JPH07227700A - Operation control method for hydraulic punch press - Google Patents

Abstract

PURPOSE:To make a hit ratio corresponding to a pump capacity by a simple control. CONSTITUTION:A hit ratio R is controlled by adjusting standby time TT at the elevated standby position Ha of a ram 1. In this case, a hit ratio R corresponding to a pump capacity is calculated, and the standby time TT at the standby position Ha is determined with a punch velocity V constant. The maximum hit ratio R is unequivocally decided by the pump capacity, plate thickness, punching ton, ram stroke, etc. A thin plate at a low load brings about a small ram stroke, small pressure, high hit ratio and a large oil quantity. A thick plate at a high load brings about a large ram stroke, large pressure, low hit ratio and a small oil quantity. The hydraulic system is such that the pump output (pressure X flow rate) is constant and the accumulator is of the minimum capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control method for a hydraulic punch press which performs operation control according to the capacity of a hydraulic system.

[0002]

2. Description of the Related Art When a continuous punching process is performed by a hydraulic punch press, if the hit rate is increased, the hydraulic pressure is limited even if the punching is possible due to the pump capacity limit. A heavy burden is placed on the accumulator and the like to prevent deterioration. Therefore, the pulsation becomes large and a hammer noise is generated, and this noise is added to the punching noise to increase the noise. Further, if a large load is applied to the hydraulic system as described above, the life of the device will be shortened.

As a solution to such problems,
The applicant of the present invention has proposed a method in which the punching speed is reduced when the punching tool is above the plate material (Japanese Patent Application No.
-57076). According to this, since the punching speed at the time of punching is not changed, the overload of the hydraulic system can be prevented without affecting the processing quality. However, since the speed is changed during the stroke, specific processing such as flow rate adjustment is required, which complicates the control and causes a problem of responsiveness. As a result, the hit rate may be unnecessarily reduced.

On the other hand, in a general punch press, it may be necessary to temporarily set the standby position of the ram upward so as to avoid interference between the work holder for feeding the plate material on the table and the punch tool. . In such a case, the above method of reducing the punch speed as a whole uses a plurality of punch speeds, which also complicates the control.

An object of the present invention is to provide an operation control method for a hydraulic punch press capable of achieving a hit rate suitable for pump capacity with simple control.

[0006]

The structure of the present invention will be described with reference to FIG. 1 corresponding to an embodiment. The operation control method of this hydraulic punch press is based on the rising standby position (Ha) of the ram (1).
This is a method of controlling the hit rate (R) by adjusting the waiting time (T _T ) in the. The waiting time (T _T ) at the rising waiting position is preferably set to a certain time or longer according to the pump capacity. Further, the hydraulic punch press preferably has an accumulator (10) between the hydraulic pump (9) and the ram lifting cylinder (2).

[0007]

The function is to control the hit rate (R) by adjusting the waiting time (T _T ) at the rising waiting position (Ha), that is, the control by adjusting the timer time for determining the next punch start timing. Unlike the control by adjusting the punch speed (V), processing such as flow rate adjustment is not necessary, and complicated responsiveness need not be taken into consideration, and the control is simplified. The maximum hit rate is uniquely determined according to the pump capacity, but the punch operation time (T _P ) in which the ram (1) reciprocates a predetermined stroke (L) is defined as the shortest cycle time (T _P ) which is the reciprocal of the maximum hit rate. The time subtracted from T _C is the shortest waiting time (T _T ). The punching operation time ( _TP ) is easily determined when the punching speed (V) is constant. This shortest waiting time, or this shortest waiting time plus some margin time (the shortest waiting time is effective when the positioning time of the mounting table is shorter than that)
Can be set as the actual waiting time (T _T ). In this way, with a simple control, it is possible to obtain a hit rate commensurate with the pump capacity.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. The hydraulic punch press controlled by this control method is a turret punch press in which a hydraulic cylinder 2 for driving the ram 1 up and down is installed in a press frame 3. A punch tool 4 driven up and down by a ram 1 is installed on an upper turret 5, and a die 6 corresponding to this is installed on a lower turret 7. The hydraulic cylinder 2 is a stroke position detector 1.
Have six.

The hydraulic pipe of the hydraulic cylinder 2 is connected to a hydraulic pump 9 via a control valve 8 that variably controls the stroke speed of the hydraulic cylinder 2, and an accumulator 10 is connected between the control valve 8 and the pump 9. There is. The pump 9 is driven by the motor 11. The control valve 8 is composed of a hydraulic servo valve, an electromagnetic proportional control valve, or the like. In this hydraulic system,
The output of the pump 9 is constant, that is, P (pressure) × Q (flow rate) = (constant value). The plate material feeding device 12 feeds the table 14 back and forth (Y axis direction) and left and right (X axis direction) by movement of the work holder 13 which holds the plate material end portion.

The NC device 15 is a means for executing the machining program 16 to control the entire hydraulic punch press.
It is composed of a computer type NC functional unit and a programmable controller unit. In response to the punch command output from the NC device 15, the ram hydraulic servo controller 1
A predetermined valve drive signal for driving the control valve 8 is generated by 7. The ram hydraulic servo controller 17 is a D.R.
S. It consists of C (digital servo controller).

The NC device 15 is provided with a ram stroke selecting means 18, a speed setting means 19, and a standby time calculating means 20. In addition, the ram hydraulic servo controller 17 includes a stroke setting means 21 and a speed setting means 2.
2 and a standby time timer 23 are provided. The ram stroke selecting means 18 is a means for setting the ram stroke L from the bottom dead center, that is, the rising standby position Ha, in accordance with the plate thickness. For the thin plate, the stroke L is small, and for the thick plate, the stroke L is set. Set larger. The plate thickness data is acquired from the plate thickness data description part of the machining program 24, for example. The speed setting means 19 is a means for setting the speed V for raising and lowering the ram 1, and the set speed V is taken in as the set speed of the speed setting means 22 of the ram hydraulic servo controller 17.

The standby time calculation means 20 is means for calculating the standby time T _T at the rising standby position Ha of the ram 1 from various condition data by a predetermined calculation formula described later, and the calculated standby time T _T is The standby time timer 23 in the ram hydraulic servo controller 17 is set.

Next, the control method will be described. Figure 1 (B)
Shows an example of a velocity curve of the ram 1 when punching continuously, and FIG. 2 shows a control operation of the ram hydraulic servo controller 17. Ram 1 has set speed V by punch command
When descending at a (step S1 in FIG. 2) and reaching bottom dead center H0 (S2), it starts rising at the same set speed Vb (S).
3) When it reaches the standby position (Ha), it stops. When waiting at this position, waiting time T _T has elapsed, and positioning of the mounting table is completed, the process returns to step S1 and the ram 1 is lowered again.

In the control method of this embodiment, the hit rate R in this repetitive operation is controlled by adjusting the waiting time T _T at the rising standby position Ha of the ram 1.
The hit rate R is the reciprocal of the cycle time _Tc of one punch. When the cycle time T _c is shown in seconds and the hit rate R is shown in minutes, R = 1 / T _c × 60. T _P is the time for one punch operation.

Here, there is the following relationship between each variable and constant. T _P + T _T = T _c T _P = f (V, L) T _c = f (P, Q) × η ₁ P = f (t, m, k) × η ₂ Also, (pump output) = P × Q = (constant). f
(,) Indicates that the function is determined by the number in parentheses. The meaning of each letter is V: punch speed, L: ram stroke, P: pressure, Q: flow rate, η ₁ ; efficiency, η ₂ ; efficiency,
t: plate thickness, m: processing peripheral length, k: coefficient.

From the above relational expression, it can be seen that the shortest waiting time T _T for proper operation is uniquely determined from the pump capacity when the speed V is constant. That is, _{T T = T c -T P =} f (P, Q) × η 1 -f (V, L) ...... P = f (t, m, k) × η 2 ....... (However, T _T ≧ 0)

The waiting time calculating means 20 of FIG. 1 sets a calculation formula with the above formula, and calculates the waiting time T _T according to this calculation formula. In this case, the data of the plate thickness t is obtained from the machining program 24, and the machining perimeter m is obtained by collating a tool number / machining perimeter correspondence table (not shown) from the tool command in the machining program 24. obtain. The speed V is obtained from the set value of the speed setting means 19.
The other constants η ₁ , η ₂ , and k are set in, for example, calculation formulas. Note that the waiting time T _T as calculated above, the waiting time period obtained by adding a predetermined margin time _{α (T T + α) T} T
Alternatively, the waiting time timer 23 may be set. However, T _T = constant value under a predetermined condition. ... The predetermined conditions are V ≧ Vs (set speed) and L ≧ L
When the condition of s (set stroke length) is satisfied, control is performed by the calculation of the above formula, and when the condition is not satisfied, control is performed by the above formula.

According to this operation control method, the hit time R is controlled by adjusting the waiting time T _T at the rising waiting position Ha in this way, that is, the timer time for determining the next punch start timing is adjusted. Since it is a method, unlike the control by adjusting the punch speed, processing such as flow rate adjustment is unnecessary, and it is not necessary to consider complicated responsiveness, and control is simplified. In this way, with a simple control, it is possible to obtain a hit rate commensurate with the pump capacity, plate thickness, processing circumference, punching tonnage, etc., which increases noise due to overload of the hydraulic system and hydraulic pressure. The life of the equipment can be prevented from being shortened. Also, when the plate thickness t changes, or when the standby position Ha is temporarily set high in order to avoid the interference between the work holder 13 and the punch tool 4,
The hit rate can be set to match the pump capacity.

Comparing the thin plate with the thick plate, the thin plate has a low load, a small ram stroke, a small pressure, a high hit rate, and a large amount of oil, and the thick plate has a high load and a large ram stroke. High pressure, low hit rate, and low oil volume.

[0020]

Since the operation control method for the hydraulic punch press of the present invention is a method for controlling the hit rate by adjusting the waiting time at the ascending standby position, the punch speed can be kept constant and the pump can be controlled easily. You can set a hit rate that matches your ability. As a result, it is possible to prevent an increase in noise due to overload of the hydraulic system and a reduction in the life of the hydraulic equipment by using the minimum hydraulic system. In the case of the second aspect of the invention, the standby time at the rising standby position is set to a certain time or longer according to the pump capacity, so that the above control can be performed well. Further, the above control can be better performed when the hydraulic system is provided with an accumulator.

[Brief description of drawings]

FIG. 1A is a block diagram of a control system used in an operation control method according to an embodiment of the present invention, and FIG. 1B is a graph of an example of a speed curve thereof.

FIG. 2 is a flowchart of a control operation of a servo controller used in the same embodiment.

[Explanation of symbols]

1 ... Ram, 2 ... Hydraulic cylinder, 4 ... Punch tool, 8 ... Control valve, 9 ... Pump, 10 ... Accumulator, 15 ... N
C device, 17 ... ram hydraulic servo controller, 20 ... waiting time calculating means, 23 ... waiting time timer, Ha ... waiting position, L ... ram stroke, R ... hit rate, T _C ... cycle time, T _P ... punching operation time , _T T ... the waiting time

Claims (3)

[Claims] 1. An operation control method for a hydraulic punch press, wherein a hit rate is controlled by adjusting a waiting time at a rising stand-by position of a ram. 2. The operation control method for a hydraulic punch press according to claim 1, wherein the standby time at the ram rising standby position is set to a predetermined time or longer according to the pump capacity. 3. The operation control method for a hydraulic punch press according to claim 1, wherein the hydraulic punch press is provided with an accumulator between a hydraulic pump and a ram lifting cylinder.