JPS58168422A - Method and device for controlling speed of ram in metal extruding press - Google Patents

Abstract

PURPOSE:To improve operating efficiency and product yield, by controlling the supply of a pressurized liquid used for actuating a ram of a press by two valves of which openings are set stepwise and are changed continuously, and specifying the openings of the two valves at the time of rising and falling. CONSTITUTION:The opening of a PI valve 16, which is set stepwise by limit switches 30, 32, 34 used for throttling the valve 16 at full open, intermediate throttling, and highly throttling in steps respectively, is set to the intermediate step at the time of rising and falling of a press. On the other hand, the opening of a throttle valve 14 changed continuously is gradually increased or decreased in accordance with a prescribed speed pattern and a stem speed. Here in performing the speed control of a ram of a hydraulic press 2, firstly, a desired stem speed is set in a speed-pattern selecting means 40 depending on a material to be extruded. Next, pressurized water is fed to the press 2 through a valve means 18 of which opening is set previously, and the speed of a ram 4 is determined in correspondence to the opening. Then the electric voltage (ef) of a tachometer generator corresponding to the ram speed at this point of time is compared with a speed setting voltage (ei), and the 2nd valve-opening controlling mechanism 72 is driven to equalize the two voltages by repeating the comparisons.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for controlling ram speed in a metal extrusion press, and particularly to a ram speed control method and apparatus for controlling the ram speed at the beginning (rise) and end (rise) of extrusion.
The present invention relates to a ram speed control method and device that improve work efficiency and yield by controlling the extrusion speed (falling).

In conventional hot metal extrusion presses, a cast or forged material (billet) made of copper or copper alloy is heated, and then the material is extruded from a die hole by a powerful hydraulic press ram in a container to form the desired shape. The speed of the ram in this extrusion process is controlled by controlling the valve opening for a predetermined period of time after the start of extrusion, and after detecting that the predetermined speed has been reached, the speed of the ram is controlled. It was designed to switch to control. This is because even when an extrusion start command is received, the ram tends to start moving with a slight delay due to inertia. And at the end of extrusion,
It was forced to stop after switching to a low speed in response to a deceleration command.

However, if the above-mentioned ram speed control is implemented at the beginning of extrusion, in the case of copper-nickel alloy tubes, depending on the billet temperature, it may take a significant amount of time to reach a predetermined speed, resulting in a decrease in efficiency. becomes. Further, at this time, if the valve opening degree is opened too much, when the billet temperature is high, it will overshoot and cracks will appear in the extruded tube. Furthermore, there was also the disadvantage that the life of the mandrel was shortened, leading to an increase in tool costs.

In addition, when manufacturing copper and copper alloy tubes, when punching billets, extrudates from the mandrel, the so-called ``belly'', are produced, and this ``belly'' hangs from the tip of the extruded tube when it rises, and If the initial speed of extrusion is too high, the material will not fall into the drop hole cut out in the table behind the die, and will move on the table with its "belly" attached, leading to trouble and reducing work efficiency. It was.

Furthermore, if the extrusion is rapidly decelerated at the end of extrusion, such as in the case of a copper-nickel alloy, there will be undershoot because high pressure is applied for extrusion, and therefore the speed when a stop command is issued will vary. This results in the problem that the stopping position is not constant. Note that it is desirable that the speed just before stopping is as slow as possible; Since this undershoot causes the vehicle to stop, the actual limit is 15 m/s.

The present invention has been developed in view of the above circumstances, and is characterized by controlling the supply of high-pressure fluid that operates the ram in a metal extrusion press in stages to a predetermined value using a valve. A method of controlling by a valve means consisting of a first valve whose opening degree is set and a second valve whose opening degree can be continuously changed, and when the extrusion press starts up or falls down, While setting the third valve to an intermediate opening between fully open and fully closed,
The opening degree of the second valve is controlled to gradually increase or decrease according to a predetermined speed pattern and stem speed.

In order to effectively realize such a method, the present invention (a) controls the supply of high-pressure liquid that operates the ram in a metal extrusion press, and the valve opening is adjusted to a predetermined value in stages. (b) valve means consisting of a first valve to be set and a second valve whose opening degree can be continuously changed; and (b) opening of the first valve when the extrusion press starts or falls. (e) a speed corresponding to the extruded material so that the stem speed gradually increases or decreases at the start-up or fall of the extrusion press; a speed pattern selection means for selecting a pattern; (d) a stem speed detection means for detecting a stem speed; and (e) a speed pattern selected by the speed pattern selection means and detected by the stem speed detection means. and a second valve opening degree control mechanism that controls the opening degree of the second valve according to the detected value.

As a result, all of the above-mentioned problems can be solved, and according to the present invention, it is possible to smoothly increase and decelerate the rise and fall of the ram speed in a metal extrusion press. By effectively controlling the acceleration curve at the beginning of extrusion, the rise time is made uniform and work efficiency is improved, while by effectively controlling the deceleration curve at the end of extrusion, the speed at the stop is made uniform.
In addition, by keeping the speed as low as possible, it was possible to reduce variations in the thickness of the unpressed material and improve the material yield.

Moreover, when extruding metal tubes, it is possible to extend the life of the mandrel for drilling, and the "belly button" can easily fall off during drilling, and troubles caused by the "belly button" can be prevented. As a result, it has been possible to provide a ram speed control method and device that have excellent effects such as reducing the number of repair man-hours.

EMBODIMENT OF THE INVENTION Hereinafter, the ram speed control method and apparatus according to the present invention will be explained in more detail based on the embodiments shown in the drawings.

First, in Figure 1, 2 is a powerful hydraulic press,
A stem 5 is provided at the tip of the ram 4 of the hydraulic press 2, and a rack 6 is fixed to the ram 4 in its forward and backward direction. A pinion 8 meshing with the rack 6 can drive a tachogenerator IO for detecting stem speed (ram speed), and these rack 6, pinion 8, and tachogenerator 10 form a stem speed detection means 12. That's what I'm doing.

In addition, in the high-pressure water passage, the flow rate is adjusted through a throttle valve 14 (second valve) and a pressure inlet valve (PI valve) 16 (first valve).
A valve means 18 including a valve means 18 is provided, and pressurized water is supplied to the hydraulic press 2 via this valve means 18. The PI valve 16 is opened and closed by moving the rod 24 forward and backward by operating the rocker shaft 22, and moving the valve body 26 connected thereto. 8-stage limit switch that can be engaged with the kick fitting 28 provided at 24: for full opening 30. An intermediate aperture 821 and an intensity aperture 34 are provided. These eight-stage limit switches 80, 82, and 84 constitute an opening degree setting mechanism 86 for the PI pulp (first valve) 16.

These limit switches 80, 82, and 84 accurately control the amount of movement of the rod 24, so that P
This allows accurate stepwise control of the opening of the I valve 16.

In such a configuration, when controlling the ram speed according to the present invention, first, a desired stem speed is set in the speed setter 40, which is a speed pattern selection means, in accordance with the extruded material.

Next, when high pressure water is supplied to the hydraulic press 2 through the throttle valve 14 with a predetermined opening and the PI valve 16 with an intermediate throttle opening, the ram speed of the hydraulic press 2 gradually increases, and the stem speed is detected. When the voltage e of the tachogenerator 10 for the
r and the voltage e representing the stem speed of the tough generator 10
(are compared by the comparator 42, and a voltage difference ed representing the difference is output to the low-speed servo amplifier 52.The servo amplifier 52 then amplifies the voltage lea and generates a drive voltage eO corresponding to this voltage difference ed. Servo valve 6o
supply to. Then, pressure oil is sent to the cylinder 62 according to the drive voltage eo that causes the servo valve 60 to come off, and the cylinder 62 is pivotally connected to the middle part of the rod 64 to swing the rod 64 around the bottle 66. The rod 68 moving the valve body 20 increases or decreases the opening amount of the throttle valve 14. In addition, in the case of low-speed extrusion,
Low-speed servo amplifier-52 to obtain appropriate response speed
(7), but at this time the IJ relay 6 is demagnetized. In addition, in the case of high-speed extrusion, the high-speed servo amplifier 5
4 is used. At this time, the relay 56 is energized.

In this way, high pressure water is supplied to the hydraulic press 2 through the valve means 18 whose opening degree is determined, and the ram speed of the hydraulic press 2 is determined accordingly. Then, the voltage ef of the tough generator 10 corresponding to the ram speed at this point
is compared with the speed setting voltage el. By repeating such operations, the second pulp opening degree control mechanism 72 is driven so that the speed setting voltage ei becomes equal to the voltage f3f representing the actual stem speed, and the stem speed is controlled by the speed setting device 40. The speed will be adjusted to be equal to the set speed.

The speed setter 40 is used to select the speed reference pattern (acceleration/deceleration time selection) shown in Figures 2 and 5, select the low-speed servo amplifier 52 and the high-speed servo amplifier 54, and It includes a switch that controls the selection of whether or not to drop.

The speed pattern controller 41 then configures a speed reference pattern over time, which consists of a rising part where the voltage increases according to a predetermined program, a holding part where the voltage value is held constant, and a falling part where the voltage decreases. At the same time, the slopes of the rising section and the descending section are changed according to the acceleration/deceleration time selected by the speed setting device 40.

Next, taking copper alloy tube extrusion as an example, ram speed control will be explained in detail using graphs. The present embodiment corresponding to the conventional example shown in Fig. 2 (Fig. 2), Fig. 8(A), and Fig. 4(B) are respectively shown in Fig. shall be taken as a thing.

First, as a speed reference pattern, in the conventional FIG. 2(A), the extrusion start part 80 is controlled by the valve opening, and only after it is detected that the predetermined speed has been reached, the illustrated rectangular patterns 82 and 84 are started. While switching to speed control,
In FIG. 2 (B) of this example, the speed is controlled from the beginning, and there is a linear ascending section 86 at the beginning of extrusion, a holding section 88 that keeps it constant, a descending section 90 that descends linearly, and a section just before stopping. It is composed of an ultra-low speed flat section 92. Incidentally, the inclination angles θl and θ2 at the beginning and end of extrusion vary depending on the difficulty of occurrence of hunting, cracking, etc., and other processing conditions, and the inclination is not necessarily linear.

Next, regarding the opening degree of P■ pulp, unlike the conventional third pulp (in figure N, the fully open part 94 continues from the beginning and becomes the strong squeeze part 96 at the end of extrusion, the eighth pulp in this example (To) In the figure, the intermediate squeezed portion 98 continues from the beginning, and the strong squeezed portion ioo is formed just before stopping at the end of extrusion.

Therefore, the extrusion speed is lower than the conventional 4th (C in Figure N). At the beginning of extrusion, the throttle valve opening is constant, P. As a result of the pulp being fully opened, a large mountain 102 (hunting) is created at the rising edge, and it is 50 mm/8 or less. After constant speed extrusion, an undershoot 104 appears at the end of extrusion where the speed drops to near zero, and then a wavy hunting 1
06 continues, whereas in FIG. 4 (to) of this example, a slight hunting 108 is observed at the beginning of extrusion, but the ascending portion 110.06 is generally smooth. It shows a flat section 112 and a descending section 114, and becomes a constant ultra-low speed section 116 just before stopping.

Conventionally, at the beginning of extrusion (during acceleration), the PI valve was fully opened, so it could not be followed by controlling the throttle valve 14, but in this example, it could be followed by controlling the PI valve 16 to the half-open position. On the other hand, at the end of extrusion (during deceleration), conventionally the PI valve was closed too early, resulting in undershoot, but in this example, by keeping it in the half-open position until just before stopping, the second speed reference pattern
(b) Control as shown in the diagram became possible.

In addition, by setting the ram speed at the time of issuing the stop command to an extremely low speed, it was possible to reduce the variation in the unpressed thickness of the extrusion press and improve the yield. More specifically, the unpressed thickness is at least 40 mm due to the function of the press.
About n must be left, but with conventional equipment 10 to 15
There was a variation of about mm, so the remaining thickness was set to 50 mm.
It was necessary to increase the size to about 40 mm, but in this example, it has become possible to aim for a limit of 40 mm.

Next, taking pure copper pipe extrusion as another example, this example corresponding to FIGS. 5(A), 6(G), and 7(A) of the conventional example is (To) Figure 6 (B),
This is shown in Figure 7 (to).

First, the speed reference pattern is a rectangular pattern 120, 122 as described above in the conventional diagram of FIG. 5(A), but in the present example of FIG. It is a line. The reason for this is that steel pipe extrusion is easy and is extruded at a high speed of 100 to 150 mm/s, but the "belly button" definitely falls at low speeds, so the speed is kept low until the "belly button" falls off. After that, it is stepped to increase the speed.

Regarding the opening degree of the PI valve, the conventional figure 6(A) is the same as the above-mentioned figure 8(A), but the PI valve opening degree in this example is different from the above-mentioned figure 3@, and is different from the beginning of extrusion. The stepped portion 12
4. Until the end point (the point when the "belly button" falls), the intermediate constriction section 12
6, the flat part is opened fully open part 128, the intermediate drawing part 180 is opened again at the end of extrusion, and the strong drawing part 1 is opened just before stopping.
It is said to be 82.

Thus, in the extrusion speed No. 7 (middle) diagram of this example, after the "belly button" is dropped at a low speed at the beginning of extrusion, the PI valve is fully opened, the throttle valve is fully opened, high speed extrusion is started, and the flat part 184 is lowered.
Then, high-speed extrusion of 100 to 150 oa/S is continued, and at the end of extrusion, the descending section 186. Super low speed section 188
It is said that

In this way, in pure copper pipe extrusion, even though the pipe is extruded at a higher speed than in copper alloy pipe extrusion, there is no occurrence of overshoot, undershoot, large hunting, etc., and the extrusion process is carried out smoothly. .

In addition, during high-speed extrusion, it is difficult for the "belly button" to fall;
If the steel pipe is extruded with the "belly button" still attached, it may get caught on rollers, etc., causing a malfunction. On the other hand, since the malfunction occurs in the gas filling device, troublesome work such as gas discharge and replenishment is added, resulting in a large amount of work. Because of the high repair costs involved, a reliable means of removing the navel as described above is required.

As detailed above, in this embodiment, the rise time is uniform at the beginning of extrusion of the metal tube, hunting is extremely small, the operation is performed smoothly, and efficiency is improved. By reducing hunting at the end of extrusion, and by setting the stopping speed to an ultra-low speed, it is possible to reduce variations in the thickness of unpressed material and improve material yield.

Furthermore, in the extrusion of steel pipes, even when extruded at high speed, it is possible to ensure and easily remove the ``belly'', and it has excellent effects such as reducing the number of failures and repairs caused by conventional ``belly'' as much as possible. .

Although the hydraulic press 2 was used in the above-described embodiment, the present invention is not limited to this in any way, and any hydraulic press may be used, and it is applicable not only to metal pipes but also to extrusion of other metals. In addition, the speed reference pattern is also the second (B).
The present invention is not limited to the pattern shown in Fig. 5 Φ). Furthermore, the first valve opening setting mechanism 86 is also fully open 80. It is not limited to the 8-stage limit switch of 821 for intermediate aperture and 34 for strong aperture, but also 4-stage, 5-stage limit switch.
It is possible to set the opening degree of other stages such as stages.

In addition, it goes without saying that various modifications and improvements can be made to the present invention based on the knowledge of those skilled in the art without departing from the spirit thereof.

[Brief explanation of drawings]

FIG. 1 is a graph of the speed reference pattern, PI valve opening degree, and extrusion speed during unloading of an apparatus that can suitably implement the ram speed control method in a metal extrusion press according to the present invention, and FIG. , 3rd @ figure, 4th (to)
The figures are graphs corresponding to FIG. 2(A), FIG. 8(A), and FIG. 4(A), respectively, in copper alloy tube extrusion according to an embodiment of the present invention. In addition, Fig. 5(A), Fig. 6(
Figure a) and Figure 7 (A) are graphs of the speed reference pattern, PI valve opening degree, and extrusion speed in conventional pure copper tube extrusion, respectively;
The figures are graphs corresponding to FIG. 5(A), FIG. 6(A), and FIG. 7(A), respectively, in pure copper pipe extrusion according to another embodiment of the present invention. 2: Hydraulic press (extrusion press) 4: Ram 12: Stem speed detection means 14: Throttle valve (second valve) 16: PI valve (first valve) l&: Pulp means 80: Fully open limit switch 82: Intermediate Throttle limit switch 84: Strength throttle limit switch 86: PI valve opening setting mechanism (first valve opening setting mechanism) Applicant: Sumitomo Light Metal Industries, Ltd.

Claims (2)

[Claims] (1) A first valve whose pulp opening degree is set to a predetermined value in stages and a second valve whose opening degree can be continuously changed to supply high-pressure liquid that operates the ram in a metal extrusion press. In this method, when the extrusion press starts up or falls down, the first valve is set to an intermediate opening degree between fully open and fully closed; A method for controlling ram speed in a metal extrusion press, comprising controlling the opening degree of a second valve to gradually increase or decrease according to a predetermined speed pattern and stem speed. (2) A first valve that controls the supply of high-pressure fluid that operates the ram in a metal extrusion press, and the pulp opening is set to a predetermined value in stages, and the pulp opening is continuously changed. a second valve to obtain the first valve; and a second valve to obtain the
a first valve opening setting mechanism for setting the opening of the valve to a predetermined value; and a speed pattern according to the extruded material so that the stem speed gradually increases or decreases when the extrusion press starts or falls. a speed pattern selection means for selecting a stem speed; a stem speed detection means for detecting a stem speed; 1. A ram speed control device for a metal extrusion press, comprising: a second valve opening degree control mechanism that controls the opening degree of the second valve.