JP2924562B2 - Press machine load setting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load setting method for a press machine, and more particularly to a load setting method for independently controlling a plurality of press loads so that a predetermined load distribution is obtained.

[0002]

2. Description of the Related Art A press machine that performs press working by vertically moving a press slide on which a press upper die is attached,
This type of press machine is often used for press working of automobile bodies, etc., and a strain sensor is attached to a frame that supports the press slide or an up-down drive member that moves the press slide up and down. There is an apparatus which can detect a press load by detecting the pressure. JP 5
An apparatus described in Japanese Patent Application Laid-Open No. 7-30919 and an apparatus described in Japanese Patent Application No. 4-322405 filed by the applicant of the present invention are examples of such a technique. A permanent magnet and a Hall element are used as a strain sensor. And a dial gauge type, a capacitance type, a strain gauge type, an optical type, a differential transformer type, a rotary encoder type, and the like. In a press machine capable of measuring a press load in this way, the target press load is adjusted by adjusting the relative distance (for example, h _{1 in} FIG. 2) between the press slide and the vertical driving member by a die height adjustment mechanism or the like. Load control can be performed so as to obtain, for example, an optimum press load obtained by a tri-press at the time of die production can be quickly reproduced by a press machine in a production line.

[0003]

However, due to the play of the drive mechanism for moving the press slide up and down, backlash of gears, variations in parallelism and dimensional errors of the press slide, and variations in rigidity of various parts of the press machine, etc. Since the load change characteristics are different from each other, even if the entire press load can be reproduced, the load distribution differs for each press machine, and a desired press quality may not be obtained. In this case, it is possible to repair the press machine so as to obtain the desired press quality according to the press die to be used, but when processing a plurality of types of press products while replacing a plurality of press dies. In order to affect other press quality, press dies are modified according to the habit of the press machine.

The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to easily obtain a desired press load distribution irrespective of individual differences between press machines.

[0005]

To achieve SUMMARY OF THE INVENTION The above objects may be so adjustable independently a press load of a plurality of locations of the press machine, the present invention is, hydraulic oil
Are connected to a vertical driving member via a plurality of hydraulic cylinders confined in a substantially constant space, and are moved up and down substantially integrally with the vertical driving member, and are used for press working.
That multiple hydraulic cylinders are driven
A press slide for transmitting a press load to a plurality of positions via the plurality of hydraulic cylinders , and a press machine for performing press working by vertically moving an upper press die attached to the press slide. hand,
(A) a load detecting step of detecting a press load of a plurality of locations corresponding to said plurality of hydraulic cylinders, (b) a non-press-
Independent hydraulic pressure in the hydraulic cylinders during construction
And adjust the load to the amount of the press slide
A fluid pressure adjusting step of changing the change characteristics so that the press load at the plurality of locations substantially matches a predetermined set press load.

[0006]

[Effect of the action and the Invention That is, if such pressing force to press the slide via the hydraulic cylinder is transmitted, by adjusting the hydraulic pressure of the hydraulic cylinder,
Since the load change characteristic with respect to the amount of press-slide can be changed, the hydraulic cylinders are arranged at a plurality of positions on the press slide, and the hydraulic cylinder
By independently adjusting the hydraulic pressures of the dies , the press load at a plurality of positions on the press slide can be set independently, and the load distribution can be changed. Therefore, the press load at a plurality of locations corresponding to the plurality of hydraulic cylinders is detected, and the hydraulic pressure in the plurality of hydraulic cylinders during non-press working is detected.
Are adjusted independently to adjust the amount of press slide
By changing the load change characteristics for
Press load approximately matches the preset press load
By doing so, a desired press load distribution can be easily reproduced regardless of the individual difference of the press machine, and a good press product can always be obtained. In addition, since the desired press load distribution is easily reproduced in this manner, the time required for load adjustment and mold repair at the time of mold replacement is reduced, the burden on the operator is reduced, and the operation of the press machine is reduced. The rate is improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an overall configuration diagram of a single-action type press machine 10 that performs a drawing process. A drive mechanism 16 that drives a press slide 14 up and down is supported by four frames 12 provided at four corners. The drive mechanism 16 includes an electric motor, a gear, a link, a crankshaft, and the like. The drive mechanism 16 includes four plungers 18 disposed inside the frame 12 and each having a lower end connected to the press slide 14. Up and down drive is performed in synchronization. A die 20 is attached to the lower surface of the press slide 14, while a punch 26 is attached to the press bed 22 via a bolster 24. The work 28 is subjected to drawing by the die 20 and the punch 26. In punch type 26,
A wrinkle holding ring 30 is provided so as to be vertically movable relative to each other, and the wrinkle holding ring 30 is provided with a large number of cushions which can be pushed downward against the urging force of an air cylinder (not shown). It is supported on a pin 32, and presses the peripheral portion of the work 28 between the die die 20 during the drawing. The plunger 18 corresponds to a vertical drive member, and the die 20 corresponds to an upper press die.

The four plungers 18 are connected to the front left and right sides and the rear left and right sides of the substantially rectangular press slide 14 via die height adjusting mechanisms 34 shown in FIG. 2, respectively. The die height adjusting mechanism 34 is provided on a screw shaft 36 provided integrally with the plunger 18, and a nut member 38 screwed to the screw shaft 36.
And a worm wheel 40 fixed to the nut member 38 and a worm 42 screwed to the worm wheel 40. 4 die height adjustment mechanisms 3
The worm 42 of No. 4 is rotationally driven in both the forward and reverse directions by a common servo motor 43 (see FIG. 3).
8 is rotated to the forward and reverse directions, the height position of the die-height adjusting mechanism 34 relative to the screw shaft 36, i.e. the relative distance h ₁ of the press slide 14 against the plunger 18 is adjusted uniformly. The press slide 14 is lowered with respect to the plunger 18 as the relative distance h ₁ increases,
The pressing force when the plunger 18 reaches the lower end, that is, the press load Fp is changed.

The die height adjusting mechanism 34 includes a piston 4 of a hydraulic cylinder 44 provided to prevent overload.
6, while the housing of the hydraulic cylinder 44 is integrally disposed on the press slide 14. The pressure chamber of the hydraulic cylinder 44 is filled with hydraulic oil and communicates with an oil chamber 52 of the cylinder 50 via an oil passage 48. In the oil passage 48, hydraulic oil pumped from a tank 56 by an electric pump 54 is supplied with a check valve 58 and an electromagnetic ON / OFF oil supply / discharge valve 60.
And the oil pressure P in the oil passage 48
a is detected by a hydraulic pressure sensor 62, and the hydraulic pressures Pa of the four hydraulic cylinders 44 are independently controlled. ON / OFF oil supply / discharge valve 60
Can be switched in accordance with an electric signal between a shut-off state in which the electric pump 54 and the oil passage 48 are shut off, an oil supply state in which the electric pump 54 and the oil passage 48 are communicated, and a drainage state in which the oil passage 48 is communicated with the drain oil passage 64. Has become. The hydraulic oil is supplied to the four hydraulic cylinders 44 from a common electric pump 54.

The cylinder 50 has an air chamber 68 opposite to the oil chamber 52 with a piston 66 interposed therebetween. The air chamber 68 is communicated with an air tank 70 and the air tank 70 is an electromagnetic type. It is connected to a pressure air source 74 via an ON / OFF supply / exhaust valve 72,
The air pressure Pc in the air chamber 68 and the air tank 70 is adjusted by switching the ON / OFF supply / exhaust valve 72. The ON / OFF supply / exhaust valve 72 has the same function as the ON / OFF supply / exhaust valve 60, and the air pressure Pc is detected by the air pressure sensor 7.
6 detected. When an excessive load acts on the hydraulic cylinder 44, the air pressure Pc
6 according to the press capacity of the press machine 10 so as to allow the die height adjusting mechanism 34 and the press slide 14 to approach each other by retracting to the air chamber 68 side and to prevent damage to the press machine 10 and the mold. Is regulated. This cylinder 5
0, the air tank 70, etc. are also provided at the connecting portions between the four plungers 18 and the press slide 14, respectively.
The air pressure Pc is applied to the four hydraulic cylinders 44 and 50
The pressure is separately adjusted in accordance with the variation in the pressure receiving area. The piston 66 may be urged by a compression coil spring or the like instead of the cylinder 50.

The press slide 14 is also connected to pistons of four balancer air cylinders 80 provided in a housing 78 of the drive mechanism 16. The air chamber 82 of the air cylinder 80 communicates with an air tank 84, and the air tank 84 is turned on and off by an electromagnetic type.
The pressure air source 74 is connected to the pressure air source 74 via an OFF air supply / exhaust valve 86.
The internal air pressure Pb is adjusted. ON,
The OFF supply / exhaust valve 86 has the same function as the ON / OFF supply / exhaust oil valve 60 and has the air pressure Pb.
Is detected by an air pressure sensor 88, and the air pressure Pb is adjusted so as to balance the weight of the press slide 14 and the die 20. The air chambers 82 of the four air cylinders 80 are connected to a common air tank 84.

On the other hand, a strain gauge 90 is attached to each of the four frames 12 as a strain sensor, and outputs a strain signal Sε corresponding to the elongation strain of each frame 12. These strain gauges 90 are connected to one frame 12.
Are connected to each other so as to form a bridge circuit.

The press machine 10 includes a controller 92 as shown in FIG. 3, and includes the hydraulic sensor 62, the air pressure sensors 76 and 88, and the servomotor 43.
The attached rotary encoder 94, the hydraulic pressure Pa is outputted from the strain gauge 90, signal and the distortion signal Sε indicating air pressure Pc, Pb, the relative distance h _1, is supplied to the controller 92. Also, the stroke sensor 96
Supplies a signal representing the press stroke Sp of the press machine 10. The stroke sensor 96 includes, for example, an encoder that detects a rotation angle of a crankshaft of the drive mechanism 16. The controller 92 is a CPU 9
8, RAM 100, ROM 102, machine information memory 1
04, a mold information memory 106, a microcomputer having an input / output interface circuit (not shown), an A / D converter, and the like. Signal processing is performed in accordance with a program stored in the ROM 102 in advance while utilizing the temporary storage function of the RAM 100. And outputs drive signals for switching the ON / OFF oil supply / discharge valve 60, ON / OFF oil supply / exhaust valves 72 and 86, and changing the operation state of the electric pump 54 and the servomotor 43.

The machine information memory 104 stores in advance machine information unique to the press machine 10 such as the weight Ws of the press slide 14, the pressure receiving area Ab of the air cylinder 80, the overload prevention air pressure Pco, Load-strain characteristics and the like representing the relationship between the signal Sε and the load are stored. The pressure receiving area Ab is a total of the four air cylinders 80, and is determined in advance by calculating load-air pressure characteristics by experiments or simulations in consideration of air leakage, sliding resistance, and the like. The overload prevention air pressure Pco is a set value of the air pressure Pc of the cylinder 50, and takes into account the pressure receiving area of the hydraulic cylinder 44 and the cylinder 50, the sliding resistance, and the like, so that the piston 66 retreats at a predetermined overload prevention load. In addition, four air pressures Pc are respectively determined in advance by experiments and the like. The load-strain characteristic representing the relationship between the strain signal Sε and the load is represented by the correspondence between the strain signal Sε and the press load Fp as shown in FIG. Each of the strain gauges 90 is defined.

As shown in FIG. 5, for example, four load measuring tables 108 are mounted on the bolster 24 instead of the die 20 and the punch 26 as shown in FIG.
It is created by measuring the actual press load Fp while detecting the elongation strain of the frame 12 by the strain gauge 90. The load measuring table 108 is disposed directly below the plunger 18 and has a strain gauge 110 attached thereto. The strain gauges 110 are connected to an electromagnetic oscilloscope 114 via a dynamic strain gauge 112. . Four strain gauges 110 are attached to one load measuring table 108, and are connected so as to form a bridge circuit. The dynamic strain meter 112 has an amplifying function, a zero-point adjusting function, and the like, and the electromagnetic oscilloscope 114 records a load change accompanying the descending and rising of the press slide 14 with high followability. The die height adjustment mechanism 34
The press machine 10 is operated while adjusting the height of the press slide 14 to change the press-in amount by pressing, and the maximum value of the press load Fp recorded on the electromagnetic oscilloscope 114 and the strain gauge attached to the frame 12. 9
FIG. 6 plots the maximum value of the strain signal Sε of 0, and FIG. 4 shows the correspondence between the press load Fp and the strain signal Sε based on the data of FIG. As a result, a total of four press loads Fp on the front left and right sides and the rear left and right sides corresponding to the plungers 18 are applied to the strain signals Sε of the strain gauges 90 attached to the four frames 12.
, Each is detected with high accuracy. The press load of the entire press machine 10 is a total press load Fpt, which is the sum of the four press loads Fp. In addition, the load measuring table 108 is composed of two types of blocks prepared from a plurality of types of blocks prepared in advance and having different heights, so that the height of the two types of blocks is approximately equal to the height of the die 20 and the punch 26. Are selected and combined.

Referring back to FIG. 3, the mold information memory 106 stores the mold-specific mold information read from the ID card 118 (see FIG. 1) attached to the punch mold 26 by the transceiver 116, that is, good mold information. The forming load Ffo, the weight Wu of the upper die (the die 20), the thickness t of the pressed material, and the like that can process a pressed product are stored. ID card 118
Is provided with a storage function for storing mold information, a transmission / reception function, a battery, and the like, and transmits mold information by receiving a data fetch signal from the transceiver 116. The above-mentioned forming load Ffo is tested in a tri-press configured in the same manner as the press machine 10 in FIG. 1 while detecting the pressing load Fp with the strain gauge 90, and under the conditions of the forming load at which a good pressed product is obtained. Yes, it is defined for each of the four locations, front, rear, left, and right. The press load Fp detected by the strain gauge 90 changes in one stroke of the press machine 10 as shown in FIG. 7, and the wrinkle holding load Fs and the forming load Ff are respectively obtained from the waveforms. The forming load Ff when it is obtained is set as the forming load Ffo. The forming load Ff is the die 1
0 and the punching type 26, and the wrinkle holding load Fs is a load applied to the wrinkle holding ring 30 by the air cylinder via the cushion pin 32, and is used as the die type 20 and the wrinkle holding ring 30. And the pinching load between them.

[0017] The said controller 92, is connected to the display and operation panel 190 shown in FIGS. 8 to 10, wherein the switch operation of the operator relative distance h ₁ or 4 places pressure P
a is adjusted. These adjustments are performed, for example, according to the flowcharts of FIGS. This flowchart shows the operation by the operator together with the operation by the controller 92.

In step Q1 of FIG.
By operating a switch provided on the operation panel of the mold 0, the mold (2
The bolster 24 on which (0, 26, 30) is placed is moved into the press machine 10, and the bolster 24 is automatically positioned at a predetermined position in step Q2. Thereafter, in step Q3, when the operator operates the changeover switch 192 of the display operation panel 190 to the "individual" mode, and in step Q4, the operator operates the changeover switch 194 to the "setup" mode, the setup lamp 196 is turned on. I do. After the operator presses the operation preparation push button 198 in step Q5, when the operator turns on the test hitting switch of the press machine 10 in step Q6, the press machine 10 is operated by jolting or the like. At this time, the air pressure Pb of the air cylinder 80 is set in advance so that Pb ≒ Ws / Ab based on the weight Ws of the press slide 14 and the pressure receiving area Ab of the air cylinder 80 stored in the machine information memory 104. The air pressure Pc of each of the four cylinders 50 is adjusted in advance so as to substantially match the overload prevention air pressure Pco also stored in the machine information memory 104. The adjustment of the air pressures Pb and Pc may be performed by an operator switching a manual valve or the like while watching the air pressure meter.

In the next step Q7, the strain signals S of the four strain gauges 90 are generated in the process of lowering the press slide 14.
It is determined whether or not the total press load Fpt obtained based on ε has reached a predetermined set load F ₀ , and Fpt
= When becomes F _0, the descent of the press slide 14 is stopped at step Q8. The set load F ₀ is set in advance to a value of, for example, about several tons to several tens tons so as not to overload the electric motor or the like of the press machine 10.
Further, lowering of the press slide 14 in Fpt = F ₀ is given to the automatic stop is to "setup" mode is selected. In a succeeding step Q9, the die 20 is fixed to the press slide 14. The mounting of this die 20
It is automatically performed by a die clamper or the like, but may be manually performed by an operator using a T-bolt or the like.
In step Q10, the press stroke Sp at the time of the stop is stored as the stroke Sp1, and in step Q11, the reverse operation of the press switch 10 of the press machine 10 causes the press slide 14 to rise in the reverse direction. In step Q12, the stroke sensor 96
It is detected that the press slide 14 has reached the top dead center by, for example, and the top dead center lamp 200 is turned on.
The operator stops the press machine 10.

Next, in step Q13, when the operator operates the changeover switch 194 to the "try" mode, the try lamp 202 is turned on. At step Q14, along with determining the distance whose ASP to bottom dead center from the set load F ₀ generation, that is, when the stop position when the mold mounting on the basis of the stroke Sp1, that distance whose ASP, die data memory 10
6 the thickness of the press material stored in t, the additional thrust amount x ₀ predetermined, the amount of change Δh relative distance h ₁ is calculated according to the following equation (1), the drives the servo motor 43 changing the relative distance h ₁ by changing the amount Delta] h. By reducing the distance to the bottom dead center by ΔSp, the total press load Fpt = F ₀ when the press slide 14 is lowered to the bottom dead center. By further reducing the plate thickness t, the press material was introduced. the total pressing load Fpt = F ₀ at the bottom dead center of the case. That is, by changing the relative distance h ₁ by changing the amount Delta] h, the press thrust amount when lowering the press slide 14 to the bottom dead center by introducing the press material, since increased by substantially adding thrust amount x ₀ is there. Additional thrust amount x _0, for example 1.
A value of about 0 mm is set.

Δh = −ΔSp−t + x ₀ (1)

Here, the mold information such as the plate thickness t is obtained by operating the ID communication switch 204 of the display / operation panel 190 to the "ON" side after the step Q2 and reading the push button 20.
6 is pressed from the ID card 118, read from the ID card 118, stored in the mold information memory 106, and displayed on the display unit 208 of the display / operation panel 190. The display unit 208 is provided with a display 210 for displaying the total forming load Ffot, which is the sum of the forming loads Ffo, and a display 216 for displaying the weight Wu of the upper die (the die 20).

In step Q15, a press material is charged,
In step Q16, the operator turns on the test hitting switch to operate the press machine 10 for one cycle. At this time, the air pressure Pb of the air cylinder 80 depends on the weight Ws of the press slide 14 and the pressure receiving area Ab of the air cylinder 80 stored in the machine information memory 104, and the die type stored in the die information memory 106. Based on the weight Wu of 20, the pressure is adjusted so that Pb ≒ (Ws + Wu) / Ab. In step Q17, the total press load Fpt at the bottom dead center during the press operation detected on the basis of the distorted signal Sε strain gauges 90, to the total press load Fpt and F _1. And step Q
At 18, the load values F ₀ , F ₁ and the additional addition amount x ₀
Then, the load change ratio Δa is calculated according to the following equation (2).
FIG. 13 is a graph showing the relationship between the load values F ₀ and F ₁ and the amount of press-in. The load change ratio Δa corresponds to the slope of this graph, which is a characteristic unique to the press machine 10. The press-in amount is the relative distance h when the die 20 just abuts the punch 26 at the bottom dead center of the press.
₁ is a reference value h ₀ , which is an increase amount (h ₁ −h ₀ ) of the relative distance h ₁ from the reference value h ₀ , and each part of the press machine 10 elastically deforms as the press-in amount increases. Or the hydraulic oil in the hydraulic cylinder 44 is compressed and deformed, and a press load Fp is generated.

Δa = (F ₁ −F ₀ ) / x ₀ (2)

[0023] Then at step Q19 of FIG. 12 to be executed, the load change rate .DELTA.a, the sum of the forming load Ffo stored in the die data memory 106 total forming load Ffot, on the basis of the load value F ₁ , the change amount x ₁ relative distance h ₁ as well as calculated according to the following equation (3), by driving the servo motor 43 to change the relative distance h ₁ by the change amount x _1. As described above, the relative distance h ₁ is the change amount x ₁
13, the total press load Fpt at the bottom dead center is basically the total forming load Ffot. Note that, at this stage, the air cylinder for wrinkle holding, which urges the wrinkle holding ring 30 via the cushion pin 32, is locked at the lower end, and even when the press slide 14 is lowered to the bottom dead center. The die 20 does not contact the wrinkle holding ring 30 and the wrinkle holding load is zero. Also, by substituting the load change ratio Δa of the above equation (2) into the equation (3), the load values F ₀ and F ₁ , the total forming load Ffot,
It is also possible to calculate the change amount x ₁ directly from the additional thrust quantity x _0.

X ₁ = (Ffot−F ₁ ) / Δa (3)

In step Q20, the operator turns on the test hitting switch to operate the press machine 10 for one cycle. In step Q21, the total press load Fpt at the bottom dead center during the press operation is measured by the strain gauge 90. The signal is detected based on the signal Sε, and the difference between the total press load Fpt and the total forming load Ffot | Fpt−Ffo
It is determined whether or not t | is smaller than a predetermined error allowable range α. The error allowable range α is, for example, 1.0 when the total forming load Ffot is 80 kN (kilonewton).
It is set to about kN. And | Fpt−Ffot | ≧ α
In the case of, | Fpt-Ffot | <changing the relative distance h ₁ at step Q22 until the alpha. The change of the relative distance h ₁ may be automatically performed by linearly approximating the load change with respect to the press-in amount, similarly to the steps Q18 and Q19, but is displayed on the display 218 of the display / operation panel 190. The operator looks at the value of the actual total press load Fpt, and sees the total forming load F displayed on the display 210.
As compared with fot, the servo motor 43 of the press machine 10 may be operated by a switch operation.

When the determination in step Q21 is YES, the total load lamp 220 of the display / operation panel 190 is turned on, and subsequently, step Q23 and subsequent steps are executed. Steps Q23 to Q25 are for adjusting the load distribution of the molding load. More specifically, the press loads Fp at the four locations are stored in the mold information memory 106, respectively.
The hydraulic pressures Pa of the four hydraulic cylinders 44 are independently adjusted so as to substantially coincide with fo. That is, the backlash of the drive mechanism 16 and the backlash of the gear, the press slide 1
4 of parallelism of variation, dimensional error, due to variations in the stiffness of the press machine 10 each part, differs each load change characteristics of each section of the press machine 10, the relative distances h ₁ total forming load Total press load Fpt by adjusting F
Even if it is substantially equal to fot, the load distribution differs for each press machine 10, and the desired press quality cannot be ensured. For example,
When the parallelism of the press slide 14 is poor, the load change characteristics at four points measured by the strain gauge 90 are as shown in FIG.
Look like, this characteristic can not be changed in the adjustment of the relative distance h ₁ by a single servo motor 43. On the other hand, when the load change characteristic indicated by the solid line in FIG. 15 is obtained, when the hydraulic pressure Pa of the hydraulic cylinder 44 during the non-press working is increased, the load change characteristic becomes steeper as shown by the one-dot chain line, When the oil pressure Pa is lowered, the load change characteristic becomes gentler as shown by the two-dot chain line. Therefore, the hydraulic pressure Pa of the four hydraulic cylinders 44
Are independently adjusted by switching the ON / OFF oil supply / drainage valve 60, so that four press loads F
It is possible to change p independently of each other so as to substantially match the forming load Ffo.

In the first step Q23, it is determined whether or not the four press loads Fp at the bottom dead center detected by the strain gauge 90 at the time of the press operation in the step Q20 substantially coincide with the forming load Ffo, in other words, whether the press is performed. Load F
It is determined whether or not the difference | Fp−Ffo | between p and the forming load Ffo is smaller than a predetermined error allowable range β for each of the four positions. If all of them are within the error allowable range β, a series of adjustment processing is performed. The process is ended, but if at least one position exceeds the error allowable range β, the step Q24 is executed. Among the four locations, those within the error tolerance range β are indicated on the display / operation panel 1
At 90, the corresponding one of the load distribution lamps 222 provided separately for "right front", "right rear", "left front", and "left rear" is turned on. For example, the error allowable range β is set to 0.3 kN, the right front forming load FRFfo = 20 kN, the right rear forming load FRRfo = 16 kN, the left front forming load FLFfo = 23 kN.
N, with the left rear forming load FLRfo = 21 kN, the detected right front press load FRFp = 25.0 kN, the right rear press load FRRp = 12.0 kN, and the right front press load FLFp = 2
In the case of 2.9 kN and the right front press load FLRp = 21.1 kN, | Fp−Ffo | <
β, among the load distribution lamps 222, the "left front" and "left rear" lamps are turned on.

In step Q24, step Q23
, The hydraulic pressure Pa of the hydraulic cylinder 44 of the corresponding portion is changed for the portion determined as | Fp−Ffo | ≧ β, in the above example, “front right” and “right rear”. The switch is turned on to operate the press machine 10 for one cycle. Based on the strain signal Sε output from the strain gauge 90 at the time of the press operation, four press loads Fp at the bottom dead center of the press are detected, and thereafter, the process returns to step Q23 to determine the four load again.
The hydraulic pressure Pa is basically changed by increasing the hydraulic pressure Pa when Fp-Ffo <0, and by increasing the hydraulic pressure Pa when Fp-Ffo> 0.
a may be reduced, but the change width may be set to a fixed value in advance, or may be set according to the load difference | Fp-Ffo | or the like. Also, the molds 20, 26, 30
The load measuring table 108 and the like are arranged in place of
The change characteristics of the press load Fp with respect to a are obtained in advance and stored as machine information in the machine information memory 104, and the load change characteristics are determined by the actual stiffness of the dies 20, 26, and 30 by trial hitting or the like. , The hydraulic pressure Pa at which the forming load Ffo can be obtained can be relatively easily obtained. If the four press loads Fp and the forming load Ffo are respectively displayed on a display or the like, and the four ON / OFF oil supply / drain valves 60 can be switched by operating the switches, the work on the display can be performed. The operator can adjust the hydraulic pressure Pa manually. Further, when Fp-Ffo> 0, the press machine 10 is held at the bottom dead center and the hydraulic oil in the hydraulic cylinder 44 is automatically or manually discharged until Fp ≒ Ffo.
The adjustment of the hydraulic pressure Pa can be performed by various methods.

As described above, the press machine 10 of this embodiment
The strain gauge 90 detects four press loads Fp corresponding to the four hydraulic cylinders 44, and sets the four hydraulic pressures so that each of the press loads Fp substantially matches a predetermined forming load Ffo. Since the hydraulic pressure Pa in the cylinder 44 is adjusted independently,
Regardless of the individual difference of the press machine 10, almost the same molding load distribution as in the case of the tri-press is quickly reproduced, and a good press product can always be obtained. Further, since the desired press load distribution is easily reproduced in this manner, the time required for the load adjustment and the die repair at the time of die replacement is reduced, the burden on the operator is reduced, and the press machine 10 The operation rate improves.

In this embodiment, the portion for detecting the press load Fp at the time of the press operation in step Q25 is a load detection step, and steps Q23 and Q24 are fluid pressure adjustment steps. The hydraulic cylinder 44 corresponds to the hydraulic cylinder described in claim 1, and the forming load Ffo stored in the ID card 118 in advance corresponds to the set press load.

In the above example, step Q7 in FIG.
In total pressing load Fpt it is determined whether to match the set load F _0, it was supposed to stop the descent of the press machine 10 at Fpt = F _0, step Q7 as shown in FIG. 16 Is omitted, and the press slide 14 is a die mold 2
The operator may visually confirm that the press machine 10 has come into contact with 0, and stop the lowering of the press machine 10 by operating a switch. In that case, at step Q10, stores the press stroke Sp during descent stops as stroke Sp1, a total pressing load Fpt stored as a load F _0, thereafter using the stroke Sp1, load value F ₀ for it, such as May be performed.

Further, although the above embodiment has been previously fixed value is defined as an additional thrust amount x _0, the mold 20 and 26,
Instead of 30, a more rigid load measuring table 108
Or the like is arranged, by measuring a total pressing load Fpt while changing the relative distance h _1, for example, FIG. 17 is obtained in advance a provisional load change characteristic A as shown by the solid line in, this as machine information by storing the machine data memory 104, it is possible to increase the additional thrust amount x ₀ in a range that does not overload the press machine 10. That is,
On the basis of the load value F ₀ , if the load change characteristic is A, the additional addition amount at which the total forming load Ffot can be obtained is x
Determined as _0, it is to calculate the change amount Δh in accordance with the (1) equation by using the additional thrust quantity x _0. FIG.
7B is an actual load change characteristic, which corresponds to the load change characteristic in FIG. 13, but the temporary load change characteristic A is obtained by interposing a member having higher rigidity than the mold, The actual load change characteristic B has a gentler slope than the temporary load change characteristic A, and even if the press additional amount is changed by the additional additional amount x ₀ obtained based on the temporary load change characteristic A, the press machine No heavy load is applied. Further, since the sought purpose and load change characteristics using a load value F ₁ close to the total forming load Ffot to B, and a load change rate Δa other words, fewer errors, compared to a load variation characteristic of FIG. 13, the or modifications relative distance h ₁ becomes unnecessary at step Q22, the number of corrections or reduced. In addition,
Any additional thrust amount if the load change characteristic A is the total molding load Ffot obtained had a x _0, it is not necessary to set additional thrust quantity x ₀ on the basis of the total forming load Ffot, a smaller load than in may of course also possible to set additional thrust quantity x ₀ on the basis of slightly larger load than the total forming load Ffot.

In the above embodiment, the single-action press machine 10 has been described.
The present invention can be applied to a double action type press machine 150 as shown in FIG. In FIG. 18, the die 1
52 is used fixedly on the bolster 154,
The wrinkle holding ring 156 is a blank holder plate 158.
Is fixed to the outer slide 160 through the
Reference numeral 62 is used by being fixed to the inner slide 164.
The outer slide 160 has four outer plungers 166.
It can be moved up and down via
The inner slide 164 has four inner plungers 168.
And presses the peripheral edge of the press material between the wrinkle holding ring 156 and the wrinkle holding portion 153 of the die 152 while pressing the punch die 162.
The drawing process is performed by using the die 152. The outer slide 160 and the inner slide 164 correspond to a press slide, the outer plunger 166 and the inner plunger 168 correspond to a vertical driving member, and the wrinkle holding ring 156 and the punch mold 162 correspond to an upper press mold.

As is clear from FIG. 19, strain gauges 230 are attached to the four outer plungers 166, respectively. Based on the strain of each outer plunger 166, the press load Fp is determined in the same manner as in the previous embodiment. In such a case, a wrinkle holding load is detected, and the outer plungers 166 are connected to the outer slide 160 via a die height adjusting mechanism 234, respectively. The die height adjustment mechanism 234 includes the screw shaft 2
36, the nut member 238, the worm wheel 240, and includes a worm 242, the relative distance h ₂ is uniform by warm 242 of die-height adjusting mechanism 234 at four positions are rotated forward and reverse directions by a common servo motor And the press load Fp when the outer plunger 166 reaches the lower end is changed.

The die height adjusting mechanism 234 is integrally connected to a piston 246 of a hydraulic cylinder 244 provided for adjusting a wrinkle holding load, while a housing of the hydraulic cylinder 244 is integrally provided on the outer slide 160. Have been. The pressure chamber of the hydraulic cylinder 244 is filled with hydraulic oil and communicated with the oil chamber 252 of the cylinder 250 via an oil passage 248. The hydraulic oil pumped from the tank 256 by the electric pump 254 is supplied to the oil passage 248 with a check valve 258 and an electromagnetic O
The oil pressure Pd is supplied through an oil supply / discharge valve 260 and an oil pressure Pd in the oil passage 248.
The hydraulic pressures Pd of the four hydraulic cylinders 244 are independently controlled.

The cylinder 250 has an air chamber 268 opposite to the oil chamber 252 with the piston 266 interposed therebetween. The air chamber 268 is connected to an air tank 270, and the air tank 270 is an electromagnetic type. O
N, OFF pressure air source 27 via supply / exhaust valve 272
4, ON / OFF supply / exhaust valve 272
Is switched, the air pressure Pf in the air chamber 268 and the air tank 270 is adjusted. This air pressure Pf is detected by the air pressure sensor 276. The cylinder 250, the air tank 270, etc.
Four outer plungers 166 and outer slide 160
The air pressures Pf at four locations are independently adjusted.

The outer slide 160 is connected to pistons of four balancer air cylinders 280. The air chambers 282 of the air cylinders 280 are connected to an air tank 284, and the air tank 284 is an electromagnetic type. Are connected to the pressure air source 274 via ON / OFF supply / exhaust valves 286 of
By controlling the switching of the OFF supply / exhaust valve 286, the air pressure Pe in the air chamber 282 and the air tank 284 is controlled.
Is to be adjusted. The air pressure Pe is detected by an air pressure sensor 288, and the air pressure Pe is adjusted so as to balance the weight of the outer slide 160, the blank holder plate 158, and the wrinkle holding ring 156. In addition, four air cylinders 2
The 80 air chambers 282 are connected to a common air tank 284.

In the press machine 150, four wrinkle pressing loads Fso corresponding to the outer plunger 166 are respectively set independently by an ID card or the like, and are first detected by the strain gauge 230. that is the sum of the pressing load Fp total pressing load Fpt may wrinkles by adjusting the relative distance h ₂ so that the total blank-holding force Fsot is the sum of the holding force Fso, then wrinkles four positions pressing load Fp, respectively The hydraulic pressure Pd or the air pressure Pf is adjusted so as to obtain the pressing load Fso. The load change characteristics of the total press load Fpt with respect to the press-in amount are refracted by the load Fct as shown in FIG. 20, and the portions below the load Fct are elastically deformed or actuated in the hydraulic cylinder 244 as in the previous embodiment. It is based on the compressive deformation of oil.
The bending point load Fct is determined by the air pressure Pf and the pressure receiving area on the air chamber 268 side. Therefore, four cylinders 25
If the total value of the pressure receiving areas on the air chamber 268 side at 0 is stored in advance as machine information, the bending point load Fct is obtained based on the initial set air pressure Pf when performing the load adjustment, as shown in FIG. by the load slightly greater than the refraction point load Fct a set load F _0, it is possible to adjust the relative distance h ₂ so that Fpt ≒ Fsot in the same manner as in example. (A) of FIG. 21, FIG if the previously constant value is defined as an additional thrust amount x ₀ 1
Corresponding to 3, corresponding to FIG. 17 in the case where additional thrust amount x ₀ is set from (b) in advance temporary load change characteristic A which is stored as the machine information.

On the other hand, the load change characteristics of the four press loads Fp detected by the strain gauge 230 with respect to the press-in amount are the same as those in FIG. 20. For example, the load change characteristics shown by the solid line in FIG. In this case, when the hydraulic pressure Pd of the hydraulic cylinder 244 is increased, the load change characteristic has a steep slope at a portion below the bending point load Fc as indicated by a dashed line, and when the hydraulic pressure Pd is decreased,
As shown by the two-dot chain line, the slope of the load change characteristic becomes gentle at a portion below the bending point load Fc. Therefore, FIG.
Similarly to Steps Q23 to Q25 of Step 2, four press loads Fp corresponding to the four hydraulic cylinders 244 are detected by the strain gauge 230, and the press loads Fp substantially coincide with the predetermined wrinkle holding loads Fso, respectively. So that the hydraulic pressures Pd in the four hydraulic cylinders 244 are set to O
If the N and OFF oil supply / drain valves 260 are adjusted independently by switching, the same wrinkle holding load distribution as in the case of the tri-press is quickly reproduced regardless of the individual difference of the press machine 150, and the same as in the previous embodiment. The effect is obtained. In this case, the hydraulic cylinder 244 is a hydraulic cylinder according to claim 1.
This corresponds to a pressure cylinder, and the wrinkle holding load Fso corresponds to a set press load.

If the air pressure Pf of the cylinder 250 is changed, the bending point load Fc changes. For example, when the load change characteristic shown by the solid line in FIG. 23 is obtained, the air pressure Pf of the cylinder 250 is increased. Then, as for the load change characteristic, the bending point load Fc increases as shown by the one-dot chain line. Conversely, when the air pressure Pf decreases, the load change characteristic decreases as shown by the two-dot chain line. Therefore, similarly to steps Q23 to Q25 in FIG. 12, four press loads Fp are detected by the strain gauge 230, and the four press loads Fp are set so that each of the press loads Fp substantially matches the predetermined wrinkle holding load Fso. If the air pressure Pf in the cylinder 250 at each location is independently adjusted by switching the ON / OFF supply / exhaust valve 272, the press machine 150
Regardless of the individual difference, the wrinkle holding load distribution substantially the same as in the case of the tri-press is quickly reproduced, and the same effect as that of the above embodiment can be obtained .

The adjustment of the oil pressure Pd and the air pressure Pf does not necessarily have to be performed automatically, and the ON / OFF oil supply / drain valve 260, ON, OFF is operated by a switch operation of an operator.
The pressure may be adjusted by switching the supply / exhaust valve 272. The four inner plungers 168 are connected to the inner slide 164 in the same manner as the outer plunger 166, so that the press load is detected by a strain gauge and the press load is reduced to I.
The relative distance and the hydraulic pressure are adjusted in the same manner as in the first embodiment so as to substantially match the molding load set in advance on the D card or the like.

Although several embodiments of the present invention have been described in detail with reference to the drawings, the present invention can be implemented in other embodiments.

For example, in the first embodiment, the strain gauges 90 are attached to the four frames 12 so that the pressing load Fp
Is detected, but a press load can be detected by attaching a strain gauge to the plunger 18 as in the case of the double-action press machine 150.

In the first embodiment, the hydraulic cylinder Pa is locked in a state where the wrinkle pressing load is not applied in a state where the air cylinder for holding the wrinkle is locked at the lower end and the press slide 14 is lowered to the bottom dead center. Although the case has been described, it is also possible to adjust the four hydraulic pressures Pa so that a predetermined press load distribution is obtained in a state where the air cylinder for wrinkle press is operated so as to obtain a predetermined wrinkle press load. . In this case, the press load Fp detected by the strain gauge 90 is a total load obtained by adding the forming load and the wrinkle holding load. Therefore, the ID card 118 stores the wrinkle holding load Fso together with the forming load Ffo. Or the total load needs to be stored.

In the embodiment shown in FIG. 18, the outer-side press load Fp is set in a load range in which the outer-side press load Fc is equal to or greater than the bending point load Fc, in other words, in the load region in which the piston 266 of the cylinder 250 retreats. , Bending point load F
The press load Fp may be set within a load range of c or less. In that case, the load can be adjusted in the same manner as in the first embodiment.

Conversely, in the first embodiment, the cylinder 50
It is also possible to set the press load Fp in the load region where the piston 66 moves backward. In this case, the load adjustment may be performed in the same manner as the setting of the outer-side press load Fp in the embodiment of FIG. The same applies to the inner-side press load of the embodiment in FIG.

In the above embodiment, the case where the relative distances h ₁ and h ₂ , the hydraulic pressures Pa and Pd, and the air pressure Pf are adjusted while the press machines 10 and 150 are operated by the switch operation of the operator has been described. The machines 10, 150 can also be started up automatically and their adjustments made fully automatic.

In the above embodiment, the strain gauges 90 and 230 are used to detect the load of each part. However, other various strain sensors can be used.

In the above embodiment, when the actual press load is measured, the strain gauge 110 or the electromagnetic oscilloscope 11 is used.
4 was used, but other load detecting means such as a magnetostrictive force sensor for measuring a load utilizing the magnetostriction phenomenon may be used, or another type of recording means excellent in high-speed tracking performance may be used. It is possible. The strain gauge 2 is attached to the plunger 166.
When there is almost no difference between the load value detected by the strain gauge and the actual load value, for example, when load detection is performed with the 30 attached, it is not always necessary to perform load measurement as described above and correct it. Instead, the detected load value of the strain gauge can be used as it is.

In the above-described embodiment, the die information is stored in the ID card 118. However, if the type of die to be used is small, the type of die is stored in the computer of the press machine. The mold information may be stored in association with the information. Other storage means, such as a floppy disk or a magnetic tape, can be used, or the operator can make input settings by key input or the like.

In the above-described embodiment, the case where the present invention is applied to the press machines 10 and 150 that perform drawing is described. However, the present invention is similarly applied to various other press machines such as those that perform bending. Can be applied.

Although not specifically exemplified, the present invention can be embodied with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram illustrating an example of a single action press machine in which a press load is set according to a method of the present invention.

FIG. 2 is a diagram illustrating a configuration of a connecting portion between a plunger and a press slide of the press machine in FIG. 1;

FIG. 3 is a block diagram illustrating a control system of the press machine in FIG.

FIG. 4 is an example of a data map showing a correlation between a press load Fp and a strain gauge output signal Sε stored in a machine information memory of FIG. 3;

FIG. 5 is a view showing a state in which a load measuring table is provided in the press machine of FIG. 1 for measuring an actual press load.

6 is a diagram showing a result of measuring a strain gauge output signal Sε and a press load Fp while changing the press-in amount in the case of FIG. 5, and is basic data of the data map of FIG. 4;

FIG. 7 is a diagram illustrating a relationship between a fluctuation waveform of a press load Fp and a wrinkle holding load Fs and a forming load Ff in the press machine of FIG.

8 is a diagram showing the display / operation panel of FIG. 3 together with FIGS. 9 and 10. FIG.

9 is a diagram showing a display / operation panel together with FIGS. 8 and 10. FIG.

FIG. 10 is a diagram showing a display / operation panel together with FIGS. 8 and 9;

In the press machine 11 1 is a flow chart for explaining a procedure for adjusting the relative distance h ₁ and the hydraulic Pa according to a preset molding force.

FIG. 12 is a diagram illustrating a continuation of the flowchart in FIG. 11;

[13] FIG 11 is a diagram for explaining the operation in adjusting the relative distance h ₁ as substantially to match the total pressing load Fpt and the total forming load Ffot to FIG 12.

14 is a diagram illustrating a case where four press loads Fp deviate from a press-in amount due to a variation in parallelism of a press slide or the like in the press machine in FIG.

FIG. 15 is a diagram illustrating a case in which, in the press machine of FIG. 1, a hydraulic pressure Pa is changed to change a change characteristic of a press load Fp with respect to a press-in amount.

FIG. 16 is a diagram for explaining another embodiment of the present invention.
It is a flowchart used instead of.

In the embodiment of FIG. 17 FIG. 16 is a diagram for explaining the operation when the total press load Fpt to adjust the relative distance h ₁ as substantially coincides with the total forming load Ffot.

FIG. 18 is an overall configuration diagram illustrating an example of a double action press machine in which a press load is set according to the method of the present invention.

19 is a diagram illustrating a configuration of a connecting portion between an outer plunger and an outer slide of the press machine in FIG.

FIG. 20 is a view showing a change characteristic of a total press load Fpt on the outer side with respect to a press-in amount in the press machine of FIG. 18;

In the press machine [21] 18, a diagram illustrating the operation in adjusting the relative distance h ₂ as the outer side of the total press load Fpt is substantially coincident with the total blank-holding force Fsot, (a) is FIG. 13B corresponds to FIG.
Corresponding to

FIG. 22 is a diagram illustrating a case where the hydraulic pressure Pd is changed to change the change characteristic of the outer-side press load Fp with respect to the press-in amount in the press machine of FIG. 18;

FIG. 23 is a diagram illustrating a case where the air pressure Pf is changed to change the change characteristic of the outer-side press load Fp with respect to the press-in amount in the press machine of FIG. 18;

[Explanation of symbols]

10: Press machine 14: Press Slide 18: plunger (vertical driving member) 20: die (press upper mold) 44: Hydraulic Cylinders 150: press machine 156: pressure ring (press upper die) 160: outer slide (Press slide) 162: punch type (press upper die) 164: inner slide (press slide) 166: outer plunger (vertical driving member) 168: inner plunger (vertical driving member) 244: hydraulic Cylinders Pa, Pd: hydraulic Fp: Press load Ffo: Forming load (set press load) Step Q23, 24: Fluid pressure adjustment step Step Q25: Load detection step

Continuation of front page (58) Fields investigated (Int.Cl. ⁶ , DB name) B30B 15/06 B30B 15/14 B30B 15/28

Claims (1)

(57) [Claims] The hydraulic oil is confined in a substantially constant space.
It is connected to the vertical driving member via a plurality of hydraulic cylinders and, together be moved vertically and substantially integrally upper and lower drive member, the plurality of hydraulic cylinders during pressing it
A press slide for transmitting a press load to a plurality of positions via the plurality of hydraulic cylinders by being driven in , and a press machine for performing press working by vertically moving a press upper die attached to the press slide; a setting method, a load detection step for detecting a pressing load of a plurality of locations corresponding to said plurality of hydraulic cylinders, the hydraulic pressure in the plurality of hydraulic cylinders during non pressing its
Adjust each independently to adjust the amount of press slide
And a fluid pressure adjusting step of changing a load change characteristic with respect to the plurality of locations so that the press load at the plurality of locations substantially matches a predetermined set press load.