JPH08300058A - Pressing method, pressing device and pin transmission load detecting device - Google Patents

Abstract

PURPOSE: To precisely diagnose the suitability of a blank holder, to finely control the distribution of surface pressure of the blank holder, and on the other side, to easily ad rapidly trace the cause or repair it, in the case of the blank holder being not suitable. CONSTITUTION: A load detecting die stand 102 is arranged between a bolster 12 and a punch die 10, and, a load detecting connection pin 104 having the dimension of length almost same as the dimension of height of the load detecting die stand 102 is connected to all the cushion pin 22, and the transmission load of all the cushion pin 22 is detected individually with a load sensor 108 attached on the load detecting connection pin 104.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press working method and a press working apparatus capable of diagnosing with high accuracy whether or not wrinkle holding is properly performed during drawing, and a pin suitably used for the method and apparatus. The present invention relates to a transmission load detection device.

[0002]

[Prior art]

(A) A cushion pad to which a predetermined movement resistance is applied, and (b) a plurality of cushion pins interposed in parallel between the cushion pad and the wrinkle holding ring. The peripheral edge of the press material is wrinkled between the holding ring and the die die, and in that state, the wrinkle holding ring and die die together with the cushion pad resist the movement resistance in the pressing direction with respect to the punch die. 2. Description of the Related Art A press working apparatus is widely used which draws the press material along the punch-shaped forming surface by being relatively moved. The cushion pad is designed to be lowered in a substantially horizontal posture against the movement resistance, and the punch type is positioned and fixed on a bolster arranged above the cushion pad. The plurality of cushion pins are mounted on the cushion pad by penetrating through a through hole provided vertically penetrating the punch type and the bolster, and support the wrinkle holding ring at the upper end portion. It is usual to perform drawing work by vertically moving the die mold by the vertical driving means above the punch mold and the wrinkle holding ring.

Further, (c) a plurality of fluid pressure cylinders, which are arranged on the cushion pad and on which the plurality of cushion pins are respectively placed, and in which pressure chambers communicate with each other, are provided to perform wrinkle pressing. There is also known a press working apparatus in which the pistons of a plurality of fluid pressure cylinders are brought into a neutral state so that the wrinkle holding load is evenly acted on the wrinkle holding ring via a plurality of cushion pins. The device described in Japanese Patent Application Laid-Open No. 6-304800 is an example thereof, and in such a press working device, regardless of variations in the length dimension of the cushion pin, inclination of the cushion pad, etc. The wrinkle presser load is evenly applied to the wrinkle presser ring via the fluid, and a desired wrinkle presser load distribution can be obtained according to the arrangement of the cushion pins.

Here, in order to uniformly apply the wrinkle pressing load as described above, the pistons of all the fluid pressure cylinders are driven into the cylinder during the drawing process regardless of variations in the length of the cushion pin. In other words, it is necessary to keep the piston in a neutral state so that the stroke end is not reached. Therefore, the average thrust dimension Xav of the piston of the hydraulic cylinder as the fluid pressure cylinder, the pressure receiving area As of the hydraulic cylinder, the bulk elastic coefficient K of the fluid used, the initial volume V of the fluid, the wrinkle pressing load Fs, the number of cushion pins used. That is, the initial hydraulic pressure Pso of the hydraulic cylinders, that is, the hydraulic pressure before drawing is determined based on the number n of the hydraulic cylinders involved in the wrinkle pressing so as to satisfy the following expression (1). The average drive-in dimension Xav is the drive-in stroke of the piston for bringing all the cushion pins into contact with the wrinkle holding ring,
Regardless of variations in the length of the cushion pin and inclination of the cushion pad, the cushion pin is pushed into the cylinder by all the cushion pins and can reach the stroke end (barrel) regardless of impact during drawing. It is determined in advance by experiments etc. so that it does not exist. In addition, the initial volume V of the fluid is the pressure chamber of the hydraulic cylinders and the fluid in the series of hydraulic circuits communicating with the pressure chambers when the pistons of all the hydraulic cylinders are positioned at the protruding ends. The total volume. Xav = (Fs−n · As · Pso) V / n ² · As ² · K (1)

Further, Japanese Laid-Open Patent Publication No. 6-212225 discloses a pressure equalizing state in which the pistons of all the hydraulic cylinders are in a neutral state from the relationship between the hydraulic pressure of the hydraulic cylinders during drawing, that is, the generated hydraulic pressure and the wrinkle holding load. It is possible to diagnose the wrinkle presser load area where it is obtained, and to monitor whether or not drawing processing is being performed in a pressure equalized state by checking whether the generated hydraulic pressure is substantially equal to the preset hydraulic pressure. Proposed.

[0006]

As described above, conventionally, when the pistons of all fluid pressure cylinders are in the neutral state, it is determined that the pistons are in the equalizing state. However, the pressure is transmitted to the wrinkle holding ring via each cushion pin. Since it is not known whether or not the actual loads to be applied are substantially equal, it is not always possible to obtain high reliability, and it is not possible to manage the transmission load for each cushion pin in a very fine manner. In addition, when monitoring whether or not the generated fluid pressure is in a pressure equalized state by comparing it with a predetermined set fluid pressure, for example, in the case of a non-equalized state due to a malfunction of the piston of the fluid pressure cylinder, which fluid pressure is It was impossible to know if there was a cause in the cylinder, and it was extremely troublesome to investigate the cause and repair it. Although these are problems relating to a press working apparatus provided with a fluid pressure cylinder for pressure equalization, in a press working apparatus not provided with a fluid pressure cylinder for pressure equalization,
Since there is no means for checking whether or not the wrinkle pressing is properly performed, there is no choice but to judge whether the wrinkle pressing is good or bad by looking at the actual press-formed product.

The present invention has been made in view of the above circumstances. The object of the present invention is to determine whether or not the wrinkle retainer is appropriate with a high degree of accuracy and to control the load distribution of the wrinkle retainer in an extremely fine manner, while the wrinkle retainer is being controlled. It is to make it possible to easily and promptly investigate the cause and repair the problem when it is not appropriate.

[0008]

[First Means for Solving the Problems]
(A) A cushion pad to which a predetermined movement resistance is applied, and (b) a plurality of cushion pins interposed in parallel between the cushion pad and the wrinkle holding ring. The peripheral edge of the press material is wrinkled between the holding ring and the die die, and in that state, the wrinkle holding ring and die die together with the cushion pad resist the movement resistance in the pressing direction with respect to the punch die. In the pressing method for drawing the press material along the punching surface of the punch die by the relative movement, (c) a pin for detecting an individual transmission load of each of the plurality of cushion pins during the drawing. A transmission load detecting step, and (d) a predetermined characteristic value of each transmission load of the plurality of cushion pins is defined as a predetermined criterion. And having a diagnostic process for determining the appropriateness of the blank-holding depending on whether the foot.

[0009]

In the press working method as described above, the transmission loads of the plurality of cushion pins are respectively detected, and whether or not the predetermined characteristic value of the transmission load satisfies the predetermined criterion. While the appropriateness of the wrinkle retainer is determined by the, the transmission load of the cushion pin directly corresponds to the wrinkle retainer load applied from the cushion pin to the wrinkle retainer ring. Not only the press processing equipment that it has but also the press processing equipment that does not have it can diagnose with high accuracy whether or not wrinkle pressing is being performed based on the predetermined wrinkle pressing load distribution determined by the criterion, and the wrinkle pressing load distribution can be cushioned. You can manage each pin very finely. In addition, the transmission load of a plurality of cushion pins is detected, and the suitability of the crease presser is determined based on whether or not the judgment standard is satisfied.Therefore, by detecting the transmission load corresponding to the cushion pin, the judgment standard is determined. It is possible to easily specify a cushion pin having a transmission load that does not satisfy the above condition, and it is possible to easily and quickly investigate the cause and repair.

Here, the characteristic value of the transmission load is a change waveform, peak value, average value, frequency of load vibration, damping coefficient, etc. of the transmission load in one drawing process. Further, the criterion is a reference characteristic value that is set according to the wrinkle holding load or the like so as to obtain a desired press quality, that is, a reference waveform, a reference peak value, a reference average value, a reference frequency, a reference attenuation coefficient, or the like. It is whether or not the variation in the characteristic value of the transmission load of the plurality of cushion pins is within a predetermined allowable range. When the judgment criterion is the reference characteristic value, different judgment criteria may be set for each cushion pin even when the suitability of the transmission load of all cushion pins is diagnosed according to one judgment criterion. May be.

[0011]

[Second Means for Solving the Problems] The second invention is
(A) A cushion pad to which a predetermined movement resistance is applied, (b) a plurality of fluid pressure cylinders arranged on the cushion pad and having pressure chambers communicating with each other, and (c) a plurality of fluid pressures. A plurality of cushion pins interposed between the cylinder and the wrinkle holding ring, and when wrinkling the peripheral edge portion of the press material between the wrinkle holding ring and the die die based on the movement resistance,
By making the pistons of the plurality of fluid pressure cylinders respectively in a neutral state, the wrinkle holding load is evenly applied to the wrinkle holding ring, and in that state, the wrinkle holding ring and the die die together with the cushion pad move the movement resistance. In the press working method of drawing the press material along the forming surface of the punch die by moving the punch material relative to the punch die in the pressing direction against the punch die, A pin transfer load detecting step of detecting each transfer load of the cushion pin, and (e) each cushion when the predetermined characteristic value of each transfer load of the plurality of cushion pins satisfies a predetermined criterion. And a diagnosing step of judging a pressure equalized state in which the wrinkle pressing load is evenly transmitted through the pin. That.

[0012]

That is, the second invention corresponds to an embodiment of the first invention, and the first invention is applied to a press working apparatus having a fluid pressure cylinder for pressure equalization, and wrinkles are not formed. The suitability of the presser foot is diagnosed as to whether or not the pressure is equalized, and the same effect as the first invention can be obtained.

[0013]

A third aspect of the present invention is the press working method according to the second aspect, wherein the diagnostic step is
When the predetermined load values or vibration frequencies of the transmission loads of all the cushion pins are within the preset setting range, it is judged that the pressure is equalized, and at least a part of them is exceeded if even one pin exceeds the preset range. It is judged that the pistons of the fluid pressure cylinders are in the cylinder thrusting state, and if even one of them is below the setting range, it is judged that at least some of the pistons of the fluid pressure cylinders are in the unactuated state. It is characterized by being.

[0014]

In other words, the load value of the transmission load of the cushion pin is higher when the piston of the fluid pressure cylinder is pushed in and the body strikes than when the piston is in the neutral state. When the piston of the cylinder is not actuated, it is lower than when the piston is in the neutral state. Also, the vibration frequency of the transmission load of the cushion pin is higher when the piston of the fluid pressure cylinder pierces the body than when the piston is in the neutral state, that is, when vibration of the fluid pressure occurs. In the case of operation, the transmission load itself is substantially zero or relatively small, and almost no vibration occurs, so that it is lower than in the case where the piston is in the neutral state. Therefore, if the predetermined load values or vibration frequencies of the transmission loads of all the cushion pins are within the setting range, it can be determined that the pressure is equalized, and if even one of the cushion pins exceeds the setting range, it can be determined that the body is in the thrust state. If even one line is below the set range, it can be determined that the pressure is not equalized. Therefore, for example, in the case of the cylinder thrusting state, the initial fluid pressure of the fluid pressure cylinder is increased, while in the case of the non-equalized state. In this case, the initial fluid pressure can be reduced and the fluid pressure can be adjusted so as to be in a pressure-equalized state.

Further, according to the present invention, it is determined whether or not the pressure is equalized depending on whether or not the predetermined load values or the vibration frequencies of the transmission loads of all the cushion pins are within a predetermined setting range. If it is within the range, not only the pressure equalizing state but also the predetermined load value of all the cushion pin transmission loads or the vibration frequency is within the set range, respectively. The street press quality is reproduced with high accuracy.

Since the above-mentioned vibration frequency is the reciprocal of the vibration period, it is possible to judge whether the pressure is equalized, the body is stuck or the pressure is not equalized by using the vibration period. Is substantially the same and is included in the technical scope of the present invention.

[0017]

A fourth invention is the press working method according to the first invention or the second invention, wherein the predetermined characteristic value of the transmission load is the transmission load in one drawing process. Is determined by including at least one of the peak value, the average value, and the vibration frequency of the waveform.

[0018]

In other words, the peak value, the average value, or the vibration frequency of the waveform of the transmitted load can be relatively easily obtained from the waveform of the transmitted load and can be recognized as a numerical value. It is possible to easily and accurately determine whether or not the pressure equalization state and the wrinkle retainer are appropriate, as compared with the case of using. Moreover, since the amount of data required is smaller than when the waveform itself is stored, the storage capacity can be small when the determination reference is stored in the storage means such as a memory.

[0019]

[Fifth Means for Solving the Problems]
(A) A cushion pad to which a predetermined movement resistance is applied, and (b) a plurality of cushion pins interposed in parallel between the cushion pad and the wrinkle holding ring. The peripheral edge of the press material is wrinkled between the holding ring and the die die, and in that state, the wrinkle holding ring and die die together with the cushion pad resist the movement resistance in the pressing direction with respect to the punch die. In a press working apparatus that draws the press material along the punch-shaped forming surface by being relatively moved, (c) a pin that detects each transmission load of each of the plurality of cushion pins during the drawing work. A transmission load detecting means, and (d) a predetermined characteristic value of the transmission load, which is predetermined for proper wrinkle holding. Judgment criterion storage means for storing the judgment criterion, and (e) a predetermined characteristic value of each transmission load of the plurality of cushion pins detected by the pin transmission load detection means is stored in the judgment criterion storage means. And a diagnostic means for judging whether or not the wrinkle presser is appropriate depending on whether or not the above-mentioned judgment criterion is satisfied.

[0020]

In other words, the press working apparatus of the fifth invention can suitably carry out the press working method of the first invention, and the pin transmission load detecting means can be used to remove a plurality of cushion pins. Each of the transmission loads is detected, and the appropriateness of the wrinkle presser is judged by the diagnostic means depending on whether or not the predetermined characteristic value of the transmission load satisfies the judgment standard stored in the judgment standard storage means. The same effect as the first invention can be obtained.

[0021]

According to a sixth aspect of the invention, the cushion pad is lowered in a substantially horizontal posture against the movement resistance, and the punch type is arranged above the cushion pad. Positioned and fixed on a bolster provided, the plurality of cushion pins are placed on the cushion pad by penetrating through a through hole provided vertically through the punch type and the bolster.
A pin transmission load detecting device used as the pin transmission load detecting means in the press working device according to the fifth aspect of the present invention, which supports the wrinkle pressing ring at an upper end portion, comprising: (a) the bolster and the punch type. And a load detection mold base provided with a through hole that allows the cushion pin to vertically pass therethrough,
(B) A load sensor having a length dimension substantially the same as the height dimension of the load detection mold base and connected in series to each of the plurality of cushion pins, and a load sensor for detecting a transmission load of the cushion pin is attached. And a plurality of connecting pins for detecting the load.

[0022]

In other words, the pin transmission load detecting device is preferably used for detecting the individual transmission loads of the cushion pins when the press working method of the first invention is carried out. A load detection mold stand is inserted between the bolster and the punch die, and a load detection connecting pin that has a length sensor and a length dimension that is approximately the same as the height dimension of the load detection mold stand is attached. Since the plurality of cushion pins are connected in series, the load sensor attached to the load detection connecting pin can detect the transmission load of each cushion pin during the drawing process. In such a case, such a pin transmission load detection device uses a cushion pin equipped with a load detection connecting pin and a load detection mold base on the bolster when the mold is replaced, and the conventional press machine is used. The processing device can be used as it is, and no large-scale modification or design change is required, and it can be easily and inexpensively applied.

[0023]

Embodiments of the present invention will now be described in detail with reference to the drawings. In FIG. 1, a bolster 12 to which a punch die 10 is attached is disposed substantially horizontally on a base 16 via a press carrier 14, while a slide plate 20 to which a die die 18 is attached is moved up and down by a vertical drive mechanism (not shown). It is designed to be driven in the direction. The bolster 12 is provided with a large number of through holes 24 in a grid pattern for disposing the cushion pins 22.
Below the bolster 12, these cushion pins 22 are provided.
A cushion pad 26 for supporting the is arranged in a substantially horizontal posture. The cushion pin 22 is the punch type 10 described above.
It supports the wrinkle pressing ring 28 arranged together with the wrinkle pressing ring 28, and an arbitrary number of the wrinkle pressing ring 28 are arranged at predetermined positions according to the shape of the wrinkle pressing ring 28. Punch type 1
0 has a plurality of through holes corresponding to the positions of the cushion pins 22. Also, cushion pad 2
6 denotes a large number of hydraulic cylinders 3 corresponding to the through holes 24.
0, and the lower end portions of the cushion pins 22 are brought into contact with the piston rods of the hydraulic cylinders 30, respectively. The hydraulic cylinder 30 corresponds to a fluid pressure cylinder for pressure equalization.

The cushion pad 26 is arranged in the press carrier 14 so as to be movable in the vertical direction, and serves as a movement resistance imparting means.
Is urged upward by. The pressure chamber of the air cylinder 32 is communicated with an air tank 34, and the air tank 34 is supplied with pressurized air from an air pressure source 36 via an air pressure control circuit 38. An on-off valve 37 and an air pressure sensor 39 are connected to the air tank 34, and the air tank 34 and the air cylinder 3 are controlled by the air pressure control circuit 38 and the on-off valve 37.
The air pressure Pa in 2 is adjusted according to the wrinkle pressing load.
That is, when the die die 18 is lowered together with the slide plate 20, the air pressure Pa of the air cylinder 32 is increased.
The peripheral edge portion of the press material 40 is wrinkled and held between the die die 18 and the wrinkle holding ring 28 according to the urging force based on
When the wrinkle pressing ring 28 and the die die 18 are further lowered together with the cushion pad 26 against the urging force of the air cylinder 32 in that state, drawing is performed along the forming surface of the punch die 10. The urging force of the air cylinder 32 corresponds to the movement resistance of the cushion pad 26.

The pressure chambers of the plurality of hydraulic cylinders 30 are
While communicating with each other via a pipe 46,
The pipe 46 is a pipe 50 through a flexible tube 48.
The hydraulic oil pumped from the tank 54 by the air-driven hydraulic pump 52 is supplied through the check valve 56. A hydraulic control circuit 58 equipped with a relief valve or the like is connected to the pipe 50, and the pipe 5 is connected by the hydraulic control circuit 58 and the hydraulic pump 52.
0 or the hydraulic pressure Ps of the hydraulic oil in the hydraulic cylinder 30 causes all the hydraulic cylinders 30 involved in the wrinkle holding during the drawing process, that is, the pistons of the hydraulic cylinder 30 in which the cushion pin 22 is arranged to be in a neutral state. Is regulated to.
As a result, the wrinkle pressing load is uniformly applied to the wrinkle pressing ring 28 from the plurality of cushion pins 22. The oil pressure Ps is detected by an oil pressure sensor 60 connected to the pipe 46. In this embodiment, a pressure equalizing cushion device 44 is configured by including the cushion pin 22, the cushion pad 26, the hydraulic cylinder 30, and the air cylinder 32.

Here, in the press working apparatus of the present embodiment, the pin transmission load detecting device 1 for detecting the individual transmission loads Fp of the plurality of cushion pins 22 respectively.
00 is attached. The pin transmission load detecting device 100 is an embodiment of the invention as set forth in claim 6, and is connected in series to each of the load detecting mold base 102 fixedly mounted on the bolster 12 and the plurality of cushion pins 22. A plurality of load detecting connecting pins 104,
0 is arranged on the load detection mold base 102. The load detecting mold base 102 is provided with a large number of through holes 106 corresponding to the through holes 24 in a grid pattern so that the wrinkle pressing ring 28 can be used even when the die such as the punch die 10 or the wrinkle retaining ring 28 is different. The cushion pin 22 arranged at an arbitrary position according to the shape of the above is allowed to vertically penetrate. The through-holes 106 do not need to penetrate the cushion pins 22 one by one, and may be large holes that allow a plurality of cushion pins 22 to penetrate.

The load detecting connecting pin 104 is integrally connected to the upper end of the cushion pin 22 by a fixing means such as a screw, and is attached to all the cushion pins 22 used. In addition, a load sensor 108 such as a strain gauge that detects the transmission load Fp is attached. The length dimension of the load detecting connecting pin 104 is substantially the same as the height dimension of the load detecting mold base 102, and the relative heights of the punch die 10 and the wrinkle holding ring 28 are the same as those of the pin transmission load detecting device 100. It is substantially the same as before mounting, and the pin transmission load detection device 100
Even if is attached, the same drawing process is performed. An identification number is set for each load detection connecting pin 104, and the pin transmission load Fp detected by the load sensor 108 is distinguished by the identification number. When the arrangement position of the cushion pin 22 to which the load detecting connecting pin 104 is attached is set according to the identification number, the pin transmission load Fp can be distinguished by the arrangement position.

On the other hand, the pressure control of the hydraulic pressure Ps and the air pressure Pa is performed by the control unit 62 shown in FIG. 2, and the air pressure sensor 39, the hydraulic pressure sensor 60, and the load sensor 108 are controlled by the control unit 62. Signals representing the air pressure Pa, the oil pressure Ps, and the pin transmission load Fp are supplied via an amplifier or the like. The control unit 62 includes a CPU,
The air pressure Pa, which is constituted by including a microcomputer including a RAM, a ROM, etc., by performing signal processing according to a program stored in advance in the ROM,
The hydraulic pressure Ps is regulated, the pressure equalization diagnosis is performed on the ON line, and the wrinkle holding load region where the pressure equalization state is obtained is diagnosed. The control unit 62 is also connected to a display / operation panel 68, and is supplied with a trial shot switch signal SS indicating that the trial shot switch of the press working device has been turned ON and a stroke signal SD indicating a press stroke. It is like this. Display / operation panel 68
Is equipped with an indicator, an operation switch and the like shown in FIG. 3, and the hydraulic pressure Ps and the air pressure Pa are indicated by the indicator 7 respectively.
It is displayed at 0,71.

Further, the control unit 62 is
Machine information unique to the press working apparatus, for example, the weight Wa of the cushion pad 26 and the average weight W of the cushion pin 22.
p, pressure receiving area Aa of the air cylinder 32, hydraulic cylinder 3
The pressure receiving area As of 0 is stored in the RAM or the like, and the die information from the ID card 66 (see FIG. 1) attached to the punch die 10 via the transceiver 64, for example, the weight of the wrinkle holding ring 28. Wr and cushion pin 22
No. of used n, standard wrinkle pressing load Fso that can obtain appropriate press quality, standard maximum peak value Fp of pin transmission load Fp
The maxo, reference average value Fpavo, reference vibration frequency ωo, etc. are read. The ID card 66 transmits the mold information and stores the contents of the mold information by the storage function of storing mold information unique to the mold and the data acquisition signal and the data rewriting signal supplied from the transceiver 64. It has a function to rewrite.

The pin transmission load Fp oscillates due to, for example, hydraulic vibration of the hydraulic cylinder 30 as shown in FIG. 4, the maximum value of which is the maximum peak value Fpmax, and from the press stroke ST1 of the maximum peak value Fpmax, for example. The average of the pin transfer load Fp up to the bottom dead center position ST2 is the average value Fpav, the reciprocal of the vibration cycle T of the pin transfer load Fp is the vibration frequency ω, and the reference maximum peak value Fpmaxo,
The reference average value Fpavo and the reference vibration frequency ωo are in the case of a pressure equalization state in which when proper press quality is obtained, in other words, all the pistons of the hydraulic cylinders 30 involved in the wrinkle presser are in a neutral state during drawing. The data. Average value F
Although pav may be the average value of the maximum and minimum peak values between the press strokes ST1 and ST2, it is desirable to obtain it by integrating the pin transmission load Fp. Further, the vibration frequency ω is substantially constant regardless of the press stroke, and can be obtained, for example, from the time interval (vibration cycle T) between adjacent maximum peak values. The maximum peak value Fpmax, the average value Fpav, and the vibration frequency ω vary depending on whether the piston of the hydraulic cylinder 30 in which the cushion pin 22 is arranged is in the neutral state or not.
Maximum peak value Fpmax when 0 piston is not activated
, The average value Fpav, and the vibration frequency ω are lower than those in the neutral state, but when the piston of the hydraulic cylinder 30 is thrust, the maximum peak value Fpmax and the average value Fpa.
Both v and vibration frequency ω are higher than in the neutral state.

The reference maximum peak value Fpmaxo, the reference average value Fpavo, and the reference vibration frequency ωo are set for each press working apparatus, but the reference average value Fpavo is not influenced by the machine difference of each press working apparatus. It is not always necessary to set it for each press working device. Further, the reference maximum peak value Fpmaxo, the reference average value Fpavo, and the reference vibration frequency ωo can be set individually for each of the plurality of cushion pins 22, but in the present embodiment, all the pistons of the hydraulic cylinders 30 are neutral. Since there is no variation in the characteristics of the transmission load Fp of each cushion pin 22, the single reference maximum peak value Fpmaxo, reference average value Fpavo, and reference vibration frequency ωo are set. For example, a cushion pad 2 is provided by disposing a spacer or the like and causing a part of the hydraulic cylinders 30 to butt.
In the case of defining the approach position of the wrinkle pressing ring 28 and 6 to surely bring the other hydraulic cylinders 30 into the neutral state, the cushion pins 22 placed on the hydraulic cylinders 30 protruding from the cylinder are individually set to the above-mentioned reference. Maximum peak value F
pmaxo, standard mean value Fpavo, and standard vibration frequency ω
It is desirable to set o. Further, also in the press working apparatus which is not provided with the hydraulic cylinder 30 for equalizing pressure, since the characteristics of the pin transmission load Fp are different for each cushion pin 22, it is desirable to set them individually.

Next, an operation for performing pressure equalization diagnosis on the ON line by the signal processing of the control unit 62 will be described. The air pressure Pa of the air cylinder 32 is
In order to obtain the standard wrinkle pressing load Fso, the following equation (2)
And the pressure is adjusted by the air pressure control circuit 38 and the opening / closing valve 37. Weights Wa, Wp of the formula (2),
The value of the machine information stored in advance is used as the pressure receiving area Aa, and the value of the mold information read from the ID card 66 is used as the weight Wr and the number n of cushion pins used. Further, the initial hydraulic pressure Pso of the hydraulic cylinders 30 during non-press working is determined, for example, according to the equation (1) or a trial hit is performed, so that the pistons of all the hydraulic cylinders 30 provided with the cushion pins 22 are neutral. The hydraulic pump 52 and the hydraulic control circuit 58 are controlled so that the pressure equalizing state is achieved.
Is adjusted in advance by. It is also possible to initialize the initial hydraulic pressure Pso in the same manner as the ON line equalization diagnosis described below. Pa = (Fso + Wa + n · Wp + Wr) / Aa (2)

FIG. 5 is a functional block diagram for performing ON line pressure equalization diagnosis. The pressure equalization diagnosis process is performed according to the flowchart of FIG. Steps S1 to S3 of FIG. 6 are executed by the data storage unit 114 of FIG. 5. In step S1, it is determined whether or not the press stroke represented by the stroke signal SD is at top dead center. In S2, signals representing the pin transfer load Fp are read from all the load sensors 108 and stored in the data memory 116 in association with the press strokes. The pin transmission load Fp is converted into a digital signal by the A / D conversion unit 112, and then the data storage unit 1
14 is read. In step S3, it is determined whether or not the press stroke reaches the bottom dead center, and step S2 is repeated until the bottom stroke reaches the bottom dead center, and the pin transmission load Fp is read and stored in the data memory 116. These steps S1 to S3 correspond to the pin transmission load detecting step in claims 1 and 2, and these steps S1 to S3
The data storage unit 114 for executing No. 3 together with the pin transmission load detection device 100 constitutes the pin transmission load detection means of claim 5. The stroke signal SD can identify at least the top dead center and the bottom dead center, and is supplied from an absolute rotary encoder or the like that detects a crank angle.

In step S4, the characteristic value calculator 11 shown in FIG.
8 based on the load data of all the pin transfer loads Fp stored in the data memory 116, the maximum peak value Fpmax and the average value Fp as characteristic values thereof.
The av and the vibration frequency ω are calculated respectively. Next step S
5 and S8 are executed by the pressure equalizing diagnosis unit 120 of FIG. 5, and the reference maximum peak value Fpmaxo, the reference average value Fpavo, the reference vibration frequency ωo and the maximum peak value stored in the determination reference memory 122 are stored. Fpmax, average value Fp
By comparing av and the vibration frequency ω, it is diagnosed whether the pressure is equalized, the body is in a thrust state, or the pressure is not equalized. In step S5, the maximum peak value Fpmax and the average value F for each pin transmission load Fp
pav and the vibration frequency ω are the reference maximum peak values Fp, respectively.
It is judged whether or not it is within the allowable range set based on maxo, the reference average value Fpavo, and the reference vibration frequency ωo, and the maximum peak value Fpmax and the average value F for all the pin transfer loads Fp.
If both pav and the vibration frequency ω are within the permissible range, it is determined that the pressure is equalized and the pressure equalization is displayed in step S6. If any one of them deviates from the permissible range, step S7 is performed.
To display an error. The pressure equalization display and the abnormality display in steps S6 and S7 are executed by the display control unit 126 in FIG. 5, and are performed, for example, by turning on the normal lamp 82 and the abnormal lamp 84 of the display / operation panel 68 shown in FIG.

Further, in step S8, it is determined whether the maximum peak value Fpmax, the average value Fpav, or the vibration frequency ω of the pin transmission load Fp that caused the determination in step S5 to be NO is higher than the allowable range. If it is higher than the allowable range, it is determined that the cylinder is in a thrust state, and the initial hydraulic pressure Pso of the hydraulic cylinder 30 is increased by a predetermined value α in step S9. If it is lower than the allowable range, it is determined that the pressure is not equalized. Then, in step S10, the initial hydraulic pressure Pso is set to a predetermined value β.
Only lower. Wrinkle holding load, that is, air cylinder 3
When the air pressure Pa of 2 is constant, if the initial hydraulic pressure Pso is increased, the hydraulic pressure Psx generated during the drawing process is also increased. Therefore, the pushing amount of the piston of the hydraulic cylinder 30 is reduced and the cylinder thrust is eliminated, while the initial hydraulic pressure Pso is increased. When the hydraulic pressure is reduced, the hydraulic pressure Psx generated during drawing is also reduced.
Disappears. The steps S9 and S10 are executed by the hydraulic control unit 124 shown in FIG.
2 and the hydraulic control circuit 58 are controlled to regulate the pressure. As a result, the wrinkle holding load is transmitted to the wrinkle holding ring 28 substantially evenly through all the cushion pins 22, and the drawing process is performed with a predetermined wrinkle holding load distribution. Although illustration is omitted, if the determination in step S5 continues to be NO for more than a predetermined cycle, or if the initial hydraulic pressure Pso deviates from a preset range, step S5 The cushion pin 22 related to the pin transmission load Fp that caused the determination to be NO,
Specifically, the identification number of the load detecting connecting pin 104, the disposition position, etc. are displayed on the display.

In this embodiment, the maximum peak value Fpmax, the average value Fpav, and the vibration frequency ω for each pin transmission load Fp.
Are the reference maximum peak value Fpmaxo and the reference average value F, respectively.
Whether or not it is within the allowable range set based on pavo and the reference vibration frequency ωo is a judgment criterion, and the judgment criterion memory 122 corresponds to the judgment criterion storing means in claim 5. The allowable range is determined in consideration of error factors of each part, press quality, etc., and is set to a constant value up or down around a reference maximum peak value Fpmaxo, a reference average value Fpavo, and a reference vibration frequency ωo, or a fixed percentage width. It corresponds to the setting range of claim 3. The steps S5 and S8 correspond to the diagnosing step in claims 1 and 2, and the pressure equalizing diagnosis unit 120 that executes these steps S5 and S8 corresponds to the diagnosing means in claim 5.

The average values of the maximum peak value Fpmax, the average value Fpav, and the vibration frequency ω for all the pin transfer loads Fp are the indicators 85, 86, 87 of the display / operation panel 68 shown in FIG. In addition, the displayed values are displayed as the reference maximum peak value Fpmaxo and the reference average value Fpavo.
, The reference vibration frequency ω o is set by a setting operation means such as a push button so as to perform pressure equalization diagnosis, or the ID card 6
The stored contents of 6 can be rewritten. Therefore, the maximum peak value Fpmax, the average value Fpav, when an appropriate pressed product is obtained by trial press of a tri-press,
The average value of each of the vibration frequencies ω is directly used as the reference maximum peak value Fpmaxo, the reference average value Fpavo, and the reference vibration frequency ω.
It can be set in the ID card 66 as o.

Next, a case will be described in which the wrinkle pressing load region where a pressure equalized state is obtained is diagnosed by the signal processing of the control unit 62. FIG. 7 is a functional block diagram for diagnosing the pressure-equalizing wrinkle retainer load area.
The process is performed according to the flowchart in FIG. In step Q1 of FIG. 8, it is determined whether or not the changeover switch 72 of the display / operation panel 68 has been switched to "automatic" which indicates automatic pressure equalization diagnosis, and in step Q2, the operation preparation push button 74 of the display / operation panel 68 is also determined. It is determined whether or not is pushed. When the changeover switch 72 is switched to "automatic" and the operation preparation push button 74 is pressed, the wrinkle presser load Fs _n (n = 1 to 10) is set in step Q3. The wrinkle pressing load Fs _{n in} this case is an initial wrinkle pressing load when the die die 18 abuts the wrinkle pressing ring 28 with the press material 40 sandwiched therebetween, that is, before the volume of the air cylinder 32 decreases, and is from 20 tons to 200 tons. Are stored in advance at intervals of 20 tons in the range up to and are set in order from the high load side. The initial hydraulic pressure Pso of the hydraulic cylinder 30 is adjusted to a predetermined hydraulic pressure by the hydraulic pump 52 and the hydraulic control circuit 58.

At the next step Q4, the initial wrinkle holding load Fs is set to the wrinkle holding load F set at step Q3.
s _n , that is, the reference wrinkle holding load Fso of the above formula (2) is set to 200 ton at first, the wrinkle holding load Fs _n
The air pressure Pa is calculated and the pressure is adjusted in accordance with the arithmetic expression. This step Q4 and the step Q3 are
This is executed by the wrinkle presser load changing unit 128 in FIG. 7.
The number n of cushion pins used can be appropriately changed by the switch 75 of the display / operation panel 68 when the number is changed by trial hitting or the like.

When the air pressure adjustment in step Q4 is completed,
In step Q5, the buzzer sounds in a predetermined pattern indicating that the preparation is completed, and in step Q6, it is determined whether or not the test hitting switch of the press working apparatus has been turned ON. When an operator who hears the buzzer turns on the trial hitting switch and supplies the trial hitting switch signal SS, the buzzer is stopped in step Q7, and in the next step Q8, the press working apparatus is turned on by turning on the trial hitting switch. When performing the pressing process once, a signal representing the pin transfer load Fp is read from all the load sensors 108 and stored in the data memory 134. This step Q8 is performed by the data storage unit 13 of FIG.
0, the pin transfer load Fp is equal to the A / D
It is read into the data storage unit 130 via the conversion unit 112. Step Q8 corresponds to the pin transmission load detection step in claims 1 and 2, and the data storage unit 130 that executes this step Q8 constitutes the pin transmission load detection means of claim 5 together with the pin transmission load detection device 100. are doing.

Step Q9 is the characteristic value calculation unit 13 of FIG.
6 based on the load data of all the pin transfer loads Fp stored in the data memory 134, the maximum peak value Fpmax and the average value Fp as characteristic values thereof.
The av and the vibration frequency ω are calculated respectively. Next step Q
10 is executed by the pressure equalizing diagnosis unit 138 of FIG.
According to the judgment standard stored in the judgment standard memory 140, it is diagnosed whether or not the pressure is equalized. The criterion in this case is
For example, the maximum peak value F for all pin transmission loads Fp
If the variations in pmax, the average value Fpav, and the vibration frequency ω are within the respective predetermined allowable ranges, it is determined that the pressure equalization state is determined. In the pressure equalized state, all the pistons of the hydraulic cylinders 30 are in a neutral state, so that all the pin transmission loads Fp are substantially equal to each other, whereas in the non-pressure equalized state or the body thrust state, Since the hydraulic cylinder 30 of the portion is not in operation or bumps into the body, the variation in the pin transmission load Fp becomes large, and it is possible to determine whether or not the pressure is equalized based on the degree of this variation. With respect to the vibration frequency ω, it is also possible to set a judgment standard so as to judge that the pressure is equalized if it is within a predetermined frequency range based on the hydraulic vibration. The step Q10 corresponds to the diagnosis process of claims 1 and 2, the pressure equalizing diagnosis unit 138 that executes this step Q10 corresponds to the diagnosis means of claim 5, and the determination reference memory 140 determines the determination of claim 5. It corresponds to the reference storage means.

Then, the judgment in step Q10 is YE.
If S, that is, if the pressure is equalized, step Q1
1, the wrinkle holding load Fs on the display / operation panel 68_n10 each
Equal pressure wrinkle retainer load area display lamp 78 provided individually
The wrinkle presser load Fs this time _nTurn on the lamp corresponding to
I do. This step Q10 is performed by the display control unit 142 of FIG.
To be executed. Also, in the next step Q12, the wrinkle presser is
Load Fs_n= 20ton or not, in other words, total
Wrinkle retainer load Fs_nPressure equalization diagnosis was performed for
Judge whether or not Fs_nPush wrinkle until = 20 tons
Load Fs_nChange step Q3
repeat. Equalizing wrinkle retainer load area display lamp 78 of FIG.
The shaded area indicates the lighting area, that is, the wrinkle press that provides a pressure equalized state.
3 is an example of a load area.

As a result of the above, the diagnosis of the initial wrinkle presser load area where the pressure is equalized is completed, and when the mold is manufactured, the initial wrinkle presser load Fs is appropriately changed within the range of the pressure equalized presser foot load area. Wrinkle holding load Fs that can obtain various pressed products
And the wrinkle pressing load Fs can be adjusted according to the characteristics of the press material 40 in the actual press working line. When the desired wrinkle pressing load does not exist within the pressure-equalizing wrinkle pressing load region, the number of cushion pins 22 used, that is, the number n of the hydraulic cylinders 30 involved in the wrinkle pressing is changed or the initial hydraulic pressure Pso is changed. The initial wrinkle pressing load area for pressure equalization may be changed so that the pressure equalizing state can be obtained with a desired wrinkle pressing load.

Here, the press working apparatus of the present embodiment detects the transmission loads Fp of the plurality of cushion pins 22, respectively, and determines a predetermined characteristic value of the pin transmission load Fp, specifically, the maximum peak value Fpmax, The average value Fpav and the vibration frequency ω satisfy the predetermined determination criteria to determine whether or not the pressure is equalized, while the individual pin transmission loads Fp correspond to the corresponding cushion pins 22. Since it directly corresponds to the wrinkle presser load transmitted to the wrinkle presser ring 28 via the, the wrinkle presser load is distributed very finely for each cushion pin 22 while diagnosing whether or not the pressure is equalized. Managed.

In the pressure equalization diagnosis of the ON line, the maximum peak value Fpmax and the average value Fp of all the pin transmission loads Fp are detected.
Reference maximum peak value F where av and vibration frequency ω are the determination criteria
Based on pmaxo, reference average value Fpavo, and reference vibration frequency ωo, it is diagnosed whether the pressure is equalized or not based on whether or not it is within the allowable range. While increasing the initial oil pressure Pso,
If even one is below the allowable range, it is determined that the pressure is not equalized and the initial hydraulic pressure Pso is lowered. Therefore, the pressure is automatically controlled so that the equalized state is obtained. The burden is reduced and the occurrence of defective products is suppressed. Especially, in this case, not only the pressure equalizing state but also the maximum peak value Fpmax and the average value F of all the pin transfer loads Fp are obtained.
pav and vibration frequency ω are the criteria for judgment: maximum standard peak value Fpmaxo, standard average value Fpavo, and standard vibration frequency ωo. Since drawing is performed within a predetermined allowable range, the desired press quality is highly accurate. Will be reproduced.

In the pressure equalizing diagnosis of the ON line, when the determination in step S5 is NO, that is, when the non-pressure equalizing state continues for a predetermined cycle or more, or the initial hydraulic pressure P
When so deviates from the predetermined range, the arrangement position of the cushion pin 22 and the load detection connecting pin 104 relating to the pin transmission load Fp that causes the determination in step S5 to be NO.
Since the identification number of is displayed on the display,
The hydraulic cylinder 30 or the cushion pin 22 having an abnormality can be easily identified by the display, and the cause can be investigated and repaired easily and quickly.

Further, in the diagnosis of the wrinkle pressing load region in which the pressure is equalized, the maximum peak value Fpmax of the pin transmission load Fp,
Since it is judged whether the pressure is equalized or not depending on whether the variations of the average value Fpav and the vibration frequency ω are within the predetermined allowable ranges, the pressure-equalized wrinkle pressing is performed by performing the trial hit while changing the wrinkle pressing load. The load area can be easily and accurately obtained.

Further, in this embodiment, since the maximum peak value Fpmax, the average value Fpav, and the vibration frequency ω are used as the characteristic values of the pin transfer load Fp, they can be relatively easily obtained from the waveform of the pin transfer load Fp. In addition to being able to recognize as a numerical value, it is possible to easily and accurately determine whether or not the pressure is equalized, as compared with the case where the waveform itself is used.
Further, since the required amount of data is small as compared with the case of storing the waveform itself, the storage capacity of the determination reference memories 122 and 140 can be small.

Further, in this embodiment, the transmission load F of all the cushion pins 22 is detected by using the pin transmission load detecting device 100.
Since each p is detected, by disposing the load measuring mold base 102 on the bolster 12 at the time of exchanging the mold, and by using the cushion pin 22 to which the load detecting connecting pin 104 is attached, The conventional press processing device can be used as it is, and it can be applied easily and inexpensively without requiring major modification or design change.

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

For example, in the above-described embodiment, the load detecting mold base 1
02 and the load detecting connecting pin 104 are used to detect the transmission load Fp of each cushion pin 22, but the transmission route of the wrinkle pressing load transmitted via the cushion pin 22, that is, the cushion pin 22 itself. A strain gauge, a load cell, etc. are provided between the boss portion of the wrinkle holding ring 28, between the boss portion and the cushion pin 22, between the piston of the hydraulic cylinder 30, the cushion pin 22, and between the hydraulic cylinder 30 and the cushion pad 26. It is also possible to attach the load sensor of No. 1 to detect the transmitted load.

In the above embodiment, the maximum peak value Fpmax, the average value Fpav, and the vibration frequency ω are used as the characteristic values of the pin transfer load Fp for diagnosis, but any one or two of them may be used. The diagnosis may be performed by using it, or the diagnosis may be performed by using other characteristic values such as an attenuation coefficient. A maximum value or a minimum value other than the maximum peak value can be used as the peak value, and the average value does not necessarily have to be obtained in the range from the press stroke ST1 to ST2.

Further, in the above embodiment, the pressure chambers of all the hydraulic cylinders 30 are communicated with each other, but it is also possible to divide into a plurality of areas and perform different pressure equalization control for each area. It suffices to set a judgment criterion for each area and perform pressure equalization diagnosis.

Further, although the press working apparatus of the above-mentioned embodiment is provided with the hydraulic cylinder 30 as a fluid pressure cylinder for equalizing pressure, other fluid pressure cylinders using a liquid other than hydraulic oil or a gel-like fluid may be used. Is also possible. The present invention can be similarly applied to a press working apparatus that does not include a fluid pressure cylinder for pressure equalization.

Although the air cylinder 32 is used as the movement resistance applying means in the above embodiment, the movement resistance can be applied by the relief pressure of the fluid pressure cylinder or the spring force of the spring.

Although not illustrated one by one, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating an example of a press working apparatus to which the present invention is applied.

FIG. 2 is a block diagram illustrating a control system provided in the press working apparatus of FIG.

FIG. 3 is a diagram showing the display / operation panel of FIG. 2;

FIG. 4 is a diagram illustrating a waveform of a pin transmission load in the press working apparatus of FIG.

5 is a block diagram illustrating a function of a portion that performs hydraulic control of a hydraulic cylinder for pressure equalization while performing pressure equalization diagnosis on the ON line in the press working apparatus of FIG. 1. FIG.

FIG. 6 is a flowchart illustrating an operation when performing hydraulic control of a hydraulic cylinder for pressure equalization while performing pressure equalization diagnosis on the ON line by the function of FIG. 5.

7 is a block diagram illustrating a function of a portion for diagnosing a wrinkle holding load region where a pressure equalizing state is obtained in the press working apparatus of FIG.

FIG. 8 is a flowchart illustrating an operation when diagnosing a wrinkle holding load region where a pressure equalized state is obtained by the function of FIG. 7.

[Explanation of symbols]

10: Punch type 18: Die type 22: Cushion pin 26: Cushion pad 28: Wrinkle holding ring 30: Hydraulic cylinder (fluid pressure cylinder) 40: Press material 62: Control unit 100: Pin transmission load detection device (pin transmission load detection Means) 102: Load detection mold base 104: Load detection connection pin 106: Through hole 108: Load sensor 114, 130: Data storage unit (pin transmission load detection unit) 120, 138: Pressure equalizing diagnosis unit (diagnosis unit) 122, 140: Judgment reference memory (judgment reference storage means) Steps S1 to S3: Pin transmission load detection step S5, S8: Diagnosis step Q8: Pin transmission load detection step Q10: Diagnosis step

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Chitoshi Kono 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd.

Claims (6)

[Claims] 1. A cushion pad to which a predetermined movement resistance is applied, and a plurality of cushion pins interposed in parallel between the cushion pad and the wrinkle retainer ring, the wrinkle retainer being based on the movement resistance. Wrinkles the peripheral edge of the press material between the ring and the die die, and in that state, the wrinkle retaining ring and die die together with the cushion pad resist the movement resistance in the pressing direction relative to the punch die. By being moved,
In a press working method for drawing the press material along a punch-shaped forming surface, a pin transfer load detecting step of detecting individual transfer loads of the plurality of cushion pins during the drawing, and the plurality of cushions. And a diagnosing step of judging whether or not the crease clamp is appropriate depending on whether or not a predetermined characteristic value of each transmission load of the pin satisfies a predetermined criterion. 2. A cushion pad to which a predetermined movement resistance is applied, and a plurality of fluid pressure cylinders arranged on the cushion pad and having pressure chambers communicating with each other.
A plurality of fluid pressure cylinders and a plurality of cushion pins interposed between the wrinkle holding ring and the wrinkle holding ring, and wrinkle holding the peripheral edge portion of the press material between the wrinkle holding ring and the die die based on the movement resistance. In doing so, the pistons of the plurality of fluid pressure cylinders are respectively set in a neutral state so that the wrinkle holding load is evenly applied to the wrinkle holding ring, and in this state, the wrinkle holding ring and the die type are the cushion pads. A press working method of drawing the press material along a molding surface of the punch die by moving the punch material relative to the punch die in the pressing direction together with the movement resistance. Pin transmission load detection step of detecting the individual transmission loads of the respective cushion pins, and When a predetermined characteristic value of the ultimate load satisfies a predetermined criterion, a diagnosing step of determining a pressure equalized state in which the wrinkle pressing load is evenly transmitted through each cushion pin is included. And press working method. 3. The diagnosing step determines that the pressure equalizing state is reached when a predetermined load value or a vibration frequency of the transmission loads of all the cushion pins is within a predetermined setting range, and even one of them is set. If it exceeds the range, it is judged that at least some of the fluid pressure cylinder pistons are in a cylinder thrust state, and if even one is below the set range, at least some of the fluid pressure cylinder pistons have not been activated. The press working method according to claim 2, wherein the press working method is to judge a certain non-equalized pressure state. 4. The predetermined characteristic value of the transmission load is defined to include at least one of a peak value, an average value, and a vibration frequency of a waveform of the transmission load in one drawing process. Alternatively, the pressing method described in 2. 5. A cushion pad to which a predetermined movement resistance is imparted, and a plurality of cushion pins interposed in parallel between the cushion pad and the wrinkle retainer ring, wherein the wrinkle retainer is based on the movement resistance. Wrinkles the peripheral edge of the press material between the ring and the die die, and in that state, the wrinkle retaining ring and die die together with the cushion pad resist the movement resistance in the pressing direction relative to the punch die. By being moved,
In a press working apparatus that draws the press material along the punching surface, a pin transfer load detecting unit that detects each transfer load of the plurality of cushion pins during the drawing process, and Judgment criterion storage means for storing a predetermined judgment criterion for proper wrinkle pressing with respect to a predetermined characteristic value, and transmission of each of the plurality of cushion pins detected by the pin transmission load detection means. A press working apparatus, comprising: a diagnosing means for judging whether or not the crease presser is appropriate depending on whether or not a predetermined characteristic value of the load satisfies the judgment standard stored in the judgment standard storage means. 6. The cushion pad is lowered in a substantially horizontal posture against the movement resistance, and the punch type is positioned and fixed on a bolster arranged above the cushion pad. The plurality of cushion pins are placed on the cushion pad by penetrating through a through hole provided vertically penetrating the punch type and the bolster, and support the wrinkle holding ring at the upper end portion. The press working apparatus according to claim 5, wherein the pin transmission load detection device is used as the pin transmission load detection means, and is inserted between the bolster and the punch die.
A load detection mold base provided with a through hole that allows the cushion pin to vertically pass therethrough, and the plurality of cushion pins having substantially the same length as the height of the load detection mold base. And a plurality of load detecting connecting pins to which a load sensor for detecting the transfer load of the cushion pin is attached.