JP2014144470A - Press machine and slide control method of press machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press machine capable of improving press moldability, by adding large pressurization force to a metal mold, and imparting smooth vibration only in the direct advance direction.SOLUTION: A slide is constituted of a main slide 24 and a sub-slide 26, and a cylinder-piston mechanism is constituted, and the pressurization force is transmitted to the sub-slide 26 (an upper die 31a) via hydraulic pressure pressurized by interlocking with driving of the main slide 24 in press molding, and the sub-slide 26 is also vibrated by periodically changing the hydraulic pressure. Excellent press molding is executed even under a condition of comparatively difficult press molding by controlling vibration so that a frequency of the vibration of the sub-slide 26 (the upper die 31a) becomes 9 Hz-33.3 Hz and a vibration width becomes 0.05 mm-0.5 mm.

Description

  The present invention relates to a press machine and a slide control method of the press machine, and more particularly to a technique for forming a material while giving a minute vibration to a mold.

  Conventionally, there has been proposed a press vibration molding method in which a vibrator is connected to an upper die of a press machine, the upper die is lowered while being ultrasonically vibrated by the vibrator, and a material is pressed with the lower die (patent) Reference 1).

  In addition, a vibration processing device that transmits vibration to the press head by a lever mechanism, and a press molding device in which a vibration mechanism having a cam portion is inserted at an intermediate rotation fulcrum of a link mechanism that drives a slide have been proposed (Patent Document 2). 3).

  Furthermore, a press machine (Patent Documents 4 and 5) that vibrates a slide with a servo motor that indirectly drives a crankshaft via a gear or the like, a press that directly excites a slide with a linear servo motor (Patent Document 6), In a press machine that uses a servo motor to drive a slide using a screw nut mechanism without using a speed reducer, there has been proposed one that applies high-frequency vibration in which the screw nut mechanism is finely moved (Patent Document 7).

JP-A-1-122624 JP-A-9-285896 JP 2008-260042 A JP 2011-16138 A JP 2011-245515 A JP 11-77389 A Japanese Patent Application Laid-Open No. 11-151631

  According to the invention described in Patent Document 1, the press machine manufacturing side performs press molding while applying micro-vibration to the mold against the background when the technology for freely operating the slide has not been established. Therefore, it is considered that the mold structure of the embodiment in which the ultrasonic vibrator is connected to the mold (upper mold) is forced. In this case, a vibration mechanism is provided for each mold, and there is a problem that the price is extremely increased.

  The inventions described in Patent Documents 2 and 3 do not vibrate the slide that is vertically moved up and down in the vertical direction, and a vibration component other than the vertical direction due to vibration is applied to the slide. For this reason, the slide moves in a direction other than the vertical direction due to the give gap or the shaft gap (with slight movement for the gap). In addition to the advantage of reducing the friction between the mold and the material, this action is dominated by the drawback of imparting resistance that hinders molding between the two, and the action of improving the moldability cannot be obtained.

  The inventions described in Patent Documents 4 and 5 increase the frequency due to an increase in the inertial mass of the slide to be vibrated, the backlash of the gear, and the vertical and horizontal gaps at various locations in the mechanism. It is difficult to improve the moldability, and the vibration waveform is irregular, which is considered unsuitable for improving the moldability, and its purpose of use is limited to preventing sticking of the slide. In addition, since there is a concern of damaging the mechanism itself, it is difficult to implement in a molding application (application for friction reduction).

  In the invention described in Patent Document 6, since the slide is directly vibrated by the linear servo motor, the magnitude of the output is limited. For example, the magnitude of the force and energy is limited to less than about 100 kW and less than about 20 kW. For this reason, the object to be molded is limited, and it is impossible to apply it to a press machine.

  Since the invention described in Patent Document 7 applies vibration in the rotational direction via the screw nut mechanism, the slide vibrates not only in the vertical direction but also in the rotational (torsional) direction. There is a problem that the vibration is easily generated and molding is easily inhibited.

  The present invention has been made in view of such circumstances, and can apply a large pressing force to the mold and can provide a smooth vibration to the mold only in the straight direction in which pressure is applied. It is an object of the present invention to provide a press machine and a slide control method for the press machine that can improve press formability.

  In order to achieve the above object, a press machine according to an aspect of the present invention includes a main slide disposed so as to be reciprocally movable in a rectilinear direction, main slide drive means for reciprocatingly driving the main slide, and a die. A sub-slide that is mounted so as to be reciprocally movable in the same direction as the main slide, and to which the applied pressure applied to the main slide is transmitted via hydraulic pressure, and the main slide Sub-slide drive means for reciprocally driving the sub-slide, wherein the sub-slide drive means is configured to reciprocate the sub-slide in the same direction as the main slide by changing the hydraulic pressure, Vibration control means for controlling the sub slide drive means so that the sub slide vibrates, and the main slide drive hand Shaping the material in cooperation with the sub-slide driving means and.

  According to one aspect of the present invention, the slide is constituted by the main slide and the sub slide to which the mold is mounted, and the slide (the main slide and the sub slide) is reciprocated in the straight direction by the main slide driving means. Because the sub slide is reciprocated (vibrated) relative to the main slide by the sub slide drive means, the inertial mass of the sub slide to be vibrated can be reduced, and the variable speed response of the vibrating mold can be improved. Can be made. In addition, since the sub slide is disposed so as to be able to reciprocate in the same direction as the straight direction in which the main slide reciprocates, the mold can be vibrated only in the straight direction in which the material is pressurized. Due to the friction-reducing action, the press formability can be improved (breakage and cracking of the material being formed can be prevented). Furthermore, since the pressure applied to the main slide from the main slide driving means is transmitted to the sub slide via the hydraulic pressure, a large pressure can be applied to the sub slide (mold), and the main slide and sub Since no mechanical transmission element is interposed between the slide and the slide, the sub-slide can be vibrated smoothly without being affected by a mechanical gap or the like.

  In the press machine according to another aspect of the present invention, the vibration control means has a vibration frequency of the sub-slide of 9 Hz to 33.3 Hz and a vibration width of the sub-slide of 0.05 mm to 0.5 mm. It is preferable to control the sub-slide driving means so as to be as follows. It was discovered that there are cases where press molding succeeds and fails depending on the vibration conditions (vibration frequency and vibration width) of the mold, and vibration conditions under which press molding succeeds have been found from vibration experimental results. That is, when performing press molding, the mold (sub-slide) is vibrated so that the frequency of vibration applied to the mold is 9 Hz to 33.3 Hz and the vibration width is 0.05 mm to 0.5 mm. Is preferred.

  In the press machine according to still another aspect of the present invention, the vibration control means has a vibration frequency of the sub-slide of 11.6 Hz to 33.3 Hz and a vibration width of the sub-slide of 0.05 mm or more. The sub-slide driving means is controlled to be 0.5 mm or less, or the vibration frequency of the sub-slide is 0.8 Hz or more and less than 11.6 Hz, and the vibration width of the sub-slide is 0.04 mm or more, It is preferable to control the sub-slide driving means so that the speed direction during the molding of the sub-slide is not more than a value that does not reverse.

  By vibrating the mold (sub-slide) so that the vibration frequency of the mold is 11.6 Hz to 33.3 Hz and the vibration width is 0.05 mm to 0.5 mm, It has been found from the experimental results of vibration that the limit drawing ratio increases due to the friction reducing action during the period. Further, by vibrating the mold (sub-slide) so that the frequency is 0.8 Hz or more and less than 11.6 Hz, the vibration width is 0.04 mm or more, and a value that does not reverse the speed direction during molding, the material is obtained. It was found from the experimental results of vibration that the limit drawing ratio increases due to the stress relaxation action of.

  In the press machine according to still another aspect of the present invention, the vibration control means includes a relative position command means for outputting a relative position command signal indicating a relative position of the sub slide with respect to the main slide, and the main slide. Relative position detection means for detecting a relative position of the sub-slide with respect to and outputting a relative position detection signal indicating the detected relative position; and a relative position command signal output from the relative position command means; It is preferable to control the sub-slide drive unit based on a relative position detection signal output from the relative position detection unit. That is, when a vibration is applied to the mold during molding, the relative position of the sub-slide (the position in the straight direction corresponding to the vibration waveform) is controlled with respect to the main slide that is moving in the straight direction. The position of the sub slide (die) is controlled by the position and the relative position of the sub slide with respect to the main slide.

  The press machine which concerns on the further another aspect of this invention WHEREIN: The position command device which outputs the position command signal which shows the position of the said sub slide on the basis of the said main slide, The frequency and vibration width of the vibration of the said sub slide are shown. A vibration command device that outputs a vibration command signal, and the relative position command means adds the vibration command signal output from the vibration command device to the position command signal output from the position command device, and A relative position command signal is output.

  The position command signal output from the position commander is a signal for controlling the relative position of the sub slide so that the slide motion of the sub slide becomes a desired slide motion (a slide motion different from the slide motion of the main slide). The relative position command signal obtained by adding a vibration command signal to this position command signal vibrates the sub slide in an appropriate period or the like while controlling the relative position so that the sub slide has a desired slide motion. It is used as a signal for

  In the press machine according to still another aspect of the present invention, the main slide and the sub-slide constitute a cylinder-piston mechanism, and the main slide is one of a cylinder and a piston of the cylinder-piston mechanism. The sub-slide is the other of the cylinder and the piston of the cylinder-piston mechanism. Thereby, the applied pressure applied to the main slide is transmitted to the sub slide via the hydraulic fluid in the cylinder-piston mechanism, and the hydraulic pressure of the hydraulic fluid in the cylinder-piston mechanism is controlled separately. Vibration or the like can be applied to the slide.

  In the press machine according to still another aspect of the present invention, the sub-slide drive means includes a servo motor and a hydraulic pump / drive driven by the servo motor to supply pressurized fluid to the hydraulic chamber of the cylinder-piston mechanism. And a motor.

  In the press machine according to still another aspect of the present invention, the main slide drive means continuously moves the main slide through a connecting rod of the press machine for at least a molding period.

  A slide control method for a press machine according to still another aspect of the present invention includes a main slide disposed so as to be capable of reciprocating in a rectilinear direction, and a sub-slide to which a mold is mounted, the same direction as the main slide. And a sub-slidably disposed sub-slide in the press machine, the main slide is driven in the straight direction, and the sub-slide is driven in the straight direction in conjunction with the drive of the main slide. A step of transmitting an applied pressure to the sub-slide via a hydraulic pressure that is pressurized in conjunction with the driving of the main slide during molding, and periodically changing the hydraulic pressure during molding of the material And oscillating the sub-slide.

  In the slide control method for a press machine according to still another aspect of the present invention, the vibration of the sub-slide is set to have a vibration width and frequency that reduce friction of the sliding surface between the material and the mold. It is preferable.

  In the slide control method for a press machine according to still another aspect of the present invention, the vibration of the sub-slide is such that the vibration frequency of the sub-slide is 9 Hz or more and 33.3 Hz or less, and the vibration width of the sub-slide is 0. It is preferably set to be from 05 mm to 0.5 mm.

  In the slide control method for a press machine according to still another aspect of the present invention, the vibration of the sub-slide is such that the vibration frequency of the sub-slide is 11.6 Hz to 33.3 Hz, and the vibration width of the sub-slide is The sub-slide is set to be 0.05 mm or more and 0.5 mm or less, or the vibration frequency of the sub-slide is 0.8 Hz or more and less than 11.6 Hz, and the vibration width of the sub-slide is 0.04 mm or more. It is preferable that the speed direction during molding is set to a value that does not reverse the direction.

  According to the present invention, the slide is constituted by the main slide disposed so as to be reciprocally movable in the straight direction and the sub slide disposed so as to be reciprocally movable in the same direction as the main slide, and the main slide is formed during press molding. Because the pressure is transmitted to the sub-slide through the hydraulic pressure that is pressurized in conjunction with the drive of the sub-slide, and the sub-slide is vibrated by periodically changing the hydraulic pressure, the sub-slide (mold) ), And a mechanical transmission element is not interposed between the main slide and the sub-slide, so that there is no influence due to a mechanical gap or the like, and it can be vibrated smoothly. In addition, since the sub-slide is reciprocated (vibrated) relative to the main slide, the inertial mass of the sub-slide to be vibrated can be reduced, energy required for vibration can be reduced, The variable speed response of the mold can be greatly improved.

  Further, the mold and the material are controlled by controlling the vibration of the mold so that the vibration frequency of the sub-slide (mold) is 9 Hz or more and 33.3 Hz or less and the vibration width is 0.05 mm or more and 0.5 mm or less. The limit drawing ratio can be increased by the friction reducing action between the two, and good press molding can be performed even under relatively difficult press molding conditions.

The block diagram which shows embodiment of the press machine to which this invention is applied The block diagram which shows embodiment of the sub slide controller which controls the sub slide of the press machine shown in FIG. Diagram showing how material is formed (drawn) by upper die (die) and lower die (punch) Waveform diagram showing the sub-slide position, press load, and sub-slide relative position in the drawing process when the press machine is operated under the operating condition (1) Waveform diagram showing the sub-slide position, press load, and sub-slide relative position in the drawing process when the press machine is operated under the operating condition (2) Waveform diagram showing sub-slide position, sub-slide relative position, sub-slide speed, and press load (sub-slide load) in the drawing process when the press machine is operated under the operating condition (3) Waveform diagram showing sub-slide position, sub-slide relative position, sub-slide speed, and press load (sub-slide load) in the drawing process when the press machine is operated under the operating condition (4) Waveform diagram showing sub-slide position, sub-slide relative position, sub-slide speed, and press load (sub-slide load) in the drawing process when the press machine is operated under the operating condition (5) Graph showing the correlation result of sub-slide frequency-vibration width when the material is completed without breaking, based on the experimental drawing results Block diagram showing an embodiment of a relative position commander

  Hereinafter, preferred embodiments of a press machine and a slide control method of the press machine according to the present invention will be described in detail with reference to the accompanying drawings.

[Embodiment of press machine]
<Structure of press machine>
FIG. 1 is a configuration diagram showing an embodiment of a press machine to which the present invention is applied.

  A press machine 10 shown in FIG. 1 is a crank press having a column (frame) 20, a crankshaft 21, a connecting rod 22, a main slide 24, a sub slide 26, a bolster 27 on a bed 28, and the like.

  The main slide 24 is guided by a guide portion provided in the column 20 so as to be capable of reciprocating in a straight direction (vertical direction in FIG. 1).

  The main slide 24 and the sub slide 26 constitute a cylinder-piston mechanism (hydraulic cylinder). The main slide 24 corresponds to the cylinder of the hydraulic cylinder, and the sub slide 26 corresponds to the piston of the hydraulic cylinder. The sub-slide 26 is disposed so as to be capable of reciprocating with respect to the main slide 24 in the same direction as the straight direction in which the main slide 24 moves.

  The leading end of the connecting rod 22 provided on the crankshaft 21 is connected to the main slide 24. A rotational driving force is transmitted to the crankshaft 21 through a servo motor, a reduction gear, etc. (not shown). When the crankshaft 21 rotates, the main slide 24 passes through the crankshaft 21 and the connecting rod 22. The sub-slide 26 is moved up and down in FIG.

  Further, pressure oil can be supplied from the hydraulic circuit 9 to the lowering hydraulic chamber 25a of the hydraulic cylinder, and the pressure oil supplied from the hydraulic circuit 9 to the lowering hydraulic chamber 25a causes the sub slide 26 to be main. It becomes a power source for lowering relative to the slide 24. The power source for raising the sub-slide 26 relative to the main slide 24 is a force generated by supplying air pressure from the air tank 7 to the ascending-side hydraulic chamber 25b or from the lower die via the upper die. Covered by the force of the press load and die cushion force.

  The crankshaft 21 is provided with an angular velocity detector 14 and an angle detector 16 for detecting the angular velocity and angle of the crankshaft 21, and between the main slide 24 and the sub-slide 26, the sub-slide 26 relative to the main slide 24 is provided. A relative position detector 17 for detecting a relative position is provided. The angular velocity detector 14 may acquire the angular velocity signal by differentiating the angle signal output from the angle detector 16.

  An upper die (die) 31 a is attached to the sub-slide 26, and a lower die (punch) 31 b is attached to the bolster 27. The mold 31 (upper mold 31a, lower mold 31b) in this example is for molding a hollow cup-shaped (drawer-shaped) product closed on top.

  Between the upper mold 31a and the lower mold 31b, there is a heel presser plate 34, the lower side of the heel presser plate 34 is supported by a cushion pad via a plurality of cushion pins 35, and a material is set on the upper side (contact) To do). A die cushion force is applied to the eaves pressing plate 34 through cushion pads and cushion pins 35 during molding of the material.

<Hydraulic circuit>
The hydraulic circuit 9 used in the press machine 10 mainly includes an accumulator 1, a hydraulic pump / motor 2, a servo motor 3 connected to the rotary shaft of the hydraulic pump / motor 2, a pilot operation check valve 4, and an electromagnetic valve 5 and a relief valve 6.

The accumulator 1 is set at a gas pressure of about 1 to 5 kg / cm 2 and 10 kg / cm 2.
Accumulate hydraulic oil in a low pressure state (substantially constant low pressure) of about 2 or less and play the role of a tank.

  One port of the hydraulic pump / motor 2 is connected to the lower hydraulic chamber 25a of the hydraulic cylinder via the pilot operation check valve 4, the other port is connected to the accumulator 1, and the hydraulic pump / motor 2 is Depending on the torque applied from the servo motor 3 and the hydraulic pressure acting on both ports, the motor rotates in the forward direction (the side that pressurizes the descending hydraulic chamber 25a) and in the reverse direction (the side that depressurizes the descending hydraulic chamber 25a). To do.

  The pilot operation check valve 4 reduces the load of the servo motor 3 (+ hydraulic pump / motor 2) in the non-working process (at least the upper half of the slide stroke) in one cycle operation of the press (slide). In addition, even when the servo motor 3 is in a no-load state (torque 0 state), the pressure in the lowering hydraulic chamber 25a can be kept constant, and the sub slide 26 is held at the lower end (limit) with respect to the main slide 24. For pilot operation, as an example, pressure acting on a port on the lowering hydraulic chamber 25a side of the hydraulic pump / motor 2 is used.

  The electromagnetic valve 5 plays a role of forcibly releasing the pressure acting on the descending hydraulic chamber 25a. It is not used during normal operation (when functioning) but is used during maintenance (before mechanical disassembly).

  In addition to the pressure normally generated by controlling the motion, the relief valve 6 causes the pressure oil to move to a substantially constant low pressure (accumulator 1) side when an unexpected abnormal pressure acts on the lowering hydraulic chamber 25a. Play a role of escape.

  The pressure acting on the port on the lowering side hydraulic chamber 25a side of the hydraulic pump / motor 2 and the pressure acting on the accumulator 1 side port of the hydraulic pump / motor 2 are detected by pressure detectors 11 and 12, respectively. Further, the angular velocity of the servo motor 3 is detected by an angular velocity detector 13.

<Sub slide controller for press machine>
FIG. 2 is a block diagram showing an embodiment of a sub-slide controller that controls the sub-slide of the press machine 10 shown in FIG.

  As shown in FIG. 2, the sub-slide controller 100 mainly includes a relative position command device (relative position command means) 51, proportional controllers 52 and 53, position control compensators 54 and 55, and a relative position detector (relative position detection). Means) 17, subtracters 80 and 81, and adders 83 and 84.

  The control by the sub-slide controller 100 is a first method in which a deviation amount between the two is amplified via the proportional controller 52 so that the relative position detection signal follows the relative position command signal of the sub-slide 26 with respect to the main slide 24. The servo motor 3 is driven based on a second operation amount signal (a torque command signal of the servo motor 3) amplified via the proportional controller 53 to the deviation amount between the operation amount signal and the angular velocity signal of the servo motor 3. Based on shape. The proportional controller 52 is responsible for relative position control, and the proportional controller 53 is responsible for ensuring dynamic stability (returning the delayed phase).

  The position control compensators 54 and 55 are not absolutely necessary for realizing the present invention, and are desirably provided for improving controllability. The position control compensator 54 corrects the force due to the hydraulic pressure acting on the lower hydraulic chamber 25a of the hydraulic cylinder and the unbalanced force due to gravity, and the position control compensator 55 is a force (for example, a force acting on the control system from the outside). , Molding force) is reduced.

  Next, the sub slide controller 100 will be specifically described.

  The relative position commander 51 outputs a relative position command signal for vibrating the sub-slide 26 to the subtractor 80 for a predetermined period within the press cycle. The vibration conditions (vibration frequency and vibration width) of the sub-slide 26 (upper mold 31a) can be controlled by the frequency and amplitude of the relative position command signal output from the relative position command device 51.

  The relative position detection signal indicating the relative position of the sub-slide 26 with respect to the main slide 24 is added from the relative position detector 17 to the other input of the subtractor 80. A deviation signal obtained by subtracting the relative position detection signal from the command signal is obtained, and this deviation signal is output to the proportional controller 52. The proportional controller 52 amplifies the input deviation signal and outputs it to the subtractor 81 as a first manipulated variable signal.

  An angular velocity signal indicating the angular velocity of the servo motor 3 is added from the angular velocity detector 13 to the other input of the subtractor 81, and the subtractor 81 obtains a deviation between the first operation amount signal and the angular velocity signal, This deviation signal is output to the proportional controller 53. The proportional controller 53 amplifies the input signal and outputs it to the adder 83 as a second manipulated variable signal.

  A feedforward signal generated from the position control compensator 55 based on the angular velocity signal of the servo motor 3 and the second manipulated variable signal is added to the other input of the adder 83. A signal obtained by adding the two input signals is output to the adder 84. A feedforward signal corresponding to the pressure of the descending hydraulic chamber 25a detected by the pressure detector 11 from the position control compensator 54 is added to the other input of the adder 84, and the adder 84 has two inputs. A signal obtained by adding the signals is output to the servo amplifier 61 as a torque command signal for the servo motor 3.

  The sub-slide controller 100 calculates a torque command signal for controlling the torque of the servo motor 3 as described above, and outputs the calculated torque command signal to the servo motor 3 via the servo amplifier 61. The hydraulic cylinder is driven via the hydraulic pump / motor 2 driven by the motor 3 so that the relative position of the sub-slide 26 follows the relative position command.

  When the pressure in the lower hydraulic chamber 25a of the hydraulic cylinder is reduced after press molding, the rotational shaft torque generated in the hydraulic pump / motor 2 exceeds the drive torque of the servo motor 3, and the hydraulic pump / motor 2 The servo motor 3 is rotated (regenerative action). The electric power generated by the regenerative action of the servo motor 3 is regenerated to the AC power source 62 via the servo amplifier 61 and the DC power source 63 with a power regeneration function.

[Vibration experiment]
FIG. 3 is a view showing a state in which a material is formed (drawing) by an upper die (die) 31a and a lower die (punch) 31b. FIG. 3 (a) shows a state during drawing, and FIG. b) shows a hollow cup-shaped product 30 that has been drawn. In FIG. 3B, 30a is a flange portion, 30b is a cylindrical portion, and 30c is a bottom portion.

  As shown in FIG. 3A, the upper die 31 a is moved in the downward direction, and a molding force is applied to the material 32 between the lower die 31 b fixed on the bolster 27. As the drawing process proceeds, a die cushion force is applied to the flange portion of the material 32 via the flange pressing plate 34, thereby preventing wrinkles generated by the circumferential compressive force acting on the flange portion.

  In the case of performing the drawing process as described above, vibration experiments for applying various vibrations to the upper mold 31a were performed.

<Common processing conditions>
Press slide (main slide): 5 spm (strokes / minute)
Vibration application position (mm): 50 to 5.5 above bottom dead center
Die cushion:
Die cushion stroke: From 78mm above the bottom dead center [transformation setting] Slide position above the bottom dead center (mm): 78 ~ 35, 35 ~ 20, 20 ~ 5
Die cushion load (kN): 160, 160-50, 50-40
[Material] Material: SUS304
Thickness: 1mm
Diameter: 300mm
[Mold] Diaphragm diameter: 150mm
Aperture ratio: 50%
<Experimental waveform and outline>
Hereinafter, the experimental results of the drawing process performed for each of the operating conditions (1) and (2) will be shown.

[Operating conditions (1)]
When the main slide 24 is normally operated by rotating the crankshaft 21 at a constant angular velocity and the servo die cushion is effectively used (the die cushion force is effectively transformed). ]]
In addition to the operating condition (1), the sub-slide 26 is vibrated with respect to the main slide 24 at 20 Hz and a vibration width (total amplitude) of 0.2 mm. FIGS. FIG. 5 is a waveform diagram showing a sub-slide position, a press load, and a sub-slide relative position in the drawing process when the press machine 10 is operated under the condition (1). FIGS. It is a wave form diagram which shows the sub slide position, press load, and sub slide relative position in the drawing process at the time of operating the press machine 10 in 2).

  In this example (experiment), as described above, the material is SUS304, the thickness is 1 mm, and the drawing rate is 50%.

  Both the operating conditions (1) and (2) are formed at a constant number of strokes / minute (5 spm) in a crank press. In addition, both use a servo die cushion device, and the die cushion force is transformed (decreased) in accordance with the drawing process progress (stroke) to improve the drawability.

  Nevertheless, since the basic drawing conditions are difficult, in the case of the operating condition (1), cracks occurred in the material at the end of drawing as shown in FIG. In the waveform diagram (b) showing the press load, the portion where the load is abruptly reduced indicates the moment when the material breaks. At that time, a large change is also shown in the waveform diagram (a) indicating the sub-slide position and the waveform diagram (c) indicating the relative position of the sub-slide, and these are the large accelerations generated by the fracture of the material. This is because the output signal of each detector instantaneously becomes abnormal.

  Therefore, the operating condition was changed from the operating condition (1) to the operating condition (2). In the operating condition (2), the sub-slide 26 has a vibration frequency of 20 Hz and a vibration width of 0.2 mm (amplitude 0.1 mm) compared to the operating condition (1) in which the sub-slide 26 is not vibrated. It differs in that it vibrates.

  With this operating condition (2), the friction between the mold and the material could be reduced, and a series of drawing processes could be performed without causing cracks in the material.

  That is, in the case of the operating condition (2), the factor that enables the drawing process is a friction reducing action between the mold and the material caused by the vibration of the slide.

  In the experiment, a disk-shaped material is deep-drawn and formed into a shape including a flange portion 30a, a cylindrical portion 30b, and a bottom portion 30c as shown in FIG.

  When the drawing process is started, the center part of the material that becomes the bottom at the end of the process is pushed to the tip of the punch (FIG. 3B). As the processing progresses, the flange portion is pulled in the radial direction and compressed in the circumferential direction to increase the plate thickness. The material is supplied to the cylindrical portion by plastic flow of the material from the flange portion which is caused by being pulled by the bottom portion pressed by the punch.

  Then, the highest tensile stress is generated in the material at the boundary portion between the radius portion of the punch and the cylindrical portion (outer peripheral portion of the punch tip), and the plate thickness of the material is also reduced.

  The friction between the material and the mold is a factor that hinders plastic flow in the drawing process, and causes material breakage at the boundary between the radius portion and the cylindrical portion of the punch.

  In the operating condition (1), the material is compressed in the circumferential direction as the drawing process proceeds, and the plastic flow of the material from the flange portion to the cylindrical portion is not hindered while suppressing generation of wrinkles in the flange portion that increases the plate thickness. Thus, even when an attempt was made to adjust the die cushion force (wrinkle pressing force against the flange portion), breakage of the boundary portion was inevitable.

  However, by processing under the operating condition (2), the frictional force between the material and the mold was reduced, the plastic flow of the material was promoted, and the drawing could be performed without breaking.

  Next, experimental results of drawing processing performed for each of the following operating conditions (3) to (5) are shown.

[Operating conditions (3)]
In addition to the operating condition (1) described above, when the sub-slide 26 is vibrated with respect to the main slide 24 at a vibration frequency of 3 Hz and a vibration width (total amplitude) of 4.1 mm [Operating condition (4)].
In addition to the operating condition (1), when the sub-slide 26 is vibrated with respect to the main slide 24 at a vibration frequency of 5 Hz and a vibration width (total amplitude) of 2.0 mm [Operating condition (5)]
In addition to the operating condition (1), the sub-slide 26 is vibrated with respect to the main slide 24 at 5 Hz with a vibration width (total amplitude) of 2.5 mm. The operating conditions (3) to (5) are described above. Compared with the operating condition (2), the sub-slide 26 has a low frequency and a large vibration width.

  6A to 6D show the sub-slide position, the sub-slide relative position, the sub-slide speed, and the press load (sub-slide load) in the drawing process when the press machine 10 is operated under the operating condition (3). FIG.

  The operating condition (3) is a special control compared to the operating condition (2), and the ascending speed of the sub-slide 26 is ensured by ensuring a large vibration width and the sub-sliding speed does not reverse (does not become greater than 0). It is a condition that controls the descent speed and the speed change timing.

  The vibration of the sub-slide 26 due to the operating condition (3) does not cause the speed of the sub-slide 26 to become 0 or more (not reverse) (see FIG. 6C), thereby reducing the stress partially acting on the material. A series of drawing processes could be performed without cracking the material.

  7A to 7D show the sub-slide position, sub-slide relative position, sub-slide speed, and press load (sub-slide load) in the drawing process when the press machine 10 is operated under the operating condition (4). FIG.

  In the operation condition (4), the vibration frequency of the sub-slide 26 is larger than that in the operation condition (3), while the vibration width is smaller.

  Even in the case of the operating condition (4), the speed of the sub-slide 26 does not become 0 or more (see FIG. 7C), which can reduce the stress partially acting on the material, and crack the material. A series of drawing processes could be performed without causing them.

  FIGS. 8A to 8D show the sub-slide position, sub-slide relative position, sub-slide speed, and press load (sub-slide load) in the drawing process when the press machine 10 is operated under the operating condition (5). FIG.

  In the operating condition (5), the vibration width of the sub-slide 26 is changed from 2.0 mm to 2.5 mm compared to the operating condition (4).

  In the case of the operation condition (5), the vibration width of the sub-slide 26 is larger than that in the operation condition (4). As a result, the speed of the sub-slide 26 is reversed (exceeds 0) at the final stage of drawing (see FIG. c)), and drawing failed (the material broke at the end during molding). In the waveform diagram (d) showing the press load, the portion where the load is abruptly reduced indicates the moment when the material breaks. At that time, the waveform diagram (a) showing the sub-slide position, the waveform diagram (b) showing the sub-slide relative position, and the waveform diagram (c) showing the sub-slide speed also show significant changes. This is because the output signal of each detector instantaneously becomes abnormal due to the large acceleration generated by the material breaking.

  In the case of the operating conditions (3) and (4), when the upper mold descends stepwise over time (FIGS. 6 (a) and 7 (a)), the descending is almost stopped or relaxed. The partial stress relaxation effect of the material that occurs over time reduces the stress generated in the material at the boundary where breakage easily occurs, and increases the limit drawing ratio.

  However, if the sub-slide 26 rises (speed reverses) during the molding as shown in the operating condition (5) (FIG. 8C), the drawing process fails.

  Consider a state where the punch is set on the lower die, the die is set on the upper die, and the material flange is pressed against the die by the pressing force of the die cushion.

  If the ascending speed due to the vibration of the sub-slide 26 with respect to the main slide 24 exceeds the descending speed of the main slide 24 during the processing, the sub-slide 26 (upper die) is used even though the main slide 24 is descending due to the combined speed. ) Will rise against the lower mold.

  Then, since the flange portion is pressed against the die by the die cushion force (ie, pressing force), the flange portion is lifted together with the sub slide 26. That is, the material moves in the direction of coming out of the punch attached to the lower mold.

  When the punch moves away from the material, the frictional force acting between the side surface of the punch and the inner surface of the material cylindrical portion is the direction opposite to the plastic flow direction of the material of the cylindrical portion during drawing with respect to the material cylindrical surface. Will act.

  Thus, when the direction of the frictional force acting between the side surface of the punch and the inner surface of the material cylindrical portion is reversed, the flow of the material to the boundary portion is hindered and breakage occurs during the processing.

  Although the experimental results under the above operating conditions (1) to (5) are a part of the experimental results, the operating conditions (vibration conditions (vibration frequency, vibration width) of the sub-slide 26) are changed, and a large number A vibration experiment was conducted.

  FIG. 9 is a graph showing the correlation result of the vibration frequency-vibration width of the sub-slide when the material is completed without breaking based on the experimental results of drawing.

  As shown in FIG. 9, the area A where the drawing process has been successful is an area where the vibration frequency of the sub-slide is 9 Hz to 33.3 Hz and the vibration width is 0.05 mm to 0.5 mm. In other region B where processing was successful, the vibration frequency of the sub-slide is 0.8 Hz or more and less than 11.6 Hz, the vibration width is 0.04 mm or more, and a value that does not reverse the direction of the speed during molding of the sub-slide. This is the area.

  That is, the region A having a relatively high frequency is considered to have been successfully drawn by a friction reducing action between the mold and the material, and the region B having a relatively low frequency relieves a stress partially acting on the material. It is considered that the drawing process was successful due to the partial stress relaxation action.

  Therefore, by oscillating the sub-slide so as to satisfy the vibration condition in the region A or B shown in FIG. 9, good press molding can be performed even under relatively difficult press molding conditions.

[Other Embodiments of Relative Position Commander 51]
FIG. 10 is a block diagram showing another embodiment of the relative position commander 51 shown in FIG.

  A relative position commander 51a shown in FIG. 10 includes a position commander 511, a vibration commander 512, and an adder 513.

  The position commander 511 outputs a position command signal indicating the position of the sub-slide 26 with respect to the main slide 24 for a predetermined period set by the crank angle. Outputs a position command signal for control.

  A press machine that drives a slide with a crankshaft or a link mechanism has a low variable speed response of the slide, and in particular, a machine having a flywheel cannot control the speed of the slide, but outputs the position command signal from the position commander 511. By controlling the relative position of the sub-slide 26 based on this position command signal, the slide motion of the sub-slide 26 to which the upper mold is attached can be controlled. Thereby, for example, it is possible to achieve a slide motion in which the descending speed of the sub-slide 26 during molding is made constant or the sub-slide 26 is stopped at a bottom dead center for a certain period of time.

  Similar to the relative position commander 51 shown in FIG. 2, the vibration command unit 512 outputs a vibration command signal indicating the frequency and width of vibration of the sub-slide 26 for a predetermined period set by the crank angle.

  The adder 513 adds the position command signal applied from the position commander 511 and the vibration command signal applied from the vibration commander 512, and outputs the added signal as a relative position command signal for the final sub-slide 26. .

[Others]
The present invention can be applied not only to a crank press but also to other press machines such as a mechanical press and a hydraulic press. Moreover, although the case where oil was used as a working fluid of the cylinder-piston mechanism comprised by the main slide and the sub slide was demonstrated, not only this but water and other liquids may be used. Furthermore, the present invention can be applied to a press machine or the like that drives one main slide by a plurality of connecting rods.

  Moreover, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 2 ... Hydraulic pump / motor, 3 ... Servo motor, 9 ... Hydraulic circuit, 10 ... Press machine, 11, 12 ... Pressure detector, 13, 14 ... Angular velocity detector, 16 ... Angle detector, 17 ... Relative position detector , 21 ... crankshaft, 22 ... connecting rod, 24 ... main slide, 25a ... descending hydraulic chamber, 26 ... sub-slide, 31 ... mold, 31a ... upper mold, 31b ... lower mold, 34 ... saddle pressing plate, 51, 51a ... Relative position commander, 52 ... Proportional controller, 54, 55 ... Position control compensator, 100 ... Sub-slide controller, 511 ... Position commander, 512 ... Vibration commander

Claims (12)

A main slide arranged to be able to reciprocate in a straight direction;
Main slide drive means for reciprocating the main slide;
A sub-slide on which a mold is mounted, the sub-slide being arranged so as to be reciprocally movable in the same direction as the main slide, and a pressure applied to the main slide being transmitted via hydraulic pressure;
Sub-slide drive means for reciprocally driving the sub-slide relative to the main slide, wherein the sub-slide is reciprocated in the same direction as the main slide by changing the hydraulic pressure. Driving means;
Vibration control means for controlling the sub-slide drive means so that the sub-slide vibrates,
A press machine for forming a material by cooperation of the main slide driving means and the sub slide driving means.   The vibration control means controls the sub-slide driving means so that the vibration frequency of the sub-slide is 9 Hz or more and 33.3 Hz or less, and the vibration width of the sub-slide is 0.05 mm or more and 0.5 mm or less. The press machine according to claim 1.   The vibration control means includes a sub-slide driving means so that a vibration frequency of the sub-slide is 11.6 Hz to 33.3 Hz and a vibration width of the sub-slide is 0.05 mm to 0.5 mm. Or the vibration frequency of the sub-slide is 0.8 Hz or more and less than 11.6 Hz, and the vibration width of the sub-slide is 0.04 mm or more, the value that does not reverse the direction of the speed during molding of the sub-slide The press machine according to claim 1, wherein the sub-slide driving unit is controlled so as to satisfy the following conditions.   The vibration control means detects a relative position command means for outputting a relative position command signal indicating a relative position of the sub slide with respect to the main slide, and detects a relative position of the sub slide with respect to the main slide, Relative position detection means for outputting a relative position detection signal indicating the detected relative position, and a relative position command signal output from the relative position command means and a relative position detection signal output from the relative position detection means. The press machine according to any one of claims 1 to 3, wherein the sub-slide driving means is controlled based on the following. A position command device that outputs a position command signal indicating the position of the sub-slide relative to the main slide, and a vibration command device that outputs a vibration command signal indicating the frequency and width of vibration of the sub-slide. ,
The press according to claim 4, wherein the relative position command means adds the vibration command signal output from the vibration command device to the position command signal output from the position command device and outputs the relative position command signal. machine.   The main slide and the sub slide constitute a cylinder-piston mechanism, the main slide is one of a cylinder and a piston of the cylinder-piston mechanism, and the sub slide is a cylinder of the cylinder-piston mechanism. The press machine according to claim 1, which is the other of the piston and the piston.   The press machine according to claim 6, wherein the sub-slide driving means includes a servo motor and a hydraulic pump / motor that is driven by the servo motor and supplies pressurized fluid to a hydraulic chamber of the cylinder-piston mechanism.   The press machine according to any one of claims 1 to 7, wherein the main slide drive means moves the main slide continuously through a connecting rod of the press machine for at least a molding period. In a press machine having a main slide disposed so as to be reciprocally movable in a straight direction and a sub-slide on which a mold is mounted, the sub-slide being disposed so as to be reciprocally movable in the same direction as the main slide. ,
A liquid that drives the main slide in the straight direction, drives the sub-slide in the straight direction in conjunction with the drive of the main slide, and is pressurized in conjunction with the drive of the main slide at least during molding of the material. Transmitting a pressing force to the sub-slide via pressure;
Periodically changing the hydraulic pressure during molding of the material, and vibrating the sub-slide;
A slide control method for a press machine.   The slide control method for a press machine according to claim 9, wherein the vibration of the sub-slide is set to have a vibration width and frequency that reduce friction of a sliding surface between the material and the mold.   The vibration of the sub-slide is set such that the vibration frequency of the sub-slide is 9 Hz or more and 33.3 Hz or less, and the vibration width of the sub-slide is 0.05 mm or more and 0.5 mm or less. The slide control method of the press machine as described.   The vibration of the sub-slide is set such that the vibration frequency of the sub-slide is 11.6 Hz to 33.3 Hz, and the vibration width of the sub-slide is 0.05 mm to 0.5 mm, or The vibration frequency of the sub-slide is set to 0.8 Hz or more and less than 11.6 Hz, the vibration width of the sub-slide is set to 0.04 mm or more, and a value that does not reverse the direction of speed during molding of the sub-slide. 11. The slide control method for a press machine according to claim 10, wherein:

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