JP2933477B2 - Extrusion press device and extrusion press control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion press apparatus and a method for controlling an extrusion press for manufacturing an extruded aluminum material.

[0002]

2. Description of the Related Art Heretofore, in an extrusion press for manufacturing an aluminum extruded profile, a main cylinder is operated by a hydraulic device to form the extruded profile from an aluminum billet. The hydraulic circuit of this hydraulic device is provided with a mechanical relief valve, and the set pushing pressure of the main cylinder is set to a constant pressure. Also, Japanese Patent Application Laid-Open No. 5-13823
As disclosed in Japanese Unexamined Patent Publication No. 3 (2003), in order to compensate for a decrease in the extrusion pressure at the end of the aluminum billet extrusion process, an auxiliary cylinder is provided to compensate for the decrease in the extrusion pressure, and the extrusion pressure is kept constant until the end. Some of them have been proposed.

[0003]

In the former case of the above-mentioned prior art, in the early stage of extrusion of the aluminum billet, a rising time is required to rise to a constant extrusion speed. In time, the oil flow sent from the hydraulic device to the main cylinder is necessarily small. And, due to the characteristics of the relief valve, while the oil flow rate is small, the actual relief pressure is also a low value, so the hydraulic pressure applied to the main cylinder is also low,
The rise time was longer.
On the other hand, it is possible to shorten the rise time by simply increasing the oil flow rate, but in this case, the amount of oil flowing out from the relief valve also increases, and energy efficiency as a hydraulic device is poor. Disadvantage. The latter case of the prior art also compensates for a decrease in extrusion pressure at the end of the extrusion process, but at the start of extrusion, the same problem as in the former case occurs.

The present invention has been made in view of the above-mentioned problems of the prior art, and provides an extrusion press apparatus and an extrusion press control method which have a simple structure, have a short rise time during extrusion, and have good energy efficiency. The purpose is to:

[0005]

SUMMARY OF THE INVENTION The present invention has a main cylinder for driving a stem for pushing a billet, a hydraulic line for supplying hydraulic pressure to the main cylinder, and a main relief provided on the hydraulic line. An extrusion press device having a valve mounted thereon and an electromagnetic relief valve mounted on the hydraulic line in parallel with the main relief valve and set to a relatively high relief pressure in the initial stage of driving the hydraulic cylinder.

Further, the present invention has a main cylinder for driving a stem for pushing out a billet, and a hydraulic line for supplying a hydraulic pressure to the main cylinder, and a hydraulic pressure applied to the main cylinder via the hydraulic line. At the beginning of the operation of the main cylinder, the set value set by the relief valve
An extrusion press control method in which the hydraulic pressure is set to a value higher than a predetermined steady-state pressure and the set value of the hydraulic pressure is reduced to the steady-state pressure as the rising time of the pushing operation of the main cylinder elapses.

[0007]

According to the extrusion press apparatus and the extrusion press control method of the present invention, at the beginning of the operation of the main cylinder, the hydraulic pressure is set to a value higher than a predetermined steady-state pressure. Is reduced to the steady pressure so that even during the rising period when the extrusion speed is low, the oil flowing out of the relief valve is small, and the actual extrusion pressure applied to the main cylinder is maintained at a desired value without decreasing. It was made.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. The extrusion press of this embodiment is shown in FIG.
As shown in FIG. 3, a hydraulically driven main cylinder 10, a ram 12 provided in the main cylinder 10 and moved by hydraulic pressure, and a stem 14 driven together with the ram 12
And the billet 1 in the container 16 by the stem 14
7 is extruded. As shown in FIG. 1, a pair of side cylinders 18 for retreating the stem 14 are provided on both sides of the main cylinder 10.
And a hydraulic line 20 at the base end of the side cylinder 18.
a and 20b are connected. The hydraulic pipeline 20a connected to the main cylinder 10 includes a switching valve 21, a directional control valve 2,
2 and connected to a hydraulic pump 20 driven by a motor 24 via a check valve 27 of the hydraulic pipeline 20. The hydraulic line 20 b connected to the pushing operation side of the base end of the side cylinder 18 is connected to the hydraulic line 20 via the directional control valve 32.
It is connected to the. Further, the hydraulic line 20 c on the retreating operation side of the distal end portion of the side cylinder 18 is connected to the hydraulic line 20 via a direction control valve 34. These directional control valves 22, 32, 34 have switching valves 23, 33, 35, respectively.
Is attached.

Further, the directional control valve 3 is provided in the hydraulic line 20.
Main relief valve 3 which is a mechanical relief valve through 0
6, and an electromagnetic relief valve 40 is connected in parallel via an electromagnetic switching valve 38. The electromagnetic relief valve 40 is capable of continuously controlling the relief pressure.

Next, a control method of the extrusion press apparatus of this embodiment will be described. First, the pressure supplied by the hydraulic pump 26 is applied to the hydraulic line 2 via the hydraulic line 20.
It is applied to the base ends of the main cylinder 10 and the side cylinder 18 via 0a and 20b. At the same time, the switching of the switching valve 38 brings the main relief valve 36 and the electromagnetic relief valve 40 into a connected state. Main relief valve 3
The maximum hydraulic pressure applied to 6 is set to a predetermined pressure by the relief pressure of the main relief valve 36 and the ionization relief valve 40 in accordance with the shape of the profile to be extruded. Here, the set pressure of the main relief valve 36 is constant,
Initially, the set pressure of the electromagnetic relief valve 40 is set to a predetermined set pressure P ₀ higher than the set pressure P ₁ at the time of steady extrusion, as shown by the solid line in FIG. Then, in a time corresponding to the rise time T of the extrusion speed of the main cylinder 10 is lowered to a predetermined constant permanent pressure P _1. here,
Extrusion speed of the main cylinder 10, as shown in FIG. 3 (B), and is controlled to be extrusion velocity V ₀ is a predetermined set speed.

Thus, the hydraulic lines 20, 20a, 20b
Is controlled by the relief pressure set by the electromagnetic relief valve 40. And
In the rising period at the beginning of operation of the main cylinder 10, the actual relief pressure of each of the relief valves 36 and 40 is lower than the set pressure P ₀ because the extrusion speed is low and the amount of oil flowing through the hydraulic pipeline 20 is small. However, in this embodiment, as shown in FIG. 3A, the set relief pressure is set to a relatively high set pressure at the beginning of the rise of the hydraulic cylinder 10, and as the extrusion speed increases, the set pressure at the time of steady extrusion is increased. since reduced to pressure P _1, as indicated by the broken line in FIG. 3 (a), the actual extrusion pressure rises to the desired extrusion pressure quickly immediately after the start of extrusion becomes a constant value. Further, the rise time until the extrusion speed reaches a predetermined value is also shortened. Further, the electromagnetic relief valve 40
Thus, since the relief pressure at the start of rising is set high, the amount of oil flowing out from the relief valves 36 and 40 is small, and the energy efficiency is extremely high in combination with the short rising.

After the end of the extrusion, the main cylinder 10
When the valve is retracted, the switching valve 21 is switched to connect the main cylinder 10 to the oil tank side, and further, the switching valve 35 of the side cylinder 18 is switched to switch the hydraulic line 20c.
The side cylinder 18 can be driven in the backward direction by applying the hydraulic pressure from the hydraulic pump to the rear side. At the same time,
The switching valve 33 is switched to connect the hydraulic pipe line 20b on the push side of the side cylinder 18 to the oil tank side, and the main cylinder 10 is retracted.

The electromagnetic relief valve of the present invention may be one that continuously controls the relief pressure or one that changes the relief pressure in a stepwise manner. Thereafter, the extrusion pressure may be set to a lower steady-state setting pressure.

[0014]

According to the extrusion press apparatus and the extrusion press control method of the present invention, the relief pressure at the start of the main cylinder is set to a value higher than the set pressure in the steady state by the electromagnetic relief valve. Even during the slow rise time, the actual relief pressure becomes a desired value, and there is no decrease in the extrusion pressure of the main cylinder, and the rise time of the extrusion speed can be shortened. Moreover,
Since the set relief pressure is raised instead of simply increasing the oil amount, less oil flows out of the relief valve, and energy efficiency is high.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of one embodiment of an extrusion press device of the present invention.

FIG. 2 is a longitudinal sectional view of a cylinder portion of the extrusion press device of the embodiment.

FIG. 3 is a graph showing the relationship between press pressure, extrusion speed, and time of the extrusion press device of this example.

[Explanation of symbols]

 Reference Signs List 10 Main cylinder 14 Stem 20, 20a, 20c Hydraulic line 36 Main relief valve 40 Electromagnetic relief valve

Claims (3)

(57) [Claims] 1. A stem (1) for extruding a billet (17).
4) and a hydraulic pipeline (20, 2) for supplying hydraulic pressure to the main cylinder (10).
0a), a main relief valve (36) is attached to the hydraulic line (20), and the main relief valve (36) is attached to the hydraulic line (20) in parallel with the main relief valve (36). An extrusion press device comprising an electromagnetic relief valve (40) set at a relatively high relief pressure in an early stage of driving. 2. The extrusion press according to claim 1, wherein the electromagnetic relief valve (40) is provided so as to be able to continuously control the relief pressure from a relatively high value to a steady-state relief pressure. Equipment . 3. A hydraulic cylinder having a main cylinder (10) for driving a stem for pushing a billet (17) and a hydraulic pipeline (20, 20a) for supplying hydraulic pressure to the main cylinder (10). At the beginning of the operation of the main cylinder (10), the set value of the hydraulic pressure applied to the main cylinder (10) via the (20, 20a) is set to a predetermined steady pressure at the beginning of the operation of the main cylinder (10). An extruder press control method, wherein the hydraulic pressure is set to a high value, and the set value of the hydraulic pressure is reduced to the steady pressure as the rising time of the extrusion operation of the main cylinder (10) elapses.