JP2002066684A - Backward extrusion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase depth and narrowness and improve the limit of drilling process of a stock material by linearly holding the forming part of an extrusion pin during a forming process. SOLUTION: A guide sleeve 22 linearly holding an extrusion pin 11 for a drilling process is fitted to the outer periphery of the forming part 21 of the extrusion pin 11 from the radial direction as a two-split state, and during the forming, the forming part 21 is kept straight. The guide sleeve 22 is so constituted that it is kept at a position where it covers the forming part 21 as far as the tip of the part by the urging force of a spring 26 before extruding start and it is pushed to the rear flowing part to reach it, and it returns from the retreating position after completion of extrusion. An auxiliary support ring 23 is attached to the rearwardly projected part from the guide sleeve 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold extruding method, and more particularly to a backward extruder for applying a compressive force in the axial direction to a solid blank (raw material) to produce a cup-shaped product.

[0002]

2. Description of the Related Art FIGS. 18 and 19 schematically show a part of a backward extrusion device.

[0003] Here, an extrusion pin 1 attached to a movable mold side is used.
Exemplifies a so-called punch-side rearward extruder that applies a compressive force to the blank B inserted into the stationary mold side.

The extrusion pin 1 is mounted on a pin holder 2 and is driven by a press ram (not shown) in the direction of the arrow in FIG. 18 to press the blank B in the die 3.

[0005] By this pressing force, the material is pin 1 and die 3
Flows backward, and a hole is made at the center of the blank B to obtain a bottomed cylindrical product B '.

[0006] The product B 'is usually thereafter subjected to a punching step, in which the bottom wall is punched to form a bottomless cylinder.

The extrusion pin 1 is held linearly (prevented from bending and bending) by a cylindrical guide sleeve 4 provided on the outer periphery during the molding.

In the figure, reference numeral 5 denotes a pin outer peripheral ring, and 6 denotes a die 3.
After the molding, the receiving pin 6 is pushed by a knockout pin (not shown), and the product is discharged out of the fixed mold.

[0009]

The push pin 1 is composed of a shank 7 for attaching to a mold and a forming part 8 for making a hole.

The molded portion 8 has a nose (tip).
The hole 8a is set to the same size as the hole to be machined, and a portion (main portion) 8b other than the nose secures a clearance (outer peripheral gap) c shown in FIG. 19 during molding to reduce the frictional resistance applied to the pin 1. Is set smaller than the hole size.

Here, in the conventional backward extruding device, the guide sleeve 4 is provided only in the shank portion 7 as shown in the figure, and the hepatorenal forming portion 8, which is a portion for actually performing the boring process, is in a free state. ing.

Accordingly, bending and bending of the molded portion 8 tend to occur during molding. For this reason, there are unstable elements during deep hole drilling exceeding L / D = 3 or small hole drilling with Δe = 30% or less, making it difficult to process difficult-to-press materials (SUS material, SCM material). However, there is a problem that the coaxiality and straightness of the product are deteriorated near this limit.

It is conceivable to make the guide sleeve 4 long enough to cover the molded part 8 and to be retracted as the molding proceeds. , The desired pin linear state holding action cannot be obtained. Also, the guide sleeve 4
Since it is necessary to secure a space behind the sleeve for retracting the sleeve, the portion of the molding portion 8 of the push pin 1 projecting rearward of the sleeve cannot be subjected to the holding action during molding, so There is a possibility that bending or bending occurs in the portion.

Therefore, the present invention solves such a problem,
An object of the present invention is to provide a backward extruder capable of holding a molding portion of an extrusion pin in a linear state at the time of molding to increase a processing limit.

[0015]

According to a first aspect of the present invention, there is provided a backward pushing device, wherein a pushing pin is provided on one of a movable mold and a fixed mold, and a receiving pin is provided on the other, and a solid blank is connected to the pushing pin and the receiving pin. In the rear extruder, which is formed so as to be pierced by applying a compressive force in the axial direction to the blank, a plurality of split or end rings are formed on the outer periphery of the formed portion of the extrusion pin. A guide sleeve having a shape capable of being opened in a C-shape is mounted from the same pin radial direction in a state where it can slide in the axial direction while holding the molded portion in a linear state, and this guide sleeve is mounted before starting the extrusion. Hold the forming part at the forward position to cover the leading end, and after the extrusion is completed, return to the forward position from the retracted position reached by being pushed by the rear flowing part of the blank. Provided over blanking operation means, and further provided with an auxiliary support ring for supporting a portion projecting rearwardly from the guide sleeve on the outer periphery of the ejector pin in the forming section of the extrusion pin.

According to a second aspect of the present invention, in the configuration of the first aspect, a ring holding means for holding the auxiliary support ring at a position separated rearward from the guide sleeve at the start of the extrusion is provided.

According to a third aspect of the present invention, in the configuration of the second aspect, as ring holding means, on both sides of the auxiliary support ring,
An O-ring is provided for connecting the pushing pin and the auxiliary support ring so as to be integrally movable by frictional force.

According to a fourth aspect of the present invention, in the configuration of the second aspect, a spring is provided behind the auxiliary support ring as the ring holding means.

As described above, the guide sleeve is attached to the molding portion of the extrusion pin in the form of a plurality of splits or a ring with ends and can be opened in a C-shape, and the sleeve is retracted as the molding progresses. In the middle, the molded portion can be held in a straight line by the guide sleeve. In addition, since the rear protruding portion of the push pin is supported by the auxiliary support ring, a portion of the formed portion of the push pin that protrudes rearward of the sleeve (hereinafter, referred to as a rear protruding portion) can also receive a holding action. Can be suppressed. After the molding, the guide sleeve is automatically returned from the retracted position to the advanced position before the start of molding by the sleeve operating means, so that preparation for the next molding can be automatically performed.

As described above, since the guide sleeve can suppress bending and bending of the molded portion during molding,
The limit of the depth, thinness, and type of material that can be processed can be increased. Further, by preventing bending and bending of the molded portion, coaxiality and straightness of the product can be increased.

In particular, according to the second aspect of the present invention, the auxiliary support ring supports the rear projecting portion at a position separated rearward from the guide sleeve at the start of molding, so that the intermediate portion of the rear projecting portion is formed during molding. By supporting, the deformation preventing effect can be further enhanced.

For this reason, especially when a long pin for deep hole drilling or a thin pin for fine hole drilling is used as the extrusion pin, the bending and bending of the pin can be effectively prevented, and the processing limit is further reduced. , Coaxiality and straightness can be further enhanced.

[0023]

1 to 17 show an embodiment of the present invention.
It will be explained by.

1) First Embodiment (see FIGS. 1 to 5) In the first embodiment, an example is described in which the present invention is applied to a backward extrusion device that employs a so-called punch-side working method described in the section of the prior art.

In the drawing, 11 is an extrusion pin, 12 is a pin holder to which the extrusion pin 11 is attached, 13 is a pressure receiving plate for supporting the pin holder 12 from behind, and a pressure receiving cylinder 14 is further behind the pressure receiving plate 13. The pressure cylinders 15 are provided in contact with each other in the axial direction, and a driving force of a press ram (not shown) is applied to the extrusion pin 11 via the pressure cylinder 15, the pressure receiving cylinder 14, the pressure receiving plate 13, and the pin holder 12.

16 is an outer peripheral ring, 17 is an outer peripheral ring 16
A guide plate provided at the front end opening of the housing, 18 is a housing, and 19 is an outer peripheral reinforcing ring.

The push-out pin 11 comprises a shank portion 20 and a forming portion 21 similarly to the push-out pin 1 shown in FIGS. 18 and 19, and has a main portion 21b having the same size as a hole processed by a nose 21a of the forming portion 21. Is set to a smaller dimension.

A guide sleeve 22 is provided on the outer periphery of the formed portion 21 of the push-out pin 11 so as to be able to slide in the axial direction for holding the formed portion 21 in a straight line and preventing its bending and bending.

The guide sleeve 22 has a nose 21a
And a length that can cover substantially the first half of the molded part 21 including
It is formed in a flanged cylindrical shape having an inner diameter approximately equal to that of the molded portion main portion 21b.

As shown in FIG. 5, the sleeve 22 has a pair of semi-cylindrical sleeve pieces 22a, 22a with flanges.
And is joined in a state of being fitted in the molding portion 21 from the radial direction, and is held in a cylindrical shape by the guide plate 17.

At the front end of the sleeve 22, a counterbore portion 22b into which the nose 21a of the molded portion 21 is fitted is provided.

Further, a pair of ring pieces 23a, 23a
(See FIG. 5) Split auxiliary support ring 23 made of
Are fitted from the radial direction and slidably mounted in the axial direction.

The auxiliary support ring 23 is provided on the outer peripheral ring 1.
The rear protruding portion of the molded portion 21 which is held in a ring shape by 6 and is not supported by the guide sleeve 22 is supported by the auxiliary support ring 23.

A plurality of operation pins 24 are provided between the auxiliary support ring 23 and the pressure cylinder 15.
A support block 25 for receiving the rear end and a spring 26 as a sleeve operating means for elastically supporting the support block 25 are provided, and the auxiliary support ring 23 is elastically supported by these.

On the other hand, on the fixed die side, a receiving pin 28 is provided inside the die 27 so as to be slidable in the axial direction guided by a shrink ring 29.

Behind the receiving pin 28, the pin 28
A pressure receiving cylinder 30 for supporting an axial load applied to the die is provided, and a knockout pin 31 pushed toward the die 27 by an ejector (not shown) is provided in the pressure receiving cylinder 30.
After molding, the receiving pin 28 is pushed by the knockout pin 31 and the product is discharged out of the mold. 32
Is die-based.

Next, the operation of this device will be described.

The blank B is held at the entrance of the die 27 by the chuck 33 as shown in FIG.

In this state, the movable mold as a whole moves forward and the chuck is opened, and at the same time, as shown in FIG. 2, the blank B is pushed into the die 27 and is supported by the receiving pin 28. From this state, the movable mold further advances. Then, molding is performed.

During this molding, the blank B receives a compressive force at its center, so that the peripheral wall portion flows through the gap between the extrusion pin 11 and the die 27 toward the movable mold side. Is automatically extruded out of the fixed mold as the molding proceeds, and the molding is completed as shown in FIG.

As described above, since the forming portion 21 for performing the actual drilling process on the push-out pin 11 can be held in a straight line by the guide sleeve 22 from the start to the end of the forming, the forming portion 21 at the time of forming is formed. 21 can be suppressed. In addition, since the rear protruding portion (the portion not supported by the guide sleeve 22) of the extrusion pin forming portion 21 is supported by the auxiliary support ring 23, it is possible to prevent bending and bending of this portion.

For this reason, it is possible to raise the limits of the depth, thinness, and type of the material that can be processed. For example, with regard to the hole depth that can be machined, the conventional L / D = 3 can be extended to L / D = 10 or more, and machining of Δe = 30% or less can be performed in the small hole machining.

Further, since there is no bending or bending of the molded portion 21, the coaxiality and straightness of the product can be increased.

FIG. 4 shows a state in which the entire movable mold is retracted after the molding is completed. With the retraction of the movable mold, the guide sleeve 22 covers the original first half of the molded portion 21 by the force of the spring 26. Automatically returns to the state in which

Further, after the movable mold is retracted from the state shown in FIG. 4, the receiving pin 28 is pushed toward the mold entrance by the knockout pin 31, and the product B 'is discharged out of the mold.

2) Second Embodiment (See FIGS. 6 to 9) The second embodiment shows a case where the present invention is applied to a rear extrusion device that employs a so-called die-side processing method in which an extrusion pin 11 is provided on a fixed die side. ing.

FIG. 6 shows a state at the time of starting molding, FIG. 7 shows a state at the time of completion of molding, FIG. 8 shows a state of retracting the movable mold after completion of molding, and FIG. 9 shows a state of discharging the product B 'out of the fixed mold. Each is shown.

On the fixed mold side on the right side of the figure, 34 is a guide member corresponding to the guide plate 17 of the first embodiment, 35 is a pin holder, and 36 is a guide member 34 and a pin holder 35.
, 37 are knockout pins, and 38 is a knockout pin support.

Further, reference numeral 39 denotes the knockout support 3
8, a spring as a sleeve operating means for elastically supporting the guide sleeve 22 via the knockout pin 37 and the auxiliary support ring 23; 40, an ejector pin; and 41, an ejector.

On the other hand, on the movable die side on the left side of the figure, reference numeral 42 denotes a receiving pin holder on which the receiving pin 28 is mounted, 43 denotes a pressure receiving member for supporting the receiving pin load, and 44 denotes a pressure receiving member 43.
The pressure receiving pin 45 provided behind the pressure receiving pin 44
A guide plate 46 for guiding the pressure
Is finally supported by the pressure receiving shaft 46.

Since the backward extrusion device itself using this die-side processing method is known, in this embodiment,
A detailed description of the device configuration and operation other than the main part will be omitted.

Also in this device, the structure of the main part is basically the same as that of the device of the first embodiment, and the first half of the molding portion 21 of the extrusion pin 11 provided on the fixed mold side is linearly moved by the guide sleeve 22. Is held.

The rearward projecting portion of the molded portion 21 is supported by the auxiliary support ring 23. During molding, the molded portion 21 is held in a straight line by the support action at these two locations, thereby preventing bending and bending.

Therefore, according to the second embodiment, the first
As in the embodiment, the processing limit can be increased, and the coaxiality and straightness can be improved.

3) Third Embodiment (See FIGS. 10 to 14) In both the first and second embodiments, the auxiliary support ring 23 is formed immediately after the guide sleeve 22 during molding.
In the third embodiment, the ring 23 is moved integrally with the guide sleeve 2 at the start of molding.
At a position separated from the rear of the pin 2, the center of the pin rear protruding portion is supported, and the pin approaches the guide sleeve 22 as the molding progresses (the protruding portion decreases).

Although the die-side working type backward extruder described in the second embodiment is exemplified as an application object, the following configuration can also be applied to a punch-side working type device.

The auxiliary support ring 23 is
Extrusion pin forming portion 21 at a position spaced rearward with respect to 2
And can be slid in the axial direction guided by the inner surface of the outer ring 16.

A step 16a is provided on the inner surface of the outer peripheral ring 16, and the front end position of the auxiliary support ring 23 is determined by the step 16a.
2 is maintained.

Also, on both front and rear sides of the auxiliary support ring 23, the O-rings 4
7 and 48 are fitted so as to be able to move integrally with the molding portion 21 by frictional force, and the auxiliary support ring 23 is connected to the push-out pin 11 via the O-rings 47 and 48 so as to be integrally movable therewith. .

The knockout pin 37 penetrates through the auxiliary support ring 23, and its tip directly contacts the guide sleeve 22.

In the drawing, 49 is a guide member for a guide sleeve, 50 is a reinforcing ring provided on the outer periphery of the guide member 49, 51 is a pressure receiving plate provided behind the pin holder 35, and 52 is this pressure receiving plate 51. Is a support pin provided at the rear of the vehicle.

Reference numeral 53 denotes a support pin 52 and a pressure receiving ring 5.
1. A spring as a sleeve operating means for elastically supporting the push pin 11 via the pin holder 35.

FIG. 10 shows a state in which the blank B is set at the fixed type entrance. At this time, the auxiliary support ring 23 is at the front end position, and supports substantially the center of the rear protruding portion of the pin forming portion 21 behind the guide sleeve 22.

FIG. 11 shows a state in which the blank B has been inserted into the fixed mold and has come into contact with the nose of the extrusion pin 11.

By inserting the blank, the push pin 11
And the guide sleeve 22 are simultaneously retracted, and at the same time, the auxiliary support ring 23 is also retracted integrally with the push-out pin 11.

In this state, the molding is started, and as the molding proceeds, only the guide sleeve 22 is pushed by the blank B and retreats to approach the auxiliary support ring 23, and as shown in FIG. Abut.

Thereafter, the auxiliary support ring 23 is pushed by the guide sleeve 22 and moves backward together with the sleeve 22 until the molding shown in FIG. 13 is completed.

After completion of the molding, the guide sleeve 22
Is pushed by a knockout pin 37, and the push-out pin 11 is pushed by a spring 53, respectively, and moves forward integrally.
And return to the original position.

At this time, the O-ring 4
8 moves forward together with the push-out pin 11, and FIG.
Return to the original position.

According to this configuration, the intermediate portion of the rearwardly projecting portion of the extrusion pin forming portion 21 can be supported from the start of molding to the middle of molding. For this reason, especially when a long one for deep hole processing or a thin one for fine hole processing is used as the extrusion pin 11, the bending of the pin 11,
Bending can be effectively prevented, further increasing the processing limit,
Coaxiality and straightness can be further enhanced.

4) Fourth Embodiment (See FIGS. 15 and 16) In the fourth embodiment, a modification of the third embodiment, that is,
As means for connecting the auxiliary support ring 23 so as to be able to move integrally with the push-out pin 11, a configuration using a spring 54 instead of the O-rings 47 and 48 is adopted.

The spring 54 is provided between the pressure receiving plate 13 and the auxiliary support ring 23 so as to penetrate the pin holder 35 and the pressure receiving plate 51. Reference numeral 55 denotes a spring guide attached to the auxiliary support ring 23 in a state located inside the spring 54.

FIG. 15 shows a state in which the blank B is set in the fixed mold.
At the front end position where it is pressed against the step 16a.

The auxiliary support ring 23 is moved from this state in FIG.
Until the completion of the molding shown in FIG. 6, the pin molding portion 21 is located at the intermediate portion of the rearwardly projecting portion and continues to support the same.

According to the fourth embodiment, basically the same operation and effect as those of the third embodiment can be obtained.

Incidentally, the guide sleeve 22 is not limited to being divided into two, and may be divided into three or more.
Alternatively, instead of such a split structure, as shown in FIG. 17, it is formed in an end ring shape having a cut in one place, and is opened in a C-shape as shown by an imaginary line in FIG. You may make it fit.

[0077]

As described above, according to the present invention (claim 1), the guide sleeve is attached to the extruded pin forming portion in the form of a plurality of split or end ring-shaped and openable in a C-shape. Since the sleeve is retracted with the progress of molding, the molded portion, which is the portion where drilling is actually performed, can be held in a straight line during molding. In addition, since the rear protruding portion of the formed portion of the push pin is supported by the auxiliary support ring, it is possible to prevent the rear protruding portion from being bent or bent.

As a result, it is possible to suppress the bending and bending of the molded portion during molding, thereby increasing the depth and fineness of the hole that can be processed and the type of the material, and increasing the depth and the depth that were conventionally impossible. Drilling of fineness and drilling of hard-to-press materials are possible.

Further, by preventing bending and bending of the molded portion, the coaxiality and straightness of the product can be increased.

In particular, according to the second and subsequent aspects of the present invention, the auxiliary support ring supports the rear projecting portion at a position separated rearward from the guide sleeve at the start of molding, so that the intermediate portion of the rear projecting portion is formed during molding. By supporting, the deformation preventing effect can be further enhanced.

For this reason, especially when a long pin for deep hole processing or a thin pin for fine hole processing is used as an extrusion pin, bending and bending of the pin can be effectively prevented, and the processing limit is further reduced. , Coaxiality and straightness can be further enhanced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state before a blank is inserted in a rearward extruder according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the same device in a blank inserted state.

FIG. 3 is a cross-sectional view of the same device in a molding completed state.

FIG. 4 is a cross-sectional view showing a state where a movable mold is retracted in the apparatus.

FIG. 5 is an exploded perspective view of a part of an extrusion pin, a guide sleeve, and an auxiliary support ring used in the apparatus.

FIG. 6 is a cross-sectional view showing a state before a blank is inserted in a backward pushing device according to a second embodiment of the present invention.

FIG. 7 is a sectional view of the same device in a molding completed state.

FIG. 8 is a cross-sectional view of the same device in a state where a movable mold is retracted.

FIG. 9 is a cross-sectional view showing a state where a product is discharged from the apparatus.

FIG. 10 is a cross-sectional view showing a state before inserting a blank in a backward pushing device according to a third embodiment of the present invention.

FIG. 11 is a cross-sectional view showing a state of the apparatus before starting molding.

FIG. 12 is a cross-sectional view showing a state during the molding of the apparatus.

FIG. 13 is a cross-sectional view of the same device in a molding completed state.

FIG. 14 is a cross-sectional view showing a state where a product is discharged from the apparatus.

FIG. 15 is a cross-sectional view showing a state before the start of molding of a backward extrusion device according to a fourth embodiment of the present invention.

FIG. 16 is a cross-sectional view showing a completed molding state of the apparatus.

FIG. 17 is a sectional view showing another example of the shape of the guide sleeve.

FIG. 18 is a cross-sectional view showing a blank insertion state of a conventional rear extrusion device.

FIG. 19 is a cross-sectional view showing a completed state of the apparatus.

[Explanation of symbols]

 B Blank 11 Extrusion pin 21 Extrusion pin forming part 21a Nosing of forming part 22 Guide sleeve 22a, 22a Sleeve piece 23 Auxiliary support ring 26, 39, 53 Spring (sleeve operating means) 47, 48 O-ring (ring holding means) 54 Spring 28 Receiving pin

Claims (4)

[Claims] 1. An extruding pin is provided on one of a movable type and a fixed type, and a receiving pin is provided on the other. A solid blank is sandwiched between the extruding pin and the receiving pin, and an axial compressive force is applied to the blank. In the rear extruder configured to perform drilling by adding a
Alternatively, a guide sleeve having a shape that can be opened in a C-shape with an end ring is attached from the same pin radial direction in a state where it can slide in the axial direction while holding the molded portion in a linear state, and the guide sleeve is A sleeve operating means is provided for holding the formed portion at a forward position covering the leading end before the start of extrusion, and for returning to the forward position from the retracted position reached by being pushed by the rear flowing portion of the blank after completion of the extrusion. A rear pushing device, wherein an auxiliary support ring for supporting a portion of the pin forming portion projecting rearward from the guide sleeve is provided on an outer periphery of the pushing pin. 2. The backward extruding device according to claim 1, further comprising a ring holding means for holding the auxiliary support ring at a position separated rearward from the guide sleeve at the start of the extrusion. 3. The rear extruder according to claim 2, wherein O-rings are provided on both sides of the auxiliary support ring so as to integrally move the extrusion pin and the auxiliary support ring by frictional force as ring holding means. And backward extrusion equipment. 4. The rear extruder according to claim 2, wherein a spring is provided behind the auxiliary support ring as the ring holding means.