JP2006026653A - Press - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a press provided with a high-accuracy die height compensator while suppressing the manufacturing cost and securing durability. <P>SOLUTION: The press in which rotational power is converted into vertical drive of a slide 51 through a linkage mechanism 60, is provided with a first eccentric shaft 11 for receiving the rotational power, three-shaft link 12 one of the three shafts of which is eccentrically rotationally driven with the first eccentric shaft 11, connecting rod 13 one end of which is connected to another shaft of the three-shaft link 12 freely rotatably and the other end of which is connected to the slide 51 or the upper end of a plunger 14 the lower end of which is connected to the slide 51 freely rotatably, two-shaft link 16 one end of which is connected to the rest one shaft of the three-shaft link 12 freely rotatably, a second eccentric shaft 70 for eccentrically rotating the other end of the two-shaft link 16 and a drive source 71 for rotationally driving the second eccentric shaft 70. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a press machine that drives a slide up and down via a link mechanism, and more particularly to a mechanism that corrects die height.

During work forming, the die height may change due to thermal deformation of the main body frame. The die height refers to the distance from the upper surface of the bolster on which the lower die is placed to the lower surface of the slide to which the upper die is attached when the slide is at the bottom dead center. If the die height changes, stable molding cannot be performed, so it is necessary to correct the die height.
Usually, the slide has a die height adjusting device, and a screw interposed between the connecting rod or the plunger and the slide is rotated using an AC motor to move the slide position in the vertical direction.

  In addition, when an eccentric load is applied to the slide during workpiece forming, the slide is inclined and defects in the molded product are likely to occur. Even if the mold is adjusted in consideration of the tilt of the slide, when this mold is set in another press machine, the molded product often has a defect, and it takes a lot of time to adjust the mold. . This is due to a so-called machine difference in which the deflection generated in the frame of each press machine is different even when the same load is applied.

  As means for correcting the tilt of the slide, Patent Document 1 discloses a technique in which a plurality of die height adjusting devices provided in one slide are provided with respective electric motors, and these electric motors are individually controlled. .

JP 2001-121297 (FIGS. 1 and 2)

In order to correct a change in die height due to thermal deformation of the main body frame, the die height must be adjusted with high accuracy. Therefore, an electric servo motor or a hydraulic servo system that performs servo control is required as a drive source for the die height adjusting device. However, since these drive sources are precision instruments, there is a problem in durability if they are provided in a slide that generates an impact of several tens of G during molding.
In addition, since a molding load is directly applied to the screw portion of the die height adjusting device, a screw having a large screw diameter and screw pitch is required. In order to control the rotation of such a large screw, a torque must be applied to the screw to sufficiently overcome the frictional force of the screw surface. For this reason, a large-capacity servo control drive source must be used, leading to a significant increase in manufacturing cost.

This is also true when correcting the tilt of the slide due to an eccentric load or the like using a die height adjusting device provided on the slide.
In this case, a plurality of die height adjusting devices provided on one slide are individually controlled. However, a plurality of high-priced, large-capacity servo control drive sources must be used, which further increases the manufacturing cost.

  An object of the present invention is to provide a press machine equipped with a high-precision die height correcting device while reducing manufacturing costs and ensuring durability.

  In order to achieve the above object, according to the present invention, in a press machine that converts rotational power into a vertical drive of a slide via a link mechanism, a first eccentric shaft that receives the rotational power and one of the three axes are A three-axis link that is driven to rotate eccentrically by the first eccentric shaft, and a plunger that has one end pivotably connected to the other one axis of the three-axis link and the other end connected to the slide, or a lower end connected to the slide. A connecting rod that is pivotably connected to the upper end of the shaft, a biaxial link whose one end is pivotally connected to the remaining one of the three-axis links, and the other end of the biaxial link is eccentrically rotated. The second eccentric shaft and a drive source that rotationally drives the second eccentric shaft are provided.

  Preferably, at least the three-axis link, the two-axis link, the second eccentric shaft, and the drive source are set as one set, and a plurality of the sets are arranged for one slide.

  Further, it is effective that the driving source is an electric servo motor.

  According to the present invention, the second eccentric shaft is provided at the other end portion of the biaxial link connected to one shaft of the triaxial link, and the second eccentric shaft is rotated to rotate the second eccentric shaft. The position is moved to correct the slide die height. Since the link mechanism is interposed between the second eccentric shaft and the slide, the amount of movement in the vertical direction of the slide is smaller than the amount of movement of the shaft position of the other end of the two-axis link, and the slide position is minute. It becomes possible to correct. In addition, since a molding load is not directly applied during molding, it is not necessary to increase the capacity of the drive source for rotating the second eccentric shaft, and the manufacturing cost can be reduced. Further, since the drive source is installed in the crown, the impact during molding is much smaller than in the slide, and the durability of the drive source is not hindered.

  Then, at least the three-axis link, the two-axis link, the second eccentric shaft, and the rotation drive source are set as one set, and a plurality of the sets are arranged for one slide, and each drive source is individually set. By controlling, it is possible to easily correct the inclination of the slide due to the eccentric load or the like. Further, correction for machine differences can be easily performed.

As a drive source for rotating the second eccentric shaft, if the output shaft of the electric servo motor is connected to the second eccentric shaft directly or via a speed reducer, the amount of minute movement can be easily controlled and structurally This is preferable for die height correction because it is simple in terms of control.
A lever may be provided on the second eccentric shaft, and an electric servo cylinder may be provided at the tip.

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a front view showing a main part of a slide drive mechanism of a press machine according to the present invention. FIG. 2 is a cross-sectional view of the second eccentric shaft portion (cross-section BB in FIG. 1).
In the press machine according to the present invention, the rotational power from the main motor (not shown) is converted into the vertical drive of the slide 51 via the link mechanism 60. The configuration of the link mechanism 60 will be described in detail below.
The first eccentric shaft 11 is pivotally supported by the crown 53. Specifically, the first eccentric shaft 11 having the shaft center 11a is fixed to the main gear 58b supported by the shaft 58a that is supported by the crown 53 at a position eccentric from the shaft center O of the shaft 58a. One shaft 12a of a three-axis link 12 having three shafts 12a, 12b, and 12c is rotatably fitted to the first eccentric shaft 11, and one end of a connecting rod 13 is pin-connected to the other shaft 12b. ing. The other end of the connecting rod 13 is pivotally connected to the slide 51 by a pin. Normally, the four connecting rods 13 are supported in consideration of the horizontal balance of the slide 51. However, if sufficient balance can be obtained, the supporting rods 13 may be supported by fewer than four connecting rods 13.
In the following, in this specification, the connecting portion of the connecting rod 13 or the plunger 14 (described later) and the slide 51 will be referred to as a point.

One end of the biaxial link 16 is pivotally connected to the remaining one shaft 12c of the triaxial link 12, and the other end of the biaxial link 16 is pivotally supported by a crown 53. The eccentric part 70a of the second eccentric shaft 70 is rotatably inserted (see FIG. 2).
More specifically, the second eccentric shaft 70 has rotary shafts 70b and 70b disposed at both ends of the eccentric portion 70a, and the rotary shafts 70b and 70b are rotatable by brackets 73 and 73 fixed to the crown 53. It is supported.
An output shaft of a speed reducer 72 is connected to one end of the second eccentric shaft 70 through a coupling 74. An electric servo motor 71 is fixed to the speed reducer 72. The speed reducer 72 is installed on the crown 53 via a bracket.
An encoder 32 is provided at the other end of the second eccentric shaft 70 via a coupling 75, and detects the rotation angle α of the second eccentric shaft 70.
Note that the speed reducer 72 and the electric servo motor 71 are not limited to being integrated with each other, and may be separate parts in which both are connected by a connecting tool. Furthermore, the electric servo motor 71 may be directly connected to the second eccentric shaft 70 via a connector without using a reduction gear.
Further, the encoder 32 may be incorporated in the electric servo motor 71.

  FIG. 3 is a diagram conceptually illustrating the slide position control method according to the present invention. Here, the eccentric distance between the axial center O of the shaft 58a and the axial center of the shaft 12a of the triaxial link 12 (same as the axial center 11a of the first eccentric shaft 11) is R, and the rotation angle of the first eccentric shaft 11 is Let θ. In addition, the distance between the shafts 12a and 12b of the triaxial link 12, the distance between the shafts 12b and 12c, and the distance between the shafts 12a and 12c are L2, L3, and L4, respectively. Let L5. The length of the biaxial link 16 is L1, and the relative distance between the rotation axis center 70b of the second eccentric shaft 70 and the axis center O of the shaft 58a is (X, Y). Further, the relative distance between the axial center of the other end shaft 16a of the biaxial link 16 (same as the axial center of the eccentric shaft 70a of the second eccentric shaft 70) and the axial center O of the shaft 58a is (X16, Y16). .

  When the rotation of the output shaft of the electric servo motor 71 is fixed and the main gear 58b is rotationally driven by the electric main motor via the clutch, the shaft 12a of the three-axis link 12 rotates about the axis O of the shaft 58a. As a result, the shaft 12b also moves along a locus of a predetermined closed curve. This movement causes the slide 51 to move up and down via the connecting rod 13. This vertical motion of the slide 51 becomes a predetermined link motion. The link motion includes the eccentric distance R of the first eccentric shaft 11, the rotation angle θ of the first eccentric shaft 11, the distances L 2, L 3 and L 4 between the two axes of the triaxial link 12, and the length of the connecting rod 13. A predetermined function determined by the mechanical relationship between the length L5, the length L1 of the biaxial link 16, and the relative distance (X16, Y16) between the other end shaft 16a of the biaxial link 16 and the axial center O of the shaft 58a. It is expressed by a formula. The relative distance (X16, Y16) includes the rotation angle α of the second eccentric shaft 70 rotated by the electric servo motor 71, the eccentric amount r of the second eccentric shaft 70, and the rotation axis of the second eccentric shaft. And a predetermined functional expression determined by a mechanical relationship between the relative distance (X, Y) between the axis 58a and the axis center O of the axis 58a. Therefore, by rotating the first eccentric shaft 11 to a predetermined angle with the electric servo motor 71 set at a predetermined rotation angle, the slide 51 can be moved in the vertical direction based on the predetermined relational expression. It becomes possible.

The slide motion will be described with reference to FIG. 4 is the rotation angle θ (press angle θ) of the first eccentric shaft 11, and the vertical axis indicates the position of the slide.
For example, it is assumed that the other end shaft 16a of the biaxial link 16 is fixed at the position shown in FIG. When the first eccentric shaft is rotated once by the rotational power from the main motor, the slide draws a motion as indicated by C1-C2-C3 in FIG.
Further, when the other end shaft 16a of the biaxial link 16 is rotated counterclockwise and fixed at a position indicated by 16a 'in FIG. 3, the entire triaxial link 12 is brought into a standing state, so that D1-D2-D3 in FIG. Draw motion as shown in.
The position of the bottom dead center Dn of the motion D is lower than the bottom dead center Cn of the motion C.

When the slide is lowered from the top dead center along the motion C1 and reaches the predetermined pressing angle θ1, the second eccentric shaft is rotated and the position of the other end shaft of the biaxial link 16 is set to 16a ′. Transition from motion C1 to motion D2 (θ1-θ2).
Thereafter, the slide moves along the motion D2 and passes through the bottom dead center.

When the slide rises to a predetermined press angle θ3, the second eccentric shaft is rotated to return the position of the other end shaft of the biaxial link 16 to 16a, and the motion D2 is shifted to the motion C3 (press angle θ3-θ4). ).
Thereafter, the slide moves along the motion C3 and reaches the top dead center.

Next, a hardware configuration of a control device for performing the above-described slide motion control will be described with reference to FIG.
In the vicinity of the main gear 58b, a press angle sensor 31 including a pulse encoder or the like that detects a rotation angle θ (referred to as a press angle here) of the first eccentric shaft 11 is provided. In addition, a slide position sensor 33 that detects the vertical movement position of the slide 51 is provided, and the slide position sensor 33 includes, for example, a linear sensor provided between the slide 51 and the upright 52. Further, as described above, the encoder 32 that detects the rotation angle α of the second eccentric shaft is provided. Detection signals from these sensors 31, 32, and 33 are input to the controller 30.

  Further, the present control device is provided with a storage means 30a, and includes a slide position table representing correspondence between preset slide motion data and the die height correction value h and the rotation angle α of the second eccentric shaft. It is remembered.

  The controller 30 is mainly composed of a computer device such as a personal computer or a high-speed arithmetic device such as a PLC (programmable logic controller, so-called sequencer), and inputs detection values of the sensors 31, 32, 33, Based on the detected value, the speed command of the electric servo motor 71 is calculated with reference to the slide motion data and the die height correction table stored in the memory 30a, and this is output to the servo amplifier 34 to output the electric servo motor 71. Control position and speed.

  The servo amplifier 34 inputs the rotation speed of the motor from the electric servo motor 28 as a feedback signal, and based on the input speed command from the controller 30 and the deviation value between the feedback signal, the speed of the electric servo motor 28 is adjusted. I have control.

  Note that the controller 30 also performs an interpolation (for example, linear interpolation) using values in the die height correction table.

  FIG. 6 is a flowchart showing the procedure of a control method for die height correction according to the present invention.

In step S1, the basic die height H corresponding to the next die to be used is read. Next, the die height correction value hi for each point is read (step S2). Here, the subscript i represents each point. The basic die height H and the die height correction value hi may be input by an operator from the input unit, or values stored in the storage unit 30a may be read.
Then, an actually set die height Hi (= H−hi) for each point is calculated (step S3), and a master point and a slave point are determined (step S4). Here, the point with the highest setting die height Hi is set as a master point, and the other points are set as slave points.
Instead of reading the die height correction value hi in step S1, molding is performed without performing the die height correction at the first time, and the die height correction value is calculated from the die height measurement value measured by the linear sensor corresponding to each point. Also good.

In step S5, the rotation angle αi of the electric servo motor 71 corresponding to the die height correction value hi is obtained. The correspondence between the die height correction value hi and the rotation angle αi is stored in the storage device as a correspondence table. For example, the rotation angle α of the electric servo motor 71 is stored for each die height correction value of 0.1 mm, and the fraction of the die height correction value smaller than 0.1 mm is linearly interpolated. Of course, curve interpolation may be performed.
Note that a calculation formula (including an approximate formula) may be stored instead of the correspondence table.

  In step S6, it is confirmed that the position of the slide has been lowered to a predetermined height, and in step S7, the electric servo motor 71 at each point is rotated by a rotation angle αi corresponding to the die height correction value hi. The above die height correction is completed by the time molding starts.

  In step S8, press molding is started. In step S9, it is confirmed that the bottom dead center has been reached. In step S10, the slide position (die height) Hi 'at each point at the bottom dead center is measured by a linear sensor.

  In step 11, hi '= Hi'-(H-hi) is obtained. Here, when the value of the master axis is hm ′ = Hm ′ − (H−hm) (step S12), Δhi = hi′−hm ′ = Hi ′ − (H−hi) −hm ′ is When the second eccentric shaft 70 with respect to the point is fixed, the correction value of the die height correction with respect to the slave point is obtained (step S13).

  In step S14, it is determined whether hm 'is greater than or equal to a threshold ha. If smaller than the threshold value ha, the process proceeds to the next step. On the other hand, if the threshold value ha is not less than the threshold value ha, the basic die height H is replaced with H-hm '(step S15), and the process proceeds to the next step.

  In step S16, press molding is terminated. In step S17, it is confirmed that the position of the slide has been raised to a predetermined height, and in step S18, each electric servo motor is rotated to the basic die height H state.

  In step S19, it is determined whether or not the next workpiece is to be molded. If not, the die height correction value hi = hi + Δhi is replaced and stored (step S20), and the press machine is stopped.

  When forming the next workpiece in step S19, the die height correction value hi = hi + Δhi is set (step S21), the process returns to step S5, and the next press working is performed.

  In the flowchart of the above-described embodiment, the work timing is measured based on the slide position, but a press angle may be used instead of the slide position.

In the above-described embodiment, the drive source of the second eccentric shaft 70 is the servo motor 71, but a swing cylinder 71A may be used as shown in FIG. In this case, the controller 30 inputs a signal of the rotation angle α of the second eccentric shaft 70 from the encoder 32 and issues a command to the servo valve 34A. The servo valve 34A controls the inflow and outflow of pressure oil from the hydraulic source 77A to the swing cylinder 71A, and sets the rotation angle α of the swing cylinder 71A to a predetermined value.
In FIG. 7, the return circuit to the oil tank is omitted, but a hydraulic circuit generally used for servo control of the hydraulic actuator is used.

In the above-described embodiment, the drive source of the second eccentric shaft 70 is the servo motor 71, but an electric servo cylinder 71B may be used as shown in FIG. Here, (a) is a cross-sectional view similar to FIG. 2, and (b) is a side view of (a).
The electric servo cylinder 71B is obtained by converting the rotational power into linear power by using an electric servo motor 71a as a power source. The rod is moved in and out by forward and reverse rotation of the electric servo motor 71a, and moves like a rod of a fluid cylinder. An example of a power conversion mechanism that converts rotational power into linear power is a ball and screw mechanism. In some cases, a speed reducer is interposed between the output shaft of the electric servo motor 71a and the power conversion mechanism.

  In order to use the electric servo cylinder 71B that performs linear motion as a drive source for the rotation of the second eccentric shaft 70, the lever 76 is fixed to the second eccentric shaft 70, and the tip of the electric servo cylinder 71B is attached to the tip of the lever 76. Is attached to the shaft (shaft 76a). Further, the electric servo cylinder 71B main body is pivotally attached to the crown 53 (shaft 71b). When the rod of the electric servo cylinder 71 </ b> B is taken in and out in this state, the second eccentric shaft 70 rotates through the lever 76.

  As shown in FIG. 8B, the distance between the shafts 70b and 71b, the distance between the shafts 76a and 70b, and the distance between the shafts 76a and 71b are L6, L7, and L8, respectively. L6 and L7 are mechanically constant values. By inserting / removing the rod of the electric servo cylinder 71B, L8 changes, and the rotation angle α of the second eccentric shaft 70 is uniquely determined by L8.

  In the embodiment described above, the drive source of the second eccentric shaft 70 is the servo motor 71, but a hydraulic cylinder 71C may be used as shown in FIG. Here, (a) is a cross-sectional view similar to FIG. 2, and (b) is a side view of (a).

In this case, the above-described swing cylinder 71A and electric servo cylinder 71B are combined.
In order to use the hydraulic cylinder 71 </ b> C that performs linear motion as a driving source for the rotation of the second eccentric shaft 70, the lever 76 is fixed to the second eccentric shaft 70, and the tip of the hydraulic cylinder 71 </ b> C is pivoted to the tip of the lever 76. Wear (shaft 76a). Further, the hydraulic cylinder 71C main body is pivotally attached to the crown 53 (shaft 71b). When the rod of the hydraulic servo cylinder 71 </ b> C is taken in and out in this state, the second eccentric shaft 70 rotates through the lever 76.

  The distance between the shafts 70b and 71b, the distance between the shafts 76a and 70b, and the distance between the shafts 76a and 71b are L6, L7, and L8, respectively. L6 and L7 are mechanically constant values. By inserting and removing the rod of the hydraulic cylinder 71C, L8 changes, and the rotation angle α of the second eccentric shaft 70 is uniquely determined by L8.

When the hydraulic cylinder 71C is used, the controller 30 inputs a signal of the rotation angle α of the second eccentric shaft 70 from the encoder 32 and issues a command to the servo valve 34A. The servo valve 34A controls the inflow and outflow of the pressure oil from the hydraulic source 77C to the hydraulic cylinder 71C so that the rod insertion / extraction length of the hydraulic cylinder 71C becomes a predetermined value.
In FIG. 9, the return circuit to the oil tank is omitted, but a hydraulic circuit generally used for servo control of the hydraulic actuator is used.

  According to the above-described embodiment, the connecting rod 13 is directly connected to the slide. However, the plunger 14 may be interposed between the connecting rod 13 and the slide 51 as shown in FIG. That is, the plunger 14 has a lower end connected to the slide 51 and an upper end connected to the other end of the connecting rod 13 so as to be rotatable. The outer periphery of the plunger 14 is slidably fitted in the vertical direction with the inner periphery of the guide 15 fixed to the lower portion of the crown 53.

It is a front view which shows the slide drive mechanism principal part of the press machine which concerns on this invention. It is sectional drawing which shows the 2nd eccentric shaft drive mechanism which concerns on this invention. It is explanatory drawing of the slide position control method which concerns on this invention. It is explanatory drawing of the slide motion which concerns on this invention. It is a hardware block diagram of the control apparatus which concerns on this invention. It is a flowchart showing the control method of the die height correction based on this invention. It is sectional drawing which shows other embodiment of the 2nd eccentric shaft drive mechanism which concerns on this invention. It is sectional drawing which shows other embodiment of the 2nd eccentric shaft drive mechanism which concerns on this invention. It is sectional drawing which shows other embodiment of the 2nd eccentric shaft drive mechanism which concerns on this invention. It is a front view which shows other embodiment of the slide drive mechanism of the press machine which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... 1st eccentric shaft, 11a ... Shaft center, 12 ... 3-axis link, 12a, 12b, 12c ... Shaft, 13 ... Connecting rod, 14 ... Plunger, 15 ... Guide, 16 ... 2-axis link, 51 ... Slide, 52 ... Upright, 53 ... Crown, 58 ... Slide drive mechanism, 58a ... Shaft, 58b ... Main gear, 58c. ..Gear train, connecting rod, 59 ... tie rod, 60 ... link mechanism, 70 ... second eccentric shaft, 71 ... drive source.

Claims (3)

In a press machine that converts rotational power into vertical drive of a slide (51) through a link mechanism (60),
A first eccentric shaft (11) for receiving the rotational power;
A three-axis link (12) in which one of the three axes is eccentrically driven by the first eccentric shaft (11);
One end of the three-axis link (12) is pivotally connected to the other shaft, and the other end is turned to the slide (51) or the upper end of the plunger (14) whose lower end is connected to the slide (51). A connecting rod (13) that is movably connected,
A biaxial link (16) having one end rotatably connected to the remaining one axis of the triaxial link (12);
A second eccentric shaft (70) that eccentrically rotates the other end of the biaxial link (16);
A press machine comprising a drive source (71) for rotationally driving the second eccentric shaft (70). At least the three-axis link (12), the two-axis link (16), the second eccentric shaft (70), and the drive source (71) are set as one set, and this set includes a plurality of sets for one slide (51). The press machine according to claim 1, wherein the press machine is provided. The press machine according to claim 1 or 2, wherein the drive source (71) is an electric servo motor.

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