JPH042360B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a hydraulic press device, and more specifically, a press cylinder presses a movable platen against a fixed platen, and a hydraulic press device is installed between the fixed platen and the movable platen. The present invention relates to a hydraulic press device that controls pressing of a predetermined workpiece between pressed press plates according to a predetermined program.

(Prior art and its problems) In a hydraulic press device, a movable platen is pressed against a fixed platen using a pressure cylinder, and a predetermined amount of pressure is applied between the press plates disposed between the fixed platen and the movable platen. There is a method in which pressing of a workpiece is controlled according to a predetermined program. For example, a hydraulic press device is used for press-molding laminated printed wiring boards, laminated printed multilayer boards, etc.

By the way, in such a hydraulic press device, when performing pressing control on a workpiece, it is necessary to determine the start time of the pressing control.
In conventional hydraulic press equipment, a position or distance sensor such as a limit switch or a photoelectric switch detects when the movable platen has reached a predetermined pressing start position, and starts pressing control based on the detection result. Since the timing was determined, there was a problem in that the timing to start the clamping control was likely to vary depending on the subjectivity of the operator.

In addition, in conventional hydraulic press equipment, the pressing control (pressure control) of the workpiece is based on controlling only the hydraulic pressure of the hydraulic fluid of the pressing cylinder or the surface pressure acting on the workpiece. In addition, the start timing of the pressing control is likely to vary, especially in pinless molding of laminated printed multilayer boards where the laminated materials constituting the workpiece are not temporarily fixed with pins. There was a problem that variations in the thickness of press-formed products were likely to occur.

(Solution Means) The present invention was made against the background of the above, and its gist is to press the movable platen against the fixed platen with a pressing cylinder as described above, and to press the movable platen against the fixed platen. In a hydraulic press device that controls pressing of a predetermined workpiece according to a predetermined program between a press plate disposed between a press cylinder and a movable platen, (a) the press cylinder (b) a detection means for detecting that the movable platen has reached a predetermined clamping start position based on the hydraulic pressure detected by the sensor; It is composed of an electromagnetic relief valve connected to the hydraulic oil supply passage to the cylinder, and controls the hydraulic pressure of the hydraulic oil supplied to the clamping cylinder according to a set surface pressure control pattern, and applies pressure to the workpiece. and (c) an electromagnetic flow control valve connected to the hydraulic oil supply passage to the clamping cylinder, according to a set plate thickness control pattern. distance control means for controlling the distance between the press plates by controlling the amount of hydraulic fluid entering the pressing cylinder, and the detecting means detects when the movable platen reaches the pressing start position. By detecting this and starting the clamping control, one of the surface pressure control means and the distance control means is made to function as a limiter for the other. While setting a predetermined limit on the surface pressure exerted by the press plates or the distance between the press plates, the distance between the press plates or the surface pressure is controlled by the other of the surface pressure control means and the distance control means. The present invention is characterized in that the clamping control is performed by controlling.

Note that here, the distance control means does not necessarily have to directly control the distance between the press plates, and may also include one that indirectly controls the distance between the press plates based on the amount of variation thereof. should be interpreted.

(Action/Effect) According to the hydraulic press device according to the present invention,
Since the start timing of clamping control is determined based on the hydraulic pressure of the hydraulic fluid in the clamping cylinder, the clamping start position of the movable platen is detected using a position or distance sensor, and the pressure is controlled based on the detection result. This makes it possible to avoid variations in the starting timing of the clamping control depending on the subjectivity of the operator, which is the case with conventional devices that determine the timing of starting the clamping control.

Further, according to the hydraulic press device according to the present invention,
A surface pressure control means for controlling the surface pressure acting on the workpiece, and a distance control means for controlling the distance between the press plates, that is, the thickness of the workpiece, and either one of them is provided. is made to function as a limiter for the other, and one of them sets a predetermined limit (monitoring width) on the surface pressure acting on the workpiece or the distance between the press plates, while the other press Since it is now possible to perform pressure control (pressure control) on the workpiece by controlling the distance between the plates or the surface pressure acting on the workpiece, the workpiece (press-formed product) can be When clamping a workpiece is controlled by controlling the distance between press plates corresponding to the plate thickness, it is possible to effectively prevent excessive hydraulic pressure from acting on the clamping cylinder. At the same time, it is possible to control the clamping of the workpiece, and it is also possible to control the clamping of the workpiece by controlling the surface pressure on the workpiece, that is, the hydraulic pressure of the compression cylinder. Therefore, it is possible to control the pressing of the workpiece while preventing the thickness of the workpiece from becoming thinner than necessary.

Therefore, it is possible to control the pressing of the workpiece while effectively preventing the workpiece from becoming thinner than a predetermined plate thickness, and the variation in the start timing of the pressing control can be effectively suppressed. In addition to being able to avoid this, it is possible to effectively control the variation in thickness of press-formed products, especially laminated printed multilayer boards formed by pinless molding, and to stably produce press-formed products with high thickness accuracy and good quality. It can be molded by

(Example) Hereinafter, in order to clarify the present invention more specifically, one example thereof will be described in detail based on the drawings.

Here, we will discuss an example in which the present invention is applied to a so-called multi-stage press device that simultaneously press-forms a plurality of workpieces between a plurality of press plates arranged between a fixed platen and a movable platen. state

First, in FIG. 1, reference numeral 10 denotes a stationary plate, which is fixedly attached to the upper end of a stay 13 erected on a base 11. Also, 12
is a movable platen and is attached to the ram 16 of the clamping cylinder 14 disposed on the base 11.
And here, those fixed platen 10 and movable platen 1
2, a plurality of hot plates 18 as press plates are arranged, and by raising the ram 16 of the clamping cylinder 14 and pressing the movable platen 12 against the fixed platen 10. , between each hot plate 18, a plurality of workpieces 20 of a predetermined press-formed product such as a laminated printed wiring board or a laminated printed multilayer board can be simultaneously hot-pressed.

By the way, in such a multi-stage press device, as shown in the figure, when the movable platen 12 is in its lowered position, a predetermined gap is formed between each of the workpieces 20 and each of the hot plates 18 directly above them. However, here, a predetermined gap is also formed between the uppermost hot plate 18 and the fixed platen 10, and when press forming the workpiece 20, the movable platen 12 is raised from its lowered position, the gaps between them are sequentially eliminated starting from the lowermost one, and the uppermost heating plate 18 and fixed plate 1
The gap between 0 and 0 is made to disappear at the end. In other words, the top heating plate 18 and the fixed plate 1
0 is eliminated, the movable platen 12 comes into indirect contact with the fixed platen 10, and in this embodiment,
This is detected by a limit switch 22 attached to the stationary platen 10.

The limit switch 22 is pressed and operated by a dog 24 attached to the uppermost heating plate 18. Although not shown in the drawings, each of the hot plates 18 includes
A balance cylinder is installed to cancel the weight of.

In addition, in such a multi-stage press device, after the movable platen 12 and the fixed platen 10 come into indirect contact, the movable platen 1
2 is further raised, the movable platen 12
is pressed against the fixed platen 10, and as a result, a pressing operation is performed on the workpiece 20 between the respective hot plates 18, 18. In this embodiment, the heat generated during the pressing operation is The distance between the plates 18, 18, that is, the thickness (plate thickness) of the workpiece (press-formed product) 20, has a sufficiently high accuracy due to the linear position sensor 26 using a proximity switch attached to the movable platen 12. It is becoming more and more detected.

In addition, this linear position sensor 26 accurately measures the distance between the hot plate 18 fixed to the movable platen 12 and the shielding plate 28 fixed to the hot plate 18 that presses the workpiece 20. It is now possible to detect
As will be described later, the amount of variation in the distance between the hot plates 18, 18, that is, the amount of variation in the thickness of the workpiece 20 is detected.

Further, although the linear position sensor 26 is attached to the movable platen 12 having a low ambient temperature here, it can also be used by attaching it to the fixed platen 10 or the hot plate 18. In addition to the linear position sensor 26, it is also possible to use a rotary encoder, potentiometer, linear scale, etc. as a sensor for detecting the thickness (amount of variation in plate thickness).

On the other hand, in the multi-stage press apparatus of this embodiment, the hydraulic oil pumped up by the pump 30 is supplied to the oil chamber 33 of the clamping cylinder 14 via the electromagnetic switching valve 32, as in the conventional case. 16, that is, the movable platen 12 is raised, and an electromagnetic relief valve 36 is connected to the oil chamber 33 of the clamping cylinder 14 via an electromagnetic switching valve 34.
However, an electromagnetic flow control valve 40 is also connected via the electromagnetic switching valve 38, and the electromagnetic switching valve 34
Under the excitation state, the working oil pressure in the oil chamber 33,
Furthermore, the surface pressure on the workpiece 20 during the pressing control of the press device can be controlled by the electromagnetic relief valve 36, and when the electromagnetic switching valve 38 is energized, the oil chamber is removed from the pump 30. 33, and the plate thickness of the workpiece (press-formed product) 20 (distance between the hot plates 18 and 18) during the pressing control of the press device.
can be controlled by an electromagnetic flow control valve 40.

Note that the rising speed of the movable platen 12 is controlled based on the control of the amount of hydraulic oil flowing into the oil chamber 33 by the electromagnetic flow control valve 40, so that the movable platen 12 is fixed. It is designed so that it can be brought into contact with the board 10 at a slow speed.

Further, an oil pressure sensor 42 is also connected to the oil chamber 33 of the clamping cylinder 14, and the working oil pressure in the oil chamber 33, and thus the workpiece 20 during clamping control.
The surface pressure can be detected by this oil pressure sensor 42.

Here, as mentioned above, the movable plate 12
After the limit switch 22 detects that the contact surface indirectly contacts the fixed platen 10, the electromagnetic relief valve 36 is controlled to be energized according to the surface pressure control pattern set by the surface pressure control pattern setting device 44. By controlling the electromagnetic flow rate control valve 40 in accordance with the plate thickness control pattern set by the plate thickness control pattern setter 46, the workpiece 20 is controlled between the hot plates 18, 18 according to the control pattern. The clamping control can be performed according to the following.

That is, the movable platen 1 is
2 is moved upward, and the uppermost heating plate 18 is moved to the fixed plate 1.
0 and the movable platen 12 indirectly contacts the fixed platen 10, the limit switch 22 outputs a contact detection signal S1, and the contact detection signal
S1 is adapted to be supplied to a differentiator 48.
The differentiator 48 also includes the working pressure in the oil chamber 33 of the clamping cylinder 14 detected by the hydraulic pressure sensor 42 (hereinafter simply referred to as the working pressure of the clamping cylinder 14).
A hydraulic signal S2 representing the pressure is supplied. The differentiator 48 then switches the limit switch 2
After inputting the contact detection signal S1 from 2, the hydraulic signal S2,
That is, the working pressure of the clamping cylinder 14 is differentiated, and the differential value of the working pressure is compared with a predetermined reference value, and when the differentiated value matches the reference value, the plate thickness variation amount calculator 50 and the control pattern setters 44 and 46, respectively, to start the clamping control on the workpiece 20.

In such a multi-stage press device, as described above, after the movable platen 12 comes into indirect contact with the fixed platen 10, when the movable platen 12 is further raised to press the workpiece 20, the workpiece At the time of transition of the object 20 to the clamped state, surface pressure on the workpiece 20,
As a result, the hydraulic pressure of the clamping cylinder 14 increases rapidly. Therefore, here, the time when the working pressure of the clamping cylinder 14 suddenly increases is detected by the differentiator 48, and as will be described later, the pressure output from the differentiator 48 is detected. By operating the surface pressure control pattern setter 44 and plate thickness control pattern setter 46 based on the tightening control start signal S3, the workpiece 20
The clamping control is performed according to the control pattern set by the setting devices 44 and 46. As is clear from the above description, here, the hydraulic pressure sensor 42 that detects the working pressure of the clamping cylinder 14 and the differentiation that differentiates the hydraulic pressure signal S2 from the hydraulic pressure sensor 42 and outputs the clamping control start signal S3 are used. The device 48 constitutes a detection means for detecting that the movable platen 12 has reached the clamping start position.

Although not shown, the clamping control start signal S3 output from the differentiator 48 is also supplied to the heating control circuit of the hot plate 18, so that each heat control circuit is controlled by the heating control circuit. Heating control of the plate 18 is started at the same time. Also,
In the figure, 52 is an A/D converter.

Here, the plate thickness variation calculation unit 50 to which the clamping control start signal S3 from the differentiator 48 is inputted,
The linear position sensor 26 is connected via an A/D converter 54, and the measurement result from the linear position sensor 26 is transmitted to the shielding plate 2.
A distance signal S4 representing the distance between the two is inputted. Then, the plate thickness variation calculation unit 5
0 is the amount of deviation from the reference value S ₀ based on the content S ₀ of the distance signal S4 at the time when the clamping control start signal S3 from the differentiator 48 is input, that is, the deviation from the clamping control start time. The variation amount ΔS in the plate thickness of the workpiece 20 is determined in real time, and a plate thickness variation signal S5 representing the plate thickness variation amount ΔS is supplied to the comparator 56.

Further, a clamping control start signal from the differentiator 48
In the plate thickness control pattern setter 46 to which S3 is input, a predetermined plate thickness control pattern (more precisely, plate thickness variation control pattern) as shown in FIG. 2 is set and stored. When the plate thickness control pattern setter 46 receives the clamping control start signal S3 from the differentiator 48, it starts outputting a target plate thickness variation signal S6 according to the plate thickness control pattern, and compares The water is supplied to a container 56.
Note that the board thickness control pattern is usually displayed on a predetermined image display device such as a CRT, and is set in a visible state.

In addition, the comparator 56 compares the plate thickness variation signal S5 from the plate thickness variation calculation unit 50 and the target plate thickness variation signal S6 from the plate thickness control pattern setter 46,
It is designed to output a plate thickness correction signal S7 according to the difference between them, and the plate thickness correction signal S7 is sent to D/
A converter 58 and analog output card 60
It is designed to supply the solenoid of the electromagnetic flow control valve 40 via the solenoid. The electromagnetic flow control valve 40 is configured to control its valve opening depending on the magnitude of the plate thickness correction signal S7 supplied from the comparator 56.
The amount of hydraulic oil flowing into the clamping cylinder 14 is controlled so that the plate thickness variation signal S5 at step 6 coincides with the target plate thickness variation signal S6.

That is, the electromagnetic flow control valve 40 has a differentiator 48
When the clamping control start signal S3 is output from the clamping cylinder, the clamping cylinder is operated so that the actual plate thickness variation ΔS of the workpiece 20 matches the plate thickness control pattern set by the plate thickness control pattern setter 46. The amount of hydraulic oil flowing into the plate 14 is controlled, thereby making it possible to control the pressing of the workpiece 20 in accordance with the plate pressure control pattern. Note that, as is clear from the above description, in this embodiment, the electromagnetic flow control valve 40 is connected to the hot plate 1.
8 and 18 constitutes distance control means for controlling the distance between them.

On the other hand, the clamping control start signal from the differentiator 48
A predetermined surface pressure control pattern as shown in FIG. 3 is set and stored in the surface pressure control pattern setter 44 to which S3 is supplied. When the pressure control pattern setting device 44 receives the clamping control start signal S3 from the differentiator 48, it outputs a target surface pressure signal S8 according to the surface pressure control pattern to the hydraulic calculator 62. I'm starting to do that. Note that, like the plate thickness control pattern, the surface pressure control pattern is normally displayed on a predetermined image display device and set in a visible state.

The hydraulic calculator 62 also includes a mechanical constant setting device 6.
4 is connected, and various data necessary for converting hydraulic pressure from surface pressure can be input. Then, based on the target surface pressure signal S8 supplied from the surface pressure control pattern setting device 44 and various data set by the mechanical constant setting device 64, the hydraulic calculator 62 calculates the surface that the target surface pressure signal S8 represents. The working oil pressure of the clamping cylinder 14 corresponding to the pressure is calculated, and a target oil pressure signal S9 representing the working oil pressure is supplied to the comparator 66. The comparator 66 compares the target oil pressure signal S9 with the oil pressure signal S2 from the oil pressure sensor 42, and outputs an oil pressure correction signal S10 according to the difference between them.
S10 is supplied to the solenoid of the electromagnetic relief valve 36 via the D/A converter 68 and analog output card 70.

That is, here, the set oil pressure of the electromagnetic relief valve 36 is the oil pressure correction signal output from the comparator 66.
S10 is adapted to be corrected, so that the hydraulic pressure of the clamping cylinder 14 and, by extension, the surface pressure on the workpiece 20 can be controlled in accordance with the surface pressure control pattern. It is being done. Note that, as is clear from the above description, in this embodiment, the electromagnetic relief valve 36 constitutes surface pressure control means.

According to the multi-stage press device having such a configuration, as described above, the pressing start position (pressing control start timing) of the movable platen 12 is detected based on the working oil pressure of the pressing cylinder 14. Therefore, it is possible to avoid variations in the pressing control start timing due to operator's subjectivity, and moreover, there is no need to make troublesome adjustments each time according to differences in the thickness of the workpiece 20, etc. Since it is not necessary, it becomes possible to proactively promote automation and labor savings. Further, in this embodiment, as described above, the workpiece 20
The start timing of the clamping control for the clamping cylinder 14
Since it is determined based on the rate of change (differential value) of the hydraulic pressure, it is possible to avoid errors in the start timing of clamping control due to hydraulic oil temperature, etc. This also effectively prevents variations in the start timing of the clamping control.

Furthermore, as is clear from the above description, according to the multi-stage press apparatus having such a structure, the workpiece 20 can be pressed and controlled based on the control of the electromagnetic flow control valve 40 and the electromagnetic relief valve 36, so that the surface The surface pressure control pattern set by the pressure control pattern setter 44 is given as the upper limit value of the working pressure of the clamping cylinder 14, and while the electromagnetic relief valve 36 functions as a limiter of the working pressure, the plate thickness is By performing the clamping control of the workpiece 20 according to the plate thickness control pattern (plate thickness variation control pattern) set by the control pattern setting device 46, the surface pressure on the workpiece 20 increases abnormally. It is possible to control the pressing of the workpiece 20 while preventing this from occurring, and conversely, the control pattern of the plate thickness variation amount set by the plate thickness control pattern setting device 46 can be controlled by pressing the workpiece 20. is given as the upper limit of the amount of variation in plate thickness, and while the electromagnetic flow control valve 40 functions as a plate thickness limiter for the workpiece 20, the workpiece is controlled according to the surface pressure control pattern set by the surface pressure control pattern setter 44. By controlling the pressing of the workpiece 20, the thickness of the workpiece 20 can be effectively prevented from becoming excessively thin.
It is possible to control the clamping.

That is, in the multi-stage press apparatus having such a structure, control by the electromagnetic relief valve 36 as a surface pressure control means and control by the electromagnetic flow control valve 40 as a distance control means are selectively performed, and the control by the electromagnetic relief valve 36 and the electromagnetic flow rate control means is performed selectively. Either one of the control valves 40 is made to function as a limiter for the other, and in that case, one of the control valves 40 is generally provided with a certain tolerance to avoid excessive response. (monitoring width) is given, and therefore a predetermined limit (monitoring width) is applied to the surface pressure applied to the workpiece or the distance between the press plates, while the other The distance or the surface pressure will be controlled.

As described above, according to the multi-stage press apparatus of this embodiment, the electromagnetic flow control valve 40 and the electromagnetic relief valve 3
6 as a limiter for the other, the surface pressure on the workpiece 20 may increase abnormally, and the thickness of the workpiece (press-formed product) 20 press-formed between the hot plates 18, 18. It is possible to control the pressing of the workpiece 20 while preventing the material from becoming excessively thin. Therefore, in addition to being able to suppress variations in the start timing of the pressing control, it is also possible to use the pinless forming method. This makes it possible to satisfactorily suppress variations in the thickness of press-formed products, such as laminated printed multilayer boards that are press-formed using a press-forming method, and to stably produce high-quality press-formed products.

In addition, in this embodiment, as mentioned above, the movable platen 1
2 is controlled by the electromagnetic flow control valve 40, and the movable platen 12 is brought into contact with the fixed platen 10 at a slow speed. The advantage is that the thickness accuracy of molded products can be improved.

Further, in the multi-stage press apparatus of this embodiment, as described above, the electromagnetic relief valve 36 and the electromagnetic flow control valve 40 are connected to the oil chamber 33 of the pressing cylinder 14 via the electromagnetic switching valves 34 and 38, respectively. At the same time, since the electromagnetic relief valve 36 and the electromagnetic flow control valve 40 are made to communicate with the oil chamber 33 under the energized state of the electromagnetic switching valves 34 and 38, the movable platen 12 can be moved in the event of a power outage or the like. It has the advantage that falling can be well prevented, and by energizing only one of the electromagnetic switching valves 34 and 38, clamping control can be performed based only on surface pressure control or plate thickness control. There are some advantages to being able to do this.

Furthermore, in the multi-stage press apparatus of this embodiment, the thickness of the workpiece 20 (the distance between the hot plates 18, 18) is controlled based on the detection of the amount of variation in the thickness. Compared to directly controlling the thickness of the workpiece 20, this has the advantage that it is extremely easy to install a position or distance sensor for detecting the distance between the hot plates 18, 18, and There is an advantage that the thickness of the object 20 can be controlled with high precision.

Although one embodiment of the present invention has been described in detail above,
This is a literal example, and it goes without saying that the present invention should not be construed as being limited to this specific example.

For example, in the embodiment described above, the electromagnetic flow control valve 40 serving as the distance control means outputs the plate thickness variation signal S5 representing the actual plate thickness variation ΔS of the workpiece 20 from the plate thickness control pattern setter 46. The electromagnetic relief valve 36, which is a surface pressure control means, is controlled according to the difference between the target plate thickness variation signal S6 and the hydraulic pressure signal S2 representing the actual working pressure of the clamping cylinder 14. The control is performed according to the comparison difference with the target oil pressure signal S9 output from the oil pressure calculator 62, but on the side that is made to function as a limiter, it is directly controlled by the corresponding target signal S6 or S9. It is also possible to adopt a structure in which the electromagnetic flow control valve 40 or the electromagnetic relief valve 36 is controlled for open roof control.

Further, in the above embodiment, the target oil pressure signal S9 was supplied to the comparator 66 based on the surface pressure control pattern set by the surface pressure control pattern setting device 44. It is also possible to directly set the oil pressure control pattern and directly output the target oil pressure signal S9 from the setter and supply it to the comparator 66.

Furthermore, the differentiator 48 and the arithmetic unit 5 of the embodiment
Various calculations performed with 0, 62 etc. and comparator 5
The comparison operations performed at 6 and 66 can also be performed by a microcomputer.

Further, in the embodiment described above, an example in which the present invention is applied to a multi-stage press apparatus that performs hot press processing has been described, but the present invention is not limited to this, and only one workpiece 20 can be processed at a time. It is also possible to apply the present invention to a single-stage hydraulic press device that cannot be press-formed, and it is also possible to apply the present invention to a cold press device in which the press plate does not have a heating function. .

In addition, although it is omitted to list specific examples one by one, the present invention can be implemented with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art without departing from the spirit thereof. Of course.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an example of a multi-stage press apparatus according to the present invention, and FIGS. 2 and 3 respectively show the plate thickness control pattern and surface pressure control pattern set in the apparatus of FIG. It is a figure showing an example. 10: Fixed plate, 12: Movable plate, 14: Pressing cylinder, 18: Hot plate (press plate), 20: Workpiece,
22: Limit switch, 26: Linear position sensor, 36: Electromagnetic relief valve (surface pressure control means), 4
0: Electromagnetic flow control valve (distance control means), 42: Oil pressure sensor, 44: Surface pressure control pattern setter, 4
6: Plate thickness control pattern setter, 48: Differentiator, 5
0: Plate thickness variation calculator, 56, 66: Comparator, 6
2: Hydraulic calculator.

Claims (1)

[Claims] 1. Pressing the movable platen against the fixed platen with a clamping cylinder,
A hydraulic press device that controls pressing of a predetermined workpiece according to a predetermined program between press plates disposed between the fixed platen and the movable platen, the pressure a detection means having a hydraulic pressure sensor for detecting the hydraulic pressure of hydraulic oil in the clamping cylinder, and detecting that the movable platen has reached a predetermined clamping start position based on the hydraulic pressure detected by the sensor; and the clamping cylinder. The pressure relief valve is configured by an electromagnetic relief valve connected to the hydraulic oil supply passage to the workpiece, and controls the hydraulic pressure of the hydraulic oil supplied to the clamping cylinder according to a set surface pressure control pattern. and an electromagnetic flow control valve connected to the hydraulic oil supply passage to the clamping cylinder, and the clamping unit controls the clamping according to a set plate thickness control pattern. distance control means for controlling the distance between the press plates by controlling the amount of hydraulic fluid flowing into the cylinder, and the detection means detecting that the movable platen has reached the pressing start position. and starts the clamping control, and one of the surface pressure control means and the distance control means is made to function as a limiter of the other, thereby acting on the workpiece. By controlling the distance between the press plates or the surface pressure by the other of the surface pressure control means and the distance control means while setting a predetermined limit on the surface pressure or the distance between the press plates. , A hydraulic press device characterized in that the clamping control is performed.