JPS5917444Y2 - Mandrel position switching device for direct and indirect extrusion presses - Google Patents

Description

[Detailed description of the invention] This invention relates to an indirect extrusion press that extrudes tubular products without dynamic friction between the billet and the inner wall of the container. The present invention relates to providing a means for switching the position of.

When extruding a product with a small internal diameter, if the moving mandrel method is used, the diameter of the mandrel is small, so the temperature of the mandrel increases due to the heat effect from the riblet where the mandrel buckles during drilling, and the frictional force between the billet and the mandrel during extrusion. The strength of the mandrel may be reduced to such an extent that it cannot withstand

With a fixed mandrel method, only the tip of the mandrel can be made thinner and the other parts can be made larger depending on the required strength, which solves the above problem. It is necessary to prevent this from happening.

That is, if the mandrel moves forward, the inner diameter of the extruded product will no longer be constant, and there is a risk that the extrusion hole of the die will eventually be blocked.

Therefore, in indirect extrusion presses, the product is extruded through a die stem, and the outer diameter of the product is generally smaller than that in direct extrusion presses, so a fixed mandrel method is often adopted.

Let us now analyze the force applied to the mandrel in the case of the fixed mandrel method according to Figure 1.

In FIG. 1, A is a container, and a die C attached to the tip of a die stem B is fitted to the front end of the container A, and a die C attached to the tip of a pressurizing stem D is fitted to the rear end of the container A. A push plate E is fitted so that it can move forward and backward.

F is a mandrel whose front end has a small diameter portion having a diameter of Dm2 and the other portion has a diameter of Dml (larger than the inner diameter of the die), and G is a billet.

Now, apply a force Pl to the stepped part of the tip of the mandrel F.
The pressure applied to the mandrel F at a position 1 away from the tip of the presser E is KPl, the distance from the tip of the presser E to the rear end of the die C is L, and the coefficient of friction between the mandrel F and the billet G is μ.
Then, the forward force F1 that tries to move forward in the extrusion direction due to friction acting on the mandrel F is F1=μπDm1foLKP1dl, and the backward force that acts on the mandrel F in the opposite direction to the extrusion direction due to the deformation resistance of the billet. F2 becomes.

(ρ is the deformation resistance of the material, Dc is the outer diameter of the product, and Dp is the outer diameter of the product) At the initial stage of extrusion, the billet remaining in the container is long, so the frictional force applied to the mandrel is large, and F1≧
At F2, the mandrel receives a forward force, but in the fixed mandrel method, there is no problem because the mandrel is prevented from moving forward from the extrusion position.

However, when the length of the billet remaining in the container becomes shorter at the end of extrusion, the frictional force applied to the mandrel becomes smaller, and F1≦F2', that is, the mandrel may receive a backward force. In such a case, it becomes necessary to prevent the mandrel from moving not only forward but also backward.

(However, if the difference between Dml and Dm2 is small, there is no need to prevent backward movement.) Conventionally, as a means of preventing backward movement of the mandrel, the hydraulic pressure on the forward side of the mandrel was applied during extrusion. A method is adopted in which a force is generated that presses the mandrel forward by relieving it at a certain constant pressure, thereby preventing the mandrel from retreating.

That is, if the relief pressure is Pi, Pix (cross-sectional area of the pressure side of the mandrel piston)> Pi is set so that the backward force acting on the mandrel can prevent the mandrel from retreating.

However, if such measures are taken, Pix
The amount of force effective for extrusion is lost by the amount of force (cross-sectional area on the pressure side of the mandrel piston).

That is, the force of Pix (the cross-sectional area of the mandrel piston on the pressurizing side) acts in a direction that causes the main ram to retreat.

Figure 2 1 is a graph showing the relationship between the required extrusion force and the main ram stroke in the case of direct extrusion, and Figure 2 2 is a graph showing the relationship between the required extrusion force and the main ram stroke in the case of indirect extrusion. The shorter the remaining billet becomes, the greater the decrease in fo (frictional force between the billet and the container and the frictional force between the billet and the mandrel), and therefore the amount of force required for extrusion becomes smaller. Even if it is relieved, (the amount of force decreased by fo)>Pix (the cross-sectional area of the pressure side of the mandrel piston), extrusion will not become impossible due to the amount of force lost due to relief.

However, in the case of indirect extrusion, at the end of extrusion,
Even if the billet remaining in the container becomes shorter, the decrease in fo' (frictional force between the billet and the mandrel) is small, and the amount of force required for extrusion remains almost the same.In order to prevent the mandrel from retreating, it is relieved by the pressure of Pi. If this is done, the force that causes the main ram to retreat due to the relief is f.

If the amount of force reduction is greater than the amount of force reduced by ', extrusion may become impossible.

Therefore, in the case of indirect extrusion, it is extremely disadvantageous to employ such means as linofing as a means for preventing the retreat of the mandrel.

Therefore, as proposed in the technique disclosed in Japanese Patent Publication No. 52-10408, the present inventors used a fixed mandrel method. Since it is larger than the extrusion reaction force that acts to move in the opposite direction,
This prevents the mandrel from moving forward in the extrusion direction, and at the end of extrusion, the length of the billet remaining in the container becomes shorter and the frictional force becomes smaller than the extrusion reaction force, so the mandrel moves forward in the extrusion direction. Although the inventors succeeded in developing an indirect extrusion method for tubular products that prevents the product from moving backwards without reducing the extrusion force, the inventors of the present invention have conducted further intensive research.
Even if the above-mentioned point is also used as a direct extrusion press, the position of the mandrel can be easily changed.

A specific example of the mandrel side stopper type will be described in detail with reference to FIGS. 3 and 4, and a specific example of the external via sensor one-type will be described in detail with reference to FIG.

First, in FIGS. 3 and 4, 1 is a press platen, and a die stem 2 is provided at the center of the press.

Reference numeral 3 denotes a main cylinder frame, which faces the platen 1 front and back on a press bed (not shown), and both are rigidly connected by columns 4 arranged diagonally, forming a press frame with a rigid frame structure. There is.

The press platen 1 is located at the front, the main cylinder frame 3 is located at the rear, and the die stem 2 is provided on the platen 1 so as to extend rearward if the direction of press movement is the front and vice versa.

The die stem 2 has an elongated cylindrical shape, and a die hole 5 for setting the outer diameter of the product is formed at the rear end thereof.The die stem 2 is rigidly secured during extrusion by means such as a gate lock system or a tension Bordeaux hydraulic jack system (not shown) on the press platen 1. It is held in the press and can be detached from the press at will.

A container 6 is movable forward and backward in the press direction by a container moving cylinder (not shown), and a billet receiving hole 7 is formed in the center of the press.

A main ram 8 is fitted into the main cylinder 9 of the main cylinder frame 3, and a pressure stem 11 is formed on the front part of the ram 8 through a crosshead 10 above the center of the press.
A pusher plate 12 can be attached to the front end surface of 1.

13 is a side cylinder, and this piston rod 14 is connected to the crosshead 10.

15 is a mandrel piston, which is connected to the cylinder part 1 of the main ram 8.
6 and connected to the mandrel crosshead 17.

A mandrel 19 is connected to the front press center of the mandrel crosshead 17 via a mandrel holder 18.
The mandrel 19 is inserted into the pressure stem 11.

Reference numeral 20 denotes a mandrel stopper cylinder, which is formed at a diagonal position of the main cylinder frame 3, and a ram 22 is fitted into the cylinder 20, in which a receiving part 21 is formed as a blind hole from the rear end in the axial direction. A cylinder rod 23 is integrally extended to the front of the ram 22.

Reference numeral 24 denotes an engaging/disengaging body which is pivotable around a pivot shaft 25 and engages/disengages from the engaging portion 26 of the mandrel crosshead 17, and the front end large diameter portion 27 of the cylinder rod 23 comes into contact with the rear surface of the engaging/disengaging body 24. There is.

Reference numeral 28 denotes a frame (sometimes referred to as a stopper frame) on which the position switching stopper is mounted, and a plurality of tie rods 29 are fastened to the rear side of the main cylinder frame 3, and a position matching the axis of the mandrel stopper ram 22 is connected to the frame. A forwardly projecting rod 30 is provided, and the axial length of the rod 30 is at least shorter than that of the receiving portion 21 .

That is, the receiving part 21 and the rod 30 constitute a telescopic nested structure part, and the position conversion length is the length at which the position of the die hole during direct extrusion and the position of the die hole during indirect extrusion are converted in the press direction. A telescoping nested structure corresponding to the size is constructed.

Reference numeral 31 denotes a stopper for changing the position, which is rotatably provided on the tie rod 29, which is the fixed side in the figure, and is avoided from between the rod 30 and the ram 22 during indirect extrusion as shown in FIG. 22 is brought into contact.

In addition, in FIGS. 3 and 4, 32 is a shear device, which is provided in a shear frame structure 33, and a shear 34 is provided so as to be movable in a direction perpendicular to the press direction at the center of the press.
5 is the chassis cylinder.

The shear device 32 moves forward and backward in the press direction by a cylinder device 36, and in the figure, the press platen serves as a guide during this movement.

A backup arm 37 is provided on the shear frame 33 and holds the die stem 2 midway in the longitudinal direction.

In FIG. 4, 38 is a tool such as a die or die bolster for direct extrusion, which is equipped with a die hole 39 and is held by the backup arm 37 and the press platen 1, and this tool is attached to the die stem 2 outside the press or in front of the press platen 1. is exchanged with

One press cycle will be explained using the specific example shown in Fig. 3.
Figure 3 shows billet B loaded into container 6 and billet I.
・Indicates the point at which the upset and piercing are completed.

First, in order to achieve the state shown in Fig. 3, it is necessary to insert the billet l-B into the container 6, which sends pressure oil to the retracting side of the side cylinder 13 and the retracting side of the mandrel screw I/N 15. , the pressurizing stem 11 is retracted with the mandrel 19 built into the pressurizing stem 11, the container is advanced to the maximum, a billet loader is entered between the pressurizing stem 11 and the container 6, and the presser plate 12 is moved back. With the billet B placed on the extrusion center line, the container 6 is moved back.

Billet B is then inserted into container 6.

Side cylinder 13 while avoiding the billet loader.
Send pressure oil to the forward side of the crosshead 10 and mandrel crosshead 17 move forward without load, and when the pressurizing stem 11 and mandrel 19 contact the push plate 12, pressurize the main cylinder 9. ) Upset of B is done.

After that, the pressurizing stem 11 and the mandrel 19 are moved back by the amount of increase in the length of the billet B due to the drilling, and after stopping, pressure oil is applied to the forward side of the mandrel screws 1 to 15, and the mandrel crosshead Since the mandrel 17 moves forward and the mandrel 19 moves forward at the same time, the billet B is pierced here.

Note that during this piercing process, the engaging/disengaging body 24 is
5 as a fulcrum, the stopper 31 has also come off, and at the position where the tip of the mandrel 19 faces the die hole 5, pressure oil is sent to the mandrel stopper cylinder 20, and the mandrel stopper is attached to the fixed stopper frame 28. When the ram 22 comes into contact with the mandrel crosshead 17 as shown in the third figure, the large-diameter portion 27 is engaged with the mandrel crosshead 17 and the engaging/disengaging body 24 is moved.
is engaged with the engaging portion 26 by turning around the pivot 25.

This position is shown in FIG. 3. From this position shown in FIG.
When the pressure stem 11 is released and extrusion is performed by advancing the pressure stem 11, the shape of the extruded material is determined by the die hole 5 of the die stem 2 and the tip of the mandrel 19, and a hollow product is indirectly extruded.

At this time, the mandrel 19 receives a forward force due to the frictional force with the billet B, but the mandrel stopper cylinder 20
is pressurized, and since the large-diameter portion 27 of the spring rod 23 is engaged and held by the mandrel crosshead 17 by the engaging/disengaging body 24, extrusion is performed without moving forward. .

Note that during extrusion, the container 6 is moved in synchronization with the pressurizing stem 11 by a container moving cylinder (not shown), and no dynamic friction is generated between the container 6 and the billet.

At the end of extrusion, when the length of the billet remaining in the container 6 becomes shorter and the frictional force becomes smaller, the mandrel 19
tries to retreat, but the mandrel crosshead 17
The above-mentioned retreat is prevented by the engagement of the large-diameter portion 27 of the stopper rod 23 between the stopper rod 23 and the fixed side I/flange frame 28, and by the abutment of the rear end surface of the stopper ram 22.

When the extrusion is finished, the mandrel 19 is moved to the pressure stem 11
The container 6 is moved back until it coincides with the front end surface of the pressurizing stem 11, and the container 6 is moved back, in short, the push plate 12 and the discard are protruded in front of the container 6, and then the shear moving cylinder 36 is extended, the shear frame 33 is moved back together with the support arm 37, and the shear 34 is aligned with the rear end surface of the die stem 2.

After that, pressure oil is sent to the chassis cylinder 35, and the shear 34
When it enters the center of the press, the press plate 12 attached thereto is cut from the product, and the press plate 12 and the press card are ejected from the machine.

Thereafter, all members are returned to their initial positions during extrusion.

When a direct extrusion press is used as shown in FIG. 4, the position of the die hole 39 in the case of direct extrusion is moved forward from the position of the die hole 5 in the case of indirect extrusion.

That is, in place of the die stem 2 in the case of indirect extrusion, tools 38 such as die bolsters and dies are used in the case of direct extrusion.
Attach it to press platen 1.

In order to correct the displacement of the die holes 5 and 39 for direct extrusion and indirect extrusion back and forth in the press direction, a protruding rod 3 is provided on the stopper frame 28 as shown in the fourth figure.
If the stopper 31 is rotated and intervened between the front end surface of the mandrel stopper ram 22 and the rear end surface of the mandrel stopper ram 22, even in the case of direct extrusion, the mandrel 19 is prevented from moving forward during extrusion, and the mandrel 19 is stopped at the end of extrusion. 19
It is possible to prevent the rear end from moving backward.

3 and 4 are of the so-called mandrel side stopper type, but it is also possible to use a mandrel one side stopper type as shown in FIG.

In addition, in FIG. 5, the stopper type is located at the rear of the main cylinder frame 3, and the holding means for the die stem 2 is a so-called gate lock system using a gate 40. Therefore, common parts are indicated by the same reference numerals.

In FIG. 5, reference numeral 41 denotes a mandrel frame, which is located at the rear of the main cylinder frame 3 and is connected to the main cylinder frame 3 by a tie rod 42.

Reference numeral 43 designates a stopper rod, and a piston rod fitted into the piercing cylinder 16 extends rearward through the main cylinder frame 3, and is fitted into a mandrel stopper cylinder 44 formed on the mandrel stopper frame 41.

A mandrel stopper ram 45 is located at the rear of the mandrel stopper rod 43, and has a receiving portion 46 formed on its rear end surface.

A stopper frame 47 faces the mandrel l-flange frame 41 and is connected by a tie rod 48, and has a rod 49 that fits into the receiving portion 46.

That is, the receiving part 46 and the rod 49 constitute a telescopic nested structure part, and the position conversion length is a length in which the position of the die hole during direct extrusion and the position of the die hole during indirect extrusion are converted in the press direction. ) is constructed with a telescopic nested structure corresponding to the size.

Reference numeral 50 indicates a position switching stopper which is rotatably provided on the tie rod 48.

Therefore, in FIG. 5, during indirect extrusion, the stopper 50 is avoided as shown, and during extrusion, the forward force applied to the mandrel 19 is suppressed by the backward hydraulic pressure applied to the mandrel stopper cylinder 44 and the stopper frame. It is received by Mandrels I. Tubarum 45 which comes into contact with 47, and its advance is blocked.

Further, the backward force applied to the mandrel 19 is received by the forward hydraulic pressure of the stopper cylinder 44 applied to the mandrel stopper ram 45, and its retreat is prevented.

When directly extruded, the stopper frame 47
A stopper 50 is inserted between the front end surface of the rod 49 protruding from the mandrel stopper ram 45 and the rear end surface of the mandrel stopper ram 45.
The forward and backward movements of the mandrel 19 are received via this stopper 50.

This invention is as follows: Even when an indirect extrusion press is used as a direct extrusion press, there is an advantage that the movement of the mandrel can be prevented simply by the switching operation by moving in and out of the stopper.

In addition, in FIGS. 3 and 4, if the mandrel stopper cylinder 20 is formed as shown by the chain line, so-called flow pushing can be performed.

[Brief explanation of the drawing]

Fig. 1 is a principle diagram showing the force applied to the mandrel in indirect extrusion using the fixed mandrel method, Fig. 2 1゜2 shows the relationship between the required extrusion force and the main ram stroke, and Fig. 2 1 shows the force applied to the mandrel in indirect extrusion using the fixed mandrel method. Fig. 2 shows indirect extrusion, Fig. 3 is an example of the present invention and is a side sectional view of an indirect extrusion press, and Fig. 4 shows the third
The figure is a side sectional view when the press is used as a direct extrusion press, and FIG. 5 is a side sectional view showing the other side of the present invention as a tail lock type. 1...Press platen, 2...Die stem, 3...Main cylinder frame, 5...
...Die hole, 6...Container, 8...
Lord Ram, 19... Mandrel, 17...
・Mandrel crosshead (mandrel movable frame structure),
20... Mandrel stopper cylinder, 22.
...Mandrel stopperum, 23...
Mandrel stopper rod, 24... Mandrel stopper, 28... Stopper frame (fixed side press frame), 31... Switching stopper.

Claims (1)

[Scope of utility model registration request] The positions of the die stem die hole provided on the press platen for indirect extrusion and the die hole for direct extrusion are changed in the press direction, and the mandrel tip faces the respective position of each die hole, and In a mandrel position switching device for a direct extrusion/indirect extrusion press that fixes the chip in position, a main cylinder frame of a press frame consisting of the press platen and a main cylinder frame arranged opposite to the rear of the press platen or the main cylinder A mandrel stopper cylinder is attached to a mandrel stopper frame connected to the frame, and a ram fitted to the cylinder is connected to a mandrel on the press axis, and is attached to the rear of the main cylinder frame or the mandrel stopper frame. A collar frame is connected to the rear via a tie rod, and is extendable and retractable between the rear end of the ram and the stopper frame to a length corresponding to the length of the press direction position change of each die hole. A mandrel position of a direct or indirect extrusion press, characterized in that a nested structure is provided, and a stopper that can be freely engaged and fixed between the front end and the rear end of the nested structure is attached to the tie rod. Switching device.