WO1992022392A1

WO1992022392A1 - Die cushion pin pressure equalizing system, method of calculating peak oil pressure in the system and method of calculating service life of pressure equalizing hydraulic cylinders

Info

Publication number: WO1992022392A1
Application number: PCT/JP1992/000776
Authority: WO
Inventors: Nobuyuki Kaji
Original assignee: Kabushiki Kaisha Komatsu Seisakusho
Priority date: 1991-06-17
Filing date: 1992-06-17
Publication date: 1992-12-23
Also published as: DE4291861T1; JPH04371324A; JP3062665B2

Abstract

In a die cushion pin pressure equalizing system wherein a plurality of die cushion pins are provided in the bolster of a press machine, pressure equalizing hydraulic cylinders supported by die cushions are respectively provided downwardly of the plurality of die cushions and the plurality of pressure equalizing hydraulic cylinders are connected to one another, so that a predetermined oil pressure is sealed therebetween, a total amount of oil sealed in the die cushion pin pressure equalizing system is increased to thereby easily prevent stopper portions of plungers of unused pressure equalizing hydraulic cylinders from filing, cracking, breaking and oil leaking.

Description

Technical field of calculating the beak bubble pressure and the equalizing hydraulic cylinder life of a dik s bin bin pressure equalizer and same beard

The present invention provides an improvement for preventing breakage and oil leakage of a pressure equalizing hydraulic cylinder of a die cushion pin pressure equalizing device used for drawing, and calculates a peak hydraulic pressure to be obtained in order to perform the preventive measures. For how to.

Background technology

In the press machine, a die cushion is provided below the lower die to prevent wrinkles from occurring during the drawing press.

That is, Fig. 6 shows a press machine equipped with a die, 1 is a crown, 2 is an ablate, 3 is a bed, 4 is a slide, 5 is an upper mold, 6 is a lower mold, and 7 is a lower mold. Bolster, 8 is a moving bolster, 9 is a cushion pin, 10 is a pressure equalizing device plate, 11 is an equalizing hydraulic cylinder, 12 is a die cushion pad, 13 is a die cushion leg, and 14 is a die cushion leg. A cushion wheel cylinder, numeral 15 is a cushion rod, and numeral 16 is a damper filled with oil.

That is, in FIG. 6, a bolster 7 is installed on a bed 3 via a moving bolster 8, and a die cushion pad I 2 is accommodated in the bed 3. The die cushion pad 12 is supported by a die cushion cylinder 14 provided on a cushion leg 13. The compressed air source is connected to the suction cylinder 14 via a pressure adjusting unit (not shown).

A lower die 6 is mounted on the bolster 7, and a plurality of die cushion pins 9 are provided in the bolster 7 so as to pass through a plurality of pin holes. The plurality of da I cushion pins 9 Ru Tsutere, such to support a Daipa' de (not shown) in the lower die 6 ₀

Further, a plurality of pressure equalizing hydraulic cylinders 11 are provided on the pressure equalizing device plate 10 corresponding to the positions of the plurality of cushion pins 9. As shown in Fig. 7, the plunger 18 comes into contact with the lower end of the cushion pin 9 and the flange 17 of the plunger 18 comes into contact with the cylinder oil chamber. Is housed in That is, the flange portion 17 of the plunger functions as a stopper above the cylinder 11.

Each cylinder oil chamber of the equalizing hydraulic cylinder 11 is connected to a hydraulic source (not shown) via an oil passage 19 (a borehole, a pipe, etc. provided in the equalizing device plate 10). I have. A check valve is provided in the oil passage 19, and oil adjusted to a pressure sufficient to absorb the length ^ of each cushion pin is sealed in the oil passage 19 and each cylinder oil chamber. .

Therefore, when drawing, the die cushion pin is selected according to the die, and then the press machine is driven. When the force D pressure is applied to the die cushion pin 9 to be used, the hydraulic pressure supplied to each pressure equalizing hydraulic cylinder 11 is leaked, so the force D pressure is reduced to the cushion pin 9 and the hydraulic cylinder 1 By being transmitted to the die cushion pad 12 via 1, it is absorbed by the die cushion cylinder 14. At the same time, the non-uniformity of the force 0 pressure due to the length error of each die cushion pin 9 and the error at the time of mounting is absorbed by the cushion pressure of the equalizing hydraulic cylinder 11 described above.

By the way, in the die mining pin equalizing device composed of the plurality of equalizing hydraulic cylinders 11 and the like, ¾¾, operating conditions (the diameter of the plunger 18 of the equalizing hydraulic cylinder 11, the number of pins used, Since the molding was performed without accurately considering the speed at which the mold touches the die cushion pin, the total amount of oil filled in the pressure equalizing device, and the air pressure at the time of pin touching. Not used (not selected) Equalizing hydraulic cylinder 11 A plunger flange 17 of 11 has a fatigue cracking destructive force as shown in Fig. 8 or an oil leak force from hydraulic cylinder 11 There was a problem of running. The reason for this time breath driving, the die cushion pins 9 to the plunger 1 8 of the pressure-equalizing hydraulic cylinders and through the load ^force? Consuming, the load is not used over the oil in the oil passage 1 9 Plunger 1 8 is considered to be the main cause of the peak hydraulic pressure, especially when the die touches the die cushion pin 9 among the above-mentioned loads.

As a means to solve the above problem, it is conceivable to provide an accumulator in the hydraulic circuit of the pressure equalizer, but the peak hydraulic pressure time is about 0.05. If the accumulator is not disposed in the vicinity of the pressure equalizing device because the time is short, there is a problem that a peak occurs before the pressure wave reaches the accumulator. However, it is impossible to dispose the accumulator in the immediate vicinity of the pressure equalizing device, considering the problem of interference with the mold.

Further, as another means, it is conceivable to attach a cushioning material such as urethane rubber to the upper end or the lower part of the die cushion pin 9, which is problematic in terms of durability and a substantial peak reduction effect.

Also, when investigating the cause of the fatigue ft crack fracture of the plunger, the fatigue life of the plunger was obtained by calculation or the like, but there was a problem that the calculated life did not match the actual life. It is considered that the reason for this was that the oil pressure value at the maximum operating SPM (SPM: number of continuous strokes: the number of strokes per minute) was set to be much lower than the actual oil pressure. Therefore, a method for accurately calculating the peak oil pressure has been desired.

The present invention has been made in view of such circumstances, and has a die cushion pin pressure equalizing device capable of easily preventing fatigue of a flange portion of a plunger of an unused pressure equalizing hydraulic cylinder and fracture or oil leakage. The purpose is to provide.

It is another object of the present invention to provide a method of calculating a peak oil pressure of a die cushion pin pressure equalizing device, which can accurately determine an actually generated peak oil pressure.

Disclosure of the invention

According to the present invention, a plurality of die cushion pins are provided in a bolster of a press machine, and a pressure equalizing hydraulic cylinder supported by a die cushion is provided below each of the plurality of die cushion pins. In a die cushion pin pressure equalizing device in which hydraulic cylinders are connected to each other to seal a predetermined oil pressure, the total amount of oil sealed in the die cushion pin pressure equalizing device is increased. To

That is, by increasing the total amount of oil to be filled in the pressure equalizing device, the shock force applied to the unused hydraulic cylinder is reduced;-the primary peak pressure is reduced, and The life of pressure equalizing hydraulic cylinder can be extended o Thus, according to this method, the simple measure of increasing the total amount of oil in the pressure equalizing device can only be used to reduce the fatigue of the stopper of the plunger of the unused pressure equalizing hydraulic cylinder. Breakage and oil leaks can be reliably and easily prevented, thereby greatly extending the life of the plunger.

According to the present invention, a plurality of die cushion pins are provided in a bolster of a press machine, and a pressure equalizing hydraulic cylinder supported by a die cushion is provided below each of the plurality of die cushion pins. Die cushion pin for calculating the peak hydraulic pressure generated in the pressure equalizing hydraulic cylinder of the die cushion pin pressure equalizing device in which the pressure equalizing hydraulic cylinders are filled with a predetermined hydraulic pressure. In the hydraulic pressure calculation method, the temporary primary peak pressure is calculated based on the diameter of the plunger of the hydraulic cylinder with a reduced pressure, the number of die cushion pins used, and the speed of the upper die when the upper die contacts the die cushion pins. A first step of calculating; a second step of correcting the provisional primary peak pressure obtained in the first step with a total oil amount value in the 2nd pressure diversion apparatus; The Tadashisa hydraulic pressure value corrected by the die cushion air pressure, so as comprise a third step of obtaining the first peak pressure.

Therefore, according to the present invention, it is possible to accurately obtain the peak hydraulic pressure that actually occurs in the die cushion pin pressure equalizing device.

Brief explanation of drawings

FIG. 1 is a flowchart showing a procedure for calculating a peak hydraulic pressure according to the present invention, FIG. 2 is a graph showing a hydraulic waveform generated in a die cushion pressure equalizing device, and FIG. 3 is a diagram for calculating a temporary primary peak hydraulic pressure. Graph, Fig. 4 is a graph for correction by die cushion air pressure, Fig. 5 is a graph for obtaining secondary peak oil pressure from primary peak oil pressure, and Fig. 6 is a die cushion pin pressure equalizing device. Fig. 7 shows a press machine equipped with a pressure equalizer, Fig. 7 is an enlarged view of the hydraulic cylinder part of the pressure equalizing device, and Fig. 8 shows the fatigue of the plunger of the pressure equalizing hydraulic cylinder plunger. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, a detailed description will be given of the force f in which the above-mentioned shimmer is made into an embodiment shown in the accompanying drawings.

Fig. 2 shows the hydraulic pressure waveform of the die cushion pin pressure equalizing device shown in Figs. 6 and 7 above, where 0 is the preload hydraulic pressure, Pmaxl is the pin touch time (the upper die 5 is (When touching the cushion pin 9), the primary peak hydraulic pressure, Pmax2 is the secondary peak hydraulic pressure, and PD is the stable hydraulic pressure according to the capacity of the die cushion.

Fig. 1 shows the procedure for calculating the primary peak hydraulic pressure Pmaxl and the secondary peak hydraulic pressure Pmax2 and the procedure for calculating the fatigue damage of the plunger: ^ life, as shown in Fig. 2 above. Explanation will be given according to the

In the calculation method jl, the following five parameters are used as the calculation parameters.

• Plunger 18 diameter? Five,

'Number of die cushion pins 9 to be used N,

• Pinch speed V

• The total oil quantity Q of the oil enclosed in the pressure equalizer,

'' Die cushion air pressure p

• Procedure 1… Calculation of temporary primary peak pressure Pa (Step 100)

First, the diameter of the plunger 18? ! Then, the number N of the die cushion pins 9 to be used and the pinching speed V are obtained, and based on these values, the temporary primary peak pressure Pa is calculated using the corresponding graph in FIG.

In other words, the graph in Fig. 3 shows the number of die cushion pins used (N) on the horizontal axis, and changes the scale of the graph between this number N and 6 O mm when the plunger diameter is 5 In addition, the right vertical axis plots the pin-touch speed V (m / sec), and the left vertical axis plots the temporary primary peak pressure Pa (kg / cm2). In FIG. 3, the plotted point “-” indicates an actual measurement value at a certain factory, and the other plot point “〇” indicates an actual measurement value at another factory. For example, if a plunger diameter? 5 of 5 O mm is used, the number of these used is 15 and the pin touch speed V is 0.6 m / sec, the temporary primary peak pressure P in this case is P a becomes 530 kg / cra2. In other words, a vertical line plotting the number of pins used and a line plotting the pin touch speed (the three lines shown in Fig. 3 indicate that the pin touch speed is 0.43 m / sec, 0.59 m / sec, At 0.76 m / sec, and draw a line corresponding to the pin touch speed at that time with reference to these three lines). Is the temporary primary peak pressure Pa at this time. This Fig. 3 The graph shows that the temporary primary peak pressure Pa can be obtained when the total oil quantity Q of the oil enclosed in the pressure equalizer is 6.1 liters and the diction air pressure p is 6.2 kg / cm2. When the total oil amount Q and die cushion air pressure p are different from the above values, the correction calculation is performed according to the following procedure.

However, when the diameter of the plunger is 5 mm and the number of die cushion pins for officials N is 40 mi, or when the diameter of the plunger is 5 and the number of die cushion pins N is 58, It is not necessary to perform the correction calculation for the total oil amount Q and the die cushion air pressure P described above.

'Procedure 2… Correction based on total oil amount of pressure equalizer (Step 1 10)

Next, the calculated primary peak pressure Pa is corrected by the total oil amount Q (liter) of the pressure equalizing device to obtain a calculated primary peak pressure: Pb. One of the following two equations (1) and (2) is used as the correction equation used in this case. As described above, the number of die cushion pins used when the diameter of the plunger? 5 is 50 and the number of die cushion pins used is 40 or more when the plunger diameter? 5 is 60 mm. When the value is 58: Lh, it is not necessary to perform this step 2, that is, the correction calculation based on the total oil amount Q.

If the number N of die cushion pins used is 10≤N <27 (however, 5 Oram) or 1 5≤N <39 (where = 6 Oran),

Pb = PaX (6.1 / Q). -s

...

When the number N of die cushion pins used is 27≤N <40 (5? 50mm) or 3 9≤N <58 (5? 60mm)

Pb = PaX (6.1 / Q). -. '-

… (2)

For example, a plunger diameter of 50mm? If the number of these used is 15 and the pinching speed V is 0.6 ra / sec, and the total oil amount Q of the pressure equalizer is 5.◦ liter, In step 1 above, the temporary primary peak pressure Pa was assumed to be 530 kg / cm2. Substituting this into the above equation (1) to calculate, the calculated primary peak pressure Pb is Pb = 53 OX (6.1 / 5. 0). 's

= 634 kg / cm2

Becomes

'Handle 3 ... Correction calculation using die cushion air pressure p (step 120) Next, the calculated primary peak pressure Pb calculated in step 2 above is corrected using die cushion air pressure p, and the final Obtain the primary peak pressure Pmaxl.

For this hand I3, (a graph showing the correspondence between the die cushion air pressure and the primary peak pressure in FIG. 4 is used. In FIG. 4, the plotted point "·" Shows actual measured values at the factory.

In other words, in this time j, a line extending horizontally on the vertical axis corresponding to the calculated primary peak pressure Pb calculated in step 2 above and a fiber corresponding to the die cushion air pressure p = 6.2 kg / cm2 Find the intersection with the fountain and plot parallel lines that pass through this intersection and along the multiple lines shown in Figure 4. The value obtained by extending the intersection of the plotted line and the desired air pressure to the left to the left is defined as the primary peak pressure Pmax.

For example, 50 plunger diameter? 5 and the number of these used is 15 • Assume that the pin touch speed V is 0.6 m / sec, the total oil amount Q of the pressure equalizer is 5.0 liters, and the die cushion Assuming that the air pressure p is 3.0 kg / cm2, the primary peak pressure Pa calculated through the above manual MI 1 and step 2 is calculated as 634 kg / cm2, so this calculated primary peak pressure Pa == 634 kg / cm2 and die cushion air pressure p = 3.0 ■ By using kg / cm2 and the graph in Fig. 4, the primary peak pressure Pmax = 590 kg / cm2 can be obtained.

'Affordable 4-' 'secondary peak pressure? 111 2> Correction for primary peak pressure Pmaxl (Step

1 30)

When the number of die cushion pins used is small and the air pressure of the die cushion is high, the secondary peak pressure P x2> may be the primary peak pressure Pmaxl. Use the value of the secondary peak pressure Pmax2 instead of the secondary peak pressure Pmaxl.

Figure 5 shows the calculation of the secondary peak pressure Pmax2 from the primary peak pressure Pmaxl calculated in step 3. The graph shows the number of die cushion pins used (N) on the horizontal axis, and this number N is used when the plunger diameter? 5 is 5 Omm and 6 Omm. The scale is changed, and the right vertical axis plots the die cushion air pressure P (kg / cm ² ), and the left vertical axis plots the ratio of the secondary peak pressure Pmax x2 to the primary peak pressure Praaxl. ing. In FIG. 5, the plotted point “-” indicates an actual measurement value at a certain factory.

In other words, the fine spring with the number of pins for the officer and the line with the die cushion air pressure plotted (the six lines shown in Fig. 5 show the die cushion air pressure of 1.5 kg / cm ² and 2 kg). / cm ² , 3 kg / cm ² , 4 kg / cm ² , 5 kg / cm ² , and 6 kg / cm ² , and these six lines correspond to the die cushion air pressure at that time. The value at the position where the intersection point of is extended to the left is the ratio (Pmax2 / Pmaxl) of the secondary peak pressure Pmax2 to the primary peak pressure Proaxl at this time.

When this ratio is larger than 1, the secondary peak pressure Pmax2 is calculated by multiplying the primary peak pressure Pmaxl calculated in the previous step 3 by this ratio, and the secondary peak pressure Pmax2 is calculated in the subsequent life calculation. Beak pressure Pniax2 should be used.

'Procedure 5… Plunger stress calculation (Step I 40)

In addition to the peak pressure Pmaxl or Pmax2 calculated above, the hydraulic pressure area, load, gage moment, If surface coefficient, shear area, bending stress, shear stress, and stress concentration rate are obtained, and the plunger of Calculate the maximum principal stress and i (kg / mra2) generated at the stopper for each die used in the press machine.

'Procedure 6: Calculation of fatigue fracture life of plunger (Step 150)

Next, by substituting the obtained maximum stress i for each mold into the following equation (3), the fatigue fracture: ^ life (year) is calculated.

Fatigue life L (years) = D0 / Dy

= D0 / Pi i ⁴ * Ni

… (3)

DO: Allowable fatigue damage (fixed value)

Dy: Annual fatigue damage

And i: Kishi raw stress for each mold used Ni: Number of annual loads for each mold used (fixed value)

i; mold unit

In this way, the plunger's fatigue breach is calculated.

The fatigue failure life L obtained by such a method was able to obtain a favorable agreement with the life of the actually destroyed plunger.

By the way, as is clear from the above discussion, the life L of the stopper portion of the plunger can be extended by lowering the primary peak pressure P maxl.

Here, when focusing on the equations (1) and (2) shown in the previous step 2, since the total oil amount Q of the equalizer is present in the denominator of the above equations (1) and (2), Primary peak pressure: The value of Pira xl can be reduced by increasing the total oil amount Q compared to the conventional one. That is, by increasing the total oil amount Q of the pressure equalizing device, the primary peak pressure applied to the unused pressure equalizing hydraulic cylinder is reduced (dulled), whereby the life of the pressure equalizing hydraulic cylinder is reduced. To extend.

Therefore, in the present apparatus, the life of the pressure equalizing hydraulic cylinder is extended by using a simple method of increasing the total oil amount Q of the pressure equalizing device. The parameter of the total oil amount Q of the pressure equalizing device is a parameter that can be adjusted more easily than other parameters such as the number of used die cushion pins, die cushion air pressure, and pin touch speed. .

In other words, changing the number of die cushion pins involves difficulties ⁵ 'when considering the correspondence with the mold, and changing the die cushion air pressure is likely to generate molding failure force ^s. This is not possible, and if the pinching speed is further changed (reduced), the production capacity per hour s decreases, and there is a problem that the producers are not readily accepted.

The above procedure of calculating peak pressure as described in the examples which are exemplary force ^§ course possible fully automatically by the software of.

Industrial applicability

INDUSTRIAL APPLICABILITY The present invention is useful for a technique in which a die cushion pin equalizing device is attached to a press machine to perform a drawing force D.

Claims

The scope of the claims

1. A plurality of die cushion pins are provided in the bolster of the press machine, and a pressure equalizing hydraulic cylinder supported by a die cushion is provided below each of the plurality of die cushion pins. Hydraulic cylinders are connected to each other by oil passages, and a predetermined pressure is filled in these hydraulic cylinders and oil passages.

A die cushion pin pressure equalizing device, wherein the total oil amount of the oil sealed in the die cushion pin pressure equalizing device is increased.

2. A plurality of die cushion pins are provided in the bolster of the press machine, and a pressurized hydraulic cylinder supported by a die cushion is provided below each of the plurality of die cushion pins to equalize the plurality of pressure equalization. Hydraulic cylinders are mutually connected by oil passages, and peak equalization occurring in the equalizing hydraulic cylinders of the die cushion pin equalizing device in which a predetermined oil pressure is sealed in these equalizing hydraulic cylinders and the oil passages. In the method of calculating the peak hydraulic pressure of the die cushion pin equalizing device for calculating the pressure, the diameter of the plunger of the pressurized hydraulic cylinder, the number of die cushion pins to be used, and the upper die when the upper die contacts the die cushion pin A first step of determining a temporary primary peak pressure based on the speed;

A second step of correcting the provisional primary peak pressure determined in the first step with the total oil amount value in the pressure equalizing device;

In the second step, the corrected peak pressure value is corrected by the die cushion pressure to obtain a primary peak pressure, and a third step is performed.

A method for calculating the peak hydraulic pressure of a die cushion pin pressure equalizing device comprising:

3. In the second step, the diameter of the plunger of the pressure equalizing hydraulic cylinder 5 is 50 and the number of die cushion pins N to be used at 50 thighs is 1 Ο ^ Ν <2 7 (however, ί = 50 删). ) Or when the plunger diameter of the pressure equalizing hydraulic cylinder is 6 Oran and the number of die cushion pins N to be used is 15 ≤ N and 39, the temporary primary peak is calculated according to the following formula. To correct the pressure P a Pb = PaX (6.1 / Q) ° ⁹

Pb: Temporary primary peak pressure after correction

Q: Total oil value

When the plunger diameter of the pressure equalizing hydraulic cylinder is 5 Omm and the number N of cushion pins to be used is 27 ≤ N <40 (however, 5 = 50 圆), or plan for a pressure equalizing hydraulic cylinder 3. The die cushion pin according to claim 2, wherein the temporary primary peak pressure Pa is corrected according to the following equation when the jar diameter is 60 and the number of die cushion pins N to be used is 39 ≤N <58. Calculation method of peak oil pressure of pressure equalizing device.

Pb = P aX (6.1 / Q) °-. -4. A plurality of die cushion pins are provided in the bolster of the press machine, and a pressure equalizing hydraulic cylinder supported by a die cushion is provided below each of the plurality of die cushion pins. The life of the pressure equalizing hydraulic cylinder of the die cushion pin pressure equalizing device, in which the pressure equalizing hydraulic cylinders are connected to each other by an oil passage so that a predetermined oil pressure is filled in the oil equalizing hydraulic cylinder and the oil passage, is provided. In the method for calculating the life of the equalizing hydraulic cylinder of the cushioning equalizing device,

A first step of calculating a temporary primary peak pressure based on the plunger diameter of the equalizing hydraulic cylinder, the number of die cushion pins used, and the speed of the upper die when the upper die contacts the die cushion pins; ,

A second step of correcting the temporary I-order peak pressure obtained in the step I with a total oil amount value in the pressure equalizing device;

A third step of correcting the peak pressure value corrected in the second step with a die cushion air pressure to obtain an I-order peak pressure;

The secondary peak pressure is calculated based on the obtained I-order peak pressure, the plunger diameter of the equalizing hydraulic cylinder, the number of die cushion pins to be used, and the speed of the upper die when the upper die contacts the die cushion pins. The fourth step,

If the ratio of the secondary peak pressure to the primary peak pressure is less than or equal to I, select the secondary peak pressure.If the ratio is greater than I, select the secondary peak pressure. Hydraulic area of jar, load on plunger, bending mode of plunger , The plunger section modulus, the plunger shear area, the plunger bending stress, the plunger shear stress, and the plunger stress concentration rate. A fifth step of determining the stress, and a sixth step of determining the fatigue fracture life of the plunger of each pressure equalizing hydraulic cylinder using the determined maximum principal stress.

Method for calculating the life of a hydraulic cylinder for pressure equalization of a die cushion pin pressure equalizer equipped with: 5. In the sixth step, assuming that the maximum stress is applied, the allowable fatigue damage is D0, and the annual number of loads on the mold is N, the fatigue fracture life years L is calculated according to the following equation. A method for calculating the life of a pressure equalizing hydraulic cylinder of a die cushion pin pressure equalizing apparatus according to claim 5, characterized in that:

L = D0 / Pi i 'Ni i; Mold unit