JPH0731919Y2 - Mold contact position positioning device for press machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a press machine, particularly a hydraulic press, which is suitable for accurately positioning a contact position of a mold.

[Conventional technology]

In order to improve product accuracy in the hydraulic press, it is necessary to accurately position the contact position of the mold.

Here, the positioning of the contact position of the conventional mold has been performed as follows.

That is, the slide 2'of the hydraulic press 1'shown in FIG.
Is pushed downward by a predetermined load F by a hydraulic cylinder (not shown) to bring the upper die 3'and the lower die 4 'into contact with each other. On the other hand, if a sensor for detecting the load (pressure) of the hydraulic cylinder is provided and the detection value of this sensor reaches a value corresponding to the case where the upper die 3'and the lower die 4'contact each other, then at that time point. It is assumed that the upper die 3'and the lower die 4'contact each other, and the detection position of the incremental encoder 5'which detects the movement position of the slide 2'at the above-mentioned time point is set to the zero point. After that, the mold clamping process is executed with the set zero point as a reference position (mold contact position).

[Problems to be solved by the device]

However, when the upper die 3'and the lower die 4'are in contact with each other, the slide 2'and the bolster 6'bend upward and downward, respectively, as shown in FIG.
The bending deformation causes the slide 2'to bend W, that is, the original upper surface position 2a 'of the slide 2' (when the bending deformation does not occur).
A displacement W is generated between the curved upper end position 2c 'and the curved upper end position 2c'.
An error would occur at the zero point position (mold contact position) of.

In this way, the mold clamping process is performed with the accuracy of the zero point position deteriorated, so that the mold clamping process cannot be performed accurately.

The present invention has been made in view of these circumstances,
It is an object of the present invention to provide a device capable of accurately positioning a die contact position of a hydraulic press, and eventually a press machine, with high accuracy.

[Means for Solving the Problems]

Therefore, in the present invention, in a press machine including a bolster supporting a lower mold, a slide supporting the upper mold to move up and down, and an actuator for driving the slide,
Load detection means for detecting the load of the actuator,
Position detection means for detecting the movement position of the slide, control means for making the driving force of the actuator zero when the detected load of the load detection means exceeds a predetermined value, and driving of the actuator by the control means. When the detected load of the load detecting means becomes zero after the force is made zero,
A means for setting the detection position of the position detection means at this time as the contact position of the upper die and the lower die, and press working is performed based on the set contact position.

[Action]

That is, when the load detected by the load detecting means exceeds a predetermined value (when the upper die and the lower die are in contact), the driving force of the actuator is once made zero and the load of the actuator is removed. Therefore, the detection load of the load detection means becomes zero,
Elimination of slide and bolster deflection. Then,
At that time, the detection positions of the position detection means are set as the contact positions of the upper die and the lower die. Then, the bending error is removed, and the mold contact position is accurately positioned.

〔Example〕

An embodiment of a die contact position positioning device of a press machine according to the present invention will be described below with reference to the drawings.

FIG. 1 conceptually shows a configuration block diagram of the embodiment apparatus.
In the embodiments, a hydraulic press is assumed as the press machine.

As shown in the figure, the apparatus of the embodiment is roughly a hydraulic press 1.
And a sequence control circuit 3 which controls the hydraulic circuit 2 to position the die contact position of the hydraulic press 1 by controlling the hydraulic circuit 2.

The hydraulic press 1 includes a bolster 5 having a lower die 4 supported on an upper portion thereof, and an upper die 6 which is pressed by approaching the lower die 4 at a lower portion thereof, and a hydraulic cylinder arranged on four sides of an upper surface. A slide 11 that allows the upper die 6 to move up and down freely to the lower die 4 by the hydraulic pressures generated at 7, 8, 9 and 10.
Incremental encoders 12, 13, 14 for detecting the moving position of the slide 11 for each corner of the slide 11 and
It consists of 15 and.

On the other hand, the hydraulic circuit 2 is connected to a constant displacement type hydraulic pump 16 which is a drive source of the hydraulic cylinders 7, 8, 9 and 10 and a pressure oil discharge side of the hydraulic pump 16 so as to control the pressure of the discharge pressure oil. A pressure control valve (for example, a relief valve is used) 17 that limits the pressure below a set value, a pressure sensor 18 that detects the pressure of pressure oil whose pressure is limited by the pressure control valve 17, and a pressure control valve
Servo valves 19, 20, 21 and 17 for adjusting the flow rate of the pressure oil whose pressure is limited by 17 and supplying the pressure oil to the compression side or expansion side cylinder chambers of the hydraulic cylinders 7, 8, 9 and 10 respectively.
It is composed of 22 and.

Further, the sequence control circuit 3 controls the set pressure P2 of the pressure control valve 17 to be a desired pressure according to the input origin alignment signal ST and the output P1 of the pressure sensor 18, and outputs the clear signal CL. The valve control unit 23, the servo valve 19,
The flow rate of pressure oil output from 20, 21 and 22 is the desired flow rate Q _S
Servo valve control units 24, 24-1, 24 for servo-controlling the opening degrees of these servo valves 19, 20, 21 and 22 respectively.
-2 and 24-3 and the detection positions of the encoders 12, 13, 14 and 15 are respectively input, and while counting the pulse signals according to the input detection positions, the clear signal CL output from the pressure valve control unit 23 It is composed of counters 25, 25-1, 25-2 and 25-3 for aligning the origin (zero point) of the encoders 12, 13, 14 and 15 with the count value at the time of input being zero.

The operation of aligning the origins of the encoders 12, 13, 14 and 15 in such a configuration will be described with reference to the time chart of FIG. The hydraulic cylinder 7
˜10 represent the hydraulic cylinder 7, and encoders 12-15 represent the encoder 12 respectively.

As shown in the figure, the home position alignment signal ST indicates the servo valve control unit.
When input to 24, 24-1, 24-2 and 24-3 and the pressure valve control unit 23, the opening of the servo valve 19 is controlled so that the flow rate Q _S is obtained in order to lower the slide 11. At the same time, the set pressure P2 of the pressure control valve 17 is controlled to become Pset. Therefore, the slide 11 begins to descend as shown by the arrow A (Fig. 1). As the slide 11 descends, the output P1 of the pressure sensor 18 gradually increases, and at time t ₁ ′ when the upper die 6 and the lower die 4 come into contact, the output P1 of the pressure sensor 18 changes to the pressure control valve.
The pressure Pset limited at 17 is reached. At this time t ₁ ′, the deformed state of the slide 11 and the bolster 5 is the same as that shown in FIG. 4, and the same bending as the bending W occurs.

Next, the pressure valve control unit 23 sets the set pressure P2 of the pressure control valve 17 at the time point t ₁ ′ when the output Pset is input from the pressure sensor 18.
Is controlled to be zero (see arrow B).

Therefore, the load on the hydraulic cylinder 7 is removed, and the output P1 of the pressure sensor 18 gradually decreases. Eventually, at time t ₁ , the output P1 of the pressure sensor 18 becomes zero, and the hydraulic cylinder 7
Load F becomes zero. At this time point t ₁ , as shown in FIG. 3, the slide 11 and the bolster 5 are in a state where mechanical deformation due to the load F has not occurred.

Thus, the pressure valve control unit 23 outputs a clear signal CL to the counter 25 in the time t _1, the counter 25 is said time point t ₁
The detection position Sr of the encoder 12 in is set to zero, that is, the movement position of the slide 11 is set and stored (see arrow C).

Conventionally, when the deflection W is generated on the slide 11
The output S'of the encoder 12 at t ₁ 'is set to zero, but in this embodiment, the error due to the deflection W is caused.
WD is removed and the true origin position Sr is obtained.

Therefore, if the detection position Sr of the encoder 12 thus obtained is set as the origin, that is, the mold contact position, and the process proceeds to the mold clamping step, accurate work can be performed.

In addition, although the slide 11 is described as being driven by hydraulic pressure in the embodiment, of course, it may be driven by pneumatic pressure or the like.

Further, the actuator that drives the slide 11 may have the same function as the hydraulic cylinder 7 of the embodiment. Similarly, the sensor that detects the moving position of the slide 11 is
The function may be the same as that of the incremental encoder 12 of the embodiment.

Further, in the embodiment, the pressure sensor 18 is arranged between the pressure control valve 17 and the servo valves 19 to 22 to detect the hydraulic pressure of the hydraulic circuit 2, but the point is to detect the load of the hydraulic cylinder 7. As long as the sensor can be used, the type of sensor and the location of the sensor are arbitrary.

[Effect of device]

As described above, according to the present invention, since the die contact position of the press machine is accurately positioned, the press working can be accurately performed.

[Brief description of drawings]

FIG. 1 is a block diagram conceptually showing the structure of an embodiment of a die contact position positioning device of a press machine according to the present invention, and FIG. 2 explains the operation of the sequence control circuit shown in FIG. A time chart used for this purpose, FIG. 3 is a front view conceptually showing the mechanically deformed state of the hydraulic press shown in FIG. 1 at the time when positioning is performed in the embodiment, and FIG. FIG. 3 is a front view conceptually showing a mechanically deformed state of the hydraulic press at the time when is performed. 1 ... hydraulic press, 4 ... lower mold, 5 ... bolster, 6 ...
… Upper mold, 7-10 …… hydraulic cylinder, 11 …… slide, 12
〜15 …… Incremental encoder, 16 …… Hydraulic pump, 17 …… Pressure control valve, 18 …… Pressure sensor, 19〜22 ……
Servo valve, 23 ... Pressure valve control unit, 24 ... Servo valve control unit, 25 ... Counter.

Claims (1)

[Scope of utility model registration request] 1. A press machine comprising a bolster supporting a lower die, a slide for supporting an upper die to move up and down, and an actuator for driving the slide, and load detecting means for detecting a load of the actuator. A position detecting means for detecting a moving position of the slide; a control means for making the driving force of the actuator zero when the detected load of the load detecting means becomes a predetermined value or more; When the detected load of the load detection means becomes zero after the driving force is made zero, the detection position of the position detection means at this time is set as the contact position of the upper die and the lower die. A die contact position positioning device for a press machine that performs press working based on a set contact position.