JPH0722838B2 - Stroke control device for hydraulic press machine - Google Patents

Description

The present invention relates to a stroke control device for a hydraulic press machine that performs an arbitrary press working based on a stroke operation of a cylinder device.

(Prior Art) In a hydraulic press machine, since press working is performed based on the stroke operation of the cylinder device, the hydraulic pressure of the hydraulic circuit is lowered particularly when high-speed operation is performed, and in some cases, the working cannot be performed.

In the past, this type of hydraulic pressure drop was detected by a pressure detector, and the press work was temporarily interrupted by an emergency stop.

(Problems to be Solved by the Invention) However, in a stroke control device for a hydraulic press machine in which an emergency stop is performed by a conventional pressure drop as described above, an emergency stop is immediately applied due to a pressure drop, so that the hit rate is particularly high. There was a problem that continuous processing could not be performed due to frequent emergency stops during high-speed operations such as 100-300 HPM (hit per minute).

Therefore, it is an object of the present invention to provide a stroke control device for a hydraulic press machine that can operate at high speed while avoiding an emergency stop, and that does not overload the hydraulic circuit.

[Structure of Invention]

(Means for Solving the Problem) A stroke control device of a hydraulic press machine according to the present invention for solving the above problem is based on a stroke operation in which a ram (10) is reciprocated by an operation of a cylinder device (12). NC data for inputting NC data for press working with NC tape, etc. in a stroke control device of a hydraulic press machine that performs arbitrary press working on a work (W) in cooperation with (8) and a die (9). Input section (1) and this
Based on the NC data input to the NC data input unit (1), even if the hydraulic pressure sent to the hydraulic cylinder device (12) due to the stroke operation to be performed from now on is abnormally reduced, the reduced hydraulic pressure will not be restored until the next stroke operation. A regulation value computing section (2) for computing the regulation value of the required cycle stroke time (T ₀ ) or the maximum hit rate (H ₀ ) that can return to hydraulic pressure and perform continuous stroke operation, and this regulation value computing section (2) The required cycle stroke time (T ₀ ) or maximum hit rate (H ₀ ) of the regulated value calculated in step 1 and the cycle stroke time (T) or hit rate from the punch command for instructing the start of stroke operation to the next punch command (H)
And the cycle stroke time (T) is more than the required cycle stroke time (T ₀ ) (T ≧ T ₀ ), or the hit rate (H) is less than the maximum hit rate (H ₀ ) (H And a stroke control section (3) for controlling so as to satisfy ≦ H ₀ ).

(Operation) In the stroke control device of the hydraulic press machine according to the present invention, in order to prevent the inconvenience of a decrease in hydraulic pressure due to the stroke operation, the required cycle time or hit rate of the stroke operation to be performed from now on is based on the NC data of the press working. For example, the calculation is performed as follows.

That is, the required stroke time To is such that the reciprocating stroke amount is l + α · m (α is a cylinder coefficient) and the hydraulic pump discharge amount is Q, provided that the reduced hydraulic pressure returns to the original hydraulic pressure by the next stroke operation. To = (l + α · m) / Q (1) and the maximum hit rate Ho is obtained by Ho = 1 / To (2).

Then, using the required cycle time To or the maximum hit rate Ho as a regulation value, the actual cycle time T or the hit rate H is regulated by T ≧ To ... (3) H ≦ Ho ... (4).

Therefore, in the control device for the hydraulic press machine of the present invention,
By the start of the next stroke, the hydraulic pressure can be returned to the original state, an emergency stop due to a decrease in hydraulic pressure can be prevented, and high-speed operation can be performed as much as possible.

Further, in the present invention, in addition to these controls, when an abnormal decrease in the hydraulic pressure is detected, the emergency stop is applied only when the next stroke is started and the abnormal decrease is still present.
No emergency stop is applied during the unit work, the pressure is restored at the start of the next stroke, and the hit rate can be improved as much as possible from 100 to 300 HPM.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the stroke control device of this example is an NC that inputs NC data for press working from an NC tape or the like.
The data input unit 1, the regulation value calculation unit 2, the stroke control unit 3, the hydraulic pressure decrease detection unit 4 that detects that the hydraulic pressure has decreased to a predetermined abnormal value, the restriction value calculation unit 2, and the hydraulic pressure decrease detection. An emergency stop unit 5 connected to the unit 4 is provided.

In the regulation value calculation unit, based on the NC data input to the NC data input unit 1, in response to the stroke control of the stroke control unit 3, the NC data for the corresponding stroke operation is read in advance, and the stroke is calculated in the following procedure. Alternatively, for the repeated stroke operation, the required cycle time or the maximum hit rate restriction value for preventing the hydraulic pressure from abnormally decreasing is calculated.

That is, the required stroke time To is equal to the reciprocating stroke amount of 1 + α · m (α) under the condition that even if the hydraulic pressure is abnormally lowered, the lowered hydraulic pressure returns to the original hydraulic pressure by the next stroke operation and continuous stroke operation is possible. Is the cylinder coefficient) and the discharge rate of the hydraulic pump is Q, To = (l + αm) / Q (1), and the maximum hit rate Ho is Ho = 1 / To (2).

As in the case of the normal stroke control, the stroke control unit 3 commands the stroke control amount as shown in FIG. 2, that is, the stroke amount l (lo, l ₁ ) when descending, its speed, and the start of the stroke operation. Punch commands S1, S2,
The timing output condition of S3 is calculated and output, and in this example, the processing of the regulation values To and Ho calculated by the regulation value calculation unit 2 is performed.

That is, the condition of T ≧ To or H ≦ Ho shown in the equations (3) and (4) is determined and the cycle time T is controlled to the regulation value To or more, or the hit rate H is suppressed to the regulation value Ho or less.

In the example of FIG. 2, the cycle time T ₂ for the _second stroke operation is extended by ΔT, and the control is performed by the regulation value To calculated for the stroke operation.

Although the hitlet regulation is not shown, the hit rate H is kept within the regulation value Ho, so the cycle time is inevitably long.

The emergency stop unit 5 inputs the detection signal of the oil pressure decrease detected by the oil pressure decrease detection unit 4, and refers to the fact that this signal is input and the regulation values To and Ho calculated by the regulation value calculation unit 2, Immediately before the start of the next stroke operation, apply an emergency stop only when the abnormal pressure drop still occurs.

Therefore, in this example, the emergency stop is applied only when the hydraulic pressure is abnormally lowered, and is still reduced, for example, at the end of the delay time ΔT in FIG. 2, without interrupting continuous work. And an abnormal situation can be detected.

FIG. 3 shows a flowchart of the stroke control method in which the above is summarized.

As shown in the figure, in step 301, the stroke control unit 3 calculates the stroke control amount based on the NC data, in step 302 the regulation value calculation unit 2 calculates the stroke amount, and in step 303, the stroke amount is calculated using the above-mentioned constant. The restriction value To or Ho is calculated in correspondence with Q, and the stroke control unit 3 starts stroke control in step 304.

The calculations in steps 302 and 303 are carried out in parallel with the calculations in step 301 by block look-ahead or the like before the actual stroke operation, but the stroke amount calculated in step 301 may be adopted. Absent.

In step 306, the actual cycle time T or hit rate H is compared with the regulation values To and Ho. If regulation is required, the cycle time or hit rate regulation value is set in step 307, and the stroke control of step 304 is performed. Used.

In step 305, immediately before the start point of the next stroke operation,
An abnormal pressure drop has been detected. That is, when the pressure P is less than or equal to the set value Po, an emergency stop is applied in step 308.

Steps 306 and 307 of the flowchart shown in FIG.
The processing of 1 does not necessarily need to be processed by a computer, and an interrupt signal from a 3 timer may be used.

FIG. 4 shows an example of a turret punch press as a specific example of the hydraulic press machine.

The illustrated turret punch press rotatably supports an upper turret 6 and a lower turret 7, and a pair of punches 8 and a die 9 attached to arbitrary stations of both turrets 6 and 7 are moved to a punch position by rotation of a motor M. The work W is moved, and the head of the punch 8 is pushed down by a ram (striker) 10 located above the punch 8 to punch the work W interposed between the turrets 6 and 7.

One end of the work W is gripped by the clamp device 11 and can be moved to any position on the plane coordinates.

A cylinder device 12 for raising and lowering the ram 10 is provided, and the device 12 is controlled by a hydraulic unit 13 having an electromagnetic proportional valve SOL.

FIG. 5 is an explanatory diagram showing a circuit configuration of the hydraulic unit.

As shown, the hydraulic circuit is typical and
Oil is pumped up by a hydraulic pump P and supplied to a solenoid proportional valve SOL via a check valve CV and a filter F, and the cylinder 12 is controlled at high speed by high speed operation of the solenoid proportional valve.

The pipe between the filter F and the solenoid proportional valve SOL is provided with an accumulator ACC for compensating for oil shortage and a pressure detection switch PS for detecting an abnormal decrease in pressure.

In the turret punch press with the above configuration, for example 10 mm
It is assumed that many holes will be continuously drilled at a pitch.

In this case, first, the stroke control unit 3 inputs the NC data, and in view of the fact that a lot of holes are to be drilled, as shown in FIG.
Repetition), and the movement pitch of the clamp device 11 is set. Further, at this time, the operation timings of the clamp device 11 and the ram 10 must be determined, but in this example, the punch end point is detected by the height of the ram 10 and then the moving operation of the clamp device 11 is started. Then, the next stroke operation is started immediately based on the next positioning completion signal of the clamp device 11.

On the other hand, in consideration of the fact that the processing of this example is continuous processing, the regulation value calculation unit 2 calculates the maximum value Ho of the hit rate by the equation (2).

Therefore, if the hit rate in NC data is nHPM and the regulation value is (n-Δn) HPM, the actual hit rate is larger by Δn, so an appropriate time ΔT is added as shown in FIG. , The hit rate is limited to the regulation value Ho so that an abnormal pressure drop is prevented.

Further, even if the hydraulic pressure is abnormally lowered before the start of the next stroke due to the calculation error, there is no problem because it can be detected by the pressure detector PS at this point.

Although an example of punching is shown in the above embodiment, the same applies to nibbling. The same applies to continuous drawing.

As described above, in the turret punch press of this example, continuous machining can be performed at high speed without causing an abnormal decrease in hydraulic pressure. Also, the piping of the hydraulic circuit and the accumulator AC
There is no need to expand the capacity of C more than necessary. Further, since the hydraulic circuit is not overloaded, the durability of the machine is improved.

Further, although the hydraulic turret punch press is shown in the above embodiment, the same applies to a general hydraulic press machine.

The present invention is not limited to the above-mentioned embodiments, but can be carried out in appropriate modes by making appropriate design changes.

〔The invention's effect〕

As described above, the present invention is a stroke control device for a hydraulic press machine as set forth in the claims. Therefore, it is possible to operate at high speed while avoiding an emergency stop, and there is no difficulty in the hydraulic circuit.

[Brief description of drawings]

FIG. 1 is a block diagram showing a stroke control device for a hydraulic press machine according to an embodiment of the present invention, FIG. 2 is a time chart showing its operation, FIG. 3 is a flow chart of a stroke control system, and FIG. FIG. 5 is a side view of a hydraulic press machine (turret punch press) used in the example, and FIG. 5 is an explanatory view of its hydraulic circuit. 1 …… NC data input unit 2 …… Regulatory value calculation unit 3 …… Stroke control unit 4 …… Low oil pressure detection unit 5 …… Emergency stop unit

Claims (1)

[Claims] 1. A ram (1) is provided by the operation of a cylinder device (12).
In a stroke control device of a hydraulic press machine that performs arbitrary press working on a work (W) in cooperation with a punch (8) and a die (9) based on a stroke motion that reciprocates (0), press with NC tape or the like. NC for machining
An NC data input unit (1) for inputting data, and the hydraulic cylinder device (1) associated with a stroke operation to be performed based on the NC data input to the NC data input unit (1).
Even if the hydraulic pressure sent to 2) drops abnormally, the hydraulic pressure will return to the original hydraulic pressure until the next stroke operation, and continuous stroke operation will be possible. The required cycle time (T ₀ ) or maximum hit rate (H ₀ ) A regulation value calculation unit (2) for calculating the regulation value, and a required cycle stroke time (T ₀ ) or maximum hit rate (H ₀ ) of the regulation value calculated by the regulation value calculation unit (2) and stroke operation. The cycle stroke time (T) from the punch command for instructing the start of the next punch command to the next punch command or the hit rate (H) is compared, and the cycle stroke time (T) is longer than the required cycle stroke time (T ₀ ) (T ≧ T ₀₎ to become, or Bei hit rate (H) is maximum hit rate (H ₀₎ from the following (H ≦ H ₀₎ to the controlled so that the stroke control section (3), the Hydraulic press machine stroke control device characterized by comprising Te.