JP2000301228A - Piercing method and piercing device - Google Patents

Abstract

(57) Abstract: In manufacturing a hollow extruded material (hollow product) made of an aluminum alloy, an axial forward driving force is applied to a mandrel to penetrate the mandrel through a hollow hole of a predetermined hollow billet. To provide a technique that can be advantageously used when performing piercing with a computer. In performing piercing, a position at which a stick-slip vibration is generated in a mandrel is predicted, and a forward drive speed of the mandrel is set at a speed change point set at a position until the mandrel reaches the vibration generation predicted position. While switching to low speed, at least on the forward side of the vibration occurrence predicted position, the axial retreat driving force is applied to the mandrel 24 in the axial direction.
It exerts continuously with a magnitude smaller than the forward drive force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piercing method and a piercing apparatus, and more particularly to a method for manufacturing a hollow extruded material made of an aluminum alloy, by applying an axial forward driving force to a mandrel to insert a mandrel into a hollow hole of a predetermined hollow billet. The present invention relates to a technique that can be advantageously used when performing piercing by penetrating through.

[0002]

2. Description of the Related Art Conventionally, as a method of manufacturing a hollow extruded material (hollow product) made of an aluminum alloy, a hollow billet (base tube) made of an aluminum alloy is used as a product material, and a desired shape is formed by extrusion molding. Methods for obtaining extruded materials are known. When manufacturing such a hollow extruded material, prior to extrusion, an axial forward driving force is applied to the mandrel to penetrate the mandrel into the hollow hole of the hollow billet and to penetrate the mandrel, so-called piercing. Is being done.

By the way, in such piercing, when a mandrel having an outer diameter larger than the inner diameter of the hollow hole in the hollow billet is used,
As the mandrel penetrates and penetrates into the hollow billet, stick-slip vibration occurs due to friction generated between the contact surfaces of the mandrel and the hollow billet, which has a serious effect on the piercing operation. Also, to reduce the time required for such piercing,
If the forward drive speed of the mandrel is set relatively high, severe stick-slip vibration will occur, and depending on the specifications of the billet, mandrel, etc., problems such as the mandrel being broken will be caused. If the forward drive speed of the mandrel is reduced to cope with the problem, there is an inherent problem that the piercing time becomes too long, which is not preferable from a practical point of view.

[0004]

Under such circumstances, the present inventors have conducted intensive studies and found that by applying a predetermined amount of axial retreat driving force to a mandrel that is driven forward,
It was found that even if the forward drive speed of the mandrel was made relatively high, it was possible to advantageously suppress stick-slip vibration in the mandrel, and separately, at least in the section where stick-slip vibration occurred, It has also been found that lowering the forward drive speed can effectively suppress stick-slip vibration.

[0005] Accordingly, the present invention has been completed on the basis of such knowledge, and the object of the present invention is to provide a hollow extruded material (hollow product) made of an aluminum alloy.
Another object of the present invention is to provide a piercing method that can be advantageously used in the manufacture of a piercing device. In performing piercing, it is necessary to achieve both suppression of stick-slip vibration and shortening of the piercing time. It is an object of the present invention to provide a piercing method that can be achieved in a practical manner.

Another object of the present invention is to provide a method for manufacturing a hollow extruded material by which such a piercing method can be advantageously used to produce a hollow extruded material.

Another object of the present invention is to provide a piercing apparatus that can advantageously realize the above-described piercing method.

[0008]

According to the present invention, in order to solve such a problem, an axial forward driving force is applied to a mandrel to penetrate the mandrel into a hollow hole of a hollow billet made of an aluminum alloy. The gist of the invention is a piercing method characterized in that, when piercing is performed, an axial backward driving force is applied to the mandrel with a magnitude smaller than the forward driving force.

According to the present invention, the mandrel which is driven forward by the application of an axial forward driving force is
The reverse driving force smaller than the forward driving force is
Since it is exerted in the axial direction, the stick-slip vibration can be effectively suppressed or reduced while the forward drive of the mandrel is maintained, so that breakage of the mandrel can be advantageously prevented, and furthermore, In the effective vibration suppressing action as described above, even if the forward drive speed of the mandrel is made relatively high, it can be sufficiently exerted. It is also possible to perform piercing at.

That is, in the piercing method according to the present invention as described above, the piercing method is advantageously used when manufacturing a hollow extruded material (hollow product) made of an aluminum alloy, and has excellent vibration suppression when performing piercing. The effect and the effect of shortening the piercing time can be exhibited at the same time, and as a result, the piercing efficiency and, consequently, the production efficiency in the production of the hollow extruded material can be significantly increased.

In the piercing method according to the present invention, it is advantageous to predict a position at which the stick-slip vibration is generated in the mandrel, and to cause the mandrel to move backward at least on a forward side of the vibration generation predicted position. Preferably, the force is exerted continuously.
According to the method of the present invention, at least in the section in which the occurrence of the stick-slip vibration is predicted, the reverse driving force is continuously applied to the mandrel, so that the stick-slip vibration is more efficiently and effectively performed. Can be suppressed.

Another object of the present invention is to perform piercing by applying an axial forward driving force to a mandrel and penetrating the mandrel through a hollow hole of a hollow billet made of an aluminum alloy. Predict the location of the occurrence of stick-slip vibration,
The present invention can also be solved advantageously by a piercing method characterized by switching the forward drive speed of the mandrel to a low speed at a speed change point set at a position until the mandrel reaches the vibration occurrence predicted position.

In short, in the piercing method according to the present invention, the occurrence of the stick-slip vibration is predicted and the specific operation as described above is performed based on the predicted position. In the predicted section, the forward drive speed of the mandrel is set to be low, so that the stick-slip vibration can be effectively suppressed or reduced, and as a result, the mandrel can be advantageously broken. It can be avoided. Moreover, the speed change point at which the forward drive speed of the mandrel is switched can be set at any position before the mandrel reaches the position where the stick-slip vibration is predicted to occur. By approaching the location, the piercing time can be reduced as much as possible.

Therefore, the method of the present invention is advantageously used when manufacturing a hollow extruded material made of an aluminum alloy, and when piercing is performed, suppression of stick-slip vibration and reduction of piercing time are performed. Shortening can be achieved simultaneously and effectively. Therefore, according to the method of the present invention,
The piercing efficiency and further the production efficiency of the hollow extruded material can be greatly improved.

Further, in the present invention as described above, a method of applying a reverse driving force to the mandrel in accordance with the above-described method of the present invention can be advantageously adopted, whereby the switching of the forward driving speed and the above-described method are performed. The effective effect exerted by each of the action of the reverse driving force can be exhibited synergistically, and a greater benefit can be enjoyed. In the method of the present invention, more preferably, before the mandrel reaches the speed change point, by applying the retreat driving force to the mandrel, it is possible to improve the driving stability of the mandrel, desirable.

Further, in the piercing method according to the present invention, when estimating the occurrence position of the stick-slip vibration in the mandrel, the material, the axial length and the inner diameter of the hollow hole in the hollow billet, the axial direction of the mandrel, It is preferable to make a prediction based on the length and the outer diameter dimension, so that the occurrence position of the stick-slip vibration can be predicted with higher accuracy, thereby reducing the vibration and shortening the piercing time. , Can be realized even more highly.

Still further, in the method of the present invention, the forward driving force applied to the mandrel is monitored based on a buckling limit value of the mandrel, and when the forward driving force approaches the buckling limit value, It is desirable to reduce the forward drive speed of the mandrel so that the forward drive force exerted on the mandrel does not exceed the buckling limit value. By adopting such a method, buckling of the mandrel can be advantageously avoided, so that piercing can be performed smoothly and efficiently without any interruption.

In the present invention, the mandrel is passed through the hollow hole of the hollow billet, and the hollow billet is extruded according to the piercing method according to the present invention described above. A method for producing a hollow extruded material characterized by obtaining a material is also the gist of the invention.

That is, in the method for producing a hollow extruded material according to the present invention as described above, a predetermined piercing is carried out by using the method of the present invention having various effective functions before the extrusion of the hollow billet. From where things are
The hollow extruded material can be produced efficiently and efficiently.

Further, according to the present invention, an advancing cylinder mechanism for applying an axial forward driving force to the mandrel to penetrate the mandrel through a hollow hole of a hollow billet made of aluminum alloy; A retracting cylinder mechanism for applying a retreat driving force to retreat the mandrel from the forward position, in a piercing device configured to include, by applying an axial forward driving force to the mandrel with the forward cylinder mechanism, At the same time that the mandrel is passed through the hollow hole of the hollow billet, the retreat cylinder mechanism can exert an axial retreat driving force on the mandrel with a magnitude smaller than the forward drive force of the advance cylinder mechanism. A piercing apparatus characterized in that way is also the gist of the invention.

According to such a piercing device having a structure according to the present invention, piercing can be advantageously performed in accordance with the piercing method exhibiting the characteristic effects as described above. It is possible to do well.

According to one preferred embodiment of the device of the present invention, the position at which the retraction driving force of the retraction cylinder mechanism starts acting on the mandrel can be appropriately changed and set on the forward stroke of the mandrel. It is configured as follows. By adopting such a configuration, in the above-described piercing method, it becomes possible to cause the retreat driving force to act on the mandrel at a desired position, and therefore, the above-described excellent functions can be exerted to the maximum. .

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, in order to further clarify the present invention, specific embodiments of the present invention will be described with reference to the drawings.
It will be described in detail.

First, FIG. 1 schematically shows an embodiment of a piercing device according to the present invention. In FIG. 1, the piercing device 10 includes a forward cylinder 16 and a backward cylinder 18 that are driven by a forward hydraulic pump 12 and a reverse hydraulic pump 14, respectively.
And a mandrel 24 connected to the ram 20 of the forward cylinder 16 and the piston rod 22 of the reverse cylinder 18, and a container 28 containing a hollow billet (base tube) 26 made of an aluminum alloy as a product material. The mandrel 24 is driven forward by the operation of the forward hydraulic pump 12, and the container 28
Piercing can be performed by penetrating and penetrating the hollow hole 30 of the hollow billet 26 housed in the inside, while a predetermined backward drive force is applied to the mandrel 24 by the operation of the backward hydraulic pump 14. It is possible to influence. In the piercing device 10, the operation of the forward hydraulic pump 12 and the backward hydraulic pump 14 is adjusted by the control device 32, and the mandrel 2 is moved.
4 can be controlled. Here, the forward drive and the backward drive referred to here mean that the mandrel 24 penetrates the hollow billet 26,
It is intended to drive in the penetrating direction and the pull-out direction, respectively.

More specifically, the forward cylinder 16 is constituted by a single-acting hydraulic cylinder provided with a ram 20 extending outward in the axial direction, while the cylinder chamber 34 has a forward chamber. The hydraulic pump 12 is connected, and a driving force corresponding to the discharge oil amount of the forward hydraulic pump 12 is applied to the ram 2.
0, the ram 20 can be driven to protrude. In addition, one end of a substantially solid cylindrical mandrel 24 is coaxially connected and fixed to the ram 20 at the protruding end surface thereof, and the mandrel 24 is integrally driven forward as the ram 20 protrudes. I am getting it. In short, in the piercing device 10, by driving the forward cylinder 16 in accordance with the operation of the forward hydraulic pump 12, a predetermined forward drive force is applied to the mandrel 24 in the axial direction to drive the mandrel 24 forward. , Is possible.

As the mandrel 24 used in the present invention, a mandrel whose outer diameter is larger than the inner diameter of the hollow hole 30 in the hollow billet 26 used as a product material is employed. Such a mandrel 24 may be connected to the ram 20 by being fixed to the ram 20 so that it cannot be detached.
It is more desirable to make the piercing device 10 versatile by making it detachable with respect to 0.

On the other hand, the retraction cylinder 18 is constituted by a single-acting hydraulic cylinder having a ram 36 extending to one side in the axial direction and a piston rod 22 fixed to the ram 36 and extending to the other side. The forward cylinder 16
Are arranged on both sides in the direction perpendicular to the axis. In the pair of retraction cylinders 18, 18,
One retraction hydraulic pump 14 is connected to both cylinder chambers 38, 38, and by operating the retraction hydraulic pump 14, a driving force corresponding to the discharge oil amount is applied to the rams 36, 36. By acting, each ram 36,
36 is driven to protrude, while each piston rod 22, 2
2 is driven to retract. Here, the driving forces applied to the rams 36, 36 are configured to be the same as each other. Further, each piston rod 22,22 of such a retraction cylinder 18,18.
Is fixed to a predetermined portion of the ram 20 of the forward-moving cylinder 16 via the support plate 40 so as not to be relatively displaceable, so that the backward-moving cylinder 18 , 18 can apply a predetermined retraction driving force to the mandrel 24 in the axial direction. It is to be noted that the retreat driving force can be applied to the mandrel 24 at any position on the forward stroke, not only in a state where the forward drive of the mandrel 24 is stopped, but also during the forward drive. ing.

In the retraction cylinders 18 and 18, in a state where the mandrel 24 is driven forward by the operation of the forward hydraulic pump 12, the control device 32 adjusts a control valve (not shown) and the like. The discharge of the hydraulic oil is allowed with an appropriate amount, and the positive pressure in the cylinder chambers 38, 38 can be avoided. Meanwhile,
When the operation of the forward cylinder 16 is stopped, the mandrel 24 is operated by the operation of the reverse hydraulic pump 14.
When the reverse driving force is applied to the control valve, the control device 32 adjusts a control valve (not shown) and the like to discharge the hydraulic oil, so that the positive pressure in the cylinder chamber 34 can be avoided. Thus, for example, after the end of piercing, the mandrel 24 can be easily and satisfactorily driven to retreat and return to the initial position. Further, as the hydraulic pumps 12 and 14 connected to the respective cylinders 16 and 18, those having excellent controllability of the discharge oil amount, such as variable displacement pumps, are suitably employed.

Then, in the piercing device 10,
One side in the axial direction of each of the cylinders 16 and 18 (FIG. 1)
(Middle, left), a container 28 is disposed opposite to the cylinders 16 and 18 at a predetermined interval. The container 28 has a billet accommodating hole 42 having a shape corresponding to the outer shape (here, a cylindrical shape) of the hollow billet 26 as a product material, and the hollow billet 26 is placed in the billet accommodating hole 42. It can be accommodated and fixed so that it cannot be displaced in the axial direction.
Further, the container 28 is provided with the ram 2 in the mandrel 24.
In the initial position, the end face on the opposite side to the end face 0 faces one end face in the axial direction of the container 28 (the right end face in FIG. 1), and the hollow hole 30 of the accommodated hollow billet 26 and the mandrel 24 are mutually opposed. In a state where they are aligned with
With a form that can penetrate and penetrate the mandrel 24,
Are located.

As described above, in the piercing device 10, the mandrel 24 is driven by the predetermined operation of the forward hydraulic pump 12 and / or the backward hydraulic pump 14,
Piercing is being implemented,
In the present embodiment, desired piercing can be performed according to the control of the driving state of the mandrel 24 by the control device 32.

As shown in FIG. 1, the control device 32 controls the input device 44, a speed pattern control device 46 for controlling the forward drive speed of the mandrel 24, and the reverse drive force applied to the mandrel 24. A back pressure control device 48 is provided, and based on various input values input by the input device 44 and a mandrel position actually measured by a position sensor (not shown) mounted on the mandrel 24, a predetermined control is performed. Can be performed. As the position sensor, for example, a sensor using a displacement sensor such as a potentiometer or an encoder is suitably employed.

More specifically, the speed pattern control device 46 constituting the control device 32 controls the forward drive speed of the mandrel 24 by adjusting the operation of the forward hydraulic pump 12. That is, the speed pattern control device 46 can set the target value of the forward drive speed of the mandrel 24, and outputs the forward pump tilt signal (control signal) so that the forward drive speed becomes the target value. Thus, the discharge oil amount of the forward hydraulic pump 12 can be adjusted in accordance with the control signal, and the forward cylinder 16 is driven in accordance with the discharge oil amount, whereby the mandrel 24 is moved to the desired position. It is driven at the forward drive speed. In controlling the forward drive speed of the mandrel 24,
Advantageously, feedback control is employed. The forward drive speed of the mandrel 24 can be actually measured using various known speed sensors, and more preferably, indirectly obtained using the position sensor.

In the speed pattern controller 46, in the initial stage of the forward drive of the mandrel 24, the target value of the forward drive speed is set to a predetermined high-speed reference value: h, while the mandrel 24 is driven. Specific position on forward stroke (speed change point: mandrel position indicated by A in FIG. 1)
When the target value is reached, the target value is set to the high-speed side reference value:
It is configured to switch from h to the low speed reference value: l. In short, the speed pattern control device 46 changes the forward drive speed of the mandrel 24 to a low speed at a predetermined speed change point. Therefore, the mandrel 24 moves from the speed change point to the ram speed. Until the abutment 20 comes into contact with the end face on the mandrel side (the right end face in FIG. 1) of the hollow billet 26, it is driven forward at a low speed.

The high-speed and low-speed reference values h and l used for setting the target value of the forward drive speed are the required piercing time, the dynamic characteristics of the piercing device 10, and the set position of the speed change point. In particular, in the case of the low-speed reference value: l, the forward drive speed can reduce the stick-slip vibration generated when piercing is performed. It is necessary to determine the speed so that the speed is determined, and more preferably, the speed is determined in consideration of the control by the back pressure control device 48 as described later in detail. In the present embodiment, the reference values are input by the input device 44. Furthermore, the target value of the forward drive speed is set by inputting a plurality of speed reference values on the high speed side and / or low speed side in advance for each specific factor affecting the dynamic characteristics of the speed control system. It is also possible to select an appropriate value corresponding to these factors, but here, both the high speed side and the low speed side speed reference values are input one by one. ing.

On the other hand, when the mandrel 24 is driven forward, the back pressure control device 48 causes the mandrel 24 to reach a specific position on the forward stroke (back pressure action start point: mandrel position indicated by B in FIG. 1). At this point, the output of the backward pump tilt angle signal (control signal) is started, and the output of the control signal is performed until the forward drive is completed, whereby the discharge oil corresponding to the control signal is output. Activate the retreat hydraulic pump 14 with the amount
A back pressure corresponding to the discharge oil amount can be applied to the mandrel 24. In short, under the control of the back pressure control device 48, such a backward driving force based on the back pressure is continuously applied to the mandrel 24 on the forward side of the predetermined back pressure action start point. It is. In addition, in the back pressure control device 48, the retraction hydraulic pressure is controlled so that the magnitude of the retraction driving force applied to the mandrel 24 is always smaller than the forward driving force applied to the mandrel 24. It adjusts the amount of oil discharged from the pump 14, and enables the mandrel 24 to be favorably driven forward while exerting a backward driving force. Note that the control signal output for adjusting the discharge oil amount as described above may be a control signal whose magnitude changes between outputs as long as the above-described condition regarding the magnitude of the driving force is satisfied. Good, but here, the size is constant over the entire output period.

Further, in the back pressure control device 48, when the forward drive of the mandrel 24 is stopped,
By outputting the retreat pump tilt signal (control signal) and operating the retreat hydraulic pump 14, the mandrel 24
Can be driven backward at a predetermined speed. This makes it possible to drive the mandrel 24 backward at high speed, for example, after the end of piercing, and to return to the initial position in a short time.

In the control device 32 of the present embodiment, the position at which stick-slip vibration occurs when piercing is performed is predicted, and the speed change point is determined by the speed pattern control device 46 based on the predicted vibration generation position. At the same time, the back pressure control device 48 determines the back pressure action start point.

Here, the position of the occurrence of the stick-slip vibration can be predicted by performing a simulation calculation assuming the piercing device 10, but more preferably, the piercing device 10 is used.
It is desirable to predictively obtain the values based on experiments using actual devices and past piercing results. In particular, in the present embodiment, using the piercing device 10, the material of the hollow billet, the axial length (the billet length), the inner diameter of the hollow hole (the billet hollow diameter), and the axial length of the mandrel (the mandrel length) ) And the outer diameter (mandrel diameter) are variously changed, and a piercing experiment is performed to measure the position at which the stick-slip vibration is generated. According to the (Equation 1), the predicted vibration occurrence position: Se is obtained predictively. The reference point (zero point) of the predicted vibration occurrence position: Se is determined corresponding to the reference point of the position measurement by the position sensor, and is appropriately set at any point on the forward stroke of the mandrel 24. Although it can be set, here, it is set to the initial position of the mandrel 24 to facilitate the calculation of the predicted vibration occurrence position: Se. Se = Ls−a × (b × Lm−c × Lb) (Equation 1) where Lm is a mandrel length and Lb is a billet length.
A, b, and c are setting parameters based on the results of experiments performed in advance and past piercing results.
It is determined in consideration of the billet material, billet hollow diameter and mandrel diameter. Furthermore, Ls is
The advance stroke length from the reference point, which is a parameter introduced due to setting the reference point as described above.

In short, in the control device 32 of the present embodiment, the specific influencing factors, that is, the material of the hollow billet,
The vibration occurrence position can be predicted based on the billet length (Lb) and billet hollow diameter, and the mandrel length (Lm) and mandrel diameter.
Therefore, highly accurate prediction corresponding to the specifications of the mandrel 24 and the hollow billet 26 to be used in detail can be performed.

In the above (Equation 1), the billet length: Lb, the mandrel length: Lm, and the forward stroke length: Ls are input by the input device 44. In setting the values of the setting parameters a to c, there is a method in which a data table is prepared in advance according to the billet material, the billet hollow diameter, and the value of the mandrel diameter, and the data table is used. For example, such a data table is stored in advance in a storage device (not shown), and the storage device is stored on the basis of the billet material, billet hollow diameter, and mandrel diameter input by the input device 44. It can be implemented advantageously by extracting the corresponding value from the data table, or by selecting the corresponding value from a data table externally according to these predetermined factors and inputting it from the input device 44. Here, the former method of storing a data table in advance is adopted.

The speed change pattern point and the back pressure action start point are determined in each of the speed control pattern device 46 and the back pressure control device 48 based on the predicted vibration occurrence position: Se. It will be. Here, the speed change point is set at a position until the mandrel 24 reaches the vibration generation predicted position: Se so that an effective stick-slip vibration suppression effect can be obtained. In order to advantageously reduce the time, among such set positions, the predicted vibration occurrence position: a position as close as possible to Se, that is, a position immediately before the mandrel 24 reaches the predicted vibration occurrence position: Se. Is desirable. On the other hand, the back pressure action start point is set at a position until the mandrel 24 reaches the predicted vibration occurrence position: Se so that an excellent vibration suppression function can be realized, and at least the predicted vibration generation position: Se It is preferable that the back pressure (retraction driving force) be exerted on the mandrel 24 on the forward side rather than on the forward side, but it is more preferable to set the mandrel 24 at a position until the mandrel 24 reaches the speed change point. . By such a setting, the driving stability of the mandrel 24,
As a result, the operation stability of the piercing device 10 can be advantageously ensured, and further, the setting can be made in consideration of the operation delay in the back pressure control.
This makes it possible to more reliably and stably apply a predetermined back pressure (retraction driving force) to the mandrel 24.

Incidentally, the speed change point and the back pressure action start point can be set at arbitrary positions as long as the above-mentioned setting conditions are satisfied. For example, the setting parameters in the above (Equation 1) are as follows: It can be advantageously determined by appropriately changing the values of a to c. That is, the speed change point: Sv and the back pressure action start point: Sp can be easily obtained from the calculation expressions represented by the following (Expression 2) and (Expression 3), respectively. Sv = Ls−a ′ × (b ′ × Lm−c ′ × Lb) (Expression 2) Sp = Ls−a ″ × (b ″ × Lm−c ″ × Lb) Equation 3) where a ′, b ′, c ′ and a ″, b ″, c ″ are setting parameters, and the aforementioned Sv and Sp satisfy the above-mentioned setting conditions so as to satisfy the above-mentioned setting conditions. It is determined based on the values of the setting parameters: a, b, and c in (Equation 1).

Further, in this embodiment, among the setting parameters in the above (Equation 2) and (Equation 3), b ′,
The values of c ′ and b ″ and c ″ are set to the same values as b and c in (Equation 1), and are set so that a <a ′ <a ″. According to such a setting, the speed change point: Sv,
And the back pressure action start point: Sp is not only easier to set, but also the speed change point: Sv is changed to the mandrel 2
4 is set immediately before the vibration occurrence predicted position: Se is reached, while the back pressure action start point: Sp is changed to the speed change point: Sv.
Can be set at a position until the mandrel 24 reaches the position, taking into account the operation delay in the back pressure control, thereby suppressing the stick-slip vibration and shortening the piercing time, and further stabilizing the driving of the mandrel 24. Therefore, it is possible to further improve the operability of the reverse drive force.

Each setting parameter as described above: a '
To c ′ and a ″ to c ″ are set as in the case of the setting parameters: a to c in the above (Equation 1).
A method of using a data table that is prepared in advance in accordance with the billet material, the billet hollow diameter, and the value of the mandrel diameter can be advantageously applied.Here, such a data table is stored in a storage device in advance. And a method of taking out corresponding values based on input of billet material, billet hollow diameter and mandrel diameter. Also,
As the billet length: Lb, the mandrel length: Lm, and the forward stroke length: Ls, those input by the input device 44 are used as in the case of the calculation of the predicted vibration occurrence position: Se.

The control device 32 of the present embodiment further includes a pressure control device 50 in addition to the speed pattern control device 46 and the back pressure control device 48. In the pressure control device 50, when the mandrel 24 is driven forward, the mandrel 24 starts to penetrate the hollow billet 26 from the position where the mandrel 24 starts to penetrate.
4, ie, forward drive force: F, and a load value (buckling limit value) that causes buckling in the mandrel 24:
While the calculation of FL is performed sequentially, the obtained forward driving force: F is compared with the buckling limit value: FL at any time. When the difference FL-F becomes smaller than a predetermined value, a gain: K is obtained in accordance with the following (Equation 4), and the gain is obtained by the forward pump output from the speed pattern controller 46. By multiplying by the tilt angle signal (control signal), the discharge oil amount of the forward hydraulic pump 12 is reduced, and the forward drive speed of the mandrel 24 is reduced. Note that the gain: K is 0 <K
<1 is satisfied. K = 2 × (FL-F) / F (Equation 4)

Here, the forward drive force: F is the pre-pressure applied to the mandrel 24, in other words, the pressure in the cylinder chamber 34 of the forward cylinder 16 is measured by various conventionally known pressure sensors. Then, it can be easily obtained by calculating based on the actually measured value.

On the other hand, the buckling limit value FL of the mandrel 24 is generally defined by a mandrel length, a mandrel diameter, a mandrel moving distance (mandrel position), and the like. The limit pressing force value obtained according to the mandrel buckling limit calculation formula as in 5) can be advantageously adopted as the buckling limit value: FL. FL = n × π × 2 × E × I / ((Lm−x) × 2 × α) (Expression 5), where n: terminal coefficient, E: Young's modulus, I: second moment of area, Lm : Mandrel length, x: travel distance of the mandrel, α: safety factor.

In this (Equation 5), the mandrel travel distance x is the position where the mandrel 24 is driven forward from the initial position to reach the end face of the hollow billet 26 on the mandrel side (the right end face in FIG. 1). , And is expressed as a driving distance from there to the forward side. In other words, the mandrel travel distance x is sequentially calculated based on the mandrel position detected by the position sensor from the position at which the mandrel 24 starts to penetrate the hollow billet 26. It is.

In short, in such a pressure control device 50, the buckling limit value (FL) of the mandrel 24
, The forward drive force (F) applied to the mandrel 24 is monitored, and when the forward drive force approaches the buckling limit value, the operation of the forward hydraulic pump 12 is adjusted to thereby control the mandrel 24. , The load applied to the mandrel 24 can be reduced. Therefore, the forward driving force (load) based on the pre-pressure applied to the mandrel 24 is limited to the buckling limit. It is possible to effectively avoid exceeding the value and buckling the mandrel 24.

Therefore, when piercing is performed using the piercing device 10 having such a configuration, the occurrence position of the stick-slip vibration is predicted and the predetermined position is set until the mandrel 24 reaches the vibration generation predicted position. At the speed change point, the forward drive speed of the mandrel 24 can be reduced to the extent that stick-slip vibration can be reduced. Therefore, the forward drive speed is set to such a low speed at least in the section where stick-slip vibration is predicted to occur. As a result, stick-slip vibration can be effectively reduced, breakage of the mandrel can be advantageously prevented, and the forward drive speed can be increased by moving the speed change point as close as possible to the predicted vibration occurrence position. State can be maintained for a long time, in other words, piercing time can be shortened. It is as it can be advantageously realized.

Further, according to the piercing device 10 of this embodiment, the back pressure acting on the mandrel 24 which is driven forward by the application of the axial forward driving force is determined based on the predicted position of occurrence of the stick-slip vibration. On the forward side from the starting point, a retraction driving force smaller than the forward driving force can be applied in the axial direction. Therefore, if the piercing is performed by the piercing device 10, the forward driving of the mandrel 24 is favorably maintained. In addition, the stick-slip vibration can be effectively suppressed, and breakage of the mandrel 24 can be advantageously avoided.
Such an effective vibration suppressing action can be sufficiently exerted even if the forward drive speed of the mandrel 24 is set relatively high.

Further, the piercing device 10 according to the present invention
In the above, since the control of the forward drive speed and the control of the reverse drive force can be performed simultaneously, the piercing is performed by using the piercing device 10 as described above, so that the stick-slip vibration is more effectively suppressed or reduced. In addition to the effect of shortening the piercing time by the forward drive speed control, the forward drive speed after switching at the speed change point by the action of the reverse drive force is also used for suppressing vibration in the conventional device. Since it is possible to increase the speed as compared with the speed required for the piercing, the piercing time can be further shortened.

The piercing device 10 as described above
Can be advantageously used in the production of a hollow product made of an aluminum alloy, whereby the mandrel 24 is inserted into the hollow hole 30 of the hollow billet 26 according to the present invention by the piercing device 10 as a pre-process. After the penetration, the hollow billet 26 is extruded, whereby a target hollow product (hollow extruded material) can be manufactured. in short,
The desired hollow extruded material can be obtained in a short time without breaking the mandrel 24 at all.

Incidentally, such a hollow extruded material (hollow product)
In the extrusion molding, any of conventionally known direct extrusion or indirect extrusion can be performed. In the case of performing indirect extrusion, for example, as shown in FIG. Will be performed. That is, after performing the predetermined piercing by the piercing device 10, the outer shape corresponding to the billet accommodating hole 42 of the container 28 is exhibited, and the desired hollow extruded material 5 is formed.
A die 56 having a die hole 54 for providing an outer shape 2 is used. The die 56 has a cylindrical shape extending with a predetermined length (here, it can be inserted into the billet accommodating hole 42. And the outer shape
After being attached to one end surface in the axial direction of the container 28 (having an inner hole larger than the die hole 54), with the mandrel 24 fixed in position, the die stem 58 allows the container 28 to face the opposite side of the mandrel 24 (see FIG. In FIGS. 1 and 2,
2), the hollow billet 26 is pressed through the die 56 in the direction of the arrow in FIG. 2, and the die 56 and the die stem 58 are pushed into the billet accommodating hole 42. Is extruded through the inner hole of the die stem 58, and the desired hollow extruded material 52 is obtained.

FIG. 3 shows that the piercing apparatus (10) having the above-described configuration is used to perform piercing by changing the billet length and the mandrel length in various ways, and the second term of the above (Equation 1). 2 shows the result of comparing the predicted vibration generation distance calculated according to the above with the actual vibration generation distance. Note that while the predicted value of the vibration occurrence distance is indicated by a solid line, the measured value is indicated by a white circle. As is apparent from FIG. 3, the difference between the predicted value and the actually measured value is recognized to be about 20 mm at the maximum, which is considered as a range of error from a practical point of view. The above (Equation 1) can sufficiently predict the occurrence position of the stick-slip vibration.
Be recognized.

FIGS. 4 and 5 show a piercing device according to the present embodiment (example of the present invention) and a conventionally known piercing device configured to perform piercing by simply driving the mandrel forward. (Comparative Example) was used to perform piercing, and the forward drive speed (mm / s) of the mandrel at that time, the pre-pressure and the back pressure applied to the mandrel (that is, the pressure in the cylinder chamber in each cylinder: kgf / cm ² ) are shown over time. In addition, in such a measurement, in any of them, A70 was used as a hollow billet.
An aluminum alloy having a billet length of 490 mm and a billet hollow diameter of 37 mm is used, while the mandrel has an axial length of 600 m.
m and an outer diameter of 37 mm are used.
The test was carried out in a state where the composition was heated at the temperature shown in FIG. Furthermore, in the piercing by the apparatus of the present invention, the speed change point and the back pressure action start point were determined according to the above (Equation 2) and (Equation 3), respectively. Here, the values of the setting parameters were as follows. (Equation 2): a ′ = 0.95, b ′ = 0.9, c ′ = 0.
85 (Equation 3): a ″ = 0.97, b ″ = 0.9, c ″ = 0.
85

As is clear from FIGS. 4 and 5, in the piercing by the device of the comparative example, intense stick-slip vibration occurs, and the values of the forward drive speed and the pre-pressure greatly change. In addition, it is recognized that due to such vibration, the forward drive speed of the mandrel cannot be increased, and piercing requires 135 seconds. On the other hand, in the piercing by the device of the present invention, the stick-slip vibration is suppressed or reduced as much as possible, and the time required for the piercing is only 28 seconds, which is much larger than the conventional one. It is recognized that this has been shortened.

Although the typical embodiments of the present invention have been described in detail, they are merely examples, and the present invention is not limited to any specific description according to such embodiments. Needless to say, it is not to be construed as limiting.

For example, the hollow billet used as the product material may be any of various aluminum alloys known in the art, and depending on the shape, size, etc., the hollow extruded material (product) to be manufactured may be used. Accordingly, it can be set appropriately. In addition, the specific configuration of the mandrel and container, dies and die stems used in extrusion molding, taking into account the configuration of such a hollow billet,
It can be changed as appropriate.

The forward and backward cylinder mechanisms provided in the piercing device according to the present invention can be configured in various forms according to the required performance, equipment cost, and the like. As in the embodiment, it is not always necessary to be constituted by separate single-acting hydraulic cylinders, but is constituted by a double-acting hydraulic cylinder which can have both functions of forward and backward cylinder mechanisms. But nothing is harmful.

Further, in order to apply a reverse driving force to the mandrel from a predetermined position during the forward driving of the mandrel, the hydraulic pump connected to the reverse cylinder mechanism is operated as shown in FIG. It can also be implemented by restricting the discharge of hydraulic oil by, for example, causing a control valve provided in the cylinder mechanism to perform a throttle operation.
It is possible.

Further, at the position where the backward driving force acts on the mandrel, the backward driving force may be set to act on the mandrel at least on the forward side of the predicted position where the stick-slip vibration is generated. Although it is preferable, from the stage of starting forward drive of the mandrel, the action of the backward drive force is started, and even if it is configured to be able to suppress vibration other than stick-slip vibration such as vibration induced by the drive system, There is no problem.
In addition, as a method of determining the action start position of the reverse drive force,
In advance, the vibration occurrence position is classified for each predetermined range, its representative value is determined, the representative value of the classification including the predicted vibration occurrence position is extracted, and the operation start position is obtained based on the representative value. A method can also be advantageously employed.

Furthermore, in the speed pattern control device of the illustrated piercing device, the forward drive speed is switched from high speed to low speed at the speed change point. However, the present invention is not limited to this. One or more intermediate speed stages may be provided between the high speed and the low speed, and at the speed change point, the intermediate speed may be changed to the low speed, or the stick-slip vibration may be reduced. In this case, there is no problem even if the low-speed state is set in a plurality of stages. Furthermore, in determining the speed change point, vibration occurrence positions are classified in advance for each predetermined range, a representative value is determined for each classification, and the representative value of the classification to which the predicted vibration occurrence position corresponds is determined. The speed change point may be obtained by extracting the speed change point corresponding to the representative value.

In addition, it is of course possible to introduce a predetermined lubricating oil between the contact surface between the hollow billet and the mandrel, if necessary. In addition, the prediction of the occurrence position of the stick-slip vibration and the determination of the speed change point and the action start position of the reverse driving force are performed based on such chemical properties of the lubricating oil,
In addition, it is possible to take into account the temperature change of the mandrel, etc.
When the above-mentioned (Equation 1) is adopted, the values of the set parameters: a to c are determined in consideration of the material of the illustrated hollow billet, the inner diameter of the hollow hole of the hollow billet, and the outer diameter of the mandrel. It is not always necessary to make the determination based on various factors related to piercing.

In addition, although not enumerated one by one, the present invention
Based on the knowledge of those skilled in the art, the present invention can be implemented in a form in which various changes, modifications, improvements, and the like are made.
As long as such an embodiment does not depart from the gist of the present invention, it is supposed that any of the embodiments belongs to the scope of the present invention.
Needless to say.

[0066]

As is apparent from the above description, the piercing method according to the present invention is advantageously used for producing a hollow extruded material (hollow product) made of an aluminum alloy, and is used for piercing. Exhibits the feature that both suppression of stick-slip vibration and reduction of piercing time can be achieved, and the production of a hollow extruded material according to the present invention using such a piercing method In the method, the desired hollow extruded material can be produced with high productivity and production efficiency. Further, according to the piercing device according to the present invention, such a piercing method can be advantageously implemented, and thus piercing can be performed efficiently.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram schematically showing a piercing device as one embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional explanatory view showing a specific example of a state where a hollow billet is being extruded after piercing is performed using the piercing device shown in FIG.

FIG. 3 is a graph showing a comparison between a predicted value and a measured value of a vibration generation distance in one embodiment of the present invention.

FIG. 4 is a graph showing measured values of a forward driving speed of a mandrel and a front pressure and a back pressure applied to the mandrel in one embodiment of the present invention.

FIG. 5 is a graph showing measured values of a forward drive speed of a mandrel and a pre-pressure applied to the mandrel in a comparative example of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 10 piercing device 12 forward hydraulic pump 14 backward hydraulic pump 16 forward cylinder 18 reverse cylinder 24 mandrel 26 hollow billet 28 container 30 hollow hole 32 control device 46 speed pattern control device 48 back pressure control device 50 pressure control device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Eiichi Mohri 5-11-3 Shimbashi, Minato-ku, Tokyo Sumitomo Light Metal Industries, Ltd. (72) Inventor Masato Sasaki 5-11 Shimbashi, Minato-ku, Tokyo No. 3 Sumitomo Light Metal Industries, Ltd. (72) Inventor Takayuki Fujimoto 5-11-3, Shimbashi, Minato-ku, Tokyo Sumitomo Light Metal Industries, Ltd. (72) Inventor Mine Hikita Minato-ku, Tokyo C-11-3 Sumitomo Light Metal Industry Co., Ltd. F-term (reference) 4E029 AA06 CA02

Claims (10)

[Claims] When piercing is performed by applying an axial forward driving force to a mandrel and penetrating the mandrel through a hollow hole of a hollow billet made of an aluminum alloy, the mandrel is driven backward in the axial direction with respect to the mandrel. A piercing method, wherein the force is applied with a magnitude smaller than the forward driving force. 2. The piercing method according to claim 1, wherein a position at which the stick-slip vibration is generated in the mandrel is predicted, and the backward driving force is continuously applied to the mandrel at least on a forward side of the vibration generation predicted position. . 3. When a piercing operation is performed by applying an axial forward driving force to a mandrel and penetrating the mandrel through a hollow hole of a hollow billet made of an aluminum alloy, a position at which stick-slip vibration occurs in the mandrel is predicted. A piercing method, wherein the forward drive speed of the mandrel is switched to a low speed at a speed change point set at a position until the mandrel reaches the vibration occurrence predicted position. 4. The method according to claim 1, wherein the mandrel is provided.
4. The piercing method according to claim 3, wherein the reverse driving force is exerted according to the piercing method according to claim 1. 5. The piercing method according to claim 4, wherein the reverse driving force is applied to the mandrel before the mandrel reaches the speed change point. 6. The position of occurrence of stick-slip vibration in the mandrel is predicted based on the material, the axial length and the inner diameter of the hollow hole in the hollow billet, and the axial length and the outer diameter of the mandrel. The piercing method according to claim 1. 7. A forward drive force applied to the mandrel,
By monitoring the buckling limit value of the mandrel as a reference, and when the forward drive force approaches the buckle limit value, the forward drive force applied to the mandrel is reduced by reducing the forward drive speed of the mandrel. 7. The piercing method according to claim 1, wherein the buckling limit is not exceeded. 8. A hollow extruded material is extruded by passing the mandrel through the hollow hole of the hollow billet and then extruding the hollow billet according to the piercing method according to claim 1. A method for producing a hollow extruded material, characterized by being obtained. 9. An advancing cylinder mechanism for applying an axial forward driving force to a mandrel to penetrate the mandrel into a hollow hole of a hollow billet made of an aluminum alloy, and applying an axial backward driving force to the mandrel. A retracting cylinder mechanism for retracting the mandrel from a forward position. A piercing apparatus comprising: an axial forward driving force applied to the mandrel by the forward cylinder mechanism to move the mandrel to the hollow billet. At the same time that the retraction cylinder mechanism can apply an axial retraction driving force to the mandrel with a magnitude smaller than the forward driving force of the advancing cylinder mechanism. And piercing equipment. 10. The piercing apparatus according to claim 9, wherein the position at which the reverse drive force of the reverse cylinder mechanism starts to act on the mandrel can be appropriately changed and set on the forward stroke of the mandrel.