state where an unfilled portion remains in the cavity;

A step of passing the small diameter punch through the hole formation scheduled portion of the material after releasing or releasing the pressure to the material hole formation scheduled portion by the large diameter punch;

And a step of causing the large diameter punch to pass through the hole forming scheduled portion of the raw material while the small diameter punch penetrated from the hole forming scheduled portion or after being ejected from the hole forming scheduled portion of the raw material. .

[2] The tip of the small-diameter punch is formed into a thin end, and the peripheral surface of the tip of the small-diameter punch is formed of a plurality of tapered surfaces arranged so that the taper angle gradually decreases toward the distal end of the small-diameter punch. The hole formation processing method of the preceding paragraph.

[3] When the number of steps of the tapered surface forming the peripheral surface of the tip of the small-diameter punch is set to N stages (where N? 2),

The tip end portion of the large diameter punch is formed in a thin end shape, and the peripheral surface of the front end portion of the large diameter punch is formed with a single taper surface smaller than N, which is arranged so that the taper angle gradually decreases toward the tip direction of the large diameter punch. Or the hole forming processing method according to the above item 2, which is formed by a tapered surface in one step.

[4] The closing die is provided with a punch insertion hole for each punch penetrating through and communicating with the cavity;

In the state where each punch is penetrated into the corresponding punch insertion hole, respectively, a gap in which excess material of the hole formation scheduled portion of the material flows in from the cavity between the peripheral surface of the punch and the peripheral surface of the punch insertion through hole. The hole forming processing method in any one of said claim | item 1-3 which is formed.

[5] The hole forming processing method according to the above item 4, wherein a weir portion that prevents the excess material flowing into the gap from being discharged to the outer peripheral surface of the punch is provided in a bulging shape in the radially outer side of the punch.

[6] In the above-mentioned pressing enlargement step, in the preceding paragraphs 1 to 5, the hole forming scheduled portions of the raw materials are pressed with both punches so as not to contact the ends of the punches from opposite sides between the hole forming scheduled portions of the raw materials. The hole formation processing method in any one of Claims.

[7] The material is rod-shaped, and a predetermined portion in the axial direction of the material is a hole forming scheduled portion,

And a step of expanding the diameter of the hole forming scheduled portion of the material in advance by a swaging device before the pressing expanding step,

The swaging device includes a guide having a fixed die which is continuously installed on the blocking die and fixes the material, an insertion hole for inserting and holding the hole formation scheduled portion of the material in a buckling-stopped state, and a pressing punch, A pair of diameter expansion suppression protrusions projecting in the axial direction of the guide are integrally provided at portions opposite to each other with an insertion through hole interposed between the guide portion,

In the diameter-expansion step, the hole formation scheduled portion of the material fixed to the fixed die is disposed in the cavity, the hole formation scheduled portion of the material is inserted and held in the insertion through hole of the guide, and the pressure punch is subsequently moved to press the pressure. By moving the guide in the direction opposite to the movement direction of the pressing punch while pressing the hole forming scheduled portion of the raw material with the punch, the hole forming scheduled portion of the raw material exposed between the tip end portion of the guide and the fixed die is formed. The diameter is expanded in the cavity while the diameter expansion is suppressed with respect to the contact portion with the guide protrusion,

In the pressure expanding step, any one of the preceding paragraphs 1 to 6, which presses from both sides of the diameter-expansion inhibiting direction of the hole-forming scheduled portion by the guide both projections, with both punches, while the hole-expansion scheduled portion of the diameter-expanded material is arranged in the cavity. The hole forming processing method according to claim 1.

[8] A hole-forming product obtained by the hole-forming method according to any one of the above 1 to 7.

[9] a closed die having a cavity,

A pair of large-diameter and small-diameter punches, which are arranged opposite to each other on opposite sides with the hole forming scheduled portions of the raw material in the state arranged in the cavity, and differ in diameter from each other,

Pressing the hole forming scheduled portion of the material placed in the cavity of the closed die from both sides with both punches and the hole forming scheduled portion is pressed to enlarge the hole forming scheduled portion, and then to the material hole forming scheduled portion by the large diameter punch. After releasing or releasing the pressure, the small diameter punch is made to pass through the hole formation scheduled portion of the raw material, and the small diameter punch which is subsequently penetrated through the hole formation scheduled portion of the raw material is extracted or extracted from the hole formation scheduled portion. The hole forming processing apparatus which consists of making a punch penetrate the hole formation plan part of a raw material.

[10] The distal end portion of the small diameter punch is formed into a thin end, and the peripheral surface of the distal end portion of the small diameter punch is formed of a plurality of tapered surfaces arranged so that the taper angle gradually decreases toward the distal direction of the small diameter punch. The hole forming processing apparatus according to the preceding paragraph.

[11] When the number of steps of the tapered surface forming the peripheral surface of the tip of the small diameter punch is set to N stages (where N ≥ 2),

The tip end portion of the large diameter punch is formed in a thin end shape, and the peripheral surface thereof is formed with a single taper surface smaller than N, arranged so as to gradually decrease the taper angle toward the leading direction of the large diameter punch, or 1 The hole forming processing apparatus according to the above item 10, which is formed by the tapered surface of the stage.

[12] The blocking die is provided with a punch insertion hole for inserting each punch through and communicating with the cavity.

In the state where each punch is penetrated into the corresponding punch insertion hole, respectively, a gap is formed between the periphery of the punch and the periphery of the punch insertion hole so that the surplus material of the hole formation scheduled portion of the material flows in from the cavity. The hole forming processing apparatus according to the preceding claim 9 to 11.

[13] The hole forming apparatus according to the item 12, wherein a weir portion that prevents the excess material introduced into the gap from being discharged to the outer peripheral surface of the punch is provided in a bulging shape in the radially outer side of the punch.

[14] The material is rod-shaped, and a predetermined portion in the axial direction of the material is a hole forming scheduled portion,

Before the pressure expansion of the hole formation scheduled portion of the raw material, a swaging device for diameter expansion of the hole formation scheduled portion of the raw material,

The swaging device includes a guide having a fixed die which is continuously installed on the blocking die and fixes the material, an insertion hole for inserting and holding the hole formation scheduled portion of the material in a buckling-stopped state, and inserted into the insertion through hole of the guide. And a punch drive device for pressing the hole forming scheduled portion of the pierced material in the axial direction, and a punch driving device for moving the guide in a direction opposite to the movement direction of the pressure punch, and at the same time between the insertion through hole of the tip of the guide. A pair of diameter enlargement suppression protrusions which protrude in the axial direction of the guide are integrally provided at portions opposite to each other,

The projection part of the guide which suppresses the diameter expansion with respect to the contact part with the projection part of a hole formation plan part by a part of the circumferential surface of a hole formation plan part contacting the side surface of a projection part at the time of diameter expansion of the hole formation plan part of a raw material. The hole forming processing apparatus in any one of 13.

The present invention has the following effects.

In the invention of [1], the hole forming scheduled portion of the raw material disposed in the cavity of the closed die is pressed from the opposite sides with the hole forming scheduled portion by a pair of large diameter and small diameter punches, so that the hole forming scheduled portion is unfilled in the cavity. Since the pressure is enlarged in the state in which all remain | survive, the hole formation scheduled part can be expanded in the cavity in the fall.

In addition, since the small diameter hole is formed in the hole formation scheduled portion by passing the small diameter punch through the hole formation scheduled portion of the raw material, the hole can be formed with a relatively low load. Further, by the penetrating operation of the small-diameter punch, the material of the hole formation scheduled portion of the raw material can be filled in the front side portion in the penetrating direction of the small-diameter punch in the unfilled portion in the cavity.

In addition, the hole of the small diameter is enlarged by penetrating the large-diameter punch in the hole formation scheduled portion of the material in which the hole of the small diameter is formed in this way, so that a large diameter hole is formed in the hole formation scheduled portion, thereby forming a hole with a relatively low load. Can be. Moreover, the material of the hole formation scheduled part of a raw material can be filled in the front side part of the large diameter punch penetrating direction in the unfilled part in a cavity by this penetrating operation | movement of a large diameter punch. Therefore, almost all of the unfilled portion in the cavity disappears and the material is filled in the entire cavity, thereby preventing the occurrence of tissue defects.

In addition, since the hole formation processing method of this invention is not a method of opening a hole by punching out material of the hole formation plan part of a raw material, material yield is high.

In the invention of [2], since the distal end portion of the small diameter punch is formed in the shape of a thin tip, the small diameter punch can be penetrated into the hole formation scheduled portion of the raw material with a low load. Further, since the peripheral surface of the tip portion of the small-diameter punch is formed of a plurality of tapered surfaces arranged so that the taper angle gradually decreases toward the tip direction of the small-diameter punch, the taper angle of the plurality of stages of the small-diameter punch is set by The molding load can be adjusted to a predetermined value. In addition, the hole formation scheduled portion of the raw material can be effectively enlarged to the radially outer side of the small-diameter punch by the penetrating operation of the small-diameter punch, so that the portion on the front side in the penetrating direction of the small-diameter punch in the unfilled portion in the cavity can be expanded. The material of the hole formation scheduled portion of the material can be reliably filled.

In the invention of [3], since the distal end portion of the large diameter punch is formed in a thin tip shape, the large diameter punch can be penetrated to the hole formation scheduled portion of the raw material under a low load. Further, the peripheral surface of the tip portion of the large diameter punch is formed of a single taper surface smaller than N, or is formed with a taper surface of one stage, which is arranged so that the taper angle gradually decreases toward the tip direction of the large diameter punch. Therefore, the molding load can be adjusted to a predetermined value. In addition, the hole formation scheduled portion of the raw material can be effectively enlarged to the radially outer side of the large diameter punch by the penetrating operation of the large diameter punch, so that the front side portion of the large diameter punch in the through direction of the large diameter punch in the unfilled portion in the cavity can be effectively expanded. The material of the hole formation scheduled portion of the material can be reliably filled.

In the invention of [4], in the state where each punch is inserted into the corresponding punch insertion through hole, the excess material of the hole formation scheduled portion of the material is located between the peripheral surface of the punch and the peripheral surface of the punch insertion through hole. Since the gap which flows in from the inside is formed, the material of the hole formation plan part of a raw material can be filled in the unfilled part in a cavity with a comparatively low load.

In the invention of [5], it is possible to prevent the excess material flowing into the gap from being discharged to the outside by the weir.

In the invention of [6], it is possible to prevent damage or damage to the punch tip, which may occur due to contact between the tips of the two punches.

In the invention of [7], when the hole forming processing is performed on the hole forming scheduled portion after the diameter of the hole forming scheduled portion of the raw material is enlarged in advance, such processing can be performed efficiently.

In the invention of [8], it is possible to provide a hole-forming product in which no tissue defect is generated or hardly occurring.

In the invention of [9]-[14], the hole forming apparatus which can be used suitably for the hole forming processing method which concerns on this invention can be provided.

1 is an exploded perspective view of a hole forming processing apparatus according to an embodiment of the present invention.

Fig. 2 is a sectional perspective view of the hole forming processing apparatus in a state before the diameter of the hole forming scheduled portion of the raw material is enlarged by the hole forming processing apparatus.

3 is a horizontal sectional view of the hole forming processing apparatus in the state of FIG.

4 is a cross-sectional view taken along the line A-A in FIG.

5 is a cross-sectional perspective view of the hole forming processing apparatus in a state in which the hole forming scheduled portion of the raw material is expanded in diameter by the hole forming processing apparatus.

FIG. 6 is a horizontal sectional view of the hole forming processing apparatus in the state of FIG. 5. FIG.

Fig. 7 is a sectional perspective view of the hole forming processing apparatus in a state after the diameter of the hole forming scheduled portion of the raw material is enlarged by the hole forming processing apparatus.

8 is a horizontal sectional view of the hole forming processing apparatus in the state shown in FIG.

9 is a cross-sectional view taken along the line B-B in FIG.

10 is a cross-sectional view of the hole forming processing apparatus in a state in which the hole forming scheduled portion of the raw material is enlarged by the hole forming processing apparatus.

Fig. 11 is a cross-sectional view of the hole forming apparatus in a state in which a small-diameter punch is made to pass through a hole forming example of the raw material by the hole forming apparatus.

Fig. 12 is a sectional view of the hole forming processing apparatus in a state where the large diameter punch penetrates the hole forming scheduled portion of the raw material by the hole forming processing apparatus.

Fig. 13 is a perspective view of a hole-forming product obtained by the above-mentioned hole forming processing apparatus.

[Description of the code]

1: material

2: hole forming part

3: hole

6: hole forming product (preform)

10: hole forming processing equipment

11: occlusion die

12: cavity

13: small diameter punch

14: tip

15: large diameter punch

16: tip

17: Punch Insert Through Hole

18: gap

19: slide groove

20: swaging device

21: fixed die

22: guide

23: insertion through hole

24: protrusion for preventing diameter expansion

24a: side

25: pressurized punch

27: direction of movement of the guide

28: moving direction of the pressure punch

30: punch drive device

32: guide driving device

33: pressure punch drive device

M: Unfilled part

Next, one Embodiment of this invention is described below with reference to drawings.

In Fig. 1, reference numeral 10 denotes a hole forming processing apparatus according to the present embodiment, and reference numeral 1 denotes a raw material. In Fig. 13, reference numeral 6 denotes a hole forming product (hole forming product) manufactured by the hole forming processing apparatus 1. This hole formation product 6 is used as a preform for manufacturing vehicle arms, such as an automobile and a railroad car, for example.

As shown in Fig. 1, the raw material 1 is in the form of a straight rod, and is made of, for example, aluminum (including its alloy. The same below). The cross-sectional shape of the raw material 1 is circular, and the cross-sectional area of the raw material 1 is set constant in the axial direction.

In addition, in this invention, the material of the raw material 1 is not limited to aluminum, For example, metal, such as brass, copper, stainless steel, may be sufficient and plastic may be sufficient as it. In addition, the cross-sectional shape of the raw material 1 is not limited to circular shape, Polygonal shape, such as square shape and hexagon shape, may be sufficient.

The hole forming scheduled portions 2 of the raw material 1 are located at both axial side portions of the raw material 1, and in detail, are located at both ends of the raw material 1, that is, at both ends of the raw material 1; Each consists of the hole formation plan part 2, respectively. Then, after each hole formation scheduled portion 2 of the raw material 1 is enlarged in a substantially disk shape, the hole formation processing is performed in the hole enlargement scheduled portion 2 which is enlarged in diameter, thereby forming the hole shown in FIG. A product 6 can be obtained.

In this hole forming product 6, the portion where the hole forming processing is performed, that is, the hole forming processing portion 5 corresponds to the connecting portion connected to the other member of the vehicle arm, and the hole forming processing portion 5 The formed hole 3 corresponds to a bushing holding hole, for example. This hole 3 penetrates in the thickness direction of the hole formation plan part 2 which diameter-expanded to disk shape, and its cross-sectional shape is circular shape.

In this hole formation product 6, the diameter of each hole formation process part 5 is 70 mm, the thickness is 24 mm, the diameter of the hole 3 is 30 mm, and both hole formation process parts 5, for example. The length between (5) is 300 mm. In addition, the diameter of the raw material 1 is 18 mm. However, in this invention, the dimension of each site | part of the hole formation product 6 and the diameter of the raw material 1 are not limited to the dimension mentioned above. For example, the dimensions of each part and the diameter of the material 1 can be set so as to achieve the object of the present invention in accordance with the manufacture of the hole-forming product 6 such as an arm for a vehicle (such as a car or a railroad car) or a cone rod. have.

The hole formation processing apparatus 10 of this embodiment is for forming the hole 3 in the hole formation plan part 2 of the raw material 1, and as shown in FIG. ), A pair of two sets of punches 13 and 15 (i.e., hole forming punches), a punch drive device 30 for moving each punch 13 and 15, and a swaging device 20. Doing.

The closing die 11 has two cavities 12 and 12 which form each hole formation scheduled portion 2 of the raw material 1 into a set shape (that is, a disc shape). Both cavities 12 and 12 are arranged spaced apart from each other in the axial direction of the closing die 11. Moreover, this blocking die 11 is divided into two top and bottom along the axial direction.

In the cavity 12 of the blocking die 11, the hole formation scheduled portion 2 of the raw material 1 is disposed.

The pair of punches 13 and 15 are each formed in a cross-sectional circular shape. Each punch 13 and 15 is for forming the hole 3 in the hole formation plan part 2 to which the raw material 1 corresponds. Both punches 13 and 15 are different in diameter from each other. In addition, the punches 13 and 15 are arranged to face each other on the opposite sides with the hole forming scheduled portion 2 of the raw material 1 disposed in the cavity 12 therebetween. In other words, both punches 13 and 15 are arranged opposite to each other on the opposite sides with the cavity 12 interposed therebetween. In this embodiment, both punches 13 and 15 are arranged to face up and down.

In addition, in this specification, the larger diameter among the punches 13 and 15 is called "large diameter punch 15", and the smaller diameter is called "small diameter punch 13". .

The diameter of the large diameter punch 15 is set to the same dimension as the diameter of the desired hole 3. On the other hand, the diameter of the small-diameter punch 13 is set smaller than the diameter of the large-diameter punch 15, and the ability of the punch drive device 30 to drive the small-diameter punch 13 and the penetration into the hole formation scheduled portion 2 is reduced. It determines by calculation according to various conditions, such as required stroke of the small diameter punch 13, the taper angle of the peripheral surface of the front-end | tip part of the small diameter punch 13, etc. For example, the diameter of the small diameter punch 13 is set in the range of 0.4 times or more and less than 1 times (preferably 0.66 to 0.95 times) of the diameter of the large diameter punch 15. As shown in FIG. However, in this invention, the diameter of the small diameter punch 13 is not limited to what is this range.

The tip portion 14 of the small-diameter punch 13 is formed in a thin end shape as shown in FIG. Further, the peripheral surface of the distal end portion 14 of the small diameter punch 13 has a plurality of tapered surfaces arranged in such a manner that the taper angles α1 and α2 gradually decrease toward the distal direction of the small diameter punch 13 ( 14a) and 14b). In the present embodiment, the number of stages of the tapered surfaces 14a and 14b is two stages. Therefore, among the taper angles α1 (α2) of these tapered surfaces 14a and 14b, the taper angle α1 of the first stage and the taper angle α2 of the second stage are counted from the tip of the small-diameter punch 13. Is set to alpha 1 <alpha 2.

The tip end portion 16 of the large diameter punch 15 is formed in a thin end shape. For convenience of explanation, the number of stages of the tapered surfaces 14a and 14b forming the peripheral surface of the tip portion 14 of the small-diameter punch 13 is referred to as N stages (where N? 2). In this case, the peripheral surface of the distal end portion 16 of the large diameter punch 15 has a single taper surface smaller than N arranged in such a manner that the taper angle gradually decreases toward the distal direction of the large diameter punch 15 ( 16a). In this embodiment, since N = 2, the circumferential surface of the tip portion 16 of the large-diameter punch 15 is formed of one-step tapered surface 16a. (β1) is the taper angle of this tapered surface 16a.

Moreover, in this invention, it is not limited to what is N = 2, What is necessary is just N = 2 or more, for example, N = 3, 4, or 5 may be sufficient. In addition, the number of stages of the tapered surface 16a which forms the peripheral surface of the front-end | tip part 16 of the large diameter punch 15 is not limited to one stage, What is necessary is just a stage smaller than N, for example, when N = 3 May be 1 step or 2 steps, in the case of N = 4, 1 to 3 steps may be sufficient, and in the case of N = 5 steps, 1 to 4 steps may be sufficient.

Here, in the present specification, the taper angles α1 (α2) (β1) of the tapered surfaces 14a, 14b, and 16a refer to the tapered surfaces 14a (with respect to the axes of the punches 13 and 15). 14b) refers to the angle formed by 16a.

Moreover, the front end surface of each punch 13 and 15 is formed in flat shape. However, in this invention, the front end surface of each punch 13 and 15 is not limited to what is formed in flat shape, For example, you may be curved and formed in convex surface shape.

In addition, the punches 13 and 15 are connected to the punch drive device 30, respectively. Then, by operating the punch drive device 30, the corresponding punch 13 and 15 can be moved so as to be able to move forward and backward with respect to the cavity 12, that is, the punch 13 and 15 are moved. And move out into the cavity 12 or exit out of the cavity 12.

The punch drive device 30 is constituted by applying a driving force to the punches 13 and 15 by a mechanical cam using a press, a fluid pressure (hydraulic pressure, gas pressure, etc.), an electric motor, or the like.

Each of the punches 13 and 15 is inserted into and communicated with the cavity 12 to portions on opposite sides (up and down sides in the present embodiment) with the cavity 12 in the blocking die 11 interposed therebetween. Punch insertion through holes 17 and 17 are provided. Then, the punches 13 and 15 are inserted and disposed in the corresponding punch insertion holes 17 and 17 so as to be movable in the vertical direction. In this state, as shown in Fig. 4, each punch 13, 15 between the periphery of each punch 13, 15 and the periphery of each punch insertion hole 17, 17. The gaps 18 and 18 (so-called gaps between the punch 13 and 15 and the punch insertion holes 17 and 17) are formed over the entire circumference of the circumferential direction. In this gap 18, surplus material (so-called flash portion) 2a of the hole formation scheduled portion 2 of the raw material 1 flows into the cavity 12 (see Figs. 11 and 12). Moreover, the surplus material 2 which flowed into this clearance gap 18 remains in the periphery of the hole 3 as a burr.

Further, on the circumferential surface of each punch 13, 15, weirs 13a, 15b which prevent the excess material 2a flowing into the gap 18 from being discharged to the outside of the blocking die 11 are provided. A radially outer side of the punches 13 and 15 is integrally formed over the entire circumference of the punches 13 and 15 in a bulging shape.

The swaging device 20 is intended to simultaneously enlarge the diameters of the two holes forming scheduled portions 2 and 2 of the raw material 1.

As shown in Figs. 1 to 3, the swaging device 20 is fixed to the fixed die 21 and the two guides 22, 22, two pressure punches 25 and 25 (i.e., mounting punches), two guide drive devices 32 and 32, and two pressure punch drive devices 33 and 33; have.

The stationary die 21 consists of a site | part between both cavities 12 and 12 of the blocking die 11, and is formed integrally and continuously provided in the blocking die 11. As shown in FIG. In addition, the fixed die 21 is divided into two upper and lower sides along the axial direction. Then, the divided pieces of the blocking die 11 and the fixed die 21 are held together by a die holding member (not shown) in an assembled state, whereby the blocking die 11 and the fixed die 21 are separated. Is unintentionally disassembled. In the present invention, the fixed die 21 may be a member separate from the blocking die 11.

The fixed die 21 is for fixing the raw material 1 so that the raw material 1 does not move unintentionally in the axial direction when the diameter is expanded. The fixing die 21 has a fixing hole 21a for fixing the raw material, in which an axial middle portion 4 as a non-hole forming scheduled portion of the raw material 1 is inserted and fixed. It extends in the axial direction of) and is connected to both cavities 12 and 12, and is provided. By inserting the axial middle part 4 of the raw material 1 into the insert hole 21a for fixing the raw material, the raw material 1 is fixed so as not to move in the axial direction and the raw material 1 is Diameter expansion and buckling of the axial middle part 4 are prevented.

The two guides 22 and 22 have the same configuration. Each guide 22 has an insertion hole 23 which penetrates and holds a corresponding hole formation scheduled portion 2 of the raw material 1 in a buckling-stopped state. This insertion hole 23 extends in the axial direction of the guide 20 and is provided through the guide 20. The diameter of this insertion hole 23 is set to the dimension which can slidably insert the hole formation plan part 2 of the raw material 1 into the said insertion hole 23 in a suitable state, and to be able to slide in an axial direction, have.

Moreover, the pair of diameter expansion suppression protrusions 24 and 24 which protrude in the axial direction of the guide 22 in the mutually opposing site | part which inserted the insertion through-hole 23 between the front-end | tip part of the guide 22, respectively. Is integrally provided, and both the protrusions 24 and 24 are integrally moved with the guide 22 with movement to the guide 22. In addition, a part of the peripheral surface of the hole formation plan part 2 of the raw material 1 in the state which penetrated in the insertion through hole 23 of the guide 22 at the time of the diameter expansion of the hole formation plan part 2 is expanded. It is made to contact the side surface 24a toward the insertion through-hole 23 side of each projection part 24, and diameter expansion is suppressed with respect to the contact part with the projection part 24 of the hole formation plan part 2 by this.

On the other hand, the slide groove part 19 extended in the axial direction of the blocking die 11 is provided in the upper and lower surfaces of the cavity 12 of the closing die 11, respectively. The projection 24 of the guide 22 is slidably inserted into the slide groove 19 in the axial direction of the closing die 16.

Moreover, the side surface 24a of the protrusion part 24 of the guide 22 which a part of the circumferential surface of the hole formation plan part 2 of the raw material 1 contacts is the hole formation example in which the diameter of the raw material 1 expanded. It is formed in the surface corresponding to the shape of the peripheral surface of the government part 2. And in the state where the protrusion part 24 was inserted in the slide groove part 19, the side surface 24a of the protrusion part 24 is made to continue to the same height on the upper surface or lower surface of the cavity 12. As shown in FIG. Moreover, in this embodiment, the side surface 24a of this protrusion part 24 is formed in flat shape corresponding to the circular surface of the both sides of the thickness direction of the hole formation plan part 2 which enlarged in diameter substantially disk shape.

Moreover, each guide 22 is divided | segmented into two top and bottom by the division surface which terminates the insertion through-hole 23. As shown in FIG. And the divided pieces of each guide 22 are hold | maintained by the guide holding member (not shown) mutually assembled, and the guide 22 consists of not disassembling unintentionally by this.

Each press punch 25 is for pressing the corresponding hole formation plan part 2 of the raw material 1 to an axial direction. Both press punches 25 and 25 are disposed opposite to each other on both sides of the material 1 in the axial direction.

Each press punch drive apparatus 33 moves each press punch 25 in the axial direction of the raw material 1, and presses the hole formation plan part 2 of the raw material 1 to the press punch 25, respectively. It is to give a driving force. Each of these pressure punch drive devices 33 is connected to a corresponding pressure punch 25. The pressure punch drive device 33 is configured to apply a driving force to the pressure punch 25 by a mechanical cam using a press, a fluid pressure (hydraulic pressure, gas pressure, etc.), an electric motor, or the like.

Each guide drive device 32 moves each guide 22 to the moving direction 28 of the corresponding press punch 25 (that is, the press direction to the material hole formation plan part 2 by the press punch 25). Is to move in the opposite direction 27 (see Fig. 6). Each of the guide drive devices 32 is connected to the corresponding guide 22. The guide drive device 32 consists of applying a driving force to the guide 22 by a mechanical cam using a press, fluid pressure (hydraulic pressure, gas pressure, etc.), an electric motor, a spring, or the like.

Next, the hole forming processing method using the hole forming processing apparatus 10 will be described below.

First, as shown in FIGS. 2 to 7, each hole formation scheduled portion 2 of the raw material 1 is enlarged in diameter by the swaging device 20 of the hole forming processing device 10 (diameter enlargement). fair]. In this embodiment, both hole formation plan parts 2 and 2 of the raw material 1 are simultaneously expanded in diameter.

This diameter expansion method is described below.

As shown in FIGS. 2-4, the axial middle part 4 which is a non-hole formation scheduled part of the raw material 1 is inserted into the raw material fixing insertion hole 21a of the fixed die 21, The material 1 is fixed to the stationary die 21 so that (1) does not move unintentionally in the axial direction, and each hole formation scheduled portion 2 of the material 1 is respectively provided in the corresponding cavity 12. To place. In this embodiment, the hole formation plan part 2 of the raw material 1 is arrange | positioned in the cavity 12 in penetrating shape. Therefore, only the axial direction intermediate part side part in the hole formation plan part 2 of the raw material 1 is arrange | positioned in the cavity 12, and the end side part of the hole formation plan part 2 protrudes from the cavity 12. Is placed in a closed state.

Moreover, each hole formation plan part 2 of the raw material 1 is inserted into the insertion hole 23 of the corresponding guide 22, respectively, and this makes each hole penetration plan part 2 into a buckling stop state. Hold. Moreover, the projection part 24 of the guide 22 corresponding to each slide groove part 19 of the blocking die 11 is inserted. In this state, the mutually opposite parts of the peripheral surface of each hole formation plan part 2 of the raw material 1 contact the side surfaces 24a and 24a of both projections 24 and 24 of the guide 22. Doing.

Subsequently, as shown in FIG. 5 and FIG. 6, by simultaneously operating both pressure punch drive devices 33 and 33, both pressure punch 25 and 25 are moved simultaneously, and both holes of the material 1 Both guides 22 and 22 by simultaneously operating both guide drive devices 32 and 32 while simultaneously pressing the formation scheduled portions 2 and 2 in the axial direction with corresponding pressure punches 25 and 25 respectively. ) Are simultaneously moved in the opposite direction 27 to the moving direction 28 of the corresponding pressing punches 25 and 25, respectively. Thereby, a part of the peripheral surface of the hole formation plan part 2 of the raw material 1 exposed between the front-end | tip part of each guide 22 and the stationary die 21 is the both projection part 24 of the guide 22 ( By contacting the side surfaces 24a and 24a of 24, the hole formation scheduled portion 2 in a state in which diameter enlargement is suppressed with respect to the contact portion with the guide projections 24 and 24a of the hole formation scheduled portion 2 is prevented. (In detail, the part other than the contact part with the guide protrusions 24 and 24 of the circumferential surface of the said hole formation plan part 2) expands in diameter in the cavity 12. As shown in FIG.

Moreover, in this invention, the moving speed of the press punch 25 and the moving speed of the guide 22 are set according to the diameter expansion design shape of the hole formation plan part 2 of the raw material 1. As shown in FIG. In addition, these movement speeds may be constant or may vary.

With the movement of the pressure punch 25 and the guide 22, the hole formation plan part 2 of the raw material 1 was guide-projection part 24 of the hole formation plan part 2, 24 (24) as mentioned above. In the state in which diameter expansion is suppressed with respect to the contact portion with), the diameter is gradually enlarged in the cavity 12 so that the material of the hole forming scheduled portion 2 is filled in the cavity 12.

7-9, when the hole formation plan part 2 of the raw material 1 expanded in diameter to a predetermined shape, the movement of the pressing punch 25 and the guide 22 is stopped. At this time, in the cavity 12, the part in which the material of the hole formation plan part 2 of the raw material 1 is not yet filled, ie, the unfilled part M, remains. In this state, the hole formation plan part 2 of the raw material 1 is enlarged in diameter substantially circular arc shape only in the width direction both sides, and is not enlarged substantially in diameter in the thickness direction.

As described above, both hole formation scheduled portions 2 and 2 of the raw material 1 are enlarged in diameter.

Subsequently, as shown in FIG. 10, the hole formation process is given to each hole formation plan part 2 which enlarged the diameter of the raw material 1 in the following procedures, respectively.

The large diameter can be achieved by operating the punch drive devices 30 and 30 without removing each hole-expansion scheduled portion 2 enlarged in diameter of the raw material 1 from the cavity 12, that is, arranged in the cavity 12. And the small diameter punches 13 and 15 are simultaneously moved out into the cavity 12. Thereby, with the two punches 13 and 15, the hole formation plan part 2 contacts the front-end | tip of both punch 13 and 15 from the mutually opposite side which sandwiched the said hole formation plan part 2 in between. Do not pressurize at the same time. In this embodiment, with both punches 13 and 15, both sides of the diameter expansion suppression direction of the hole formation plan part 2 by the both protrusion part 24 and 24 of the guide 22 (namely, a hole formation example). It presses from the thickness direction both sides of the government part 2]. Thereby, as shown in FIG. 10, the tip part 14 and 16 of both punch 13 and 15 are press-fitted into the hole formation plan part 2, and the hole formation plan part 2 is made into the cavity 12. As shown in FIG. The pressure is enlarged in the [pressure expansion process].

However, in this pressing enlargement process, as shown in FIG. 10, in the state which expanded the hole formation plan part 2 of the raw material 1, the material of the hole formation plan part 2 in the cavity 12 is carried out. The portion not yet charged, that is, the unfilled portion M is left.

Moreover, in this pressing expansion process, it is preferable to simultaneously press the hole formation plan part 2 with both punches 13 and 15. FIG. If the pressure to the hole forming scheduled portions 2 by both punches 13 and 15 is not simultaneous, the periphery of the punch 13 and 15 and the periphery of the punch insertion through holes 17 and 17 There exists a possibility that the inflow amount of material of the hole formation plan part 2 into the clearance gap 18 and 18 between surfaces may increase, and material yield may fall. However, in the present invention, the pressing on the hole forming scheduled portions 2 by the two punches 13 and 15 is not limited to being simultaneous.

Subsequently, as shown in FIG. 11, the large diameter punch 15 is moved out of the cavity 12, and the large diameter punch 15 presses the raw material 1 to the hole formation scheduled part 2 by the large diameter punch 15. Then, as shown in FIG. While releasing, the tip portion 14 of the small-diameter punch 13 is pushed deeper into the hole-forming scheduled portion 2, and the small-diameter punch 13 is passed through the hole-formed scheduled portion 2 in the thickness direction thereof (small diameter Through process of punch 13]. As a result, the small diameter through hole 3a corresponding to the diameter of the small diameter punch 13 is formed in the hole formation plan part 2. In the present invention, the small diameter punch 13 may be penetrated through the hole formation scheduled portion 2 after the pressure on the hole formation scheduled portion 2 of the raw material 1 by the large diameter punch 15 is released.

By the penetrating operation of the small diameter punch 13 to the hole formation scheduled portion 2, the excess material 2a of the hole formation scheduled portion 2 is discharged from the cavity 12 to each punch 13, 15. It flows into the clearance gap 18 and 18 between the peripheral surface of and the peripheral surface of the punch insertion hole 17,17. The surplus material 2a which flowed in turns into a burr. In addition, the introduced surplus material 2a is blocked by the webbing portions 13a and 15a of the punches 13 and 15 to prevent the discharge of the blocking die 11 to the outside. In addition, along with the penetrating operation of the small-diameter punch 13, the raw material 1 is provided in the front side portion M1 in the penetrating direction of the small-diameter punch 13 in the unfilled portion M in the cavity 12. The material of the hole formation scheduled part 2 of is filled.

Subsequently, as shown in Fig. 12, the small-diameter punch 13 is moved out of the cavity 12, and the small-diameter punch 13 in a state penetrated by the hole-forming portion 12 is formed. While extracting from 2), the distal end portion 16 of the large-diameter punch 15 is press-fitted into the small-diameter hole 3a formed in the hole-forming portion 2, and the large-diameter punch 15 is formed in the hole-forming portion 2 It penetrates into (the penetrating process of the large diameter punch 15). Thereby, the small diameter hole 3a is expanded, and the hole 3 of the desired large diameter corresponding to the diameter of the large diameter punch 15 is formed in the hole formation plan part 2 by this. In addition, in this invention, after extracting the small diameter punch 13 from the hole formation plan part 2, you may let the large diameter punch 5 penetrate the hole formation plan part 2. As shown in FIG.

By the penetrating operation of the large-diameter punch 15 to the hole-forming scheduled portion 2, the excess material 2a of the hole-formed scheduled portion 2 is released from the cavity 12 of each punch 13 and 15. It flows into the gaps 18 and 18 between the circumferential surface and the circumferential surface of the punch insertion through holes 17 and 17. The surplus material 2a which flowed in turns into a burr. In addition, the introduced surplus material 2a is blocked by the webbing portions 13a and 15a of the punches 13 and 15 to prevent the discharge of the blocking die 11 to the outside. Moreover, with the penetrating operation of this large diameter punch 15, the raw material 1 is carried out to the front side part M2 of the large diameter punch 15 in the penetrating direction in the unfilled part M in the cavity 12. The material of the hole formation scheduled part 2 of is filled. As a result, all of the unfilled portions M in the cavity 12 disappear and the material is filled in the entire cavity 12.

Subsequently, the large-diameter punch 15 is moved out of the cavity 12, and the large-diameter punch 15 in a state penetrated by the hole-forming portion 2 is extracted from the hole-forming portion 2.

Subsequently, the blocking die 11 and the fixed die 21 are disassembled and the raw material 1 is taken out from the cavity 12. Thereafter, if necessary, the burr 2a formed at the periphery of the hole 3 is removed, whereby the desired hole formation and the product (preform) 6 shown in Fig. 13 can be obtained.

And in the hole formation processing method of the said embodiment, the pair of large diameter and small diameter punch 13 of the hole formation plan part 2 of the raw material 1 arrange | positioned in the cavity 12 of the blocking die 11 is carried out. In (15), since the hole formation scheduled part 2 is pressed from the mutually opposite side, the hole formation scheduled part 2 is expanded in the state in which the unfilled part M remains in the cavity 12, Therefore, the cavity In (12), the hole formation plan part 2 can be enlarged under pressure during a fall.

In addition, since the small hole 2a is formed in the hole forming portion 2 by penetrating the small hole punch 13 through the hole forming portion 2 of the raw material 1, the hole 2a is loaded with a relatively low load. Cannot form. Moreover, the hole of the raw material 1 is formed in the front side part M1 of the small diameter punch 13 in the penetrating direction in the unfilled part M in the cavity 12 by the penetrating operation of this small diameter punch 13. The material of the formation plan part 2 is filled.

In addition, the large-diameter punch 15 is made to pass through the large-diameter punch 15 through the hole-forming scheduled portion 2 of the raw material 1 in which the small-diameter hole 2a is formed, thereby expanding the small-diameter hole 2a. Since the large diameter hole 3 is formed in (2), the hole 3 can be formed with a comparatively low load. Moreover, the hole of the raw material 1 is formed in the front side part M2 of the large diameter punch 15 in the penetration direction of the unfilled part M in the cavity 12 by the penetrating operation | movement of this large diameter punch 15. As shown in FIG. The material of the formation plan part 2 is filled. As a result, all of the unfilled portions M in the cavity 12 disappear and the material is filled in the entire cavity 12, thereby preventing the occurrence of tissue defects.

In addition, since the hole formation processing method of this embodiment does not include the process of punching out the material of the hole formation plan part 2 of the raw material 1, material yield is high.

Further, since the distal end portion 14 of the small diameter punch 13 is formed in a thin shape, the small diameter punch 13 can be penetrated through the hole formation scheduled portion 2 of the raw material 1 under a low load. In addition, the two-side tapered surface 14a is arranged so that the peripheral surface of the distal end portion 14 of the small-diameter punch 13 gradually decreases toward the distal end of the small-diameter punch 13 in the taper angle α1 (α2). 14b), the molding load can be adjusted to a predetermined value by setting the taper angles α1 and α2 of the second stage of the small-diameter punch 13. In addition, through the penetrating operation of the small-diameter punch 13, the hole-forming scheduled portion 2 of the raw material 1 can be effectively pressed and expanded to the radially outer side of the small-diameter punch 13, thereby allowing the inside of the cavity 12. The material of the hole formation scheduled part 2 of the raw material 1 can be reliably filled in the front side part M1 of the small diameter punch 13 in the penetrating direction of the unfilled part M. As shown in FIG.

In addition, since the distal end portion 16 of the large diameter punch 15 is formed in a thin tip shape, the large diameter punch 15 can be penetrated through the hole formation scheduled portion 2 of the raw material 1 under a low load. In addition, since the peripheral surface of the distal end portion 16 of the large diameter punch 15 is formed by the tapered surface 16a of one stage, the molding load is determined by setting the taper angle β1 of the tapered surface 16a. You can adjust the value. In addition, through the penetrating operation of the large-diameter punch 15, the hole-forming scheduled portion 2 of the raw material 1 can be effectively enlarged to the radially outer side of the large-diameter punch 15, thereby allowing the inside of the cavity 12 to be expanded. The material of the hole formation scheduled part 2 of the raw material 1 can be reliably filled in the front side part M2 of the large diameter punch 15 in the penetration direction of the unfilled part M. As shown in FIG. This can reliably prevent the occurrence of tissue defects.

In addition, in the state where each punch 13, 15 has penetrated into the corresponding punch insertion hole 17, 17, respectively, the circumferential surface of the punch 13, 15 and the punch insertion hole 17 are Since the clearance gap 18 and 18 which the surplus material 2a of the hole formation plan part 2 of the raw material 1 flows in in the cavity 12 are formed between the peripheral surfaces of 17, This hole forming processing method falls into the category of the forging method of the classification method. Therefore, the material of the hole formation scheduled part 2 of the raw material 1 can be filled in the unfilled part M in the cavity 12 with a comparatively low load.

Further, weir portions 13a and 15a are formed on the circumferential surface of each punch 13 and 15 to prevent the surplus material 2a flowing into the gap 18 from being discharged to the outside. 2a) can be prevented from being discharged out of the blocking die 11.

In the pressing enlargement step, the hole forming scheduled portions 2 of the raw material 1 are pressed by using both punches 13 and 15 so as not to contact the ends of the punches 13 and 15. It is possible to prevent damage or damage to the punch tips 14 and 16, which may be caused by the contact between the tips of both punches 13 and 15.

In addition, the hole formation processing method of this embodiment includes the diameter expansion process of diameter-expanding the hole formation plan part 2 of the raw material 1 before a press expansion process, In a pressure expansion process, in a diameter expansion process, Example of hole formation by guide punching portions 24 and 24 with both punches 13 and 15 in a state in which the hole forming scheduled portion 2 of the raw material 1 having an enlarged diameter is disposed in the cavity 12. It presses from both sides of the diameter expansion suppression direction of the top part (2). Therefore, when the hole formation process part 2 of the raw material 1 is enlarged in diameter beforehand, and the hole formation process is performed to the said hole formation plan part 2, such a process can be performed efficiently. .

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to what was shown to the said embodiment, A setting change is variously possible.

For example, the hole forming processing method and the hole forming processing apparatus according to the present invention are not limited to those used for producing preforms for producing vehicle arms, and are used for producing preforms for various industrial products. For example, it may be used to produce a preform for a cone rod, or may be used to produce a preform for a gear having a shaft hole.

In addition, in this invention, the hole formation plan part 2 of the raw material 1 may be located only in one place, such as an axial middle part of an raw material 1, and an axial one end part. Of course, in this invention, the shape of the raw material 1 is not limited to what is rod-shaped, The present invention can be applied to the raw material 1 of various shapes. In the present invention, the raw material 1 may be made of, for example, an extruded material, or may be made of a rolled material such as a continuous cast rolled material produced by the proper method, or may be produced by another manufacturing method. It may be.

This application is accompanied by priority claims of Japanese Patent Application No. 2005-153770, filed May 26, 2005, and US Provisional Application No. 60 / 685,870, filed June 1, 2005, the disclosure of which is incorporated herein by reference. It forms part of this application as it is.

The terms and phrases used herein are for the purpose of describing the embodiments of the present invention and are not used to limit the interpretation, and do not exclude any equivalents of the features shown and described herein. It should be appreciated that various modifications within the scope of the claims are also allowed.

INDUSTRIAL APPLICABILITY The present invention can be used for a hole forming processing method and a hole forming processing apparatus used for producing a hole forming product such as an arm for a vehicle (such as an automobile or a railroad car) or a connecting rod.

Claims (14)

The hole forming scheduled portion is pressed by pressing a hole forming scheduled portion of the material placed in the cavity of the occlusion die from a mutually opposite side with the hole forming scheduled portion being a pair of large diameter and small diameter punches which are different in diameter and arranged opposite to each other. Pressurizing and expanding the unfilled portion remaining in the cavity; A step of passing the small diameter punch through the hole formation scheduled portion of the material after releasing or releasing the pressure to the material hole formation scheduled portion by the large diameter punch; And a step of causing the large diameter punch to pass through the hole forming scheduled portion of the raw material while the small diameter punch penetrated from the hole forming scheduled portion or after being ejected from the hole forming scheduled portion of the raw material. . The tapered surface of claim 1, wherein the distal end portion of the small-diameter punch is formed in a thin tip shape, and the peripheral surface of the distal end of the small-diameter punch is gradually reduced in taper angle toward the distal end of the small-diameter punch. Hole forming processing method formed in the form. The number of steps of the tapered surface forming the peripheral surface of the tip of the small-diameter punch is set to N stages (where N? 2), The tip end portion of the large diameter punch is formed in a thin end shape, while the peripheral surface of the front end portion of the large diameter punch is formed with a single taper surface smaller than N, which is arranged so that the taper angle gradually decreases toward the tip direction of the large diameter punch. The hole forming processing method which is formed or is formed by the taper surface of 1 step | paragraph. 2. The blocking die according to claim 1, wherein each of the punching dies is provided with a punch insertion hole for communicating with the cavity. In the state where each punch is penetrated into the corresponding punch insertion hole, respectively, a gap in which excess material of the hole formation scheduled portion of the material flows in from the cavity between the peripheral surface of the punch and the peripheral surface of the punch insertion through hole. The hole forming processing method which is formed. The hole forming processing method according to claim 4, wherein a weir portion that prevents the surplus material introduced into the gap from being discharged to the outside on the peripheral surface of the punch is provided in a bulging shape in the radially outer side of the punch. 2. The hole forming method according to claim 1, wherein in the pressing enlargement step, the hole forming scheduled portion of the raw material is pressed with both punches so as not to contact the ends of the punches from opposite sides with the hole forming scheduled portion of the raw material interposed therebetween. Processing method. The material according to any one of claims 1 to 6, wherein the material has a rod shape, and a predetermined portion in the axial direction of the material is a hole forming scheduled portion, And a step of expanding the diameter of the hole forming scheduled portion of the material in advance by a swaging device before the pressing expanding step, The swaging device includes a guide having a fixed die which is continuously installed on the blocking die and fixes the material, an insertion hole for inserting and holding the hole formation scheduled portion of the material in a buckling-stopped state, and a pressing punch, A pair of diameter expansion suppression protrusions projecting in the axial direction of the guide are integrally provided at portions opposite to each other with an insertion through hole interposed between the guide portion, In the diameter-expansion step, the hole formation scheduled portion of the material fixed to the fixed die is disposed in the cavity, the hole formation scheduled portion of the material is inserted and held in the insertion through hole of the guide, and the pressure punch is subsequently moved to press the pressure. By moving the guide in the direction opposite to the movement direction of the pressing punch while pressing the hole forming scheduled portion of the raw material with the punch, the hole forming scheduled portion of the raw material exposed between the tip end portion of the guide and the fixed die is formed. The diameter is expanded in the cavity while the diameter expansion is suppressed with respect to the contact portion with the guide protrusion, In the pressing enlargement step, the hole forming processing method of pressing from both sides of the diameter-increasing suppression direction of the hole-forming scheduled portion by the guide both projections with both punches as it is while the hole-expansion scheduled portion having the diameter of the raw material is arranged in the cavity. The hole forming product obtained by the hole forming processing method in any one of Claims 1-7. Occlusion die with cavity, A pair of large-diameter and small-diameter punches, which are arranged opposite to each other on the opposite sides with the hole forming scheduled portions of the raw material in the state of being disposed in the cavity of the occlusion dies, different from each other, Pressing the hole forming scheduled portion of the material placed in the cavity of the closed die from both sides with both punches and the hole forming scheduled portion is pressed to enlarge the hole forming scheduled portion, and then to the material hole forming scheduled portion by the large diameter punch. After releasing or releasing the pressure, the small diameter punch is made to pass through the hole formation scheduled portion of the raw material, and the small diameter punch which is subsequently penetrated through the hole formation scheduled portion of the raw material is ejected or extracted from the hole formation scheduled portion, The hole forming processing apparatus which consists of making a large diameter punch penetrate the hole formation plan part of a raw material. 10. The tapered surface of claim 9, wherein the distal end portion of the small-diameter punch is formed in a thin tip shape, and the peripheral surface of the distal end portion of the small-diameter punch is gradually reduced in taper angle toward the distal end of the small-diameter punch. Hole forming processing device formed. The number of stages of the tapered surface forming the peripheral surface of the tip of the small-diameter punch is set to N stages (where N? 2), The tip end portion of the large diameter punch is formed in a thin end shape, and the peripheral surface thereof is formed with a single taper surface smaller than N, arranged so as to gradually decrease the taper angle toward the leading direction of the large diameter punch, or 1 The hole forming processing apparatus formed with the taper surface of a stage. 10. The blocking die according to claim 9, wherein each of the punching dies is provided with a punch insertion hole through which each punch penetrates and communicates with the cavity. In the state where each punch is penetrated into the corresponding punch insertion hole, respectively, a gap is formed between the periphery of the punch and the periphery of the punch insertion hole so that the surplus material of the hole formation scheduled portion of the material flows in from the cavity. Hole forming processing device. The hole forming apparatus according to claim 12, wherein a weir portion that prevents the surplus material introduced into the gap from being discharged to the outside on the peripheral surface of the punch is provided in a bulging shape in the radially outer side of the punch. The material according to any one of claims 9 to 13, wherein the material is rod-shaped, and a predetermined portion in the axial direction of the material is used as a hole forming scheduled portion, Before the pressure expansion of the hole formation scheduled portion of the raw material, a swaging device for diameter expansion of the hole formation scheduled portion of the raw material, The swaging device includes a guide having a fixed die which is continuously installed on the blocking die and fixes the material, an insertion hole for inserting and holding the hole formation scheduled portion of the material in a buckling-stopped state, and inserted into the insertion through hole of the guide. And a punch drive device for pressing the hole forming scheduled portion of the pierced material in the axial direction, and a punch driving device for moving the guide in a direction opposite to the movement direction of the pressure punch, and at the same time between the insertion through hole of the tip of the guide. A pair of diameter enlargement suppression protrusions which protrude in the axial direction of the guide are integrally provided at portions opposite to each other, When the projection part of a guide part expands the diameter with respect to the contact part with the projection part of a hole formation plan part, a part of the circumferential surface of a hole formation plan part contacts a side surface of a projection part at the time of diameter expansion of the hole formation plan part of a raw material. Device.

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