JPH03243300A - Method and device for stroke control of press - Google Patents

Abstract

PURPOSE:To make improvement of accuracy in product size by detecting the position of the previous press stroke end, determining an error from a set value and correcting this error at the time of the next press stroke. CONSTITUTION:The error between the value of the position of the press stroke end of the previous stroke detected by a stroke detector 31 and a set value is detected and this error is outputted to a stroke adjusting mechanism 13 and is controlled in the next press stroke at the time of executing the press stroke of the specified length by a mechanical driving mechanism of a forging press device 1 and controlling the press stroke by the stroke adjusting mechanism 13. The easy control of the press stroke is executed in the state in which the pressing down force is not applied. The accuracy in size of the product are improved in this way.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a press stroke control method and device, which allows the stroke position of a press to be easily and reliably adjusted to improve the precision of one product. It is particularly suitable for forging presses.

[Prior Art] Pressing such as forging is often performed as secondary processing of metal, and press machines are often used for these processing.

For example, when forging a bar-shaped metal material, a forging press device is used, and as shown in Figs. There is a forging press device 1 equipped with an adjustment mechanism.

This forging press device 1 includes a bed 2 fixed to a foundation. A pair of columns 3, 3 are attached to the head 2 so as to be vertically movable, and the upper and lower ends are connected to a top frame 4 and a bottom frame 5, respectively, to form a movable frame 6. A lifting cylinder 7 is interposed between the bottom frame 5 and the movable frame 6 to support and raise and lower the movable frame 6.

Anvils 8 and 9 as forging tools are attached to the lower surface of the top frame 4 and the upper surface of the bed 2, respectively.

In order to apply the rolling blade through such a movable frame 6, an eccentric shaft mechanism is provided on the bed 2 as a mechanical drive mechanism 10 with a constant stroke, and the pitman arm 12 is reciprocated with a constant stroke by the eccentric shaft 11 that is rotatably driven. It has become so. The lower end of this pitman arm 12 is connected to a reduction cylinder 15 that slides within a guide portion 14 formed in the bed 2 to constitute a stroke adjustment mechanism 13. A ram 16 is mounted within the reduction cylinder 15, and a bushing rod 17 mounted within the ram 16 is mounted in contact with the bottom frame 5. Further, a lifting cylinder 18.18 is interposed between the bed 2 and the reduction cylinder 15.

A conduit 21 is connected to such a reduction cylinder 15 so as to be able to supply pressure oil in an accumulator 20 stored by a hydraulic drive source 19, and a solenoid valve 22 is provided in this conduit 21. A branch pipe 24 equipped with a large solenoid valve 23 is connected thereto. Further, pressure oil is also supplied to the lifting cylinder 7 and the pulling cylinder 18 from the accumulator 25 via solenoid valves 26 and 27, respectively.

In the forging press device 1 configured as described above, oil is sealed in the reduction cylinder 15 and the oil in the reduction cylinder 15 is pressurized with the lifting cylinder 7.7 in a contracted state, and then the eccentric shaft 11 is When rotated, the reciprocating motion of the pitman arm 12 causes the reduction cylinder 15 to
The movable frame 6 is raised and lowered via the ram 16, the bushing rod 17, and the bottom frame 5 through an internal shutter, and a forging press is performed using the upper and lower anvils 8.9.

In addition, when changing the reduction amount of the forging press, the solenoid valves 22 and 23 are used to supply pressure oil into the reduction cylinder 15, and conversely to discharge pressure oil from the ram 1.
This can be done by adjusting the protrusion amount of 6.

Furthermore, when changing the spacing between the upper and lower anvils 8 and 9 due to changes in the material to be forged, etc., the length of the rod is adjusted by supplying and discharging pressure oil to the lifting cylinder 7.7 using the solenoid valve 26. This is done by doing this.

In the case of such a forging press, the main forming tool is formed by rotating the eccentric shaft due to the compressibility of the hydraulic oil in the reduction cylinder 15 and the conduit, the deformation of each part constituting the movable frame 6, etc. The movement will be different from the theoretical reciprocating action line (sine curve).

This movement will change as the pressing force changes,
In order to maintain the stroke end position of the main forming tool at a target value in response to this change, the following method has been used.

Here, the stroke end position refers to the point where the distance between the anvils 8 and 9 is the minimum due to the reciprocating movement of the anvils 8 and 9 obtained by the rotation of the eccentric shaft.

■ A method to prevent further press stroke by sandwiching a block gauge between the upper and lower anvils 8 and 9.

■ Detects the amount of movement of the anvil 8, 9, etc., and based on this detection result, supplies and discharges pressure oil to the reduction cylinder 15 using a servo valve, etc. so that the operation of the anvil 8 always follows the theoretical operating line. Method.

■ A method of changing the stroke adjustment mechanism 13 from a hydraulic type to a mechanical type and making the rigidity extremely high to prevent errors from occurring.

■ How the operator operates the press in anticipation of errors.

1. Problems to be Solved by the Invention] However, all of these methods (1) to (3) have the following problems.

In the case of ■, a gauge block must be prepared for each product dimension order, which incurs manufacturing costs, and a gauge block must be selected and installed each time.
There is a problem in that productivity decreases due to replacement.

Furthermore, since the rolling blade is applied while hitting the gauge block, there is also the problem of overloading the press device and shortening the life of the press.

In the case of ■, the stroke amount is adjusted for each stroke, so the pressure oil is supplied and discharged in each cycle, and the energy used to supply the pressure oil is discharged without being recovered. The problem is that the loss is large.

In the case of (2), there is a problem in that the weight of the press device increases, making it expensive, and there is no countermeasure that can be taken in the case of a press device equipped with a hydraulic stroke adjustment mechanism.

In the case of (2), there is a problem in that the press operation requires skill and it is not possible to automate the press.

This invention has been made in view of the problems of the prior art, and aims to provide a press stroke control method and device that can easily, inexpensively, and reliably control the press stroke to obtain a product of a predetermined size. It is something.

[Means for Solving the Problems] In order to solve the above-mentioned problems of the prior art, the press stroke control method of the present invention provides a press stroke control method using a mechanical drive mechanism to perform a constant press stroke, and a stroke adjustment mechanism to perform a necessary press stroke. When controlling the stroke of the press adjusted to the stroke, detect the error with respect to the set value of the press stroke end position of the previous stroke,
The present invention is characterized in that at least a part of the error is outputted to the stroke adjustment mechanism and controlled in the next press stroke.

Further, the press stroke control device of the present invention is a control device for controlling a press stroke that includes a mechanical drive mechanism that performs a constant press stroke and a stroke adjustment mechanism that adjusts the press stroke to a necessary press stroke. A stroke detector for detecting a stroke; a comparing means for determining a stroke error by comparing a stroke end position from the stroke detector with a predetermined stroke end position; and at least a portion of the stroke error from the comparing means. The present invention is characterized by comprising a control means for controlling the next press stroke by outputting it to the stroke adjustment mechanism.

[Function] According to this press stroke control method, the stroke end position of the previous press stroke is detected, the error between this and the set value is determined, and part or all of this error is applied to the next press stroke. Compared to the case where the correction is performed every press cycle, the press stroke can be easily adjusted without applying the reduction blade, and products with good dimensional accuracy can be obtained.

Further, according to this press stroke control device, it is composed of a stroke detector that detects a press stroke, a means for comparing the detection result with a set value, and a control means, and the error caused by the previous press stroke is corrected for the next press stroke. During a press stroke, a correction signal is output from the control means to the stroke adjustment mechanism to adjust the stroke. Compared to the case where the stroke is adjusted for each press cycle, it is easier to press without applying any reduction blades. The stroke can be adjusted, the device is simple and inexpensive, and a product with good accuracy over a wide range can be obtained.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 1 and 2 are a schematic configuration diagram (I-1 sectional view in FIG. 2) and a cut front view of the forging press according to an embodiment in which the press stroke control device of the present invention is applied to a forging press device. It is.

The configuration of the forging press apparatus 1 provided with this press stroke control device is as already explained as the prior art.

This press stroke control device 30 is provided with a stroke detector 31 for detecting a press stroke S.

As shown in FIG. 2, this stroke detector 31 may be constructed by attaching a rack 32 to the top frame 4, for example, as shown in FIG.
A pinion 33 that meshes with this is attached to the bed 2, a rack 34 is attached to the reduction cylinder 15, a pinion 35 that meshes with this is attached to the bottom frame 5, and an encoder 36 is attached to each pinion 33, 35. It is constructed in this way.

Furthermore, a rotary encoder 37 that detects the rotation angle e is connected to the eccentric shaft 11 of the mechanical drive mechanism 10 that mechanically performs a constant press stroke.

Therefore, as shown in FIG. 5, if the rotation radius of the eccentric shaft 11 is r, the relationship between the current position Y and the stroke end position (bottom dead center position) H is determined by the rotation angle e of the eccentric shaft 11. It can be expressed by the following formula.

X-r-rcos e-r (1-cos e)
~(L)Y-H+Y-H+ r (1-cos e)
~(2) Such a detection signal of the stroke detector 31 is manually inputted to a comparator 38 constituting a comparison means.

The comparator 38 determines the stroke end position (upper anvil 8
h (bottom dead center position) is set as a set value, and the error ΔH at the press stroke end position is determined from this difference (h-H).

The error ΔH in the press stroke end position determined by the comparator 38 is manually input to three controllers constituting the control means.

This controller 39 outputs part or all of the press stroke error ΔH as a correction amount as a correction control signal to the stroke adjustment mechanism 13 during the next press stroke.

That is, it is output as a control signal for controlling the supply or discharge of pressure oil to the reduction cylinder 15 that constitutes the stroke adjustment mechanism 13, but the specific control signal is as follows.
For example, by opening and closing the solenoid valve 22, the amount of movement (distance D) of the ram 16 of the compression cylinder 15 can be directly adjusted, the opening and closing time of the solenoid valves 22 and 23 can be adjusted, or the pressure oil to the compression cylinder 15 can be adjusted. The solenoid valve 22 for supplying and discharging is operated for a predetermined short time t.
The opening/closing operation is repeated in a pulse-like manner, and a signal or the like is outputted to control and adjust the number of opening/closing operations.

Next, regarding the operation of the press stroke control device 30 configured as described above and the stroke control method,
This will be explained with reference to the drawings.

(1) Basic control method of press stroke.

In this press stroke control method, as shown in FIG. 3, the reciprocating movement of the eccentric shaft 11 of the mechanical drive mechanism 10 is performed based on a sine curve. The stroke is detected and the detection result is input to the comparator 38.

Then, the controller 39 uses the errors ΔH1, H2, Hn-1 generated by the previous press stroke to perform the next press stroke.
All or part of the value is output to the stroke adjustment mechanism 13 as a correction value.

The stroke adjustment by the stroke adjustment mechanism 13 is performed when the forging press device 1 is in a no-load state during the reciprocating movement of the eccentric shaft 11.

That is, during a certain press stroke, if the stroke end position is Hl above the preset predetermined press stroke h and the error is ΔH1, then during the next press stroke, the press stroke end position is moved by Hl above the preset predetermined press stroke h. Lower the position.

The setting of this Hl is calculated using the equations (1) and (2) already explained.
Accordingly, the corrected current position Y1 can be obtained as the following equation.

Yl −H−Hl + r (1+CO3e)
- (3) Therefore, it is only necessary to satisfy this formula (3), and the detected value of the stroke detector 31 and the detected value of the rotation angle e of the eccentric shaft 11, the predetermined eccentric shaft 1
It is possible to cross H by the radius r of 1 and the bottom dead center position H.

In addition, the ram 16 of the reduction cylinder 15 and the bottom frame 5
When detecting the stroke between the
All you have to do is operate it, and it can be easily adjusted.

By repeating such press stroke error detection and adjustment and correcting the next press stroke based on the previous press stroke, a product with good one-note precision can be obtained.

Furthermore, since the stroke adjustment is performed in a no-load state, the stroke can be easily and accurately controlled.

(2) Movement amount control of the stroke adjustment mechanism 13 based on press stroke errors.

In this case, as shown in FIG. There is something τ that is controlled by outputting it as a quantity.

Therefore, as explained in the basic control, when the stroke is directly detected by the stroke detector 31 as the amount of movement of the internal sliding body 5, the opening and closing of the Renoit Halb 22 is feedback controlled based on the detected value of the stroke detector 31. All you have to do is do this.

In addition, if stroke detection is performed from other parts, use formula (1) to calculate the current position Y of the press stroke.
, (2), the amount of movement to be corrected may be calculated using equation (3).

When correcting the next press stroke by controlling the movement amount of the stroke adjustment mechanism 13, the stroke correction amount is determined depending on the error size of the actual stroke end position with respect to the set value of the stroke end position. It can also be changed and controlled.

For example, the amount of movement (KXHI) to be corrected is calculated by multiplying the error H1 by the coefficient K, and if the error H1 is 20111 m or more with respect to the set value, K = 05,
If the error H1 is less than 20m+++ or more than 5ff111, set K = 0.8, and if the error H1 becomes smaller than 51, set K-1, and change the amount of movement according to the progress of forging. .

By changing the amount of movement of the stroke adjustment mechanism 13 in accordance with the magnitude of the error in this way, forging can be carried out efficiently and products with good dimensional accuracy can be obtained in a short time.

Note that the correction amount that changes depending on the magnitude of the error is not limited to the case where a stepwise value is used as a coefficient, and it may be a variable that changes based on a curve such as a quadratic function.

By controlling the amount of movement of the stroke adjustment mechanism 15 based on the stroke error in this way, the press stroke can be easily adjusted and a product with good dimensional accuracy can be obtained.

(3) Solenoid valve 22 for supplying and discharging the pressure surface to the stroke adjustment mechanism 13 due to press stroke errors.
Control by opening/closing time of 23.

The amount of pressure bending supplied to or discharged from the stroke adjustment mechanism 13 of this press stroke is controlled by the solenoid valve 22.2.
The position of the internal sliding body 15 of the compression cylinder 15 can be changed by changing the opening and closing times of these solenoid valves 22 and 23.

Therefore, as shown in FIG. 6, a control signal from the controller 39 based on the errors ΔH1, H2, .
It is controlled by outputting the opening/closing time t.

Therefore, as explained in the basic control, the press stroke is detected by the stroke detector 31, and based on the error from the set value, the opening/closing time of the solenoid valves 22 and 23 is calculated from a function or table determined in advance through experiments. is determined and outputted from three controllers to control the amount of pressure oil supplied to the reduction cylinder 15.

In this case, it is preferable to change the opening/closing time of the solenoid valves 22, 23 depending on the magnitude of the errors H1, H2, etc. For example, the error H1 is multiplied by a coefficient Kl to obtain the control time. , if this coefficient is set to 1, and the error H1 is 20 mm or more, Kl =
al, and when the error H1 is less than 20111ff1 and more than 5mm, it is set as Kl -a2, and when the error HL becomes small, 5mm or less, it is set as Kl-a3, and the opening and closing time is set according to the degree of progress of forging. change.

By changing the opening/closing time t of the solenoid valves 22 and 23 of the stroke adjustment mechanism 13 in accordance with the forging stage in this way, forging can be carried out efficiently and products with good dimensional accuracy can be obtained in a short time. .

Note that the correction amount that changes depending on the size of the error is not limited to the case where a stepwise value such as 1 is used as a coefficient, but it may be a variable that changes based on a curve such as a quadratic function.

By controlling the opening/closing time t of the solenoid valves 22 and 23 of the stroke adjustment mechanism 15 based on the stroke error in this way, the press stroke can be easily adjusted and a product with good dimensional accuracy can be obtained.

(4> Solenoid valve 22 for supplying and discharging pressure oil to the stroke adjustment mechanism 13 due to press stroke errors.
Control by number of opening and closing of 23.

Solenoid valve 22.2 that supplies or discharges pressure oil to the stroke adjustment mechanism 13 of this press stroke.
3 is configured such that activation and stopping are repeated for a certain period of time tl,
As shown in Figure 7, 1. These solenoid valves 22;
By controlling the number of operations N of the solenoid valve 23, the error ΔH1, H2, . Control by outputting as .

Note that such press stroke control is not analog control as described above, but digital control, and comparator 3
8 and the controller 39 can be changed to those compatible with digital control.

In this press stroke control, as explained in the basic control, the press stroke is detected by the stroke detector 31, and based on the error from the set value,
The number of times N of opening and closing of the solenoid valves 22 and 23 is determined from a function or table determined in advance through experiments, and this is output from the controller 39 to control the amount of pressure oil supplied to the compression cylinder 15.

In this case, it is preferable that the number of times N of opening and closing the solenoid valves 22 and 23 is also changed depending on the stage of forging.
For example, the error H1 is multiplied by a coefficient of 2 to determine the control time, and this coefficient is set to 2 to set the error H1.
If 1 is 20nv or more, set it as K2-bl and calculate the error H
If 1 is less than 201WI11 or more than 5■, K2-
b2, and when the error H( becomes small to 5III1 or less, it is set to K2-b3, and the number of openings and closings N is changed depending on the degree of progress of forging.

By changing the number of openings and closings N of the solenoid valves 22 and 23 of the stroke adjustment mechanism 13 in accordance with the forging stage in this way, forging can be carried out efficiently and products with good dimensional accuracy can be obtained in a short time. .

Note that the correction amount that changes depending on the forging stage is not limited to using a stepwise value such as 2 as a coefficient, but may be a variable that changes based on a curve such as a quadratic function.

Also, the opening/closing time t per solenoid valve 22, 23 for the error detected in the previous press stroke
It is also possible to change the opening/closing time t of the solenoid valves 22 and 23 as described in (3), in addition to controlling the number of times N of opening and closing the solenoid valve 2223. It becomes something.

By controlling the number N of openings and closings of the solenoid valves 22 and 23 of the stroke adjustment mechanism 15 based on the stroke error in this way, the press stroke can be easily adjusted and a product with good dimensional accuracy can be obtained. .

As described above, by controlling the press stroke in any of cases (1) to (4), the error caused by the previous press stroke is corrected during the no-load state of the next press stroke, and the error caused by the previous press stroke is corrected during the no-load state of the next press stroke. Since the next press stroke is repeated, there is no energy loss, and the press stroke can be controlled without requiring an expensive hydraulic circuit. Of course, if there is no time available, it is possible to perform correction even under load conditions.

Furthermore, automatic operation of the forging press equipment becomes easier.

Next, another embodiment of the stroke control device for a press according to the present invention will be described with reference to FIG.

This device is provided with an independent hydraulic system 40 for supplying and discharging pressure oil to the stroke adjustment mechanism 13, and other parts are the same as the structure shown in FIG. 1 already described.

This hydraulic system 40 is branched into the pipe line 21 and includes a plunger pump 42 driven by a hydraulic cylinder 41.The amount of movement of the plunger is detected by a movement amount detector 43 and inputted to a controller 39 (not shown). It is supposed to be done.

A switching valve 44 is provided to control supply and discharge of pressure oil to the hydraulic cylinder 41 and is connected to a hydraulic drive source 45 and an accumulator 46 .

By providing the hydraulic system 40 configured in this way,
When correcting the error caused by the previous press stroke in the next press stroke, the supply of the pressure section to the reduction cylinder 15 is controlled by the amount of movement of the plunger of the plunger pump 42, so that the already explained stroke adjustment can be achieved. It can be controlled in the same way.

The switching valve 44 in this case may be controlled by any of the methods (1) to (4) described above.

Next, another embodiment of a press to which the present invention is applied, in which a constant press stroke is performed by a mechanical drive mechanism and the press stroke is adjusted to a necessary press stroke by a stroke adjustment mechanism, will be described with reference to FIG.

This press device 50 has a bed 51 fixed to the foundation.
It is equipped with This bed 51 has a pair of columns 52.
．． A movable frame 55 is constructed by connecting a top frame 53 and a bottom frame 54 at their upper and lower ends, with a lifting cylinder 56 interposed between the bed 51 and the bottom frame 54. It supports the movable frame 55 and moves it up and down.

Anvils 5758 as forging tools are attached to the lower surface of the top frame 53 and the upper surface of the bed 5↑, respectively.

In order to apply the reduction blade via such a movable frame 55, an eccentric shaft mechanism is provided as a constant stroke mechanical drive mechanism 59 on the foundation outside the bed 51, and the rotationally driven eccentric shaft 60 moves the inside of the cylinder 61. Plunger 6
2 is designed to be reciprocated with a constant stroke.

On the other hand, a lowering cylinder 64 is provided between the bed 51 and the bottom frame 54 to constitute a stroke adjustment mechanism 63, the cylinder part is attached to the bed 51, and an internal sliding body 65 that slides therein is attached to the bottom frame 54. is connected to.

The reduction cylinder 64 and the cylinder 61 are communicated with each other through a pipe 66, so that pressure oil can be supplied and discharged.

Therefore, when the eccentric shaft 60 is rotated, the planer/jar 6
Pressure oil is made in cylinder 61 by 2, and this or piping 6
6 to the compression cylinder 64.

Therefore, the movable frame 55 is pushed down and pressing such as forging is performed.

In the case of controlling the press stroke, although not shown, it can be done by controlling the supply and discharge of pressure oil to the reduction cylinder 64.

In this way, the present invention can be similarly applied to a mechanical drive mechanism 59 disposed separately from the press device.

In the above embodiment, a solenoid valve is used, or a servo valve with higher responsiveness may be used.

Further, the application is not limited to forging press equipment, but can be similarly applied to other press equipment.

Furthermore, in the above embodiment, the stroke adjustment mechanism of the press was explained using a hydraulic mechanism, but this is not limited to this, and the application can be similarly applied to a mechanical stroke adjustment mechanism such as a screw. What is necessary is to control the amount, rotation speed, etc.

Furthermore, it goes without saying that each component may be changed without departing from the gist of the invention.

[Effects of the Invention] As described above in detail with the embodiments, ■ According to the press stroke control method of the present invention, the stroke end position of the previous press stroke is detected, and the error between this and the set value is corrected. This error is then corrected for part or all during the next press stroke, so the press stroke can be adjusted more easily without the reduction blade being applied, compared to when it is done for each press cycle. You can get products with good precision.

■ According to the press stroke control method of this invention,
The press stroke can also be adjusted by controlling the travel distance of the stroke adjustment mechanism.

■ According to the press stroke control method of this invention,
The press stroke can also be adjusted by controlling the adjustment time of the stroke adjustment mechanism.

■ According to the press stroke control method of this invention,
The press stroke can also be adjusted by controlling the number of activations of the stroke adjustment mechanism.

■ Also, according to the stroke control device of this press,
Compared to the case where the stroke is adjusted for each press cycle, the press stroke can be easily adjusted without applying a reduction blade, the device is simple and inexpensive, and products with good dimensional accuracy can be obtained.

Therefore, there is no need to prepare block gauges according to the dimensions of the product, and there is no need to replace them each time, so work efficiency is improved and productivity can be improved.

In addition, it can be operated even by non-skilled operators.
Furthermore, a highly accurate product can be obtained.

Furthermore, since the press device itself corrects errors in the press stroke, automation is easy.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are a schematic configuration diagram (1-1 sectional view in FIG. 2) and a cutaway front view of the forging press according to an embodiment in which the press stroke control device of the present invention is applied to a forging press device. It is. 3 to 7 are explanatory diagrams of the principle of the press stroke control method of the present invention, respectively. FIG. 8 is a schematic diagram of another embodiment in which the press stroke control device of the present invention is applied to a forging press device. FIG. 9 is a cutaway front view of an example of a press device to which the present invention is applied. 1: Forging press device, 2 needles, 3: Column, 4 needles frame, 5: Bottom frame, 6: Movable frame, 7: Lifting cylinder, 8° 9: Anvil, 10: Mechanical drive mechanism, 11: Eccentric shaft, 12 Pitman arm,
13: Stroke adjustment mechanism, 14 guide portion, 15. Reduction cylinder, 16, Ram, 17: Push rod, 18
・Lifting cylinder, 1: Hydraulic drive source, 20. Accumulator, 21: Pipeline, 22.23: Solenoid valve, 2
4, Branch pipe, 25 Niaccumulator, 26°27 Solenoid valve, 30: Stroke control device, 31 Nistroke detector,
38. Comparator (comparison means), 3: controller (control means)
, S: Stroke, H2 stroke end/position, h: Set value, Hl-Hn-1: Error, N: Opening/closing number, t: Opening/closing time, g, Travel distance.

Claims (5)

[Claims] (1) When a mechanical drive mechanism performs a press stroke of a certain length and a stroke adjustment mechanism controls the press stroke, an error with respect to the set value of the press stroke end position of the previous stroke is detected, and the next press stroke is A press stroke control method, characterized in that at least a part of the error is outputted to the stroke adjustment mechanism for control. (2) The press stroke control method according to claim 1, wherein the moving distance of the stroke adjustment mechanism is controlled according to the error between the press stroke end position and the set value. (3) The press stroke control method according to claim 1, wherein the adjustment time of the stroke adjustment mechanism is controlled according to the error between the press stroke end position and the set value. (4) The stroke control of the press according to claim 1, wherein the number of operations of the stroke adjustment mechanism, which repeatedly stops operating in a certain period of time, is controlled according to the error between the press stroke end position and the set value. Method. (5) a mechanical drive mechanism that performs a constant press stroke;
In a control device for controlling the stroke of a press that is equipped with a stroke adjustment mechanism that adjusts to a required press stroke, a stroke detector that detects a press stroke and a comparison means that determines a stroke error in a stroke end position from the stroke detector. 1. A press stroke control device comprising: and a control means for controlling a stroke error from the comparison means.